(introductory text...)

by
AK Draper
J van der Pols
PS Shetty
JVGA Durnin*

1997
Human Nutrition Unit
Department of Public Health and Policy
London School of Hygiene and Tropical Medicine
and
*Department of Human Nutrition
University of Glasgow

© London School of Hygiene and Tropical Medicine 1997
PHP Departmental Publication No. 26
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Acknowledgements

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(introductory text...)

The 1985 FAO/WHO/UNU Consultation adopted the principle of using measures of energy expenditure rather than energy intake to estimate energy requirements. Because data on habitual daily energy expenditure are required for this, the Consultation emphasized the importance of Basal Metabolic Rate (BMR) and suggested that the factorial approach be used to arrive at estimates of energy expenditure. The factor with which to multiply the BMR to estimate total energy expenditure would depend upon the level of physical activity of an individual. The factor may be used for single activities or may be used to obtain an integrated value for overall periods of work. James and Schofield (1990) have used the term "Physical Activity Ratio" (PAR) for single activities. This is a ratio which expresses the energy cost of an individual activity per minute as multiples of BMR per minute. For integrated activities over a period of time they have coined the term "Integrated Energy Index" (IEI) which is the energy cost of an activity or occupation, including the pauses of rest involved in conducting that activity, expressed on a minute or hourly basis and calculated again as a ratio of the BMR. The "Physical Activity Level" (PAL) expresses the total energy expenditure and hence requirement for a 24 hour period as a function of BMR. This enables categorization of daily levels of physical activity indulged in by the individual into light (sedentary), moderate or heavy activity levels in both males and females.

Different values representing the factor may be used depending upon whether it is obtained either by direct measurements of the energy cost of physical activity per se, or, whether the cost of a particular activity has been derived from data in the published literature. Potential sources of error are numerous when total energy expenditure is derived from the latter. These depend upon the method used to measure the energy cost of the activity, the corrections made for body weight differences and the variations with age and sex of subjects (although the assumption is that corrections of body weight normalizes for the gender differences). Another potential and major source of error when published data is used is the relationship of the energy cost of the activity to other related ancillary activities, such as rest pauses or other short term diversions related to the activity itself. Distinguishing whether an activity is "pure" or "adulterated" is not only arbitrary, but is very often guess work. If the activity is of a short term nature, it is likely to a "pure" one. If, on the other hand, the activity continues for a long enough period of time, it is certain to be "adulterated" by rest pauses, diversionary activity or secondary activities unrelated to the primary task. Hence, knowledge of the duration of the activity becomes essential to decide which factor to use in order to estimate 24-hour energy expenditure.

A range of physical activities are performed by an individual over a period of a day. The types of activity are likely to vary from day to day and over a period of time. Some activities are essential for the individual and community. Many of them may be categorized as occupational activities, which are life sustaining economic activities. Leisure time activities have been described as "discretionary" activities and are considered as desirable for the well-being of the community and health of the individual and population. This latter category includes optional household or domestic tasks, socially desirable activities and activities aimed at achieving physical fitness and the promotion of health. Estimates of energy costs of habitual activities of all types are essential to enable calculations of daily energy expenditure, which in turn are needed to calculate energy requirements.

The factor used to multiply BMR to estimate energy expenditure depends on the type, level and duration of physical activity. The different types of activity undertaken by an individual can be identified and the time spent on each activity measured. The energy cost of each activity can then be obtained by measuring the subject's oxygen uptake while performing the task or type of activity. There are numerous studies of the energy cost of different activities made by this method and, although they do not provide the net energy cost of each activity above the BMR, they do provide a measure of the total energy expended during the period of physical activity. The energy cost of an activity is usually expressed per minute and the total energy expended over a period of 24 hours is then calculated based on the duration of time spent on each activity.

The energy cost of a standardized form of physical activity or exercise performed in a laboratory or clinical setting is easy to measure and it is also possible to estimate the variability in the energy costs between individuals while performing the same task in such standardized conditions. This does not hold good in a field setting when the energy cost of habitual daily activities are measured in individuals and estimates of variabilities between and within individuals are also obtained. The difficulties in field measurement are compounded by the fact that it is difficult to obtain an accurate value for those tasks that combine a variety of movements, some of which demand the use of most parts of the body, while others may involve only small muscle groups without major weight bearing or movement of the body. The between individual variations in the energy costs of such habitual activities are also likely to be large because different individuals may perform the same type of task in quite different ways.

It is important to recognize that differences in body weight and body composition of individuals will influence the energy cost of activities. It is difficult to generalize on the extent to which differences in body weight affect the energy expenditure for a given type of physical activity. A relation between the energy cost and the body weight of an individual is to be expected when the task involves moving the body, but not when it involves work on external objects. Many types of daily activity are likely to be a mixture of both types. Using published data to generate generalizable energy costs for types of physical activity encountered in daily life needs to take this into consideration, while distinguishing from published data on energy expenditure measurements made during standardized activities in laboratory settings, which, in addition, may very often provide additional data on body composition and other parameters.

In order to convert the energy cost of different activities into estimates of total daily energy expenditure information is needed on the time spent by an individual on each type of activity conducted over a period of 24 hours. It is impractical to measure the cost of all activities carried out by an individual. Far more important than taking large numbers of measurement is the accurate recording of the time spent on each "important"¹ activity. Information on this can be obtained relatively easily and inexpensively by use of recalls, questionnaires or completion of activity diaries by the individual. However, more accurate estimates would require the use of "time and motion" studies using observers, which will make the study more difficult and expensive. It is important to remember that both these sets of methods are likely to influence the normal habitual activity of the individual and hence his/her total daily energy expenditure. It is also essential to recognize that the pattern of activity is meant to reflect habitual daily energy expenditure and that energy expenditure varies not only from day to day and week to week, but also over seasons. Substantial variations in the energy expenditure of individuals are known to occur over long periods and under different circumstances. This should be borne in mind when considering energy expenditure over long periods of time.

(¹ "Important" activity is defined as either occupying a significant period of time over the 24-hour period, or else involving considerable physical effort.)

Available data on the energy cost of human physical activities have been summarized in the past. The major publications include those by Orr and Leitch (1938) and by Durnin and Passmore (1955; 1967). Summary tabulations of the energy costs of activities based on these earlier data have been provided in the Technical Report based on the International Consultation (FAO/WHO/UNU 1985) and later by James and Schofield (1990). The information is still somewhat inadequate because for several types of activities the number of subjects on whom measurements have been made is very small. This bibliography has been systematically compiled and attempts to bring together all the published material in the literature in recent years. It is aimed at nutritionists, physiologists and other health professionals interested in the energy cost of physical activity and the estimation of daily energy expenditure and the energy requirements of individuals and population groups.

PS Shetty
AK Draper

References

Durnin JVGA & Passmore R (1955). Human energy expenditure. Physiol. Rev. 35, 801840.

Durnin JVGA & Passmore R (1967). Energy, work and leisure. London: Heinemann Education Books.

FAO/WHO/UNU (1985). Energy and protein requirements. Rome: FAO.

James WPT & Schofield EC (1990). Human energy requirements. Oxford: Oxford University Press.

Orr JB & Leitch I (1938). The determination of the calorie requirements of man. Nutr. Abstr. Rev 7, 509-529.

2. Methods

This comprehensive bibliography of studies of the energy costs of physical activities in humans is based on the published literature over three decades between the years 1966 and 1995. The cut-off date of 1966 was chosen because the earlier published literature related to the energy cost of physical activity has already been synthesized in Durnin and Passmore's classic treatise "Energy, Work and Leisure" published in 1967. Within this broad remit, the inclusion/exclusion criteria used to select studies were:

1) Study design: all studies in which original measurements of energy expenditure, a description of the performed activity, a description of the measurement method, and results were included.
2) Age groups: all age groups (children, adolescents, adults and the elderly) were included.
3) Sex: both men and women were included.
4) Activity type: both natural or habitual activities and standardized activity or exercise performed either in the field or laboratory were included. Standardized activities are defined as those which have been carried out in a laboratory under standardized conditions, some of which may be an attempt to simulate daily activities such as walking or running, while others, such as stepping or weight lifting, have been carried out only for the purpose of estimating physiological or mechanical efficiency.
5) Health status of subjects: only studies of subjects who were healthy and ablebodied were included. Studies of the obese and obese after weight loss were included. Studies of those who were in a disease state, hospitalized or those with a physical disability, such as amputees, were excluded. Studies which examined drug effects on energy metabolism were also excluded.

Studies were identified by systematic hand searches of Index Medicus and Nutrition Abstracts Reviews from 1966 to 1995 inclusive. These were cross-checked by computer searches of the electronic version of Index Medicus, Medline. In the course of searching these sources many review papers were also encountered. The more useful of these have been included in the bibliography in a final section.

The bibliography is arranged in sections by age group, and for adults by activity type and by sex (abstracts with sex unspecified have generally been included in the 'Men' section). Four broad headings of activity type have been used: activities common to everyday life; occupational activities; sport and recreational activities; and standardized activities. Studies of children and the elderly have not been sub-divided by sex and activity type because of the paucity of studies. Within each section, English language publications are listed first arranged alphabetically by author followed by foreign language papers. Original abstracts for all studies are included. Where not available, summaries have been supplied.

3. Children and adolescents

1. Banerjee B & Saha N (1972): Energy intake and expenditure of Indian schoolboys. Br.J.Nutr. 27, 483-490.

Sixteen Indian schoolboys, aged 12-14 years and resident in Singapore, were tested for the determination of energy cost, pulmonary ventilation (PV) and oxygen (02) consumption at rest and at various daily activities; their height, body-weight, pulse and blood pressure were also measured. An energy balance study was made by estimating from a diary of measured activities the 24 h energy intake and output. PV and 02 consumption during running showed positive correlations (r=0.4 and r=0.3 respectively) with mean height and body-weight. High positive correlations (r=0.8) were obtained between mean post-excercise recovery pulse, 02 consumption and PV. The daily mean calorie intake and output of the subjects were found to be 2108 kcal (8.85 MJ) and 1811 kcal (7.60 MJ) respectively. The boys gained an average of 2.2 kg in weight and 0.7 cm in height in 2 months. They did not suffer from any mental retardation, they were physically fit, free from disease and did their daily routine work satisfactorily.

2. Banerjee B & Saha N (1982): Energy cost of some common physical activities of Chinese schoolboys. Ann.Nutr.Metab. 26, 360-366.

Fourteen Chinese schoolboys aged 12-14 years, resident in Singapore coming from affluent homes, were tested for the determination of energy cost, pulmonary ventilation (PV) and oxygen (02) consumption at rest and during some common physical activities by using a Max-Planck respirometer and Lloyds gas analysis apparatus. The study was undertaken for comparison with the results of a similar investigation of Indian schoolchildren of the same age-group living in a hostel under hostel discipline and diet in Singapore reported earlier. The energy cost (kcal/min, kJ/min) in these Chinese children was found to be significantly higher, but the energy cost per kilogram body weight per hour was found to be significantly lower than in the Indian children. PV in litres per minute was significantly higher in Chinese schoolboys during all physical activities except lying at rest, sitting and running. O2 consumption in litres per minute was also significantly higher during all activities except lying at rest and sitting.

3. Blackburn ML & Calloway DH (1974): Energy expenditure of pregnant adolescents. J.Am.Diet.Assoc. 65, 24-30.

Energy expenditure of female adolescents residing in a metabolic unit was measured at rest and during various household activities and standard work task performed during pregnancy and in some cases, postpartum. Diaries of daily activities were kept by a second, comparable group of free-living pregnant adolescents enrolled in a city high school program. Energy cost of activities measured in the first group was used to estimate the daily energy needs of the second group. Basal metabolic rate was 17% higher during the third trimester of pregnancy than postpartum, but there was no difference between the data if values were corrected for the difference in body weight. Energy expenditure per unit of mass was also the same for quiet sitting and standing activities during and after pregnancy. When work levels were heavier and involved body movement, work pace was slowed, and energy expenditure per unit of time was less during pregnancy than postpartum. Pace appeared to the dominant variable, since the cost of fixed work tasks (treadmill and bicycle) was the same per kilogram per minute during pregnancy and postpartum. The energy cost of a task, eg stair climb, was greater for the pregnant woman, in proportion to her increased body mass. Pregnant adolescents were extremely sedentary, spending about 90% of their time lying down or seated. Their average energy expenditure for basal metabolism and activity was computed to be 2,200 kcal per day. With a daily allowance of 150 kcal for deposition of maternal tissues and conceptus, total metabolizable energy need was about 2,400 kcal per day. If there were continued maternal growth, need would be increased proportionately.

4. Bradfield RB, Chan H. Bradfield NE & Payne PR (1971): Energy expenditures and heart rates of Cambridge boys at school. Am.J.Clin.Nutr. 24,1461-1466.

The energy expenditure of 54 primary school boys in Cambridge, England, was measured for 3 to 5 days during classes, and organized and unorganized play, using a technique that does not interfere with usual activities. The measurement of weight, height, and skin folds indicated the boys were on the high side of normal for both height and weight as judged by British standards. The central tendency of classroom activities was 2.1 to 2.7 kcal/min and the lunch play period 3.0 kcal/min. There was no significant difference between the energy expenditures of the fattest and leanest children of the group. The school program and types of games are described.

5. Bradfield RB, Paulos J & Grossman L (1971): Energy expenditure and heart rate of obese high school girls. Am.J.Clin.Nutr. 24,1482-1488.

The energy expenditure and physical activity of nonobese and obese high school girls participating in the same school program were assessed by three different methods over different periods of time. The continuous monitoring of heart rate and use of individual regressions of heart rate on oxygen consumption to estimate energy expenditure showed no significant differences between nonobese and obese girls during physical education classes, during school classroom activities, and after school work or play. Three-day activity assessments showed that both groups were very inactive, 70% of the time was spent either in sleep or very light activites. Assessment of relative participation in physical education class did not reveal different trends between obese and nonobese subjects.

6. Brooke OG, Alvear J & Arnold M (1979): Energy retention, energy expenditure, and growth in healthy immature infants. Pediatr.Res. 13, 215-220.

Energy balance studies were done during 10-29 days on 15 immature infants of mean birth weight 1581 9. Mean gross energy intake was 757 kJ/kg (181 kcal) and 79% of this was retained, so that metabolizable energy was 602 kJ/kg (143 kcal). Mean resting metabolic rate was 244 kJ/kg (58.1 kcal), and it increased with advancing maturity. Minimum resting metabolism averaged 199 kJ/kg (47.5 kcal). Energy expended in activity increased with maturity, but amounted to less than 17% of the total energy turnover. Postprandial metabolism caused the mean VO2 to rise by 17% in the hour after a feed, and during 24 hrs resulted in consumption of energy equivalent to about 10% of the resting metabolism. Stored energy amounted to 230 kJ/kg (55 kcal) and was linearly related to weight gain (r = 0.92). Energy cost of weight gain was 24 kJ/g (5.7 kcal) and energy stored in new tissue was 16.8 kJ/g (4.0 kcal). Maintenance energy requirement at zero growth rate was about 270 kJ/kg (64 kcal).

7. Chessex P. Reichman BL, Verellen GJ, Putet G. Smith JM, Heim T & Swyer PR (1981): Relation between heart rate and energy expenditure in the newborn. Pediatr.Res. 15, 10771082.

This study defines the relationship between heart rate and metabolic rate in newborn infants and evaluates the accuracy of prediction of metabolic rate from heart rate. Continuous measurements of oxygen uptake, CO2 production, respiratory quotient, and cumulative heart rate were performed using computerized, open-circuit indirect calorimetry and on-line electrocardiogram monitoring over periods of 1 to 24 hr (mean 4.5 fur). Metabolic rate was calculated from the individual oxygen uptake and respiratory quotient. Thirty-five studies were performed in 16 infants (birthweight 0.75 to 3.1 kg; gestational age, 26 to 42 wk; mean +/- S.D. age at study, 26.5 +/- 15.7 days; study weight, 1.78 +/- 0.5 kg). Metabolic rate (car/kg . min) and heart rate (beats/min) were compared minute by minute (8269 measurements) and showed a close third degree polynomial relationship for heart rates of 110 to 230/min (y = 0.0000291x3 + 0.01685x2 -2.93x + 197; r = 0.99; P less than 0.001); however, at heart rates above 140 beats/min, a linear relationship was found (r = 0.997; P less than 0.001). From cumulated heart rate measurements, factors defining metabolic rate per heart beat were also determined: for each beat 51.8 +/- 6.8 microliter of oxygen/kg are consumed and 0.258 +/0.03 car/kg (1.1 J/kg) are expended. Despite the wide variation in birthweight, gestational age, method of feeding, and clinical characteristics, there was a remarkable consistency in the heart rate-metabolic rate relationships. A further 10 studies were performed in a similar group of infants to assess the predictive value of the previously defined relationships and showed a mean percentage deviation of 5.7 +/- 4% from the measured value. It was concluded that in the varied group of newborns studied, heart rate correlates closely with metabolic rate and that cumulative heart rate measurements enable the estimation of metabolic rate in newborn infants. This provides a method of monitoring energy expenditure and caloric requirements over long periods.

8. Cooke CB, McDonagh MJ, Nevill AM & Davies CT (1991): Effects of load on oxygen intake in trained boys and men during treadmill running. .J.Appl.Physiol 71, 1237-1244.

Department of Sport and Exercise Sciences, University of Birmingham, United Kingdom. This investigation examines the effects of vertical and horizontal loading on the 02 intake (V02) response of children (n = 8) and adults (n = 8) to treadmill running. In unloaded running, the children required a significantly greater VO2 (P less than 0.001) than the adults [mean difference 7 ml.kg-1.min-1 (18.5%)]. There was no significant difference in the VO2 response of the children and the adults to either vertical or horizontal loading. Vertical loading with 5 and 10% of body mass did not produce a significant increase in the VO2 response of either group. In contrast, horizontal loading produced a significant increase (P less than 0.001) in both groups. The consistent response to the two forms of loading suggests that there is no difference between children and adults in the apparent efficiency of running with an external load. Stride frequency showed a significant increase with vertical loading (P less than 0.001) and a significant decrease with horizontal loading (P less than 0.001) in both groups.

9. Davies CT (1980): Metabolic cost of exercise and physical performance in children with some observations on external loading. Eur.J.Appl.Physiol 45, 95-102.

The metabolic cost (VO2) of running was studied on a motor-driven treadmill in nine athletic boys, five athletic girls, and nine active boys aged 11-15 years and the results compared with their performance times during racing out of doors. On 15 of the children additional observations of the effects of external loading on aerobic power output were made. The results showed that VO2 was proportional to body weight in children but when expressed ml.kg-1.min1, VO2 for a given speed of running was significantly higher in children than expected from previously collected data on adults. There were no significant differences between aerobic cost of running of the athletic boys, girls, or the active boys. The increased VO2 ml.kg-1.min-1 in children appeared to be independent of stride length and frequency but external loading equivalent to 5% of body weight reduced VO (ml.kg-1.min-1), particularly at the higher speeds. It was suggested in young active and athletic children due to their relatively light body weights and highly developed aerobic power outputs, that the required frequency of leg movement was not optimally matched to the force necessary to produce the most economic conversion of aerobic energy into mechanical work. Thus, in competitive events their performance times were related to their maximal aerobic power output (r=-0.75) but their times were always inferior to those which one might have expected from previous aerobic power weight data collected on adult male and female athletes.

10. Devadas RP, Anuradha V & Mathai J (1977): Energy intake and expenditure of selected adolescent girls. Ind.J.Nutr.Diet. 14, 31-37.

The energy intake and expenditure of 12 adolescent Indian college girls were studied. Basal metabolic rate was between 31.59 and 55.80 kcal/m²h. Energy expenditure of girls residing in a hostel, 2843 kcal, was higher than that of girls staying with their families, 2642 kcal. Energy expenditure of both groups appeared to be higher than energy intake, 2460 and 2412 kcal daily

11. Duggan MB & Milner RDG (1986): The maintenance energy requirement for children: an estimate based on a study of children with infection associated to underfeeding. Am.J.Clin.Nutr. 43, 870-878.

An estimate of the maintenance energy requirement (MER) has been based on energy balance data from children fed at different levels of intake during and after acute measles. The relationship between apparent energy balance (B) and the metabolizable energy (ME) was investigated by regression analysis. The relationship between B and ME in 34 balance studies is given by B = 0.79 ME - 211.9 (r = 0.91). The ME at zero B [268.3 kJ (64.1kcal)/kg/24h] is equivalent to the maintenance energy requirement (MER). Paired data on 16 children were used to study the relationship between MER and the resting metabolic rate (RMR). The relationship between MER and RMR during measles, is at low levels of energy intake, is given by MER = 1.52 RMR - 140.9 kJ/kg/24h (r = 0.79). The factorial relationship between MER and RMR was estimated, and also the safe level of intake to supply the MER when ME represents between 76% and 84% of gross energy (GE). The safe level of GE intake, between 381 and 416 kJ/kg/24h (ie between 91.1 and 99.4 kcal/kg/24h) is very close to the WHO/FAD (1973) recommendations for growing children.

12. Duggan MB & Milner RDG (1986): Energy metabolism in healthy black Kenyan children. Br.J.Nutr. 56, 317-328.

Twenty-four healthy black Kenyan children, mean age 29 (SD 19) months, were studied over a 24 h period. Energy expenditure (EE) was determined using a ventilated-hood indirect calorimeter; measuring oxygen consumption and carbon dioxide production. Metabolizable energy intake was measured in twenty children. Anthropometric measurements were used to estimate surface area and lean body weight. The mean daily intake of metabolizable energy was 338.4 (SE 28.4) kJ; 70% of gross dietary energy being provided by carbohydrate. The level of postprandial EE was significantly (P < 0.05) higher than the resting level (112.6 (SE 0.47) and 11.38 (SE 0.37) kJ per h respectively) while the level of the postprandial respiratory quotient (RQ) was similar to the resting level (0.94 (SE 0.02) and 0.98 (SE 0.03) respectively). In 33% of total observations of the resting RQ the value was more than 1.0. These findings suggest that short-term fat storage may be a normal feature of metabolism in children, and also that the energy cost of (postprandial) fat synthesis is increased by a high-carbohydrate diet. Values for the resting metabolic rate and various estimators of body size were compared using regression analysis. It was evident that, in these young children with considerable variation in body composition, body weight remained a satisfactory metabolic size estimator.

13. Freedson PS, Katch VL, Gilliam TB & MacConnie S (1981): Energy expenditure in prepubescent children: influence of sex and age. Am.J.Clin.Nutr. 34, 1827-1830.

The purpose of this investigation was to examine the relationship between energy expenditure and speed for 6- and 7-yr-old children and to compare these data to published data for adults. Eight subjects (four boys, four girls) completed three treadmill tests at 67, 94, and 127.5 m . min-1 (k = 12 trials for the boys, 12 trials for the girls). Heart rate was monitored continuously and oxygen uptake (VO2) and carbon dioxide production (VCO2) were determined at each speed in order to estimate caloric expenditure. Sex differences were observed in the metabolic and heart rate responses to exercise. In comparison to the females, the energy expenditure (kcal . min-1) was 16 (p less than 0.05), 11 (p greater than 0.05) and 14 (p less than 0.05) percent higher for the males at the slow, medium, and fast speeds, respectively. Additionally, heart rate was 13 beats . min- 1 lower (p less than 0.05) for the males at a speed of 94 m. min-1. Differences in kcal . kg . min-1 between children and adults were observed (children higher). In contrast to adults' linear increase in energy expenditure with increasing speed, a curvilinear pattern was observed for prepubescent children. It was concluded that these sex and age effects must be considered when attempting to quantify children's daily energy expenditure and caloric requirements.

14. Gandra YR & Bradfield RB (1971): Energy expenditure and oxygen handling efficiency of anemic children. Am.J.Clin.Nutr. 24, 1451-1456.

The energy expenditure and oxygen handling efficiency of nonanemic and anemic primary school children was measured at school and at play in an isolated jungle fishing village before and after iron therapy. Typical daily energy expenditure was not dependent upon the degree of anemia. Standardized tests of oxygen handling efficiency showed that 88% of the variations in energy expenditure could be accounted for by multiple regression of heart rate, weight, and hemoglobin. Oxygen handling efficiency was affected adversely by abnormal hemoglobin levels.

15. Goran Ml, Kaskoun M, Johnson R. Martinez C, Kelly B & Hood V (1995): Energy expenditure and body fat distribution in Mohawk children. Pediatrics, 95, 89-95.

Department of Medicine and Nutritional Sciences, University of Vermont, Burlington. Epidemiologic studies suggest that Native Americans, including the Mohawk people, have a high prevalence of obesity, diabetes, and cardiovascular risk. However, current information on alterations in related variables such as energy metabolism and body composition in Native Americans is almost exclusively limited to already obese Pima adults living in the Southwest. The aim of this study was to characterize energy metabolism and body composition in young Mohawk children (17 girls, 11 boys; aged 4 to 7 years) as compared to Caucasian children (36 girls, 34 boys; aged 4 to 7 years). Total energy expenditure was measured by doubly labeled water, postprandial resting energy expenditure by indirect calorimetry, and activity energy expenditure was derived from the difference between total and resting energy expenditure. Fat and fat-free mass were estimated from bioelectrical resistance, and body fat distribution was estimated from skinfolds and circumferences. RESULTS. There were no significant effects of ethnic background or sex on body weight, height, or body mass index. Fat free mass was significantly higher in boys and fat mass was significantly higher in girls, with no effect of ethnic background. Chest skinfold thickness, the ratio of trunk skinfolds: extremity skinfolds, and the waist: hip ratio were significantly higher in Mohawk children by 2.5 mm, 0.09 units, and 0.03 units, respectively, independent of sex and fat mass. Total energy expenditure was significantly higher in Mohawk children compared to Caucasian (100 kcal/day in girls, 150 kcal/day in boys), independent of fat free mass and sex, due to a significantly higher physical activity-related energy expenditure. CONCLUSION. These data suggest that: 1) body fat is more centrally distributed in Mohawk relative to Caucasian children, and this effect is independent of sex and body fat content; 2) Mohawk children have a greater total energy expenditure than Caucasian children, independent of fat free mass, due to greater physical activity-related energy expenditure.

16. Ho Z. Zi HM, Bo L & Ping H (1988): Energy expenditure of pre-school children in a subtropical area. Wld.Rev.Nutr.Diet. 57, 75-94.

This study examines the appropriate energy intakes for preschool children in a subtropical area of China. A series of measurements were made on 181 children in four different seasons over a period of 1.5 years: body surface area, basal metabolic rate, dietary intakes, and the specific dynamic action of 8 common foods. The total energy expenditure of a sub-sample of children was calculated via daily activity records and measurements of the energy costs of 21 routine activities made using indirect calorimetry. The average daily energy expenditure for boys was 1,077.6 +- 37.0 kcal and for girls was 1,020.5 +- 43.7 kcal. Using this as the basis to calculate energy intake requirements and making allowances for growth and digestibility, an RDA of 1,500 of kcal/d was calculated as acceptable for this group of 5 year old children. [not original abstract].

17. Holmer I (1972): Oxygen uptake during swimming in man. .J.Appl.Physiol 33, 502-509.

It is possible to set the water flow rate with great accuracy in a recently constructed swimming flume, i.e., a kind of swimming "treadmill". Oxygen uptake, heart rate, and blood lactate concentrations were measured in three female and six male adult subject, with varying proficiency in swimming, while subjects swam three styles at different speeds. The same determinations were made during exercise on a Krogh bicycle ergometer and on a treadmill. The same determinations were made in 12 girl swimmers, 13-18 years old, but only during maximal running and maximal swimming. Minimal oxygen uptake during floating in a vertical position in nine subjects varied from 0.9 to 2.0 I.min^-1. At a given swimming speed the trained swimmers were able to swim with a much lower oxygen uptake than subjects who were not trained swimmers. At a given oxygen uptake trained swimmers also swam much faster than the untrained swimmers. The front crawl proved to be the most economical style, as is the case in competition swimming. The back crawl was somewhat less economical and the breaststroke was the least economical style. Maximal oxygen uptake, maximal pulmonary ventilation, and maximal heart rate were significantly lower in swimming than in running or cycling, respectively.

18. Katch V, Becque MD, Marks C, Moorehead C & Rocchini A (1988): Oxygen uptake and energy output during walking of obese male and female adolescents. Am.J.Clin.Nutr. 47, 2632.

Department of Kinesiology, School of Medicine, University of Michigan, Ann Arbor. Oxygen uptake and steady-rate energy output of 7 obese male and 13 obese female adolescents (greater than 178% ideal body weight) walking at four different speeds (1.167, 1.5667, 1.7833, and 2.125 m/s) were studied. Body composition was measured by hydrostatic weighing, and steady-rate energy output by open circuit spirometry. Energy output was expressed as kJ/min (kcal/min) and indexed to body mass and fat-free mass. A 2-by-4 ANOVA (sex by speed) revealed significant differences in the energy output between the speed conditions. There was no significant difference between the sexes. A nonlinear increase in calorie output with increasing speed indicated a decreasing efficiency with increasing speed of walking. Possible reasons include biomechanical factors such as increased upper-body forward lean needed to maintain balance at faster speeds of movement, increased energy output due to increased inertia, extra energy output needed to accelerate the limbs and torso, and increased body fat.

19. Knuttgen HG (1967): Aerobic capacity of adolesents. .J.Appl.Physiol 22, 655-658.

Average values for a variety of anthropometric and physiologic parameters have been obtained for a representative group of American adolescents (15-18 years old) and of European ancestry. Both male (N = 95) and female (N = 95) subjects were studied at rest and at work on a bicycle ergometer. The mean values for the boys generally exceeded those for the girls, as body size exerted an important influence. At rest the boys had higher values for oxygen consumption, pulmonary ventilation, and metabolic rate VO2 per unit body size); the girls had a higher average heart rate. At maximal work the boys had higher values for oxygen consumption (for boys mean value = 3.34 liters/min, for girls mean value = 1.90 liters/min), pulmonary ventilation, and heart rate (for boys mean value = 196/min, for girls mean value = 193/min); the girls had a higher average ventilatory equivalent. When aerobic capacity was expressed in terms of body weight, the girls had a mean value of 33.6 and the boys 50.3 ml/kg per min. The prediction of aerobic capacity from steady-state heart rate reactions to submaximal work was enhanced by including the person's body weight in the calculation.

20. MacDougall JD, Roche PD, Bar-Or O & Moroz JR (1983): Maximal aerobic capacity of Canadian schoolchildren: prediction based on age-related oxygen cost of running. Int.J.Sports Med. 4, 194-198.

Timed distance runs were administered to a random sample of 2,683 schoolchildren aged 716 years. Oxygen uptake was then measured during level treadmill running over a range of submaximal speeds in a randomly selected subsample of 134 children with approximately equal representation according to age and sex. The VO2 - running speed relationship was found to be related to age, with the younger children having a greater VO2 per kg body weight than the older children when running at the same absolute speed. Based on the relationship found between measured VO2max and VO2max predicted according to field test performance, corrected for age-related differences in running efficiency, VO2max was predicted for all 2,683 children. When expressed per kg of body weight, VO2max was highest in girls at age 11 (approximately 44 ml/kg) and in boys at age 14 (approximately 54 ml/kg); however, differences among ages were nonsignificant. At all ages VO2max for the boys was significantly higher than that for the girls. At all ages, values were higher than those previously reported for Canadian schoolchildren.

21. Maffeis C, Schutz Y. Schena F. Zaffanello M & Pinelli L (1993): Energy expenditure during walking and running in obese and nonobese prepubertal children. J.Pediatr. 123, 193-199.

Department of Pediatrics, University of Verona, Italy. We measured body composition and energy expenditure during walking and running on a treadmill in 40 prepubertal children: 23 obese children (9.3 +/- 1.1 years of age; 46 +/- 10 kg (mean +/- SD)) and 17 nonobese matched control children (9.2 +/- 0.6 years of age; 30 +/- 5 kg). Energy expenditure was assessed by indirect calorimetry with a standard open-circuit method. At the same speed of exercise, the energy expenditure was significantly (p < 0.01) greater in obese than in control children, in both boys and girls. Expressed per kilogram of body weight or per kilogram of fat-free mass, the energy expenditure was comparable in the two groups. Obese children had a significantly (p < 0.01) larger pulmonary ventilatory response to exercise than did control children. Heart rate was comparable in boys and girls combined but significantly higher (p < 0.05) in obese subjects, if boys and girls were analyzed separately. These data indicate that walking and running are energetically more expensive for obese children than for children of normal body weight. The knowledge of these energy costs could be useful in devising a physical activity program to be used in the treatment of obese children.

22. McNaughton JW & Cahn AJ (1970): A study of the energy expenditure and food intake of five boys and four girls. Br.J.Nutr. 24, 345-355.

Assessments were made of the energy expenditure and food intake of five boys and four girls aged between 16 and 20 years. 2. The subjects recorded their activity over a 7-day period and weighed and recorded their food intake over the same period. The energy expended by them in performing specific activities, such as sitting, standing and walking, was measured by indirect calorimetry. The total daily energy expenditure of each subject was then counted. (Values were selected from the literature for the energy cost of the activities which were not measured.) 3. The following range of values was obtained for the energy cost per min of various activities: sitting 1.0-1.8 kcal; standing, 1.2-2.0 kcal; walking 2.0-7.5 kcal; office work 1.1-1.9 kcal; laboratory work 1.4-2.3 kcal; playing table tennis, 4.6 kcal; riding a bicycle, 3.66.0 kcal; running, 5.2-7.5 kcal. 4. The means and standard deviations for daily energy expenditure and for calorie intake. respectively, expressed in kcal, of the individual subjects were: for the boys 2677 +184 and 3348±668, 2285±91 and 2652+418, 2730±263 and 2985±625, 2638±338 and 2379±204, 2594±244 and 3150+692; for the girls 1939±234 and 2340+524, 2261±175 and 2064+376, 2131±148 and 2011±389, 2104±171 and 2454±469. 5. There was no correlation between the daily energy expenditure and calorie intake of any subject, nor was there any relation between the weight of individual subjects and either their total energy expenditure or calorie intake. 6. It is concluded that more precise methods of measuring the energy expenditure and calorie intake of individual subjects would need to be used in order to determine if there is any correlation between these two variables over short periods. 7. The results of this study tend to confirm the findings of other workers that calorie balance is only achieved over periods longer than 7 days.

23. Moore ME, Pond J & Korslund MK (1966): Energy expenditure of pre-adolescent girls. Measurements taken in the basal state and while walking. J.Am.Diet.Assoc. 49, 409-412.

The energy expenditure of twelve pre-adolescent girls was determined when each was in the basal state and while walking at a self-chosen speed. All basal metabolic rates were within +-9 per cent of the standard. Energy used for walking ranged from 53.3 to 90.8 calories per square meter of body surface per hour, or an increase of 119 and 206 per cent, respectively over basal metabolism. Differences in energy used for the same activity may be a factor in the relative ease with which an individual maintains caloric balance.

24. Morgan J & Mumford P (1981): Preliminary studies of energy expenditure in infants under six months of age. Acta Paediatr.Scand. 70, 15-19.

In the study energy expenditure measurements have been made by open circuit calorimetry on a number of occasions on four infants, with special reference to the energy cost of resting metabolism, activity and diet-induced thermogenesis. In addition, for two subjects the energy cost of growth was determined. The energy expended with respect to activity was highly variable among all subjects and it was postulated that this was a factor of great importance in the energy balance of young infants; indeed, the effect of diet-induced thermogenesis was enhanced by activity. A calculation of the total energy required to gain 1 g of wet tissue in two infants was found to be different. As their intakes were 'low' and 'high' though their weight gains were accelerated and slow respectively, the difference in the energy cost of growth has been discussed as a reason for this paradox.

25. Rose J. Gamble JG, Burgos A, Medeiros J & Haskell WL (1990): Energy expenditure index of walking for normal children and for children with cerebral palsy. Dev.Med.Child Neurol. 32, 333-340.

Children's Hospital at Stanford, Palo Alto, CA 94304. Energy expenditure indices (EEI) based on oxygen uptake and heart rate were used to compare the economy of walking at various speeds by normal and cerebral-palsied children. At low walking speeds, EEI values were high, indicating poor economy. At higher speeds the EEI values decreased until a range of maximum economy was reached. For normal children who were capable of walking beyond this range at higher speeds, the EEI increased again. This pattern was noted for both oxygen uptake and heart-rate indices. Mean EEI values based on oxygen uptake and heart rate for normal children were significantly lower and occurred at faster walking speeds than values for children with cerebral palsy. EEI based on either oxygen uptake or heart rate can be used clinically to provide objective information to help evaluate the influence on gait function of surgical intervention, ambulatory aids or orthotics.

26. Rose J. Gamble JG, Lee J. Lee R & Haskell WL (1991): The energy expenditure index: a method to quantitate and compare walking energy expenditure for children and adolescents. J.Pediatr.Orthop. 11, 571 -578.

Division of Orthopaedic Surgery, Stanford University Medical Center, California. Heart rate and walking speed were used to calculate an energy expenditure index (EEI), the ratio of heart rate per meter walked, for 102 normal subjects, age 6-18 years. Heart rate was measured at self-selected slow, comfortable, and fast walking speeds on the floor and on a motor-driven treadmill. At slow walking speeds (37 +/- 10 m/min) the EEI was elevated (0.71 +/- 0.32 beats/m), indicating poor economy. At comfortable speeds (70 +/- 11 m/min) the EEI values decreased to the maximum economy (0.47 +/- 0.13 beats/m). At fast speeds (101 +/13 m/min), the EEI increased (0.61 +/- 0.17 beats/m), indicating poor economy relative to comfortable speeds. A graph of the EEI versus walking speed provides a way to evaluate and compare energy expenditure in a clinical setting.

27. Rose J. Gamble JG, Medeiros J. Burgos A & Haskell WL (1989): Energy cost of walking in normal children and in those with cerebral palsy: comparison of heart rate and oxygen uptake. J.Pediatr.Orthop. 9, 276-279.

Division of Orthopaedics, Children's Hospital, Stanford, Palo Alto 94304. The rate of oxygen uptake can be used to assess energy expenditure during walking, but the necessary instrumentation is cumbersome, expensive, and usually unavailable in the clinical setting. Heart rate is an easily measured parameter, but its use as an index of energy expenditure in children has not been validated previously. The relationship between oxygen uptake and heart rate was found to be linear throughout a wide range of walking speeds for both children with cerebral palsy and normal children. There was no significant difference between the slope or the gamma-intercept of the lines For the two groups. These findings validate the use of heart rate as an index of energy expenditure for normal children and for children with cerebral palsy.

28. Silverman M & Anderson SD (1972): Metabolic cost of treadmill exercise in children. .J.Appl.Physiol 33, 696-698.

Four healthy children, aged 6-11 years, were studied while walking and running on a treadmill at speeds of between 1.6-6.4 km/hr and gradients of 0-20%. Measurements were made at each work level, of minute ventilation, oxygen consumption, and carbon dioxide production. A total of 98 work loads was studied. The results are expressed in terms of multiple linear regression analyses relating oxygen consumption, body weight, treadmill speed, and treadmill gradient. Differences from previously published studies are discussed.

29. Spady DW (1980): Total daily energy expenditure of healthy, free ranging school children. Am.J.Clin.Nutr. 33, 766-775.

This study present estimates of the energy expenditure of a group of school children. Two data sets were used; one based on the direct measurement of oxygen consumption VO2 of 36 children while sitting and used to estimate resting energy expenditure (REE) during the day and one based on the indirect estimation of VO2 by the use of heart rate counters and used to measure energy expenditure while awake (EEA) in 22 children. In all cases night-time energy expenditure was estimated from tables of basal metabolic rate (BMR). These measures permitted estimates to be made of maintenance energy expenditure (MEE) when MEE = (REE x time out of bed) + (BMR x time in bed); total daily energy expenditure (TDEE) when TDEE = (EM x time out of bed) + (BMR x time out of bed); and energy for activity (EAc) when EAc = (TDEE - MEE). Mean TDEE for boys was 2164 kcal/day and for girls 1716 kcal/day; mean MEE for boys was 1503 kcal/day and for girls 1263 kcal/day; mean EAc for boys was 673 kcal/day and for girls was 434 kcal/day. All differences are statistically significant and, with the exception of EAc, remain so when expressed in terms of lean body mass. Estimates of MEE are close to the theoretical estimates for MEE of 105 kcal/kg. The lower TDEE in girls suggests that the recommended dietary allowances for energy should be less than for boys.

30. Spurr GB & Reina JC (1986): Marginal malnutrition in school-aged Colombian boys: body size and energy costs of walking and light load carrying. Hum.Nutr.Clin.Nutr. 40C, 409-419.

The energy expenditure of 93 Colombian boys aged 6-16 years of age and 10 adult American males was measured while walking on a treadmill at 3 mph and 0, 4, 8 and 12 per cent grades with and with backpack loads of 3 (6-8 year), 6 (10-12 year) and 9 kg (14-16 year and adults). The boys were also divided into nutritionally normal and marginally malnourished, based on their weight-for-age and weight-for-height. The primary dependence of energy expenditure on body weight or body weight plus load was not affected by nutritional status, and the results of both adults and control and malnourised children fell on the same straight line at a given treadmill grade, indicating that the undernourished subjects would expend the same energy as nutritionally normal boys and adult subjects for a given load carried. The undernourished boys worked at a higher percentage VO2max than control subjects when load carrying.

31. Spurr GB & Reina JC (1989): Energy expenditure/basal metabolic rate ratios in normal and marginally malnourished Colombian children 6-16 years of age. Eur.J.Clin.Nutr. 43, 515527.

Measurements of basal (BMR) and resting (RMR) metabolic rates, maintenance (MEE) and total daily energy expenditure (TDEE) have been made in Colombian children 6-16 years of age classified as nutritionally normal (boys, n = 129; girls; n = 72) and marginally malnourished (bodys, n = 171; girls, n = 74). TDEE/BMR ratios were calculated for comparison with those suggested by FAO/WHO/UNU (1985) and to provide data for children less than 10 years of age. TDEE was measured in free-living, individually calibrated subjects by the heart-rate method. TDEE/BMR increased significantly with age in boys from 1.60 to 1.84 in control subjects and 1.16 to 1.92 in malnourished boys. There was no significant increase with age in the girls. There were no statistically significant differences between nourished groups but girls had significantly lower values than boys. There was a greater rate of increase in TDEE than BMR with age and girls spent more time in light activities and less in high level activities than boys.

32. Spurr GB, Reina JC & Barac-Nieto M (1986): Marginal malnutrition in school-aged Colombian boys: metabolic rate and estimated daily energy expenditure. Am.J.Clin.Nutr. 44, 113126.

Total daily energy expenditure (TDEE) and energy expenditure in activity (EAc) were estimated in 114 free-ranging, nutritionally normal, and undernourished boys 6-16 yr of age by measuring basal and resting metabolic rates, average daily heart rate while awake, and oxygen consumption and heart rate during exercise on a treadmill. Mean daily heart rates were in the range of exercising heart rates and gave reasonable estimates of TDEE and EAc. TDEE increased with age (p<0.001) and was reduced in undernourished boys (p=0.011). Results indicate that nutritional group differences in TDEE were due to differences in body size. EAc increased with age but did not show significant differences between nutritional groups, indicating that in the marginal malnutrition of school-aged children, reduced growth and associated economy of energy expenditure in locomotion is sufficient physiological adaptation. Peer pressure in school and play activities may interfere with the protective mechanism of reduced activity.

33. Thorstensson A (1986): Effects of moderate external loading on the aerobic demand of submaximal running in men and 10 year-old boys. Eur.J.Appl.Physiol 55, 569-574.

The effects of moderate external loading on the aerobic demand of submaximal running were studied in habitually active adult men (29-37 yrs) and 10 year-old boys. The load was symmetrically placed around the trunk and adjusted to correspond to 10% of body weight. Running was performed on a treadmill at 8, 10 and 11 km.h-1 (2.2, 2.8 and 3.1 m.s-1). A small, but consistent decrease in net oxygen uptake (gross oxygen uptake in ml.kg-1.min-1 minus calculated basal metabolic rate) with load was observed in both groups at all speeds, except for the men at 8 km.h-1. The decrease was larger for the boys and tended to enhance with speed. The boys had a higher net oxygen uptake than the adults at all unladen running velocities, whereas the difference in the loaded condition was significant only at the highest speed. The decrease in net oxygen uptake with load could not be directly correlated with differences in body weight or step frequency. It is hypothesized that a difference in the utilization of muscle elastic energy could underlie part of the age and load dependent changes observed in running economy.

34. Torun B. Chew F & Mendoza RD (1983): Energy costs of activities of preschool children. Nutr.Res. 3, 401-406.

Energy expenditures were measured in 47 children, 17-45 months old, under basal metabolic conditions (mean ± sd: 38 ± 5 cal/kg/min) and while resting supine (44 ± 5), sitting (47 ± 6), walking leisurely on level ground (,71 +- 8), walking rapidly at a grade (98 +- 11), climbing and descending ramps (87 ± 7), climbing stairs (94 ± 8) and riding on a tricycle (73 ± 5). These values are greater than those reported in adults per unit of body weight. Consequently, the energy costs of activities determined in adults should not be applied to preschool children. Our results support the following recommendations to calculate the energy expenditure of preschool children in time-and-motion studies: a) use the energy costs of activities that have been measured in children, whenever available; and b) use 1.2, 2 and 2.5 times the child's basal metabolism, respectively, for sedentary, light and moderately heavy activities, or use the values determined in adults per unit of body weight multiplied by 2 for sedentary activities, and by 1.2 for all other activities.

35. Waters RL, Hislop HJ, Thomas L & Campbell J (1983): Energy cost of walking in normal children and teenagers. Dev.Med. Child Neurol. 25, 184-188.

Oxygen consumption during free level walking was determined in 114 children and teenaged subjects between the ages of 6 and 19 years and compared with a group of 47 normal adults. Subjects were divided into two age groups: children (6-12 years) and adolescents (13-19 years). The mean rate of oxygen uptake for children was significantly greater, 15.3 ml/kg/min, than the value for teenaged subjects, 12.9 ml/kg/mint The oxygen cost to walk a unit distance (meter) was higher in children than adolescent subjects. The mean values averaged 0.22 ml/kg/min and 0.18 ml/kg/min respectively. The data on heart rate paralleled the findings on oxygen consumption. The mean heart rate for children, 114 beats per minute (bpm), was significantly higher than the mean values for adolescent subjects, 97 bpm.

36. Waters RL, Lunsford BR, Perry J & Byrd R (1988): Energy-speed relationship of walking: standard tables. J.Orthop.Res. 6, 215-222.

Department of Surgery, Rancho Los Amigos Medical Center, Downey 90242. The energy expenditure of level walking was measured in 260 normal male and female subjects walking around a 60.5m-circular outdoor track. Subjects were divided into four age groups (children, 612 years; teens; young adults, 20-59 years; and senior adults, 60-80 years). Oxygen consumption was measured with a modified Douglas Bag technique during the fourth and fifth minutes of each trial. Standard tables according to age and sex were derived for the average energy expenditure (rate of oxygen uptake, energy cost per meter, and heart rate) and for the gait characteristics (speed, cadence, stride length) at the subjects' customary slow, normal, and fast walking speeds. Statistical analysis was performed to determine the energy-speed relationship for the different age groups to derive normative tables for the rate of oxygen uptake throughout the range of customary walking velocities.

37. Waxman M & Stunkard AJ (1980): Caloric intake and expenditure of obese boys. J.Pediatr. 96, 187-193.

Caloric intake and expenditure of children in four families were assessed by nonparticipant observations of family dinners and school lunches. In each family there were one obese boy and one nonobese brother whose ages were within two years of each other. For family dinners the nonobese brother served as a control; for school lunches, a nonobese peer served as a control. The obese boys consumed more calories (766 +/- 290) than did their nonobese brothers at dinner (504 +/- 183) and far more (907 +/- 217) than their nonobese peers at lunch (500 +/- 386). The obese boys also ate faster (65.7 +/- 37.0 kcal/minute) than their brothers at dinner (31.7 +/- 13.8 kcal/minute) and far faster (103.5 +/- 40.9 kcal/minute) than their nonobese peers at lunch (46.2 +/- 22.5 kcal/minute). Time-sampled activity assessments showed the obese boys far less active than their controls inside the home, slightly less active outside the home, and equally active at school. When these activity values were converted into energy expenditure by measurement of oxygen consumption, obese boys expended more calories in moving than did their controls; as a result, there was no difference in energy expenditure between obese and nonobese boys at home and greater energy expenditure outside the home and at school. Increased intake, thus, and not decreased caloric output maintained the obesity of these four boys. In this respect, obesity in childhood may differ from obesity in adult life.

Foreign language references

1. Voronina NV (1994): [Daily energy expenditures and energy requirements of pupils at general education schools in the Republic of Uzbekistan]. Gig.Sanit. 20-21.

Evaluation of daily energy expenditures was made on the basis of study of schoolchildren's time budget and their energy expenditures at the main body postures and during various types of activity. The data were used for substantiation of the physiological energy requirements to schoolchildren of different age and sex. Recommendations on the rations for schoolchildren with consideration for age and sex were made

(introductory text...)

1. Bandyopadhyay B & Chattopadhyay H (1980): Energy metabolism in male college students. Indian J.Med.Res. 71, 961-969.

Studies were undertaken on two groups of male college students in West Bengal i.e. 9 athletes and 11 non-athletes to determine their energy metabolic status. It was found that the body fat percentage (8.2 +-1.66) and energy intake (2248 +-114 kcal) were lower in athletes than in the non-athletes (fat percent being 10.1 i-2.21 and energy intake being 2370+-273 kcal), whereas athletes had a comparatively higher body weight (56.0+-7.33 kg) and higher energy expenditure (2326+-194 kcal) than the non-athletes (whose body weight- was 51+-6.73 kg, energy expenditure, 1938+-233 kcal). All non-athlete subjects were in positive caloric balance (+431.63+139.39 kcal) whereas most of the athletes were in a negative caloric balance (77.45+-190.56) in a 7-day study period. Energy expenditure in resting conditions i.e. (Lying, sitting, standing) did not differ significantly between the two groups, but on increasing the work load, athletes showed lower energy expenditure (kcal/kg LBW) than did the non-athletes. In both groups of subjects, the body weight was positively correlated with energy expenditure.

2. Brotherhood JR (1973): Studies on energy expenditure in the antarctic. In: Polar human biology, edited by O.G. Edholm, et al, pp. 182-192. William Heinemann Medical Books Ltd. Great Brittain.

Energy expenditure of men at two British Antarctic Survey bases was measured by indirect calorimetry for both inside and outside activities. The energy cost of most indoor activities was not different from that reported for temperate zones. This suggests that there is little change in basal metabolism in Antarctica. Some individuals worked at unexpectedly high rates at domestic chores. Outside, energy expenditure was high. A number of factors was involved in this increase: (1) Many essential activities involved heavy manual labour. (2) The terrain greatly increased the energy cost of progression, and this was exacerbated by men's requirement to maintain a certain minimum speed. (3) The weight and restricting effect of the clothing worn increased the effort required to perform (1) and (2). (4) With the clothing most often worn, relatively high heat outputs were required to maintain thermal comfort. If the three previous factors did not fulfil this requirement, heat outputs were increased by a) "muscular thermogenesis", but rarely shivering; b) behaviour, in the form of muscular exercise extraneous to the prime activity. (5) On many occasions men were prepared to work at fifty to sixty per cent of their maximum oxygen intakes in order to complete tasks quickly.

3. Brun T. Bleiberg F & Goihman S (1981): Energy expenditure of male farmers in dry and rainy seasons in Upper-Volta. Br.J.Nutr. 45, 67-75.

1. Thirty Mossi male farmers from Upper-Volta were investigated, twenty-three in the dry season (March-April) and sixteen in the rainy season (July-August), eight of them being studied twice. A 48 h time-and-motion study was carried out and the daily energy expenditure was computed. 2. The mean height was 1.70 m and the mean weight 58.5 kg. The averaged percentage of body fat calculated from skinfold thickness was 10. 3. During the dry season the subjects could be classified as very moderately active with an energy output of 10.0 MJ (2410 kcal)/d. By contrast, with an energy expenditure of 14.4 MJ (3460 kcal)/d, they were considered as exceptionally active in July-August when performing the agricultural work. 4. In this study we measured the intensity of physical work in a society where human labour is still the main tool of production. The determination of seasonal variations in energy expenditure may be useful to assess the nutritional requirements in arid zones of West Africa.

4. Cole AH & Ogbe JO (1987): Energy intake, expenditure and pattern of daily activity of Nigerian male students. Br.J.Nutr. 58, 357-367.

Department of Human Nutrition, College of Medicine, University of Ibadan, Nigeria. 1. Twenty apparently healthy and normal Nigerian male students, resident at the University of Ibadan campus, were studied for seven consecutive days to assess their food energy intake and expenditure and pattern of their daily activities. 2. The mean age (years) of the group was 24.0 (SD 3.23, range 20-30), mean height (m) 1.71 (SD 0.06, range 1.61-1.84) and body-weight (kg) was 61.1 (SD 5.01, range 51.0-69.5). 3. The food intake of each subject was obtained by direct weighing and its energy value determined using a ballistic bomb calorimeter. Patterns of daily activities were recorded and the energy costs of representative activities were determined by indirect calorimetry. 4. Activities mainly involved sitting, mean 580 (SD 167, range 394-732) min/d. Sleeping and standing activities took a mean of 445 (SD 112) and 115 (SD 75) min/d respectively. Personal domestic activities took a mean of 94 (SD 40) min/d. 5. The mean energy intake of the group was 11,182 (SD 1970) kJ/d or 183 (SD 32) kJ/kg body-weight per d. This value is lower than the 12.5 MJ/d recommended by the Food and Agriculture Organization (FAO)World Health Organization (WHO) (1973) as the energy requirement for an adult man engaged in moderate activities, but it is higher than the FAO/WHO/United Nations University (UNU) (1985) recommended value of 10.8 MJ/d for a male office clerk (light activity). It is also lower than the recommended energy requirement of 11.6 MJ/d for a subsistence farmer (moderately active work) (FAO/WHO/UNU, 1985). 6. The mean energy expenditure of the male subjects was 9876 (SD 1064, range 7159-12,259) kJ/d and was lower than mean intake. 7. The energy intake and expenditure values indicated that the groups participating in the present study were not physically very active. It is an indication that the Nigerian male students expended less but probably consumed more energy than required. It is suggested for health reasons and for mental fitness that the Nigerian male students might undertake more physical exercise.

5. De Guzman PE, Kalaw JM, Tan RH, Recto RC, Basconcillo RO, Ferrer VT, Tumbokon MS, Yuchingtat GP & Gaurano AL (1974): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. III. Urban jeepney drivers. Philip.J.Nutr. 27, 182-188.

This study is the third of a series on basic and occupational activities. Selection was made based on the distribution of employment by percentage of occupation in the national labor force. The subjects include 10 jeepney drivers plying the San Juan-Mandaluyong route. The same methodology was used as in the previous studies made, (1), (2), wherein one week data on metabolic cost of their basic and occupational activities were measured by indirect calorimetry. The total food intake of each subject was measured daily for seven days by the individual inventory method and data on the time activity pattern was likewise determined.

6. Didier JP, Mourey F. Brondel L, Marcer I, Milan C, Casillas JM, Verges B & Winsland JK (1993): The energetic cost of some daily activities: a comparison in a young and old population. Age Ageing, 22, 90-96.

Groupe d'Etude et de Recherche sur le Handicap, C.H.R.U. de Dijon, France. The energetic costs of some daily activities were compared in two groups, 10 young people (24.3 +/- 2.8 years) and 10 old people (74.4 +/- 2.2 years): rising and sitting back down on a seat, getting up from and Lying down on a bed and getting up from the floor. The oxygen consumption and the time necessary for the activities were measured. The results showed a noteworthy economical energetic procedure when rising and sitting back down on a seat among the older group. The values of the energy expenditure were respectively 3.9 +/- 1.3 car/kg in the older group and 5.8 +/- 1.6 in the younger one with a standard seat (45 cm) and 2.7 +/- 1.2 vs 5.2 +/- 1.5 with a raised seat (60 cm). The activities did not vary significantly in time in the two age groups. This procedure could be understood as an adaptation of the energy expenditure to the reduced aerobic capacity with ageing. Conversely, getting up from and Lying down on the floor or a standard hospital bed involved the same energy expenditure in the older and younger group, but performing these activities took significantly longer for the older people (+60% for getting up from the floor, +33% from the bed). As these activities revealed no economical energetic procedure in the older group, they appeared responsible for a strong factor of dependence. The importance of a learning process particularly for the most usual movements in everyday life is discussed.

7. Dieng K, Lemmonier D, Bleibers F & Brun TA (1980): Differences in the rate of energy expenditure of resting activities between European and African men. Nutr.Rep.lnt. 21, 183-187.

The rates of energy expenditure were measured for two groups of healthy men when lying at rest and standing inactive. 10 West Africans who had been living in France for several years were compared to a control group of 10 French men matched for height and weight. The increase in energy expenditure when changing from lying to standing erect was significantly lower in the Africans. This finding confirms previous results and suggests a racial difference in the rate of energy expenditure when standing inactive.

8. Fellingham GW, Roundy ES, Fisher AG & Bryce GR (1978): Caloric cost of walking and running. Med.Sci.Sport Exerc. 10, 132-136.

Twenty-four young adult male subjects were used to study the relationship between total caloric costs (exercise and recovery costs) incurred and speed of movement over a distance of 1 mile. Caloric costs were determined at walking speeds of 3, 4, and 5 mph and at running speeds of 5, 7, and 9 mph. Energy costs were assessed every 20 sec during the activity and during the recovery until the caloric cost returned to pre-established resting levels. The fitness level of the subjects was considered as a moderating variable. Regression equations to predict caloric cost from body weight, speed of movement, and VO2 max were also developed. Conclusions for the given speeds were: (1) running is more costly than walking, (2) the cost of walking a mile increases with speed of movement, and (3) for running speeds, total caloric cost and VO2 max are inversely related. The independent variables for the regression equation for walking included body weight and speed squared times body weight (R2 = 0.86). The independent variables for the running equation were identical to the ones used in the walking equation with the addition of speed times VO2 max (R2 = 0.62).

9. Kamon E (1973): Rest allowance for stair climbing: a case study. J.Occup.Med. 15, 720-723.

The energy expenditure of eight males who climbed 25 flights of stairs, which totalled 600 footsteps, was measured by using a Kofranyi-Michaelis respirometer. The mean climbing rate was 9.8 ± 2.6 m/min, which equalled a workload of 868 ± 227 kg.m/min, and mean total oxygen uptake was 1595 ± 290 mlO2/min. The mean total and net oxygen uptakes standardized by workload were 1.88 ± 0.20 and 1.53 + - 0.20 ml 02/ kg.m respectively.

10. Kashiwazaki H. Inaoka T. Suzuki T & Kondo Y (1986): Correlations of pedometer readings with energy expenditure in workers during free-living activities. Eur.J.Appl.Physiol 54, 585-590.

In a total of 23 subjects consisting of 10 clerical and 13 assembly workers in a factory, the pedometer readings during a day of free-living activity were analyzed for the relation with energy expenditure as determined by the simultaneously recorded 24-hour heart rate. The 24-hour energy expenditures in the clerical and assembly workers were 9515 kJ (2274 kcal) and 9698 kJ (2318 kcal) respectively. The whole day readings of the pedometer for all the subjects moderately correlated (r=0.438, p<0.05) with the net energy cost (NEC) as determined by subtracting the sleeping metabolic cost from the energy expenditure (clerical workers: r=0.781, p<0.01; assembly workers: r=0.188, p>0.05). The correlation- analysis of the pedometer readings with the NEC in three activity phases in a day (work, commuting and staying at home) showed that the extent of the relationship differed by job types and activity phases. The best correlation was obtained during commuting in both of the job types (clerical workers: r=0.843. p<0.01; assembly workers: r=0.743, p<0.01). During work, a quite strong correlation (r=0.889, p<0.01) was obtained with the clerical workers but not with the assembly workers. No significant correlations were found in the data while the subjects were at home. The capacity of the pedometer to detect the impacts of body movements and the characterisitics of activity is responsible for the differences in correlation. The limitations of the pedometer suggested in the present study must be taken into account if the device is to be used for measuring physical activity. A particular advantage of the device appears to be in its use for a sedentary population without regular strenuous exercise of static contractions.

11. Pandolf KB, Givoni B & Goldman RF (1977): Predicting energy expenditure with loads while standing or walking very slowly. .J.Appl.Physiol 43, 577-581.

Previously a formula was presented to predict metabolic rate (M) for walking and load carrying; it could not be used for walking speeds below 0.7 m.s^-1 (2.5 km.h^-1). In this study, six men each carried backpack loads of 32, 40 and 50 kg while walking at 1.0, 0.8, 0.6, 0.4 and 0.2 m.s^-1 to extend the range of speed down to the stand still level. Metabolic cost of standing with 0-, 10-, 30, or 50-kg backpacks was also investigated in 10 men to evaluate the energy expenditure of load carriage while standing. Energy expenditure increased with external load, both standing and walking. No increased inefficiency occured with very slow walking; M decreased as speed approached zero. The revised predictive formula which now covers standing and the whole range of walking speeds, has the form M= 1.5W + 2.0(W + L)(L/W)² + m(W+L)[1.5V² + 0.35VG] where M= metabolic rate, watts; W = subject weight, kg; L = load carried, kg; V = speed of walking, m.s^-1; G= grade, %; m = terrain factor (m = 1.0 for treadmill). The new formula not only extends the range of application but also allows an adjustment for load as a function of body weight and permits easier calculation of energy expenditure.

12. Pandolf KB, Haisman ME & Goldman RF (1976): Metabolic energy expenditure and terrain coefficients for walking on snow. Ergonomics, 19, 683-690.

Ten male subjects each walked at two speeds, 0.67 and 1.12 m.s^-1 (1.5 and 2.5 mph), on a level treadmill and on a variety of snow depths. Energy expenditure increased linearly with increasing depth of footprint depression and was expressed considering clothed weight, by the regression equation: energy expenditure (W kg^-1 hor km^-1.h^-1)= 1.18 + 0.089 depression (cm). At 45 cm footprint depression as compared to a 0 cm depression, energy expenditure increased by a ratio of approximately 5:1. Although subjects were considered above average in terms of fitness [average VO2max=51.4 ml.kg^-1.min^-1 (n=6)], all terminated walking due to exhaustion at an average footprint depth of 35.0 cm at a walking speed of 1.12 m.s^-1. Practical limits for prolonged snow walking not exceeding approximately 50% V_O2max were developed with 20 cm being the maximal depth at 0.67 m.s^-1, and 10 cm at 1.12 m.s^-1 without snow shoes. At increased footprint depths, limiting factors for snow walking were the increasing lift work, inefficient stooping posture and balancing difficulty.

13. Sheldahl LM, Wilke NA, Dougherty SM, Levandoski SG, Hoffman MD & Tristani FE (1992): Effect of age and coronary artery disease on response to snow shoveling. J.Am.Coll.Cardiol. 20,1111-1117.

Department of Medicine, Veterans Affairs Medical Center, Milwaukee, Wisconsin 53295. Objectives: The objective of this study was to evaluate the effect of age and coronary artery disease on responses to snow shoveling. Background: Little information is available on the hemodynamic and metabolic responses to snow shoveling. Methods: Sixteen men with asymptomatic coronary artery disease and relatively good functional work capacity, 13 older normal men and 12 younger normal men shoveled snow at a self-paced rate. Oxygen consumption, heart rate and blood pressure were determined. In nine men with coronary artery disease left ventricular ejection fraction was evaluated with an ambulatory radionuclide recorder. Results: Oxygen consumption during snow shoveling differed (p < 0.05) among groups; it was lowest (18.5 +/- 0.8 ml/kg per min) in those with coronary artery disease, intermediate (22.2 +/0.9 ml/kg/min) in older normal men and highest (25.6 +/- 1.3 ml/kg/min) in younger normal men. Percent peak treadmill oxygen consumption and heart rate with shoveling in the three groups ranged from 60% to 68% and 75% to 78%, respectively. Left ventricular ejection fraction and frequency of arrhythmias during shoveling were similar to those during treadmill testing. Conclusions: During snow shoveling 1) the rate of energy expenditure selected varied in relation to each man's peak oxygen consumption; 2) older and younger normal men and asymptomatic men with coronary artery disease paced themselves at similar relative work intensities; 3) the work intensity selected represented hard work but was within commonly recommended criteria for aerobic exercise training; and 4) arrhythmias and left ventricular ejection fraction were similar to those associated with dynamic exercise.

14. Tibarewala DN & Ganguli S (1983): Correlation between walking energy expenditure and tachographic gait parameters. J.Med.Eng.Technol. 7, 58-65.

A group of 53 adult men, normal subjects as well as victims of different types of lower-extremities handicaps, took part in tachographic gait studies and measurements of physiological energy expenditure whilst walking at a self-selected pace. The observations were analyzed to explore the relationships between walking energy expenditure and various gait parameters. This analysis allowed the authors to identify some biomechanical indices which can be used for objective evaluations of human performance in locomotion. The investigation reported in this paper is a follow-up to the authors' pilot study which was published in an earlier issue of 'JMET'.

15. Tibarewala DN, Ghosh AK & Ganguli S (1980): An integrated biomechanical-bioenergetic technique for evaluation of human locomotion. J.Med.Eng.Technol. 4, 241-246.

The existing locomotion evaluation techniques are based either on bioenergetic measurements or on biomechanical principles and procedures. While the former basis has been preferred by a few, published literature in this field has contained more information on the latter. No significant work combining both the approaches in a single measurement system is known so far. This paper reports an investigation where an attempt was made to combine both the techniques in relation to a mixed handicapped population composed of 10 test subjects as well as a matching control group. It has been found from the present investigation that the combined application of the above two types of measurements might lead to more useful information about the performance level of the subjects in locomotion. Further, the statistical analysis of the experimental data revealed the existence of a linear correlationship among the parameters used for such performance evaluation. Finally, the study findings have been discussed to indicate how the biomechanical measurements alone can throw sufficient light on the subject's locomotor status.

16. Waters RL, Hislop HJ, Perry J. Thomas L & Campbell J (1983): Comparative cost of walking in young and old adults. J.Orthop.Res. 1, 73-76.

Normative data that summarize the energy requirements and gait characteristics of level outdoor walking were determined in 111 normal subjects between the ages of 20 and 80 years. Subjects were divided into two age groups: young adults (20-59 years) and senior subjects (6080 years). The mean rate of oxygen consumption for young adults and senior subjects did not significantly differ, averaging 11.9 ml/kg-min for both groups. The data on heart rate paralleled the findings on oxygen consumption, averaging 100 and 103 beats/min, respectively. The net oxygen cost per meter walked for senior subjects, 0.16 ml/kg-m, was significantly greater (p<0.0005) than the value for young adults, 0.15 ml/kg-m, due to a decline in the average walking speed. The average gait velocity for senior subjects, 73 m/min, was statistically significantly less (p<0.0005) than the values for the younger adults, 80 m/min.

17. Wyndham CH, Van der Walt WH, van Rensburg AJ, Rogers GG & Strydom NB (1971): The influence of body weight on energy expenditure during walking on a road and on a treadmill. Int. Z. angew. Physiol. einschl.Arbeitsphysiol. 29, 285-292.

Four measurements of oxygen consumption were made on 8 subjects (varying in weight from 54.5-66.1 kg) at each of 3 speeds of walking (3.2, 4.8 and 6.4 km/hr) both on a treadmill and a road. Correlations between weight and oxygen consumption of 0.76-0.96 were significant at the 0.1% level of significance, at all three speeds on both treadmill and road. The relationship between body weight and oxygen consumption is linear and is markedly affected by speed. The slope of the linear regression lines of oxygen consumption on body weight increased hyperbolically with an increased in speed. Mean oxygen consumptions at 3.2 and 4.8 km/hr were significantly higher on the road but not at 6.4 km/hr. Curves of 02 consumption/speed are nonlinear and are markedly affected by body weight; both the intercept on the vertical axis and slope increases linearly with body weight.

18. Yousef MK & Dill DB (1969): Energy expenditure in desert walks: man and burro Equus asinus. .J.Appl.Physiol 27, 681-683.

The economy of energy expenditure of man has been compared with that of burro in grade walking. Two high school students and two female burros were subjects. Student and burro walked side by side with and without loads down and up a 2% grade on a hard-packed desert road. The net oxygen consumption, VO2 in terms of body weight and unit distance is significantly higher in man than in burro walking under similar conditions. A load on the back mounting to 33 or 50% of body weight is carried by the burro nearly as economically as live weight. For man walking downgrade carrying 33% of his body weight costs significantly more per kilogram and per unit distance than his own weight. No significant differences in net VO2 per kilogram and per unit distance was observed in man walking upgrade with and without a load. The energy cost of walking up a 2% grade is about one-half greater than walking downgrade in man and twice as great in burro. The lower cost of walking, the associated economy in food requirement, and tolerance of dehydration explain in part the superiority of the burro for desert transport.

19. Yousef MK, Dill DB & Freeland DV (1972): Energetic cost of grade walking in man and burro, Equus asinus: desert and mountain. .J.Appl.Physiol 33, 337-340.

In the desert at 800 m altitude, P_B 695 mm Hg, men and burros walked on grades from 0 to 17% without a load or with a load equal to 25% of the subject's body weight. Walks on the 17% grade were made also at high altitude, 3800 m, P_B 485 mm Hg. The energetic cost of walking determined by measuring VO2 for each set of conditions was significantly higher in man than burro. The net VO2 per kilogram was the same for load or no load in man and burro on all grades. The advantage of the burro over man walking upgrade was even greater walking downgrade. The energetic cost of climbing a vertical meter was only 9 and 14% higher in man than in burro; however, the cost of walking a horizontal meter required for man twice as much as for the burro. The superior economy of the burro in the desert was also evident at 3800 m altitude. In the burro as in man the cost of walking was unchanged at altitude. The economy of the burro is due to its anatomy and mechanics of walking. The lower cost of walking in the burro is of major importance to his survival in hot deserts.

20. Zarrugh MY & Radcliffe CW (1978): Predicting metabolic cost of level walking. Eur.J.Appl.Physiol 38, 215-223.

Energy expenditure in walking is usually expressed as a function of walking speed. However, this relationship applies only to freely adopted step length-step rate patterns. Both the step length and the step rate must be used to predict the energy expenditure for any combination of step length and step rate. Evidence on seven subjects indicates that the energy demand for such a combination can be determined by conducting two experiments. In the first, the subject is allowed to freely choose his own walking pattern to achieve a set of prescribed speeds. In the second, the speed is kept constant but the subject is forced to adopt a range of prescribed step rates. The results of the two experiments combined yield enough data to make possible the determination of the energy equation of the pattern, encompassing both "free" and "forced" gaits. Results show that the freely chosen step rate requires the feast oxygen consumption at any given speed. Any other forced step rate at the same speed increases the oxygen cost over that required for the "free" step rate.

Foreign language references

1. Wirths W (1979): [Differences in energy expenditure for selected activities under controlled and uncontrolled conditions]. Z.Ernahrungswiss. 18, 250-257.

Notes: Experiments with the Max-Planck respirometer were made to determine the energy expenditure. Four kinds of comparable tests were made under standard conditions and ad libitum individual: walking on solid, level ground with light clothing, in high lace boots (walking-speed 5 km/h), walking with 10 kg resp. 20 kg load on level, solid ground (running-speed 10 km). The energy expenditure under standard conditions is much higher than in the working-elements ad libitum speed and distance. Many persons overestimate their personal energy expenditure which is a reason for a positive energy balance succeeded by overweight.

(introductory text...)

1. Banerjee B. Khew KS & Saha N (1971): A comparative study of energy expenditure in some common daily activities of non-pregnant and pregnant Chinese, Malay and Indian women. J.Obstet.Gynaecol.Br.Commonw. 78, 113-116.

Twenty-five pregnant Chinese women (11 during both second and third trimester and 14 in third trimester only) and 17 non-pregnant Chinese women, 14 third-trimester pregnant and 10 non-pregnant Malay women, and 14 third-trimester pregnant and 10 non-pregnant Indian women were tested for energy cost during rest and under various common daily activities. It was found that the third trimester pregnant women of all three races expended significantly more energy per minute than the respective control groups during rest and in the majority of common daily activities such as sitting and reading, sitting and writing, ironing and washing small clothes. But it was also observed that the percentage increase of expenditure over resting metabolism in every activity was more in non-pregnant controls than in pregnant women indicating that the pregnant women performed tasks in a more relaxed and economical way than the non-pregnant controls. Eleven pregnant Chinese women expended in varying degrees more energy per minute in the third trimester pregnancy than in the second. (The body weights of the present pregnant groups were lower than the European standard.).

2. Banerjee B & Saha N (1981): Energy balance study in pregnant Asian women. Trop.Geogr. Med. 33, 215-218.

Twenty-four pregnant Asian women resident in Singapore were tested for the determination of energy cost of rest and various common daily activities. The average daily energy expenditure was estimated from a diary of activities of seven days. The average daily energy intake was computed from Food Tables on the basis of consumption of measured dressed raw materials of food over seven days in the same period of measurement of energy expenditure. The average daily energy intake and expenditure in this group of pregnant women were found to be 2020 and 1810 kcal (8.5 and 7.6 MJ) giving a balance of +210 kcal (0.9 MJ) per day.

3. Beidleman BA, Puhl JL & De Souza MJ (1995): Energy balance in female distance runners. Am.J.Clin.Nutr. 61, 303-311.

Department of Physical Education, Springfield College, MA. Metabolic efficiency was assessed in ovulatory eumenorrheic female distance runners and untrained control subjects of similar age, body weight, and fat-free mass (FFM). Energy intake (El) was estimated from 3-d dietary records. Energy expenditure (EE) was determined during the same 3-d period from individual heart rate oxygen uptake (HR/VO2) curves during rest and exercise, 24-h HR records, and the thermic effect of meals. The runners and control subjects did not differ in resting metabolic rate statistically adjusted for FFM (kJ/min), the thermic effect of a test meal (kJ/3 h), the energy cost of submaximal physical activity, or El. EE was higher (P = 0.01) in the runners. Reported El was lower than EE in both the runners (P = 0.007) and control subjects (P = 0.006), resulting in energy deficits of -4131 +/- 1185 kJ/d and -1652 +/- 456 kJ/d, respectively. These female runners did not exhibit an enhanced metabolic efficiency compared with the control subjects. It is possible that the energy deficit for both the runners and control subjects was due to both restricted eating and underreporting during the measurement period. Additional studies using longer measurement periods, more sophisticated technology (de, doubly labeled water, more subjects, and subjects of varying menstrual and energy intake status) are needed to truly answer this question.

4. Bleiberg FM, Brun TA, Goihman S & Gouba E (1980): Duration of activities and energy expenditure of female farmers in dry and rainy seasons in Upper-Volta. Br.J.Nutr. 43, 71-82.

1. Fifteen female farmers (aged 18-47 years) from two villages of the Mossi Plateau in Upper-Volta participated in a survey in which their daily activity pattern and their energy expenditure were assessed. Eight of the subjects were investigated twice, in March (dry season) when there is no agricultural activity, and in July-August (rainy season) when heavy physical work is performed: mostly hoeing, weeding and replanting sorghum (Sorghum vulgare) and millet (Pennisetum typhoides). 2. The mean height was 1.57 m and the mean weight 50.6 kg. The average percentage of body fat, calculated from skinfold thickness, was comparable to that of European females but the triceps skinfold was more than 60% below the standard value (Jelliffe, 1969). The type of activities and the period of time spent on each activity changed significantly with the season. The mean energy output rose from 9.7 MJ (2320 kcal) in March to 12.1 MJ (2890 kcal) in July-August for a 55 kg standard weight. 3. In this paper, the extent of both the daily activity pattern of women living in a subsistence agriculture and their energy output is estimated. The results suggest that during the rainy season, the energy requirements of female farmers are much higher than usually estimated.

5. Brun T (1992): The assessment of total energy expenditure of female farmers under field conditions. J.Biosoc.Sci. 24, 325-333.

Institut Agronomique Mediterranéen de Montpellier, France. The paper reviews methods, and their difficulties, in the measurement of the daily energy expenditure of rural women under field conditions in developing countries. Since all methods need to be validated against a reference method which is usually based on indirect calorimetry, examples of the use of this technique are given. The energy costs of most agricultural and daily tasks of rural women in developing countries have been measured. Large intra- and inter-individual variations in the cost of a single activity occur, so repeated measurements are needed to obtain a valid mean energy cost for a specific activity for a homogeneous group of individuals. Much work remains to be done on the assessment of the duration and the intensity of the physical activity of the rural adolescent and adult female population. Studies indicate that the workload of most rural women in developing countries is excessive and frequently associated with acute poverty.

6. Cole AH & Ogungbe RF (1987): Food intake and energy expenditure of Nigerian female students. Br.J.Nutr. 57, 309-318.

Twenty apparently healthy and normal Nigerian female students, resident at the University of Ibadan campus, were studied for seven consecutive days to assess their food energy intake and energy expenditure during sedentary and physical activities. The mean age (years) of the group was 20.05 (SD 3.44, range 16-29), mean height (m) 1.62 (SD 0.07, range 1.47-1.74) and bodyweight (kg) 51.28 (SD 3.21, range 46-58). The food intake of each subject was obtained by direct weighing, and the energy value determined using a ballistic bomb calorimeter. Daily activities were recorded and the energy cost of representative activities was determined by indirect calorimetry. Activities mainly involved sitting, mean (min/d) 354 (SD 84, range 253-475). Personal domestic activities took a mean of 162 (SD 73) min/d. Sleeping took a mean of 451 (SD 62) min/d. The mean energy intake of the group was 8480 (SD 1316) kJ/d or 167 (SD 30.6) kJ/kg body-weight per d. This value is lower than that recommended by the Food and Agriculture Organization/World Health Organization (FAO/WHO) (1973) as the energy requirement for adult women engaged in light activities (9205 kJ/d), but it is higher than the FAO/WHO/United Nations University (UNU) (1985) recommended value of 8326 kJ (1990 kcal)/d for a housewife in an affluent society. It is lower than the recommended intake of 9350 kJ/d for rural women in developing countries (FAO/WHO/UNU, 1985). The mean energy expenditure (kJ/d) of the female subjects was 6865 (SD 214, range 6519-7222). Mean energy expenditure was lower than mean energy intake. The energy intake and expenditure values indicated that the subjects participating in the present study were not physically very active. It is suggested, for health reasons, that they might undertake more physical activity.

7. Dufour DL (1984): The time and energy expenditure of indigenous women horticulturalists in the northwest Amazon. Am.J.Phys.Anthropol. 65, 37-46.

The energy cost of subsistence activities and the daily time and energy budgets of Tatuyo women were assessed as part of a village energy flow study. The Tatuyo are swidden horticulturalists relying on bitter manioc (Manihot esculenta) as a staple crop. Except for the actual felling of new gardens, women are responsible for most of the horticultural work and food preparation. Time budgets were assessed using 24-hour activity diaries. Rates of energy expenditure in typical activities were measured by indirect calorimetry using a Max-Planck respirometer. Daily energy expenditure was calculated using these rates in conjunction with the activity diaries. Rates of energy expenditure in standard activities were moderate and broadly comparable to published values for other populations living in tropical environments. The mean daily energy expenditure was 2, 133 kcal (8.9 MJ). This value is similar to that reported for other subsistence horticulturalists and close to the FAO recommendation for energy intake for moderately active individuals.

8. Htay H. Po L & Mya-Tu M (1978): Habitual physical activity of rural Burmese women. Ergonomics, 21, 239-252.

Habitual physical activity of 16 Burmese women aged 19-24 yrs residing in a rural Burmese village was assessed by the questionnaire method together with the diary method and heart rate measurements. The pattern of their habitual physical activity had a seasonal variation. Their heart rate during transplanting paddy, pounding glutinous paddy and carrying water ranged from 108132, 119-144 and 120-168 beats.min^-1 respectively. Their work intensity expressed as a percentage of their maximal aerobic power varied from 13.04 to 79.47. It was found that the habitual physical activity of these rural women could contribute a positive effect towards their physical performance capacity.

9. Lawrence M, Singh J. Lawrence F & Whitehead RG (1985): The energy cost of common daily activities in African women: increased expenditure in pregnancy? Am.J.Clin.Nutr. 42, 753-763.

A total of 1546 measurements of energy expenditure on 142 nonpregnant, pregnant, or lactating Gambian village women were performed by open-circuit indirect calorimetry. Of the 47 common daily activities measured, only 7 would be classified as moderate according to internationally accepted standards, the remainder being light (ie requiring less than 3.5 kcal/min). This was unexpected since many of the tasks, judged subjectively, appeared quite demanding. Furthermore there was no increase towards the end of pregnancy in the energy cost of a range of activities requiring 1-5 kcal/min and involving a variety of body movements, despite the substantial weight gains observed. Only for walking was there the expected increase in energy expenditure. Although in the past it has been assumed that the heavier pregnant women would require additional energy for activity, no special allowance for this is included in current dietary recommendations. The present results indicate that, for women from the developing world, no allowance is necessary. The finding that most activities were light is also of relevance to total energy requirements in this community.

10. Nagy LE & King JO (1983): Energy expenditure of pregnant women at rest or walking self-paced. Am.J.Clin.Nutr. 38, 369-376.

Energy expenditure during rest and self-paced walking was determined from early to late pregnancy either longitudinally or in a cross-section of women. The cross-sectional study was done with 16 women confined to a metabolic unit: six nonpregnant (NP), six early pregnant (EP 10 to 20 wk gestation), and four late pregnant (LP 30 to 40 wk gestation). In the longitudinal study, five of the six EP subjects from the cross-sectional study were studied at 5-wk intervals until parturition. Basal metabolic rate, measured by open circuit, indirect calorimetry, and expressed as kcal/min, was 13% greater (p c 0.05) in EP compared to NP and was 28% greater (p < 0.05) in LP compared to EP. Resting metabolism increased during gestation in the EP group from a value of 1.01 kcal/min fat 15 to 25 wk to 1.15 kcal/min at 35 to 40 wk. When energy expenditure during rest is expressed as kcal/kg body weight/h, there were no significant differences due to stage of pregnancy. The time required for the women to walk 400 m at their own pace was measured. The pace of the LP women was 20% slower (p < 0.05) than the EP women. But when the EP women were studied at 35 and 40 wk gestation their pace was only 4.5% slower than that at 15 to 25 wk. These data suggest that individual behavioral differences have a greater effect on pace than stage of gestation. A decrease in pace reduced the rate of energy expenditure per kilogram body weight for walking 400 m. But, body weight, rather than pace, was the major determinant of total energy expenditure for the walk (p < 0.05). It is apparent from these data that body weight is the major determinant of energy expenditure during rest and self-paced weight bearing activity in pregnancy.

11. Okeke EC, Etta EN & Nnanyelugo DO (1995): Energy expenditure on traditional activities by Nigerian women, monitored by Oxylog. Food.Nutr.Bull. 16, 67-71.

This study was undertaken to evaluate the energy expended by Nigerian women in preparing two traditional foods from cowpeas, akara (fried paste) and moimoi (steamed paste), both by traditional methods and using processed pea flour. Data were collected using a questionnaire, and energy expenditure was monitored with an oxylog apparatus. In making akara by the traditional method, a mean of 44.4 +/- 1.5 kcal (185.5 +/-7.4 kJ) of energy was spent per kilogram of peas processed, as against 25.7 +/- 0.6 kcal (107.4 +/- 2.8 kJ) using pea flour. For moimoi, 27.6 +/0 0.8 kcal (11.5 +/0 3.3 kJ)/kg was spent by the traditional method, against 14.6 +/- 1.5 kcal (61.2 +/- 6.3 kJ)/kg using flour. While the overall energy cost of the methods using pea flour was significantly lower than the traditional methods, the energy cost of aerating the paste for making akara was almost 2.5 times as high as the traditional method. This higher energy intensity is due to slower solubilization of proteins in flour required to form and sustain foam. Longer soaking of the flour paste could reduce the energy required for aeration.

12. Panter-Brick C (1993): Seasonality of energy expenditure during pregnancy and lactation for rural Nepali women. Am.J.Clin.Nutr. 57, 620-628.

Department of Anthropology, Durham University, UK. Total energy expenditure (TEE) was estimated for 19 nonpregnant, nonlactating (NPNL) and 24 pregnant (P) or lactating (L) women from 3601 h of minute-by-minute observation and 168 measurements of the energy cost of activities. NPNL women significantly increased subsistence activity and TEE from 9.9 MJ [1.89 x basal metabolic rate (BMR)] in the winter to 10.5 MJ (2.01 x BMR) in the monsoon season. There were differences between NPNL,P, and L women in the winter, but not in the spring or monsoon season when all individuals sustained very heavy physical activity. High TEE values resulted from spending very long hours in tasks that, although appearing physically demanding to the casual observer, were characterized by light or moderate energy cost. The study highlights the importance of seasonal constraints on women's work, which prevent P and L women from significantly curtailing physical activity during the monsoon season, and which effectively limit the scope of behavioral mechanisms for saving energy and reducing TEE.

13. Schutz Y. Lechtig A & Bradfield RB (1980): Energy expenditures and food intakes of lactating women in Guatemala. Am.J.Clin.Nutr. 33, 892-902.

Total energy expenditures and intakes were simultaneously assessed in 18 free-ranging lactating women (10 months postpartum) and compared to six similarly-sized, nonlactating, nonpregnant but multiparous women living in the same rural villages in the Guatemalan highlands. Energy intakes were estimated by the 24-hr recall method for each of 4 consecutive days. Energy expenditures were determined for 2 days by monitoring heart rate throughout the day and relating heart rate to oxygen consumption by individually-determined regression lines. The mean energy intake for the 4 consecutive days was estimated to be 1929 +/- 360 kcal/day (39.2 kcal/kg per day) for the lactating group; and 1876 +/- 404 kcal/day (38.3 kcal/kg per day) for the nonlactating group. The 2-day mean energy expenditures were estimated to be 2007 +/292 kcal/day for the lactating women (41.8 kcal/kg per day) and 1966 +/- 382 kcal/day for the lactating women (40.1 kcal/kg per day). The way of life of both groups was judged "moderately active" by 1973 FAO/WHO classifications. Most of the lactating women had been losing weight progressively during the past 6 months. Over the 10-week period prior to our measurements, the mean weight loss was more than 10 times greater in the lactating group (-369 g/month) (P < 0.01) than in the nonlactating group (-35 g/month) (ns). The high correlation (r = 0.87) between weight loss and the reduction in the sum of the three skinfolds suggested adipose tissue loss. There were no significant differences between the two groups in terms of daily energy intake, daily energy expenditure, the energy cost of specific activities throughout the day. The slope of the heart, ate/oxygen consumption regressions suggest adequate cardiorespiratory fitness. This study suggests that the energy cost of lactation was met to a greater extent by fat loss than by either increased energy intake, reduced energy expenditure, or both.

14. Tin-May-Than (1988): Energy expenditure, duration of activities, and physical work capacities of Burmese women weavers. Food.Nutr.Bull. 10, 48-50.

This study asseses the daily energy expenditure of Burmese women weavers and concludes that, although the total energy cost of their work is considerable because of the many hours involved, it is not sufficiently intense either for substantial muscular development or for cardiovascular fitness. The weavers would not be able to tolerate work demanding high energy expenditure.

15. Torun B. McGuire J & Mendoza RD (1982): Energy cost of activities and tasks of women from a rural region of Guatemala. Nutr.Res. 2, 127-136.

The energy cost of various domestic and agricultural activities were measured by indirect calorimetry in 56 women, 16-49 years old, from a small rural village. Mean energy expenditures (kcal/kg/min) were 0.021-0.035 for fourteen activities ("light occupations"), 0.038 - 0.064 for thirteen ("moderately active" occupations) and 0.072 - 0.089 for four ("very active" occupations). There were no differences per kg of weight between pregnant, lactating and non-pregnant, nonlactating women. The results were compared with other studies and weighted averages were calculated. The values reported can be used in combination with measurements of time to estimate energy expenditure in time-motion studies.

16. van Raaij JMA, Schonk CM, Vermaat-Miedema SH, Peek MEM & Hautvast JGAJ (1990): Energy cost of physical activity throughout pregnancy and the first year postpartum in Dutch women with sedentary lifestyles. Am.J.Clin.Nutr. 52, 234-239.

Department of Human Nutrition, Agricultural University, Wageningen, The Netherlands. Basal metabolic rate (BMR), activity pattern, and energy costs of some daily activities were measured in 25 Dutch women throughout pregnancy and the first year postpartum. Physical activity index (PAI), which refers to daily energy expenditure expressed as a multiple of BMR, was calculated from activity-pattern data and activity costs. Mean PAls (+/-SD) throughout pregnancy, during the first 6 mo postpartum, and at 1 y postpartum were 1.48 +/- 0.08, 1.49 +/- 0.07, and 1.53 +/0.10 x BMR, respectively. Because measured BMR at 1 y postpartum was 1440 +/- 168 kcal/d, costs for physical activity in pregnancy and the first 6 mo postpartum were, respectively, approximately 70 and approximately 50 kcal/d lower than at 1 y postpartum. For women with sedentary lifestyles the energy saved during pregnancy and lactation because of decreased physical activity and decreased costs of activities will be limited.

Foreign language references

1. Seidell JC, Melchers M, Deurenberg P & van Staveren WA (1984): [Energiebesteding van een groep jonge volwassen vrouwen]. Voeding, 45, 46-49.

Notes: In 20 young adult women, aged 29 +- 2.8 years, resting metabolic rate (RMR) and the energy cost of some household activities were measured. The best fit was found in the correlation between RMR and body weight (W): RMR (kJ/min) = 2.80 + 0.023 W. r = 0.75. The net energy cost of a standardized activity (treadmill, 3.9 km/in) could best be predicted by body weight: E(kJ/min) = 3.04 + 0.12 W. r = 0.75. The energy cost of moderate household activities was less than could be expected from the literature, but the energy cost of strenuous activities was higher than values mentioned in the literature. However, this made little difference to total daily energy expenditure/day as seen in a comparable group of women.

4.1.3 Men & women

1. Ashworth (1968): An investigation of very low calorie intakes reported in Jamaica. Br.J.Nutr. 22, 341-355.

1. A previous dietary survey has reported some very low calorie intakes in a farming community in rural Jamaica. Subsequently, ten subjects were specially selected on the basis of being very poor and underfed and individual dietary surveys were carried out in their homes for 7 days. 2. The accuracy of the dietary surveys was tested in a metabolic ward by feeding the subjects with the same meals as were recorded in their homes. Body-weight, calorie and nitrogen intakes, and urinary and faecal N outputs were measured. 3. Basal metabolic rates and the calorie expenditure during sleep were measured to investigate whether any metabloic adaptations to the low calorie intakes had occured. The calorie cost of performing a standard step-test was measured and compared with that of well-fed control subjects to find out if there were differences in physical efficiency. 4. Nine of the subjects were found to be thinner than the average person of the same age and sex in their district, and were considerably thinner than the average American. 5. Five of the dietary surveys were thought to have given a correct picture of the normal dietary pattern. The remaining five surveys were unsatisfactory. 6. In the five correct surveys, the calorie intakes were 61, 69, 72, 78 and 98 % of the FAO recommended requirements. 7. No clear-cut evidence of an adaptive change in basal metabolic rate was found. 8. Few calories were available for physical exertion and there was an apparent increase in the physical efficiency of work.

2. Banerjee B & Saha N (1970): Energy cost of some common daily activities of active tropical male and female subjects. .J.Appl.Physiol 29, 200-203.

Energy cost of some common daily activities of 30 male cadets and 10 policewomen of Singapore police force was measured by a Max Planck respirometer and Lloyd's gas analysis apparatus, both before and after lunch. Energy expenditure (in kcal/min) of the subjects was found to be lower than Western figures, which can be accounted for by lower body weight of the subjects of the present series. And the values (in kcal/min), respectively, for male and female subjects were: lying rest-1.12 and 0.95; sitting rest-1.31 and 1.10; sitting-reading-1.23 and 1.08; sitting-writing-1.28 and 1.03; standing-1.44 and 1.23; walking-3.34 and 2.67; running-6.27 and 5.52; postexcercise recovery-3.07 and 2.68; marching-4.73 and 3.55. Their average clothed body weights being 59.7 and 55.5 kg, respectively. Highest energy expenditure was observed in running, followed closely by marching, for both male and female subjects. There was no significant difference in energy cost between sitting and sitting-reading and sitting-writing, neither was there any pre-and post-lunch difference in any of the activities. Average daily energy intake and output were 3,036 and 3,028 kcal for male and 1,742 and 1,752 kcal for female subjects with protein intake of 105 and 72 9 respectively.

3. Banerjee B & Saha N (1972): Effect of temperature variation in a climatic chamber on energy cost of rest and work. Environ.Res. 5, 241-247.

Energy expenditures with some common daily activities of 10 male and 10 female medical students were measured at the room temperature of 29°, and at 18° and 38° in a climatic chamber. The increased resting metabolic rate and energy cost for different activities in hot and cold temperatures were found to be not significantly higher than that for room temperature except in a few categories. The energy cost for all the activities was found to be lower than that reported in western figures.

4. Banerjee B & Saha N (1972): Resting metabolic rate and energy cost of some common daily activities of trained and untrained tropical people. J.Sports Med. 12, 111-116.

The energy cost during rest and some common daily activities was measured in trained and untrained Chinese men and women of age range 18-25 years. Both trained men and women expended more energy per kg lean body mass than their untrained counterparts, during lying rest, sitting, sitting & reading, sitting and writing, standing, walking and slow speed running. During postexercise recovery untrained people expended more energy than the trained people.

5. Bleiberg F. Brun TA, Goihman S & Lippman D (1981): Food intake and energy expenditure of male and female farmers from Upper-Volta. Br.J.Nutr. 45, 505-515.

1. The energy balance of eleven male and fourteen female adult farmers was measured for 6 d after the harvest, in December-January. Their energy intake was recorded by weighing their food consumption and their energy expenditure was determined using indirect calorimetry. 2. Bodyweight, expressed as percentage of expected weight-for-height was 91 and 86% of the Interdepartmental Committee on Nutrition for National Development (1963) standard for women and men respectively. 3. The staple foods were sorghum (Sorghum vulgare) and millet (Pennisetum typhoides); carbohydrates, fat and protein supplied approximately 80, 13 and 12% of the total energy of the diet respectively. 4. In the male group, the mean energy intake (9.0 MJ (2148 kcal)) was in good agreement with the average energy output (8.91 MJ (2130 kcal)). By contrast, in the female group, the mean energy expenditure (8.11 MJ (1941 kcal)) exceeded the mean energy intake (6.3 MJ (1515 kcal)) and the deficit was statistically significant. 5. This study allows an evaluation of the adequacy of food intake for subjects living in a particular hostile environment, by using their actual energy output instead of current standard values. The energy deficit found for female farmers whose energy intake was similar to that reported In other developing countries emphasizes the need for a better understanding of the regulation of energy balance in such conditions.

6. Blessey RL, Hislop HJ, Waters RL & Antonelli D (1976): Metabolic energy cost of unrestrained walking. Phys. Ther. 56, 1019-1024.

Physiologic factors of metabolic energy cost as well as selected mechanical characteristics of gait are described in a group of 40 presumably normal men and women between the ages of 20 and 60 years. Special emphasis was placed on unrestrained (free cadence) walking to provide a reliable baseline for comparison to persons with physical gait impairments. Velocity of walking was the most important factor in determining oxygen uptake and was independent of age or sex. An empirical equation was established relating oxygen uptake to the speed of walking. The average velocity for men in unrestrained walking trials was 89 meters per minute; for women 74 meters per minute. These differences were related to the greater stride length in men. The average cadence selected by both sexes was 116 steps per minute. None of these factors was age dependent. Of the physiologic measures only systolic blood pressure was age dependent predictably rising with age. The mean heart rate was 103 beats per minute and did not vary significantly between men and women. The mean respiratory rate was 19 per minute; the mean respiratory quotient, 0.85, neither being age or sex dependent. Oxygen uptake values averaged 12.95 ml/kg-min for the population studied and again were neither age nor sex dependent.

7. De Guzman PE, Cabrera JP, Yuchingtat GP, Abanto ZU & Gaurano AL (1984): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups 11. Laguna rice farmers. Philip.J.Nutr. 37, 163-174.

The total energy expenditure and dietary intake of nine male and nine female rice farmers in Barrio Pansol in Pila, Laguna, an area of the Philippines where rice is the main agricultural crop, were determined for one week each during different periods in the agricultural diary. These were land preparation, planting, weeding and harvesting, and also the off-farming period. The energy costs of specific activities carried out during these periods were measured via indirect calorimetry. Total energy expenditure was calculated using the factorial method of Durnin of Brockmore using these values and additional values from published tables. A seven day diary was used to calculate energy intakes. There were significant differences in the energy expenditure of both male and female farmers between the different periods but not in energy intakes. Intake was significantly less than expenditure during all periods except the off-farming. The mean daily energy expenditure of the male farmers during the year was approximated to be 2977 kcal or 12,456 kJ and mean daily intake was 2708 kcal or 11,330 kJ. The females had a mean energy expenditure of 2181 kcal or 9125 kJ and mean intake of 1807 kcal or 7560 kJ. Although energy intake was less than energy expenditure for both male and female farmers, the difference was statistically significant only in the female farmers. When compared to the recommended dietary allowances, the mean energy intake of the male farmers may be considered adequate because it represented 107% of the RDA. The mean energy intake of the female farmers was lower and represented only 97% of the recommended level. These differences, however, were not statistically significant. With reference to the FAO/WHO recommendation, both male and female farmers can be classified as moderately active. A study of the pattern and variation in the work activities throughout the year showed that the male farmers were found to engage in non-farming activities for approximately 44% of the year while the rest of the time was spent performing agricultural activities. The female farmers engaged in non-farming activities for a longer period (64%) and spent only 36% of the year doing farming activities. Differences in energy expenditure and intake and also body weight between the different periods of farm activity were mostly not statistically significant. The results of this study indicate that energy balance in these subjects was achieved over a long period of time, rather than on a daily or even monthly basis.

8. De Guzman PE, Cabrera JP, Basconcillo RO, Gaurano AL, Yuchingtat GP, Tan RM, Kalaw JM & Recto RC (1978): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. V. Clerk-Typist. Philip.J.Nutr. 31, 147-156.

The energy expenditure, dietary intake and activity patterns of ten male and ten female clerks and typists, a major occupational group in The Philippines, were examined. The energy cost of common occupational activities was measured using a Max Planck respirometer. Subjects kept an activity diary and total energy expenditure was calculated by the factorial method of Durnin and Brockway using the original measurements of energy costs and data from published tables. Values obtained for the metabolic cost for the basic activities expressed in calories per kilogram per minute indicated differences in mean energy costs between sexes when sitting and standing. The F-ratio obtained was not significant in testing the null hypothesis that walking has the same energy cost for male and females. Mean values obtained for the daily protein, fat, carbohydrate, and total energy intake of each subject more or less approximated the percentage calorie distribution in the eight regions surveyed in the Philippines. F-tests to compare the means of total energy intake and expenditure for the two sexes indicated no significant differences in the total energy intakes of the two groups. However, there was evidence to conclude that the male group had higher total energy expenditure than the female group. It was also observed that when weight was considered as a normalizing factor, the differences in expenditure difference between the two sexes were no longer significant. The clerks and typists studied based on the joint FAO/WHO recommendations on energy expenditure can be classified as lightly active to very lightly active.

9. De Guzman PE, Dominguez SR, Kalaw JM, Buning MN, Basconcillo RO & Santos VF (1974): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. II. Markina shoemakers and housewives. Philip.J.Nutr. 27, 21-30.

This study is the second of a series on occupational activities of Filipinos. The first study was made on rice farmers (1). The subjects for the study include 10 shoemakers and 10 housewives in the municipality of Markina, province of Rizal, where the shoemaking industry is concentrated. The same methodology was used as in the previous study wherein one week data on the energy expenditure of each subject was measured by indirect calorimetry while performing their usual daily activities. Time spent and the mean daily food intake of the subjects were likewise measured during the same period.

10. De Guzman PE, Recto RC, Cabrera JP, Basconcillo RO, Gaurano AL, Yuchingtat GP & Abanto ZU (1979): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups VI. Textile mill workers. Philip.J.Nutr. 3, 134-148.

Twenty-five male and fourteen female textile workers were studied to determine their pattern of daily activity, dietary intake, and energy expenditure. The energy costs of basic and occupational activities were measured by indirect calorimetry. Values obtained for sitting, standing and walking among the males did not differ significantly from those of the females. Univariate analysis was used to compare these values with data previously collected on other occupational groups. No significant F-ratio was obtained indicating that the sampled subjects from the different groups have comparable energy expenditure for these basic activities. Analysis of the differences between men and women in energy costs of different activity types in the textile production process showed that men expended significantly more energy than women in spinning and weaving. The mean daily energy expenditure for the males was 2,494 kcal and for the females, 2,024 kcal. These values were significantly high compared with their mean daily energy intake of 2,339 kcal and 1,510 kcal, respectively. The textile mill workers can be classified as lightly active to moderately active with reference to the FAD/WHO recommendations.

11. Edholm OG, Humphrey S. Lourie JA, Tredre BE & Brotherhood J (1973): VI. Energy expenditure and climatic exposure of Yemenite and Kurdish Jews in Israel. Philos.Trans.R.Soc.Lond.Biol. 266, 127-140.

The daily energy expenditure of Yemenite and Kurdish Jews has been assessed in summer and winter. The majority of the male subjects were engaged in farming; the women were mainly housewives. A timed activity survey was carried out on all subjects. The differences between summer and winter were, in general, small and the time spent by the men in different activities averaged for the two seasons were, for the Yemenite Jews, 7.69 h lying, 7.16 h sitting, 7.6 h working. The Kurdish Jews spent 8.44 h Lying, 6.4 h sitting and 7.4 h working. Energy expenditure was computed from the timed activity survey and measurements of oxygen consumption in a number of tasks. The energy expenditure of the men in the summer was 3050 kcal (12760kJ) per day for both the Yemenite and Kurdish Jews. In the winter, the Yemenite Jews expended 3000 kcal (12560kJ) and the Kurdish Jews 3110 kcal (13020 kJ) per day. The Yemenite Jewish women expended 2280 kcal (9550kJ) per day in the summer and 2400 kcal (10040 kJ) per day in the winter, and the Kurdish Jewish women expended 2250 (9420 kJ) per day in the summer and 2390 kcal (10000kJ) per day in the winter. Integrated heart rates were recorded in the two seasons, during the night and during the day. The night rates were significantly lower in the summer than in the winter. The average night rates (beats/min) in summer and winter respectively were: Kurdish Jews, men 56.3 and 60.9, women 63.0 and 70.6; Yemenite Jews, men 60.4 and 65.6, women 66.6 and 70.5. The time spent out of doors in the daylight hours was 348 min/day in the summer and 347 min/day in the winter for the Yemenite Jewish men. The Kurdish Jewish men spent 401 min/day out of doors in the summer and 342 min/day out of doors in the winter. The Yemenite Jewish women were out of doors for 205 min/day in the summer and 243 rein/day in the winter. The corresponding figures for the Kurdish Jewish women were 203 and 81 min/day.

12. Edmundson WC & Edmundson SA (1989): Energy balance, nutrient intake and discretionary activity in a South Indian village. Ecol.Food Nutr. 22, 253-265.

The energy balance and discretionary activity of eight male and eight female South Indian farmers was carefully measured For four days in 1983. The women, who were small and had low energy intakes, expended far more time on work than the males. Height and weight for male subjects averaged 161.0 cm and 48.2 kg. The women were 148.8 cm tall and weighed only 36.9 kg. Women were able to perform the 15 work tasks at lower cost than men primarily because they were smaller. In males the mean energy intake was 9.83 MJ (2350 kcal). The females' mean energy intake was 7.73 MJ (1852 kcal). The average energy intake was 7.73 MJ (1852 kcal). The average energy intake per unit mass was equal for both sexes at 22 kJ (50 kcal) per kg. Women allocated more time to economically productive work (46.2% or 11.1 hours versus 33.9% or 8.1 hours). There was no significant correlation between an individual's energy intake and time spent working (r=-.24). There was no association between intake and energy expended on economically productive tasks (r=.02). Both social and physiological processes enable women and others on a low plane of nutrition to maintain a high level of productivity.

13. Florentino RF, De Guzman PE & Garcia LP (1966): The energy cost of basic activities in some Filipinos. Philip.J.Nutr. 19, 258-271.

The energy cost of Lying, sitting and standing at ease and walking at own pace were determined by indirect calorimetry in 10 male and 10 female Filipino young adults. Lying involved 0.87 cal/min and 0.78 cal/min; sitting 0.96 cal/min and 0.85 cal/min; standing 1.12 cal/min and 0.98 cal/min; and walking, 2.15 cal/min at 1.5 mi/hr and 1.88 cal/min at 1.4 mi/hr in the males and females, respectively. Coefficients of variation ranged from 13%-21%. The energy costs of these activities in the males, when expressed in terms of body weight, surface area or metabolic size, did not differ significantly from those in females. Metabolic size was found to be better correlated with energy cost than either body weight or surface area. When body size is taken into account, the rate of energy expenditure for these basic activities in the Filipino subjects were found to be very similar to foreign figures. This supports the conclusion that the total daily caloric expenditure of Filipinos as a whole differs from that of other groups of people mainly because of body size and type and duration of physical activities performed, rather than race or climate.

14. Garby L, Kurzer MS, Lammert O & Nielsen E (1987): Energy expenditure during sleep in men and women: evaporative and sensible heat losses. Hum.Nutr.Clin.Nutr. 41C, 225-233.

Evaporative and sensible heat losses were measured during sleep in 38 male and 21 female subjects in a direct whole-body calorimeter (24 m3). The subjects were all apparently healthy, had a mean body weight of 66 kg and had spent the preceding day in the calorimeter performing different fixed physical activity programmes. Heat losses were measured continuously between 11.30 p.m. and 6.30 a.m. The average (+/- s.e.m.) rate of total heat loss during the 7h of sleep was 90.6 +/- 1.21 and 74.4 +/- 1.22 watts for men and women respectively. The total heat loss during basal resting conditions immediately following sleep was 83.8 +/-1.5 and 69.2 +/- 1.6 watts, respectively. Heat production during basal resting conditions, as measured by indirect calorimetry about 1 h after awakening on the morning of the preceding day, was found to be 85.6 +/- 1.3 and 71.2 +/- 1.1 watts, respectively. The increase in heat loss during sleep above that of basal resting conditions could largely be attributed to an increase in the evaporative heat loss. The heat loss fell during the night by about 14 per cent in women and about 30 per cent in men, approaching basal resting values in the last hour of sleep. Heat production during sleep was calculated for the male subjects by correcting the heat loss data for the published decreases in rectal temperature during the night and was found to be on average 9 per cent lower than the heat loss. The present data, as well as previously reported data, suggest that the energy expenditure of sleep is 0.95 X BMR rather than 1.0 X BMR as reported in the recent (FAO/WHO/UNU Expert consultation (1985).

15. Jing L & Wenyu Y (1991): The energy expenditure and nutritional status of college students. I The energy cost and the total energy expenditure per day. Biomed.Environ.Sci. 4, 295-303.

The energy cost of major activities was determined in healthy students. Among the 606 medical students, 319 were males and 287 were females. Their ages ranged from 18 to 24 years. Douglas' method was used to measure energy cost of each of a total of 42 activities, as well as that of the basal metabolic rates (BMR), resting metabolic rates (RMR) and the total energy expenditure per day under normal situations. The average RMR of male and female subjects were 0.669 +- 0.033 and 0.656 +- 0.030 kcal/sq.m/min respectively. The total energy expenditure per day of male students were 2706 kcal, and 2373 kcal for female students. The energy cost of single activities can be used as the basal data in studies of energy metabolism.

16. Kurzer MS (1987): Effect of activity on the energy cost of sitting in men and women: implications for calorimeter studies. Hum.Nutr.Clin.Nutr. 41C, 403-407.

It is important that activities be carefully standardized during whole-body human calorimetry studies because differences in physical activity in the calorimeter between subjects may mask true metabolic differences or result in false differences. The purpose of this study was to quantify the extra heat losses that may occur due to small body movements, which are not standardized while sitting in whole-body calorimetry activity programmes. Energy expenditure was measured in 17 men and women while sitting passively and sitting actively. The subjects sat in a chair in a whole-body calorimeter for a total of 4 hours. During the first hour the subjects sat and were allowed to read and listen to the radio while adapting to the calorimeter. During the second and fourth hour the subjects sat passively, and during the third hour they performed standardized arm and leg stretches every 6 minutes while remaining seated. A 31% increase in total heat loss during active sitting was found. It is thus important that the manner of sitting be controlled in studies looking for an effect smaller than 15%.

17. Montgomery E & Johnson A (1977): Machiguenga energy expenditure. Ecol.Food Nutr. 6, 97-105.

This article presents the results of a study of energy expended at typical activities and on average days, by adult women and men of a hunter-gatherer-horticulturalist population in south eastern Peru. Marked differences between the sexes in patterns of energy use are presented. The men tended to work at higher rates of energy expenditure than did the women. On the average day, representatives of all activities in an annual cycle, the women expended about 8.0 MJ (1925 Cals) whereas the men expended about 13.3 (3200 Cals). Seasonal analysis reveals an even greater contrast during the wet months. Relations between the Machiguenga and their upper Amazonian rain forest environment are considered in accounting for the observed patterns of energy expenditure. Factors such as differences in uses of technology, work settings, and population composition are related to the findings.

18. Morgan NG, Ferro-Luzzi A & Durnin JVGA (1974): The energy and nutrient intake and the energy expenditure of 204 New Guinean adults. Philos. Trans.R.Soc.Lond.Biol. 268, 309-348.

Two village populations, Kaul in a coastal region and Lufa in a highland region, were each studied for 9-10 months. Measurements of food intake and total daily energy expenditure were made on individual subjects, 51 men and 69 women in Kaul and 43 men and 41 women in Lufa. Each individual was investigated during a period of 5-7 consecutive days. The way of life for all the people was moderately active - more so in the highlands - since they were subsistence farmers cultivating their own gardens for food. The mean daily energy intakes were 8.12 MJ (1940 kcal) for the Kaul men, 10.55 MJ (2520 kcal) for the Lufa men, 5.95 MJ (1420 kcal) for the Kaul women and 8.81 MJ (2105 kcal) for the Lufa women. There were almost no differences in the energy intakes of the non-pregnant non-lactating, the pregnant and the lactating women in each village. The intakes of protein were low, providing 6.7, 6.0, 6.5 and 7.2% of the energy value of the diets of the Kaul men and women and the Lufa men and women respectively. Fat provided only about 10% of the energy in the highland diet and 17% in the coastal diet. Age and body mass showed surprising relationships with energy intake. Although most of the energy and protein in the diets came from the staple vegetable (taro in Kaul and sweet potato in Lufa), this was less so than in previous studies. A total of 1160 measurements of energy expenditure were made on various activities in the individual people and mean values are given for these activities. The pattern of daily energy expenditure is also shown. Lying, sitting and standing accounted for about 70% of the total day and 60% of the total energy expenditure. Walking occupied about 10% of the 24h and between 20 and 27% of the energy output. Some of the results of food intake, particularly on the women in the coastal region, are very difficult to explain on currently accepted grounds.

19. Panter-Brick C (1992): The energy cost of common tasks in rural Nepal: levels of energy expenditure compatible with sustained physical activity. Eur.J.Appl.Physiol 64, 477-484.

Department of Anthropology, Durham University, UK. Three hundred and six measurements of energy expenditure by indirect calorimetry of sitting at rest and self-paced activity were made on 41 men, 48 women and 6 adolescents in a mountain village of Nepal. Except for walking and carrying uphill, measured activities fell within the range of values for light to moderate effort, despite appearing physically demanding. Villagers tended to reduce travel speed when carrying heavy loads (54-102% of body mass on various inclines), averaging a moderate level of energy expenditure which could be sustained throughout the day. Such moderately demanding work was also assumed by pregnant, lactating women and young adolescents. Pregnant women worked more slowly at some tasks, but did not differentiate themselves from their non-pregnant, non-lactating counterparts for travel on the mountain side.

20. Saha N. Tan PY & Banerjee B (1985): Energy balance study in Singapore medical students. Ann.Nutr.Metab. 29, 216-222.

Energy cost of rest and various common daily activities was measured in 7 male and 16 female medical students by using a Max-Planck respirometer and a Lloyd's gas analysis apparatus. The average weight of male and female subjects during the course of the study was 67.3 +/14.2 and 51.2 +/- 5.1 kg, respectively. The average energy expenditure per day was estimated from a diary of activities for a period of 7 days. The average daily intake of energy was computed from food tables and based on weighed amounts of raw materials of food consumed over the same 7-day period when energy expenditure was determined. The average energy expenditure of rest and different activities was found to be significantly lower than the figures published for western subjects. The daily energy intake and expenditure were 2,138 +/- 217 kcal (9.0 +/-0.9 MJ) and 1,894 +/- 168 kcal (8.0 +/- 0.7 MJ), respectively, in male medical students, giving a positive balance of 244 kcal (1.0 MJ). The values of the same in female medical students were 1,711 +/- 292 kcal (7.2 +/- 1.2 MJ) and 1,474 +/- 211 kcal (6.2 +/- 0.9 MJ) with a balance of 237 kcal (1.0 MJ).

21. Waters RL, Hislop HJ, Perry J. Thomas L & Campbell J (1983): Comparative cost of walking in young and old adults. J.Orthop.Res. 1, 73-76.

Normative data that summarize the energy requirements and gait characteristics of level outdoor walking were determined in 111 normal subjects between the ages of 20 and 80 years. Subjects were divided into two age groups: young adults (20-59 years) and senior subjects (6080 years). The mean rate of oxygen consumption for young adults and senior subjects did not significantly differ, averaging 11.9 ml/kg-min for both groups. The data on heart rate paralleled the findings on oxygen consumption, averaging 100 and 103 beats/min, respectively. The net oxygen cost per meter walked for senior subjects, 0.16 ml/kg-m, was significantly greater (p < 0.0005) than the value for young adults, 0.15 ml/kg-m, due to a decline in the average walking speed. The average gait velocity for senior subjects, 73 m/min, was statistically significantly less (p < 0.0005) than the values for the younger adults, 80 m/mint

22. Waters RL, Lunsford BR, Perry J & Byrd R (1988): Energy-speed relationship of walking: standard tables. J.Orthop.Res. 6, 215-222.

Department of Surgery, Rancho Los Amigos Medical Center, Downey 90242. The energy expenditure of level walking was measured in 260 normal male and female subjects walking around a 60.5m-circular outdoor track. Subjects were divided into four age groups (children, 612 years; teens; young adults, 20-59 years; and senior adults, 60-80 years). Oxygen consumption was measured with a modified Douglas Bag technique during the fourth and fifth minutes of each trial. Standard tables according to age and sex were derived for the average energy expenditure (rate of oxygen uptake, energy cost per meter, and heart rate) and for the gait characteristics (speed, cadence, stride length) at the subjects' customary slow, normal, and fast walking speeds. Statistical analysis was performed to determine the energy-speed relationship for the different age groups to derive normative tables for the rate of oxygen uptake throughout the range of customary walking velocities.

23. Webb P (1981): Energy expenditure and fat-free mass in men and women. Am.J.Clin.Nutr. 34, 1816-1826.

Energy expenditure was measured by direct calorimetry in 15 men and women aged 22 to 55. There were fifty-nine 24-h measurements under quiet, not basal, conditions of sedentary activity with 8 h of sleep at night, regular meals, and food intake adjusted to match individual expenditures. Fat-free mass was calculated from body density determined from underwater weight. Energy expenditure over a whole day and night varied directly with fat-free mass, with a correlation coefficient, r, of 0.95 (p less than 0.001); neither age nor sex affected the relationship. During sleep alone, energy expenditure also correlated highly with fat-free mass (r = 0.93). Energy expenditure also correlated with body surface area (r = 0.90), but men and women showed regression lines with different slopes. Metabolism from indirect calorimetry, measured simultaneously, correlated nearly as well with fat-free mass and surface area but showed more variability. The close correlation between 24-h energy expenditure and fat-free mass contrasts favorably with the imprecise prediction of basal metabolic rate according to age, sex, and surface area, and supports the idea that active tissue mass determines daily energy expenditure.

(introductory text...)

1. Almero EM, De Guzman PE, Cabrera JP, Yuchingtat GP, Piguing MC, Gaurano JP, Caguiat JO, Zolanzo FG & Alina FT (1984): A study of metabolic costs of activities and dietary intake of some construction workers. Philip.J.Nutr. 37, 49-56.

This is the tenth of a series of studies on the energy expenditure of occupational groups. Twenty-five subjects were selected from a total of 37 construction workers employed by a contractor building a residential house in San Juan, Metro Manila. They were screened based on normal body weight (+- 15%, the standard weight for height for Filipinos) and the absence of cardiovascular, respiratory as well as thyroid and other metabolic disorders. Time and motion studies were conducted by actual observation of the activities of each subject for three consecutive days. Food intake of the subjects for the same days was weighed or recalled by the respondents. Gas samples were collected as they performed their occupational activities and subsequently analyzed for oxygen content. A table of the metabolic costs of their activities is presented. The mean total energy intake (2731 +- 402 kcal) nearly balanced the mean total energy expenditure (2834 +- 457 kcal). According to the FAD/WHO recommendations, the activities of the construction workers studied could be classified as moderately active to very active.

2. Astrand I, Fugelli P. Karlsson CG, Rodahl K & Vokac Z (1973): Energy output and work stress in coastal fishing. Scand.J.Clin.Lab.Invest. 31, 105-113.

Energy expenditure in 14 fishermen engaged in fishing was determined by direct measurement of oxygen uptake and by indirect assessment based on continuous recording of the heart rate. Urinary excretion of catecholamines was assayed as an index of stress response. The average energy expenditure during all activities on board for the whole day amounted to the equivalent of about 1 litre O2 uptake per minute, corresponding to about 39% of the fishermen's maximal aerobic power, with peaks up to 80%. On the average, about a tenfold increase in epinephrine and a fourfold increase in norepinephrine excretion were observed during work as compared to resting night values.

3. Barnes RM (1973): Physical energy expenditure in long-haul cabin crew. Aerosp.Med. 44, 783785.

A study of the physical energy expenditure of BOAC's cabin crew was carried out as a part of a workload survey. It was not considered possible to place a repirometer on a crew member during a normal commercial flight on aesthetic grounds and an indirect method of measurement was, therefore, devised. Due to the variety of duties cabin staff carry out it was necessary to analyse their working day and break it down into a number of defined tasks. Volunteers were asked to carry out these tasks in the training mock-up whilst wearing a Max Plack respirometer. From the results obtained, the ,subjects'' energy expenditure per minute was calculated. Experiments were carried out to show that the figures obtained were equally applicable at cabin altitudes. By means of time and motion studies and questioning the cabin crew an "average working day" and a "maximum working day" were built up. The energy expenditure was then estimated. This was compared with that of other working groups. It was concluded that the physical energy expenditure of cabin crew was within acceptable limits.

4. Bell DG & Wright GR (1979): Energy expenditure and work stress of divers performing a variety of underwater work tasks. Ergonomics, 22, 345-356.

The energy expenditure of forty-four students training to become commercial divers was determined for a variety of underwater work tasks. Energy expenditures were predicted from heart rate produced during the work task. Heart rates ranged from 80 beats min-1 (resting) to 151 beats min-1 (working). Depending on the labelling of the task as arm or leg work, the mean heart rate generated was substituted into one of two equations used for predicting oxygen consumption. These equations, derived from leg and arm work performed on a bicycle ergometer in the laboratory, were: O2 (litres min^-1) = -1.55+0.024*heart rate (beats min^-1) for leg work and O2 (litres min^-1) = -1.61+0.032*heart rate(beats min^-1 - 0.066*10^-3*heart rate (beats min^-1) arm work. The energy expenditure for the various tasks, calculated from oxygen consumption, ranged from 30% to 79% of the maximum determined for three divers. The implications for diver safety are discussed.

5. Bobo M, Bethea NJ, Ayoub MM & Intaranont K (1983): Energy expenditure and aerobic fitness of male low seam coal miners. Hum.Factors. 25, 43-48.

The physiological responses of male low seam coal miners were measured both above and below ground to ascertain the characteristics and task demands of mining low coal in very restricted surroundings (seam height 1.2 m or lower). Aerobic capacity was estimated from measurements of expired air and heart rate taken while subjects rode a stationary bicycle. Total ventilation (as measured by a respirometer) was used to assess underground energy expenditure and oxygen consumption. Results indicate that low seam coal miners do not have higher maximum oxygen consumption values than nonmining populations. Individual task analyses for oxygen uptake and kilocalorie are discussed.

6. Brotherhood JR (1973): Studies on energy expenditure in the antarctic. In: Polar human biology, edited by O.G. Edholm, et al, pp. 182-192. William Heinemann Medical Books Ltd. Great Brittain.

Energy expenditure of men at two British Antarctic Survey bases was measured by indirect calorimetry for both inside and outside activities. The energy cost of most indoor activities was not different from that reported for temperate zones. This suggests that there is little change in basal metabolism in Antarctica. Some individuals worked at unexpectedly high rates at domestic chores. Outside, energy expenditure was high. A number of factors was involved in this increase: (1) Many essential activities involved heavy manual labour. (2) The terrain greatly increased the energy cost of progression, and this was exacerbated by men's requirement to maintain a certain minimum speed. (3) The weight and restricting effect of the clothing worn increased the effort required to perform (1) and (2). (4) With the clothing most often worn, relatively high heat outputs were required to maintain thermal comfort. If the three previous factors did not fulfil this requirement, heat outputs were increased by a) "muscular thermogenesis", but rarely shivering; b) behaviour, in the form of muscular exercise extraneous to the prime activity. (5) On many occasions men were prepared to work at fifty to sixty per cent of their maximum oxygen intakes in order to complete tasks quickly.

7. Brun T. Bleiberg F & Goihman S (1981): Energy expenditure of male farmers in dry and rainy seasons in Upper-Volta. Br.J.Nutr. 45, 67-75.

1. Thirty Mossi male farmers from Upper-Volta were investigated, twenty-three in the dry season (March-April) and sixteen in the rainy season (July-August), eight of them being studied twice. A 48 h time-and-motion study was carried out and the daily energy expenditure was computed. 2. The mean height was 1.70 m and the mean weight 58.5 kg. The averaged percentage of body fat calculated from skinfold thickness was 10. 3. During the dry season the subjects could be classified as very moderately active with an energy output of 10.0 MJ (2410 kcal)/d. By contrast, with an energy expenditure of 14.4 MJ (3460 kcal)d, they were considered as exceptionally active in July-August when performing the agricultural work. 4. In this study we measured the intensity of physical work in a society where human labour is still the main tool of production. The determination of seasonal variations in energy expenditure may be useful to assess the nutritional requirements in arid zones of West Africa.

B. Brun TA, Geissler CA, Mirbagheri MS, Hormozdiary H. Bastani MSJ & Hedayat H (1979): The energy expenditure of Iranian agricultural workers. Am.J.Clin.Nutr. 32, 2154-2161.

The energy cost of agricultural and standard activities and the daily energy expenditure of male agricultural workers were measure during different seasons in Iranian villages to assess the validity of past and present Food and Agricultural Organization recommended energy allowances for that population. Studies included low income farmers in a village representative of those around the central desert where harvesting takes place under conditions of extreme summer heat. Measurements were also made during the Moslem fasting period when no food may be eaten between dawn and dusk. Energy cost of typical activity was measured by indirect calorimetry using the Max-Planck respirometer and daily energy expenditure was assessed using these figures combined with a diary of activities throughout the 24-h period. Results of individual activity values are compared with other published figures. Comparison of daily energy expenditure of fasting subjects and nonfasting after Ramzan showed no significant difference. No significant difference was found between values of standardized activities at high summer temperatures and moderate temperatures. Mean values of daily energy expenditure during winter when activity is low are around 2600 kcal/day and for other seasons of high activity 3400 kcal/day. These figures suggest that past and present Food and Agricultural Organization standards are low for this population.

9. Capelli C, Donatelli C, Moia C, Valier C, Rosa G & di Prampero PE (1990): Energy cost and efficiency of sculling a Venetian gondola. Eur.J.Appl.Physiol 60, 175-178.

Istituto di Biologia, Facolta di Medicina e Chirurgia, Udine, Italy. Oxygen uptake was measured on four male subjects during sculling gondolas at constant speeds from approximately 1 to approximately 3 m.s-1. The number of scullers on board in the different trials was one, two or four. Tractional water resistance (drag, D, N) was also measured in the same range of speeds. Energy cost of locomotion per unit of distance (C, J.m-1), as calculated from the ratio of 02 uptake above resting to, increased with v according to a power function (C = 155.2.v1.67; r = 0.88). Also D could be described as a power function of the speed: D = 12.3.v2.21; r = 0.94). The overall efficiency of motion, as obtained from the ratio of D to C, increased with speed from 9.2% at 1.41 m.s-1 to 14.5% at 3.0,B m.s-1. It is concluded that, in spite of this relatively low efficiency of motion, the gondola is a very economic means. Indeed, at low speeds (approximately 1 m.s-1), the absolute amount of energy for propelling a gondola is the same as that for waking on the level at the same speed for a subject of 70 kg body mass.

10. Consolazio CF (1971): Energy expenditure studies in military populations using Kofranyi-Michaelis respirometers. Am.J.Clin.Nutr. 24, 1431-1437.

The Kofranyi-Michaelis (K-M) respirometer is now being used extensively in measuring the physical activities of military personnel. This paper describes the use of this meter, the problems of calibration and diffusion of the respiratory gases, the newer modifications for simplification of the measurements, and the total errors that are anticipated in its use. Data from a number of studies which measured the energy cost of various routine physical activities of military personnel are presented. The results are expressed as kilocalories/minute. [not original abstract].

11. Costa G. Berti F & Betta A (1989): Physiological cost of apple-farming activities. Appl.Ergon. 20, 281-286.

Seventeen agricultural male workers, aged between 21 and 56 years, were investigated in the field during six different job-activites of apple-farming: pruning, weeding, hand and mechanical spraying, mowing and picking. Pulmonary ventilation and oxygen consumption were recorded for short periods by Oxylog, while heart rate was monitored for more than 24 hours by Holter's method. The farmer also rated the work intensity according to Borg's RPE scale. Pulmonary ventilation ranged on average between 13 and 30 I/min and oxygen consumption between 500 and 1300 ml/min, with a relative aerobic cost between 15 and 40%, in the different work activities. Heart rate varied on average between 80 and 94 beats/min with a relative cardiac cost between 20 and 30%. The physiological criteria (oxygen uptake and cardiac response) and the subjective rating of fatigue gave a substantially similar evaluation of the work strain, 'moderate-heavy' for mowing, weeding and picking, 'moderate' for pruning and hand spraying, 'light' for mechanical spraying of pesticides. On the whole, apple-farming can be evaluated as 'moderate' intensity, thanks to the mechanisation implemented in reducing the work-load and work-time of many job activities.

12. Das SK & Saha H (1966): Climbing efficiency with different modes of load carriage. Indian J.Med.Res. 54, 866-871.

1. Three different modes of load carriage were studied during level walking and during climbing 10 and 20 per cent gradients respectively with a speed of 3.22 km/hr. The load carried was 27 kg and it was (i) suspended from the shoulder, (ii) suspended from the forehead, and (iii) carried on the head. 2. The values of O2 ml/kg/min, and energy expenditure kcal/min, indicated that the performance of the subjects during level walking was more or less the same irrespective of the mode of carriage. 3. During grade walking, however, the load carried on the head required a larger amount of energy expenditure than when it was carried suspended either from the shoulder or from the forehead. 4. A load could be carried with equal efficiency, suspended from the shoulder or from the forehead under conditions of these experiments.

13. Datta SR, Chatterjee BB & Roy BN (1973): The relationship between energy expenditure and pulse rates with body weight and the load carried during load carrying on the level. Ergonomics, 16, 507-513.

In a study of load carriage on the head on the level, high degrees of correlation were obtained with the gross weights transported (viz. body weight and given load) and the energy expenditures, r=0.91. Their relationship fits the equation, E(kcal/minute)=0.0943(body weight+load carried)-2.183. The gross weight transported was also found to have an equally high correlation with the peak heart rates observed (r=0.88) and the regression equation, PHR=1.2552 (body weight+load carried)+24.87, mathematically describes the relationship of the two latter variables. These equations can conveniently be utilized for field studies of load carrying in many underdeveloped countries where the common mode of load carriage is identical with that investigated here and the average body weight of the subjects similar to that of the manual workers in this country, viz. around 50 kg.

14. Datta SR, Chatterjee BB & Roy BN (1975): Maximum permissible weight to be carried on the head by a male worker from eastern India. .J.Appl.Physiol 38, 132-135.

Six healthy adult male Indian workers whose physical characteristics resembled those of the average worker from eastern India, were required to carry compact loads of 20, 30, 40, and 50 kg at a speed of 5 km/in on separate days. From observations on energy expenditures, of peak pulse rates, and of the patterns of recovery pulse rates, it was decided that for the average eastern Indian male worker the permissible weight of a compact load for manual carriage on a hard, level terrain should not ordinarily be more than 30 kg.

15. Datta SR, Chatterjee BB & Roy BN (1978): The energy cost of rickshaw pulling. Ergonomics, 21, 879-886.

Rickshaw pulling is an occupation prevalent in some parts of India and in certain other countries. the energy expenditure of the task under different operational conditions has been studied. The ergonomic features of the rickshaw have also been discussed.

16. Datta SR, Chatterjee BB & Roy BN (1983): The energy cost of pulling handcarts ('thela'). Ergonomics, 26, 461-464.

Transporting loads using an indigenous handcart (the 'thela') is a common occupation in many parts of India. Energy expenditure and heart rates under different operational conditions show that pulling a loaded cart represents very heavy work. The Ergonomics features of the handcart are also discussed.

17. Datta SR & Ramanathan NL (1970): Ergonomical studies on load carrying up staircases. Part III - effect of the mode of carrying. Indian J.Med.Res. 58, 1764-1770.

Nine subjects participated in this study. Three modes of carrying, namely, on the head, by hands and in a rucksack, were employed for transporting 15 and 30 kg up the staircase. The rucksack method is relatively more economical in energy expenditure in general. For 30 kg load, this method results in significantly lower energy costs. Carrying by hand is inconvenient and uneconomical. The heart rate is not consistently different for the three modes, though on the average the rucksack mode results in the lowest strain. Since stairclimbing is usually a short duration task, the advantage due to the mode of carrying is not as appreciable as in the case of work of long duration like walking or climbing hills.

18. Datta SR & Ramanathan NL (1970): Ergonomical studies on load carrying up staircases. Part I - effect of external load on energy cost and heart rate. Indian J.Med.Res. 58, 1629-1636.

Six subjects climbed stairs at a fixed rate with external loads ranging from 0-30 kg on the head. The energy expenditure and peak heart rate were observed to increase with external load. A highly significant linear relation between the load and physiological parameters was derived. The gross mechanical efficiency was computed and found to be fairly constant for the subjects and loads studied. It is concluded that an upper limit of 30 kg should be recommended for load carrying up stairs by a sing e average Indian.

19. Datta SR & Ramanathan NL (1970): Ergonomical studies on load carrying up staircases. Part II - effect of the rate of ascent. Indian J.Med.Res. 58, 1637-1642.

Six subjects climbed stairs with a 15 kg load on the head at four rates of ascent, one of which involved interruption on each floor. The energy expenditure and peak heart rate were found to increase with the rate of ascent. The energy expenditure during recovery was also found to follow this trend. The gross mechanical efficiency increased with the rate of ascent due to the increasing amount of anaerobic work involved in this case. The actual efficiency, which takes into account the higher recovery energy expenditure was found to be fairly constant for all subjects at 12.02%. It appears that a speed of climbing of 60 to 80 steps per minute is the optimum to be recommended.

20. Datta SR & Ramanathan NL (1971): Ergonomic comparison of seven modes of carrying loads on the horizontal plane. Ergonomics, 14, 269-278.

A comparative study of seven modes of carrying an identical load on the level ground was conducted on seven normal, healthy volunteers. The methods of carrying were: Head, Rucksack, Double Pack, Rice Bag, Sherpa, Yoke and Hands. The volunteers marched with 30 kg at the rate of 5 km/hr and the minute ventilation, oxygen consumption and pulse rate were recorded during the steady state of work and a 5 min recovery period after work. Analysis of variance on the data established a significant (p<0.01) difference in the values of the physiological parameters of energy cost, cardiac rate and pulmonary ventilation due to a change in the mode of carrying. The Double Pack mode was ergonomically the best mode, followed closely by the Head mode. Carrying by Hands was the worst method and the others were intermediate as far as physiological economy is concerned. The merits and demerits of these modes of carrying loads are discussed briefly.

21. Davies CT, Brotherhood JR, Collins KJ, Dore C, Imms F. Musgrove J. Weiner JS, Amin MA, Ismail HM, El Karim M, Omer AH & Sukkar MY (1976): Energy expenditure and physiological performance of Sudanese cane cutters. Br.J.Ind.Med. 33, 181-186.

The thermal and exercise tolerances of 165 Sudanese cane cutters were measured in the laboratory and related to work performance and productivity in the cane fields. The results showed that the amount of cane cut per minute in the field was significantly correlated with changes in body weight (r = +0-53) during the third hour of work, aerobic energy expenditure (r = + 0-43), and cardiac frequency during work. These variables in turn were associated with predicted maximal power output VO2 max) measured in the laboratory. The average energy expenditure during cane cutting was 1.66 +/- 0.33 1/min-1 (34.9 kJ/min-1) which represents approximately 60% of the workers predicted VO2 max. This rate of energy expenditure was sustained in the cane fields for at least three hours without significant pauses for rest. The sweat losses measured in 32 cane cutters during the two and three hours of work averaged 637 +/- 221 and 770 +/- 282 g/h-1 respectively, while the mean urine temperature immediately on cessation of effort was 37.74 +/- 0.46 degrees C. Despite the additional environmental heat load of the tropics, it would seem that cane cutters performing a self-paced task demanding heavy physical effort are able to sustain work levels well in excess of those recommended for most European factory workers without obvious signs of fatigue or heat stress.

22. Davis HL, Faulkner TW & Miller Cl (1971): Evaluating work performance. Am.J.Clin.Nutr. 24, 1171-1179.

Reasons and methods for measuring the physiological demands of industrial jobs are discussed. Data on the energy costs of a range of industrial tasks collected via indirect calorimetry are presented. The need for a range of techniques in the assessment of work physiology to address the wide range of demands placed on different types of worker is stressed. [not original abstract].

23. De Guzman PE, Dominguez SR, Kalaw JM, Buning MN, Basconcillo RO & Santos VF (1974): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. ll. Markina shoemakers and housewives. Philip.J.Nutr. 27, 21-30.

This study is the second of a series on occupational activities of Filipinos. The first study was made on rice farmers (1). The subjects for the study include 10 shoemakers and 10 housewives in the municipality of Markina, province of Rizal where the shoemaking industry is concentrated. The same methodology was used as in the previous study wherein one week data on the energy expenditure of each subject was measured by indirect calorimetry while performing their usual daily activities. Time spent and the mean daily food intake of the subjects were likewise measured during the same period.

24. De Guzman PE, Kalaw JM, Tan RH, Recto RC, Basconcillo RO, Ferrer VT, Tumbokon MS, Yuchingtat GP & Gaurano AL (1974): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. III. Urban jeepney drivers. Philip.J.Nutr. 27, 182-188.

This study is the third of a series on basic and occupational activities. Selection was made based on the distribution of employment by percentage of occupation in the national labor force. The subjects include 10 jeepney drivers plying the San Juan-Mandaluyong route. The same methodology was used as in the previous studies made, (1), (2), wherein one week data on metabolic cost of their basic and occupational activities were measured by indirect calorimetry. The total food intake of each subject was measured daily for seven days by the individual inventory method and data on the time activity pattern was likewise determined.

25. Edholm OG, Adam JM, Healy MJ, Wolff HS, Goldsmith R & Best TW (1970): Food intake and energy expenditure of army recruits. Br.J.Nutr. 24, 1091-1107.

1. The food intake of 64 infant recruits was measured at six centres during 3 weeks of initial training. The daily energy expenditure was measured in 35 of these men. 2. The mean daily consumption of the 64 subjects provided them with 3850 kcal (16110 kJ); the energy expenditure of the 35 subjects averaged 3750 kcal (15690 kJ). 3. Serial auto- and cross-correlations of intake and expenditure were very small and there was no significant relationship between food intake and energy expenditure on the same day. 4. The intakes and expenditures of different subjects at the same centre were independent. 5. There was a significant relationship between intake and expenditure for the whole period of the survey when results for all subjects were included. In three centres the correlation was high, +0.788 (P<0.001), but was only +0.083 (P<0.5) in the remaining three centres. 6. There was a positive but not significant correlation between body-weight and the average food intake of 6 d. 7. There was a negative correlation between body-weight and calorie balance. 8. Weight change and calorie balance over 1 week were related, the correlation averaging 0.40. There was a correlation of 0.32 between daily weight changes and calorie balance. A rather small amount of variation in calorie balance can be explained by contemporary changes in weight.

26. el Karim MA, Sharief N & Ballal MA (1987): Effects of exposure to cotton dust on energy expenditure in the textile industry. Int.Arch.Occup.Environ.Health, 59, 347-353.

An assessment of energy expenditure has been made in 50 male textile workers and 30 male office cleaners. There was a statistically significant difference (P less than 0.001) in energy expenditure between textile workers and office cleaners amounting to 12 to 16%. While 33.3% of the textile group complained of chest disorders, none of the cleaners had such a complaint. FEV1 and FVC values of the textile workers were significantly lower (P less than 0.01) compared to those of the controls. There were no differences in body weight, lean body mass and socioeconomic conditions of the two groups, however the textile workers were younger and taller than the unexposed group. Exposure to cotton dust and respiratory and ventilatory impairments are suspected of causing a reduction in the energy expenditure of the textile workers.

27. Fariduddin KM & Rahaman MM (1976): Study of energy expenditure and food intake of some working class people of Bangladesh: part -II. Bangladesh Med.Res.Counc.Bull. 2, 27-30.

Data on energy expenditure during some occupational activities (ploughing, digging, earthcutting and brick-breaking) and the dietary intake of a group of cultivators are presented and the data discussed.

28. Fariduddin KM, Rahman MM & Ahsanullah AB (1975): Study of energy expenditure and food intake of some working class people of Bangladesh. Bangladesh Med.Res.Counc.Bull. 1, 24-23.

No information is available on energy expenditure and dietary intake of Bangladesh population carried out simultaneously. As a preliminary step in this direction, forty volunteers mostly from the low socio-economic groups were subjected to these studies for a 3-4 day period. Indirect calorimetric method was used for the measurement of oxygen consumption and energy expenditure. Actual weighing of food articles were carried out before consumption and values calculated from standard tables. It was found that values obtained during rest like sitting and lying including basal metabolic rate (BMR) fell within values reported in the literature. Resting energy expenditure, however, tended to rise in the later part of the day and the degree of physical activity carried out by the subjects. Rickshaw pedalling required 6.66 kcal/min to be expended without passenger and 7.84 kcal/min with two passengers. Cart pulling required 5.5 kcal/min without load compared to 6.08 kcal/min with a load of 350 kg. The small difference was obviously due to a reduction in the speed of cart pulling. This was, however, not true with rickshaw pedallers. Dietary intake showed that all the subjects were getting a low protein and low fat diet and that carbohydrates were the main source (over 80%) of calories. The doctors were the only group receiving some animal protein and the cart pullers eating almost none. The number of calories taken were consistent with their activities. One rickshaw pedaller had an unusually high intake of over 6000 calories daily.

29. Haisman MF (1972): Energy expenditure of soldiers in a warm humid climate. Br.J.Nutr. 27, 375-381.

1. Energy expenditure determinations have been made on 32 soldiers newly arrived in the warm humid climate of the southern Malaya. Ergometer cycling was investigated as well as everyday activities such as lying, sitting, riding in a truck, ablutions, building a jungle camp and walking with loads over four different routes. 2. The inter-individual variation in the gross energy expenditure (kcal/min and kJ/min) of each activity has been compared with the variation in energy expenditure standardized for body-weight, surface area and lean body mass. Standardization for body size did not consistently or effectively reduce the coefficients of variation of energy expenditure. 3. The gross energy expenditure of most activities was significantly correlated with body-weight, surface area or lean body mass but correlation coefficients were not of a high order, suggesting that less than 41% of the inter-individual variation in energy expenditure accounted for by variation in body size. 4. The energy expenditure of walking at various speeds over both firm and uneven terrain was related to the square of the walking speed and the total weight of the man and his equipment (correlation coefficients 0.89-0.92, P<0.001).

30. Haisman MF & Goldman RF (1974): Effect of terrain on the energy cost of walking with back loads and handcart loads. .J.Appl.Physiol 36, 545-548.

Previous work established that moving heavy loads by cart on a smooth surface required a lower energy cost than the same load on the back. However, the effect of uneven terrain on this energy cost differential had not to the researchers knowledge been studied systematically. Eight young soldiers carried a 20-kg back load (additional to clothing and respirometer) or pulled a handcart weighing 20, 60, or 100 kg, at two speeds (0.89 or 1.34 m.s^-1) on three terrains (blacktop road, dirt road or grassland) in a randomized factorial design. Energy cost was measured three times during each 30-min walk. The results indicated that although on a smooth surface the 100-kg cart is no more costly than a 20-kg backpack, on both uneven terrains only the 20-kg cart was equivalent to a 20-kg back load. Nonetheless, the energy cost of moving the 100-kg cart over these uneven terrains, at these speeds, was within acceptable physiological limits for these subjects, although this would probably not be the case with more difficult such as soft sand or heavy brush.

31. Haisman MF, Winsmann FR & Goldman RF (1972): Energy cost of pushing loaded handcarts. .J.Appl.Physiol 33,181-183.

Seven male volunteers, mean age 21 years, pushed four types of handcarts at 1.56 m/s, on a level treadmill and on a outdoor asphalt circuit. The carts (A, four-wheel; B, C, D, two-wheel) had the following wheel diameters: A, rear 30 cm, front 15 cm; B. 50 cm; C, 40 cm; D, 35 cm. Each cart was loaded to achieve a total weight of 50 kg. Three measurements of energy expenditure were made during each 30-min walk. The mean value for all carts for the treadmill walks was 511 +- 52 (SD) W. 45 W. Cart A was found to require the lowest energy expenditure, 478 +- 37 W. and D the highest, 555 +- 41 W.

32. Horvath SM, Colwell MO & Raven PB (1972): Energy requirements of aluminum smelter workers. Arch.Environ.Health, 25, 323-328.

Studies on maximum work capacity were made on eight male volunteer aluminum smelter workers prior to and immediately after a normal eight-hour work shift. No differences were found between morning and afternoon values for maximum work load, maximum work time, energy output, heart rate, expired ventilatory volumes, or concentrations of blood lactates. The metabolic energy expenditures (oxygen uptake) of various representative tasks undertaken by the workers were also determined. Marked differences in energy expenditures for specific operations were observed not only between individuals, but also for the same job. An estimate of the total energy output for each man per working shift gave a value of 1,515 kilocalories. It was apparent that under the conditions of both work and thermal load the men were capable of maintaining cardiorespiratory efficiency.

33. Immink MD, Blake CC, Viteri FE, Flores R & Torun B (1986): Energy supplementation and productivity of Guatemalan sugar-cane cutters: a longitudinal approach. Arch.Latinoam.Nutr. 36, 247-259.

A long-term energy supplementation program was carried out to determine its effect on the productivity of agricultural workers in Guatemala. The program provided, free of charge, a low-energy (24 kcal) and a high-energy (350 kcal) bottled, orange-flavored soft drink to two groups of long-term resident sugar-cane cutters who worked on the same plantation, located in the Pacific Coast. Previous to, and periodically thereafter during implementation of the program, data relative to energy intake and anthropometry were collected. Through data obtained from payroll lists, a longitudinal series of average productivity (tons of sugar cane cut and loaded per day) covering 48 weeks of pre-supplementation, 90 weeks of supplementation and 21 weeks post-supplementation, was constructed. Control of the supplement consumption was observed daily. Random assignment of workers to the high-energy supplement (HES) and the low-energy (LES) groups was not possible. Prior to supplementation both groups presented the same characteristics in terms of age, energy intake level, weight, height, tricipital adiposity and daily productivity. Little variation was found throughout the time the supplement was consumed by the HES Group. Energy intake of workers increased significantly in absolute terms in relation to the LES Group, except towards the end of the 28 months' supplementation period. Energy balance was maintained by workers throughout the study period. A time series of the difference in mean productivity of the two supplement groups (Yt) was modeled using the ARIMA techniques. No auto-regressive term was present in the Yt series. The ARIMA (0,0,1) model was fitted and expanded with different intervention components. None of the estimated parameters of the intervention components were statistically significant. It was therefore concluded that no abrupt, or gradual and sustained energy supplementation effect on productivity was present.

34. Kashiwazaki H. Inaoka T. Suzuki T & Kondo Y (1986): Correlations of pedometer readings with energy expenditure in workers during free-living activities. Eur.J.Appl.Physiol 54, 585-590.

In a total of 23 subjects consisting of 10 clerical and 13 assembly workers in a factory, the pedometer readings during a day of free-living activity were analyzed for the relation with energy expenditure as determined by the simultaneously recorded 24-hour heart rate. The 24 hour energy expenditures in the clerical and assembly workers were 9515 kJ (2274 kcal) and 9698 kJ (2318 kcal) respectively. The whole day readings of the pedometer for all the subjects moderately correlated (r=0.438, p<0.05) with the net energy cost (NEC) as determined by subtracting the sleeping metabolic cost from the energy expenditure (clerical workers: r=0.781, p<0.01; assembly workers: r=0.1,38, p>0.05). The correlation analysis of the pedometer readings with the NEC in three activity phases in a day (work, commuting and staying at home) showed that the extent of the relationship differed by job types and activity phases. The best correlation was obtained during commuting in both of the job types (clerical workers: r=0.843. p<0.01; assembly workers: r=0.743, p<0.01). During work, a quite strong correlation (r=0.889, p<0.01) was obtained with the clerical workers but not with the assembly workers. No significant correlations were found in the data while the subjects were at home. The capacity of the pedometer to detect the impacts of body movements and the characteristics of activity is responsible for the differences in correlation. The limitations of the pedometer suggested in the present study must be taken into account if the device is to be used for measuring physical activity. A particular advantage of the device appears to be in its use for a sedentary population without regular strenuous exercise of static contractions.

35. Kaufman WC, Callin GD & Harris CE (1970): Energy expenditure of pilots flying cargo aircraft. Aerosp.Med. 41, 591-596.

Energy expenditure was determined by analysis of expired air collected from 21 engineering test pilots on 18 flights in three types of cargo aircraft, one jet-powered, and a helicopter. Samples were taken in the aircraft while preparing for flight, during routine flight, and during simulated emergency flight. Mean value for energy expended in routine flight was 49.3 kcal/m²hr, not significantly different from the 47.7 kcal/m²hr expended during preparation for flight. During emergency procedures energy expenditure rose to 70.2 kcal/m²hr. These values are not markedly different from values estimated for World War II aircraft. There was no significant difference in energy expended by pilots with extensive experience in the aircraft compared to pilots with little experience in the aircraft. Neither was there strong evidence of hyperventilation under any flight condition. These data suggest that less energy is expended in preparation for flight and routine flights, but more energy is expended during emergencies in the jet than in the helicopter or propeller aircraft.

36. Kemper HCG, van Aalst R. Leegwater A, Maas S & Knibbe JJ (1990): The physical and physiological workload of refuse collectors. Ergonomics, 33, 1471-1486.

Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands. In order to secure a safer and healthy work situation, the heavy physical loads imposed on 23 refuse collectors (aged 26-54) working in the city of Haarlem, in The Netherlands, were studied in a series of three experiments between 1984 and 1987. The aims were respectively (1) to study the load for workers collecting dustbins or polythene bags; (2) to introduce changes to reduce the load to avoid exceeding the overload criteria by individual refuse collectors; and (:3) to investigate the effects of interventions to improve the efficiency of refuse collecting. The maximal isometric lifting force (Fmax) and the maximal aerobic power (VO2max) of 23 refuse collectors were measured in the laboratory. Fmax was measured with an isometric dynamometer pulling with one arm from the floor; the mean value was 912 (+/-127)N. VO2max was measured running on a treadmill; the mean value was 43.3 (+/- 0.8)ml 02 per kg body mass per min. The physical load on the oxygen transport system was measured through work analysis and by a continuous registration of the heart rate over three working days. Criteria for overload were set at a mean external load of 20% Fmax and a mean energy expenditure of 30% VO2max and an energy expenditure of 50% VO2max or more for a maximum of 60 min per day. Replacement of dustbins by polythene bags resulted in a 70% increase in the total amount of refuse collected, an increase in throwing frequency, but a lower mean load per throw, and no significant differences in the mean heart rate over the working day. When polythene bags were used the mean values did not exceed the overload criteria, but 39% of the individual collectors did have a workload that was too high with respect to one of the criteria. In the last experiment the collectors were advised to reduce their work load by (a) lifting no more than two bags at a time; (b) reducing their walking pace; and (c) taking more breaks. Although compliance with the recommendations was good, and the weight lifted and the walking speed decreased, the physiological load remained the same. This may have been caused by a 15% increase in the total amount of refuse that had to be collected at that time.

37. Lambert Ml, Cheevers EJ & Coopoo Y (1994): Relationship between energy expenditure and productivity of sugar cane cutters and stackers. Occup.Med. 44,190-194.

MRC/UCT Bioenergetics of Exercise Research Unit, University of Cape Town Medical School, Observatory, South Africa. The main aim of this study was to measure the energy expenditure of sugar cane cutters and stackers during a normal working day and to relate this to their productivity (tonnes of cane cut or stacked per day). A secondary aim of the study was to relate the food and fluid ingestion of the workers during the day to energy expenditure, productivity and changes in body mass. Cutters (n = 12) and stackers (n = 12), who were randomly selected from all the workers (n = 50) on a Natal sugar estate in South Africa, wore heart rate monitors for the entire working day (7 h +/- 30 min). On a separate occasion, all subjects underwent treadmill exercise tests in which oxygen consumption VO2 and heart rate (HR) were measured simultaneously. A VO2-HR regression equation was calculated for each subject. Based on this regression equation, energy expenditure (kJ) for the working day was calculated for each subject. There was no difference in the mean productivity of the cutters (9.0 +/- 0.7 tonnes) compared to the stackers (9.0 +/- 0.5 tonnes). Both groups expended a large and similar amount of energy during the working day (cutters = 11,695 +/- 1288 kJ; stackers 14,127 +/- 1710 kJ). They ingested similar amounts of energy while working (cutters = 5179 +/- 161 kJ; stackers = 5281 +/- 324 kJ). The best predictor of productivity was the length of the working day (r = 0.63), followed by the energy expended (r = 0.60). Despite the large amount of fluid ingested (up to 6.0 litres/day), some workers lost more than 3% of their body weight. It can be concluded that the recommended amount of fluid ingested during the day needs to be individualized for each worker. This can be determined by monitoring their change in daily weight.

38. Lemon PWR & Hermiston RT (1977): The human energy cost of fire fighting. J.Occup.Med. 19, 558-562.

This study assesses the energy costs of four selected isolated fire fighting tasks. The four most strenuous fire fighting tasks as judged by the men and their administrators were selected for the study. Twenty male professional fire fighters, aged 23 to 43 years, served as subjects. After the men participated in a series of laboratory evaluation for % body fat, muscular strength and functional capacity (aerobic and anaerobic capacities), they participated in the four specified work tasks (aerial ladder climb, rescue of a "victim", hose drag and ladder raise). All tasks were performed at constant predetermined work rates. The results indicate that fire fighting consists of heavy physical work (~ 60-80% MVO2) even when the obvious external stresses present at an actual fire are eliminated (i.e., heat, humidity, decreased 02, increased CO2, as well as emotional stress). With the possible exception of MVO2, there appears to be little or no relationship between a number of the physical activities of the fire fighters and the individual physiological adaptations employed to meet the energy requirements of the task. Although MVO2 values were not significant (P<0.10>0.05), there was an indication that those fire fighters with MVO2's > 40 ml.kg^-1.min^-1 might be able to supply a greater percentage of the total 02 cost aerobically when compared to those men with MVO2's < 40 ml.kg^-1.min^-1. It was concluded that the level of physiologic work alone is not of sufficient stress to contribute significantly to the development of ischemic heart disease in fire fighters.

39. Littell DE & Joy RJT (1969): Energy cost of piloting fixed- and rotary-wing aircraft. .J.Appl.Physiol 26, 282-285.

The energy cost of piloting three US Army helicopters (light, utility, and medium) and one utility fixed wing aircraft was investigated. Energy expenditure was calculated from expired minute volume and expired air oxygen content measured during the basal state and in normal flight conditions. Data were collected on a total of 16 pilots, 5 of whom flew all three helicopters. All of the helicopter pilots were experienced test pilots. The data indicate that, for these pilots, and flying conditions studied (level flight in good weather) and aircraft, the energy cost must be classed as very light work, averaging 1.79 kcal/min. The energy cost of flying the fixed-wing aircraft by less experienced pilots was similar to previously reported energy expenditures for such aircraft. The data were segregated to separate measurements made at altitude from those made during flight in close proximity to the ground (take off, hover, etc.). In three of the four aircraft, the pilot's energy expenditure was greater when ground contact was possible.

40. Louhevaara V, Teraslinna P. Piirila P. Salmio S & Ilmarinen J (1988): Physiological responses during and after intermittent sorting of postal parcels. Ergonomics, 31, 1165-1175.

Physiological responses including ventilatory gas exchange, blood lactate (LA) and heart rate (HR) were studied during and after intermittent manual sorting of postal parcels in a simulated workplace constructed in the laboratory. Responses to parcel sorting were compared to those obtained during arm crank and cycle exercise. The subjects were 21 healthy male sorters. Their age was 33 +- 6 years and weight 78.3 +- 12.7 kg. The subjects maximal oxygen consumption VO2max was 2.52 +- 0.32 I/min^-1 for arm cranking and 3.24 +- 0.44 l.min^-1 for cycling. The subjects sorted parcels with a mean weight of 5.1 kg from a container onto two trollies for 3.5 min at each of the following work rates: slow (3+- 0 parcels.min^-1), habitual (8.6 +- 2.4 parcels.min^-1), accelerated (10.8 +- 3.1 parcels.min^-1 and maximal (16.9 +- 7.6 parcels.min^-1). The tasks were separated by rest periods of 30s for venous blood sampling, and the recovery was followed for 16 min. At the habitual work rate, VO2 was 1.36 +- 0.38 I.min^-1, LA 1.8 +- 0.9 mmol.l^-1, and HR 105 +- 22 beats.min^-1. The parcel sorting studied was predominantly aerobic (LA<4.0 mmol.l^-1) up to the work rate of about 20 parcels.min^-1. After the recovery period, breathing frequency and HR remained significantly higher than at rest. The physiological responses to parcel sorting substantially differed from those to arm cranking, whereas they were almost equal to cycling.

41. Malhotra MS, Chandra U. Rai RM, Venkataswamy Y & Sridharan K (1976): Food intake and energy expenditure of Indian troops in training. Br.J.Nutr. 35, 229-244.

1. Food intake and energy expenditure were determined on 500 soldiers drawn from infantry, artillery and engineer units of the Indian army, for 3 months during winter. 2. The units were located in two different regions of India at altitudes varying from sea level to 2300 m. 3. The energy requirements were assessed from the actual food intake as well as from energy expenditure and from the changes in body-weight and skinfold thickness. 4. The nutritional adequacy of the diet was assessed from clinical examination and changes in blood haemoglobin concentration. 5. The mean energy expenditure was found to be 15. 39 MJ (3679 kcal) and on this basis the energy requirements was 16.61 MJ (3970 kcal); energy intake was found to be 16.47 MJ (3936 kcal). 6. The energy contributed by protein, fat and carbohydrate was 0.115, 0.240 and 0.645 of the total intake respectively. 7. There was no significant change in bodyweight, blood haemoglobin level and skinfold thickness on this mean daily intake.

42. Malhotra MS, Chandra U & Sridharan K (1976): Dietary intake and energy requirement of Indian submariners in tropical waters. Ergonomics, 19, 141-148.

The energy expenditure of the Indian crew of a conventional submarine was assessed by the actual food intake and energy expenditure during exercise in tropical waters, for a period of 15 days in two phases. In phase 1, precooked, preserved and ready-to-eat rations were issued and in phase 11, rations served were cooked on board. The mean daily energy intakes during these two phases were 12.45 MJ and 11.80 MJ respectively. Kitchen and plate wastage was found to be 6%. Taking this wastage and 6%, extra loss during absorption into account, the dietary intake was found to balance the energy expenditure. The body weight and haemoglobin level was maintained during this period. It has been concluded that the daily energy requirement of an Indian submariner in tropical waters is about 12.54 MJ.

43. Morrison JF, Wyndham CH, Mienie B & Strydom NB (1968): Energy expenditure of mining tasks and the need for the selection of labourers. Journal of the South African Institute of Mining and Metallurgy, Nov. 185-191.

Despite technical advances, output in the gold mining industry of South Africa is to a large extent still dependent on the capacity of labourers to perform manual work. In some occupations the work is light, in others short spells of strenuous activity are followed by periods of inactivity or activitities of a relatively less strenuous nature. The main purpose of this investigation was to measure the energy expenditure, in terms of oxygen consumption in litres per minute, of men performing the most important tasks underground. Oxygen consumption measurements were made at three mins on men performing the following tasks: shovelling rock, tramming (pushing mine cars), transporting timber and building packs to support the hanging, barring loose rock from the face and hanging, operating rock drills, building stone walls, sweeping, attending to the filling of cars at the boxes situated at the bottom of the stoped, and operating winches. A Max Planck respirometer was used to collect samples of expired air while the men were carying out their tasks in the normal way. Oxygen consumption was determined by the procedures developed by Strydom et al (1965). The oxygen consumption of the different tasks showed considerable range and tasks were classified into light, moderate and heavy. It is suggested that labourers should be classified into categories on the basis of their maximum oxygen consumption and thus appropriateness for the different types of mining task.

44. Nag PK & Dutt P (1980): Circulo-respiratory efficiency in some agricultural work. Appl. Ergon. 11, 81 -84.

The cardio-respiratory performance of five subjects was studied in relation to two types of agricultural work, on germinating seedlings and threshing. Manual operations were compared with some simple implements. Transplanting of seedlings demanded 17.4 I/min (BTPS) pulmonary ventilation and 0.618 I/min (STPD) oxygen uptake. With the IRRI and the CRRI seeder, pulmonary ventilation and oxygen uptake were 41.9 and 39.6 I/min, and 1.910 and 1.638 I/min respectively. Pulse rates were 163 and 154 beats/min with the two seeders. The IRRI seeder required 4.1 man-hours per acre of land compared with 2.8 man-hours for the CRRI seeder. Manual threshing by beating demanded 28.1 I/min pulmonary ventilation and 0.920 I/min oxygen uptake and 135.8 pulse beats/min, the corresponding values in the case of pedal threshing were 41.2 and 1.310 I/min and 140.8 beats/min respectively. Pedal threshing is about 50% more efficient than manual threshing. However, static muscular activity is more reflected in pedal threshing than in threshing by beating.

45. Pal AK & Sinha DK (1994): The energy cost of metalliferous mining operations in relation to the aerobic capacity of Indian miners. Ergonomics, 37, 1047-1054.

Indian School of Mines, Dhanbad. Mining in India is still relatively unmechanized, and in the hot, humid, and noisy environment with uncomfortable postures, many work operations impose a considerable physiological strain. The physical characteristics, including aerobic capacities, of 54 workers in an Indian metalliferous mine have been studied, and their energy expenditures measured during long periods of work in different tasks. The mean VO2max was 2.32 +/- 0.6 I/min and the mean body mass was 60 +/- 4 kg. Averaged energy expenditures for different tasks ranged between 9.4 and 22.8 kJ/min and were usually more than 33% of the workers' maximal work capacity. Recommendations about reducing the stress of mining work are made.

46. Palka M (1975): An evaluation of work load in paving plate production. Ergonomics, 18, 271278.

During examination of work-load in the building construction industry, telemetric heart-rate and gasometric measurements were compared with results according to the Lehman, Spitzer and Hettinger's tables. The tabular methods showed a tendency to higher values of energy expenditure. Both experimental methods, heart-rate and gasometric, have almost identical values. In conclusion the author stresses that simplification of the evaluation of energy expenditure in the fields should proceed in the direction of simplifying the experimental methods and not in the direction of implementing the tabular method.

47. Ramana Murthy PSV & Belavady B (1966): Energy expenditure and requirements in agricultural labourers. Indian J.Med.Res. 54,977-979.

In India, 70% of the working force is employed in agriculture (Census, 1961). Energy expenditure in agricultural activities has been studied in some European and African countries (Passmore and Durnin, 1955). Similar studies on Indian agricultural labourers are scanty. A knowledge of the energy cost of the major agricultural activities would be useful in computing the daily energy requirements of labourers engaged in agriculture. The present report is the result of an investigation on energy expenditure carried out on agricultural labourers employed in the Agricultural College and the Agricultural Research Institute, Rajendranagar. Rajendranagar is a small village which is about 14 miles from Hyderabad. The agricultural practice at both the Institutes depended mainly on manual labour and was similar to conditions prevalent in rural areas.

48. Ramanathan NL & Datta SR (1968): Energy cost and mechanical efficiency of climbing stairs with loads. Current Science, 13, 366-367.

The energy cost of stair climbing was measured in seven healthy Indian volunteers by using the Douglas bag technique. The subjects climbed 96 steps (18,54 meters height, in 145 _ 3 sec (mean ± sd). Measurements were made in three different conditions: (1) climbing without load; (2) carrying 15 kg; (3) carrying 30 kg. The loads were carried on the head. The resulting energy expenditure for these tasks are (1) 3.91 kcal/min (2) 5.22 kcal/min (3) 6.13 kcal/min respectively. [not original abstract].

49. Ramanathan NL & Datta SR (1971): Ergonomical studies on load carrying up staircases. Part IV. Effect of load, rate of ascent and mode. Indian J.Med.Res. 59, 145-156.

A statistically designed experiment on ascending and descending stairs with load, speed and mode at two levels using eight subjects is reported. In all 128 experiments were required to cover all the permutations of load, speed and mode in this 2³ factorial design. The results established the statistical significance of the separate effect of load, speed and mode on the physiological responses of the subjects and the non-significance of any combined effect due to load, speed and mode during both ascending and descending stairs. Load, speed and mode, in this order, influence the energy cost and heart rate of individuals significantly to the 1% level. The findings of these experiments on load carrying on staircases are discussed, the practical aspects of the work are indicated and some guidelines for safe and efficient performance of this type of job recommended.

50. Ramanathan NL, Datta SR & Gupta MN (1972): Biomechanics of various modes of load transport on level ground. Indian J.Med.Res. 60, 1702-1710.

Seven modes of carrying a load of 30 kg on level ground by seven subjects have been compared in respect of physiological economy and biomechanical stress. The volunteers marched at the rate of 5 km/in carrying the load on the head, by hands, in packs and a yoke. The minute ventilation, oxygen consumption and pulse rate during work and recovery were determined. The double pack mode was the most advantageous ergonomically, while carrying by hands was the least desirable. The other modes lie between these extremes. Statistical significances of the differences have been presented. Carrying on the head approximated the double pack mode in advantage, probably because this happened to be the most familiar method to the volunteers. The biomechanical aspects of carrying loads in these modes are also discussed.

51. Ramaswamy SS, Dua GL, Raizada VK, Dimri GP, Viswanathan KR, Madhaviah J & Srivastava TN (1966): Effect of looseness of snow on energy expenditure in marching on snow-covered ground. J.Appl.Physiol 21,1747-1749.

The caloric requirements of walking on loose deep snow were determined in 12 young soldiers at an altitude of 2,270 m in North India. Oxygen requirements increased linearly with the depth of the snow until the imprints of the feet reached a depth of 37 cm. The oxygen requirements (in liters) for a 60-kg man covering the distance of 1 km was found to be expressed by the equation: Y=0.0 + 1.27 x X¹⁰³⁸, where X stands for the depth (in cm) of the foot impression. When the latter exceeded 37 cm, the oxygen requirements seemed to rise asymptotically in spite of the fact that the walking speed was slowed up by the increasing depth of the snow. This was explained as a consequence of the enormous increase in the swinging movements of the body. The respiratory stress during walking on loose snow was comparable to that experienced when running on snow-free ground at 8 km/hr or marching with a 70-lb load at 6 km/hr.

52. Raven PB, Colwell MO, Drinkwater BL & Horvath SM (1973): Indirect calorimetric estimation of specific tasks of aluminum smelter workers. J.Occup.Med. 15, 894-898.

Eleven male workers in a smelting department performed a bicycle ergometer test to assess VO2max In addition in eight males spot samples of expired gases were obtained with a lightweight gas collection system to measure the energy costs of a range of different activities. VO2 and % VO2max are presented for the 28 different activities that were studied. [not original abstract].

53. Rodahl K, Vokac Z. Fugelli P. Vaage O & Maehlum S (1974): Circulatory strain, estimated energy output and catecholamine excretion in Norwegian coastal fishermen. Ergonomics, 17, 585-602.

Circulatory strain and energy output were determined in 24 Norwegian coastal fishermen during a total of 35 work-days by indirect assessment based on computerized analysis of the continuously recorded heart rate by portable tape recorders. Urinary excretion of catecholamines was assayed as an index of stress response. The average, estimated energy expenditure of all activities on board during the whole day amounted to the equivalent of 0.9-1.1 I/min oxygen uptake and corresponded to 34-39% of the fishermen's maximal aerobic power with occasional peaks up to 80%. The heart rate exceeded 50% of the fishermen's heart rate reserve for 9-23% of the observation periods. The most strenuous activities were pulling in the seine with a power block (oxygen uptake up to 2.7 I/min) and unloading the catch, taxing the subjects by more than 50% of their maximal aerobic power for two-thirds of the duration of these activities. Continuous monitoring of the heart rate revealed the intermittent character of practically all activities on board. In a parallel study the circulatory strain, energy output and catecholamine excretion were investigated in eight catch handlers on land during a total of 12 work-days. Handling the catch entailed a mean oxygen uptake of 0.9 I/min, corresponding to about 34% of the maximal aerobic power of the workers, with peak values considerably lower and shorter duration than in the fishermen. The average (median) urinary excretion of norepinephrine (NE) and epinephrine (E) during the work-day was high in both investigated groups, 72 ng/min NE and 24 ng/min E in the fishermen, and 59 ng/min NE and 15 ng/min E in the catch handlers. The epinephrine excretion in the fishermen was significantly higher (p<0.01) than in the catch handlers.

54. Samanta A & Chatterjee BB (1981): Energy expenditure in manual load carriage. Ind.Health, 19, 145-154.

From observations on load carriage on subjects engaged solely for the manual carriage of compact loads of a given range of weights, over a range of self selected speeds, Gross Load (Body weight plus weight of external load) and the speed of carriage were found to be the principle influences in determining the energy expenditures of the tasks and the cardiorespiratory changes during their performance. Based on the data collected a chart has been developed which allows the strenuousness of load carriage tasks to be suitably altered by adjustments of Gross Loads and speeds of carriage so that they may not become unduly fatiguing for those employed in them.

55. Samanta A & Chatterjee BB (1981): A physiological study of manual lifting of loads in Indians. Ergonomics, 24, 557-564.

The employment of workers solely for lifting of loads is common in the developing countries. This task can be described in terms of its three principle variables, viz. the weight of the load, the height of the lift and the rate of lifting, but few attempts to quantitate the contributions of these variables in determining its strenuousness have been made. Based on the observed range of variation in an industrial lifting operation, a total of 525 lifting experiment, comprising of three different weights of compact loads, lifts to three separate heights from the ground level and three different rates of lifting were carried out on 21 subjects selected from amongst the load lifters. Comparison of the observed energy expenditure of these tasks with maximum working capacities of the subjects showed that many of the tasks were unduly heavy. Regression equations depicting the relation between the energy expenditure of lifts of different heights with the other two variables are given. A chart linking these variables has also been prepared; this may be helpful in adjusting those lifting tasks which are continued for prolonged periods so that they are of 'acceptable' heaviness.

56. Samanta A, Datta SR, Roy EN, Chatterjee A & Mukherjee PK (1987): Estimation of maximum permissible loads to be carried by Indians of different ages. Ergonomics, 30, 825-831. Porters in different age groups, 20-29 yr, 30-39 yr, 40-49 yr, and 50 yr and above, carried loads of 0, 20, 30, 40, 50, and 60 kg, within the range carried by them in their daily work, at a fixed speed of 5 km.h^-1, the average normal speed of walking with loads. The range of oxygen consumption relative to measured maximum oxygen uptake (VO2max) suggests that the maximum permissable loads to be carried at 5 km.h^-1 by subjects in these age groups are 41, 23, 21 and 11 kg respectively.

57. Sen RN & Nag PK (1975): Work organization of heavy load handling in India. J.Hum.Ergol. 4, 103-113.

The physical work rate, the energy and the cardiac costs of 27 young male workers from the eastern part of India in five groups handling loads of about 30, 60, 75, 90, and 125 kg, respectively, were ascertained with the objective to rationalize the rate of work based on the physiological responses of the workers. The mean rate of usual work of the groups (I to V) was 4, 715, 8,020, 7,350, 6,100, and 7,600 kg-m/min, respectively, which was considered to be extremely heavy. From the mean values of all the groups for the average work pulse rate of 143.1 beats/min, the recovery-pulse-sum of 119 beats for the first five minutes of recovery, the first and third minute recovery pulses of 127 and 114, respectively, the oxygen-pulse of 0.25 ml/pulse/kg, and the energy cost of 9.1 kcal/min, it was suggested that excepting the first group, the workers were working at a level much higher than the 50% level of their maximal working capacity. The simple and multiple linear correlation coefficients between the rate of work and the various physiological parameters were significant and different linear regression equations were suggested. In conclusion, for extremely heavy types of work in India, 1,200 kcal as the net optimal energy output in an 8-fur working day is suggested.

58. Shiraki K, Sagawa S. Konda N. Park YS, Komatsu T & Hong SK (1986): Energetics of wet-suit diving in Japanese male breath-hold divers. .J.Appl.Physiol 61, 1475-1480.

The present study was undertaken to investigate energy balance in professional male breath-hold divers in Tsushima Island, Japan. In 4 divers, rectal (Tre) and mean skin (Tsk) temperatures and rate of 02 consumption (VO2) were measured during diving work in summer (27 °C water) and winter (14 °C water). Thermal insulation and energy costs of diving work were estimated. In summer, comparisons were made of subjects clad either in wet suits (protected) or in swimming trunks (unprotected), and in winter, they wore wet suits. The average Tre in unprotected divers decreased to 36.4 +/- 0.2 °C at the end of 1-h diving work, but in protected divers it decreased to 37.2 +/- 0.3 °C in 2 h in summer and to 36.9 +/- 0.1 °C in 1.5 h in winter. The average Tsk of unprotected divers decreased to 28.0 +/- 0.6 °C in summer and that of protected divers decreased to 32.9 +/- 0.5 °C in summer and 28.0 +/- 0.3 °C in winter. Average VO2 increased 190% (from 370 ml/min before diving to 1,070 ml/min) in unprotected divers in summer, but in protected divers it rose 120% (from 360 to 780 ml/min) in summer and 110% (from 330 to 690 ml/min) in winter. Overall thermal insulation (tissue and wet suit) calculated for protected divers was 0.065 +/- 0.006 °C.kcal-1.m-2.h-1 in summer and 0.135 +/- 0.019 °C.kcal-1.m-1.h-1 in winter. Total daily thermal cost of diving work was estimated to be 425 kcal/m2 in summer (276 min work) and 482 kcal/m2 in winter (240 min work).

59. Shoenfeld Y. Udassin R. Shapiro Y. Birenfeld C, Magazanik A & Sohar E (1978): Optimal back-pack load for short distance hiking. Arch.Phys.Med.Rehabil. 59, 281-284.

Twenty young men marched 6 and 12 km with a well-fitted back-pack load of 30 or 35 kg. Each subject served as his own control. No significant increase in mean heart rate, rectal temperature, or decrease in mean VO2 max and serum levels of glucose and muscle enzymes were recorded in the groups marching 6 km with 30 and 35 kg. Significant differences in the increases in mean heart rate, the decreases in VO2 max and the changes in blood glucose were noted between the two groups carrying 30 and 35 kg for 12 km. These significant differences were also supported by the subjective feelings of the volunteers. The present study shows the optimal back-pack load for healthy young men, marching at 6 km/hr on a paved level road, to be 30 kg for 12 km and 35 kg for 6 km without considering the task too difficult and with no significant decrease in VO2 max. The results are relevant to hiking, rescue assignments, and military missions.

60. Spurr GB, Barac-Nieto M & Maksud MG (1975): Energy expenditure cutting supercane. .J.Appl.Physiol 39, 990-996.

VO2 VE, and heart rates (fH) were measured in 61 Colombian sugarcane cutters while harvesting cane in the am and pm and in the laboratory during a VO2max test. Productivity and sweat rates were also measured in the field. The subjects had an estimated dietary intake of 2,970 kcal/day, which was lower than calculated daily energy expenditure. During the work measurements the VO2 was 1.5 1/min, VE 48 1/min, and fH 135 beats/mini there were no differences between am and pm values. The subjects sustained about 35% of VO2max during the 8 h workday, but worked at 57% of VO2max during the tests. Measured energy cost was 7.4 +/1.5 kcal/min during the workday. Sweat rates were higher pm than am (5 kg/8 h day). Grouping of the men according to productivity demonstrated that taller, heavier men were better producers and had lower calculated heart rates at VO2 1.51/min. Efficiency of cane cutting was higher (9%) pm.

61. Spurr GB, Barac-Nieto M & Maksud MG (1977): Efficiency and daily work effort in sugar cane cutters. Br.J.lnd.Med. 34, 137-141.

Productivity (metric tons (tonnes)/day), efficiency (kg cane cut/litre Vo2), and effort (percent Vo2 max sustained during an 8-hour workday) have been measured in 54 Colombian sugar cane cutters. In workers who sustained less than 40% Vo2 max during the workday, the effort expended was related to productivity (r = 0.71) but efficiency and productivity were not significantly correlated. In 16 workers sustaining a greater than 40% Vo2 max during the workday, productivity and effort were not related and efficiency was significantly reduced. Subjects using less than 40% Vo2 max were divided into good, average and poor producers and compared with the men with low efficiencies. In general, these inefficient men had the anthropometric and physical fitness characteristics of low productivity workers (smaller stature, weight and Vo2 max). However, the frequency of good, average, and poor cutters in the inefficient group did not differ from that of the men expending less than 40% of their maximum effort nor was their average productivity different. No obvious reasons for the differences in efficiency and effort of these men were found.

62. Spurr GB, Maksud MG & Barac-Nieto M (1977): Energy expenditure, productivity, and physical work capacity of sugarcane loaders. Am.J.Clin.Nutr. 30, 1740-1746.

VO2, E and heart rates (fH) were measured in 28 Colombian sugarcane loaders while loading cane and in the laboratory during a VO2max test. Productivity (metric tons.day-1) of the workers was also obtained. During work, VO2 was 1.25 I.min-1, VE 38.8 I.min-1, and fH 120 beats.min1. The subjects worked at 42% of VO2max (6.3 +/- 1.0 kcal.min-1) during the field measurement periods. Energy expenditure was estimated to average 3,281 kcal.24 hr-1. Productivity was higher in men with lower fat content, resting fH and fH at VO2 = 1.25 I.min-1, indicating a positive relationship between productivity and physical fitness. Productivity was not related to age but, since VO2max decreased with age, the relative effort required to maintain productivity increased in the older workers. Efficiency (kg cane loaded.I VO2-1) and estimated sustained effort (percent VO2max were not significantly correlated with productivity in this type of discontinuous, moderate work.

63. Thornton R. Brown GA & Higenbottam C (1984): The energy expenditure of helicopter pilots. Aviat. Space Environ. Med. 55, 746-750.

The energy expenditure of Army Air Corps and Royal Air Force pilots has been measured during flight in Gazelle and Puma helicopters respectively. Heart rates were also recorded. The results were compared with resting values obtained in the crewroom before flight, and confirmed the findings of other authors that the energy cost of flying helicopters in level flight is about 50% higher than that of sitting at rest.

64. Tin-May-Than & Ba-Aye (1985): Energy intake and energy output of Burmese farmers at different seasons. Hum.Nutr.Clin.Nutr. 39C,7-15.

The food intake and energy expenditure of ten farmers aged 18-60 years were studied for 3 d in the monsoon season, and for 6 d in harvest and in summer. The mean daily energy intakes +/s.e. in the three seasons were 39!;0 +/- 180 kcal (16.8 +/- 0.8 MJ), 3690 +/- 280 kcal (15.4 +/1.15 MJ), and 2900 +/- 180 kcal (12.5 +/-0.8 MJ), respectively. Energy outputs were 3840 +/130 kcal (16.05 +/- 0.5 MJ) in the monsoon, and 2940 +/- 130 kcal (12.3 +/-0.5 MJ) in harvest and 2230 +/- 80 kcal (9.3 +/- 0.35 MJ) in summer. According to the classification given by FAD/WHO (1973) our Burmese farmers expended energy corresponding to exceptionally active work during the monsoon and harvest, and to light activity during the summer. Nevertheless, their daily intakes at all seasons fulfilled the requirement for very active and exceptionally active work set by FAD/WHO (1973) and also covered their energy expenditure. In contrast to the published values for food consumption of farmers in developing countries, our study shows adequate energy and protein intakes. The study indicates that food intake is not the limiting factor in energy expenditure in this farming community.

65. Torner M, Blide G. Eriksson H. Kadefors R. Karlsson R & Petersen I (1988): Workload and Ergonomics measures in Swedish professional fishing. Appl.Ergon. 19, 202-212.

The major types of professional coastal fishery in Sweden were studied. A questionnaire indicated that symptoms from the musculo-skeletal system were common and that certain symptoms related to certain types of fishing. Working tasks inducing severe workload were identified. They concerned handling the fishing gear as well as handling the catch. Ergonomics measures to decrease the workload were suggested and evaluated through Ergonomics assessment, measurements of oxygen uptake and working posture analyses. It was found that Ergonomics measures can be taken which are efficient in reducing the load on the musculo-skeletal system of the fishermen.

66. Viteri FE, Torun B. Galicia JC & Herrera E (1971): Determining energy costs of agricultural activities by respirometer and energy balance techniques. Am.J.Clin.Nutr. 24, 1418-1430.

Eighteen Guatemalan agricultural workers who had received an excellent diet for 3 years prior to the study were investigated in regard to body composition, energy cost of work of 37 agricultural activities, dietary intake, time-motion studies, and energy balance. A detailed description of the methodology used and of the results obtained is presented. The subjects' body composition was normal, except for only two relatively obese individuals. However, muscle mass was smaller than that determined in a group of normal military academy students. The energy cost of work of the various activities measured agreed with published values from both developed and developing countries, except for the results published from India, which were lower. Caloric balance was, on the average, -138 kcal/day, and mean weight loss, -299 in 3 days. In 14 of the 18 subjects, there was a high correlation between pulse taken for 15 sec after the end of each activity and oxygen consumption. In general, respiratory minute volume agreed better with VO2 than pulse, following an essential linear regression, except in severe exercise situations.

67. Wyndham CH & Heyns A (1967): Energy expenditure and mechanical efficiencies in pushing a mine-car at various speeds and loads. Int.Z.angew.Physiol.einschl.Arbeitsphysiol. 24, 291 314.

Despite the mechanisation of most industrial processes which reduces the physical effort required of the labour force, there are many mining operations which it is not economical to mechanise. Pushing mine cars is one these and few studies have examined the energy cost of this activity. The purpose of this study was to investigate this and also the effects of different loads and speed of pushing on rates of energy expenditure. Five Bantu mine workers were selected randomly and after training carried out 25 different combinations of speed and load. Each combination was tested three! times. Analysis of oxygen consumption versus the task load at different speeds showed that maximum efficiency occurred as the load increased, but at low speeds. A diagram is presented which shows different combinations of speed and load at which mine labourers can work with optimum efficiency without undue physiological strain. [not original abstract]

Foreign language references

1. Bondarev Gl, Demina DM, Dupik VS & Ratner EM (1978): [Energy metabolism and the requirement for food and energy in Baikal-Amur mainline workers engaged in clearing strips through the forest]. Vopr.Pitan. 60-63.

Indirect calorimetry and time studies showed the diurnal energy expenditure in wood fellers to be 5186.2, in their helpers 4476.9 and in branch choppers 5246.9 kcalories. In accordance with these energy expenditures requirements of the mentioned category of workers in energy, nutrients and other essential nutritional factors have been elaborated. Recommendations for organization of nutrition in the field are given.

2. Demina DM, Ratner EM & Bondarev Gl (1981): [Energy expenditure of operators of mechanized columns in the construction of the Baikal-Amur mainline]. Vopr.Pitan. 35-37.

Basing on the study of the daily time and energy metabolism budgets in various types of production and non-production activities, it has been established that in summer the daily energy consumption in the drivers of mechanized columns amounts to not more than 3200 kcal, being equal to 3500 kcal in winter. These data form the basis of the determination of energy and food requirements of the group of workers under consideration.

3. Frauendorf H. Kobryn U. Kohn Seyer G & Nehring P (1980): [Biological effort of male workers involved as manual laborers in drain pipe production]. Z.Gesamte.Hyg. 26, 777-780.

Physiological tests (measurements of heart rate and energy turnover) were performed on setters and transfer men during the production of drain pipes. Based on a time and motion study and taking into account breaks, the mean heart rate was calculated to 121 beats/min and the total energy metabolism 2,400 kcal (= 10 MJ) or a working energy metabolism of 1,824 kcaal (= 7,635 kJ) at mid shift. Transfer men doing the same work were found to have a heart rate of 128 beats/min and a total energy metabolism of 2,100 kcal (= 8,790 kJ). Their working energy metabolism was 1,524 kcal (= 6,380 kJ).

4. Frauendorf H. Kohn Seyer G & Gelbrich W (1981): [Heart rate and energy expenditure in selected physical tasks in steel foundries]. Z.Gesamte.Hyg. 27, 30-34.

Industrial physiological examinations of the jobs of machine moulders, hand moulders, cleaners, grinders and shakers-out were carried out in two steel foundries having different levels of mechanization. Based on heart rates and energy expenditure measured during random tests and on data obtained from work routine studies, the effort for each activity was determined. The results obtained for the two steel foundries were compared and discussed.

5. Frauendorf H. Kohn Seyer G & Hoffmann B (1978): [The biological effort put up by male workers in the unloading of sawn wood using different technologies]. Z.Gesamte.Hyg. 24, 168-172.

Occupational hygiene tests were carried out on male workers unloading sawn wood by hand and mechanically. The biological effort involved in unloading work was determined on the basis of the heart rate and energy metabolism values obtained during the tests. In the case of manual unloading, the working heart rate values were in the region of 61 +/- 11 beats/min (heart rate 142 +/- 16 beats/min), the working energy metabolism values were 6.5 +/- 1.3 Akcal/min (= 27.2 +/5.4 AkJ/min). The corresponding values recorded when unloading with the aid of machines (forklift trucks, slewing cranes) were 30 +/- 8.3 beats/min (heart rate 119 +/- 27 beats/min abd 3.9 +/- 1.1 Akcal/min (= 16.3 +/- 4.6 AkJ/min) for the working energy metabolism. The results show that the amount of biological effort involved is lower when using mechanical equipment.

6. Gritsevskii MA, Bashkirova LS & Zaitseva Zhl (1994): [Work capacity of the operators of chemical industry and its effect on motor activity]. Med.Tr.Prom.Ekol. 24-26.

Motor activity, energy metabolism, work productivity, functioning and regulation of cardiovascular system were examined in machine operators working at 2 chemical enterprises. The energy loss within the shift appeared to vary from 800 to 1200 kcal, that within the day from 2,500 to 2,900 kcal. The examinees demonstrate lack of physical training that affects the functioning of cardiovascular system. However, the study found no correlation between the Physical State Index and the work productivity. The elderly operators show higher work productivity associated with more noticeable lack of physical training. The authors conclude also that daily amount of physical load should be considered in evaluation of low physical training impact.

7. Istomin AV & Chizhov SS (1995): [Factual nutritional status in workers of a machine-building factory]. Gig.Sanit. 17-19.

Physical development, energy expenditures, morbidity, and supply with the main food-stuffs were studied in machine-building workers. Peculiarities of alimentary status of workers were basis for development of hygienic recommendations on rationalization of their nutrition.

8. Martin G. Frauendorf H. Erdmann E & Kohn-Seyer G (1979): [Work-physiology studies on the transportation of large waste-disposal containers used in municipal waste-disposal service]. Z.Gesamte Hyg. 25, 283-287.

Industrial hygiene examinations were carried out on a crew of dustmen of a minicipal waste disposal vehicle using large waste disposal containers (with capacities of 1.1 m³ and 0.55 m³). The physical strain involved was assessed on the basis of energy exchange and heart rates. The values measured in relation to active phases in two catchment areas were 4.8 Akcal = 20.1 AkJ/min at 45 working heart beats per minute and 3.4 Akcal/min = 14.3 AkJ/min at 32 working heartbeats. By extrapolating the energy exchange for the whole shift, the authors obtained a value of 3872 AkJ = 924 Akcal. The breaks that occur in the normal working cycle are seen as sufficient for recovery.

9. Martin G. Frauendorf H. Erdmann U. Kohn Seyer G & Vildosola Jl (1980): [Industrial physiological studies on trashmen during domestic refuse removal using 110-liter trash barrels and large trash receptacles]. Z.Gesamte.Hyg. 26, 579-582.

The energy exchange and pulse rates of dust men were measured while they were handling 110 litre waste bins and large waste! containers (with capacities of 0.55 m³ and 1.1 m³) in order to determine the physical strain involved in domestic waste disposal work. When handling waste bins, the dustmen were found to have an energy exchange rate of 24.2 AkJ/min (5.8 Akcal/min) and a pulse rate of 52/mint The extrapolation of the energy exchange ratio for the whole shift yields 7,027 AkJ (1,677 Akcal). The mean energy exchange calculated during the handling of large waste containers was 18 AkJ/min (4.3 Akcal/min) and the mean heart rate 40 beats/mint The energy exchange value obtained by extrapolating for the whole shift was 3,972 AkJ (924 Akcal). Based on these tests it can be concluded that the physical stress involved in handling large waste containers is less than that involved in handling conventional 110 litre waste bins, despite the fact that larger quantities of waste per unit time are handled with the larger waste containers.

10. Martinic I (1995): [Evaluation of physical exertion by statistical analysis of worker's heart rate at log skidding]. Arh.Hig.Rada.Toksikol. 46, 23-32.

Faculty of Forestry, University of Zagreb, Croatia. Results of investigation into the physical exertion of the log skidding workers: tractor driver, winch operator and choker are presented. The investigation consisted of laboratory and field measurements and included measurements of the heart rate and assessment of the work effect, the work time structure, and the worker's physical exertion and energy consumption. According to the average rate during daily work, the physical exertion of the tractor driver and winch operator was classified as low exertion (75-95 min-1), whereas that of the choker was established as medium exertion (96-115 min-1). Energy consumption was calculated for the daily working time of 262 minutes, according to field measurements and for normal eight-hour work. According to field measurement values the tractor driver's and winch operator's work was categorized as light work (1.23-2.51 MJ) and that of the choker as heavy work (2.52-6.30 MJ). According to the values for eight-hour work, the tractor driver's and the winch operator's jobs were classified as heavy work (2.52-6.30 MJ/8 h) and the choker's job as the heaviest (6.31-10.47 MJ/8 h).

11. Maver H. Kovacevic M & Grgic Z (1994): [Energy expenditure in workers who install plastic and metal pipes for water supplies and sewage]. Arh.Hig.Rada.Toksikol. 45, 367-372.

Hrvatsko antropolosko drustvo, Zagreb. The mounting of plastic and metallic water and sewage tubes is the type of work that requires a very high energy expenditure: 45 kJ/min, 9631 kJ for eight working hours and about 17,000 kJ for a working day. Working conditions involve a very demanding working posture, carrying of heavy loads and poor weather conditions. The work is considered to be very heavy physical work.

12. Peters H. Muller B & Hettinger T (1981): [Survey of work load and stress in heat-exposed work stations in the iron and steel industry]. Zentralb. Arbeitsmed. Arbeitsschutz. Prophyl. Ergonomie. 31, 356-367.

Strain in the workplace and resulting stress need to be measured and interpreted when assessing the workplace situation. The procedures described here for collecting and summarising data about activities characterised by physical work in conjunction with high climatic strain are being used in a research project currently being carried out in work areas of the iron and steel industry.

13. Peters H. Muller B & Hettinger T (1982): [Work related energy expenditure while working at a steel plant]. Zentralb.Arbeitsmed.Arbeitsschutz.Prophyl.Ergonomie. 32, 138-141.

Work strain caused by dynamic muscle work is described here in terms of work expenditure. This is determined by measuring the consumption of oxygen in individual experiments in the workplace using the integral or partial method. Evaluation by means of an easy to use estimate formula enables immediate verification of the results of the experiments. The results of work expenditure measurements in the smelting and casting workshops of various steel-making plants (basic oxygen steel-making plant, electric steel plant, Siemens-Martin steel plant, bottom casting, continuous casting) are described together with the activities carried out.

14. Peters H. Muller BH & Hettinger T (1983): [Work-energy expenditure of metallurgy occupations]. Zentralb.Arbeitsmed.Arbeitsschutz.Prophyl.Ergonomie. 34, 16-20.

Dynamic muscle work still represents today one of the most significant types of strain in the industrial workplace. The level of strain is described here in terms of work expenditure, which is determined in individual experiments in the workplace by measuring the amount of oxygen used. The results of analyses of work expenditure in the fields of coking plants, blast furnace works, flame chipping, casting, annealing plants and open hearths (Siemens-martin) steel plants are shown and the activities involved each time are described.

15. Weiler T. Jaercke-Hubschle F & Landau K (1990): [Determination of energy conversion during work with hand-guided motor mowers]. Zentralb.Arbeitsmed.Arbeitsschutz.Prophyl. Ergonomie. 40,12-16.

Hand-guided motor mowers are two-wheeled tractors, which working persons used mainly to cut grass under very difficult topographic conditions where higher mechanized work devices can no longer be used. Persons, who work with these mowers, are exposed to high energetic stress. Despite this, there is a big lack of knowledge concerning the quantity of energy conversion and possibly resulting restrictions of labour assignement. For a detailed analyses of stress the Ergonomic Job Analysis Procedure (Arbeitswissenschaftliches Erhebungsverfahren zur Tatigkeitsanalyse abbreviated in German AET) was used first. By the following determinations of energy conversion using a respirometer (Morgan Oxylog) an average value of energy conversion of 14 kJ/min was found. But it shouldn't be neglected that during the laboratory studies, the long-term performance limit of 17 kJ/min and 20 kJ/min, according to Lehmann and DIN 33 403 (June 1988), has been exceeded four times.

(introductory text...)

1. Astrand (1971): Estimating the energy expenditure of housekeeping activities. Am.J.Clin.Nutr. 24, 1471-1475.

The daily energy expenditure of 10 housewives was studied by heart-rate telemetry. The mean heart rate was related to oxygen consumption by individual heart rate-oxygen consumption regressions from work carried out on a bicycle ergometer. Comparisons were made of this technique against direct respired air collection in three subjects and the techniques varied 0.1 liter 02/mint The housewives worked at 40% of their maximum aerobic work power.

2. Banerjee B. Khew KS & Saha N (1971): A comparative study of energy expenditure in some common daily activities of non-pregnant and pregnant Chinese, Malay and Indian women. J.Obstet.Gynaecol.Br.Commonw. 78, 113-116.

Twenty-five pregnant Chinese women (11 during both second and third trimester and 14 in third trimester only) and 17 non-pregnant Chinese women, 14 third-trimester pregnant and 10 non-pregnant Malay women, and 14 third-trimester pregnant and 10 non-pregnant Indian women were tested for energy cost during rest and under various common daily activities. It was found that the third trimester pregnant women of all three races expended significantly more energy per minute than the respective control groups during rest and in the majority of common daily activities such as sitting and reading, sitting and writing, ironing and washing small clothes. But it was also observed that the percentage increase of expenditure over resting metabolism in every activity was more in non-pregnant controls than in pregnant women indicating that the pregnant women performed tasks in a more relaxed and economical way than the non-pregnant controls. Eleven pregnant Chinese women expended in varying degrees more energy per minute in the third trimester pregnancy than in the second. (The body weights of the present pregnant groups were lower than the European standard.).

3. Banerjee B & Saha N (1981): Energy balance study in pregnant Asian women. Trop.Geogr.Med. 33, 215-218.

Twenty-four pregnant Asian women resident in Singapore were tested for the determination of energy cost of rest and various common daily activities. The average daily energy expenditure was estimated from a diary of activities of seven days. The average daily energy intake was computed from Food Tables on the basis of consumption of measured dressed raw materials of food over seven days in the same period of measurement of energy expenditure. The average daily energy intake and expenditure in this group of pregnant women were found to be 2020 and 1810 kcal (8.5 and 7.6 MJ) giving a balance of +210 kcal (0.9 MJ) per day.

4. Bleiberg FM, Brun TA, Goihman S & Gouba E (1980): Duration of activities and energy expenditure of female farmers in dry and rainy seasons in Upper-Volta. Br.J.Nutr. 43, 71-82.

1. Fifteen female farmers (aged 18-47 years) from two villages of the Mossi Plateau in Upper-Volta participated in a survey in which their daily activity pattern and their energy expenditure were assessed. Eight of the subjects were investigated twice, in March (dry season) when there is no agricultural activity, and in July-August (rainy season) when heavy physical work is performed: mostly hoeing, weeding and replanting sorghum (Sorghum vulgare) and millet (Pennisetum typhoides). 2. The mean height was 1.57 m and the mean weight 50.6 kg. The average percentage of body fat, calculated from skinfold thickness, was comparable to that of European females but the triceps skinfold was more than 60% below the standard value (Jelliffe, 1969). The type of activities and the period of time spent on each activity changed significantly with the season. The mean energy output rose from 9.7 MJ (2320 kcal) in March to 12.1 MJ (2890 kcal) in July-August for a 55 kg standard weight. 3. In this paper, the extent of both the daily activity pattern of women living in a subsistence agriculture and their energy output is estimated. The results suggest that during the rainy season, the energy requirements of female farmers are much higher than usually estimated.

5. Brun T (1992): The assessment of total energy expenditure of female farmers under field conditions. J.Biosoc.Sci. 24, 325-333.

Institut Agronomique Mediterranéen de Montpellier, France. The paper reviews methods, and their difficulties, in the measurement of the daily energy expenditure of rural women under field conditions in developing countries. Since all methods need to be validated against a reference method which is usually based on indirect calorimetry, examples of the use of this technique are given. The energy costs of most agricultural and daily tasks of rural women in developing countries have been measured. Large intra- and inter-individual variations in the cost of a single activity occur, so repeated measurements are needed to obtain a valid mean energy cost for a specific activity for a homogeneous group of individuals. Much work remains to be done on the assessment of the duration and the intensity of the physical activity of the rural adolescent and adult female population. Studies indicate that the workload of most rural women in developing countries is excessive and frequently associated with acute poverty.

6. Devadas RP, Anuradha V & Rani AJ (1975): Energy intake and expenditure of selected manual labourers. Ind.J.Nutr.Diet. 12, 279-284.

The energy intake and expenditure of adolescent girls doing manual work in building construction was determined. Energy intake was calculated from a seven day food diary. The energy expenditure of different construction work activities was measured by indirect calorimetry using a Kofranyi-Michaelis respirometer. Energy costs per minute were calculated using the formula given by Bratton. The total energy expenditure of subjects was calculated by the factorial method using these values and additional values from published tables. Their food and energy intake were found to be below the allowance recommended by ICMR. Further research is needed on: 1) allowances for energy for adolescents performing heavy work in India; and 2) standard values of energy expenditure for non-occupational activities performed by Indians of different age and sex.

7. Dufour DL (1984): The time and energy expenditure of indigenous women horticulturalists in the northwest Amazon. Am.J.Phys.Anthropol. 65, 37-46.

The energy cost of subsistence activities and the daily time and energy budgets of Tatuyo women were assessed as part of a village energy flow study. The Tatuyo are swidden horticulturalists relying on bitter manioc (Manihot esculenta) as a staple crop. Except for the actual felling of new gardens, women are responsible for most of the horticultural work and food preparation. Time budgets were assessed using 24-hour activity diaries. Rates of energy expenditure in typical activities were measured by indirect calorimetry using a Max-Planck respirometer. Daily energy expenditure was calculated using these rates in conjunction with the activity diaries. Rates of energy expenditure in standard activities were moderate and broadly comparable to published values for other populations living in tropical environments. The mean daily energy expenditure was 2,133 kcal (8.9 MJ). This value is similar to that reported for other subsistence horticulturalists and close to the FAO recommendation for energy intake for moderately active individuals.

8. Geissler CA, Brun TA, Mirbagheri I, Soheli A, Naghibi A & Hedayat H (1981): The energy expenditure of female carpet weavers and rural women in Iran. Am.J.Clin.Nutr. 34, 2776-2783.

The energy cost of individual activities and the daily energy expenditure of female carpet weavers and villagers were measured in Iranian villages and in the town of Isfahan as part of a series of studies to assess the validity for the population of past and present FAO recommended energy allowances. The energy cost of typical activities was measured by indirect calorimetry using Max-Planck respirometers. Daily energy expenditure was assessed using these figures combined with a 24-hr activity diary. The results of standard activity values are compared with other published values for Europeans and populations of countries with hot climates. The mean daily energy expenditure for both groups was in the order of 2000 kcal/day, below but close to the FAO recommendations which appear valid for rural women in a large part of the country but are probably an underestimate for areas where the participation of women in agriculture is greater.

9. Htay H. Po L & Mya-Tu M (1978): Habitual physical activity of rural Burmese women. Ergonomics, 21, 239-252.

Habitual physical activity of 16 Burmese women aged 19-24 yrs residing in a rural Burmese village was assessed by the questionnaire method together with the diary method and heart rate measurements. The pattern of their habitual physical activity had a seasonal variation. Their heart rate during transplanting paddy, pounding glutinous paddy and carrying water ranged from 108132, 119-144 and 120-168 beats.min^-1 respectively. Their work intensity expressed as a percentage of their maximal aerobic power varied from 13.04 to 79.47. It was found that the habitual physical activity of these rural women could contribute a positive effect towards their physical performance capacity.

10. Kang DH, Park YS, Park YD, Lee IS, Yeon DS, Lee SH, Hong SY, Rennie DW & Hong SK (1983): Energetics of wet-suit diving in Korean women breath-hold divers. .J.Appl.Physiol 54, 1702-1707.

Contemporary Korean women divers wear wet suits during diving work to avoid the cold water stress. The present study was undertaken to evaluate the effect of wearing wet suits on the daily thermal balance of divers and on the duration of diving work. Rectal (TR) and skin temperatures and 02 consumption VO2 were measured in four divers before and during diving work in summer (22.5°C water) and winter (10°C water). Subjects wore either wet suits (protected) or cotton suits (unprotected) for comparison. TR decreased 0.4°C in summer and 0.6°C in winter after 2 h of diving work in protected divers, while it decreased to 35°C in 60 min in summer and in 30 min in winter in unprotected divers. Mean skin temperature of protected divers decreased to 31°C in summer and 28°C in winter, while that of unprotected divers decreased to 24°C in summer and 13°C in winter. VO2 toward the end of the diving work period increased by 80 (summer) and 140% (winter) in protected divers and by 160 (summer) and 250% (winter) in unprotected divers. From these values total thermal cost of diving work was estimated to be 260 and 370 kcal . day-1 in summer and winter, respectively.

11. Lawrence M, Singh J. Lawrence F & Whitehead RG (1985): The energy cost of common daily activities in African women: increased expenditure in pregnancy? Am.J.Clin.Nutr. 42, 753763.

A total of 1546 measurements of energy expenditure on 142 nonpregnant, pregnant, or lactating Gambian village women were performed by open-circuit indirect calorimetry. Of the 47 common daily activities measured, only 7 would be classified as moderate according to internationally accepted standards, the remainder being light (ie requiring less than 3.5 kcal/min). This was unexpected since many of the tasks, judged subjectively, appeared quite demanding. Furthermore there was no increase towards the end of pregnancy in the energy cost of a range of activities requiring 1-5 kcal/min and involving a variety of body movements, despite the substantial weight gains observed. Only for walking was there the expected increase in energy expenditure. Although in the past it has been assumed that the heavier pregnant women would require additional energy for activity, no special allowance for this is included in current dietary recommendations. The present results indicate that, for women from the developing world, no allowance is necessary. The finding that most activities were light is also of relevance to total energy requirements in this community.

12. Nag PK & Chatterjee SK (1981): Physiological reactions of female workers in Indian agricultural work. Hum.Factors, 23, 607-614.

The physiological reactions of eight female workers in agricultural tasks and in leisure time activities were determined with a view to standardizing occupational workload. Maximal oxygen uptake (V_O2max) was 1.892 L per minute. Their daily energy intake was 11.06 MJ, of which 85.4% was derived from carbohydrate. Pulmonary ventilation varied from 9.5 (pounding helper) to 26.4 (pounding alone) L/min. Maximum pulmonary ventilations in the tasks were only 27 to 31% of maximum breathing capacity. Average work pulse rate in many tasks was more than 130 beats per minute. Pounding alone or in pairs and digging dry soil are the heaviest jobs, while harvesting, transplanting, uprooting, and carrying loads are moderately heavy. Whole day energy expenditure was 10.61 MJ, of which 52% was expended for the working day, while physiological cost per unit time corresponds to 28% of V_O2max. The workloads of the females were within reasonable limits.

13. Oberoi K, Dhillon MK & Miglani SS (1983): A study of energy expenditure during manual and machine washing of clothes in India. Ergonomics, 26, 375-378

Energy expenditure while washing clothes manually and by machine was measured in 15 female students. The highest mean energy expenditure during manual washing was found when the subjects were squatting on the ground (1.72 +- 0.04 kcal.min^-2.min^-1) and the lowest mean energy expenditure was for washing while sitting on a 6.5 cm stool (patra) (1.14+-0.05 kcal.m^-2.mim^-1) and while standing at sink level (1.15 +-0.03 kcal.m^-2.min^-1), respectively. These latter values were not significantly different from those found during machine washing of clothes.

14. Panter-Brick C (1992): Women's working behaviour and maternal-child health in rural Nepal. In: Physical activity and health, edited by N.G. Norgan, pp. 190-206. Cambridge,

1 he purpose of this study was to investigate the inter-relationships between behaviours, health and physical activity and the implications of these for maternal and child health among rural Nepalese women. Measurements were made of the energy costs of load carrying, which is a regular activity for these women, while walking uphill, downhill and on level ground carrying 0-55 kg loads. Despite their habitually heavy work loads, various socio-cultural strategies allow these women to integrate economic with childbearing responsibilities.

15. Panter-Brick C (1993): Seasonality of energy expenditure during pregnancy and lactation for rural Nepali women. Am.J.Clin.Nutr. 57, 620-628.

Department of Anthropology, Durham University, UK. Total energy expenditure (TEE) was estimated for 19 nonpregnant, nonlactating (NPNL) and 24 pregnant (P) or lactating (L) women from 3601 h of minute-by-minute observation and 168 measurements of the energy cost of activities. NPNL women significantly increased subsistence activity and TEE from 9.9 MJ [1.89 x basal metabolic rate (BMR)] in the winter to 10.5 MJ (2.01 x BMR) in the monsoon season. There were differences between NPNL,P, and L women in the winter, but not in the spring or monsoon season when all individuals sustained very heavy physical activity. High TEE values resulted from spending very long hours in tasks that, although appearing physically demanding to the casual observer, were characterized by light or moderate energy cost. The study highlights the importance of seasonal constraints on women's work, which prevent P and L women from significantly curtailing physical activity during the monsoon season, and which effectively limit the scope of behavioral mechanisms for saving energy and reducing TEE.

16. Schutz Y. Lechtig A & Bradfield RB (1980): Energy expenditures and food intakes of lactating women in Guatemala. Am.J.Clin.Nutr. 33, 892-902.

Total energy expenditures and intakes were simultaneously assessed in 18 free-ranging lactating women (10 months postpartum) and compared to six similarly-sized, nonlactating, nonpregnant but multiparous women living in the same rural villages in the Guatemalan highlands. Energy intakes were estimated by the 24-hr recall method for each of 4 consecutive days. Energy expenditures were determined for 2 days by monitoring heart rate throughout the day and relating heart rate to oxygen consumption by individually-determined regression lines. The mean energy intake for the 4 consecutive days was estimated to be 1929 +/- 360 kcal/day (39.2 kcal/kg per day) for the lactating group; and 1876 +/- 404 kcal/day (38.3 kcal/kg per day) for the nonlactating group. The 2-day mean energy expenditures were estimated to be 2007 +/292 kcal/day for the lactating women (41.8 kcal/kg per day) and 1966 +/- 382 kcal/day for the lactating women (40.1 kcal/kg per day). The way of life of both groups was judged "moderately active" by 1973 FAO/WHO classifications. Most of the lactating women had been losing weight progressively during the past 6 months. Over the 10-week period prior to our measurements, the mean weight loss was more than 10 times greater in the lactating group (-369 g/month) (P < 0.01) than in the nonlactating group (-35 g/month) (ns). The high correlation (r = 0.87) between weight loss and the reduction in the sum of the three skinfolds suggested adipose tissue loss. There were no significant differences between the two groups in terms of daily energy intake, daily energy expenditure, the energy cost of specific activities throughout the day. The slope of the heart rate/oxygen consumption regressions suggest adequate cardiorespiratory fitness. This study suggests that the energy cost of lactation was met to a greater extent by fat loss than by either increased energy intake, reduced energy expenditure, or both.

17. Sen RN, Ganguli AK, Ray GG, De A & Chakrabarti D (1983): Tea-leaf plucking - workloads and environmental studies. Ergonomics, 26, 887-893.

Heart rates and energy costs of female tea-leaf pluckers in India were studied while at rest, during walking (with and without basket loads) and during plucking. Walking with loaded baskets was the most strenuous job. The 'fast' category of pluckers had higher cardiac and gross energy costs than the 'slow' category. When the energy costs were linked to productivity. The thermal load was found to be high, and the effectiveness of protective equipment such as indigenous hats has been discussed.

18. Singh J. Prentice AM, Diaz E, Coward WA, Ashford J. Sawyer M & Whitehead RG (1989): Energy expenditure of Gambian women during peak agricultural activity measured by the doubly-labelled water method. Br.J Nutr. 62, 315-329.

MRC Dunn Nutrition Unit, Cambridge. The doubly-labelled water (2H2180) method was used to measure total energy expenditure (TEE) in ten non-pregnant, non-lactating (NPNL), six pregnant (P) and fourteen lactating (L) women in a rural Gambian community. Measurements were made on free-living subjects at a period of peak energetic stress when high agricultural work loads coincided with a hungary season to induce moderately severe negative energy balance. TEE averaged 10.42 (SD 2.08) MJ/d, equivalent to 1.95 (SD 0.38) times resting metabolic rate (RMR). The energy cost of physical activity plus thermogenesis, derived as TEE-RMR, averaged 4.94 (SD 1.96) MJ/d. Expressed per kg body-weight (103 kJ/kg per d) this component of expenditure was 2.5 times greater than comparative values from inactive, affluent women studied previously (39 kJ/kg per d). Estimated energy intake (El) in a subset of the women (n 13) was only 4.80 (SD 1.58) MJ/d, yielding an apparent deficit of 6.08 MJ/d between El and TEE. Weight changes suggested that endogenous fat oxidation accounted for only about 0.85 MJ/d, leaving an unexplained difference of over 5 MJ/d. Critical analysis of possible errors suggests that the new doubly-labelled water method has provided the most reliable estimates and that the estimates of El were substantially in error. This finding has important consequences for other food intake studies.

19. Tin-May-Than (1988): Energy expenditure, duration of activities, and physical work capacities of Burmese women weavers. Food.Nutr.Bull. 10, 48-50.

This study asseses the daily energy expenditure of Burmese women weavers and concludes that, although the total energy cost of their work is considerable because of the many hours involved, it is not sufficiently intense either for substantial muscular development or for cardiovascular fitness. The weavers would not be able to tolerate work demanding high energy expenditure.

20. Torun B. McGuire J & Mendoza RD (1982): Energy cost of activities and tasks of women from a rural region of Guatemala. Nutr.Res. 2, 127-136.

The energy cost of various domestic and agricultural activities were measured by indirect calorimetry in 56 women, 16-49 years old, from a small rural village. Mean energy expenditures (kcal/kg/min) were 0.021-0.035 for fourteen activities ("light occupations"), 0.038 - 0.064 for thirteen ("moderately active" occupations) and 0.072 - 0.089 for four ("very active" occupations). There were no differences per kg of weight between pregnant, lactating and non-pregnant, nonlactating women. The results were compared with other studies and weighted averages were calculated. The values reported can be used in combination with measurements of time to estimate energy expenditure in time-motion studies.

21. Wilke NA, Sheldahl LM, Dougherty SM, Hanna RD, Nickele GA & Tristani FE (1995): Energy expenditure during household tasks in women with coronary artery disease. Am.J.Cardiol. 75, 670-674.

Zablocki Veterans Administration Medical Center, Milwaukee, Wisconsin 53295, USA. The energy expenditure for and heart rate responses to common household tasks were determined in 26 older (mean age 62 +/- 2 years) women with coronary artery disease (CAD). Each activity was performed at a self-determined pace for 6 or 8 minutes. The average oxygen uptake (ml/kg/min) for each task evaluated was 6.5 for washing dishes, 6.8 for ironing, 7.2 for scrubbing pans, 8.6 for unpacking groceries, 9.5 for vacuuming, 9.8 for sweeping, 10.1 for mopping, 12.0 for changing bed linens, and 12.4 for washing the floor (hands and knees). None of the subjects reported angina. Mean relative oxygen uptake (i.e., percentage of peak response with treadmill testing) ranged from 31 +/- 2% for washing dishes to 62 +/- 3% for changing the bed linens and washing the floor. Percentage of peak treadmill heart rate ranged from 62 +/- 2% for washing dishes to 73 +/- 2% for washing the floor. In 4 of the more physically demanding household activities (i.e., vacuuming, mopping, washing the floor, and changing bed linens), the responses of 10 age-matched normal women were evaluated. The absolute and relative demands of the tasks were similar between the CAD and normal groups. Results indicate that the mean energy expenditure rate of common household tasks evaluated in this study range from 2 to 4 METs, suggesting that most women with CAD who are able to achieve > or = 5 METs during a treadmill exercise test without adverse signs or symptoms should be able to resume these activities.

Foreign language references

1. Frauendorf H. Kohn Seyer G & Kopske J (1980): [Heart rate and energy turnover in women working in a modern industrial laundry]. Z.Gesamte.Hyg. 26, 629-631.

The pulse rate and energy turnover of ten women working in a large industrial laundry plant were measured to determine the biological effort required for operating the automatic washing machines (type 11027). The pulse rate was transmitted radio-telemetrically whilst an indirect calorimetric technique was used for measuring the energy turnover. The mean values of the working pulse rate when operating automatic washing machines (with hangers) were 45 beats (netto) per min. of the working energy turnover between 2.9 and 3.1 Akcal/min (-2.2 to 13 AkJ/min); in the case of women working on machines without hangers the mean values measured were 46 to 50 heart beats (netto) per minute and 2.9 to 2.5 Akcal/min (~12.1 to 10.5 akJ/min). The physical effort is due to changing and unloading the washer drums. The energy turnover of women working a full shift on washing machines with hangers was 1105 Akcal (4639 AkJ) (-2.0 Akcal/min or 8.4 AkJ/min), in those working on washing machines with hangers the energy turnover was 1022 Akcal (~4294 AkJ) which is equivalent to 1.8 Akcal and 7.7 AkJ per minute.

2. Frauendorf H & Kohn-Seyer G (1980): [Biological effort of women doing wholesaling operations in food warehouses using shelf-handling equipment]. Z.Gesamte Hyg. 26, 250-252.

Measurements of the heart rate and energy expenditure were carried out on 10 healthy women doing commissioning work (loading trolleys with goods parcels according to the lists containing orders from retail trade establishments) under model conditions (shelf-handling device) in a foodstuff warehouse. During the commissioning phases (about half the duration of a shift) a mean heart rate of 133 +- 20 beats/min (the working heart rate being 47 +- 11 beats/min) was observed, and the mean energy consumption at work was 3.1+- 0.9 kcal/min (=13+- 3.8 kJ/min), which is beyond the valid limit for continued physical work to which women may be exposed. But when related to the duration of the shift (without breaks) the work energy rate was about 1100 kcal (4600kJ) which corresponds to a minute value of 2.1 kcal (=8.8kJ) (range in between heavy and medium physical work).

(introductory text...)

1. Barnes RM (1973): Physical energy expenditure in long-haul cabin crew. Aerosp. Med. 44, 783-785.

A study of the physical energy expenditure of BOAC's cabin crew was carried out as a part of a workload survey. It was not considered possible to place a repirometer on a crew member during a normal commercial flight on aesthetic grounds and an indirect method of measurement was, therefore, devised. Due to the variety of duties cabin staff carry out it was necessary to analyse their working day and break it down into a number of defined tasks. Volunteers were asked to carry out these tasks in the training mock-up whilst wearing a Max Plack respirometer. From the results obtained, the subjects' energy expenditure per minute was calculated. Experiments were carried out to show that the figures obtained were equally applicable at cabin altitudes. By means of time and motion studies and questioning the cabin crew an "average working day" and a "maximum working day" were built up. The energy expenditure was then estimated. This was compared with that of other working groups. It was concluded that the physical energy expenditure of cabin crew was within acceptable limits.

2. Bilodeau B. Roy B & Boulay MR (1995): Effect of drafting on work intensity in classical cross-country skiing. Int.J.Sports Med. 16, 190-195.

Physical Activity Sciences Laboratory, Laval University, Quebec, Canada. The purpose of this study was to compare the heart rate responses during cross-country skiing as a leading skier, as well as in a drafting situation, three meters behind the leader. Eight male and two female cross-country ski racers, paired for skiing ability, skied a 2 km course (two loops of 1 km) using the diagonal stride and double-poling techniques at a fixed speed (4.75 m.s-1 and 4.45 m.s-1 for males and females respectively) on two different occasions, once as a leading skier, the other as a drafter. A recovery period of 30 minutes was allowed between the two trials. Heart rates (HR) were registered every five seconds during all performances. Results revealed that HR were significantly lower (165 vs 172 beats.min-1) when skiing behind another skier as opposed to leading. Results also revealed that projected frontal areas appeared to influence the effects of drafting such that the HR differences between the leading and the drafting situations were larger for smaller skiers drafting behind larger skiers. These results showed that skiing behind another skier in a classical cross-country ski race would be very advantageous when the situation is encountered and could help racers using this energy saving strategy.

3. Bleiberg F. Brun TA, Goihman S & Lippman D (1981): Food intake and energy expenditure of male and female farmers from Upper-Volta. Br.J.Nutr. 45, 505-515.

1. The energy balance of eleven male and fourteen female adult farmers was measured for 6 d after the harvest, in December-January. Their energy intake was recorded by weighing their food consumption and their energy expenditure was determined using indirect calorimetry. 2. Body-weight, expressed as percentage of expected weight-for-height was 91 and 86% of the Interdepartmental Committee on Nutrition for National Development (1963) standard for women and men respectively. 3. The staple foods were sorghum (Sorghum vulgare) and millet (Pennisetum typhoides); carbohydrates, fat and protein supplied approximately 80, 13 and 12% of the total energy of the diet respectively. 4. In the male group, the mean energy intake (9.0 MJ (2148 kcal)) was in good agreement with the average energy output (8.91 MJ (2130 kcal)). By contrast, in the female group, the mean energy expenditure (8.11 MJ (1941 kcal)) exceeded the mean energy intake (6.3 MJ (1515 kcal)) and the deficit was statistically significant. 5. This study allows an evaluation of the adequacy of food intake for subjects living in a particular hostile environment, by using their actual energy output instead of current standard values. The energy deficit found for female farmers whose energy intake was similar to that reported in other developing countries emphasizes the need for a better understanding of the regulation of energy balance in such conditions.

4. De Guzman PE, Cabrera JP, Yuchingtat GP, Abanto ZU & Gaurano AL (1984): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups 11. Laguna rice farmers. Philip.J.Nutr. 37, 163-174.

The total energy expenditure and dietary intake of nine male and nine female rice farmers in Barrio Pansol in Pila, Laguna, an area of the Philippines where rice is the main agricultural crop, were determined for one week each during different periods in the agricultural diary. These were land preparation, planting, weeding and harvesting, and also the off-farming period. The energy costs of specific activities carried out during these periods were measured via indirect calorimetry. Total energy expenditure was calculated using the factorial method of Durnin of Brockmore using these values and additional values from published tables. A seven day diary was used to calculate energy intakes. There were significant differences in the energy expenditure of both male and female farmers between the different periods but not in energy intakes. Intake was significantly less than expenditure during all periods except the off-farming. The mean daily energy expenditure of the male farmers during the year was approximated to be 2977 kcal or 12,456 kJ and mean daily intake was 2708 kcal or 11,330 kJ. The females had a mean energy expenditure of 2181 kcal or 9125 kJ and mean intake of 1807 kcal or 7560 kJ. Although energy intake was less than energy expenditure for both male and female farmers, the difference was statistically significant only in the female farmers. When compared to the recommended dietary allowances, the mean energy intake of the male farmers may be considered adequate because it represented 107% of the RDA. The mean energy intake of the female farmers was lower and represented only 97% of the recommended level. These differences, however, were not statistically significant. With reference to the FAO/WHO recommendation, both male and female farmers can be classified as moderately active. A study of the pattern and variation in the work activities throughout the year showed that the male farmers were found to engage in non-farming activities for approximately 44% of the year while the rest of the time was spent performing agricultural activities. The female farmers engaged in non-farming activities for a longer period (64%) and spent only 36% of the year doing farming activities. Differences in energy expenditure and intake and also body weight between the different periods of farm activity were mostly not statistically significant. The results of this study indicate that energy balance in these subjects was achieved over a long period of time, rather than on a daily or even monthly basis.

5. De Guzman PE, Cabrera JP, Basconcillo RO, Gaurano AL, Yuchingtat GP, Tan RM, Kalaw JM & Recto RC (1978): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. V. Clerk-Typist. Philip.J.Nutr. 31, 147-156.

The energy expenditure, dietary intake and activity patterns of ten male and ten female clerks and typists, a major occupational group in The Philippines, were examined. The energy cost of common occupational activities was measured using a Max Planck respirometer. Subjects kept an activity diary and total energy expenditure was calculated by the factorial method of Durnin and Brockway using the original measurements of energy costs and data from published tables. Values obtained for the metabolic cost for the basic activities expressed in calories per kilogram per minute indicated differences in mean energy costs between sexes when sitting and standing. The F-ratio obtained was not significant in testing the null hypothesis that walking has the same energy cost for male and females. Mean values obtained for the daily protein, fat, carbohydrate, and total energy intake of each subject more or less approximated the percentage calorie distribution in the eight regions surveyed in the Philippines. F-tests to compare the means of total energy intake and expenditure for the two sexes indicated no significant differences in the total energy intakes of the two groups. However, there was evidence to conclude that the male group had higher total energy expenditure than the female group. It was also observed that when weight was considered as a normalizing factor, the differences in expenditure difference between the two sexes were no longer significant. The clerks and typists studied based on the joint FAD/WHO recommendations on energy expenditure can be classified as lightly active to very lightly active.

6. De Guzman PE, Dominguez SR, Kalaw JM, Buning MN, Basconcillo RO & Santos VF (1974): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups. ll. Markina shoemakers and housewives. Philip.J.Nutr. 27, 21-30.

This study is the second of a series on occupational activities of-Filipinos. The first study was made on rice farmers (1). The subjects for the study include 10 shoemakers and 10 housewives in the municipality of Markina, province of Rizal, where the shoemaking industry is concentrated. The same methodology was used as in the previous study wherein one week data on the energy expenditure of each subject was measured by indirect calorimetry while performing their usual daily activities. Time spent and the mean daily food intake of the subjects were likewise measured during the same period.

7. De Guzman PE, Recto RC, Cabrera JP, Basconcillo RO, Gaurano AL, Yuchingtat GP & Abanto ZU (1979): A study of the energy expenditure, dietary intake and pattern of daily activity among various occupational groups VI. Textile mill workers. Philip.J.Nutr. 3, 134-148.

Twenty-five male and fourteen fen-ale textile workers were studied to determine their pattern of daily activity, dietary intake, and energy expenditure. The energy costs of basic and occupational activities were measured by indirect calorimetry. Values obtained for sitting, standing and walking among the males did not differ significantly from those of the females. Univariate analysis was used to compare these values with data previously collected on other occupational groups. No signifcant F-ratio was obtained indicating that the sampled subjects from the different groups have comparable energy expenditure for these basic activities. Analysis of the differences between men and women in energy costs of different activity types in the textile production process showed that men expended significantly more energy than women in spinning and weaving. The mean daily energy expenditure for the males was 2,494 kcal and for the females, 2,024 kcal. These values were significantly high compared with their mean daily energy intake of 2,339 kcal and 1,510 kcal, respectively. The textile mill workers can be classified as lightly active to moderately active with reference to the FAO/WHO recommendations.

8. Edholm OG, Humphrey S. Lourie JA, Tredre BE & Brotherhood J (1973): VI. Energy expenditure and climatic exposure of Yemenite and Kurdish Jews in Israel. Philos.Trans.R.Soc.Lond.Biol. 266, 127-140.

The daily energy expenditure of Yemenite and Kurdish Jews has been assessed in summer and winter. The majority of the male subjects were engaged in farming; the women were mainly housewives. A timed activity survey was carried out on all subjects. The differences between summer and winter were, in general, small and the time spent by the men in different activities averaged for the two seasons were, for the Yemenite Jews, 7.69 h Lying, 7.16 h sitting, 7.6 h working. The Kurdish Jews spent 8.44 h Lying, 6.4 h sitting and 7.4 h working. Energy expenditure was computed from the timed activity survey and measurements of oxygen consumption in a number of tasks. The energy expenditure of the men in the summer was 3050 kcal (12760kJ) per day for both the Yemenite and Kurdish Jews. In the winter, the Yemenite Jews expended 3000 kcal (12560kJ) and the Kurdish Jews 3110 kcal (13020 kJ) per day. The Yemenite Jewish women expended 2280 kcal (9550kJ) per day in the summer and 2400 kcal (10040 kJ) per day in the winter, and the Kurdish Jewish women expended 2250 (9420 kJ) per day in the summer and 2390 kcal (10000kJ) per day in the winter. Integrated heart rates were recorded in the two seasons, during the night and during the day. The night rates were significantly lower in the summer than in the winter. The average night rates (beats/min) in summer and winter respectively were: Kurdish Jews, men 56.3 and 60.9, women 63.0 and 70.6; Yemenite Jews, men 60.4 and 65.6, women 66.6 and 70.5. The time spent out of doors in the daylight hours was 348 min/day in the summer and 347 min/day in the winter for the Yemenite Jewish men. The Kurdish Jewish men spent 401 min/day out of doors in the summer and 342 min/day out of doors in the winter. The Yemenite Jewish women were out of doors for 205 min/day in the summer and 243 min/day in the winter. The corresponding figures for the Kurdish Jewish women were 203 and 81 min/day.

9. Edmundson WC & Edmundson SA (1989): Energy balance, nutrient intake and discretionary activity in a South Indian village. Ecol.Food Nutr. 22, 253-265.

The energy balance and discretionary activity of eight male and eight female South Indian farmers was carefully measured for four days in 1983. The women, who were small and had low energy intakes, expended far more time on work than the males. Height and weight for male subjects averaged 161.0 cm and 48.2 kg. The women were 148.8 cm tall and weighed only 36.9 kg. Women were able to perform the 15 work tasks at lower cost than men primarily because they were smaller. In males the mean energy intake was 9.83 MJ (2350 kcal). The females' mean energy intake was 7.73 MJ (1852 kcal). The average energy intake was 7.73 MJ (1852 kcal). The average energy intake per unit mass was equal for both sexes at 22 kJ (50 kcal) per kg. Women allocated more time to economically productive work (46.2% or 11.1 hours versus 33.9% or 8.1 hours). There was no significant correlation between an individual's energy intake and time spent working (r=-.24). There was no association between intake and energy expended on economically productive tasks (r=.02). Both social and physiological processes enable women and others on a low plane of nutrition to maintain a high level of productivity.

10. Evans WJ, Winsmann FR, Pandolf KB & Goldman RF (1980): Self-paced hard work comparing men and women. Ergonomics, 23, 613-621.

Six fit male subjects (23 years, 171 cm, 67 kg, maximal VO2=2.25 mmol.kg-1.min-1 (50.3 ml.kg1.min-1) and six fit female subjects (22 years, 163 cm, 57 kg, maximal VO2=1.83 mmol.kg1.min-1 (41.1 ml.kg-1.min-1) performed self-paced hard work while walking over four different terrains carrying no external load, 10 kg and 20 kg. Time on each course for individual subjects was used to determine speed and energy expenditure; heart rate was recorded as each subject completed each course. Walking speed and energy expenditure of the males were found to be significantly greater (p<0.05) than those of the females over all terrains (blacktop road, 1.6 km; dirt road, 1.8 km; light brush, 1.4 km; and heavy brush, 1.3 km) and for each load carriage condition. Relative energy expenditures of the males and females for all conditions were very similar (p>0.05) and remarkably constant at a value close to 45% VO2max These data indicate that the voluntary hard work rate is dependent upon maximal aerobic power. The best predictor of speed for self-paced hard work of males and females for 1 to 2 hours in duration appears to be based on 45% of maximal aerobic power.

11. Fordham M, Appenteng K, Goldsmith R & O'Brien C (1978): The cost of work in medical nursing. Ergonomics, 21, 331-342.

The physiological cost of work was measured on the nursing staff of a general medical ward. Fourteen subjects took part in the study. Heart rates were measured during work and sleep on 13 nurses, and oxygen consumption measurements were made on 12, using the Miser Respirometer. In addition, maximum aerobic capacity was estimated on eight of the subjects. Mean heart rates during work were 93 +- SD 10 bt.min-1, significantly higher on the late than on the early shift. The mean rate of energy expenditure was 147 +- SD 31 W. and was significantly higher in the morning than the afternoon or the evening. The mean relative work load was 22% +SD 5%. The mean individual relative heart rate was 26% +- SD 9% and the mean ratio of work:sleep heart rate was 1.45 +- SD 0.19. The findings placed medical nursing in the same category as light work.

12. Montgomery E & Johnson A (1977): Machiguenga energy expenditure. Ecol.Food Nutr. 6, 97-105.

This article presents the results of a study of energy expended at typical activities and on average days, by adult women and men of a hunter-gatherer-horticulturalist population in southeastern Peru. Marked differences between the sexes in patterns of energy use are presented. The men tended to work at higher rates of energy expenditure than did the women. On the average day, representatives of all activities in an annual cycle, the women expended about 8.0 MJ (1925 Cals) whereas the men expended about 13.3 (3200 Cals). Seasonal analysis reveals an even greater contrast during the wet months. Relations between the Machiguenga and their upper Amazonian rain forest environment are considered in accounting for the observed patterns of energy expenditure. Factors such as differences in uses of technology, work settings, and population composition are related to the findings.

13. Norgan NG, Ferro-Luzzi A & Durnin JVGA (1974): The energy and nutrient intake and the energy expenditure of 204 New Guinean adults. Philos.Trans.R.Soc.Lond.Biol. 268, 309-348.

Two village populations, Kaul in a coastal region and Lufa in a highland region, were each studied for 9-10 months. Measurements of food intake and total daily energy expenditure were made on individual subjects, 51 men and 69 women in Kaul and 43 men and 41 women in Lufa. Each individual was investigated during a period of 5-7 consecutive days. The way of life for all the people was moderately active - more so in the highlands - since they were subsistence farmers cultivating their own gardens for food. The mean daily energy intakes were 8.12 MJ (1940 kcal) for the Kaul men, 10.55 MJ (2520 kcal) for the Lufa men, 5.95 MJ (1420 kcal) for the Kaul women and 8.81 MJ (:2105 kcal) for the Lufa women. There were almost no differences in the energy intakes of the non-pregnant non-lactating, the pregnant and the lactating women in each village. The intakes of protein were low, providing 6.7, 6.0, 6.5 and 7.2% of the energy value of the diets of the Kaul men and women and the Lufa men and women respectively. Fat provided only about 10% of the energy in the highland diet and 17% in the coastal diet. Age and body mass showed surprising relationships with energy intake. Although most of the energy and protein in the diets came from the staple vegetable (taro in Kaul and sweet potato in Lufa), this was less so than in previous studies. A total of 1160 measurements of energy expenditure were made on various activities in the individual people and mean values are given for these activities. The pattern of daily energy expenditure is also shown. Lying, sitting and standing accounted for about 70% of the total day and 60% of the total energy expenditure. Walking occupied about 10% of the 24h and between 20 and 27% of the energy output. Some of the results of food intake, particularly on the women in the coastal region, are very difficult to explain on currently accepted grounds.

14. Nyunt-Khin, Hla-Win & Tin-May-Than (1968): Energy expenditure in agricultural activitities in Burma. Union of Burma Journal of Life Sciences, 1, 359-363.

The energy expenditure of 21 men and 8 women from the villages of Chitteegonein the Mingaladon area and Danyingone in the Inssein area was studied during paddy cultivation. Three subjects who were typical farmers were chosen for recording daily activities intermittently throughout the year using the diary technique of Garry, Passmore, Warnock and Durnin (1955). The mean daily energy expenditure of these subjects during various agricultural seasons was calculated. The mean metabolic cost kcal/min/subject was determined on the above subjects and more than one determination were made on some individuals. The validity of the assessed metabolic cost for use in future energy expenditure for paddy cultivation was proved and found to be satisfactory.

15. Panter-Brick C (1992): The energy cost of common tasks in rural Nepal: levels of energy expenditure compatible with sustained physical activity. Eur.J.Appl.Physiol 64, 477-484.

Department of Anthropology, Durham University, UK. Three hundred and six measurements of energy expenditure by indirect calorimetry of sitting at rest and self-paced activity were made on 41 men, 48 women and 6 adolescents in a mountain village of Nepal. Except for walking and carrying uphill, measured activities fell within the range of values for light to moderate effort, despite appearing physically demanding. Villagers tended to reduce travel speed when carrying heavy loads (54-102% of body mass on various inclines), averaging a moderate level of energy expenditure which could be sustained throughout the day. Such moderately demanding work was also assumed by pregnant, lactating women and young adolescents. Pregnant women worked more slowly at some tasks, but did not differentiate themselves from their non-pregnant, non-lactating counterparts for travel on the mountain side.

16. Stauffer RW, McCarter M, Campbell JL & Wheeler LF, Jr. (1987): Comparison of metabolic responses of United States Military Academy men and women in acute military load bearing. Aviat.Space Environ.Med. 58, 1047'-1056.

Exercise Science Laboratory, United States Military Academy, West Point, New York 10996. Twenty-four first year United States Military Academy (USMA) men and women were studied to compare metabolic response differences in seven horizontal walking velocities, under three military load bearing conditions. The treadmill protocol consisted of walking or jogging on a horizontal treadmill surface for 3-rein intervals at velocities of 3, 3.5, 4, 4.5, 5, 5.5, and 6 mph.

The three military load bearing conditions weighed 5, 12, and 20 kg. Metabolic measurements taken at each speed in each of the military load bearing conditions were: minute volume, tidal volume, respiratory rate, absolute and relative to body weight oxygen consumption, and respiratory quotient. Two three-way analyses of variance for repeated measures tests with main effects of gender, military load, and speed revealed that USMA men and women metabolically respond to different military load bearing conditions; they metabolically respond to different walking and jogging velocities under military load bearing conditions; and they have identifiable and quantifiable metabolic response differences to military load bearing. This study was designed to improve USMA physical and military training programs by providing information to equally and uniformly administer the USMA Doctrine of Comparable Training to men and women alike; and additionally to clarify the "...minimal essential adjustments...required because of physiological differences between male and female individuals ..." portion of Public Law 94106 providing for the admission of women to America's Service Academies.

17. Yoshioka T. Narusawa M, Nagami K, Yabuki C, Nakahara Y. Nakano S. Sekiguchi C, Noda K, Nagai T. Kobayashi Y. Kobayashi K, Ohmori K, Sakai T & Furusato M (1982): Effects of relative metabolic rate and heart rate variation on the performance of flight attendants. Aviat.Space Environ.Med. 53, 127-132.

The main work of the cabin attendants in an actual flight is service for passengers. The effects of flight attendant duties in flight differ from the effects of the same tasks performed on the ground. In this study, the relative metabolic rate (RMR) and heart rate (HR) of cabin attendants in a cruising aircraft galley and cabin are compared with those of a crew working in a mock-up apparatus on the ground. The types of work tested are: (a) oshibori (steamed towel) service, (b) soft drink service, (c) setting meal tray, (d) putting casserole on tray, (e) meal tray service, (f) walking on aisle. The RMR at each type of work during flight is as indicated: (a) 1.07-2.10, (b) 1.08-1.54, (c) 1.37-1.82, (d) 2.57-3.50, (e) 2.11-3.10 and (f) 1.84. The range of HR was: (a) 105-120, (b) 90-110, (c) 90-120, (d) 100-130 and 100-140 beats/mint In most cases, the RMR and HR levels of work done in the mock-up were lower than those recorded in flight. These results suggest that the oxygen intake of work done in flight is greater than that on a mock-up. One of the reasons might be that the cabin barometric pressure (ca. 660 torr or cabin altitude cat 1,500 m) or an aisle inclination of about 3 degrees caused a decrease in the efficiency of oxygen intake during flight.

Foreign language references

1. Maune R & Ketz HA (1968): [Measurements of energy consumption in workers of different job groups when sitting, standing and walking both without strain and while carrying out their work]. Ernahrungsforschung, 13,1-51.

This is a report on the results of investigations in which the so-called basic activities of sitting, standing and walking without strain and work activity were measured in men and women in industry by means of indirect calorimetry. The methodology is based on the use of respiration gas meters, the portable "Spirolyt" instrument for testing performance and a nomographical calculation of the results. The average values of all the job groups examined are given as kcal/min/kg with relevant s-values and s=% of x. The results show statistically significant differences between men and women for the basic activities with the values for energy expenditure values for women being lower than those for men. [not original abstract].

4.3.1 Men

1. Adrian MJ, Singh M & Karpovich PV (1966): Energy cost of leg kick, arm stroke, and whole crawl stroke. .J.Appl.Physiol 21,1763-1766.

The net energy costs of the leg kick, arm stroke and whole stroke of the crawl were determined and formulas for the calculation of oxygen requirement derived. Results showed that for a given speed the energy cost of the leg kick was two to four times greater than that of the arm stroke and whole stroke. The energy cost of the arm stroke was less than that of the whole stroke up to a velocity of 3.35 ft/sec. The formulas for oxygen consumed per minute derived from test on the best swimmer are: 02 for the legs = 1.32 V^2,05; 02 for the arms = V^3,95/20.42; and 02 for the whole stroke = V^2,70/4,38 (V= velocity, ft/sec). The energy cost given here pertains to actual swimming and not to conventional swimming, which consists not only of swimming but of a dive and push-offs which inflate the so-called average velocity. The efficiency of the leg kick ranged from 0.05-1.23%, whereas the arm stroke ranged from 56-6.92%. The efficiency of the whole stroke was slightly higher than that reported in other studies and ranged from 1.71-3.99%. Results obtained substantiate opinions of swimming coaches that in long-distance crawl the leg action should be reduced to a minimum.

2. Boyle PM, Mahoney CA & Wallace WF (1994): The competitive demands of elite male field hockey. J.Sports Med.Phys.Fitness. 34, 235-241.

Physical and Health Education Unit, Queen's University of Belfast, Northern Ireland. To establish the energy cost of competitive field hockey, nine international hockey players wore a modified Sport Tester PE3000 telemetric heart rate monitor during matchplay and also completed a laboratory based incremental treadmill test to establish maximal oxygen uptake VO2max The heart rate data from competition were compared with heart rate and oxygen uptake data measured in the laboratory. Individual regression equations were established from these data to estimate the energy expenditure during competitive match-play. The mean heart rate during competition was 159 +/- 8 beats/min (mean +/- SD). The mean estimated oxygen uptake during competition was 48.2 +/- 5.2 ml/kg/min which is commensurate with 78% of the group's mean maximal oxygen uptake of 61.8 +/- 1.8 ml/kg/mint The mean estimated energy expenditure throughout an entire match was 5.19 MJ and rates of energy expenditure ranged from 83 kJ/min for the centre midfield position to 61.1 kJ/min for the left corner forward position. This study has shown the feasibility of heart rate monitoring as a means of estimating energy expenditure in elite hockey. Competitive matches place a heavy demand on the aerobic system and require players to expend energy at relatively high levels.

3. Brueckner JC, Atchou G. Capelli C, Duvallet A, Barrault D, Jousselin E, Rieu M & di Prampero PE (1991): The energy cost of running increases with the distance covered. Eur.J.Appl.Physiol 62, 385-389.

Department of Physiology, CMU, Geneva, Switzerland. The net energy cost of running per unit of body mass and distance (Cr. ml O2.kg-1.km-1) was determined on ten amateur runners before and immediately after running 15, 32 or 42 km on an indoor track at a constant speed. The Cr was determined on a treadmill at the same speed and each run was performed twice. The average value of Cr. as determined before the runs, amounted to 174.9 ml O2.kg-1.km-1, SD 13.7. After 15 km, Cr was not significantly different, whereas it had increased significantly after 32 or 42 km, the increase ranging from 0.20 to 0.31 ml O2.kg-1.km-1 per km of distance (D). However, Cr before the runs decreased, albeit at a progressively smaller rate, with the number of trials (N), indicating an habituation effect (H) to treadmill running. The effects of D alone were determined assuming that Cr increased linearly with D, whereas H decreased exponentially with increasing N. i.e. Cr = Cr0 + a D + He-bN. The Cr0, the "true" energy cost of running in nonfatigued subjects accustomed to treadmill running, was assumed to be equal to the average value of Cr before the run for N equal to or greater than 7 (171.1 ml O2.kg-1.km-1, SD 12.7; n=30). A multiple regression of Cr on N and D in the form of the above equation showed first, that Cr increased with the D covered by 0.123%.km-1, SEM 0.006 (ie about 0.22 ml 02.kg-1 per km, P<0.001); second, that in terms of energy consumption (obtained from oxygen consumption and the respiratory quotient), the increase of Cr with D was smaller, amounting on average to 0.08%.km (0.0029 J.kg-1.m-1, P<0.001); and third that the effects of H amounted to about 16% of CrO for the first trial and became negligible after three to four trials.

4. Capelli C, Rosa G. Butti F. Ferretti G. Veicsteinas A & di Prampero PE (1993): Energy cost and efficiency of riding aerodynamic bicycles. Eur.J.Appl.Physiol 67, 144-149.

Dipartimento di Scienze e Tecnologie Biomediche, Sezione di Fisiologia, Udine, Italy. Traction resistance (Rt) was determined by towing two cyclists in fully dropped posture on bicycles with an aerodynamic frame with lenticular wheels (AL), an aerodynamic frame with traditional wheels (AT), or a traditional frame with lenticular wheels (TL) in calm air on a flat wooden track at constant speed (8.6-14.6 m.s-1). Under all experimental conditions, Rt increased linearly with the square of air velocity (v2a); r2 equal to greater than 0.89. The constant k = delta Rt/delta v2a was about 15% lower for AL and AT (0.157 and 0.155 N.s2 x m-2) than for TL bicycles (0.184 N.s2 x m-2). These data show firstly, that in terms of mechanical energy savings, the role of lenticular wheels is negligible and, secondly, that for TL bicycles, the value of k was essentially equal to that found by others for bicycles with a traditional frame and traditional wheels (TT). The energy cost of cycling per unit distance (Cc, J.m-1) was also measured for AT and TT bicycles from the ratio of the 02 consumption above resting to speed, in the speed range from 4.7 to 11.1 m.s-1. The Cc also increased linearly with v2a, as described by: Cc = 30.8 + 0.558 v2a and Cc = 29.6 + 0.606 v2a for AT and TT bicycles. Thus from this study it would seem that AT bicycles are only about 5% more economical than TT at 12.5 m.s-1 the economy tending to increase slightly with the speed. Assuming a rolling coefficient equal to that observed by others in similar conditions, the mechanical efficiency was about 10% lower for aerodynamic than for conventional bicycles, amounting to about 22% and 25% at a speed fo 12.5 m.s-1. From these data it was possible to calculate that the performance improvement when riding aerodynamic bicycles, all other things being equal, ought to be about 3%. This compares favourably with the increase of about 4% observed in world record speeds (over distances from 1 to 20 km) after the adoption of new bicycles.

5. Chatard JC, Lavoie JM & Lacour JR (1990): Analysis of determinants of swimming economy in front crawl. Eur.J.Appl.Physiol 61, 88-92.

Laboratoire de Physiologie, GIP Exercice, Faculte de Medecine, Saint-Etienne, France. The purpose of this study was to investigate the relationship between swimming economy, energy cost to move the body per unit distance (CS) at a given velocity (v) and the potential determinants, i.e. performance level, body size, swimming technique and v. A total of 101 males were studied. Three performance levels (A, B. C) were determined, ranging from the slower (A) to the faster times (B. C). At level C and at 1.1 m.s- 1, CS 1.1, was reduced by 55% and 25% when compared with levels A and B and when calculated per unit of surface area (SA) and unit of hydrostatic lift (HL). For the whole group of swimmers, CS 1.1 = 21.88 SA-2.15 HL + 5.9 (r = 0.56, P less than 0.01). Among the 101 swimmers, three other groups were selected to evaluate specifically the influence of arm length and swimming technique on CS, i.e. arm or leg swimmers and sprinters versus long-distance swimmers. CS was significantly (P less than 0.05) lower for long-arm swimmers, arm and long-distance swimmers than for short-arm, leg and sprint swimmers by 12%, SD 3.3%, 15%, SD 3.8% and 16.5%, SD 3%, respectively. For all groups, CS increased with v on average by 10% every 0.1 m.s-1. It is concluded that technical ability cannot be interpreted directly from CS. Performance levels, body size, swimming technique and v at which the measurements are obtained must be also taken into account.

6. di Prampero PE, Cortili G. Celentano F & Cerretelli P (1971): Physiological aspects of rowing. .J.Appl.Physiol 31, 853-857.

Heart rate, O2 uptake and lactic acid production together with the mechanical work performed have been investigated in man a) during simulated rowing in a basin and b) during actual rowing on a racing shell. Heart rate and 02 uptake are linearly correlated, the relationship being substantially the same for both simulated and actual rowing as for other forms of exercise. Pulmonary ventilation determined in simulated rowing is a linear function of VO2, the energy taken up by the muscles per liter of expired air being 0.26 ± 0.027 kcal. The mechanical efficiency is lower in simulated (0.1) than in actual (0.18) rowing at low stroke frequencies (<25).

It approaches in both cases a maximal level of 0.2-0.23 at high frequencies (35/min). During actual rowing the mechanical power output necessary to maintain the boat progression as well as the energy expenditure appear to increase as the 3.2 power function of the average speed.

7. di Prampero PE, Cortili G. Mognoni P & Saibene F (1976): Energy cost of speed skating and efficiency of work against air resistance. .J.Appl.Physiol 40, 584-591.

The energy expenditure during speed ice skating (P_B=650 mmHg; T=-5 degrees C) was measured on 13 athletes (speed range: 4-12 m/s) from VO₂ and (for speeds greater than 10 m/s) from blood lactic acid concentration. The energy spent (O₂ equivalents) per unit body wt and unit distance (E_tot/V, ml/kg.min) increases with the speed (v, m/s): E_tot/v=0.049 + 0.44 X 10 _-3 V₂. At 10 m/s, V_tot/V amounts then to 0.093 ml/kg-m: about half the value of running. The constant 0.049 ml/kg-m is interpreted as the energy spent against gravitational and inertial forces. The term 0.44 X 10 _-3 V₂ indicates the energy spent against the wind, the constant 0.44 X 10 _-3 ml.s₂.kg_-1m_-3 being a measure of k/e, where k is the coefficient relating drag to v2, and e the efficiency of work against the wind. From a direct estimate of k in a wind tunnel, e was calculated as 0.11. In running, skating, and cycling k/e is similar (approximately 0.020 ml.s₂.m_-3 per m2 body area), hence at a given speed the energy spent against the wind is equal. On the contrary, the energy spent against other forces decreases in the above order: 0.19, 0.05, 0.018 ml.m_-1, per kg body wt. This explains the different speeds attained in these exercises with the same power output.

8. di Prampero PE, Pendergast CR, Wilson DW & Rennie DW (1974): Energetics of swimming in man. .J.Appl.Physiol 37,1-5.

Body drag, Db, and mechanical efficiency, e, during actual swimming were measured by a new method on 10 men swimming the overarm crawl at velocities, v, of 0.55 and 0.9 m.s^-1 in a 60 -m-circumference annular pool. Db measured during swimming was double that for passive towing, as was e. The ratio, e/Db, was observed to be the same for a given individual at the two velocities, averaging 0.8 kg^-1 X 10^-2, but varied from 0.42 to 1.05 kg^-1 X 10^-2 among individuals. It can be shown theoretically that v = VO2net X (e/Db) for aerobic swimming; hence the ratio e/Db establishes the velocity a person can achieve for a given VO2net and is an index of individual proficiency in swimming. The reciprocal of e/Db is equivalent to VO2/v, e.g., the energy cost of swimming 1 m. This proved to be independent of the two velocities studied and averaged 58.5 ml O2.m^-1, about four times the cost of running for men of this size. The basic approach and the quantitative analysis of swimming proficiency in terms of the ratio e/Db have promise for the study of many forms of locomotion on or under the water surface.

9. Getchell LH (1968): Energy cost of playing golf. Arch.Phys.Med.Rehabil. 49, 31-35.

Indirect calorimetric procedures using a portable dry gas meter were used to determine the caloric cost of playing golf under foursome conditions. Four middle-aged men were tested in selected golf tasks in conjunction with a time-motion analysis and in the playing of three holes of golf. The rate of 3.7 cal per minute (3.3 cal per kilogram per hour) was determined as the caloric cost of playing golf. The results of this study suggest that the accepted value of 5 cal per minute (4.8 cal per kilogram per hour) for golf is possibly too high for foursome playing conditions.

10. Gray GL, Matheson GO & McKenzie DC (1995): The metabolic cost of two kayaking techniques. Int.J.Sports Med. 16, 250-254.

Allan McGavin Sports Medicine Centre, University of British Columbia, Vancouver, Canada. A common technique employed in flatwater kayak and canoe races is "wash riding", in which a paddler positions his/her boat on the wake of a leading boat and, at a strategic moment, drops off the wake to sprint ahead. It was hypothesized that this manoeuver was energy efficient, analogous to drafting in cycling. To study this hypothesis, minute ventilation (VE), heart rate (HR) and oxygen consumption (VO2) were measured in 10 elite male kayak paddlers (age = 25 +/- 6.5 yrs, height = 183.6 +/- 4.4 cm, mass = 83.9 +/- 6.1 kg) during steady-state exercise at a standardized velocity in conditions of "wash riding" (WR) and "non-wash riding" (NWR). The data were collected in field conditions using a portable telemetric metabolic system (Cosmed K2). Statistical analysis of the mean values for VE, VO2 and HR was performed using the Hotelling's T2 statistic and revealed significant (p < 0.05) differences between the WR and NWR trials for all three dependent variables. Mean values for VE (I/min) were WR = 113 +/- 16.5, NWR = 126.3 +/-15.7; for VO2 (I/min) were WR = 3.22 +/- 0.32, NWR = 3.63 +/- 0.3; and for HR (bpm) were WR = 167 +/- 9.9, NWR = 174 +/- 8.0. It was concluded that wash riding during kayak paddling confers substantial metabolic savings at the speeds tested. This has implications for the design of training programs and competitive strategies for flatwater distance kayak racing.

11. Hoffman MD & Clifford PS (1990): Physiological responses to different cross country skiing techniques on level terrain. Med.Sci.Sport Exerc. 22, 841-848.

Department of Physical Medicine, Medical College of Wisconsin, Milwaukee. This study compared the physiological responses and ratings of perceived exertion elicited by several of the most common currently used cross country skiing techniques. The comparison included two classical techniques (kick double pole and diagonal stride), two ski skating techniques (V1 skate and marathon skate), and the double pole technique on both classical and skating skis. Eight male cross country ski racers skied each technique for three laps around a 420 m flat, professionally groomed and tracked oval surface at a mean (+/- SD) velocity of 14.2 +/- 0.6 km.h-1. Heart rate was recorded by telemetry and expired gases were collected for determination of minute ventilation and oxygen consumption during the final minute of each bout. Rating of perceived exertion was requested immediately after each bout. It was found that the diagonal stride technique required the highest oxygen consumption, with the V1 skate, marathon skate, and kick double pole techniques inducing a 16% lower (P less than 0.01) oxygen cost, and the double pole technique inducing a 26% lower (P less than 0.01) oxygen cost. Heart rate was also highest (P less than 0.01) with the diagonal stride technique and lowest with the double pole technique. The rating of perceived exertion was greatest (P less than 0.05) for the diagonal stride technique and lowest (P less than 0.05) for the V1 skate technique. These results indicate that the double pole technique has the greatest economy, the diagonal stride technique elicits the greatest physiological demands and has the highest perceived effort, and the V1 skate technique is associated with the lowest perceived effort under the conditions of this study.

12. Hoffman MD, Clifford PS, Foley PJ & Brice AG (1990): Physiological responses to different roller skiing techniques. Med.Sci.Sport Exerc. 22, 391-396.

Department of Physical Medicine, Medical College of Wisconsin, Milwaukee. This study compared the physiological responses during roller skiing with the V1 skate, kick double pole, and double pole techniques. Eight male nordic ski racers roller skied over a flat one-mile track at 14 and 18 km.h-1 using each of the three techniques under study. Heart rates and oxygen uptakes were measured during the last minute of each bout, ratings of perceived exertion were requested immediately after each bout, and capillary blood lactate concentrations were determined 3 min after each bout. The double pole technique was found to be significantly more economical (P less than 0.05) than the other techniques, as demonstrated by a 12% lower oxygen consumption. No differences were found between the V1 skate and the kick double pole techniques for any of the variables studied. The findings of similar physiological responses with the V1 skate and kick double pole techniques suggest that these techniques should induce similar cardiovascular adaptations when roller skiing at the same speed on flat terrain.

13. Holmer I (1974): Energy cost of arm stroke, leg kick, and the whole stroke in competitive swimming styles. Eur.J.Appl.Physiol 33,105-118.

In male elite swimmers V_O2 at a given velocity in freestyle and back-stroke was on average 1 to 21 x min-1 lower as compared with breaststroke and butterfly. Except for breaststroke, swimming with arm strokes only demanded a lower VO2 at a given submaximal velocity than the whole stroke. In freestyle and backstroke the submaximal V^O2 of leg kick at a given velocity was clearly higher than the whole stroke. The highest velocity during maximal swimming was always attained with the whole stroke, and the lowest with the leg kick, except for breast stroke, where the leg kick was most powerful. At a given submaximal V_O2, heart rate and V_E V_O2 tended to be higher during swimming with arm strokes only as compared with the whole stroke. Highest values for V_O2, heart rate and blood lactate during maximal exercise were almost always attained when swimming the whole stroke, and lowest when swimming with arm strokes only. At higher velocities body drag was 0.5 to 0.9 kp lower when arms or legs were supported by a cork as compared with body drag without support.

14. Hunter GR, Montoye HJ, Webster JG, Demment R. Ji LL & Ng A (1989): The validity of a portable accelerometer for estimating energy expenditure in bicycle riding. J.Sports Med.Phys.Fitness, 29, 218-222.

The purpose of the investigation was to determine the validity of a portable vertical accelerometer and a Large-Scale Integrated Motor Activity Monitor (LSI) for estimating energy expenditure in riding a bicycle at various velocities. Instrument placement was either at the knee or ankle. Energy consumption, i.e. oxygen consumption VO2 was determined during bicycle rides after steady state metabolism was reached. Standard errors of estimate were used to express the accuracy of estimating VO2 from accelerometer or LSI recordings. The reliability of the vertical accelerometer was found to be satisfactory. The vertical accelerometer was also effective for estimating VO2 in bicycling (standard errors of estimate = 3.3 to 4.4 ml.kg-1.min-1). The accuracy of the LSI was not as good; the standard errors of estimate being = 5.9 to 8.5 ml.kg1.min-1.

15. Jette M, Mongeon J & Routhier R (1979): The energy cost of rope skipping. J.Sports Med.Phys.Fitness, 19, 33-37.

This study was designed to measure the energy cost of different intensities of rope skipping for the purpose of exercise prescription. Five male subjects between the ages of 22 to 39 participated in the study. Expired air for gas analysis was collected during simulated intervals of rope skipping periods. The net energy cost in kcal/hr per kg were as follows: level A (66 tpm (turns per minute), one foot skip, plain bounce): 10.61; level B (66 tpm, one foot skip, rhythm bounce): 9.89; level C (66 tpm, two-feet skip, plain bounce): 10.27; level D (66 tpm, two-feet skip, rhythm bounce): 9.05; level E (84 tpm, two-feet skip, plain bounce): 11.02; level F (102 tpm, two-feet skip, plain bounce): 12.58; level G (120 tpm, two-feet skip, plain bounce): 11.91; level H (132 tpm, two-feet skip, plain bounce): 11.55. ANOVA and the SCHEFFE test revealed a significant statistical difference only between levels D and F (.05 level). Mean terminal heart rates ranged from 146 b/min for level D to 176 b/min for level F. Lactate response reached mean values of 51 mg% for level D and 110 mg% for level F. The results indicate that rope skipping can be classified as heavy to exhausting work.

16. Jette M, Thoden JS & Spence J (1976): The energy expenditure of a 5 km cross-country ski run. J.Sports Med.Phys.Fitness, 16, 134-137.

This study was designed to directly determine the net energy cost of skiing a typical 5 km run at competitive speed. Three members of the Canadian National Cross-Country Ski Team were employed as subjects. Pulmonary ventilations were collected with a KM respirometer and expired air was analyzed in situ. EKG recordings were monitored throughout the run. The net mean energy expenditure for the run was established at 20.9 cal/min or 0.296 Cal/kg/min. This would represent a caloric expenditure of 483 Cal for a 70 kg male completing the course in 23 min. 33 sec. In terms of VO2 per kg body weight it was determined that the skiers performed at a mean VO2 of 59.8 ml/kg/min or 90% of their treadmill induced max VO2 measured under laboratory conditions. The practical applications of this study are discussed.

17. Klissouras V (1968): Energy metabolism in swimming the dolphin stroke. Int.Z.angew. Physiol.einschl.Arbeitsphysiol. 25, 142-150.

The energy metabolism of subjects while they swam using the dolphin-butterfly stroke was analyzed. It was found that: 1. The oxygen consumption while swimming with the whole stroke, the arm-stroke or leg-kick, increased exponentially with an arithmetical increase in swimming velocity. 2. At competitive speeds swimming with only the leg-kick requires more energy than swimming at the same velocity with either the arm-stroke or the whole stroke. 3. A parabolic pattern is shown for the mechanical efficiency while swimming by use of each of the three methods. The mechanical efficiency increases as the velocity of swimming increases from 0 to an optimum velocity and then decreases as the velocity exceeds this value. 4. At competitive speeds swimming with only the leg-kick is less efficient than swimming with either the arm-stroke or the whole stroke. 5. At maximum speeds swimming with the whole stroke is slightly more efficient than swimming with the arm-stroke. The shortcomings of the "oxygen-dept" method for the measurement of oxygen consumption during submaximal exercise are discussed.

18. Knowlton RG, Ackerman KA & Kaminsky LA (1988): Physiological and performance comparisons of running flat and hill routes as applied to orienteering navigation. J.Sports Med.Phys.Fitness, 28, 189-193.

Twenty-six men ran under simulated orienteering conditions to determine performance and energy expenditure characteristics required of a flat route (FR) and two hill routes; one a gradual incline (GI) and one an abrupt incline (Al). The actual speed was greater on FR but slower when computed by the straight line distance as is done by orienteering convention. The energy requirement for FR was the higher, 23.8 kcal, and the least for Al, 17.5 kcal. Although the two hill courses were identical in length, there was a significant difference in energy expenditure between Gl, 18.9 kcal, and Al, 17.5 kcal. It was speculated that contrasts in the duration of positive and negative work accounted for the differences in energy expenditure between the two hill routes. The perception of exertion, RPE was nearly identical (10.6) for the three routes. Although the energy demands were similar, it was concluded that speed calculated by orienteering convention was the most reasonable criterion for route selection. This was supported by the examination of forty-seven experienced orienteers of maps representing the test routes of this study. Although Al proved the preferable choice, it is proposed that 1.8 units of flat distance to each unit of gradual climb is a reasonable criterion for route selection, at least for a 10 m hill. This refutes the 10:1 ratio suggested in the early orienteering literature.

19. Marion GA & Leger LA (1988): Energetics of indoor track cycling in trained competitors. Int.J.Sports Med. 9, 234-239.

Departement d'Education physique, Université de Montreal, Quebec, Canada. Steady-state track VO2 was estimated by means of the retroextrapolation method in seventeen competitive male cyclists at speeds ranging from 28 to 43 km.h-1. Peak VO2 was also determined using an ergocycle multistage test (80 rev.min-1). Results showed large VO2 variations at similar speeds on the track (SEE greater than 10% Y; n = 17). Third degree regressions were the most accurate to describe the evolution of VO2 with speed, while the units ml.kg-0.667.min-1 showed better correlations and lower dispersions than 1.min-1, ml.kg-1.min-1, and 1.min-1.m-2. When categorized according to the Quebec Cycling Federation ranking, (elites: n = 6; nonelites: n = 11), the elites tended to demonstrate to a lower mean VO2 for the range of velocities studied. The difference was, however, not statistically significant (P greater than 0.05). Interindividual variations were reduced by expressing VO2 and speed as relative percentages of maximal values in ten subjects: % MAP = 6.475 e exp [0.0274% MAS] where % MAP = track V02/laboratory peak VO2, and % MAS = speed/speed associated with peak VO2 on the track. No significant difference was observed between track and ergocycle peak VO2 (P greater than 0.05), indicating the validity of the 80 rev.min-1 protocol for laboratory evaluation of racing cyclists. The concept of cycling economy as a contributing factor to performance and applications of the % MAP-% MAS relationship are discussed.

20. McArdle WD, Glaser RM & Magel JR (1971): Metabolic and cardiorespiratory response during free swimming and treadmill walking. .J.Appl.Physiol 30, 733-738.

The VO2 and telemetered HR and ventilatory response during free swimming and walking were studied in five male trained college swimmers. The swimming and walking tests were of the discontinuous type in which the subject exercised for 4-min at increasing work levels up to maximum. During walking, work was regulated by increasing the elevation of the treadmill. In the swimming test, work was altered by increasing the stroke frequency by means of an electronic pacing device. VO2 was essentially linearly related to work intensity in the swimming and walking tests. However, the slope of the HR-V02 line was shifted to the right during free swimming. For any level of VO2 within the range measured, the HR during swimming averaged 9-13 beats/min lower than the HR walking. Maximum HR averaged 22 beats/min lower in the swimming test (P<0.01). At VO2 above 2.0 L/min breathing frequency was approximately the same in both forms of exercise with a tendency for it to be slightly higher during swimming. At submaximal work levels VE was quite similar in both forms of work. However, the maximum VE and breathing rate were significantly higher in walking than in swimming. During submaximal work oxygen extraction was generally higher in swimming throughout the entire range of work. The energy cost of swimming at various speeds is presented in relation to previously reported data.

21. McCole SD, Claney K, Conte J. Anderson R & Hagberg JM (1990): Energy expenditure during bicycling. .J.Appl.Physiol 68, 748-753.

Department of Exercise and Sport Science, College of Health and Human Performance, University of Florida, Gainesville 32611. This study was designed to measure the 02 uptake VO2 of cyclists while they rode outdoors at speeds from 32 to 40 km/in. Regression analyses of data from 92 trials using the same wheels, tires, and tire pressure with the cyclists riding in their preferred gear and in an aerodynamic position indicated the best equation (r = 0.84) to estimate VO2 in liters per minute VO2 = - 4.50 + 0.17 rider speed + 0.052 wind speed + 0.022 rider weight where rider and wind speed are expressed in kilometers per hour and rider weight in kilograms. Following another rider closely, i.e., drafting, at 32 km/in reduced VO2 by 18 +/11 %; the benefit of drafting a single rider at 37 and 40 km/in was greater (27 +/- 8%) than that at 32 km/in. Drafting one, two, or four riders in a line at 40 km/in resulted in the same reduction in VO2 (27 +/- 7%). Riding at 40 km/in at the back of a group of eight riders reduced VO2 by significantly more (39 +/- 6%) than drafting one, two, or four riders in a line; drafting a vehicle at 40 km/in resulted in the greatest decrease in VO2 (62 +/- 6%). VO2 was also 7 +/- 4% lower when the cyclists were riding an aerodynamic bicycle. An aerodynamic set of wheels with a reduced number of spokes and one set of disk wheels were the only wheels to reduce VO2 significantly while the cyclists were riding a conventional racing bicycle at 40 km/in. Thus drafting and using aerodynamically designed equipment can alter the energy expenditure of cyclists at speeds similar to those encountered at competitive events (32-40 km/h).

22. Myles WS (1979): The energy cost of an 80 km run. Br.J.Sports Med. 13, 12-14.

Data was collected from two men who attempted an 80 km run. Measurements of aerobic power VO2 max) and determinations of heart rate (HR) and submaximal oxygen consumption VO2 during treadmill running were carried out one week before the run. Throughout the 80 km run, HR was recorded by telemetry and used together with the laboratory data to estimate VO2 as a percentage of VO2 max. One subject completed the 80 km distance at 58% of VO2 max. the other subject, operating at 74% of VO2 max. was obliged to retired after 55 km. The data in this and other studies indicate that the high energy costs reported for the marathon (70-85% of VO2 max) cannot be sustained over the 80 km distance but that about 60% of VO2 max can be continued for seven hours and longer.

23. Nadel ER, Holmer I, Bergh U, Astrand PO & Stolwijk JA (1974): Energy exchanges of swimming man. .J.Appl.Physiol 36, 465-471.

Three male swimmers underwent 10-min resting and 20-min swimming (breaststroke) exposures in a swimming flume. Water temperatures in separate exposures were 18, 26 and 33 °C. At each water temperature the subjects rested and swam at water velocities of 0.50, 0.75 and 0.95 m.s^-1, which were designed to produce around 40, 70 and 100% of maximal aerobic power. Measurements were made of esophageal temperature (T_es), four skin temperatures, water temperature, heat flow from five local skin surfaces (Hatfield-Turner discs), and oxygen uptake (VO2). Calculations were made of mean area-weighted skin temperature (Ts) and heat flow, metabolic rate and heat storage. Internal body temperature changes after 20 min of swimming were related to water temperature, swimming intensity and body composition. VO2 was proportional to swimming speed during submaximal efforts in any swimming speed and became greater as the swimmer approached his maximal effort. VO2 was also greater in 18 °C than in 26 °C water at any submaximal swimming speed and likewise greater in 26°C than in 33°C water. Increased cost of swimming in cold water was largely attributed to shivering. The convective heat transfer coefficient was calculated from heat flow and skin and water temperature data and was found to be 230 W.m^-2.°C^-1 at rest in still water, 460 W.m^-2.°C^-1 at rest in moving water, and 580 W.m^-2.°C:⁰¹ while swimming, regardless of swimming speed. Core-to-skin conductances were primarily related to internal temperature, although there appeared to be a minor effect of T_s modifying this relation.

24. Niinimaa V, Dyon M & Shephard RJ (1978): Performance and efficiency of intercollegiate cross-country skiers. Med.Sci.Sport Exerc. 10, 91-93.

Ten male intercollegiate cross-country skiers were studied to identify factors influencing competitive performance and to estimate the efficiency of energy expenditure in skiing. The variables examined were maximum oxygen intake, as determined by both uphill treadmill running and by maximal level skiing, physical characteristics, strength and experience in cross-country skiing and racing. Multiple regression analysis showed that racing experience, cardiorespiratory fitness, and body fat percentage were significant factors in racing success. The net mechanical efficiency at this level of competition was estimated at 21.3%.

25. Reilly T & Thomas V (1979): Estimated daily energy expenditures of professional association footballers. Ergonomics, 22, 541-548.

The daily energy demands of 23 professional English League footballers were estimated. Indirect measurement was made of energy expended in training, match-play and non-occupational activity. Mean duration of training was 75 min day^-1, mean heart rate 132 beats min^-1. Match-play constituted the dominant source of occupational strain, mean heart rate being 157 beats min ^-1 in outfielders. Temporal commitment to work was 18.5 h week ^-1 during which mean work intensity could be described as moderate. Time spent inactive was 19.5 h day-1 and daily energy expenditure was estimated to be 14.442 MJ. It was concluded that physiological strain in this occupation was not excessive and no peculiar dietary requirements obtained.

26. Saibene F. Cortili G. Gavazzi P & Magistri P (1985): Energy sources in alpine skiing (giant slalom). Eur.J.Appl.Physiol 53, 312-316.

The energy cost of a giant slalom event was measured in eight skiers of national level. The lap lasted on average 82 s. VO2 was measured during the first, the second and the last third of the lap in different trials and also during recovery from a complete lap. Blood lactate was measured at the end of a lap. From the data obtained it was possible to calculate that: a) VO2 as measured during the lap, would correspond at steady state to 80% of the VO2max of the subjects; b) the total metabolic power delivered during the lap should be equal to about 72 ml 02.kg-1.min-1, corresponding to 120% of VO2max of the subjects. Considering the short duration of the trial and the power output delivered during maximal efforts on a bicycle ergometer, it appears that the giant slalom is not a very high energy demanding event.

27. Saibene F. Cortili G. Roi G & Colombini A (1989): The energy cost of level cross-country skiing and the effect of the friction of the ski. Eur. J.Appl.Physiol 58, 791-795.

Istituto Tecnologie Biomediche Avanzate, C.N.R., Milano, Italy. Oxygen consumption VO2 in ml.kg-1.min-1], blood lactate concentration ([La] in mM) and dynamic friction of the skis on snow [(F) in N] were measured in six athletes skiing on a level track at different speeds [(v) in m.min-1] and using different methods of propulsion. The VO2 increased with v and F. the latter depending mostly on snow temperature, as did [La]. The VO2 was very much affected by the skiing technique. Multiple regression equations gave the following results: with diagonal stride (DS), VO2 = -23.09 + 0.189 v + 0.62 N; with double pole (DP), VO2 = -30.95 + 0.192 v + 0.51 N; and with the new skating technique (S), VO2 = -32.63 + 0.171 + 0.68 N. In terms of VO2 DS is the most expensive technique, while S is the least expensive; however, as F increases, S. at the highest speed, tends to cost as much as DP. At speeds from 18 to 22 km.h-1, the speeds measured in the competitions, the F for DS and DP can represent from 10% to 50% of the energy expenditure, with F ranging from 10 to 60 N; with S this range increases to 20%-70%. This seems to depend on the interface between the skis and the snow and on the different ways the poles are used.

28. Schmidt RJ, Housh TJ & Hughes RA (1985): Metabolic response to kendo. J.Sports Med. Phys. Fitness, 25, 202-206.

To determine the physiological intensity and aerobic cost of playing kendo, the heart rate responses of eight subjects (mean age 28 +- 4.8 years) were monitored continuously via radiotelemetry during a 5-minute kendo bout (jigeiko). In addition, aerobic capacity (VO2max) and heart rate values were determined during a treadmill test employing continuous incremental protocol and compared to values obtained during kendo jigeiko. The mean playing VO2 was 45 +7.6 ml/kg.min-1 representing 89% of VO2max and 111% of anaerobic threshold (AT). The mean metabolic intensity was 14.6 +- 0.7 METS. The caloric equivalent for the mean playing R value (0.99 +- 0.09) was 5.04 kcal/liter 02. The mean caloric expenditure during competition was 15.64 +- 3.06 kcal/min. Spearman Rank Order correlations revealed that of the physiological variables measured, only VO2max was significantly (p<0.05, r₃=-0.79) associated with kendo playing ability. These findings indicate that kendo jigeiko of 5 minuses' duration is of sufficient intensity and duration to stimulate cardiorespiratory fitness. The use of the arms, grip on the shinai, and the explosive nature of the techniques may serve as mechanisms for the elevation of the heartrate. Furthermore, oxidative metabolic factors (particularly VO2max contribute substantially in ability between competitors.

29. Seliger V (1968): Energy metabolism in selected physical exercises. Int.Z.angew.Physiol. einschl.Arbeitsphysiol. 25, 104-120.

The energy costs of 15 physical activities were examined in 275 subjects under training conditions of the particular activity. The sample contains usually 15 medium athletically developed persons at minimum. The energy metabolism was followed by indirect calorimetrical method, the heart rate was registered throughout the experimental telemetrically. The activities were divided into three groups, according to the time of duration. The results showed that the energy expenditure ranges were in A-group (duration 5 min and more) 0.08-0.26 kcal/min/kg, in B-group (1-3 min) Q.11-0.45 kcal/min/kg, and in C-group (1-30 see) 0.68-1.75 kcal per min/kg. The observed values of heart rate, pulmonary ventilation, and oxygen uptake are discussed. No correlation between the energy expenditure and the intensity of the motional activity, according to pedagogues' observation was found. The relationship to physiological function was with respect to motional activity on 1-5% significance level, especially in sports from groups A and B. A graph was constructed of the relationship of the intensity of metabolism, against duration of the activity. Three fields limited by parallel lines enables the judgement of the real metabolic rate during the sports' activity of examined persons to functional development of his organismus.

30. Seliger V, Ejem M, Pauer M & Safarik V (1973): Energy metabolism in tennis. Int.Z.angew.Physiol. einschl.Arbeitsphysiol. 31, 333-340.

Physiological responses of a group of 16 tennis players have been investigated under the almost natural conditions of a 10 min long training match. Collecting the expired air into Douglas bags, transmitting heart rate all the time of experiment wirelessly and analysing every player's activity, yielded the following main results: The average intensity of metabolism was 919.5% BMR, that is 0.14 kcal per min and kg of body weight. The oxygen uptake have been found 27.3 ml O2/min.kg, while the mean heart rate during the match was counted as 143 beats/mint It was found, too, that players ran totally 240 m, executed in average 62 strokes and used 41.1% of the total time for real play. With regard to our results tennis can be grouped together with bicycleball and American handball, while basketball, European handball, soccer and ice-hockey on one hand, and volleyball with table-tennis on the other hand, differ significantly. There was also found to be significant difference between caloric output in recreational and competitive type of tennis game. This investigation then can support the view that, in the main, tennis means the submaximal load for players.

31. Seliger V, Kostka V, Grusova D, Kovac J. Machovcova J. Pauer M, Pribylova A & Urbankova R (1972): Energy expenditure and physical fitness of ice-hockey players. Int.Z.angew.Physiol. einschl.Arbeitsphysiol. 30, 283-291.

We examined the energy expenditure in ice-hockey players under conditions of a model training match. The results were obtained in a group of 13 players of the national representative team (age 24.4 years), and in 1 goaler. In the players we also followed the physical fitness by means of a loading experiment on bicycle ergometer in the middle of the racing season, and before the opening of the World Championship 1971. The principal results are as follows: the energy expenditure during the play is 0.48 kcal/min.kg (3137%BMR), the oxygen debt 6.3 I. The anaerobic part of the metabolism is approximately two thirds of the total energy expenditure .The average heart rate during the activity on ice was 152 beats per minute, the pulmonary ventilation 92 I, the oxygen uptake 32 ml/min.kg. During one turn (1.17 min) the players covered the distance 285 m. The comparison of maximum values of the indices obtained by ergometrical examination in two examinations did not show any substantial differences. We can assume that the decrease observed in several indices may have been caused by a low motivation at loading up to the maximum (the lactic acid, pulmonary ventilation, oxygen uptake). Other findings (the fat percentage increment) can be explained by less intensive training, unbalance between performance and nutrition. A relative independent index is the W 170 which has shown the unchanged level of cardiorespiratory functions. From the results various conclusions can be drawn for the work of trainers. The ice-hockey proves to be an activity with mostly sub-maximal metabolic rate, where appears a great part of anaerobic metabolism simultaneously with high requirements for the aerobic metabolism. For the training practice the requirements follow to intensify the interval training, to increase the play intensity in the training, to use the necessary number of play exercise requiring the typical anaerobic power, and load the players, in the preparatory period, more often by endurance activities for the aerobic endurance be developed.

32. Smith HK, Montpetit RR & Perrault H (1988): The aerobic demand of backstroke swimming, and its relation to body size, stroke technique, and performance. Eur.J.Appl.Physiol 58, 182188.

Department of Physical Education, McGill University, Montreal, P.Q., Canada. Few studies have examined the aerobic demand of backstroke swimming, and its relation to body morphology, technique, or performance. The aims of this study were thus to: i) describe the aerobic demand of backstroke swimming in proficient swimmers at high velocities; ii) assess the effects of body size and stroke technique on submaximal and maximal 02 costs, and; iii) test for a relationship between submaximal 02 costs and maximal performance. Sixteen male competitive swimmers were tested during backstroke swimming at velocities from 1.0 to 1.4 m.s-1. Results showed that VO2 increased linearly with velocity (m.s-1) following the equation VO2 = 6.28v - 3.81 (r = 0.77, SEE/Y = 14.9%). VO2 was also related to the subjects' body mass, height, and armspan. Longer distances per stroke were associated with lower 02 costs, and better maximal performances. A significant relation was found between VO2 at 1.1 m.s-1, adjusted for body mass, and 400 m performance (r = -0.78). Submaximal VO2 was also related to reported times for 100 m and 200 m races. Multiple correlation analyses indicated that VO2 at 1.1 m.s-1 and VO2max accounted for up to 78% of the variance in maximal performances. These results suggest that the assessment of submaximal and maximal VO2 during backstroke swimming may be of value in the training and testing programs of competitive swimmers.

33. Toussaint HE, Beelen A, Rodenburg A, Sargeant AJ, de Groot G. Hollander AP & van Ingen Schenau GJ (1988): Propelling efficiency of front-crawl swimming. .J.Appl.Physiol 65, 25062512.

Department of Exercise Physiology and Health, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands. In this study the propelling efficiency (ep) of front-crawl swimming, by use of the arms only, was calculated in four subjects. This is the ratio of the power used to overcome drag (Pd) to the total mechanical power (Po) produced including power wasted in changing the kinetic energy of masses of water (Pk). By the use of an extended version of the system to measure active drag (MAD system), Pd was measured directly. Simultaneous measurement of 02 uptake (VO2) enabled the establishment of the relationship between the rate of the energy expenditure (PVO2) and Po (since when swimming on the MAD system Po = Pd). These individual relationships describing the mechanical efficiency (8-12%) were then used to estimate Po in free swimming from measurements of VO2. Because Pd was directly measured at each velocity studied by use of the MAD system, ep could be calculated according to the equation ep = Pd/(Pd + Pk) = Pd/Po. For the four top class swimmers studied, ep was found to range from 46 to 77%. Total efficiency, defined as the product of mechanical and propelling efficiency, ranged from 5 to 8%.

34. van Ingen Schenau GJ, de Groot G & Hollander AP (1983): Some technical, physiological and anthropometrical aspects of speed skating. Eur.J.Appl.Physiol 50, 343-354.

Five elite speed skaters and fourteen well trained skaters of a lower performance level performed three maximal tests: a 3,000 m race from which the skating position and the stroke frequency were derived, an oxygen consumption test both during skating and during a bicycle ergometer test. From all subjects anthropometric measures were taken. The elite group showed a VO2 during cycling of 64.4 +/- 3.5 ml.kg-1.min-1 and 59.4 +/- 3.7 ml.kg-1.min-1 during skating. The elite skaters showed: a shorter upper leg length with respect to total leg length, higher aerobic power during cycling, higher stroke frequency, smaller pre-extension knee angle coupled to higher work per stroke, higher "efficiency" during skating and higher external power during skating and during cycling when compared with the group of lower performance level. It is concluded that an important pre-requisite for speed skating appears to be the possibility to skate at a small pre-extension knee angle without an excessive claim to anaerobic metabolism.

35. Veicsteinas A, Ferretti G. Margonato V, Rosa G & Tagliabue D (1984): Energy cost of and energy sources for alpine skiing in top athletes. .J.Appl.Physiol 56, 1187-1190.

O2 uptake VO2 during exercise and at 2 min of the recovery along with blood lactate concentration 5 min after exercise were measured in an all-out special slalom (SS) and giant slalom (GS) performed by eight top male athletes and five controls in a field study. Heart rate (HR) was continuously monitored before, during, and after each task. On the basis of an energy equivalent of 3.15 ml O2.kg body wt-1 for 1 mmol.1-1 lactate accumulation and the assumption that the amount of 02 consumed in recovery is used to reconstitute approximately phosphates used during the exercise, the total energy cost (delta VO2 tot) could be calculated and subdivided into aerobic, lactic, and alactic fractions. In top athletes, delta VO2 tot was equal during SS and GS [7.28 +/- 1.14 (SD) and 7.47 +/- 0.89 liters for about 55- and 70-s performances, respectively]. When referred to time, the 02 expenditure rate was 2 and 1.6 times VO2max in SS and GS, respectively. In SS and GS, the energy sources were about 40% aerobic, 20% alactic, and 40% lactic metabolism. In control skiers, delta VO2 tot of GS was 6.12 +/- 1.45 liters for 77 s, amounting to about 1.3 VO2max with the contribution of the different energy sources being roughly the same as in top skiers. HR reached maximal values in 30-40 s in all subjects for all conditions.

36. Wilson GD & Sklenka MP (1983): A system for measuring energy cost during highly dynamic activities. J.Sports Med. 2:3, 155-158.

It has been suggested that the widely used portable respirometers (eg Max Planck) might be restrictive in some energy cost measurement situations. Therefore an alternative portable system made up of easily obtainable and inexpensive pieces was designed and compared to the Max Planck during a fastpaced game (raquetball). After play with each system, sixteen subjects were asked to complete a questionnaire relative to how the system affected their movement, their skill performance, and their comfort during play. The newly designed system fared statistically significantly better with respect to both movement and comfort. Thus, it appears that the modified portable system is to be preferred in racquet sport energy cost studies where the movement and comfort limitations of the more commonly used respirometers become significant and restrictive.

37. Zhuo D, Shephard RJ, Plyley MJ & Davis GM (1984): Cardiorespiratory and metabolic responses during Tai Chi Chuan exercise. Can.J.Appl.Sport Sci. 9, 7-10.

Tai Chi Chuan is a form of traditional Chinese exercise which has been widely practiced in China for preventive and therapeutic purposes. The present study was designed to determine the physiological demands of this exercise modality. Eleven healthy males, aged 28.4 years, were studied for oxygen cost and related metabolic variables, heart rate and blood pressure during the performance of the Long-Form Tai Chi Chuan of Yang's style. Data was collected by an automated respiratory gas analyzer (Jeger Ergooxyscreen) and ECG telemetry during a 1725 minute performance session (X = 22 minutes). The average energy cost for the Long-Form Tai Chi Chuan was 4.1 Mets, corresponding to a mean VO2 value of 1.03 I.min-1 or 14.5 ml.kg-1.min-1. The mean peak heart rate during the exercises was 134 beats per minute. These values suggest that the Long-Form Tai Chi Chuan may be classed as moderate exercise, and its intensity does not exceed 50% of the individual's maximum oxygen intake.

4.3.2 Women

1. Abernethy P & Batman P (1994): Oxygen consumption, heart rate and oxygen pulse associated with selected exercise-to-muscle class elements. Br.J.Sports Med. 28, 43-46.

Department of Human Movement Studies, University of Queensland, Brisbane, Australia. The purpose of the investigation was to determine the relative oxygen consumption VO2 heart rate and oxygen pulse associated with the constituent elements of an exercise-to-music class. Six women exercise-to-music leaders with a mean(s.d.) age, weight and height of 33.2(5.2) years, 51.0(2.8) kg and 157.9(5.6) cm respectively, completed five distinct exercise-to-music movement elements. The movement elements were of a locomoter (circuit, jump and low impact) and callisthenic (prone and side/supine) nature. The movement elements were distinguishable from one another in terms of their movement patterns, posture and tempo. Relative VO2 values were greatest for the circuit element (40.6 ml kg-1 min-1) and least for the side/supine element (20.0 ml kg-1 min-1). The differences in VO2 between the locomotor and callisthenic elements were significant (circuit approximately jump approximately low impact > prone approximately side/supine). However, effect size data suggested that the differences between the low impact and jump elements and the prone and side/supine elements were of practical significance (circuit approximately jump > low impact > prone > side/supine). With a single exception similar parametric statistics and effect size trends were identified for absolute heart rate. Specifically, the heart rate associated with the low impact element was not significantly greater than the prone element. The oxygen pulse associated with the locomotor elements was significantly greater than the callisthenic elements (circuit approximately jump approximately low impact > prone > side/supine). This suggested that heart rate may be an inappropriate index for making comparisons between exercise-to-music elements. Reasons for differences in oxygen uptake values between movement elements are discussed.

2. Chatard JC, Lavoie JM & Lacour JR (1991): Energy cost of front-crawl swimming in women. Eur.J.Appl.Physiol 63, 12-16.

Laboratoire de Physiologie, Faculté de Medecine de Saint-Etienne, C. H. R. U . de Saint-Etienne, France. The purpose of this study was to examine the relationship between the energy cost of swimming per unit distance (Cs) at different velocities (v) and performance level, body size and swimming technique in women. A total of 58 females swimmers were studied. Three performance levels (A, B. C) were determined, ranging from the slower (A) to the faster (B. C). At level C and at 1.1 m.s-1, Cs,1.1 was reduced by 7% when directly compared to level B. The Cs,1.1 was reduced by 10% when calculated per unit of height (h) and by 37% when calculated per unit of h and hydrostatic lift (HL). For the whole group of swimmers, the equation regression was Cs,1.1 = 0.27 h-2.38 HL - 7.5 (r = 0.53, P less than 0.01). To evaluate the specific influence of arm length two groups of long- and short-armed swimmers were selected among swimmers of similar h and performance. The Cs was significantly higher (P less than 0.05) by 12%, SD 2.2%, for short-armed than for long-armed swimmers. To evaluate the influence of different types of swimming technique, two other groups of similar performance and anthropometric characteristics were selected. The Cs was significantly higher (P less than 0.05) by 12%, SD 4.5% for swimmers using for preference their legs rather than their arms. The Cs of the sprinters was 15.7%, SD 2% higher than that of the long-distance swimmers. For all groups, Cs increased with v on average by 8% to 11% every 0.1 m.s-1. These findings showed that Cs variations of these women were close to those previously demonstrated for men. The Cs depends on performance level, body size, buoyancy, swimming technique and v.

3. Figura F. Cama G & Guidetti L (1993): Heart rate, alveolar gases and blood lactate during synchronized swimming. J.Sports Sci. 11, 103-107.

Istituto di Fisiologia Umana, Universita La Sapienza, Roma, Italy. Heart rate, alveolar gas partial pressures and blood lactate (BLa) concentration were measured during synchronized swimming in six subjects. During upside-down breath-holding lasting 50 s, heart rate fell progressively from 98 +/- 14 to 70 +/- 7 beats min-1 (mean +/- S.D.). While breath-holding during the compulsory figures, the subjects' heart rate increased to 142 +/- 5 beats min-1 and then fell to 72 +/- 10 beats min-1. At the end of breath-holding, alveolar oxygen pressure had fallen significantly (60 mmHg), whereas alveolar carbon dioxide pressure showed only minor changes (48 mmHg). The increase in BLa concentration due to the execution of compulsory figures was approximately 1 mM; in the free routines, BLa concentration increased by 3.4 +/- 0.5 mM. The net energy cost of completing a compulsory figures lasting 45 s was 34.6 kJ.

4. Nelson DJ, Pels AK, Geenen DL & White TP (1988): Cardiac frequency and caloric cost of aerobic dancing in young women. Res.Q.Exerc.Sport, 59, 229-233.

Our primary purpose was to characterize cardiac frequency during aerobic dancing. A continuous ECG tape recording was obtained on 13 women (21+- .5 yrs; X+- SEM) during aerobic dance classes. The tape was subsequently analyzed by microcomputer for min-by-min heart rate (HR) characteristics. During the main dancing phase of 35 min. the total elapsed time the subjects' HR was greater than or equal to HR reserve thresholds of 60%, 70%, and 80% was 23.9 +- 2.29 min. 17.2 +- 2.75 min. and 9.5 +- 2.24 min. respectively. The longest continuous time that HRs exceeded the minimal threshold of 60% was 17.8 +-2.64 mini this value decreased at the higher threshold of 70% and 80% to 12.4 +- 2.28 and 6.8 +- 1.80 min. respectively. Aerobic dancing can sustain an elevated cardiac frequency, although not all participants demonstrated this response. The caloric cost of aerobic dancing was estimated from HR during dance and the subjects' HR-oxygen consumption relationship determined in the laboratory. The caloric cost during the main dancing phase of the class was estimated to be 8 +- 1.3 kcal/min.

5. Noble L (1975): Heart rate and predicted VO2 during women's competitive gymnastic routines. J.Sports Med. 15, 151-157.

This study attempted to determine the energy expenditure of three highly skilled women gymnasts while participating in competitive optional and compulsory routines on the uneven parallel bars, balance beam, and floor exercise. Activity telemetered heart rates were used to predict VO2 using individual heart rate-VO2 regression lines obtained in the laboratory. The subjects were aged 16, 18 and 22 years. Two subjects were finalists in the 1972 U.S. Junior Olympic competition. Mean maximum VO2 and heart rates of the three subjects were 61.77 ml/kg/min and 184 bpm, respectively. Mean heart rates during performance of the routines ranged from 132 to 176 b/min. Predicted VO2 during performance of the routines ranged from 28.73 to 55.64 ml/kg/mint Optional routines were more strenuous than compulsory routines. Floor exercise routines were most strenuous and routines on the beam were least strenuous.

6. Noble RM & Howley ET (1979): The energy requirement of selected tap dance routines. Res.Q. 50, 438-442.

The primary purpose of this study was to measure the oxygen requirement of two tap dance routines. A secondary purpose was to determine if differences existed between beginning and intermediate tap dance students in the energy requirements for these dance routines. Fifteen female subjects, ranging in age from 17 to 26 years, participated in the study. Eight of the subjects were classified as beginners and seven as intermediates in their ability to tap dance. Each subject performed two tap dance routines, soft shoe and slow buck, to a medley of recorded music of 112 beats per minute (bpm). Expired gas samples were obtained from 2.5 to 3.5 and 3.5 to 4.5 minutes into each routine. There was a short rest period between routines. The mean and standard deviation of oxygen uptake was 16.6 ± 3.1 ml/kg x min for the soft shoe routine and 16.8 + 3.4 ml/kg x min for the buck routine. There was no significant difference between these two routines or between the beginners and intermediates for the energy requirements of either dance routine (p>.05). The above values place tap dancing at 112 bpm at the same intensity as the waltz, foxtrot, rumba, Petronella, and Eightsome Reel.

7. Scharff Olson M, Williford HN, Blessing DL & Greathouse R (1991): The cardiovascular and metabolic effects of bench stepping exercise in females. Med.Sci.Sport Exerc. 23, 1311-1317.

Human Performance Laboratory, Auburn University, Montgomery, AL 36117. The purpose of this investigation was to measure cardiovascular and metabolic responses to 20 min continuous bouts of "choreographed" bench stepping exercise in healthy females. Four frequently used bench heights were employed in E' cross-over design: 15.2 cm (6 inches, B-6), 20.3 cm (8 inches, B-8), 25.4 cm (10 inches, B-10), and 30.5 cm (12 inches, B-12). Oxygen uptake (VO2) responses were significantly more pronounced in direct relationship to the bench height: B-12 >

B-10 > > B-8 > B-6 (P< 0.05). Mean responses for VO2 ranged from 28.4 ml.kg-1.min-1 for B-6 to 37.3 ml.kg-1.min-1 for B-12. Interestingly, no difference was revealed for heart rate and the respiratory exchange ratio between B-12 and B-10 despite a higher VO2 for B-12 (B-12, B-10 > B-8 > B-6, P < 0.05). The incorporation of 0.91 kg (2 lb) hand weights with exercise on the 20.3 cm bench elicited a modest but statistically significant increase in VO2 compared with no hand weights. No significant increase in VO2 was revealed for conditions that employed 0.45 kg (1 lb) hand weights. The results demonstrate that aerobic bench stepping is an exercise modality that provides sufficient cardiorespiratory demand for enhancing aerobic fitness and promoting weight loss in females.

8. Skubic V & Hodgkins J (1966): Energy expenditure of women participants in selected individual sports. .J.Appl.Physiol 21,133-137.

Energy expenditure was determined for two women subjects while exercising on a treadmill. Ventilation, oxygen consumption, and caloric determinations were made when the heart rate reached levels during exercise. The subjects also participated in the playing of five individual type sports and their heart rates were telemetered throughout the activity. Resting and recovery rates were also obtained each day of testing. Regression coefficients for each subject were found showing the relationship between heart rate and ventilation, heart rate and kilocalories, and heart rate and oxygen consumption for work on the treadmill. From these data, estimates were made for the energy cost of game participation as calculated from the known heart rates. The various calculations indicated that badminton and tennis are significantly more strenuous than golf, bowling, and archery, and that golf and archery are more strenuous than bowling. According to available classifications on energy cost, badminton and tennis were rated as moderate activities and golf, bowling, and archery were rated as mild activities.

9. Williford HN, Blessing DL, Olson MS & Smith FH (1989): Is low-impact aerobic dance an effective cardiovascular workout? Physician Sportsmed. 16, 95-109.

Ten women performed four different aerobic dance routines in a randomized crossover study to evaluate energy expenditure. The routines consisted of the following combinations: low intensity, low impact; high intensity, low impact; low intensity high impact; and high intensity and high impact. The women warmed up for five minutes, then did a 20-minute routine. Metabolic measures were monitored by means of open circuit spirometry and heart rates measured by ECG. Statistical analyses showed that for both high and low intensities, the high-impact routines. required a significantly greater energy expenditure, regardless of heart rate. Thus for low-impact dance to meet the minimum guidelines for exercise suggested by the American College of Sports Medicine, it should be performed at high intensity.

4.3.3 Men & women

1. Adams WC (1967): Influence of age, sex, and body weight on the energy expenditure of bicycle riding. .J.Appl.Physiol 22, 539 545

Energy expenditure observations were made on 60 normal adult men and women, ranging in age from 20 to 52.2 years, while riding a narrow-tire bicycle at a previously determined average speed. Analysis of variance indicated that age had no effect on gross energy expenditure and that, when the latter was divided total body weight, there was no significant difference between men and women. The results of multiple regression analysis confirmed the dominant effect of total body weight, in that neither the addition of age, height, body surface area, lean body weight, fat body weight, or tricep skinfold contributed significantly to the prediction of energy expenditure for the ride.

2. Bergh U (1987): The influence of body mass in cross-country skiing. Med.Sci.Sport Exerc. 19, 324-331.

National Defense Research Institute, Environmental Stress and Human Performance, Stockholm, Sweden. The influence of body weight on the performance in cross-country skiing has been studied by: dimensional analysis of the ratio (R) between the factors of importance to power production VO2max acceleration of gravity) and the braking powers, e.g., friction and air resistance; measuring the energy cost of level skiing (N = 6); comparing male world class skiers (N = 5) with less successful ones (N = 34) and female winners of the National Championships (N = 9) with non-winners (N = 9) in regard to the relationship between body weight and VO2max The dimensional analysis revealed that R was less than unity for rather steep uphills. For level, downhill, and less steep uphill skiing, R was greater than unity. Thus, skiers who are light will be favored in steep uphill slopes, whereas heavier skiers have advantages in the other parts of the track. Energy cost per kilogram for level skiing was inversely related to the transported mass. Per unit of distance, this cost was positively related to velocity. The world class skiers displayed significantly greater VO2max than the less successful ones, regardless of the unit used. The lowest standard deviation among the world class skiers was attained when expressing VO2max as ml X min-1 X kg-2/3. The present results indicate that R will be quite close to unity and therefore the performance capability would theoretically be independent of body mass. Furthermore, VO2max is preferably expressed as ml X min-1 X kg-2/3 for cross-country skiers.

3. Blanksby BA & Reidy PW (1988): Heart rate and estimated energy expenditure during ballroom dancing. Br.J.Sports Med. 22, 57-60.

Department of Human Movement and Recreation Studies, University of Western Australia, Nedlands. Ten competitive ballroom dance couples performed simulated competitive sequences of Modern and Latin American dance. Heart rate was telemetered during the dance sequences and related to direct measures of oxygen uptake and heart rate obtained while walking on a treadmill. Linear regression was employed to estimate gross and net energy expenditures of the dance sequences. A multivariate analysis of variance with repeated measures on the dance factor was applied to the data to test for interaction and main effects on the sex and dance factors. Overall mean heart rate values for the Modern dance sequence were 170 beats.min-1 and 173 beats.min1 for males and females respectively. During the Latin American sequence mean overall heart rate for males was 168 beats.min-1 and 177 beats.min1 for females. Predicted mean gross values of oxygen consumption for the males were 42.8 +/-5.7 ml.kg-1 min-1 and 42.8 +/- 6.9 ml.kg-1 min-1 for the Modern and Latin American sequences respectively. Corresponding gross estimates of oxygen consumption for the females were 34.7 +/- 3.8 ml.kg-1 min-1 and 36.1 +/- 4.1 ml.kg-1 min-1. Males were estimated to expend 54.1 +/-8.1 kJ.min-1 of energy during the Modern sequence and 54.0 +/-9.6 kJ.min-1 during the Latin American sequence, while predicted energy expenditure for females was 34.7 +/- 3.8 kJ.min-1 and 36.1 +/- 4.1 kJ.min-1 for Modern and Latin American dance respectively. The results suggested that both males and females were dancing at greater than 80% of their maximum oxygen consumption. A significant difference between males and females was observed for predicted gross and net values of oxygen consumption (in L.min-1 and ml.kg-1 min-1).

4. Bransford DR & Howley ET (1977): Oxygen cost of running in trained and untrained men and women. Med.Sci.Sport Exerc. 9, 41-44.

The purpose of this study was to compare the oxygen cost of running as it relates to speed of running among the following four groups: trained male distance runners, trained female distance runners, untrained but active men and women. Each subject was given a series of treadmill tests during which Vo2 was measured at submaximal work loads. The linear regression equation was utilized to compute the relationship between Vo2 and running speed for each groups. The results indicated that the rate of increase in Vo2 for a given increase in running speed could be represented as a straight line and was the same for all groups (P greater than .05). The trained male runners had a significantly lower Vo2 (P less than .05) than those of the other three groups at any measured speed. The trained females and untrained males had significantly lower Vo2s than the untrained females (P less than .05) at any of the given range of speeds. No significant differences were observed between the untrained mean and trained women (P greater than .05). It was concluded that there were differences in the oxygen cost of running not only between the trained and untrained groups but also between males and females.

5. Brehm BA & Gutin B (1986): Recovery energy expenditure for steady state exercise in runners and nonexercisers. Med.Sci.Sport Exerc. 18, 205-210.

This study examined the effects of intensity, mode of exercise, and aerobic fitness on the energy expended during recovery (recovery oxygen consumption, or rec VO2 following steady state exercise. Eight runners (4 mares, 4 females; 22-32 yr) walked at 3.2 and 6.4 km X h-1 and ran at 8.1 and 11.3 km X h-1 (18, 33, 50, and 68% peak VO2 All subjects completed 3.2 km of walking or running each session. Eight sedentary adults (4 male, 4 female; 21-33 yr) completed the 6.4 km X h-1 test. For the runners, net rec VO2 for 3.2, 6.4, 8.1 and 11.3 km X h-1 exercise was (X +/-SE) 12.52 +/- 3.00, 29.53 +/- 5.41, 28.64 +/- 2.91, and 44.27 +/-5.32 ml X kg-1, respectively, for the recovery period (18-48 min). Differences among group means were significant (P less than 0.05), except between 6.4 and 8.1 km X h-1 walking (29.53 +/-5.41 and 35.09 +/- 9.39 ml X kg-1). Statements attributing substantial energy expenditure to the recovery period may be misleading to people exercising at levels similar to those described in this study, since the recovery energy expenditure only amounted to approximately 13-71 kJ (3-17 kcal).

6. Bunc V & Heller J (1989): Energy cost of running in similarly trained men and women. Eur.J.Appl.Physiol 59, 178-183.

Physical Culture Research Institute, Charles University, Prague 1, Czechoslovakia. The energy demand of running on a treadmill was studied in different groups of trained athletes of both sexes. We have not found any significant differences in the net energy cost (C) during running (expressed in J.kg-1.m-1) between similarly trained groups of men and women. For men and women respectively in adult middle distance runners C = 3.57 +/- 0.15 and 3.65 +/-0.20, in adult long-distance runners C = 3.63 +/- 0.18 and 3.70 +/- 0.21, in adult canoeists C = 3.82 +/- 0.34 and 3.80 +/- 0.24, in young middle-distance runners C = 3.84 +/- 0.18 and 3.78 +/-0.26 and in young long-distance runners C = 3.85 +/- 0.12 and 3.80 +/- 0.24. This similarity may be explained by the similar training states of both sexes, resulting from the intense training which did not differ in its relative intensity and frequency between the groups of men and women. A negative relationship was found between the energy cost of running and maximal oxygen uptake (VO2max) expressed relative to body weight (for men r = -0.471, p less than 0.001; for women r = -0.589, p less than 0.001). In contrast, no significant relationship was found in either sex between the energy cost of running and VO2max. We conclude therefore that differences in sports performance between similarly trained men and women are related to differences in VO2max.kg-1. The evaluation of C as an additional characteristic during laboratory tests may help us to ascertain, along with other parameters, not only the effectiveness of the training procedure, but also to evaluate the technique performed.

7. Burke EJ & Keenan TJ (1984): Energy cost, heart rate, and perceived exertion during the elementary backstroke. Physician Sportsmed. 12, 75-80.

The purpose of this study was to determine the energy cost of the elementary backstroke and to see if heart rate and perceived exertion are useful for monitoring exercise intensity. Five healthy men and five healthy women swam the elementary backstroke at four different intensities, and velocity, VO2 heart rate, and perceived exertion were monitored. Each dependent variable significantly increased with increasing intensity. The only sex difference was a higher VO2 in men for each work intensity. Average energy cost ranged from 0.097 kcal.kg^-1.min^-1 at 1.1 to 1.4 km.hr^-1 to 0.17 kcal.kg^-1.min^-1 at 1.8 to 2.0 km.hr^-1 (SEM + - 0.01). It was concluded that the elementary backstroke is suitable for a fitness program.

8. Capelli C, Zamparo P. Cigalotto A, Francescato MP, Soule RG, Termin B. Pendergast DR & di Prampero PE (1995): Bioenergetics and biomechanics of front crawl swimming. .J.Appl.Physiol 78, 674-679.

Dipartimento di Scienze e Tecnologie Biomediche, Universita di Udine, Italy. "Underwater torque" (T') is one of the main factors determining the energy cost of front crawl swimming per unit distance (Cs). In turn, T' is defined as the product of the force with which the swimmer's feet tend to sink times the distance between the feet and the center of volume of the lungs. The dependency of Cs on T' was further investigated by determining Cs in a group of 10 recreational swimmers (G1: 4 women and 6 men) and in a group of 8 male elite swimmers (G2) after T' was experimentally modified. This was achieved by securing around the swimmers' waist a plastic tube filled, on different occasions, with air, water, or 1 or 2 kg of lead. Thus, T' was either decreased, unchanged, or increased compared with the natural condition (tube filled with water). Cs was determined, for each T' configuration, at 0.7 m/s for G1 and at 1.0 and 1.2 m/s for G2. For T' equal to the natural value, Cs (in kJ.m-1.m body surface area-2) was 0.36 +/-0.09 and 0.53 +/0.13 for G1 in women and men, respectively, and 0.45 +/- 0.05 and 0.53 +/- 0.06 for G2 at 1.0 and 1.2 m/s, respectively. In a given subject at a given speed, Cs and T' were linearly correlated. To compare different subjects and different speeds, the single values of Cs and T' were normalized by dividing them by the corresponding individual averages. These were calculated from all single values (of Cs or T') obtained from that subject at that speed. The normalized Cs was found to be a linear function of the normalized T' (r=0.84, P<0.001; n-86) regardless of sex, speed, or swimming skill. We concluded that, in the speed range of 0.7-1.23 m/s, T' is indeed the main determinant of Cs regardless of sex or swimming skill.

9. Cohen JL, Segal KR, Witriol I & McArdle WD (1982): Cardiorespiratory responses to ballet exercise and the VO2max of elite ballet dancers. Med.Sci.Sport Exerc. 14, 212-217.

Physiologic responses to ballet exercise and VO2max during treadmill running were studied in elite professional ballet dancers (7 men, 8 women; age 20-30 yr) from the American Ballet Theatre. Ten dancers were studied during standard 1-h ballet classes consisting of 28 min of barre and 32 min of center floor exercise. Eight dancers performed maximal treadmill running tests yielding VO2max values (ml . min-1 . kg-1) of 48.2 (range 43.8-51.9) for men and 43.7 (range 40.9-50.1) for women. Mean VO2 (ml . min-1 . kg-1) during barre exercise was 18.5 (38% VO2max) for men and 16.5 (38% VO2max) for women; during center floor exercise 26.3 (55% VO2max) for men and 20.1 (46% VO2max) for women, with a peak of 77% VO2max for a male dancer. Mean caloric output values (kcal . kg-1 . min-1) during barre exercise were 0.09 and 0.08 for men and women, respectively, and during center floor exercise 0.13 for men and 0.10 for women, with a peak of 0.18 for one male dancer. Estimated net caloric outputs for the entire ballet class averaged 200 kcal . h-1 for women and 300 kcal . h-1 for men. During barre exercise, HR was below the training sensitive zone (70% HR max) for significant periods of time. Peak HR (beats . min-1) was relatively high during allegro center floor exercise, averaging 178 (92% HR max) and 158 (85% HR max) for men and women, respectively. However, these were maintained for only brief durations similar to sprint or burst activities. We conclude that these physiologic data obtained during ballet class represent only a relatively modest stimulus for augmenting aerobic (VO2max). In conjunction with the strong isometric component in ballet exercise, along with the sprint or burst component of ballet exercise, these factors would produce in elite ballet dancers VO2max values in the range of non-endurance athletes.

10. Holmer I (1972): Oxygen uptake during swimming in man. .J.Appl.Physiol 33, 502-509.

It is possible to set the water flow rate with great accuracy in a recently constructed swimming flume, i.e., a kind of swimming "treadmill". Oxygen uptake, heart rate, and blood lactate concentrations were measured in three female and six male adult subject, with varying proficiency in swimming, while subjects swam three styles at different speeds. The same determinations were made during exercise on a Krogh bicycle ergometer and on a treadmill. The same determinations were made in 12 girl swimmers, 13-18 years old, but only during maximal running and maximal swimming. Minimal oxygen uptake during floating in a vertical position in nine subjects varied from 0.9 to 2.0 I.min^-1. At a given swimming speed the trained swimmers were able to swim with a much lower oxygen uptake than subjects who were not trained swimmers. At a given oxygen uptake trained swimmers also swam much faster than the untrained swimmers. The front crawl proved to be the most economical style, as is the case in competition swimming. The back crawl was somewhat less economical and the breaststroke was the least economical style. Maximal oxygen uptake, maximal pulmonary ventilation, and maximal heart rate were significantly lower in swimming than in running or cycling, respectively.

11. Howley ET & Glover ME (1974): The caloric costs of running and walking one mile for men and women. Med.Sci.Sport Exerc. 6, 235-237.

Our purpose was to resolve the disagreement as to the number of calories expended per unit distance for walking and running. The caloric costs of walking and running one mile on a treadmill were calculated for eight men and eight women. The subjects walked at a speed of 82 +3 m/min (X+- SD) and ran at a speed that was regarded subjectively as comfortable. The average speed at which the mile was run was 195 +- 25 m/min for men and 137 +- 4 m/min for women. The average R measured during the walk was 0.86 and during the run 0.96. The gross caloric cost of walking was 1.08 +- 0.06 kcal/kg per mile for men and 1.15 +-0.08 kcal/kg per mile for women, and the cost of running was 1.57 +- 0.09 kcal/kg per mile for men and 1.73 +0.09 kcal/kg per mile for women. The running required significantly more kcal/kg per mile than walking (P<0.001) and the women used significantly more calories for both running and walking compared to the men (P<0.01). The net caloric cost of walking was 0.76 +- 0.07 kcal/kg per mile for men and 0.83 +- 0.08 kcal/kg per mile for women, and the cost of running was 1.43 +-0.08 kcal/kg per mile for men and 1.53 +- 0.09 kcal/kg per mile for women. The difference between the run and walk was highly significant (P<0.001) and the women used significantly more calories than men for both activities (P<0.05). Possible reasons for the small but statistically significant difference between men and women are discussed. It was concluded that running a given distance required more calories than walking the same distance.

12. Igbanugo V & Gutin B (1978): The energy cost of aerobic dancing. Res.Q. 49, 308-316.

The energy cost of three intensities of aerobic dance (low, medium, and high) was determined on four graduate students at Teachers College, Columbia University. All subjects danced seven 2-to 3-minute routines alternated with six 15- to 90-second recovery intervals of continuous walking. The dances were metabolically monitored with a Max Planck respirometer which measured ventilation and collected .06% sample of expired air, which was then analyzed for 02 and CO2 concentration. Values were expressed as VO2 I/minute, VO2 ml/kg/minute, and energy consumption as kcal/minute, and kcal/kg/minute. Heart rates were monitored by telemetry every minute throughout the dance. The women utilized 3.96 kcal/minute, 6.28 kcal/minute, and 7.75 kcal/minute, for the low, medium, and high intensity routines, respectively, while the men utilized 4.17 kcal/minute, 6.86 kcal/minute, and 9.44 kcal/minute, respectively. The energy expenditure for the low intensity routine was metabolically similar to walking on the level, that of the medium intensity routine to playing tennis, and that of the high intensity to playing hockey. Mean heart rates were 114, 145, and 156 beats per minute (bpm) for women; 106, 129, and 141 bpm for men. On the basis of these results, it is concluded that aerobic dance can be useful as a modality for cardiorespiratory training and rehabilitation, as well as weight reduction and maintenance.

13. Jette M & Inglis H (1975): Energy cost of square dancing. .J.Appl.Physiol 38, 44-45.

This experiment was concerned with determining the energy cost of two popular Western square dancing routines: the "Mish-Mash," which is a relatively fast-moving dance with quick movements, and the "Singing" dance, which is a slower and more deliberate type of dance. The subjects were four middle-aged couples, veteran members of a local square dancing club. Sitting and standing pulmonary ventilations were determined through the use of the Tissot gasometer. Kofranyi-Michaelis respirometers were employed for the dance routine ventilations.

These apparatus were fitted with a Monoghan neoprene cushion plastic mask. Gas samples were collected in polyethylene metallized bags and analyzed for O2 and CO2 content. The net energy cost for the two dances was appropriately summarized. The results indicated that for the males the net average energy cost of the Mish-Mash dance was 0.085 and 0.077 kcal/min per kg for the Singing dance. For the females, the cost was 0.088 and 0.084 kcal/min per kg, respectively. A net average cost of these two dances yielded a caloric expenditure of 5.7 kcal/min for a 70-kg male and 5.2 kcal/min for a 60-kg female. It was indicated that during the course of a typical square dance evening, a 70-kg man would expend some 425 kcal. while a 60-kg female would burn some 390 kcal. The energy cost of the dances studied were determined to be within the permissible work load of a functional class 1 patient with diseases of the heart as determined by the American Heart Association.

14. Jing L & Wenyu Y (1991): The energy expenditure and nutritional status of college students. I The energy cost and the total energy expenditure per day. Biomed.Environ.Sci. 4, 295-303.

The energy cost of major activities was determined in healthy students. Among the 606 medical students, 319 were males and 287 were females. Their ages ranged from 18 to 24 years. Douglas method was used to measure energy cost of each of a total of 42 activities, as well as that of the basal metabolic rates (BMR), resting metabolic rates (RMR) and the total energy expenditure per day under normal situations. The average RMR of male and female subjects were 0.669 +- 0.033 and 0.656 +- 0.030 kcal/sq.m/min respectively. The total energy expenditure per day of male students was 2706 kcal, and 2373 kcal for female students. The energy cost of single activities can be used as the basal data in studies of energy metabolism.

15. Lampley JH, Lampley PM & Howley ET (1977): Caloric cost of playing golf. Res.Q. 48, 637639.

The caloric cost of playing golf was measured in 11 men and 11 women. All subjects played the same nine holes and pulled a golf cart weighing approximately 14.kg. Expired air was collected for 15 seconds each minute during play, but no gas collections were made during a full swing due to limitations of the equipment. The measured energy costs were 4.2 + 0.6 kcal/kg/hr for men and 4.8 ± kcal/kg/hr for women, which was significantly higher (p < 0.05). These values are consistent with energy costs of playing golf reported by other investigators when expressed as net energy costs for 18 holes of golf.

16. Leger LA (1982): Energy cost of disco dancing. Res.Q.Exerc.Sport, 53, 46-49.

The purpose of this study was to evaluate the energy cost of dancing in the conditions that prevail in disco clubs. To avoid any hindrance in the movements of the dancers, oxygen uptake was assessed by retroextrapolating the O2 recovery curve to time zero of recovery. Males and females required a similar energy cost for disco dancing, that is 30.1 +- 10.3 ml O2.kg^-1.min^-1 for a fundamental music rhythm of 135.0 +- 7.7 bpm (X +- SD = for 15 university students). Males, being heavier than females, have a higher absolute energy expenditure (X +- SD = 48.5 +- 15.2 and 31.7 +- 13.7 kJ.min^-1). Heart rate was 134.5 +- 13.4 bpm. Total energy expenditure for a dancing evening (90 min of active time) was estimated to be 4350 and 2850 kJ for the males and the females respectively. At approximately 60 and 70% VO2 max for males and females respectively, disco dancing could be efficient for improving aerobic fitness and for controlling excess body fat. In this respect, and from the literature, disco dancing (rock and roll, hustle, twist, disco) appears almost twice as strenuous as square dancing and most other traditional dances (rumba, fox trot, waltz). The above figures are averages, and intra-individual variations of 3.0 ml.kg-1.min-1 (average difference between two trials) and inter-individual variations of 10.3 ml.kg1.min-1 (standard deviation) suggest caution before applying the average scores to any individual. Results reported above did not appear to be affected by the music rhythm, at least not for the range observed in this study (120-150 bpm). Indeed the energy cost of dancing on two music rhythms (128.0 +-8.9 and 140.0 +- 9.8 bpm) was not significantly different; furthermore, the correlation between the rhythm and the oxygen uptake was only r= 0.1.

17. Leger L & Mercier D (1984): Gross energy cost of horizontal treadmill and track running. Sports Med. 1, 270-277.

The gross energy cost of treadmill and track running is re-investigated from data published in the literature. An average equation, weighted for the number of subjects in each study, was found: VO2 (ml/kg/min) = 2.209 + 3.163 speed (km/h) for 130 subjects (trained and untrained males and females) and 10 treadmill studies. On the track, wind resistance as predicted by Pugh (1970) was added to the treadmill cost of running and yielded the following equation for adults of average weight and height: VO2 = 2.209 + 3.163 speed + 0.000525542 speed. Between 8 and 25 km/in, the following linear equation: VO2 = 3.5 speed (or met = km/in) was very close to the cubic equation. This linear equation for track running is, however, different from the treadmill linear equation, particularly for speeds over 15 km/in. This equation is also slightly different from the one published by Pugh (1970) for track running from 7 trained subjects only.

18. Maughan RJ & Leiper JB (1983): Aerobic capacity and fractional utilisation of aerobic capacity in elite and non-elite male and female marathon runners. Eur. J.Appl.Physiol 52, 80-87. The physiology of marathon running has been extensively studied both in the laboratory and in the field, but these investigations have been confined to elite competitors. In the present study 28 competitors who took part in a marathon race (42.2 km) have been studied; 18 male subjects recorded times from 2 h 19 min 58 s to 4 h 53 min 23 s; 10 female subjects recorded times between 2 h 53 min 4 s and 5 h 16 min 1 s. Subjects visited the laboratory 2-3 weeks after the race and ran on a motor driven treadmill at a series of speeds and inclines; oxygen uptake VO2 was measured during running at average marathon racing pace. Maximum oxygen uptake VO2 max) was measured during uphill running. For both males (r = 0.88) and females (r = 0.63), linear relationships were found to exist between marathon performance and aerobic capacity. Similarly, the fraction of VO2 max which was sustained throughout the race was significantly correlated with performance for both male (r = 0.74) and female (r = 0.73) runners. The fastest runners were running at a speed requiring approximately 75% of VO2 maxi for the slowest runners, the work load corresponded to approximately 60% of VO2 max. Correction of these estimates for the additional effort involved in overcoming air resistance, and in running on uneven terrain will substantially increase the oxygen requirement for the faster runners, while having a much smaller effect on the work rate of the slowest competitors. Five minutes of treadmill running at average racing pace at zero gradient did not result in marked elevation of the blood lactate concentration in any of the subjects.

19. Mayhew JL, Piper FC & Etheridge GL (1979): Oxygen cost and energy requirement of running in trained and untrained males and females. J.Sports Med. 19, 39-44.

The oxygen cost and energy requirement of submaximal treadmill running was assessed on trained (n=1) males and trained (n=5) and untrained (n=6) females. Open circuit spirometry was used to determine each subject's oxygen consumption during the final 2 minutes of 5-minute runs at 135, 150, 165, and 180 m/mint Two-way ANOVA was used to determine differences across speeds and subjects. Submaximal VO2 (ml/kg/min) was not significantly different among the four groups. Trained subjects, however, showed slightly greater efficiency than their untrained counterparts (5%). The VO2-running speed relationships were linear for all groups. Regression slopes and intercepts were not significantly different. Untrained females expended significantly more relative energy (kcal/kg/km) than untrained males, but no more than the two trained groups. The reason for this was perhaps a combination of greater relative fat content and inefficient running mechanics of the untrained females.

20. Padilla S. Bourdin M, Barthelemy JC & Lacour JR (1992): Physiological correlates of middle-distance running performance. A comparative study between men and women. Eur.J.Appl.Physiol 65, 561-566.

Centro Medicina Deportiva, Neudigonoza Amadeo Garcia Salazar S/U, Victoria-Gasteiz, Spain. To compare the relative contributions of their functional capacities to performance in relation to sex, two groups of middle-distance runners (24 men and 14 women) were selected on the basis of performances over 1500-m and 3000-m running races. To be selected for the study, the average running velocity (v) in relation to performances had to be superior to a percentage (90% for men and 88% for women) of the best French v achieved during the season by an athlete of the same sex. Maximal 02 consumption VO2max and energy cost of running (CR) were measured in the 2 months preceding the track season. This allowed us to calculate the maximal v that could be sustained under aerobic conditions, va,max. A v:va,max ratio derived from 1500-m to 3000-m races was used to calculate the maximal duration of a competitive race for which v = va,max (tva,max). In both groups va,max was correlated to v. The relationships calculated for each distance were similar in both sexes. The CR [0.179 (SD 0.010) ml.kg-1 x m-1 in the women versus 0.177 (SD 0.010) in the men] and tva,max [7.0 (SD 2.0) min versus 8.4 (SD 2.1)] also showed no difference. The relationships between VO2max and body mass (mb) calculated in the men and the women were different. At the same mb the women had a 10% lower CR than the men; their lower mb thus resulted in an identical CR. In both groups CR and VO2max were strongly correlated (r=0.74 and 0.75 respectively, P < 0.01), suggesting that a high level of VO2max could hardly be associated with a low CR. These relationships were different in the two groups (P < 0.05). At the same VO2max the men had a higher va,max than the women. Thus, the disparity in track performances between the two sexes could be attributed to VO2max and to VO2max/Cr relationships.

21. Pendergast DR, Bushnell D, Wilson DW & Cerretelli P (1989): Energetics of kayaking. Eur.J.Appl.Physiol 59, 342-350.

Department of Physiology, State University of New York at Buffalo 14214. The metabolic cost of paddling at low speeds (v) was measured from oxygen uptake VO2 and anaerobic glycolysis in an annular pool or calculated from submaximal VO2 measured at higher speeds when the kayaker was assisted in overcoming water resistance. Also calculated were the total drag (D) and the net mechanical efficiency (e). Each of the above variables was determined in male (n = 17) and female (n = 7) kayakers ranging in experience from beginners to elite. The VO2 increased with v to a peak of approximately 3.4 I.min-1 (80%-100% of peak VO2 during running) in men and of approximately 2.8 I.min-1 in women, while at higher speeds the additional energy was accounted for by anaerobic glycolysis. In all subjects the energy cost to paddle a given distance (C) increased according to a power function with increasing v. The C was lower for the elite male paddlers than for the unskilled group, while that for elite women was slightly less than that for the elite men. Also the rates of increase of C appeared to be inversely proportional to the subjects' skill. Total D for elite men increased from approximately 15 to 60 N over a range of speeds from 1 to 2.2 m.s-1 while those of unskilled men and skilled women for the same speed range were 10-20 N greater and slightly less, respectively. The e increased linearly, but at a different rate, with increases in v for the unskilled and the elite kayakers (males and females) being 4.2% and 6%, respectively, at v = 1.2 m.s-1.

22. Pendergast DR, di Prampero PE, Craig ABJ, Jr., Wilson DR & Rennie DW (1977): Quantitative analysis of the front crawl in men and women. .J.Appl.Physiol 43, 475-479.

Body drag, D, and the overall mechanical efficiency of swimming, e, were measured from the relationship between extra oxygen consumption and extra drag loads in 42 male and 22 female competitive swimmers using the front crawl at speeds ranging from 0.4 to 1.2 m/s. D increased from 3.4 (1.9) kg at 0.5 m/s to 8.2 (7.0) kg at 1.2 m/s, with D of women (in brackets) being significantly less (P < 0.05) than that of men. Mechanical efficiency increased from 2.9% at 0.5 m/s to 7.4% at 1.2 m/s for men, the values for women being somewhat greater than those for men. The ratio D/e was shown to be identical to the directly measured energy cost of swimming one unit distance, V02/d, and was independent of the velocity up to 1.2 m/s. It averaged 52 and 37 I/km for men and women respectively (P < 0.05). When corrected for body surface area the values were 27 and 22 I/km-m2 for men and women, respectively (P < 0.05). The underwater torque, T. a measure of the tendency of the feet to sink, was 1.44 kg-m for men and 0.70 kg-m for women (P less than 0.05). VO2/d increased linearly with T for both men and women of similar competitive experience. However, the proportionality constant delta VO2/d-delta T was significantly less for competitive than noncompetitive swimmers. The analysis of the relationship VO2/d vs. T provides a valuable approach to the understanding of the energetics of swimming.

23. Schantz PG & Astrand P (1984): Physiological characteristics of classical ballet. Med.Sci.Sport Exerc. 16,472-476.

The aerobic and anaerobic energy yield during professional training sessions ("classes") of classical ballet as well as during rehearsed and performed ballets has been studied by means of oxygen uptake, heart rate, and blood lactate concentration determinations on professional ballet dancers from the Royal Swedish Ballet in Stockholm. The measured oxygen uptake during six different normal classes at the theatre averaged about 35-45% of the maximal oxygen uptake, and the blood lactate concentration averaged 3 mM (N = 6). During 10 different solo parts of choreographed dance (median length = 1.8 min) representative for moderately to very strenuous dance, an average oxygen uptake (measured during the last minute) of 80% of maximum and blood lactate concentration of 10 mM was measured (N = 10). In addition, heart rate registrations from soloists in different ballets during performance and final rehearsals frequently indicated a high oxygen uptake relative to maximum and an average blood lactate concentration of 11 mM (N = 5). Maximal oxygen uptake, determined in 1971 (N = 11) and 1983 (N = 13) in two different groups of dancers, amounted to on the average 51 and 56 ml.min-1.kg-1 for the females and males, respectively. In conclusion, classical ballet is a predominantly intermittent type of exercise. In choreographed dance each exercise period usually lasts only a few minutes, but can be very demanding energetically, while during the dancers' basic training sessions, the energy yield is low.

24. Seliger V (1969): Energy expenditures during paddling. Physiologia Bohermoslovaka, 18, 4955.

Energy metabolism was assessed in 16 students of the Faculty of Physical Education during paddling in canoe-doubles on a tourist laminate canoe on a 1000m course. A similar examination was performed on 13 men and 13 women of the first grade during paddling in kayak-singles on a 500m course. In spite of the fact that the activity does not concern the whole body musculature, energy expenditure in canoeists was 9.7, and for paddling in kayaks was 33.8 in men and 16.6 kcal/min in women. The oxygen debt was 8.2 litres in men for kayak racing, which indicates the important role of anaerobic metabolism. This value was somewhat lower in women (4.5 litres). In canoeists the oxygen debt was 3.8 litres and this shows the greater anaerobic component of this performance. The pulse rate and especially the minute ventilation increases in kayak paddling almost to maximum values. It appears from these results that during training for high speed canoe paddling more attention should be paid to the development of the anaerobic capacity of the organism.

25. Snyder AC, O'Hagan KP, Clifford PS, Hoffman MD & Foster C (1993): Exercise responses to in-line skating: comparisons to running and cycling. Int.J.Sports Med. 14, 38-42.

Department of Human Kinetics, University of Wisconsin, Milwaukee 53201. A comparison of the physiological responses to in-line skating with the more traditional modes of exercise training has not been reported. The purpose of this study was to examine the physiological responses to inline skating compared with running and cycling. Nine trained volunteers (2 male, 7 female) performed 3-6 submaximal (30-90% VO2max workloads with each exercise mode. Oxygen uptake, heart rate and blood lactate were measured during each trial. Across the spectrum of oxygen uptakes studied, heart rate was higher with in-line skating than with cycling or running. At a lactate concentration of 4 mM, oxygen uptake was less for in-line skating and cycling than for running. Therefore, while in-line skating may be an effective mode of aerobic exercise, the training adaptations for in-line skating at 4 mM lactate may not be as great as for running, and at a given HR may be less than for running and cycling.

26. Toussaint HM, Knops W. de Groot G & Hollander AP (1990): The mechanical efficiency of front crawl swimming. Med.Sci.Sport Exerc. 22, 402-408.

Department of Exercise Physiology and Health, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands. In this study the gross efficiency of swimming was determined in a group of male (N = 6) and female (N = 4) competitive swimmers. The gross efficiency is defined as the ratio of the power output (W) to the power input (W). In a range of swimming velocities (0.95-1.6 m.s-1), the power input (rate of energy expenditure, 445-1137 W) was calculated from the oxygen uptake values (1.33-3.25 1 O2.min-1). The total power output (26-108 W) was directly measured during front crawl swimming using a system of underwater push-off pads instrumented with a force transducer (MAD-system). Using the MAD-system, the effect on total body drag due to the addition of the respiratory apparatus was evaluated to be negligible. The gross efficiency ranged from 5 to 9.5%. At equal swimming speed, the male competitive swimmers demonstrated a higher gross efficiency. However, this was due to the higher power output required by the male swimmers at a given speed. Gross efficiency was dependent on the absolute power output such that as power output increased so did the calculated gross efficiency. At the same power output, the values for the gross efficiency do not differ between the male and female competitive swimmers.

27. van Baak MA & Binkhorst RA (1981): Oxygen consumption during outdoor recreational cycling. Ergonomics, 24, 725-733.

The relation between oxygen consumption and cycling speed during outdoor recreational cycling was studied in 20 healthy subjects, men and women aged 20-30 and 50-60 years. They rode a touring bicycle at speeds between 2.8 and 8.3 m/s (10 and 30 km/hr). No significant differences in oxygen consumption were found between the sexes and two age groups. The scatter of the oxygen consumption data was least when oxygen consumption was expressed in terms of body surface. Different types of equations were developed for the prediction of oxygen consumption from the cycling speed which all gave approximately equally accurate predictions (VO2=0.137+0.0248V²; VO2=0.379-0.102V+0.0346V²; VO2=0.103V+0.00103V³; VO2 is oxygen consumption in l/min/m², V is cycling speed in m/s). The equation may also be applied for cycling in traffic situations if the mean speed is corrected for stop times.

28. Wigaeus E & Kilbom A (1980): Physical demands during folk dancing. Eur.J.Appl.Physiol 45, 177-183.

This investigation was undertaken to evaluate the aerobic demands during one of the most popular and demanding Swedish folk dances, the "hambo". Six men and six women, ranging in age from 22 to 32, participated. Their physical work capacity was investigated on a bicycle ergometer and a treadmill, using two to three submaximal and one maximal loads. All subjects were moderately well-trained and their average maximal oxygen uptakes on the treadmill were 2.5 and 3.7 I/min (42.8 and 53.2 ml/kg.min-1) for women and men, respectively. When dancing the "hambo" the heart rate was telemetered, and the Douglas bag technique was used for measurements of pulmonary ventilation and oxygen uptake. The physical demand during "hambo" dancing was high in all subjects. Oxygen uptake was 38.5 and 37.3 ml/kg.min-1 and heart rate 179 and 172 in women and men, respectively. Women used 90% and men 70% of their maximal aerobic power obtained on the treadmill. The pulmonary ventilation and respiratory quotient of the female subjects were lower when dancing as compared to running, possibly because of voluntary restriction of the movements of the thoracic cage. Some popular Scandinavian folk dances are performed at a speed and with an activity pattern resembling the "hambo", while others are performed at a slower pace. The exercise intensity used in "hambo" is more than sufficient to induce training effects in the average individual provided that the dancing is performed at the frequency and for length of time usually recommended for physical training. For older or less fit people dances with a slow pace can be used for training purposes.

29. Wilmore JH, Parr RB, Ward P. Vodak PA, Barstow TJ, Pipes TV, Grimditch G & Leslie P (1978): Energy cost of circuit weigh: training. Med.Sci.Sport Exerc. 10, 75-78.

The metabolic cost of circuit weight training was determined in a group of 20 men and 20 women, 17 to 36 years of age, who volunteered to participate in this study. Performing 3 circuits (10 stations/circuit), using a work (30-see) to rest (15-see) ratio of 2:1, and a total exercise time of 22.5 min. the energy expenditure was found to be highly related to body weight (r = 0.84 and r = 0.67 for men and women respectively). The average gross energy expenditure was 539.7 and 367.5 kcal/hr. (9.0 and 6.1 kcal/min) for the men and women respectively, but was 7.0 and 6.0 kcal/kg-hr when expressed relative to body weight, and 8.1 and 8.2 kcal/kg(LBW)-min when expressed relative to lean body weight. Thus, when body composition was considered, there were essentially no differences in the energy expenditure for males and females.

30. Zamparo P. Perini R. Orizio C, Sacher M & Ferretti G (1992): The energy cost of walking or running on sand. Eur.J.Appl.Physiol 65, 183-187.

Dipartimento di Scienze e Tecnologie Biomediche, Cattedra di Fisiologia, Udine, Italy. Oxygen uptake VO2 at steady state, heart rate and perceived exertion were determined on nine subjects (six men and three women) while walking (3-7 km.h-1) or running (7-14 km.h-1) on sand or on a firm surface. The women performed the walking tests only. The energy cost of locomotion per unit of distance (C) was then calculated from the ratio of VO2 to speed and expressed in J.kg1.m-1 assuming an energy equivalent of 20.9 J.ml 02-1. At the highest speeds C was adjusted for the measured lactate contribution (which ranged from approximately 2% to approximately 11% of the total). It was found that, when walking on sand, C increased linearly with speed from 3.1 J.kg-1.m-1 at 3 km.h-1 to 5.5 J.kg-1.m-1 at 7 km.h-1, whereas on a firm surface C attained a minimum of 2.3 J.kg-1.m-1 at 4.5 km.h-1 being greater at lower or higher speeds. On average, when walking at speeds greater than 3 km.h-1, C was about 1.8 times greater on sand than on compact terrain. When running on sand C was approximately independent of the speed, amounting to 5.3 J.kg-1.m-1, i.e. about 1.2 times greater than on compact terrain. These findings could be attributed to a reduced recovery of potential and kinetic energy at each stride when walking on sand (approximately 45% to be compared to approximately 65% on a firm surface) and to a reduced recovery of elastic energy when running on sand.

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1. Amundsen LR, Takahashi M, Carter CL & Nielsen DH (1980): Exercise response during wall-pulley versus bicycle ergometer work. Phys. Ther. 60, 173-178.

The purpose of this study was to test the significance of differences between cardiopulmonary responses to wall-pulley arm exercise and to bicycle ergometer leg exercise. The heart rate responses were greater for arm exercise than for leg exercise at comparable external work rates or energy cost levels. The systolic blood pressure responses and myocardial oxygen cost were greater for arm exercise at given external work loads, but not at comparable energy cost levels. The clinical and theoretical significance of these results is discussed.

2. Andrews RB (1967): The relative energistic efficiencies of one-armed and two-armed work. Hum. Factors, 9, 573-579.

The canon of work design that the two hands (arms) should work together was investigated for several levels of a dynamic task and of a static task. A comparison of one-armed and two-armed work was made in terms of the increase in the energy expenditure rate to accomplish the same external result. The findings showed that only at low levels of the dynamic task does the one-armed method possess an energetic advantage. At higher levels of the dynamic task and at all levels of static task, the increase in energy expenditure rate was lower for the two-armed method.

3. Asmussen E & Bonde Petersen F (1974): Apparent efficiency and storage of elastic energy in human muscles during exercise. Acta Physiol.Scand. 92, 537-545.

Three subjects ran on the treadmill (10 km/hr) against varying horizontal impeding forces. One subject was further studied during the same kind of walking and bicycling on the treadmill, and during work consisting in lowering and lifting the body by flexing and extending the legs from a standing or sitting position at varying frequencies, with or without rebound in the deepest position. Workpower (W kcal/min), and the corresponding steady state metabolic rate (E kcal/min, Douglas bag method) were measured. Apparent efficiency (N) was calculated as delta W/delta E * 100%. During load running N was 53.8, 37.6 and 41.2 %, respectively, in the 3 subjects. In the subjects more extensively studied N was: running 53.8, walking 32.3, bicycling 25.1, knee-flexions (deep or half) with rebound 39.4 or 41.0, without rebound 26.1 or 21.9%. These variations in N% were explained in accordance with the possibilities for re-using the energy, absorbed and stored in the muscles as elastic energy during a phase of negative excercise, in a subsequent phase of positive exercise. The condition of this is that the positive phase follows immediately after the negative. A calculation showed that during running 35-53% of the energy absorbed during the negative phase was re-used. Corresponding figures for walking and rebounding knee-extensions were 23% and 34% respectively, while in bicycling and knee-extensions without rebound all of the negative work degenerated into heat.

4. Auble TE, Schwartz L & Robertson RJ (1987): Aerobic requirements for moving handweights through various ranges of motion while walking. Physician Sportsmed. 15, 1 33-1 40.

This study compared the aerobic metabolic requirements of normal walking (without handweights and with normal arm motions) with requirements of walking while pumping 1-,2-, or 3-lb handweights through various ranges of motion. Nine male subjects walked with and without handweights at speeds of 1.12 to 1.79 m/sec. Adding handweighted arm movements significantly increased the oxygen consumption VO2 of normal walking by 2.1 to 25.5 ml.kg-1 .min-1, or 113% to 255% of normal walking requirements at any given speed. These results indicate that walking while moving handweights through large ranges of motion provides a combined upper and lower body aerobic stimulus that is sufficient for endurance training for persons with poor to excellent levels of aerobic fitness.

5. Balogun JA, Martin DA & Clendenin MA (1989): Human energy expenditure during level walking on a treadmill at speeds of 54-130 m min-1. Int.Disabil.Stud. 11, 71-74.

Department of Medical Rehabilitation, Obafemi Awolowo University, lle-lfe, Nigeria. Controversy exists in the literature as to the accuracy of the formulae used in predicting oxygen consumption VO2 during level walking. The purpose of this study was to develop an equation for use at speeds of 54-130 m min-1. The VO2 and energy expenditure (EE) of 25 healthy subjects were measured while walking on a level, motor-driven treadmill at four varying speeds (54, 81, 107 and 130 m min-1). The regression analyses revealed that a quadratic model was a better predictor (p less than 0.05) of both the VO2 and EE than a linear model. The quadratic equation relating VO2 and EE to walking speed (X) is as follows: VO2 (ml kg-1 min-1) = 17.77 0.3023X(m min-1) + 0.0027X2 (R2 = 0.935, SEE = 1.5) EE (kcal min-1) = 6.14 - 0.1076X (m min-1) + 0.00093X2 (R2 = 0.830, SEE = 0.89).

6. Balogun JA, Robertson RJ, Goss FL, Edwards MA, Cox RC & Metz KF (1986): Metabolic and perceptual responses while carrying external loads on the head and by yoke. Ergonomics, 29, 1623-1635.

The purpose of this study was to determine the metabolic efficiency and perceptual acceptability of transporting external loads on the head and by yoke. Ten young males (24.2 +- 3.9 years) of average physical fitness (VO2max=49.8 +- 6.5 ml.kg^-1.min^-1) walked for 6 min on a level motor-driven treadmill at 53.6,73,8 and 93,9 m.min^-1. Subsequently, all subjects carried external loads (11.6,16.1 and 20.6 kg) at the same speed using the headpack (HP), transverse yoke (TY) and frontal yoke (FY) modes of load carriage. Measurements were obtained for oxygen uptake VO2 I.min-1), local ratings of perceived exertion (RPE-L) and the overall perceived exertion (RPE-O). The VO2 was used in the computation of the metabolic efficiency VO2 ml kg total weight^-1 min^-1). Significant main effects (mode, load and speed) and three interaction effects (mode*load, mode*speed and load*speed) were obtained for metabolic efficiency. Scheffe post hoc analysis revealed that the metabolic efficiency for the TY and HP were greater than the FY while transporting the 16.1 and 20.6 kg loads at all walking speeds (p<0.05). No significant loss in metabolic efficiency was found while carrying the 20.6 kg load at 53.6 m min^-1. At 93.9 m.min-¹, all external loads transported were associated with a loss in metabolic efficiency. The RPE-L for the walking speeds and external loads were increased. The findings suggest that load transportation using the FY system is both physiologically and perceptually unacceptable.

7. Bassett DRJ, Giese MD, Nagle FJ, Ward A, Raab DM & Balke B (1985): Aerobic requirements of overground versus treadmill running. Med.Sci.Sport Exerc. 17, 477-481.

There is general agreement that the oxygen demand of level running is similar for both the treadmill (TM) and overground situations at speeds under 260 m X min-1. However, controversy exists with regard to inclined running. The prevailing view, represented by the ACSM prediction formulas, is that overground hill running is theoretically more costly than inclined treadmill running. This study was designed to investigate the problem from an empirical standpoint. Seven male subjects performed overground and TM running at two grades (0 and 5.7%) over a range of speeds between 136-286 m X min-1. For the outdoor trials, subjects covered a distance of 950 m at a constant pace, and expired gas was collected over the last 150 m. Matching trials were then performed on the treadmill at the same speed and % grade. Regression lines were calculated for speed vs oxygen consumption (VO2). For TM and overground level running, these were: VO2 (ml.kg-1.min-1)= 0.222 X speed (m.min-1) - 1.33 and VO2 (ml.kg- 1.min-1) = 0.202 X speed (m.min-1) + 3.21 respectively. The regression lines from TM and overground inclined running were: VO2 (ml.kg-1.min-1) = 0.237 X speed (m.min-1) + 7.53. and VO2 (ml.kg-1.min-1) = 0.233 X speed (m.min-1) + 7.78 respectively. A 2 X 3 X 2 ANOVA revealed that the differences between mean values for VO2 for level TM running vs level overground running and grade TM running vs grade overground running were not statistically significant (0.10 < P < 0.25). Therefore, it would appear that measurements of VO2 obtained during level and inclined TM running are valid when applied to the overground situation in the range of speeds considered in this study.

8. Beasley JC, Plowman SA & Fernhall B (1989): Effect of optimized and standard cycle ergometry on VO2max in trained cyclists and runners. Res.Q.Exerc.Sport, 60, 373-378.

This study compared the VO2 max obtained from optimized cycle ergometry (i.e. an ergometer with toe clips, racing seat, dropped handlebars, working at an rpm of 80-199) with those obtained from standard cycle ergometry and streadmill ergometry. Subjects were all trained runners or cyclists. Three maximal, continuous graded exercise tests were administered to each subject in a random order. Respiratory and metabolic data were collected continuously with an open-circuit automated system and stored on-line with an Apple III computer. Results showed that the only significant difference in maximal physiologic data was a higher VO2 max during treadmill ergometry than cycle ergometry for the runners. There were no group or test differences in absolute VO2 max during the two cycle ergometry tests. Both groups, however, achieved significantly greater workloads during the optimized ergometry test indicating a greater exercise economy. This was supported by subjects' self-assessment of the optimized test as easier. [not original abstract]

9. Berg K & Sady S (1985): Oxygen cost of running at submaximal speeds while wearing shoe inserts. Res.Q.Exerc.Sport, 56, 86-,39.

The energy expenditure of running while wearing normal training shoes and shoes with viscoelastic inserts was compared. Subjects were 15 highly trained runners. VO2 max was measured on a treadmill using open-circuit spirometry. Submaximal oxygen uptake was then determined at two running speeds of 241 and 268 m.min-1 at 0% grade with and without the inserts. Each test lasted six minutes. Results showed that oxygen uptake (I.min-1) while wearing the inserts only increased slightly (0.4% at 241 m.min-1 and 1.1% at 268 m.min-1. These differences were not significant. [not original abstract]

10. Bosco C, Montanari G. Ribacchi R. Giovenali P. Latteri F. lachelli G. Faina M, Colli R. Dal Monte A, La Rosa M, Cortili G & Saibene F (1987): Relationship between the efficiency of muscular work during jumping and the energetics of running. Eur.J.Appl.Physiol 56, 138-143.

The running economy of seventeen athletes was studied during running at a low speed (3.3 m X s1) on a motor-driven treadmill. The net energetic cost during running expressed in kJ X kg-1 X km-1 was on average 4.06. As expected, a positive relationship was found between the energetic cost and the percentage of fast twitch fibres (r = 0.60, n = 17, p less than 0.01). In addition, the mechanical efficiency during two different series of jumps performed with and without prestretch was measured in thirteen subjects. The effect of prestretch on muscle economy was represented by the ratio between the efficiency of muscular work performed during prestretch jumps and the corresponding value calculated in no prestretch conditions. This ratio demonstrated a statistically significant relationship with energy expenditure during running (r = -0.66, n = 13, P less than 0.01), suggesting that the elastic behaviour of leg extensor muscles is similar in running and jumping if the speeds of muscular contraction during eccentric and concentric work are of similar magnitudes.

11. Boyne AW, Brockway JM, Ingram JF & Williams K (1981): Modification, by tractive loading, of the energy cost of walking in sheep, cattle and man. J.Physiol. 315, 303-316.

1. A study was made in sheep and cattle walking on a treadmill, of the alteration to the energy expenditure that was caused by voluntarily exerted tension in the tether between animal and treadmill. 2. An additional experiment was carried out to investigate in human subjects walking on a treadmill, the alteration to the energy expenditure as a result of positive and negative tractive loads applied at waist level through a rope parallel to the plane of the treadmill. 3. Alterations to the net energy expenditure when walking were generally similar in the three species and varied with speed and gradient up to a maximum value of approximately 0.04 J per metre walked per gram of tension or negative load.

12. Brisswalter J & Legros P (1995): Use of energy cost and variability in stride length to assess an optimal running adaptation. Percept.Mot.Skills. 80, 99-104.

Laboratoire d'Analyse de la Performance Motrice Humaine, Universite de Poitiers, France. The aim of this study was to analyse how subjects' running adaptation was affected after a training overload. 14 middle-distance runners were tested before and after a training protocol of 15 days conducted only at one training pace. The efficacy this training protocol to improve energy cost of running was observed only at the training pace. This improvement was correlated with a particular systematic variation in stride length whereas no changes in stability of stride length were recorded. The data were interpreted in terms of specificity of training for which energy cost and stability of stride length could be considered criteria of an optimal adaptation to the training pace.

13. Brun T. Webb P & Blackwell F (1988): Energy expenditure over 24 hours, thermal comfort and fat-free mass in Asian men. Eur.J.Clin.Nutr. 42, 113-120.

Unite de Recherches sur la Nutrition et l'Alimentation, I.N.S.E.R.M. U-1, Hopital Bichat, Paris, France. Energy expenditure while sitting or sleeping was measured over 24 h in eight young Asian immigrants to France by a suit calorimeter and also by continuous measurement of respiratory gas exchange. Fat-free mass (FFM) was estimated from skinfold measurements. The energy intake per kilogram FFM of the Asians was similar to a group of well-off North Americans of larger body size but similar body composition who had been the subjects of an earlier study. In both groups thermoneutrality was controlled by adjusting the circulating water temperature of the suit calorimeter according to the subjects' preferences. The hourly energy expenditure/kg FFM was 1.2 kcal during sleep and 1.7 kcal while sitting. The mean energy expenditure/kg FFM during a quiet day was 37 kcal/d or 1.5 kcal/h. Using published equations, the estimated BMR was 1490 kcal (6.2 MJ). This estimated value agrees quite well with the BMRs of these subjects as previously determined. In the metabolic room the daily sedentary energy expenditure averaged 1.15 BMR and the energy intake averaged 1.26 BMR for the study subjects in free-living conditions in an urban environment. This is below the 1.4 X BMR currently recommended as a 'minimum' energy intake for subjects of low activity.

14. Bunc V, Sprynarova S. Parizkova J & Leso J (1984): Effects of adaptation on the mechanical efficiency and energy cost of physical work. Hum.Nutr.Clin.Nutr. 38, 317-319.

The improved economy of work which occurs as the result of adaptive processes, such as improved mechanical and metabolic efficiency, is investigated. The energy cost of running on a treadmill was measured in athletes of different specializations and type of training. The degree of adaption to running was measured by the gross mechanical efficiency calculated according to Komi et al (1981) and Ito et al (1983). The best mechanical efficiency was found in the middle-distance, endurance and marathon runners as compared to football players and pentathletes, who have adapted to different physical activities which are more intermittent in nature. Mechanical efficiency for the same activity was also measured in untrained subjects and found to about 18-20%.

15. Burdett RG, Skrinar GS & Simon SR (1983): Comparison of mechanical work and metabolic energy consumption during normal gait. J.Orthop.Res. 1, 63-72.

The validity of using mechanical measures of work to indicate the metabolic energy consumption during normal gait was examined. These mechanical measures were (a) mechanical work done on the center of mass per kilogram body mass per second (Wcm), calculated by integration of ground reaction forces measured by force platforms; (b) total body segmental work per kilogram body mass per second (Wseg), calculated from individual body segment energies measured by motion analysis; and (c) the sum of the normalized absolute moment impulses per second acting on the joints of the lower extremities (M), calculated from both force and motion data. The metabolic energy consumption, determined by analysis of expired air, and the three mechanical measures of work were calculated for six normal subjects walking at five speeds. Each measure of mechanical work per second walked was highly correlated with metabolic energy consumption/kg X s (r = 0.89 for Wcm, r = 0.79 for Wseg, and r = 0.85 for M), but a poorer correlation was found between each measure of mechanical work per meter walked and net metabolic energy consumption/kg X m (r = 0.54 for Wcm, r = 0.28 for Wseg, and r = 0.03 for M). These mechanical parameters, particularly when measured per time, may be useful in comparing metabolic energy consumption between individuals or between different walking conditions for the same individual.

16. Carroll Otto RM & Wygand J (1991): The metabolic cost of two ranges of arm position height with and without hand weights during low impact aerobic dance. Res.Q.Exerc.Sport, 62, 420423.

Human Performance Lab, Adelphi University, Garden City, NY 11530. To determine the energy cost of low impact aerobic dance while varying arm movement height and the use of hand weights, 10 adults volunteered to participate in four choreographed trials. All trials consisted of identical leg movements. Arm movements, however, were performed above shoulder level both with and without 0.9-kg hand weights and below shoulder level both with and without 0.9-kg hand weights. Open circuit spirometry was employed throughout the 10-min videotape guided trials, and heart rate was measured by telemetry. Neither the use of hand weights nor the change in arm position height significantly altered the energy cost of low impact aerobic dance. However, heart rate responses were significantly different. Caution should be observed by aerobics instructors and participants as to the use of heart rate as an indicator of intensity for low impact aerobic dance.

17. Cassady SL & Nielsen DH (1992): Cardiorespiratory responses of healthy subjects to calisthenics performed on land versus in water. Phys. Ther. 72, 532-538.

Physical Therapy Graduate Program, College of Medicine, University of Iowa, Iowa City 52242. This study evaluated the oxygen consumption VO2 and heart rate response curves for standardized upper- and lower-extremity exercise on land and in water. Forty healthy subjects performed one upper-extremity and one lower-extremity exercise at three selected cadences on land and in water. Steady-state heart rate was determined by electrocardiographic radiotelemetry and expressed as a percentage of age-predicted maximal heart rate (% APMHR). Percentage of age-predicted maximal heart rate was used as the criterion measure of relative exercise intensity. Oxygen consumption was determined by the open-circuit method. Results indicated systematic increases in VO2 from 2 to 9 metabolic equivalents (METs) (1 MET = 3.5 mL 02.kg-1.min-1) and % APMHR from 45% to 73% with increased cadence. The VO2 responses were highest during water exercise, whereas % APMHR was greater during land exercise. Based on the magnitude of the responses, water calisthenics appear to be of sufficient intensity to elicit training adaptations. Training studies are needed to document these changes.

18. Catlin MJ & Dressendorfer RH (1979): Effect of shoe weight on the energy cost of running. Med.Sci.Sport Exerc. 11, 80

Seven marathon runners with best times of 138 to 235 min for 42.2 km were studied during level treadmill running to determine the effect of shoe weight on energy expenditure. The runners alternately wore training flats or racing flats, each pair having an average weight of 0.87 kg and 0.52 kg, respectively. Oxygen consumption VO2 was measured while running at best marathon pace (201 to 303 m/min) after runs of 2 km road runs. VO2 averaged 44.1 ml/kg/min, or 72% of VO2max and was not affected by the duration of running. Mean energy expenditure was 0.51 kcal/min higher (p<0.05) with the heavier training flats; however, shoe weight had no significant effect on stride length. Total energy cost predicted for 42.2 km was 94 kcal (3.3%) greater with the training flats. It was concluded that shoe weight had only a small effect on the rate of total body energy expenditure while running at marathon racing speeds.

19. Cavanagh PR & Williams KR (1982): The effect of stride length variation on oxygen uptake during distance running. Med.Sci.Sport Exerc. 14, 30-35.

Ten recreational runners (mean VO2max 64.7 ml . kg-1 . min-1) underwent a 5-d acclimation period to treadmill running at a 7 min . mile-1 pace (3.83 m . s-1) for 30 min each day. During these runs their freely chosen stride lengths were determined and expressed as a percentage of leg length (%LL). On two subsequent testing days stride length was systematically varied over a range of +/- 20% LL about the freely chosen value. 02 uptake was determined by the Douglas Bag method. All subjects exhibited a stride length of which 02 uptake was minimized, although the individual profiles varied considerably. The mean increases in VO2 were 2.6 and 3.4 ml . kg-1 . min-1 at short- and long-stride length extremes, respectively. During unrestricted running, deviations from optimal stride length caused a mean increase in VO2 of 0.2 ml . kg-1 . min-1. The relatively efficient running patterns used by the subjects during unrestricted running indicate either an adaption to the chosen stride length through training or a successful process of energy optimization.

20. Consolazio CF, Nelson RA, Daws TA, Krzywicki HJ, Johnson HL & Barnhart MA (1971): Body weight, heart rate, and ventilatory volume relationships to oxygen uptakes. Am. J. Clin.Nutr. 24, 1180-1185.

The relationships of the various physiological work parameters have been evaluated as predictors of submaximal VO2 Although the correlation coefficients between heart rate and VO2 ml/kg per min were fair, the best relationships were observed between VE l/min and VO2 I/min at all work levels. Although in one instance body weight greatly improved the correlation coefficients between heart rate and VO2, this did not occur when the relationship between VE and VO2 ml/kg per min was utilized. The maximal versus submaximal work data in study 11 indicate that correlation coefficients and regression equations are observed with the heaviest workloads. [not original abstract]

21. Cooke CB, McDonagh MJ, Nevill AM & Davies CT (1991): Effects of load on oxygen intake in trained boys and men during treadmill running. .J.Appl.Physiol 71, 1237-1244.

Department of Sport and Exercise Sciences, University of Birmingham, United Kingdom. This investigation examines the effects of vertical and horizontal loading on the 02 intake VO2 response of children (n = 8) and adults (n = 8) to treadmill running. In unloaded running, the children required a significantly greater VO2 (P less than 0.001) than the adults [mean difference 7 ml.kg-1.min-1 (18.5%)]. There was no significant difference in the VO2 response of the children and the adults to either vertical or horizontal loading. Vertical loading with 5 and 10% of body mass did not produce a significant increase in the VO2 response of either group. In contrast, horizontal loading produced a significant increase (P less than 0.001) in both groups. The consistent response to the two forms of loading suggests that there is no difference between children and adults in the apparent efficiency of running with an external load. Stride frequency showed a significant increase with vertical loading (P less than 0.001) and a significant decrease with horizontal loading (P less than 0.001 ) in both groups.

22. Costill DL (1971): Energy requirements during exercise in the water. J.Sports Med. 11, 8792.

The purpose of this investigation was to compare the heart rate responses and work efficiency of exercise performed horizontally on land and in the water, and sitting on land. To this end, heart rate responses and energy requirements were compared among sitting-land, supine-land, prone-water and supine-water during submaximal and maximal cycling exercise. The work intensities tested under each condition were 450, 600, 900 kpm/min and a maximal work load. The maximal work loads achieved by the men exercising in water, maximal oxygen consumption, and maximal heart rates were significantly lower than those recorded on land. During cycling activity, water resistance was found to reduce substantially the working efficiency by approximately 4.0-5.8%.

23. Costill DL, Cahill PJ & Eddy D (1967): Metabolic responses to submaximal exercise in three water temperatures. .J.Appl.Physiol 22, 628-632.

Eight subjects were studied during 20 min of submaximal swimming in three different water temperatures (17.4, 26.8 and 33.1 C). During exercise and recovery various body temperatures, heart rates, and respiratory values were recorded. The energy requirements for the performance of exercise were not significantly affected by the water temperatures. Heart rates during recovery were found to be lowest following the exercise in 17.4 C water and highest after the swim in water at 33.1 C. The core temperature increase during exercise was positively related to water temperature.

24. Costill DL & Fox EL (1969): Energetics of marathon running. Med.Sci.Sports, 1, 81-86.

The metabolic responses VO2 and lactic acid accumulation) of six nationally ranked marathon runners were examined during submaximal and maximal treadmill running. At all running speeds the runners were confronted with a 242 m/min head wind to partially account for the actual air resistance experienced during competitive running. Based on the metabolic laboratory data and mean competitive running speeds, marathon performances were evaluated. The average max VO2 for the 6 runners was 4.54 I/min (71.4 ml/kg min). During a marathon race that requires about 2400 kcal it was estimated that the runners utilized 75% of their aerobic capacities with little lactic acid accumulation.

25. Cotes JE (1969): Relationships of oxygen consumption, ventilation and cardiac frequency to body weight during standardized submaximal exercise in normal subjects. Ergonomics, 12, 415427.

In normal males during submaximal exercise at a constant rate of external work on a bicycle ergometer or step test, the oxygen uptake and ventilation are linear functions of body weight. In normal females the oxygen uptakes do not differ materially from those for males of comparable weight. However, because of the constant terms in the regression equations, the convention of expressing results per kg body weight or m² body surface area may give rise to error; for ventilation this may be avoided by the use of the regression on oxygen uptake. Alternatively, the results may be reported at a constant oxygen uptake, for example, for men 1.5 I/min as recommended by l.L.O. and for women 1.0 I/min; the ventilation is then independent of body weight. By this procedure allowance is also made for differences in oxygen uptake due to the effects of practice. For the cardiac frequency a similar adjustment to a constant oxygen uptake yields values which are negatively correlated with body weight for walking on a treadmill, but not, in this instance, for standardized stepping and cycling.

26. Croisant PT & Boileau RA (1984): Effect of pedal rate, brake load and power on metabolic responses to bicycle ergometer work. Ergonomics, 27, 691-700.

In earlier investigations of energy cost of bicycle ergometer work, pedal rate and brake load have been varied simultaneously while maintaining a constant power, thus confounding the effects of these factors. A two-way factorial design was used to isolate the effects of rate and load upon metabolic responses during ergometer work while also determining any interaction of effects (a power effect). Nine men performed bicycle ergometer tests at five pedal rates (20-100 r.p.m.) with five brake loads at each rate (0-4 kp). Steady-state VO2 was found to be a quadratic function of brake load when pedal rate was held constant. There was a significant interaction between the effects of rate and load which resulted in a shifting of the most efficient rate-load combination as the power changed, Significant differences (10-29%) were found between rate-load combinations at a constant power. It was concluded that the energy cost of bicycle ergometer work is not linearly related to the work output, but rather depends on the rate and force with which the work is accomplished.

27. Davies CT (1980): Effect of air resistance on the metabolic cost and performance of cycling. Eur.J.Appl.Physiol 45, 245-254.

The metabolic cost (VO2) of cycling against a range of wind velocities (VW) was studied in a wind tunnel of 15 male cyclists and the results compared with work on a stationary cycle ergometer, uphill cycling on a treadmill, and performance times in road racing competitions. The results showed that VO2 at constant treadmill speed was proportional to V2W and was a linear function of work rate, both on the stationary ergometer and during uphill cycling on a motor driven treadmill. Maximal values of 5.04 1 x min-1 (69.3 ml x kg-1 x min-1) and 482 W were observed. The mean force (F) acting on the cyclists during the experiments in the wind tunnel was found to be equal to 0.0175 V2W x ms-1 (r = +0.98). The mean projected area (AP), drag areas (AD) and drag coefficient (CD) for the 15 cyclists were 0.50 m2, 0.280 m2, and 0.56 m2, respectively. During cycling out of doors on a calm day, VO2 was calculated to be a curvilinear function of the cyclists' speed of progression (V). The best guide to the cyclists' maximal aerobic power output VO2max was given by their 16.1 km (10 mile) time: VO2max (1 x min-1) = 4.219 + 0.7727 V (ms-1) r = +0.89. The results suggested that the relative aerobic power output (% VO2max which could be sustained for a given time by elite cyclists, is similar to that found previously for marathon athletes. However, due to the differences in the non-drag component of the work for given metabolic cost the cyclist will travel approx. 2 1/2 times the distance of an endurance athlete.

28. Davies CT & Sargeant AJ (1974): Physiological responses to standardised arm work. Ergonomics, 17, 41-49.

The physiological responses of 8 healthy male subjects were studied during one-and two-arm cranking exercise performed on a suitably modified bicycle ergometer under carefully standardised conditions utilising a shoulder restraining board and harness designed to restrict trunk movement. 'Apparent' mechanical efficiency (E-defined as the ratio of work performed to aerobic energy expended) was found to be similar at low levels of exercise to that previously found for leg work, namely 0.25; although there was a fall in E at levels in excess of ~40% VO2max V_E was higher in arm work than in leg work for a given VO2 or VCO2:Q, however remained the same for a given VO2 although stroke volume was reduced and cardiac frequency increased in arm work when compared with leg work. The maximum aerobic power of the arms was found to be 1/3 that of the legs, but for a given limb volume (muscle plus bone-measured after the method of Jones and Pearson (1969)) was ~13% higher in arm than in leg work: the reasons for this difference are discussed.

29. Davies CT, Sargeant AJ & Smith B (1974): The physiological responses to running downhill. Eur.J.Appl.Physiol 32, 187-194.

The metabolic cost of one healthy male subject aged 31 years, running on a range of gradients from +5% to -45% at speeds varying from 6.0 km.h-¹ to 18.0 km.h^-1, on a motor driven treadmill, has been investigated. The results showed that "apparent" efficiency of running increased with gradient from 0 to -15% and then remained fairly constant at a value similar to that found for downhill walking (see Davies and Barnes [6] of -1.2 until a gradient of -35% was reached. Beyond this gradient, there was a further rise in efficiency to reach -1.41 at -45%. The speed of running was controlled by stride length from 0 to -20%, but at higher gradients there was an increase in step frequency which was speed dependent. The relationships of V_E/VO2 and j_H/VO2 were similar to those previously described for downhill walking except that at gradients >-15% there was a parallel displacement of the f_h/VO2 to the right. The relationship of VO2 to speed of running uphill and downhill was essentially linear and thus for both forms of exercise, for a given gradient, the aerobic cost of running per unit distance covered was constant and independent of speed.

30. Davies CT & Thompson MW (1979): Estimated aerobic performance and energy cost of severe exercise of 24 h duration. Ergonomics, 22, 1249-1255.

The maximal aerobic performance VO2max and energy cost of running at various speeds of two ultra-distance athletes were measured in the laboratory on a motor driven treadmill and the results related to observations made during a 24 h race. The athletes finished 1 st and 2nd in the event and covered distances of 251.46 km and 234.56 km respectively during the 24 h period. From the measurements in the laboratory it was calculated that the average speeds sustained by the athletes during the competition were equivalent to an 02 cost of 36.4 ml.kg^-1.min^-1 and 35.3 ml kg -1 min-1 which represented approximately 50% of their VO2max During the race the winner expended an estimated 77,829 kJ (18,595 kcal) which is three times the highest recorded value in the most severe industrial work. By the nature of the activity this figure must be regarded as at or near the upper limit of sustainable energy expenditure by man during a complete uninterrupted 24 h circadian cycle.

31. de Looze MP, Toussaint HM, Nibbelke RJ & Eelderink HA (1992): Effects on efficiency in repetitive lifting of load and frequency combinations at a constant total power output. Eur.J.Appl.Physiol 65, 469-474.

Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands. Boxes were lifted and lowered repetitively at three different combinations of load and frequency. These combinations were chosen such that the total mechanical power generated was constant. Effects of the varying load or frequency conditions (but constant total mechanical power) on the rate of energy expenditure (M) and on the mechanical efficiency (ME) were measured. Mechanical power was determined from film analysis and separated into external power (generated to lift the load) and internal power (to raise the lifter's body mass). The M was determined from oxygen consumption measurements. The ME was calculated in two ways, depending on the definition of mechanical power, including either the external power only (MEext) or the total power output (MEtot). Despite a constant total mechanical power, M increased at higher loads and lower frequencies. This might be explained by the increasing isometric force required in postural and load control. The M increase resulted in a decrease of MEtot. However, at higher loads and lower frequencies MEext increased, indicating that more external work can be done at the same energy costs at higher loads or lower frequencies, which could be of interest from the point of view of occupational physiology. It would seem that at higher loads or lower frequencies the increased costs for isometric muscle action do not outweigh the benefit of raising the body less frequently. Furthermore, it was found that the MEext in lifting was much lower than the values reported for other kinds of activity. This was due to the large proportion of total power output that was internal power in repetitive lifting [eg 83.1 % (at a load of 6kg) in the present study].

32. di Prampero PE, Atchou G. Bruckner JC & Moia C (1986): The energetics of endurance running. Eur.J.Appl.Physiol 55, 259-266.

Maximal O2 consumption VO2max and energy cost of running per unit distance (C) were determined on the treadmill in 36 male amateur runners (17 to 52 years) who had taken part in a marathon (42.195 km) or semi-marathon (21 km), their performance times varying from 1.49 to 226 and from 84 to 131 min. respectively. VO2max was significantly (2p less than 0.001) greater /n the marathon runners (60.6 vs 52.1 ml . kg-1 . min-1) while C was the same in both groups (0.179 +/- 0.017, S.D., mlO2 . kg-1 . m-1 above resting), and independent of treadmill speed. It can be shown that the maximal theoretical speed in endurance running (vEND) is set by VO2max its maximal sustainable fraction (F), and C, as described by: vEND = F . VO2max . C-1. Since F was estimated from the individual time of performance, vEND could be calculated. The average speed of performance (vMIG) and vEND (m . s-1) were found to be linearly correlated: vMIG = 1.12 + 0.64 vEND (r2 = 0.72; n = 36). The variability of vMIG explained by vEND, as measured by r2, is greater than that calculated from any one regression between vMIG and VO2max (r2 = 0.51), F . VO2max (r2 = 0.58), or VO2max . C-1 (r2 = 0.63). The mean ratio of observed (vMIG) to theoretical (vEND) speeds amounted to 0.947 +/-0.076 and increased to 0.978 +/- 0.079 (+/S.D.; n = 36) when the effects of air resistance were taken into account. It is concluded that vEND = F . VO2max . C-1 is a satisfactory quantitative description of the energetics of endurance running.

33. di Prampero PE, Cortili G. Celentano F & Cerretelli P (1971): Physiological aspects of rowing. .J.Appl.Physiol 31, 853-857.

Heart rate, 02 uptake and lactic acid production together with the mechanical work performed have been investigated in man a) during simulated rowing in a basin and b) during actual rowing on a racing shell. Heart rate and O2 uptake are linearly correlated, the relationship being substantially the same for both simulated and actual rowing as for other forms of exercise. Pulmonary ventilation determined in simulated rowing is a linear function of VO2, the energy taken up by the muscles per liter of expired air being 0.26 _ 0.027 kcal. The mechanical efficiency is lower in simulated (0.1) than in actual (0.18) rowing at low stroke frequencies (<25). It approaches in both cases a maximal level of 0.2-0.23 at high frequencies (35/min). During actual rowing the mechanical power output necessary to maintain the boat progression as well as the energy expenditure appear to increase as the 3.2 power function of the average speed.

34. DiCarlo S & Leonardo J (1983): Hemodynamic and energy cost responses to changes in arm exercise technique. Phys. Ther. 63, 1585-1592.

The purpose of this investigation was to determine heart rate, blood pressure, rate pressure product, and oxygen consumption responses to variations in arm exercise technique of a specific calisthenics for cardiac rehabilitation. Eight subjects performed the following four variations of an arm calisthenics: slow paused, slow continuous, fast paused, and fast continuous. Heart rate, blood pressure, and metabolic cost were measured during the last minute of each variation. An analysis of variance revealed significant differences between exercise variations (p less than .05) across means in heart rate, blood pressure, rate pressure product, and metabolic equivalent terms. Post hoc analysis revealed that changes in technique caused significantly large differences (p less than .05) in heart rate, blood pressure, and rate pressure product, but metabolic equivalent term levels did not change significantly. Changes in arm exercise technique result in significant changes in heart rate, blood pressure, and rate pressure product with little or no changes in metabolic equivalent terms. This finding suggests that prescribing exercise based on metabolic equivalent terms may not be indicative of cardiac stress unless the technique of exercise is carefully monitored and controlled.

35. Duggan A (1988): Energy cost of stepping in protective clothing ensembles. Ergonomics, 31, 3-11.

This study investigated the effect of protective clothing ensembles (against chemical agent and cold water) on the energy cost of a bench stepping task (20 steps/min on a 0.305m high bench). Twelve male soldiers (Mean age 25.5 years; mean weight 75.4kg) performed the task at an ambient temperature of 10 degrees Celcius in each of the following clothing ensembles: A, military combat clothing:B, as A plus chemical agent protective clothing:C, as B plus long underwear and quilted thermal jacket liner;D, as C plus quilted thermal trouser liners. Determinations were made of oxygen consumption VO2 (as a measure of energy cost), heart rate (HR) and subjective rating of perceived exertion from the Borg scale (RPE). All variables showed a clear trend towards increasing with the amount of clothing worn and were significantly increased by the protective clothing ensembles (B. C and D). VO2(l/min) was 1.85, 1.99, 2.05 and 2,13 during stepping in Ensembles A,B and D, respectively. These increases were proportionately greater than the increases in clothing weight and external workrate. As a result, when corrected for clothed weight, VO2 was greater by an average of 9% in ensemble D than in ensemble A. This indicates that prediction of VO2 from external workrate will yield erroneous data for subjects wearing protective clothing ensembles. When protective clothing ensembles are worn, the increased energy cost of physical performance will reduce the time to the onset of fatigue and, because of the increased metabolic heat production, could exacerbate problems of heat dissipation and thus increase the risk of overheating. These factors should be taken into account when work must be undertaken in conditions demanding the use of such clothing.

36. Duggan A & Haisman MF (1992): Prediction of the metabolic cost of walking with and without loads. Ergonomics, 35, 417-426.

Army Personnel Research Establishment, MOD, Farnborough, UK. Measurement of the metabolic cost of walking inconveniences subjects, and requires skilled technical support and expensive equipment. These factors have stimulated interest in predictive equations. The present study assessed existing equations. Under each of 17 combinations of gradient (0-6%) and carried load (4.1-37.4 kg), 7-12 men undertook treadmill walking at 1.67 m/s. Measured oxygen consumption and respiratory exchange ratio were used to calculate metabolic rate (MRobserved). Metabolic rate was also predicted from the equation of Pandolf et al. (1977) (MRpandolf) and, where appropriate, from another five equations relating to walking without loads. MRobserved and MRpandolf did not differ significantly (p greater than 0.05) under any combination of gradient and load. The overall mean MRobserved and MRpandolf of 609 W and 6()2 W. respectively, also did not differ significantly (p greater than 0.05). These variables were highly correlated (r = 0.94) with a standard deviation about the prediction error of 47 W. For level walking without loads, the mean predictions from the equations of Pandolf et al. (1977) and Cotes and Meade (1960) did not differ significantly (p greater than 0.05) from the mean MRobserved of 428 Watts, but four other equations overestimated by 17-74 W. In conclusion, the Pandolf et al. (1977) equation has given good results across the range of combinations of load and gradient tested, and the errors are considered acceptable for most practical purposes.

37. Dutta SP & Taboun S (1989): Developing norms for manual carrying tasks using mechanical efficiency as the optimization criterion. Ergonomics, 32, 919-943.

The primary objective of this investigation was to determine optimum activity levels when carrying symmetrical loads in front of the body. Efficiency of mechanical work was used as the response variable for optimization purposes. This was defined as the ratio between the rate of energy transfer between and within body segments (Wwb) and the rate of net metabolic energy expenditure during the task (RNME). Response surface methodology was used to develop a model describing the relationship between the efficiency of mechanical work and three task related variables, i.e. load handled, frequency of handling and carrying distance. It was determined that a maximum efficiency of 31.74% is achieved under a combination of task conditions as follows: load = 16.72 kg; frequency = 3.64 handlings/min and carrying distance = 10.61 m. The implications of these findings are discussed in the paper.

38. Engels HJ, Smith CR & Wirth JC (1995): Metabolic and hemodynamic responses to walking with shoulder-worn exercise weights: a brief report. Clin.J.Sport.Med. 5, 171-174.

Exercise Science Laboratory, Wayne State University, Detroit, Michigan 48202, USA. This study examined the acute physiological responses to steady-rate walking with additional weight carried at shoulder level. Sixteen healthy subjects completed two treadmill walking bouts with and without a 4.54-kg shoulder-worn load carriage system in place. Addition of the external shoulder weights resulted in small increases in level walking oxygen uptake (+0.44 ml.kg-1.min-1; +0.03 L.min-1) and minute ventilation volumes (+0.81 L.min-1) (p < 0.05). RER values, heart rate (+3 beats.min1), and blood pressure responses [systolic blood pressure (SBP) + 4.5 mm Hg, diastolic blood pressure (DBP) + 1.3 mm Hg] were not significantly changed (p > 0.05). These findings indicate that the efficacy of shoulder-worn exercise weights to augment the physiological demand of walking exercise is marginal at best.

39. Epstein Y. Stroschein LA & Pandolf KB (1987): Predicting metabolic cost of running with and without backpack loads. Eur.J.Appl.Physiol 56, 495-500.

U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760-5007. In the past, a mathematical equation to predict the metabolic cost of standing or walking (Mw) was developed. However, this equation was limited to speeds less than 2.2 m.s-1 and overestimated the metabolic cost of walking or running at higher speeds. The purpose of this study was, therefore, to develop a mathematical model for the metabolic cost of running (Mr), in order to be able to predict the metabolic cost under a wide range of speeds, external loads and grades. Twelve male subjects were tested on a level treadmill under different combinations of speed and external load. Speed varied between 2.2 to 3.2 m.s-1 using 0.2 m.s-1 intervals and external loads between 0-30 kg with 10 kg intervals. Four of the subjects were also tested at 2 and 4% incline while speed and load remained constant (2.4 m.s-1, 20 kg). The model developed is based on Mw and is proportionately linear with external load (L) carried as follows: Mr = Mw-0.5 (1- 0.01L) (Mw -15L-850), (watt). The correlation coefficient between predicted and observed values was 0.99 (P less than 0.01) with SER of 7.7%. The accuracy of the model was validated by its ability to predict the metabolic cost of running under different conditions extracted from the literature. A highly significant correlation (r = 0.95, P less than 0.02, SER = 6.5%) was found between our predicted and the reported values. In conclusion, the new equation permits accurate calculation of energy cost of running under a large range of speeds, external loads and inclines.

40. Farley GR & Hamley EJ (1979): Progressive changes in energy cost during a three-hour race-walk exercise. Br.J.Sports Med. 12, 176-178.

Twenty experienced race-walkers were exercised in a controlled routine walking at 11.6 km/hr continuously for 3 hr. alternately on a treadmill and a cinder track. Analyses of expired air samples taken at 30 min intervals were used to calculate average R.Q. and energy expenditure. R.Q. was found to decrease progressively from 0.92 to 0.66 in the 3 hr and remained at this level 30 min later. The mean energy cost rose from 46.2 to 55.4 kJ/min or 24.7 to 29.7 kJ/min.m2. The results indicate that this group probably experienced an elevation of aerobic activity as they utilized progressively more fat to satisfy metabolic demands and that R.Q. may be a good indicator for determining recovery after severe long duration exercise.

41. Ferretti G. Atchou G. Grassi B. Marconi C & Cerretelli P (1991): Energetics of locomotion in African pygmies. Eur.J.Appl.Physiol 62, 7-10.

Departement de Physiologie, Centre Medical Universitaire, Geneve, Switzerland. The energy cost of walking (Cw) and running (Cr), and the maximal 02 consumption (VO2max) were determined in a field study on 17 Pygmies (age 24 years, SD 6; height 160 cm, SD 5; body mass 57.2 kg, SD 4.8) living in the region of Bipindi, Cameroon. The Cw varied from 112 ml.kg-1.km-1, SD 25 [velocity (v), 4 km.h-1] to 143 ml.kg-1.km-1, SD 16 (v, 7 km.h-1). Optimal walking v was 5 km.h-1. The Cr was 156 ml.kg-1.km-1, SD 14 (v, 10 km.h-1) and was constant in the 811 km.h-1 speed range. The VO2max was 33.7 m1.kg-1.min-1, i.e. Iower than in other African populations of the same age. The Cr and Cw were lower than in taller Caucasian endurance runners. These findings, which challenge the theory of physical similarity as applied to animal locomotion, may depend either on the mechanics of locomotion which in Pygmies may be different from that observed in Caucasians, or on a greater mechanical efficiency in Pygmies than in Caucasians. The low Cr values observed enable Pygmies to reach higher running speeds than would be expected on the basis of their VO2max

42. Francis K & Hoobler T (1986): Changes in oxygen consumption associated with treadmill walking and running with light hand-carried weights. Ergonomics, 29, 999-1004.

Ten subjects (mean weight 66.5 kg and mean age 26 years) walked and ran for six minutes on a treadmill at 4.8, 5.6 and 8 km/hour carrying (1) no load, (2) 0.91 kg or (3) 1.81 kg in each hand. A statistically significant difference in oxygen consumption, expressed as milliliters of oxygen consumed per kg of total weight (person+load), was found between running (8 km/hour) with no load and running while carrying each of the two loads. In contrast, walking with these hand weights did not significantly alter oxygen consumption. Running with these weights increased the oxygen uptake by 1.8 ml/kg/min while carrying 0.91 kg and by 2.7 ml while carrying 1.81 kg. These relatively small but significant increases in oxygen uptake suggest that the aerobic benefits of using the weights while running are marginal and should be weighed against the possibility that additional stress might be placed on the lower extremities.

43. Freyschuss U & Melcher A (1978): Exercise energy expenditure in extreme obesity: influence of ergometry type and weight loss. Scand.J.Clin.Lab.lnvest. 38, 753-759.

Bicycle and treadmill exercise tests including oxygen uptake VO2 and heart rate (HR) determination were carried out on a total of thirty patients with obesity, seventeen of whom were reinvestigated after weight loss. During both types of work VO2 for a given load was higher when compared to healthy controls. The increase of VO2 was more marked when cycling was performed in sitting position than in supine. The mechanical efficiency of sitting bicycle exercise averaged 17.8% and was negatively related to the percentage overweight; the slope of the VO2/load regression line was slightly less in comparison to the controls, while no such difference was found during treadmill walking. After weight reduction the VO2/load regression line was skirted downwards, the slopes being unchanged, thus the mechanical efficiency improved. This study not only confirms the observation of a low mechanical efficiency of obese subjects but also demonstrates that the change is quantitatively related to the overweight. The lowered efficiency was caused by body mechanical factors and there was no support for an abnormal muscular efficiency.. Exercise tests should be combined with VO2 determination, if used to assess the circulatory capacity of obese subjects.

44. Fujii N & Nagasaki H (1995): Efficiency and proficiency of bimanual cranking: differences between two cranking patterns. Percept Mot.Skills. 80, 275-283.

Tokyo Metropolitan College of Allied Medical Sciences, Japan. The efficiency and motor proficiency of an arm ergometer exercise were evaluated for two different cranking methods, cranking in the forward and reverse directions. 8 young men participated. Their heart rates were measured as an index of energy consumption. The proficiency of elbow-joint motion was assessed in terms of its consistency (intrasubject variability in cycle period, peak velocity, and peak acceleration) and smoothness (perk cost). Heart rates and jerk costs were lower during exercise in the forward direction than in the reverse direction. These results suggest that improved efficiency accompanied improved motor proficiency in terms of smoothness of movement for arm ergometer exercises under different cranking conditions.

45. Gardner AW, Poehlman ET & Corrigan DL (1989): Effect of endurance training on gross energy expenditure during exercise. Hum.Biol. 61, 559-569.

We compared the effect of endurance exercise training on gross energy expenditure (GEE) during steady-state exercise in 20 younger men (31.2 +/- 0.6 years) and 20 middle-aged men (49.2 +/-1.1 years). The subjects trained for eight months. The training program consisted of three 45-min walking and jogging exercise sessions per week at an intensity of approximately 6085% of the heart rate at peak VO2 We administered bicycle ergometer tests at 0, 4, and 8 months into training. Participants exercised at a power output of 100 W for 10 min using a pedaling frequency of 50 rpm. We determined GEE (kcal/min) by measuring the oxygen consumption and respiratory exchange ratio. We found a significant reduction (p less than 0.05) in GEE (0.7-1.3 kcal/min) following 4 months of endurance training in both age groups, with a further reduction (p less than 0.05) noted in only the middle-aged group at month 8. We found no difference (p greater than 0.05) in GEE between the younger and middle-aged men. We conclude that chronic exercise may modify GEE during a submaximal exercise bout and that this adaptation is similar in magnitude in younger and middle-aged men.

46. Gardner AW, Poehlman ET, Sedlock DA, Corrigan DL & Siconolfi S (1988): A longitudinal study of energy expenditure in males during steady-state exercise. J.Gerontol. 43, B22-B25.

Exercise Physiology Laboratory, Purdue University. Our purpose was to investigate longitudinal changes in gross energy expenditure (GEE) of 20 middle-aged and older men during submaximal exercise in 1969 and in 1985. GEE (kcal/min) was estimated using the caloric equivalent for each liter of oxygen consumed at the measured respiratory exchange ratio during submaximal exercise. The men performed a 10-min submaximal cycle ergometer exercise test at a power output (PO) of 100 W. Pedalling frequency was 50 rpm. Results showed a significant 5.9% decrease in GEE (p less than .01) from 8.5 +/- 0.8 (M +/- SD) kcal/min in 1969 to 8.0 +/0.4 (M +/SD) kcal/min in 1985. In addition, the effects of chronological age and leisure time physical activity on GEE were assessed and found to be nonsignificant, although a significant decrease in GEE over time (p less than .02) was observed in both groups. The present results support a decrease in GEE in middle-aged and older men over the 16-year time period. Furthermore, this decrease in GEE persisted regardless of chronological age or leisure time physical activity status.

47. Garg A & Saxena U (1979): Effects of lifting frequency and technique on physical fatigue with special reference to psychophysical methodology and metabolic rate. Am.lnd.Hyg.Assoc.J. 40, 894-903.

A laboratory study was conducted (1) to evaluate the effects of lifting frequency and technique on maximum acceptable work loads using psychophysical measurement technique, and (2) to compare the physiological fatigue criteria of 5 Kcal/min with the psychophysical fatigue criteria by measuring the metabolic rates at maximum acceptable work loads determined by subjective estimates of physical fatigue. Six male college students were required to lift from the floor to a 0.5 m height for 40 minutes. Four levels of lifting frequency (3, 6, 9 and 12 lifts/min) and three different lifting techniques (free style, stooped back and straight-back, bent-knee) were employed. Oxygen consumption rates were measured at maximum acceptable work loads (and were reduced to STPD). Statistical analysis showed that the maximum work loads acceptable to the workers were significantly affected by both lifting frequency and technique. Maximum acceptable work loads increased with an increase in lifting frequency. Both the subjective estimates of physical fatigue and the metabolic energy expenditure rate favored the free style lifting technique. The measured metabolic rates were in agreement with the physiological fatigue criteria of 5 Kcal/min only for six of the twelve combinations of lifting frequency and technique. Use of the physiological fatigue criteria will result in more liberal standards of work load at low work paces, especially for the stooped back and the free style lifting techniques.

48. Geissler CA & Aldouri MS (1985): Racial differences in the energy cost of standardised activities. Ann.Nutr.Metab. 29, 40-47.

The assumption is currently made by international organisations that individuals of the same size living in the same environment and having the same mode of living will have the same energy requirements whatever their race. Reports of very low energy intakes are frequently doubted. To investigate possible racial differences the energy cost of standardised activities was measured in European, Asian, and African males under the same experimental conditions. Subjects were closely matched for height, weight and Quetelet index. The energy cost of each activity, Lying, sitting and standing, was significantly higher, by 10-17%, in Europeans as compared to Asians and Africans, between whom no differences were found. Whether these differences are morphological or metabolic is discussed. It is concluded that differences in energy requirements do exist over and above those due to body size and activity.

49. Ghosh AK, Mazumdar P. Goswami A & Khanna GL (1988): Aerobic-anaerobic transition level of Indian middle & long distance runners. Indian J.Med.Res. 88, 371-375. km/h

A study was carried out on 23 elite Indian runners (12 middle distance and 11 long distance runners) to assess the aerobic-anaerobic threshold level and also to compare them with international counterparts to enable the coaches and sports medicine specialists in using the anaerobic threshold (AT) concept more efficiently as a training tool in endurance events. The cardiorespiratory variables at maximum effort were determined during a graded protocol of running on a treadmill, starting from 10 km/h and increasing every 2 min at the rate of 2 km/in till exhaustion. The AT was considered from the ventilatory threshold (VT) measured by non-invasive gas exchange method. The maximum aerobic capacity of Indian middle and long distance runners, found to be 62.0 and 68.1 ml/kg/min respectively, were significantly lower than those of their international counterparts. The mean VO2 of the Indian middle distance runners at AT level was 49.9 ml/kg/min as compared to 58.0 ml/kg/min of the world class runners. The long distance runners also exhibited a lower VO2 at AT level as compared to international runners. It is concluded that, as the AT level is a well established determinant in distance running performance and as a significant improvement of maximum aerobic capacity VO2max may not be possible if the runners reach a plateau, more emphasis should be given to improve the AT level of Indian distance runners.

50. Gite LP & Yadav BG (1990): Optimum handle height for a push-pull type manually-operated dryland weeder. Ergonomics, 33,1487-1494.

A laboratory study was carried out at the Central Institute of Agricultural Engineering (CIAE), Bhopal to find out the optimum height for a push-pull type manually-operated dryland weeder from ergonomic considerations. Four handle heights, ie 0.6, 0.7, 0.8 and 0.9 of shoulder height (SH), were compared with eight subjects in a laboratory set-up which involved an application of 98 N horizontal push for operating the weeder. The observations made during the experiment were heart rate, ventilation rate, energy expenditure and rating of perceived exertion (RPE). The lowest heart rate and RPE were observed while working and 0.7 SH and lowest oxygen consumption at 0.8 SH. However, no significant differences were observed in the physiological cost and perceived exertion between working with 0.7 and 0.8 SH handle height. Working at 0.9 SH produced the highest heart rate and oxygen consumption and subjects perceived the work as very hard. A handle height of 0.6 SH proved too low for the subjects resulting in increased muscle fatigue and higher heart rate as compared to 0.7 and 0.8 SH. Based on the results of this experiment, and the available anthropometric data of Indian workers, a handle height of 100 cm is recommended for the push-pull type manually-operated dryland weeder under study.

51. Gleim GW & Nicholas JA (1989): Metabolic costs and heart rate responses to treadmill walking in water at different depths and temperatures. Am.J.Sports Med. 17, 248-252.

Nicholas Institute of Sports Medicine and Athletic Trauma, Lenox Hill Hospital, New York. Treadmill walking/jogging in water is a potentially useful therapeutic modality. Since energy costs of this activity are unknown, we compared oxygen consumption (VO2) of treadmill walking/jogging in water to a dry treadmill at speeds of 40.23 to 160.9 meters/min (m/m) in 13.4 m/m increments in 11 subjects. At speeds greater than or equal to 53.6 m/m, ankle depth, below knee, midthigh, and waist depth walking/jogging in water significantly elevated VO2 and heart rate (HR) above dry treadmill walking (P less than 0.05). At speeds greater than or equal to 134.1 m/m, VO2 of waist depth jogging was not significantly greater than dry jogging. These findings showed no gender specificity. Treadmill walking/jogging in waist depth water at temperatures of 30.5 degrees C and 36.1 degrees C was compared to dry treadmill walking in five subjects. The rate of increase of HR compared to VO2 was significantly greater at 30.5 degrees C than dry walking, and greater at 36.1 degrees C than 30.5 degrees C (P less than 0.05). Treadmill walking in water can double the oxygen cost of movement depending on the depth and speed, and the response to increasing speed is nonlinear. Water temperature affects the relationship of HR to VO2 at waist depth, suggesting that water temperature can add a significant thermal load to the cardiovascular system. Metabolic and cardiovascular demands of treadmill walking/jogging in water must be considered when using this modality since greater external work results at much lower speeds than on land.

52. Godin G & Shephard RJ (1973): Body weight and energy cost of activity. Arch. Environ. Health, 27, 289-293.

The effect of body weight (W) upon the oxygen cost of activity VO2 is analyzed with respect to the authors' data on stepping and bicycle ergometry, and Brown's result for five industrial activities. Net oxygen consumption is proportional to Wⁿ, where n=0 for activities with little body movement and 1.0 for activities with substantial body movement; the oxygen cost of unit work is also increased by inexperience and obesity. The new method for the standardization of energy costs is somewhat superior to the adjustment of gross VO2 by W^1.0 or W^0.75, particularly in light work; however, there remains a challenging percentage of undescribed interindividual variation in the oxygen cost of industrial activities.

53. Goss FL, Robertson RJ, Spina RJ, Auble TE, Cassinelli DA, Silberman RM, Galbreath RW, Glickman EL & Metz KF (1989): Aerobic metabolic requirements of simulated cross-country skiing. Ergonomics, 32, 1573-1579.

This study evaluated the aerobic metabolic requirements of simulated cross-country skiing. Five male subjects exercised on a cross-country skiing machine at 12 different arm and leg resistances and movement frequencies. Oxygen consumption VO2 ranged from 21.6 to 44.4 ml kg(-1) min(-1). The VO2 increased significantly (p less than 0.05) as the frequency of limb movement was increased. These data suggest that simulated cross-country skiing places a significant demand on the aerobic metabolic system and as such is a viable alternative to conventional cardiovascular exercise modalities.

54. Goss FL, Robertson RJ, Spina RJ, Auble TE, Cassinelli DA, Silberman RM, Galbreath RW & Metz KF (1989): Energy cost of bench stepping and pumping light handweights in trained subjects. Res.Q.Exerc.Sport, 60, 369-372.

Department of Instruction and Learning, University of Pittsburgh, PA 15261. Rhythmic pumping of light hand-held weights while walking or running has become a popular approach to total body aerobic exercise. The use of handweights (HW) in conjunction with walking and running significantly increases the energy requirement of a given locomotor speed and adds variety to the choice of modes when prescribing exercise regimens (Auble, Schwartz, & Robertson, 1987; Francis & Hoobler, 1986; Graves, Pollock, Montain, Jackson, & O'Keefe, 1987). Handweighted exercise can also be conveniently and accurately prescribed for use with other exercise modalities such as bench stepping (Goss, et al., 1987). Stepping up and down on a bench at varying frequencies while pumping handweights is a low-impact, space efficient form of total body aerobic exercise. However, little is known about the energy cost of this unique exercise modality. Such information is important if handweighted exercise is to be used in conjunction with bench stepping when prescribing both therapeutic and recreational training regimens. The purpose of this investigation, therefore, was to evaluate the energy cost associated with combined bench stepping and rhythmic pumping of light handheld weights.

55. Graves JE, Martin AD, Miltenberger LA & Pollock ML (1988): Physiological responses to walking with hand weights, wrist weights, and ankle weights. Med.Sci.Sport Exerc. 20, 265271.

College of Medicine, University of Florida, Gainesville 32611. To compare the blood pressure (BP) responses to exercise with 1.36 kg (3.0 lb) hand-held weights (HW), wrist weights (WW), and ankle weights (AW), 12 sedentary males (20.8 +/- 1.2 yr) completed three randomly assigned treadmill exercises at 75% maximum heart rate (HR) reserve. Systolic and diastolic BPs among HW (181.2 +/-21.9 and 73.2 +/- 7.9 mm Hg), WW (180.1 +/- 27.2 and 71.0 +/-10.1 mm Hg), and AW (183.8 +/- 26.8 and 71.7 +/- 7.8 mm Hg) were not significantly different (P greater than 0.05). When compared to exercise with no weights (NW), only the diastolic BP for HW was significantly different (+4.4 mm Hg, P less than 0.05). To evaluate the energy cost of exercise with HW, WW, and AW, subjects completed a fourth exercise at constant treadmill speed (6.3 +/0.3 km.h-1) and grade (6.3 +/- 1.4%). Oxygen uptake and HR responses were greater (P less than 0.01) for HW (30.4 +/- 0.8 ml.min-1.kg-1; 160.6 +/- 4.0 beats.min-1), WW (30.4 +/- 0.9 ml.min-1.kg-1; 159.7 +/- 4.6 beats.min-1), and AW (29.0 +/- 0.7 ml.min-1.kg-1; 154.6 +/- 4.4 beats.min-1) than for exercise with NW (26.6 +/- 0.7 ml-min-1.kg-1; 147.0 +/- 3.8 beats.min-1). Oxygen uptake and HRs for HW and WW were greater than for AW (P less than 0.05). Ratings of perceived exertion (Borg scale for NW (11.7 +/- 1.8), HW (12.1 +/- 2.0), WW (12.2 +/- 1.8), and AW (12.3 +/- 1.8) were not significantly different (P greater than 0.05). These data suggest that hand-gripping associated with HW exercise may be responsible for a slight elevation in diastolic BP. The use of 1.36 kg HW or WW increases the energy cost of walking exercise to a greater extent than 1.36 kg AW. The increased energy cost associated with HW, WW, and AW can occur with little change in ratings of perceived exertion.

56. Graves JE, Pollock ML, Montain SJ, Jackson AS & O'Keefe JM (1987): The effect of handheld weights on the physiological responses to walking exercise. Med.Sci.Sport Exerc. 19, 260-265.

To study the physiological responses to walking with hand-held weights (HWs), 12 untrained men completed three sub-maximal and two maximal treadmill tests. Heart rate, oxygen uptake, respiratory exchange ratio, ventilation, systolic blood pressure (BP), diastolic BP, rate pressure product, and rating of perceived exertion were significantly greater (P less than 0.01) when HWs were added to walking exercise performed at constant treadmill speed and grade. To evaluate whether the evaluated BP response was caused by HWs independent of exercise load, heart rate was held constant at 75% maximum heart rate reserve during the third submaximal test. Systolic BP (151.1 +/- 15.3 mm Hg vs 160.1 +/- 16.9 mm Hg) and rate pressure product (252.1 +/- 27.0 vs 237.3 +/- 25.1) were significantly greater (P less than 0.05) during exercise with HWs. Physiological responses to maximal exercise with and without 3-lb HWs were similar. The time to exhaustion, however, was reduced (P less than 0.01) with HWs (719.3 +/- 98.1 s with HWs vs 784.4 +/- 118.9 s without HWs). These data indicate that 3-lb HWs can increase the metabolic cost of training (1 MET, 7 to 13 b X min-1) and may be useful in exercise prescription for individuals who do not want to run or are limited in the speed at which they can walk. Due to the exaggerated BP response, caution should be used when prescribing HW exercise for patients where increasing afterload may be a problem.

57. Gregor RJ & Costill DL (1973): A comparison of the energy expenditure during positive and negative grade running. J.Sports Med.Phys.Fitness, 13, 248-252.

The purpose of this study was to compare the energy expenditure during positive and negative grade running. A group of ten highly conditioned runners was tested on three separate treadmill runs utilizing a +6% grade, 0% grade, and a -6% grade. All runs were of a seven minute duration at an average speed of 200 m/mint Variables measured were heart rate and oxygen consumption. It was found that the fractional utilization of the aerobic capacity varied from 44% (6% grade) to 78% (+6% grade). Energy requirements increased 40% (+6% grade) and decreased 27% (-6% grade) from horizontal values. The resultant positive to negative work ratio was 1.92:1. The findings of this study supplement previous research on positive and negative work and support the acquisition of additional knowledge in the area.

58. Hagberg JM & Coyle EF (1984): Physiologic comparison of competitive racewalking and running. Int.J.Sports Med. 5, 74-77.

Eight competitive racewalkers were studied to determine a) the speed where running and racewalking become equally efficient, b) if, at a similar VO2 the physiologic responses to submaximal exercise differ between running and racewalking, and c) if VO2 max can be attained during racewalking. The speed at which running and racewalking elicited the same VO2 (approximately 30 ml X kg-1 X min-1) was between 8 and 9 km X h-1. Racewalking was more efficient at slower speeds, and running was more efficient at faster velocities. When running and racewalking were compared at similar oxygen consumptions, heart rate, ventilation, perceived exertion, and respiratory exchange ratio responses were identical. During maximal exercise, running and racewalking resulted in a similar VO2 max (60.4 +/- 1.3 vs. 58.1 +/- 1.5 ml X kg-1 X min-1), heart rate (193 +/- 4 vs. 188 +/- 4 bpm), ventilation (130.6 +/- 5.9 vs. 126.3 +/6.6 I X min-1), and post-exercise blood lactic acid concentration (9.8 +/- 0.6 vs. 9.6 +/-0.7 mM). These results indicate that the speed where racewalking and running become equally efficient is similar to the crossover speed for conventional walking and running. Cardiovascular, respiratory, and perceptual responses during running and racewalking are the same during maximal exercise and during submaximal exercise at the same VO2

59. Hagberg JM, Mullin JP & Nagle FJ (1978): Oxygen consumption during constant-load exercise. .J.Appl.Physiol 45, 381-384.

Previous investigators have reported that oxygen consumption VO2 continues to rise after the initial 2- to 3-min transient period of exercise when work exceeds approximately 60% of VO2 max. The purpose of this investigation was to examine the possible causes of this slow rise in VO2 Eighteen subjects exercised for 20 min at 65% and at 80% of VO2 max on the bicycle ergometer. VO2 ventilation (VE), and respiratory exchange ratio were monitored by a continuous computer-based system. Blood lactate concentration and rectal temperatures were measured at 2-to 3-min intervals during the exercise. VO2 increased significantly from the 5th to 20th min of exercise in 81% of the tests at both levels of work intensity. The magnitude of the rise was not different for the two work loads. No evidence was found to support the lactacid explanation proposed for this rise. Increased temperature could account for 30% of the rise; the estimated cost of increased VE could account for 30 and 81 % of the rise at the two work loads. The sum of these factors could account for 60 and 111 % of the rise in VO2 at the 65 and 80% of VO2 max work loads.

60. Hagerman FC, Connors MC, Gault JA, Hagerman GR & Polinski WJ (1978): Energy expenditure during simulated rowing. .J.Appl.Physiol 45, 87-93.

Metabolic function was measured by open-circuit spirometry for 310 competitive oarsmen during and following a 6-min maximal rowing ergometer exercise. Aerobic and anaerobic energy contributions to exercise were estimated by calculating exercise 02 cost and 02 debt. 02 debt was measured for 30 min of recovery using oxygen consumption (Vo2) during light rowing as the base line. Venous blood lactates were analyzed at rest and at 5 and 30 min of recovery. Maximal ventilation volumes ranged from 175 to 221 1/min while Vo2 max values averaged 5,950 ml/min and 67.6 ml/kg min. Maximal venous blood lactates ranged from 126 to 240 mg/100 ml. Average 02 debt squalled 13.4 liters. The total energy cost for simulated rowing was calculated at 221.5 kcal assuming 5 kcal/l 02 with aerobic metabolism contributing 70% to the total energy released and anaerobiosis providing the remaining 30%. Vo2 values for each minute of exercise reflect a severe steady state since oarsmen work at 96-98% of maximal aerobic capacity. 02 debt and lactate measurements attest to the severity of exercise and dominance of anaerobic metabolism during early stages of work.

61. Heinert LD, Serfass RC & Stull GA (1988): Effect of stride length variation on oxygen uptake during level and positive grade treadmill running. Res.Q.Exerc.Sport, 59, 127-130.

Sixteen men were studied during 6-min bouts of motorized treadmill running at 230 m.min^-1 and 0% and 4% grade to compare VO₂ while using freely chosen stride lengths (CSL) and stride lengths approximately 8% shorter (SSL) and longer (LSL) than CSL. The study also attempted to determine whether stride length variations of these proportions altered VO₂ differently at the two grades. CSL were greater (p<.05) at 0% than 4% with mean values of 133.5 and 131.5 cm, respectively. Two-way ANOVA (stride x grade) with repeated measures yielded significant F values (p<.05) for the main effects of both stride length and grade but not for interaction between the two factors. Mean VO₂ values were 44.95 and 56.80 ml.kg^-1.min^-1 at 0 % and 4% grade, respectively. The Tukey w procedure was used for comparing the main effect means across both grades for the three stride lengths. These means were 50.94, 49.88, and 51.80 ml.kg^-1.min^-1 for SSL, CSL, and LSL, respectively, with the CSL mean significantly less than the SSL, and LSL means (p<.05). Stride length variations of approximately ±8% did not alter VO₂ differently at the two grades, and although VO₂ for SSL and LSL was not different, VO₂ was significantly (p<.05) increased by 2.1% for SSL and 3.8% for LSL. Not all individual patterns followed the group norm, however, in that three subjects were more economical with short stride lengths and two were more economical with longer strides.

62. Hesser CM, Linnarsson D & Bjurstedt H (1977): Cardiorespiratory and metabolic responses to positive, negative and minimum-load dynamic leg exercise. Respir.Physiol. 30, 51-67.

Cardiorespiratory and metabolic responses to steady-state dynamic leg exercise were studied in seven male subjects who performed positive and negative work on a modified Krogh cycle ergometer at loads of 0, 16, 33, 49, 98, and 147 W with a pedalling rate of 60 rpm. In positive work, O₂ uptake increased with the ergometric load in a parabolic fashion. Net O₂ uptake averaged averaged 220 ml.min^-1 at 0 W (loadless pedalling), and was 75 ml.min^-1 lower at the point of physiological minimum load which occurred in negative work at approximately 9 W. The O₂ cost of loadless pedalling is for one-third attributed to the work of overcoming elastic and viscous resistance, the remaining part being due mainly to the work of antagonistic muscle contraction in the moving legs. Although at a given VO₂, work rate was much higher in negative than in positive work, corresponding values for VE were similar, suggesting that the mechanical tension in working muscles is of little or no importance in the control of ventilation in steady-state exercise. Heart rate increased linearly with VO₂ in both positive and negative work, with a steeper slope in negative work. Evidence is presented that none of the current definitions of muscular efficiency yields the true efficiency of muscular contraction in cycle ergometry, net efficiency calculation resulting in too low estimates, and work and delta efficiency calculations in overestimated values in the low-intensity work range, and in underestimated values in the high-intensity range.

63. Holmer I, Stein EM, Saltin B. Ekblom B & Astrand PO (1974): Hemodynamic and respiratory responses compared in swimming and running. .J.Appl.Physiol 37, 49-54.

In five healthy male subjects performing submaximal and maximal work in swimming and running, respectively, VO2 heart rate, and cardiac output (dye-dilution technique) were measured. O2 saturation, O2 and CO2 content, O2 and CO2 tensions, and pH of arterial and venous blood were determined during one submaximal and maximal work load. At a given VO2submax during swimming and running the cardiac output, stroke volume, and heart rate were similar. On an average VO2max was 15% lower, maximal cardiac output 10% lower, and maximal stroke volume about the same in swimming compared with running. Mean arterial blood pressure was higher during swimming. Arterial O2 tension was slightly higher during submaximal and maximal swimming compared with running. Systemic avDO₂ during maximal work was lower in swimming, while the O2 extraction from circulating blood in exercising leg was the same compared with running. V_E during maximal work averaged 111.0 and 154.2 I.min^-1 in swimming and running, respectively, while calculated alveolar ventilation averaged 101.8 in maximal swimming compared with 111.2 I.min^-1 in maximal running. Maximal values for blood lactate were similar in the two modes of exercise.

64. Holt KG, Hamill J & Andres RO (1991): Predicting the minimal energy costs of human walking. Med.Sci.Sport Exerc. 23, 491-498.

Department of Physical Therapy, Boston University, MA 02215. Preferred stride frequency (PSF) of human walking has been shown to be predictable as the resonant frequency of a force-drive harmonic oscillator (FDHO). The purpose of this study was to determine whether walking at the PSF and FDHO leads to minimal metabolic and mechanical costs. Subjects walked on a level treadmill at the PSF, FDHO, and frequencies above and below. Effects of stride length (SL) and speed (S) were assessed by two conditions, one in which SL was constant and the other in which S was constant. The predictability of PSF from resonance was replicated. Walking at the PSF and FDHO frequencies resulted in metabolic costs which were not significantly different (P > 0.05). A U-shaped oxygen consumption curve was observed with the minimum at the PSF and FDHO conditions when S was constant. A two-component curve in which a breakpoint was observed was found in the SL constant condition. A significant increase in metabolic cost was observed above the PSF/FDHO (P < 0.01). Internal work (power) values were not significantly different between walking frequencies for the S constant condition. In the SL constant condition, internal work values showed linear increases as frequency increased. It was concluded that PSF of walking arises from the interface of the resonance properties of the limbs as oscillators and the tendency of biological systems to self-optimize.

65. Hughes AL & Goldman RF (1970): Energy cost of "hard work". .J.Appl.Physiol 29, 570-572.

This study tests the hypothesis (based on data derived from a field study) that men working hard tend to adjust their work level to work at energy expenditures of 425 kcal/hr +- 10%, regardless of the terrain or load carried. Subjects carried loads ranging from 0 to 60 kg on a servo-controlled treadmill which automatically and imperceptibly adjusted its speed in response to changes in the progression rate of the subject. Subjects thus "hunted" an average progression rate for each load without being aware that they were making any adjustment whatever. Oxygen consumption was measured periodically during each trial. The results showed that: a) the average progression rate decreased nearly linearly with increasing load; b) the energy expenditure for the nonzero load conditions fell within the expected range of 425 kcal/hr +- 10%; c) the most economically carried loads under the conditions of this study were 30 and 40 kg.

66. Ito A, Komi PV, Sjodin B. Bosco C & Karlsson J (1983): Mechanical efficiency of positive work in running at different speeds. Med.Sci.Sport Exerc. 15, 299-308.

To investigate the possible role of elastic potentiation on mechanical efficiency, three male marathon runners were filmed while running on a treadmill at various steady-state speeds ranging from 7.0-22.0 km.h¹ Kinematic and mechanical energy analyses were performed from the film. Expired air was collected for energy expenditure determination. The analysis disclosed that during contact on the treadmill the knee and ankle joints initially had a phase of negative (flexion) angular velocity, followed by a positive velocity. In the hip joint the stretch-shortening cycle of the extensor muscles occurred primarily during the flight phase. The mean vertical and horizontal forces of the negative and positive phases of the contact period increased linearly with the increase in the running speed. The calculated mechanical efficiency of positive work was high but relatively constant (55.1 +/- 12.7%) across all speeds. The absolute contribution of the extra work, which comes from the stored elastic energy to the positive work, increased with running speed; however, its relative value (0.61 +/- 0.09 J.min¹.kg¹) remained constant at all measured speeds. It is suggested, therefore, that when the flight phase is included in the mechanical energy calculations, the measured efficiency for the positive work reaches a high but constant value in running at low-to-moderate speeds.

67. James R. Dukes-Dobos F & Smith R (1984): Effects of respirators under heat/work conditions. Am.lnd.Hyg.Assoc.J. 45, 399-404.

Physiological responses and perceived strain of five unacclimatized male subjects were studied. The subjects were exposed to heat during an exercise task and were evaluated while wearing half and full facepiece, cartridge-type, air-purifying respirators, and without a respirator. The exercise consisted of walking on a treadmill for a period of 1 hour in a controlled environmental chamber at each of two different energy expenditure levels (200 and 400 Kcal/hr) (approximately equal to 58 and 116 Watts) and two different heat exposures (air temperatures of 25 degrees C and 43.3 degrees C). The results indicated that wearing a full facepiece respirator imposed significant physiological strain added to that caused by the heat and workloads used in the study. Five of the six physiological measures show this increased physiological strain: heart rate; minute ventilation; oxygen consumption; energy expenditure; and oral temperature. There was no detectable effect on sweat rate. Although subjective ratings indicated more discomfort with increasing physiological strain, the observed correlations between such measures were low (Tb < 60). The net consequence of the significant effects indicates that workers tolerance to moderate or higher levels of work under hot conditions while wearing a respirator is reduced. The reduction is more pronounced when wearing a full mask than when wearing a half mask. Changes in respirator design which minimize respiratory dead space are suggested to alleviate this problem. Otherwise, prevention of excessive physiological strain from respirator use when working at moderate or higher levels at hot job sites could necessitate more rest breaks or limiting work time under such conditions.

68. Johnson AT (1976): The energetics of mask wear. Am.lnd.Hyg.Assoc.J. 37, 479-488.

Experimental data further defining the region of predominant respiratory stress is presented. Within this region, energy requirements of respiration increase disproportionately to the overall energy expenditure of the body as exercise intensity increases. Addition of a mask accentuates this tendency, especially since no physiological compensation is possible in mask parameters. Mask technology has improved masks to the point where they no longer dominate the man-mask system, but instead contribute resistances and dead volumes approximately equal to those naturally occurring in man. Modeling based on minimization of respiratory energy rate of expenditure in the human is applied to this man-mask system and predictions are made which to this point have been nearly impossible to obtain from experimental data.

69. Johnson BL, Stromme SB, Adamczyk JW & Tennoe KO (1977): Comparison of oxygen uptake and heart rate during exercises on land and in water. Phys. Ther. 57, 273-278.

Oxygen comsumption and heart rate response during identical calisthenic-type exercises performed on land and in the water were compared in eight subjects. Both the heart rate and the oxygen uptake were greater during exercises in water. Although gravity is the primary resistance to movement on land, viscosity friction and turbulence are dominant resistive factors in the water. The results of this study indicate that the latter two factors provide a greater load during exercise than the resistance of gravity in land exercises. At a moderate rhythm of leg exercises, oxygen consumption increased about ten times over resting values in the water for men subjects and about seven times for women. Arm exercise performed in the water require less energy than leg exercises in water, but arm exercises require significantly more oxygen when performed in water than the same exercises performed on land.

70. Jones BH, Toner MM, Daniels WL & Knapik JJ (1984): The energy cost and heart-rate response of trained and untrained subjects walking and running in shoes and boots. Ergonomics, 27, 895-902.

To determine the difference in the energy cost of walking and running in a lightweight athletic shoe and a heavier boot, fourteen male subjects (six trained and eight untrained) has their oxygen uptake VO2 measured while walking and running on a treadmill. They wore each type of footwear, athletic shoes of the subjects' choice (average weight per pair = 616g) and leather military boots (average weight per pair = 1776g), at three walking speeds (4.0, 5.6 and 7.3 km hour^-1) and three running speeds (8.9, 10.5 and 12.1 km hour^-1 ). The trials for running were repeated at the same three speeds with the subjects wearing shoes and these shoes plus lead weights. The weight of the shoes plus the lead weights was equal to the weight of the subjects' boots. The VO2 values with boots were significantly (p<0.05) higher (5.9-10.2%) at ail speeds, except the slowest walk, 4.0 km hour^-1. Also, VO2 with shoes plus lead weights were significantly (p<0.05) higher than shoes alone. Weight alone appeared to account for 48-70% of the added energy cost of wearing boots. The relative energy cost VO2 ml kg^-1 min^-1) of trained and untrained subjects were the same at all speeds. These data indicate that energy expenditure is increased by wearing boots. A large portion of this increase may be attributed to weight of footwear. In addition, the increased energy cost of locomotion with boots appears to place a limiting stress on untrained subjects.

71. Kamon E & gelding HS (1971): The physiological cost of carrying loads in temperate and hot environments. Hum.Factors, 13, 153-161.

Cartons weighing 10, 15 and 20 kg were carried by the hands in front of the body at speeds of 4 and 5 km/hr on level and at 4% grade at dry ambient temperatures of 20,35 and 45 C. Three pretrained subjects were used. Each test involved three 5-mint periods of carrying the load, walking without the load and sitting, repeated three times. At each speed, step rate increased with increase in the weight of the load, although the increase (but not total cost) was less when carrying uphill. Metabolic cost per total weight of body and load also increased with increase in the load; thus work efficiency decreased. The metabolic cost for each kilogram of load carried was 1.3 to 2.3 times greater than the cost per kilogram of body weight without load. No significant differences in metabolic cost were observed under the three thermal conditions, but heart rate increased about 7 to 10 beats/min for each 10 C-rise in air temperature. Heart rate increased progressively from first to third cycle when 20 kg were carried at 20 and 35 C; this was more obvious for uphill carrying. Such progressive rise in heart rate was most conspicious when the subject was carrying 15 and 20 kg at 45 C. Based on metabolic and cardiac cost, fatigue and need for rest pauses, 15-kg packages were determined to be preferable to 10-and 20-kg packages when large amounts of material must be moved by hand.

72. Kamon E, Metz KF & Pandolf KB (1973): Climbing and cycling with additional weights on the extremities. .J.Appl.Physiol 35, 367-370.

Fourteen male subjects climbed a 10° inclined laddermill at vertical speeds of 7.5, 10.5 and 14 m/min, without external load and with 5- to 10-kg loading: a) around the waist, b) around the ankles, and c) around the ankles and wrists. Multiple regressions of 02 uptake (ml/min) on the work rate (kpm/min) plus the total weight (kg) best fitted the data for the different treatments.

The only statistical difference was found between the regression for loading the extremities and that for no loading. However, the relative VO2 (ml/total weight per min) was linearly related to the climbing speed (S=m/min) only. For practical purposes one regression was calculated for all the pooled data, yielding: VO2 2.28 S + 5.4 +- 2.95. Some of the subjects pedaled on a cycle ergometer against increased resistance, with 10-kg external loading of the ankles. The extra 02 cost per unit of extra work load was found to be 1.34 and 1.44 ml/kpm for the respective pedaling rate of 50 and 75 rpm.

73. Karlsson J. Bonde-Petersen l=, Henriksson J & Knuttgen HG (1975): Effects of previous exercise with arms or legs on metabolism and performance in exhaustive exercise. .J.Appl.Physiol 38, 763-767.

The ability of additional muscles to perform after certain other muscles of the body had been exercised to exhaustion was studied in three male subjects. Exhaustive exercise was performed in two series: series L-A, a bout of leg exercise preceded a bout of arm exercise; series A-L, arm preceded leg (6-min recover) between bouts). Biopsies were taken during the course of each experiment from both the deltoideus and vastus lateralis muscles for determination of ATP, creatine phosphate, lactate, and pyruvate. Exhaustive exercise led to marked elevations in lactate and decreases in ATP and CP in exercised muscle and marked increases in blood lactate concentration. Similar changes, especially in lactate, were observed during and after the first exercise bout in nonexercised muscle. When arm or leg exercise was performed as the second bout, decreases in performance time were observed as compared to performance as the initial bout. It is suggested that the performance potential of muscle is decreased because of internal changes elicited by elevated blood lactate and/or blood H+ concentrations brought about by other muscle groups previously exercised to exhaustion.

74. Katch Fl, Freedson PS & Jones CA (1985): Evaluation of acute cardiorespiratory responses to hydraulic resistance exercise. Med. Aded.Sci.Sports Exerc. 17, 168-173.

Accurate evaluation of the acute responses to resistance exercise training depends on the stability of the criterion measures. This is particularly true for maximal effort exercise where continuous "all-out" effort for each repetition is encouraged. The present study evaluated reliability of repetition number (repN), respiratory gas parameters VO2 VCO2, VE), and heart rate (HR) for shoulder (SE), chest (CE), and leg (LE) exercise performed maximally on a single-unit, 3-station hydraulic resistance exercise machine (Hydra-Fitness, Belton, TX). On 2 separate days, 20 college men completed three 20-s bouts of SE, CE, and LE with a 20-s rest between bouts and 5 min between exercise modes. There were no significant differences between bouts or test days for repN, gas measures, or HR. Subjects performed 17, 19, and 21 reps during SE, LE, and CE. VO2 was 1.7 I.min-1 (24.3 ml.kg-1.min-1) for SE, 1.87 I.min-1 (25.5 ml.kg-1.min-1) for CE, and 2.1 I.min-1 (28.6 ml.kg-1.min-1) for LE. These values, averaged, represented 52.8% of the max VO2 determined on a continuous cycle ergometer test. The corresponding Hit's during hydraulic exercise averaged 84.6% of HR max. Test-retest reliability coefficients ranged from r = .67 to .87 for repN, r = .41 to .83 for gas measures, and r = .72 to .89 for HR. The MET level averaged 7.5 (heavy), and caloric expenditure per minute averaged 35% higher compared with literature values for free weights and 29.4 and 11.5% greater than circuit exercise on Nautilus or Universal Gym equipment, respectively. It is concluded that there are reliable individual differences in repN, respiratory gas parameters, and HR during maximal effort exercise of relatively short duration performed on a multiple-station hydraulic resistance exercise apparatus.

75. Kautz SA, Hull ML & Neptune RR (1994): A comparison of muscular mechanical energy expenditure and internal work in cycling. J.Biomech. 27, 1459-1467.

Biomedical Engineering Graduate Group, University of California, Davis 0021-9290. The hypothesis that the sum of the absolute changes in mechanical energy (internal work) is correlated with the muscular mechanical energy expenditure (MMEE) was tested using two elliptical chainrings, one that reduced and one that increased the internal work (compared to circular). Upper and lower bounds were put on the extra MMEE (work done by net joint torques in excess of the external work) with respect to the effect of intercompensation between joint torques due to biarticular muscles. This was done by having two measures of MMEE, one that allowed no intercompensation and one that allowed complete intercompensation between joints spanned by biarticular muscles. Energy analysis showed no correlation between internal work and the two measures of MMEE. When compared to circular, the chainring that reduced internal work increased MMEE, and phases of increased crank velocity associated with the elliptical shape resulted in increased power absorbed by the upstroke leg as it was accelerated against gravity. The resulting negative work necessitated additional positive work. Thus, the hypothesis that the internal work is correlated with MMEE was found to be invalid, and the total mechanical work done cannot be estimated by summing the internal and external work. Changes in the dynamics of cycling caused by a non-circular chainring may affect performance and must be considered during the non-circular chainring design process.

76. Keren G. Epstein Y. Magazanik A & Sohar E (1981): The energy cost of walking and running with and without a backpack load. Eur.J.Appl.Physiol 46, 317-324.

The effect of backpack load (20 kg) on oxygen consumption while walking and running at different speeds was investigated. Fifteen males walked and ran (with and without load) up a 5% sloped treadmill at 6.4, 7.2, 8.0, 9.6, and 11.2 km/in (4, 4.5, 5, 6, and 7 mph). While walking VO2 rose at a rate of 0.6 (I/min)/(km/h) and while running 0.3 (I/min)/(km/h). The mean oxygen consumption at the various speeds was 28.65, 33.78, 40.64, 46.84, 54.48 ml 02/kg BW/min, respectively, for the whole group without load and 26.52, 32.26, 38.28, 44.26, 48.16, respectively, with load. The breaking point between walking and running was at about 8.2 km/in. Carrying the load increased VO2 at a constant rate, and induced a breaking point between walking and running at a significantly lower speed for the smaller subjects than for the more robust ones. The results indicate that for certain tasks involving endurance and heavy load carriage, people should be selected according to criteria which integrate aerobic capacity and anthropometrical features.

77. Kyrolainen H. Komi PV & Belli A (1995): Mechanical efficiency in athletes during running. Scand.J.Med.Sci.Sports, 5, 200-208.

Department of Biology of Physical Activity, University of Jyvaskyla, Finland. The purpose of this study was to compare the external mechanical efficiency (ME) between power-trained athletes (n = 5) and endurance-trained athletes (n = 5). The relationships between biomechanical variables and metabolic cost were also investigated. The subjects ran at 3 different speeds (2.50 m.s-1, 3.25 m.s-1 and 4.00 m.s-1) both on the treadmill and on the track. The external work of the subjects was determined by a kinematic arm, and energy expenditure was determined by measuring oxygen consumption and respiratory exchange ratio. Biomechanical parameters included ground reaction forces, angular displacements of the knee and ankle joints and electromyography (EMG) of the selected muscles. The mean ME (+/- SD) values during running on treadmill were as follows: 49.6 +/- 8.9%, 60.1 +/- 9.6% and 61.2 +/- 10.4% for the endurance group, and 47.1 +/- 3.7%, 52.0 +/- 4.3% and 57.4 +/- 5.5% for the power group. In running on the track the respective values were 57.5 +/- 11.9%, 51.5 +/- 6.1% and 62.2 +/ 9.2% for the endurance group, and 47.0 +/- 8.3%, 45.3 +/- 10.2% and 60.0 +/- 5.9% for the power group. The subject groups did not differ significantly in ME due to high interindividual variance among both subject groups. The metabolic responses such as heart rate, pulmonary ventilation and oxygen uptake differed clearly between the athletic groups but this was not the case for the most of the biomechanical variables (such as EMG, step length and vertical displacement of the centre of the gravity). In conclusion, physiological and biomechanical variables appear to affect ME in a very complex way. In other words, efficiency is related individually to the sum of many variables.

78. Lacour JR, Padilla-Magunacelaya S. Barthelemy JC & Dormois D (1990): The energetics of middle-distance running. Eur.J.Appl.Physiol 60, 38-43.

Laboratoire de Physiologie - G.l.P. Exercise, Faculte de Medecine, Saint-Etienne, France. In order to assess the relative contribution of aerobic processes to running velocity (v), 27 male athletes were selected on the basis of their middle-distance performances over 800, 1500, 3000 or 5000 m, during the 1987 track season. To be selected for study, the average running velocity (v) corresponding to their performances had to be superior to 90% of the best French v of the season. Maximum 02 consumption VO2max and energy cost of running (C) had been measured within the 2 months preceding the track season, which, together with oxygen consumption at rest (VO2rest) allowed us to calculate the maximal v that could be sustained under aerobic conditions: vamax = VO2max - VO2rest) x C-1. The treadmill running v corresponding to a blood lactate of 4 mmol.l-1 (vla4), was also calculated. In the whole group, C was significantly related to height (r = -0.43; P less than 0.03). Neither C nor VO2max (with, in this case, the exception of the 3000 m athletes) were correlated to v. On the other hand, vamax was significantly correlated to v over distances longer than 800 m. These v were also correlated to vla4. However vla4 occurred at ,37.5% SD 3.3% of vamax, this relationship was interpreted as being an expression of the correlation between vamax and v. Calculation of vamax provided a useful means of analysing the performances. At the level of achievement studied, v sustained over 3000 m corresponded to vamax. The duration of the event raised the question of a possible change in C as a function of v during middle-distance running competitions.

79. Lammert O & Hansen ES (1982): Effects of excessive caloric intake and caloric restriction on body weight and energy expenditure at rest and light exercise. Acta Physiol.Scand. 114, 135141.

The individual response to overeating and semistarvation on energy expenditure at rest and light work before and after a test meal was investigated. This response was related to the change in dry body weight, measured as weight (W) minus total body water (TBW). Experiments were performed on 9 non-obese subjects: (a) with a normal habitual energy intake; (b) (overfeeding) with an extra energy intake of 12 MJ per day for two weeks; and (c) (semistarving) with an energy intake of only 2.1 MJ per day for 2 weeks. Measurements of VO2 VCO2, W and TBW were obtained at the end of each of the three periods. It was found that the perturbation in energy intake from normal to 20-25 MJ per day increased the energy expenditure. The magnitude of this increase was highly individual and inversely related to the change in dry body weight. Energy expenditure, measured under the four standardized conditions, after 2 weeks of starvation was lower than that obtained after the preceding overeating period. This decrease was also roughly inversely related to the change in dry body weight. The results support the idea that part of the regulation of body energy content takes place by way of a change in the efficiency of energy utilization and that the response to a perturbed energy intake varies considerably between subjects.

80. Legg SJ, Dziados J. Mello R. Vogel J & Doherty T (1988): Prediction of the metabolic cost of exercise from measurements during recovery. Aviat.Space Environ.Med. 59, 417-421.

U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts. This study was designed to determine if post exercise recovery measurements could be used to predict oxygen uptake VO2 minute ventilation (VE) and heart rates (HR) during exercise. VO2 VE and HR were measured in 11 healthy males during the last minute of treadmill running and during standing recovery. Since it is often impractical to collect data during the first 15 s of recovery in the field, the equations which best predicted the observed last-minute exercise values were obtained from enhanced linear least squares regressions of data collected between 15 and 60 s after cessation of exercise. In a separate validation experiment the mean (S.E.) difference between predicted and observed values for VO2 VE, and HR were 0.08 (0.06) L.min-1, 1.0 (5.1) L.min-1, and 2.2 (1.4) beats.min-1, respectively. We conclude that the equations described in this study may be used to estimate the metabolic cost of exercise in situations where it is impossible to make direct measurements.

81. Legg SJ & Mahanty A (1985): Comparison of five modes of carrying a load close to the trunk. Ergonomics, 28, 1653-1660.

This study was designed to investigate the cardiorespiratory, metabolic, and subjective response to carrying a load close to the trunk in five different ways. Each of five subjects carried a load equivalent to 35% body weight (BOO) for one hour at 4.5 km.hr^-1 and 0% grade on a motor driven treadmill using each of the following modes of load carriage: (1) the total load carried in a backpack with frame (BP/F), (2) the total load carried in a backpack with no frame (BP/NF), (3) half the load in a backpack (with frame) and half in pouches attached to a waist belt (BP/WB), (4) half the load in a backpack (with frame) and half in a front pack on the chest (BP/FP), and (5) the total load carried as a trunk jacket (TJ), i.e. a military type 'flak' jacket with weights inserted In pockets evenly distributed about the trunk. There were no statistically significant differences in the mean cardiorespiratory and metabolic costs associated with each of the five modes of load carriage. However, BP/FP and TJ were subjectively rated as significantly (P<0.01) more comfortable than BP/F and BP/NF, suggesting that there may be physiological differences between the five modes of load carriage which were not detected by cardiorespiratory and metabolic measurements used in this study (i.e. heart rate, oxygen consumption and minute ventilation). In contrast, the BP/FP was reported to be the hardest to don and doff and was associated with a statistically significant (P<0.05) restrictive type of ventilatory impairment. In conclusion, in practical terms there may seldom be a single 'beet' way to carry a 35% BW load close to the trunk.

82. Legg SJ & Mahanty A (1986): Energy cost of backpacking in heavy boots. Ergonomics, 29, 433-438.

Previous studies have investigated the oxygen cost VO2 of increasing boot weight during unloaded walking or running, and have shown that for each 100 9 increase in weight of footwear there is a 0.7-1.0% increase in VO2 In reality (except in athletic events) the use of heavy footwear is associated with load carriage, usually backpacking. We therefore investigated the effect of increasing boot weight by 5% of body weight on the VO2 of backpacking a load amounting to 35% of the body weight in five young males who walked at 4.5 km/hour (0% grade) on a motor-driven treadmill. The results indicated a mean increase of 0.96% in VO2 whilst backpacking for each 100-g increase in boot weight. In contrast the oxygen cost of increasing the backpack load was only 0.15% indicating that it was 6.4 times more expensive to carry weight on the feet as compared to the back. It is concluded that the relation between boot weight and oxygen cost, previously developed for unloaded walking and running, can reasonably be extended to include heavier boots and backpacking.

83. Legg SJ, Ramsey T & Knowles DJ (1992): The metabolic cost of backpack and shoulder load carriage. Ergonomics, 35, 1063-1068.

Army Personnel Research Establishment, Farnborough, UK. Eleven healthy male volunteer soldiers (mean [SD] age 24.0 [2.8] years, stature 174.1 [5.2] cm, body weight 73.2 [10.8] kg, body fat 14.2 [5.0]% and maximal oxygen uptake 4.1 [0.4] 1 min-1) walked at 4.8 km h-1 on a motor driven treadmill for 5 min at each of three gradients (0, 2.5 and 5%) whilst carrying a two-part 26 kg load either on each shoulder or strapped to a backpack frame. The load was made up of two cylinders, one weighing 18.4 kg and the other weighing 7.6 kg. For all treadmill gradients the mean (SD) backpacking heart rates and oxygen uptakes (0% gradient, 122 [103 beats min-1, 1.51 [0.11] 1 min-1; 2.5% gradient, 135 [10] beats min-1, 1.81 [0.13] 1 min-1; 5% gradient, 155 [7] beats min-1, 2.21 [0.11] 1 min-1) were significantly (p less than 0.001) lower than for shoulder load carriage (0% gradient, 130 [9] beats min-1, 1.70 [0.12] 1 min-1, 2.5% gradient, 147 [8] beats min-1; 2.01 [0.10] 1 min-1; 5% gradient 164 [9] beats min-1, 2.39 [0.11] 1 min-1). The relative oxygen cost of backpacking was 4.3-4.7% VO2 max lower than for shoulder load carriage. It is concluded that the metabolic cost of backpacking an asymmetric two part 26 kg load was significantly less than for shoulder load carriage when walking at 4.8 km h-1 on a treadmill over gradients of 0-5%. It is likely that under field conditions for this particular load soldiers may find the shoulder load carriage method acceptable for approximately 1-1.5 h but may tolerate the backpacking method for longer periods of time.

84. Lukin L, Polissar MJ & Ralston HJ (1967): Methods for studying energy costs and energy flow during human locomotion. Hum.Factors, 9, 603-608.

Methods are described for the metabolic cost of increased and diminished gravitational work done by the human subject during normal locomotion at various speeds and slopes on the treadmill. It is shown that the energy expenditure is a linear function of the gravitational work and, as long as the gait is of a smooth and natural character, appears to be dependent upon the true vertical lift per step multiplied by the number of steps per minute. The true vertical lift is defined as the lift resulting from muscular action, as contrasted with components due to treadmill motion. Methods are also described for recording vertical and translational motions of the torso during a single step, and for analyzing the flow of mechanical energy into and out of the torso during each phase of the walking cycle. Implications for calculation of efficiency are briefly discussed.

85. Marchetti M, Figura F & Ricci B (1980): Biomechanics of two fundamental sailing postures. J.Sports Med. 20, 325-332.

Three experienced sailors performed two fundamental body maneuvers to minimize capsizing during sail-boating. Cardio-pulmonary and metabolic responses for each position have been evaluated as well as muscular movements at relevant joints. The strenuous nature of extending the body outboard, without trapeze, requires considerable thigh and abdominal muscle force and endurance.

86. Martin BJ, Robinson S. Wiegman DL & Aulick LH (1975): Effect of warm-up on metabolic responses to strenuous exercise. Med.Sci.Sports, 7, 146-149.

Aerobic and anaerobic energy transformations were measured in two trained runners during 90-sec treadmill runs at 23.6 km/hr (:2% grade). The runs were preceded by rest or either of two warm-ups: 1) 15-min run at 10 km/hr, or 2) 15-min run at 10 km/hr followed by 3-min standing. Compared with runs without warm up, during the third half minute of runs following both types of warm-up 11 % greater heart rates ( HR), 8% greater oxygen consumption (Vo2), and unchanged ventilation were recorded. The rate constant of the approach of Vo2 to O2 in the first minute of work was unaffected by warm-up. Runs following either warm-up resulted in 25% lower lactate production; during these runs 3 to 4 degrees C higher gastrocnemius muscle temperatures (Tm) were maintained. The differences in HR, Vo2, and Tm continued throughout exhausting 5-min runs at 20.9 km/hr (2% grade). An elevated muscle temperature may therefore be requisite for the maximal aerobic response to a short exhausting run.

87. Mayhew JL (1977): Oxygen cost and energy expenditure of running in trained runners. Br.J.Sports Med. 11, 116-121.

The oxygen cost and energy expenditure of submaximal treadmill running was evaluated in 9 male distance runners. The oxygen consumption-running speed relationship was highly significant (r= .917) and linear over the entire aerobic range. The caloric cost of 0.97 Kcal/kg/km was in close agreement with values found in the literature and was independent of running speed. The caloric cost per unit distance and time increased with acceleration in running speed. The slope of the regression line of oxygen consumption on running speed appears to measure a different component of efficiency than the fractional utilization coefficient of aerobic capacity. There is apparently a wide variation in the oxygen cost of running in trained runners.

88. McMiken DF & Daniels JT (1976): Aerobic requirements and maximum aerobic power in treadmill and track running. Med.Sci.Sports, 8, 14-17.

Treadmill and track running comparisons were made on eight track athletes. Oxygen uptake VO2 during steady-state and maximum aerobic power VO2 max) were measured in a discrete series of three speeds, and at maximal effort. Running speeds were always in sequence from slowest to fastest. Expired air was collected from the runner by the Douglas-bag method, and analyzed by the Lloyd-Haldane technique. Neither VO2 max nor aerobic requirements of running were significantly different in track and treadmill determinations. There were several correlations: 1) VO2 max with body weight (r = .83 P less than .02), 2) treadmill and track determinations of VO2 max (r = .95, P less than .01) and 3) VO2 ml/kg with running velocity m/min (r = .91, P less than .01) where the regression was linear and may be represented by the equation Y = 5.36 + 0.172X, where Syx = 2.7 m102/kg. It is concluded that treadmill determinations of oxygen uptake may be validly applied to track running in calm air within the range of 180...260 m/mint

89. Menier DR & Pugh LGCE (1968): The relation of oxygen intake and velocity of walking and running, in competition walkers. J.Physiol. 197, 717-721.

1. The oxygen intake of four Olympic walkers was measured while walking and running at varying velocities on a treadmill at an altitude of 1800 m. 2. The relation between 02 intake and running at speeds between 8 km/hr and 21 km/hr was linear. The relation for walking at speeds up to 8 km/hr followed an upward concave curve. These findings were similar to results obtained at sea level by other investigators. 3. For walking at speeds between 8 km/hr and 14.5 km/hr the relation of 02 intake and velocity was a straight line having a slope twice that of running. 4. Maximum 02 intake in walking averaged 60.0 ml/kg/min (range 55.8-64.1 ml/kg/min) compared with 57.4 ml/kg/min (range 55.2-60.2 ml/kg/min) in running. An international class long distance runner serving as a control reached a maximum 02 intake of 70 ml/kg/mint

90. Miller JC, Farlow DE & Seltzer ML (1977): Physiological analysis of repetitive lifting. Aviat. Space Environ. Med. 48, 984-988.

It was hypothesized that physical factors associated with the act of lifting, and also known to adversely affect cardiovascular functions (e.g., increased intrathoracic and intra-abdominal pressures), would disturb the linear relationships normally noted among measures of cardiopulmonary variation during exercise. Data collected during repetitive lifting, performed on a unique ergometer (described in the paper), did not support the hypothesis. It was concluded that relationships among energy expenditure rate, pulmonary ventilation, heart rate, and workload were essentially linear through the range of lifting workloads from 1 to 50 W for 18 male Caucasians ranging in age from 21 to 55 years.

91. Minetti AK, Saibene F. Ardigo LP, Atchou G. Schena F & Ferretti G (1994): Pygmy locomotion. Eur.J.Appl.Physiol 68, 285-290.

Department of Muscle Physiology, I.T.B.A., C.N.R., Milan, Italy. The hypothesis that Pygmies may differ from Caucasians in some aspects of the mechanics of locomotion was tested. A total of 13 Pygmies and 7 Caucasians were asked to walk and run on a treadmill at 4-12 km.h-1. Simultaneous metabolic measurements and three-dimensional motion analysis were performed allowing the energy expenditure and the mechanical external and internal work to be calculated. In Pygmies the metabolic energy cost was higher during walking at all speeds (P < 0.05), but tended to be lower during running (NS). The stride frequency and the internal mechanical work were higher for Pygmies at all walking (P < 0.05) and running (NS) speeds although the external mechanical work was similar. The total mechanical work for Pygmies was higher during walking (I' < 0.05), but not during running and the efficiency of locomotion was similar in all subjects and speeds. The higher cost of walking in Pygmies is consistent with the allometric prediction for smaller subjects. The major determinants of the higher cost of walking was the difference in stride frequency (+9.45, SD 0.44% for Pygmies), which affected the mechanical internal work. This explains the observed higher total mechanical work of walking in Pygmies, even when the external component was the same. Most of the differences between Pygmies and Caucasians, observed during walking, tended to disappear when the speed was normalized as the Froude number. However, this was not the case for running. Thus, whereas the tested hypothesis must be rejected for walking, the data from running, do indeed suggest that Pygmies may differ in some aspects of the mechanics of locomotion.

92. Morgan DW, Martin PE, Baldini ED & Krahenbuhl GS (1990): Effects of a prolonged maximal run on running economy and running mechanics. Med.Sci.Sport Exerc. 22, 834-840.

Exercise and Sport Research Institute, Arizona State University, Tempe 85287. The purpose of this study was to document the effects of a prolonged (30 min) maximal run (PMR) on running economy (RE) and running mechanics in 16 male runners (mean VO2max = 59.0 +/-4.5 ml.kg1.min-1). After completing 60 min of treadmill accommodation, each subject performed two 10 min economy runs at 200 m.min-1. Subjects were also filmed at 100 fps during the last 30 s of each run in order to quantify 20 temporal, kinematic, and kinetic gait descriptors previously associated with RE variation. Following the second run, each subject completed the PMR at 85% of his predicted velocity at VO2max (89% VO2max). One, two, and four days after the PMR, subjects repeated the 10 min economy run. No significant difference (P greater than or equal to 0.05) in RE (range = 42.3-42.6 ml.kg-1.min-1) was observed following the PMR. Biomechanical analyses also indicated that, with the exception of one variable (planter flexion angle at toe-of), gait characteristics remained unaltered after the PMR. When considered from a cross-disciplinary perspective, these data suggest that a 30 min maximal run does not increase the aerobic demand of running or disrupt the running mechanics of moderately trained male subjects who perform subsequent submaximal runs over the short term.

93. Myles WS & Saunders PL (1979): The physiological cost of carrying light and heavy loads. Eur.J.Appl.Physiol 42, 125-131.

Nine subjects walked on a treadmill with load weights equal to 10% and 40% of body weight carried on the back. Although the speed of the treadmill was selected so that the measured oxygen consumption VO2 was the same for both load conditions, the heavier load placed an extra strain on the cardiopulmonary system and was perceived by all subjects as harder work than the lighter load. When the subjects worked at their own pace, walking on a level road or climbing stairs with load weights equal to 10% and 40% of body weight, they compensated for the heavier load by decreasing walking speed or climbing rate. Although the energy costs calculated from walking speed, body and load weight for self-paced walking and the external work of stair climbing were the same for both load conditions, the heavier load was again perceived as harder work. These findings are discussed as they relate to the definition of acceptable load weights.

94. Myo-Thein, Lammert O & Garby L (1985): Effect of trunk load on the energy expenditure of treadmill walking and ergometer cycling. Eur.J.Appl.Physiol 54, 122-124.

Data concerning the effect of trunk loads on the energy expenditure of various activities are scanty and partly conflicting. The energy expenditure of walking (4.5 km hr-1, 1.5% inclination) and ergometer cycling (60 watt, 60 rpm) was measured in 23 apparently healthy subjects with and without a trunk load of 10% of the body weight. For walking, the increment in energy expenditure per kg of load was 2.55 +/- 0.25 watt, while the increment per kg of body weight was 4.01 +/- 0.45 watt. For ergometer cycling, the increment per kg of load was 1.12 +/- 0.64 while that per kg of body weight was 2.73 +/- 0.56 watt. Prediction of energy expenditure for trunk loads has previously been made on the basis of the relation between energy expenditure and body weight. Our data show that this may lead to considerable overestimation.

95. Niinimaa V, Dyon M & Shephard RJ (1978): Performance and efficiency of intercollegiate cross-country skiers. Med.Sci.Sport Exerc. 10, 91-93.

Ten male intercollegiate cross-country skiers were studied to identify factors influencing competitive performance and to estimate the efficiency of energy expenditure in skiing. The variables examined were maximum oxygen intake, as determined by both uphill treadmill running and by maximal level skiing, physical characteristics, strength and experience in cross-country skiing and racing. Multiple regression analysis showed that racing experience, cardiorespiratory fitness, and body fat percentage were significant factors in racing success. The net mechanical efficiency at this level of competition was estimated at 21.3%.

96. O'Connell ER, Thomas PC, Cady LD & Karwasky RJ (1986): Energy costs of simulated stair climbing as a job-related task in fire fighting. J.Occup.Med. 28, 282-284.

The purpose of this investigation was to determine the energy requirement of simulated stair climbing. Metabolic costs of climbing stairs in getting to the scene of a fire can be very demanding for fire personnel. Heart rate and oxygen consumption were measured on 17 fire fighters during each of three conditions: (1) stair climbing without fire-fighting uniform or equipment, (2) stair climbing with fire-fighting uniform and equipment, and (3) pedaling a bicycle ergometer in a graded maximal exercise test. These three conditions were designed to determine (1) baseline reference values, (2) actual work task measures, and (3) maximum reference values. Results showed that climbing stairs with an 8-inch rise at 60 steps per minute with fire fighter's uniform and equipment (86.5 pounds) for five minutes required heart rates to reach 95% (84 to 100) of maximum effort, and oxygen consumption measures were found to be 80% (63 to 97) of maximum. It was concluded for the personnel studied that the rate of energy cost of climbing a simulated staircase with uniform and equipment required an ability to consume at least 2.7 L of oxygen per minute and 39 mL/kg/min.

97. Otman S. Basgoze O & Gokce-Kutsal Y (1988): Energy cost of walking with flat feet. Prosthet. Orthot. Int. 12, 73-76.

School of Physiotherapy and Rehabilitation, Hacettepe University, Ankara, Turkey. A comparative study has been conducted to assess the effects of arch support on oxygen consumption in 20 subjects with flat feet who were generally complaining about fatigue, and also to explore whether their feeling of weariness was objective or not. The resting, walking and final recovery heart rates, blood pressures, and walking oxygen consumption values of the patients with flat feet were measured and calculated and compared to a control group using treadmill and oxygen consumption devices. In stage one the patients did not wear any arch support. Then suitable arch supports were prepared for each patient and in stage two they wore these arch supports. The results did not show any significant difference between the resting heart rates, blood pressure and oxygen consumptions. However, differences in walking heart rate, systolic blood pressure, final recovery heart rate, oxygen consumption, and energy cost values were found to be significant between stage one and two of the test in the patient group. The difference in walking diastolic blood pressure values without and with arch support were found to be insignificant. It may therefore be deduced that oxygen consumption during walking is decreased when a suitable arch support is applied to patients with flat feet.

98. Pahud P. Ravussin E, Acheson KJ & Jequier E (1980): Energy expenditure during oxygen deficit of submaximal concentric and eccentric exercise. .J.Appl.Physiol 49, 16-21.

Aerobic (MR) and anaerobic (Man) energy production was determined in five subjects during the 1 st min of concentric and eccentric exercise (steady-state energy expenditure approximately 415 W in both situations). Man was obtained by solving the heat balance equation, MR + Man - S = (R + C + E) +/- parallel to W parallel to, all other variables of which could be measured [S is heat storage; (R + C + E) are the radiative, convective, and evaporative heat losses; and W is work output]. The size of the 02 deficit was similar whatever the type of exercise (99 +/- 19 W concentric and 102 +/- 19 W eccentric). MR + Man was lower than the steady-state MR in both types of exercise (concentric; 364 +/- 19 and 407 +/- 24 W. respectively, and eccentric; 346 +/25 and 430 +/- 21 W. respectively). The size of the 02 deficit during the 1 st min of muscular exercise is imposed by the steady-state energy requirement whatever the type of exercise. The smaller energy expenditure during this phase is probably due to less energy being released when creatine phosphate is split without resynthesis (02 deficit) than during splitting and resynthesis of high-energy phosphate bonds (steady state).

99. Pahud P. Ravussin E & Jequier E (1980): Energy expended during oxygen deficit period of submaximal exercise in man. .J.Appl.Physiol 48, 770-775.

Aerobic (MR) and anaerobic (Man) metabolism was determined during the transition from mild (SO W external work) to heavier exercise (50% VO2max in six subjects. The overall exercise efficiency was calculated during the oxygen deficit period and during steady-state exercise. MR was obtained by indirect calorimetry and Man by solving the heat balance equation: MR + Man S = (R + C + E) + W. where radiative, convective, and evaporative heat losses (R + C + E) were measured by direct calorimetry, work output (W) by ergometry, and heat storage (S) by thermometry. (MR + Man) during the oxygen deficit period was found to be lower than MR during steady state. In the 1 st min of exercise, mean mixed work efficiency (aerobic + anaerobic) was 33%, which was greater than aerobic efficiency (26.6%) during steady state. The mean anaerobic efficiency was 41%. This difference reflects the fact that the energy released by splitting of preformed high-energy bonds (i.e., creatine phosphate) is less than the energy released when high-energy bonds expended during mechanical work are continuously regenerated through oxidative phosphorylation. The reported measurements of overall energy metabolism in man provide means for estimating in vivo the coupling efficiency of physical work (i.e., 41%) as well as the efficiency with which energy released by substrate oxidations is recovered in the form of high-energy bonds (i.e., phosphorylation efficiency = 64%).

10. Pandolf KB, Kamon E & Noble BJ (1978): Perceived exertion and physiological responses during negative and positive work in climbing a laddermill. J.Sports Med. 18, 227-236.

Ratings of perceived exertion (RPE) were compared while fifteen highly fit male subjects climbed up (positive work) and down (negative work) a motor-driven ladder, and while stool-stepping. The ladder was inclined at 30 from the vertical with the climbing rates for both positive and negative work being 7.5, 10.5 and 14.5 m/mint These climbing rates were performed by all subjects for positive and negative work using either a foot-over-foot climb (regular climb) or while climbing both feet to each rung (stepping climb). When similar climbing methods were compared at equivalent climbing rates, the RPE like the oxygen uptake VO2 and heart rate HR) for positive work was greater than that for negative work. However, when negative work stepping climb was compared to positive work regular climb, the RPE did not differ significantly. It was hypothesized that feelings of strain and discomfort in the working muscle and joints during negative work stepping climb became a dominant factor in the setting of RPE. Although much less costly metabolically, negative work (stepping climb) was perceived to be equally stressful as positive work (regular climb). Although stool-stepping involves both a positive and negative work component for unidirectional climb at the same rate as ladder climbing, the RPE for stool stepping similar to the VO2 cost seems to summate both components rather than be an intermediate value.

101. Patton JF, Bidwell TE, Murphy MM, Mello RP & Harp ME (1995): Energy cost of wearing chemical protective clothing during progressive treadmill walking. Aviat.Space.Environ.Med. 66, 238-242.

Occupational Physiology Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA 01760, USA. While chemical protective (CP) clothing is known to adversely affect physical performance, few data exist regarding the physiological response of wearing US military CP clothing during incremental, dynamic exercise. To quantify the effects of CP clothing on energy cost and to test the hypothesis that the mask contributes little to this effect, oxygen uptake VO2 and ventilation (VE) were determined in 14 male soldiers who walked on a treadmill at 1.56 m.s-1 for 20 min each at 0, 5, and 10% grades in three clothing conditions: BDU (battledress uniform only), MASK (BDU + M-17 protective mask), and CP clothing (MASK + overgarment, gloves and boots). In BDU's, exercise intensities expressed as VO2max were 29, 42, and 59% at the three grades, respectively. VO2 was significantly (p < 0.01) greater at all grades (range 13 to 18%) in CP clothing compared to BDU. However, no differences in VO2 were seen between BDU and MASK at any level of exercise. VE was significantly higher at the two highest grades in CP clothing compared to BDU but when expressed relative to VO2 (VE/VO2) was significantly lower at 0% and 5% grades but not at 10%. In the MASK condition, VE was significantly lower at the 10% grade and VE/VO2 was significantly lower at all grades compared to BDU. The results show that despite the mask induced hypoventilation, VO2 is unaffected at exercise intensities up to 60% of VO2max We conclude that the contribution of the mask to the overall physiological strain of exercising in CP clothing is minimal at these exercise intensities and that the 13-18% increase in VO2 with CP clothing is attributable to its weight and hobbling effect.

102. Patton JF, Kaszuba J. Mello RP & Reynolds KL (1991): Physiological responses to prolonged treadmill walking with external loads. Eur.J.Appl.Physiol 63, 89-93.

Occupational Physiology Division, US Army Research Institute of Environmental Medicine, Natick, MA 01760-5007. Limited information is available regarding the physiological responses to prolonged load carriage. This study determined the energy cost of prolonged treadmill walking (fixed distance of 12 km) at speeds of 1.10 m.s-1, 1.35 m.s-1, and 1.60 m.s-1, unloaded (clothing mass 5.2 kg) and with external loads of 31.5 and 49.4 kg. Fifteen male subjects performed nine trials in random order over a 6-week period. Oxygen uptake (VO2) was determined at the end of the first 10 min and every 20 min thereafter. A 10-min rest period was allowed following each 50 min of walking. No changes occurred in VO2 over time in the unloaded condition at any speed. The 31.5 and 49.4 kg loads, however, produced significant increases (ranging from 10 to 18%) at the two fastest and at all three speeds, respectively, even at initial exercise intensities less than 30% VO2max. In addition, the 49.4 kg load elicited a significantly higher (P < 0.05) VO2 than did the 31.5 kg load at all speeds. The measured values of metabolic cost were also compared to those predicted using the formula of Pandolf et al. In trials where VO2 increased significantly over time, predicted values underestimated the actual metabolic cost during the final minute by 1016%. It is concluded that energy cost during prolonged load carriage is not constant but increases significantly over time even at low relative exercise intensities. It is further concluded that applying the prediction model, which estimates energy expenditure from short-term load carriage efforts to prolonged load carriage, can result in significant underestimations of the actual energy cost.

103. Peacock B (1980): The physical workload involved in parcel handling. Ergonomics, 23, 417424.

Sixteen subjects of varying age and anthropometric characteristics were each asked to perform a series of parcel handling activities at an 'habitual' rate for 2 h. Work rate and oxygen consumption were monitored for the various task components which were arranged to enable carry over effects to be investigated. The results indicated that an energy output of between 400 W and 500 W could be considered as being 'habitual' for this form of task. However in submaximal tasks of this nature anthropometric factors are likely to play a greater part in determining energy expenditure than age or work rate factors as work rate is largely influenced by the interaction between anthropometric characteristics and workplace design.

104. Pierrynowski MR, Winter DA & Norman RW (1981): Metabolic measures to ascertain the optimal load to be carried by man. Ergonomics, 24, 393-399.

As part of a combined electromyographic, mechanical work and metabolic study of load carriage this research focuses on the optimal load carried by the subject. This study demonstrates the anomalies associated with the definition of optimal workload, and shows that it is dependent on whether or not the carrier is given any credit for carrying his own weight as well as that of the load. In many situations it may be important to include the carrier's own body mass in the optimal load equation. This study showed that if the load were body plus backpack the optimal backpack load was found to be quite low (less than 10 kg) because the metabolic cost increased quite rapidly at low loads. On the other hand, if the carrier's mass was ignored there might be an optimum load at 40 kg or higher. Giving partial 'credit' for carrying body weight (for example, 50% body mass plus backpack), resulted in an optimum load of about 17 kg. The percentage 'credit' given to the body mass itself depends on how important it is that the carrier does not arrive fatigued at his destination. The military may wish to give 100% credit, and recreational carriers zero.

105. Pierson WR & Rich GD (1967): Energy expenditure and fatigue during simple repetitive tasks. Hum.Factors, 9, 563-566.

Twenty-five male college students were measured for oxygen consumption during a simple stimulus-response task. Performance, as measured by reaction time and speed of arm movement, maintained a steady state except for a period of work decrement which had no relationship to initial speed or isotonic decrement. Oxygen consumption was maintained at a steady state rate throughout the task. Fatigue, work decrement, and endurance were not reflected in oxygen consumption rates.

106. Pimental NA & Pandolf KB (1979): Energy expenditure while standing or walking slowly uphill or downhill with loads. Ergonomics, 22, 963-973.

Eight fit male subjects (24 yr, 176 cm, 79 kg) stood, or walked at speeds of 0.5 or 0.9 m.s^-1- for 20-min periods on grades of -10 to +25% with loads of 20 or 40 kg. Energy expenditure (watt) was not significantly different in any of the standing conditions: grade and load increased energy expenditure while standing but not significantly. Although all the energy expenditure means were relatively low, high perceived exertion ratings suggest limits to tolerance time in some of these conditions. All the standing means were significantly lower than the walking means. Walking 0.9 m.s^-1 on a 10% grade was significantly lower than walking 0.5 m.s^-1 on a 10% grade, which was significantly lower than walking 0.9 m.s^-1 on a +10% grade. In the walking conditions there was a significant difference between loads: means for the 20 kg loads were lower than means for the 40 kg loads. As the condition became more strenuous by increasing load, speed, and/or grade (while walking), energy expenditure became more sensitive to changes in these variables. The current energy expenditure prediction formula (Pandolf et a/. 1977) was found to predict slightly high for the standing conditions, low for walking 0.5 m.s^-1 on a 10% grade, and accurately for walking 0.9 m.s^-1 on a 10% grade. In the standing conditions the deviation between predicted and measured was higher at the 40 kg load than at the 20 kg load. The formula in its present form is not equipped to predict for negative grades. The results of this study suggest that the prediction formula may place too much emphasis on the effects of speed and load while standing and walking slowly.

107. Pimental Shapiro Y & Pandolf KB (1982): Comparison of uphill and downhill walking and concentric and eccentric cycling. Ergonomics, 25, 373-380.

Seven male subjects (20 years, 1,'6 cm, 70 kg, 16% body fat) walked on a treadmill at various grades (-15 to +30%) and speeds (up to 1.56 m.s^-1 carrying loads up to 30 kg. They also performed concentric and eccentric cycling at exercise intensities (El) ranging from 0 to 260 W (~1600 kpm.min^-1). Exercise bouts lasted 20 min. At the same oxygen consumption, eccentric cycling elicited the highest heart rate, followed by downhill walking, uphill walking and concentric cycling. Only the regression line for eccentric cycling had a significantly higher slope than the other three regression lines (p<0.05). Average gross exercise efficiencies for uphill walking and concentric cycling were similar (13.5 and 14.5%) and were significantly different from those for downhill walking (-33.5%) and eccentric cycling (-60.6%). For each type of exercise, absolute efficiency was greater with increasing El. Actual energy expenditures for walking uphill and on the level were then compared to predicted values using the formula of Pandolf et a/. (1977). The formula was found to be accurate for all uphill conditions at 1.12 m.s^-1 For walking uphill at 0.56 m.s^-1 the formula predicted slightly low (5-16%) while the formula underestimated energy expenditure for level walking by 14-33%. These findings would imply further modifications to this formula are necessary, particularly to include the observations for downhill walking.

108. Pugh LG (1970): Oxygen intake in track and treadmill running with observations on the effect of air resistance. J.Physiol. 207, 823-835.

1. The relation of VO2 and speed was measured on seven athletes running on a cinder track and an all-weather track. The results were compared with similar observations on four athletes running on a treadmill. 2. In treadmill running the relation was linear and the zero intercept coincided with resting VO2 3. In track running the relation was curvilinear, but was adequately represented by a linear regression over a range of speeds extending from 8.0 km/hr (2.2 m/see) to 21.5 km/hr (6.0 m/sec). The slope of this line was substantially steeper than the regression line slope for treadmill running. 4. The influence of air resistance in running was estimated from measurements of VO2 on a subject running on a treadmill at constant speed against wind of varying velocity. 5. The extra 02 intake (delta VO2 associated with wind increased as the square of wind velocity. If wind velocity and running velocity are equal, as in running on a track in calm air, delta VO2 will increase as the cube of velocity. 6. It was estimated that the energy cost of overcoming air resistance in track running is about 8% of total energy cost at 21.5 km/hr (5000 m races) and 16% for sprinting 100 m in 10.0 sec.

109. Pugh LG (1974): The relation of oxygen intake and speed in competition cycling and comparative observations on the bicycle ergometer. J.Physiol. 241, 795-808.

1. The relation of VO2 and speed was determined on six competition cyclists riding at speeds ranging from 12 km/hr to 41 km/hr on the bicycle ergometer to determine the corresponding work rates and from this information rolling resistance and air resistance were derived. 2. VO2 was a curvilinear function of cycling speed, and increased from 0.88 I/min at 12.5 km/hr to 5.12 I/min at 41 km/hr, mean body weight being 72.9 kg. 3. On the ergometer, VO2 was a linear function of work rate; maximum values up to 5.1 I/min (74.4 ml/kg.min) and work rates up to 425 W (2600 kg m/min) were observed. 4. Data are presented on the relation of pedal frequency and speed in cycling, and on the relation of mechanical efficiency and pedal frequency, as determined on the ergometer. 5. The estimated rolling resistance for four subjects was 0.71 kg f. The drag coefficient was 0.79 and the drag area 0.33 m². The values agreed well with results obtained by other methods. 6. The energy expenditure (power developed) in cycling increased approximately as the square of the! speed, and not as the cube of the speed as expected. This was explained by the varying contribution of rolling resistance and air resistance to over-all resistance to motion at different speeds.

110. Pugh LGCE (1971): The influence of wind resistance in running and walking and the mechanical efficiency of work against horizontal or vertical forces. J.Physiol. 213, 255-276.

1. O intakes were determined on subjects running and walking at various constant speeds, (a) against wind of up to 18.5 m/see (37 knots) in velocity, and (b) on gradients ranging from 2 to 8%. 2. In running and walking against wind, 02 intakes increased as the square of wind velocity. 3. In running on gradients the relation of 02 intake and lifting work was linear and independent of speed. In walking on gradients the relation was linear and independent of speed. In walking on gradients the relation was linear at work above 300 kg m/min, but curvilinear at lower work rates. 4. In a 65 kg athlete running at 4.45 m/see (marathon speed) VO2 increased from 3.0 I/min with maximal wind to 5.0 I/min at a wind velocity of 18.5 m/sec. The corresponding values for a 75 kg subject walking at 1.25 m/see were 0.8 I/min with minimal wind and 3.1 I/min at a wind velocity of 18.5 m/sec. 5. Direct measurements of wind pressure on shapes of similar area to one of the subjects yielded higher values than those predicted from the relation of wind velocity and lifting work at equal 02 intakes. Horizontal work against wind was more efficient than vertical work against gravity. 6. The energy cost of overcoming air resistance in track running may be 7.5% of the total energy cost of middle distance speed and 13% at sprint speed. Running 1 m behind another runner virtually eliminated air resistance and reduced VO2 by 6.5% at middle distance speed.

111. Richerson RL & Richerson ME (1981): Energy expenditure in simulated tasks: comparison between subjects with brain injury and able-bodied persons. Arch.Phys.Med.Rehabil. 62, 212214.

Energy expenditure of 7 brain-injured individuals was compared to that of 10 able-bodied individuals. Data were collected with the subjects at rest and while performing 4 simulated industrial tasks: material handling, crank rotation, electric switch operation, mechanical assembly. Energy expenditure was determined by measuring oxygen consumption VO2 Energy usage per unit weight per unit time was calculated for each subject. Over the range of tasks, the brain injured means varied from 0.0396 to 0.0674 kcal/kg/min, while the able-bodied means were between 0.0413 and 0.0849 kcal/kg/min. The cranking task showed the only statistically significant difference for this measure. Total energy use/unit weight was also examined, the brain injured group averaging more energy use during the material handling, switching, and assembly tasks and the able-bodied group averaging more energy use on the cranking task. Two factors explaining these results appear to be motivation and complexity of hand movements for each task. The performance of the brain injured group on the cranking task indicates ways of adapting crank operated control mechanisms for use by the handicapped.

112. Riggs CEJ, Johnson DJ, Kilgour RD & Konopka BJ (1983): Metabolic effects of facial cooling in exercise. Aviat.Space Environ.Med. 54, 22-26.

Metabolic responses to facial cooling during prolonged exercise were investigated in five male subjects. Exercise on a bicycle ergometer at 50 rpm for 1 h at 60% maximal heart rate was performed twice, once with cold wind (10 ° C, 6.5 m.s-1) and once without. Resting experiments were conducted under identical conditions. Facial cooling apparently had no effect on plasma FFA or glucose concentration during exercise but did, however, result in significantly (p < 0.05) greater fat utilization, as indicated by lower respiratory exchange ratios at 60 min of exercise. The respiratory exchange ratio, blood lactate concentration, oxygen consumption, and estimated myocardial oxygen consumption at 5 min of exercise were higher with facial cooling. The results suggest that metabolic changes occur with facial cooling that are related to a general thermoregulatory response and that the stress of exercise is greater with facial cooling.

113. Seabury JJ, Adams WC & Ramey MR (1977): Influence of pedalling rate and power output on energy expenditure during bicycle ergometry. Ergonomics, 20, 491-498.

After review of previous studies, it seemed desirable to investigate further the interrelationships between pedalling rate, power output, and energy expenditure, using bicycle ergometry as a model for recreational bicycling. Three young adult male subjects rode a Monark ergometer at eight pedalling rates (30-120 rev. min^-1 and four power outputs ('0', 81.7, 163,4 and 196.1 W). VO2 determinations were made and using measured R. gross energy expenditure was derived. When these values were combined with results of other researchers using similar protocol but different power outputs, it was found that: (1) a 'most efficient' pedalling rate exists for each power output studied: (2) the 'most efficient' pedalling rate increases with power output from 42 rev.min-1 at 40.8W to 62 rev.min^-1 at 326.8 W: and (3) the increase in energy expenditure observed when pedalling slower than 'most effcient' is more pronounced at high power outputs than at low output, while the increase in reponse to pedalling faster than 'most efficient' is less pronounced at high power outputs than at low outputs. Thus, there is appreciable interaction between pedalling rate and power output in achieving the most efficient rate in bicycle ergometry. The most efficient pedalling rate observed at high power outputs in the present study is considerably lower than that reported for racing cyclists by others. This discrepancy may well be related to the difference in swing weights between the ergometer's heavy steel flywheel and crankset, and that of the lightweight wheel and crankset used on racing bicycles.

114. Seliger V (1968): Energy metabolism in selected physical exercises. Int.Z.angew.Physiol. einschl. Arbeitsphysiol. 25, 104-120.

The energy costs of 15 physical activities were examined in 275 subjects under training conditions of the particular activity. The sample contains usually 15 medium athletically developed persons at minimum. The energy metabolism was followed by indirect calorimetrical method, the heart rate was registered throughout the experimental telemetrically. The activities were divided into three groups, according to the time of duration. The results showed that the energy expenditure ranges were in A-group (duration 5 min and more) 0.08-0.26 kcal/min/kg, in B-group (1-3 min) 0.11-0.45 kcal/min/kg, and in C-group (1-30 see) 0.68-1.75 kcal per min/kg. The observed values of heart rate, pulmonary ventilation, and oxygen uptake are discussed. No correlation between the energy expenditure and the intensity of the motional activity, according to pedagogues observation was found. The relationship to physiological function was with respect to motional activity on 1-5% significance level, especially in sports from groups A and B. A graph was constructed of the relationship of the intensity of metabolism, against duration of the activity. Three fields limited by parallel lines enables us to judge the real metabolic rate during the sports activity of examined persons to functional development of his organismus.

115. Sengupta AK, Sarkar DN, Mukhopadhyay S & Goswami DC (1979): Relationship between pulse rate and energy expenditure during graded work at different temperatures. Ergonomics, 22, 1207-1215.

Pulse rate and energy expenditure were measured on fifteen male subjects who had been given ergometer cycling of 'O' and 32.6W to 97.8W in three temperatures of 22°C, 30°C, and 37°C. The variation in pulse rate of each graded work period was compared with the variation in energy expenditure for each environmental temperature. The-pulse rate was significantly increased with the rise of environmental temperature (p<0.01) whereas the energy expenditure (kJ.min^-1) was consistently or effectively decreased with higher graded work. However, a correlation was obtained between the pulse rate and energy expenditure during graded work up to a limit of 150 beats.min-1, 160 beats.min^-1, and 170 beats.min^-1 in temperatures of 22°C, 30°C and 37°C respectively. The results were analyzed by computing the analysis of variance and regression equation evaluated for each temperature, indicating that independent regression lines having two components, one above 95 and another below 95 beats.min^-1, were required in each set of temperature. The percentage error between observed and predicted values (pooled) of energy expenditure for the two ranges of pulse rate varied from 0.3 to 11.5 and from 0.5 to 9.5 respectively in the three temperatures.

116. Sidossis LS, Horowitz JF & Coyle EF (1992): Load and velocity of contraction influence gross and delta mechanical efficiency. Int.J.Sports Med. 13, 407-411.

Department of Kinesiology and Health, University of Texas, Austin 78712. The effects of three different cadences and five different work rates on Gross (GE) and Delta Efficiency (DE) during cycle ergometry were studied. Fifteen well-trained cyclists exercised for 30 minutes at 60, 80, or 100 RPM on three different occasions. On each occasion, the load was increased every five minutes and corresponded to approximately 50, 60, 70, 80 and 90% of VO2max During the last three minutes of each stage, steady-state energy expenditure was calculated while work rate was recorded. In addition, the oxygen cost of unloaded cycling (CUC) was also measured. GE was calculated as the ratio of work rate to the rate of energy expenditure, whereas DE was calculated as the reciprocal of the slope of this relationship at work rates between 50 and 90% of VO2max The CUC corresponded to 0.66 +/-0.03 I/min, 0.77 +/- 0.04 I/min and 1.04 +/- 0.04 I/min at 60 RPM, 80 RPM and 100 RPM, respectively (p c 0.01 for all comparisons). GE was similar at all cadences when cycling at 80 and 90% VO2max DE increased with increasing rpm and corresponded to 20.6 +/- 0.4%, 21.8 +/- 0.6%, and 23.8 +/- 0.4% at 60 RPM, 80 RPM and 100 RPM, respectively (p < 0.01 for all comparisons). Therefore, when trained cyclists exercise intensely (80-90% VO2max GE is similar at cadences of 60, 80 and 100 RPM, despite the significant increase in the CUC. Thus, it is possible that delta efficiency increases with increasing cadence.

117. Soule RG & Goldman RF (1969): Energy cost of loads carried on the head, hands, or feet. .J.Appl.Physiol 27, 687-690.

Ten subjects (22 yr, 174 cm, 70 kg) walked for 20 min on a treadmill at 4.0, 4.8, or 5.6 km/hr carrying: 1) no load, 2) 4 kg, or 3) 7 kg on each hand, 4) 6 kg on each foot, or 5) 14 kg on the head. Loads 3, 4, and 5 represented a maximum for these subjects. Energy cost, expressed as milliliters of 02 per minute per kilogram of total weight (man + clothing + load), agreed, for the no load condition, with our previous studies. The cost per kilogram of weight carried on the head was 1.2 times the expected cost per kilogram of the no load condition at all speeds. At 5.6 km/hr, the cost per kilogram of load carried on the hands was 1.9 times the no load cost for both the 4 and 7-kg loads; at the slower speeds the cost for the 7-kg load was also 1.9 times the no load cost. However, the 4-kg load cost per kilogram was only 1.4 times, presumably reflecting compensations at the lower load and speeds. The cost per kilogram of load carried on the feet was 4.2 times the load cost per kilogram at 4.0 km/hr, 5.8 times at 4.8 km/hr, and 6.3 times at 5.6 km/hr. Since, in this study, the order of presentation was varied to eliminate training effects, it is impossible to estimate the extent to which these extra costs might be reduced by training; however, considering the mechanical leverages, some extra costs must always be incurred.

118. Soule RG, Pandolf KB & Goldman RF (1978): Energy expenditure of heavy load carriage. Ergonomics, 21, 373-381.

Fourteen subjects (22yr, 175 cm, 72 kg) walked for 20 min on a treadmill at 3.2, 4.8 or 6.4 km.h 1 carrying 35, 40, 45 or 50 kg; during a second phase, ten additional subjects (22 yr, 178 cm, 75 kg) attempted to walk for 45 min at the same speeds carrying 60, 65, or 70 kg. Energy expenditure when expressed as cm³ oxygen per minute per kilogramme of total weight (man+clothing+load) agreed, for the no load condition, with literature values. After deducting the individuals no load cost, the resulting net energy expenditure for carrying the loads, when expressed as cm³kg^-1min^-1 was generally constant at each speed; i.e. Ioads from 35 to 70 kg showed no statistical differences in energy expenditure per kilogramme at 3.2 and 4.8 km h^-1. At 6.4 km h^-1 carrying 70 kg, the average measured cost per kg was statistically different (p<0.05) than carrying 35 kg at this speed; subjects were working at greater than 90% of their maximal VO2 levels carrying 70 kg. However, similar comparison of the measured cost per kg between loads of 40 and 65 kg was statistically the same at 6.4 km h^-1. The general constancy of measured energy expenditure per kg for loads even up to 70 kg, probably depends on the condition that the load is well balanced and close to the centre of the body. As reported earlier, higher costs are associated with loads in unbalanced positions. Thus, the limitations commonly encountered in load carrying capacity may arise from poor positioning of the load rather than from the weight of the load per se.

119. Spurr GB & Reina JC (1986): Marginal malnutrition in school-aged Colombian boys: body size and energy costs of walking and light load carrying. Hum.Nutr.Clin.Nutr. 40C, 409-419.

The energy expenditure of 93 Colombian boys aged 6-16 years of age and 10 adult American males was measured while walking on a treadmill at 3 mph and 0, 4, 8 and 12 per cent grades with and without backpack loads of 3 (6-8 year), 6 (10-12 year) and 9 kg (14-16 year and adults). The boys were also divided into nutritionally normal and marginally malnourished, based on their weight-for-age and weight-for-height. The primary dependence of energy expenditure on body weight or body weight plus load was not affected by nutritional status, and the results of both adults and control and malnourised children fell on the same straight line at a given treadmill grade, indicating that the undernourished subjects would expend the same energy as nutritionally normal boys and adult subjects for a given load carried. The undernourished boys worked at a higher percentage VO2max than control subjects when load carrying.

120. Staab JS, Agnew JW & Siconolfi SF (1992): Metabolic and performance responses to uphill and downhill running in distance runners. Med.Sci.Sport Exerc. 24, 124-127.

Department of Movement Science, Springfield College, MA 01109. Distance running performance is slower on hilly race courses than flat courses even when the start and finish are at the same elevation, resulting in equal amounts of uphill and downhill running. The physiological mechanism limiting performance on these courses is not known. We examined the effects of uphills and downhills with 11 trained male distance runners running three 30 min self-paced competitive races on a treadmill. Race courses consisted of five, 6 min stages. Percent grades were: course A (0, 0, 0, 0, 0), course B (0, +5, 0, -5, 0) and course C (0, -5, 0, +5, 0). Pace, oxygen consumption VO2 heart rate (HR), blood lactate (LA), and rating of perceived exertion (RPE) did not change significantly (P > 0.05) over stages on the control course A. Pace changed inversely with percent grade on courses B and C. The increase in downhill running pace was inadequate to maintain a level VO2 during the race. LA increased on the uphill stages even though running pace decreased. The running paces for courses B and C were slower (P c 0.05) than course A by 2.8% and ,2.4%, respectively. Runners do not maintain constant energy expenditure when racing on hilly courses. Lactate accumulated on uphill stages even though pace decreased. Running pace increased on downhills but not enough to maintain a constant VO2

121. Starling RD, Costill DL, Trappe TA, Jozsi AC, Trappe SW & Goodpaster BH (1995): Effect of swimming suit design on the energy demands of swimming. Med.Sci.Sport Exerc. 27, 1086-1089.

Human Performance Laboratory, Ball State University, Muncie, IN 47306, USA. Eight competitive male swimmers completed a standardized 365.8 m (400 yd) freestyle swimming trial at a fixed pace (approximately 90% of maximal effort) while wearing a torso swim suit (TOR) or a standard racing suit (STD). Oxygen uptake VO2 blood lactate, heart rate (HR), and distance per stroke (DPS) measurements were obtained. In addition, a video-computer system was used to collect velocity data during a prone underwater glide following a maximal leg push-off from the side of the pool while wearing the TOR and STD suits. These data were used to calculate the total distance covered during the glides. VO2 (3.76 +/- 0.16 vs 3.92 +/0.18 I.min-1) and lactate (8.08 +/-0.53 vs. 9.66 +/- 0.66 mM) were significantly (P < 0.05) lower during the TOR trial than the STD trial. HR was not different (P > 0.05) between the TOR (170.1 +/- 5.1 b.min-1) and STD (173.5 +/-5.7 b.min-1) trials. DPS was significantly greater during the TOR (2.70 +/- 0.066 m.stroke-1) versus STD (2.58 +/- 0.054 m.stroke-1) trial. A significantly greater total distance was covered during the prone glide while wearing the TOR (2.05 +/- 0.067 m) compared to the STD (2.00 +/- 0.080 m) suit. These findings demonstrate that a specially designed torso suit reduces the energy demand of swimming compared to a standard racing suit which may be due to a reduction in body drag.

122. Steinacker JM, Marx TR, Marx U & Lormes W (1986): Oxygen consumption and metabolic strain in rowing ergometer exercise. Eur.J.Appl.Physiol 55, 240-247.

Oxygen consumption (VO2) when rowing was determined on a mechanically braked rowing ergometer (RE) with an electronic measuring device. VO2 was measured by an open spirometric system. The pneumotachograph valve was fixed to the sliding seat, thus reducing movement artefacts. A multi-stage test was performed, beginning with a work load of 150 W and increasing by 50 W every 2 minutes up to exhaustion. Serum lactate concentrations were determined in a 30 s break between the work stages. 61 examinations of oarsmen performing at maximum power of 5 W.kg-1 or more were analysed VO2 and heart rate (HR) for each working stage were measured and the regression line of VO2 on the work load (P) and an estimation error (Sxy) were calculated: VO2 = 12.5 . P + 415.2 (ml.min-1) (Sxy = +/- 337 ml, r = 0.98) Good reproducibility was found in repeated examinations. Similar spiroergometry was carried out on a bicycle ergometer (BE) with 10 well trained rowers and 6 trained cyclists. VO2 of rowing was about 600 ml.min-1 higher than for bicycling in the submaximal stages for both groups. The VO2max of RE exercise was 2.6% higher than for oarsmen on BE, and the cyclists reached a greater VO2 on BE than the oarsmen. No differences were found between RE and BE exercise heart rate. The net work efficiency when rowing was 19% for both groups, experienced and inexperienced: when cycling it was 25% for cyclists and 23% for oarsmen.

123. Strickland SS & Ulijaszek SJ (1990): Energetic cost of standard activities in Gurkha and British soldiers. Ann.Hum.Biol. 17, 133-144.

Department of Public Health and Policy, London School of Hygiene and Tropical Medicine, UK. Measurements of basal metabolic rate and energy expenditure at lying, sitting, standing, and performing a step test at four levels of exercise, were made on Gurkha soldiers stationed in Britain and on British controls matched by body weight and occupational background. There was no significant difference in basal metabolic rate (BMR), nor in the energy cost of lying, sitting and standing between the two groups. Gurkhas showed significantly lower gross and net energy expenditure, and so significantly greater net mechanical efficiency, at the lower levels of step exercise. The ratio of gross energy expenditure to BMR was lower in Gurkhas at the lowest rates of stepping compared with the British controls. These results suggest that the energy cost of some physical activities expressed as multiples of BMR may not be constant across populations.

124. Strydom NB, van graan CH, Morrison JF, Viljoen JH & Heyns AJ (1968): The influence of boot weight on the energy expenditure of men walking on a treadmill and climbing steps. Int.Z.angew.Physiol.einschl.Arbeitsphysiol. 25, 191-197.

Two subjects walked on a motor driven treadmill at 3 m.p.h. or stepped on and off a one foot high wooden block at 12 and 24 steps/min while wearing boots weighing either 4.08, 4.41, 5.62 or 6.50 lb per pair. The energy cost of each task was determined by measuring and analysing the expired air and calculating the amount of oxygen taken up in the lungs. Heart rates were also recorded during the stepping tests and all the data were statistically analysed. When subjects walked at 3 m.p.h. or climbed steps at a rate of 12 steps/min no significant increase in oxygen intake was observed when boot weight increased. Even the additional weight of leg guards had no marked influence on the energy expenditure at these two work intensities. Significant differences in oxygen intake did occur when the subjects stepped up and down at 24 steps/min, but the highest oxygen intake did not occur when the heaviest boots were worn by either subject. Provided that the weight of mine boots is kept within the limits of 4 to 6 lb per pair, there is no question of any loss in efficiency due to fatigue caused by boot weight.

125. Teitlebaum A & Goldman RF (1972): Increased energy cost with multiple clothing layers. J.Appl.Physiol. 32, 743-744.

The question of any increase in energy cost for walking with multiple clothing layers, apart from that increase as a result of added weight per se, was investigated with a seven-layer experimental clothing system. Eight subjects wearing a standard T-shirt and shorts and fatigue uniform and combat boots (T-shirt and fatigue shirt = 2 layers) walked in randomized sequence on treadmills at 5.6 or 8.0 km/hr either wearing an additional five layers of clothing over the fatigues or carrying the 11.19-kg weight of these layers as a lead-filled belt. Three 2-min respiratory samples were taken during each 20-min trial, at the 6-8, 12-14, and 18-20th min. A mean value of 514 +- 12.4 (se) W at 5.6 km/hr was obtained for the multiple-layer clothing system in contrast to 435 +- 12.9 W for the equivalent added weight carried at the same speed. At 8.0 km/hr the cost for the multiple-layer clothing system was 995 +- 32.3 W compared with 873 +- 24.9 W for the equivalent weight carried on the belt. These differences were very highly significantly different (P<0.001), with each individual expending more energy walking with the multiple layer system than with the equivalent weight carried as a belt.

126. Thomas TR, Feiock CW & Araujo J (1989): Metabolic responses associated with four modes of prolonged exercise. J.Sports Med.Phys.Fitness, 29, 77-82.

The purpose of this study was to compare energy expenditure and substrate utilization during 60 min of steady state-exercise at similar heart rates (HR) using four exercise modes: stationary cycle (C), rower (R), ski simulator (S), and treadmill (walking) (T). Five subjects (mean age = 23 +/ 4 yr) performed 60 min of continuous exercise at 65% HR max on each of the four modes in random order. Total energy (TE) and fat energy (FE) expenditure were determined from VO2 and respiratory exchange ratio (RER). VO2 during exercise averaged 2.427 for C, 2.167 for R. 2.242 for S. and 2.4201 min-1 for T and were not significantly different by repeated measures ANOVO (p > 0.05). RER, TE, and FE also were not statistically different among exercise modes. However, walking and skiing tended to use more fat; the average 60 min cumulative exercise values were 960 for C, 871 for R. 1088 for S. and 1188 kJ for T. The rate of fat expenditure generally increased after 20 min on all modes. These results indicate that the energy expended at comparable relative HR's is similar for four aerobic exercise modes.

127. Thomas TR & Londeree BR (1989): Energy cost during prolonged walking vs jogging exercise. Physician Sportsmed. 17, 93-102.

The calories expended and the substrates used by walking vs jogging were compared in nine young men who walked and jogged at 65% maximum heart rate (HRmax) (about 125 beats.min-1 ') for 60 minutes and 75% HRmax (about 145 beats.min-1) for 45 minutes. Jogging utilized more total energy and more fat energy than walking at both intensities. In addition, the men perceived jogging to be less strenuous, and oxygen pulse, an indicator of cardiovascular efficiency, was higher during jogging than walking. Recovery energy use was greatest after jogging at 75% HR max.

128. Thomson JM & Garvie KJ (1981): A laboratory method for determination of anaerobic energy expenditure during sprinting Can.J.Appl.Sport Sci. 6, 21-26.

Highly trained sprinters, marathon runners and untrained male control subjects were studied during treadmill sprinting. After confirming a workload which elicited exhaustion in just over a minute (mean time to exh. = 64.6 +/- 2.5 sec.), each subject performed sprints of 15, 30, 45 and 60 seconds duration in order that their energy expenditure could be segmented per 15-sec. of sprinting time. During every sprint, 02 consumption was recorded by closed-circuit spirometry. Following each sprint, serial 30-sec. venous blood samples were drawn in order to determine the peak lactate concentration. Energy expenditure was therefore determined as follows: i) aerobic energy from increments in 02 uptake, expressed in Kcal; ii) lactacid energy from increments in peak lactate, with the difference between peaks utilized to calculate the anaerobic glycolytic contribution to that 15-sec. segment, expressed in Kcal according to Margaria; iii) alactacid energy, expended over the initial 15-sec. segments, from the difference between the total energy requirement per 15-sec. less the measured aerobic plus the lactacid contributions. The sprinters expended the greatest (p < .05) anaerobic energy (46.2 +/- 5.1 Kcal) when compared to either the marathoners (31.6 +/- 5.7 Kcal) or controls (33.0 +/- 1.6 Kcal). The athletic groups demonstrated superior alactacid energy (sprinters = 21.4 +/- 4.4 Kcal; marathoners = 15.8 +/2.3 Kcal), both expending a substantial amount of energy from this source (20%) past 30-sec. In contrast, over the initial 30-sec. of sprinting, the control subjects had depleted their alactacid energy (12.2 +/- 3.3 Kcal). Only minor differences were observed in aerobic energy expenditure between the three subject groups throughout the sprint to exhaustion.

129. Thorstensson A (1986): Effects of moderate external loading on the aerobic demand of submaximal running in men and 1() year-old boys. Eur.J.Appl.Physiol 55, 569-574.

The effects of moderate external loading on the aerobic demand of submaximal running were studied in habitually active adult men (29-37 yrs) and 10 year-old boys. The load was symmetrically placed around the trunk and adjusted to correspond to 10% of body weight. Running was performed on a treadmill at 8, 10 and 11 km.h-1 (2.2, 2.8 and 3.1 m.s-1). A small, but consistent decrease in net oxygen uptake (gross oxygen uptake in ml.kg-1.min-1 minus calculated basal metabolic rate) with load was observed in both groups at all speeds, except for the men at 8 km.h-1. The decrease was larger for the boys and tended to enhance with speed. The boys had a higher net oxygen uptake than the adults at all unladen running velocities, whereas the difference in the loaded condition was significant only at the highest speed. The decrease in net oxygen uptake with load could not be directly correlated with differences in body weight or step frequency. It is hypothesized that a difference in the utilization of muscle elastic energy could underlie part of the age and load dependent changes observed in running economy.

130. Valencia ME, McNeill G. Brockway JM & Smith JS (1992): The effect of environmental temperature and humidity on 24 h energy expenditure in men. Br.J.Nutr. 68, 319-327.

Rowett Research Institute, Bucksburn, Aberdeen. The effects of environmental temperature and humidity and their interaction on 24 h energy expenditure were measured using whole-body indirect calorimetry in eight normal-weight young men who wore standardized light clothing and followed a controlled activity regimen. A randomized-block experimental design was used, with temperature effects assessed by measurements at 20, 23, 26 and 30 degrees, while humidity was altered from ambient (50-65% relative humidity) to high (80-93% relative humidity) at 20 and 30 degrees only. There was no significant effect of humidity on 24 h energy expenditure at the two extreme temperatures in this range, though when periods of sleep and exercise were excluded the energy expenditure at high humidity was significantly higher than that ambient humidity (P< 0.02). The effect of temperature at ambient humidity levels showed lower values at 23 and 26 degrees than at 20 and 30 degrees (P < 0.02). The effect of temperature was not equally apparent in all components of the 24 h energy expenditure, as sleeping metabolic rate and the energy cost of walking and cycling showed no significant effect of temperature over this range. This raises the possibility that the effects of temperature are attributable to behavioural changes during the waking portion of the day rather than any non-shivering thermogenic mechanisms at tissue level.

131. Van der Walt WH & Wyndham CH (1973): An equation for prediction of energy expenditure of walking and running. .J.Appl.Physiol 34, 559-563.

Oxygen consumptions and stride frequencies were measured on six subjects (62.8-102.1 kg) at each of the speeds of walking (3.2, 4.8, 6.4, and 8.0 km/hr) and running (9.7, 11.3, and 12,9 km/hr) on a level treadmill. Measurements of leg length were also made and pace lengths were calculated from the stride frequencies. Correlations of 0.85-0.99 between body weight and oxygen consumption were highly significant at all the speeds of walking and running. A partial correlation of 0.62 between VO2 (oxygen consumption) and the subjects' natural mean pace lengths during running, independent of M, MV², and length, was found (where M = mass; V = speed). The corresponding correlation between VO2 and leg length for this type of exercise, independent of M, MV², and pace length, was -0.72. These correlations are significant at the 1 % level. The correspondential correlations for walking were not significant at the 5% level. Pace length and leg length account for only 2% of the total variance in VO2 during running and are therefore not important variables in the prediction of energy cost. General equations which predict the oxygen cost of walking and running from M and MV² are developed. Correlation between the predicted and measured energy cost was 0.97 for walking and 0.98 for running, respectively.

132. van Ingen Schenau GJ, de Groot G & Hollander AP (1983): Some technical, physiological and anthropometrical aspects of speed skating. Eur.J.Appl.Physiol 50, 343-354.

Five elite speed skaters and fourteen well trained skaters of a lower performance level performed three maximal tests: a 3,000 m race from which the skating position and the stroke frequency were derived, an oxygen consumption test both during skating and during a bicycle ergometer test. From all subjects anthropometric measures were taken. The elite group showed a VO2 during cycling of 64.4 +/- 3.5 ml.kg-1.min-1 and 59.4 +/- 3.7 ml.kg-1.min-1 during skating. The elite skaters showed: a shorter upper leg length with respect to total leg length, higher aerobic power during cycling, higher stroke frequency, smaller pre-extension knee angle coupled to higher work per stroke, higher "efficiency" during skating and higher external power during skating and during cycling when compared with the group of lower performance level. It is concluded that an important pre-requisite for speed skating appears to be the possibility to skate at a small pre-extension knee angle without an excessive claim to anaerobic metabolism.

133. Venkataramana Y. Rao MS, Rao SS & Satyanarayana K (1995): Energy cost of graded work loads & mechanical effciency of sportsmen. Indian J.Med.Res. 101, 120-124.

Department of Physiology, National Institute of Nutrition, Hyderabad. This study was undertaken to determine oxygen consumption at rest and constant graded work loads while exercising on a bicycle ergometer and to compute mechanical effciency of sportsmen. Thirteen healthy, active, well trained young sportsmen from sports hostel, Sports Authority of India, Hyderabad, were selected and were requested to pedal the bicycle ergometer at 50 watts and 100 watts (300 and 600 kpm) work loads for 18-20 min. The energy cost of the activity at the respective work loads was measured by means of indirect, open circuit respiratory exchange method. The workouts resulted in the oxygen consumption of about 920.4 +/- 77.5 ml and 1475.2 +/- 101.7 ml at 300 and 600 kpm respectively. The gross mechanical efficiency (AME) were calculated at these work loads. The delta mechanical efficiency (DME) was also computed for the work increment from 300 to 600 kpm by using the amount of oxygen consumed at these work loads. The AME was about 23-24 per cent in both the loads while the DME was found to be 26 per cent. The relationship between anthropometry, resting metabolic rate (RMR),AME and DME was assessed. It was observed that both AME and DME values of these subjects were in the normal range of Swedish and Canadian active young men. These parameters can be used as indicators for assessing sports persons efficiency both in the active and lean periods.

134. Verma SS, Malhotra MS & Sen Gupta J (1979): Indirect assessment of energy expenditure at different work rates. Ergonomics, 22, 1039-1044.

Indirect measurement of energy expenditure during work is carried out from either minute ventilation or heart rate during the activity under consideration. In the present study a multiple linear regression equation has been evolved for estimating energy expenditure from minute ventilation and heart rate during various grades of submaximal work on a bicycle ergometer on 55 human subjects involving 165 observations. The product-moment correlations of minute ventilation and heart rate with energy expenditure were found to be 0.74 and 0.59 respectively. The multiple correlation coefficient between observed energy expenditure and both minute ventilation and heart rate was 0.80 (p<0.001). This is significantly (p<0.05) greater than the individual correlation coefficient for energy expenditure and minute ventilation alone. It is concluded that a combination of minute ventilation and heart rate is a better predictor of energy expenditure than either of the two variables used singly. A nonogram has been constructed for this purpose.

135. Vokac Z. Bell H. Bautz-Holter E & Rodahl K (1975): Oxygen uptake/heart rate relationship in leg and arm exercise, sitting and standing. .J.Appl.Physiol 39, 54-59.

The effect of leg exercise and of arm exercise in sitting and standing body positions on energy output and on some cardiorespiratory parameters was studied in seven male subjects. Oxygen uptake VO2 heart rate (fH), pulmonary ventilation (VE) and respiratory frequency were measured at rest, in the 7-8th min of submaximal work (300, 600, 900 kpm/min), and at maximal effort. Significantly higher Vo2, fH, and VE in arm cranking than in cycling were found at submaximal work loads above 300 kpm/min. Though the maximal work load in arm exercise was 50-60% of that in cycling, Vo2 in arm work was at maximal effort only 22% lower than in leg exercise while the difference in fH was insignificant. No differences were found in arm work between the results obtained at any work level in sitting and standing body positions. The only postural difference in arm work was a 13% higher work load achieved at maximal effort when standing than when sitting. Differences in fH between arm and leg exercise were much smaller for the same Vo2 than for the same work load and were time dependent. While fH quickly leveled off in leg exercise, fH in arm cranking rose steadily during the first 6 min of work which created the fH differences observed in the 7-8 min of submaximal arm and leg exercise. At submaximal work levels a tendency to synchronize the respiratory frequency with the frequency of the rotatory movements was more apparent in arm cranking than in cycling.

136. Vollestad NK, Wesche J & Sejersted OM (1990): Gradual increase in leg oxygen uptake during repeated submaximal contractions in humans. .J.Appl.Physiol 68, 1150-1156.

Department of Physiology, National Institute of Occupational Health, Oslo, Norway. The study examines whether muscle oxygen consumption VO2 increases gradually during repeated submaximal isometric contractions. Six subjects made two-legged isometric quadriceps contractions at 30% maximal voluntary contraction for 6 s with 4 s of rest between until exhaustion (58 +/- 8 min). Blood samples were taken from the femoral vein and artery, and blood velocity was recorded by ultrasound-Doppler technique in the femoral artery. Blood flow was calculated from velocity and artery diameter values. Leg VO2 increased sixfold within the 1st min of exercise. A further doubling of the VO2 was seen during the remainder of the exercise, reaching 307 +/- 22 ml/min at exhaustion. This latter increase was due to a 54% increase in blood flow and a 34% increase in oxygen extraction. After 20 min of recovery VO2 was still 75% higher than pre-exercise values. The results show a twofold increase in energy demand of the working muscle during repeated constant-force isometric contractions. The increased energy cost of contraction is probably localized at the cellular level, and it parallels fatigue determined as decreased force-generating capacity.

137. Wanta DM, Nagle FJ & Webb P (1993): Metabolic response to graded downhill walking. Med.Sci.Sport Exerc. 25,159-162.

Biodynamics Laboratory, University of Wisconsin, Madison 53706. Compared with level walking or running, progressive downhill walking or running requires a decreasing energy cost to some minimum where the cost again increases with further decrements in grade. Margaria estimated this minimum occurs at a -9% grade. In this study an attempt was made to more precisely track the energy cost curve in progressive downhill treadmill walking. Ten men, mean age 22.0 +/- 2.5 yr, volunteered as subjects. After VO2max determinations the subjects attended two downhill walking sessions. Each subject performed 14 randomly ordered walking bouts of 6 min in duration, at speeds of 90 and 105 m.min-1. The grades used were 0, -3, -6, -9, -12, -15, and 18%. Gas exchange measurements were obtained by open circuit spirometry during each work bout. Heart rate was monitored continuously and the stride frequency was counted by direct observation during each walking bout. Net VO2 values decreased with decrements in grade to 9, 12% for the respective speeds of 90 and 105 m.min-1. The group mean net VO2 minimums at -9 and -12%, however, were not significantly different (P > 0.05) from the group mean values at -6 and -15% at 90 m.min-1, or between -9 and -15% grades at 105 m.min-1. Group mean net VO2 values at 0, -3, and -18% were significantly different (P < 0.05) from net VO2 values for the other grades at 90 m.min-1 walking. At 105 m.min-1, mean net VO2 values at 0, -3, -6, and 18% were significantly different (P < 0.05) from net VO2 values at the other grades. We conclude that the energy cost curve for downhill walking does not precisely conform with the view that the minimum cost occurs at -9% grade. While a reasonable approximation, our group data suggest that this point is variable, occurring between -6 and -15% grade depending upon an individual's walking characteristics and walking speed. We also present a rationale to explain the energy cost curve observed during progressive downhill walking.

138. Welbergen E, Kemper HCG, Knibbe JJ, Toussaint HM & Clysen L (1991): Efficiency and effectiveness of stoop and squat lifting at different frequencies. Ergonomics, 34, 613-624.

Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands. The study investigated the effects of frequency (10 and 20 lifts/min) and technique (squat and stoop) of repetitive lifting of a barbell (19 kg) on the relationship between mean power output (Pm) and energy cost in 9 male power-lifters. Oxygen uptake (VO2) was measured directly and continuously and power output was deduced from film analysis using an inverse dynamic analysis. Power output and VO2 were significantly greater for squat than for stoop lifting at the same frequency. The mechanical efficiency (ME), defined as Pm divided by the energy equivalence of VO2, increased from 12% at rate 10 to 18.5% at rate 20, but there was no significant difference between the two techniques. The effectiveness (EF), defined as the productive external power output (only work done on the barbell) divided by the energy equivalence of VO2, was significantly higher for the stoop lift than for the squat lift. E.F is judged as a more useful measure than ME for characterizing the relative energy cost of a lifting task.

139. Welle SL, Seaton TB & Campbell RG (1986): Some metabolic effects of overeating in man. Am.J.Clin.Nutr. 44, 718-724.

Metabolic responses to 20 days of overeating were examined in five healthy volunteers. Overfeeding caused a variable increase (1-18%) in basal metabolic rate but no change in metabolic rate during light exercise. Postprandial resting metabolic rate was 8-40% higher (mean 18%) during overeating. The increase in oxygen consumption during a norepinephrine infusion was the same before (20 +/- 2%) and after (17 +/- 3%) overfeeding. Overfeeding elevated basal insulin concentrations in all subjects and increased the insulin response to intravenous glucose in four of five subjects. Overfeeding did not significantly alter mean serum T3 concentrations or erythrocyte 86Rb uptake (an index of Na+,K+-ATPase activity). These data do not confirm reports that overfeeding increases metabolic rate more during exercise than during rest. They also suggest that the increase in resting metabolic rate during overfeeding is not caused by increased responsiveness to norepinephrine or increased serum T3 concentrations.

140. Wilson GD & Sklenka MP (1983): A system for measuring energy cost during highly dynamic activities. J.Sports Med. 23, 155-158.

It has been suggested that the widely used portable respirometers (eg Max Planck) might be restrictive in some energy cost measurement situations. Therefore an alternative portable system made up of easily obtainable and inexpensive pieces was designed and compared to the Max Planck during a fastpaced game (raquetball). After play with each system, sixteen subjects were asked to complete a questionnaire relative to how the system affected their movement, their skill performance, and their comfort during play. The newly designed system fared statistically significantly better with respect to both movement and comfort. Thus, it appears that the modified portable system is to be preferred in racquet sport energy cost studies where the movement and comfort limitations of the more commonly used respirometers become significant and restrictive.

141. Winsmann FR & Goldman RF (1976): Methods for evaluation of load-carriage systems. Percept.Mot.Skills, 43, 1211-1218.

In an effort to evaluate the effectiveness of a new load-carriage system on man, energy cost studies were done comparing the new system with a standard load-carriage. Three different methods of treadmill walking were used for the comparison: (1) investigator controlled treadmill speed, (2) subject controlled treadmill speed, and (3) heart-rate controlled treadmill speed. Although none is entirely new, these three approaches provide practical means to measure the cost of work. Since there were no statistically significant differences between the two load-carriage systems, it was concluded that as long as weight is properly distributed over the body, weight per se is the most important: factor in load carriage rather than the specific load-carriage system design.

142. Wyndham CH, Van der Walt WH, van Rensburg Awl, Rogers GG & Strydom NB (1971): The influence of body weight on energy expenditure during walking an a road and on a treadmill. Int.Z.angew.Physiol. einschl.Arbeitsphysiol. 29, 285-292.

Four measurements of oxygen consumption were made on 8 subjects (varying in weight from 54.5-66.1 kg) at each of 3 speeds of walking (3.2, 4.8 and 6.4 km/hr) both on a treadmill and a road. Correlations between weight and oxygen consumption of 0.76-0.96 were significant at the 0.1% level of significance, at all three speeds on both treadmill and road. The relationship between body weight and oxygen consumption is linear and is markedly affected by speed. The slope of the linear regression lines of oxygen consumption on body weight increased hyperbolically with an increased in speed. Mean oxygen consumptions at 3.2 and 4.8 km/hr were significantly higher on the road but not at 6.4 km/hr. Curves of 02 consumption/speed are nonlinear and are markedly affected by body weight; both the intercept on the vertical axis and slope increases linearly with body weight.

143. Zarandona JE, Nelson AG, Conlee RK & Garth Fisher A (1986): Physiological responses to hand-carried weights. Physician .Sportsmed. 14, 113-120.

Thirty trained men carrying either nothing, 1-lb weights, or 5-lb weights in each hand were tested on a motorized treadmill. The purpose was to determine whether using hand-held weights elicits a pressor reflex, in which heart rate and BP rise disproportionately to oxygen consumption VO2 VO2 was measured during walking and running to see if it changed in proportion to heart rate response. Both walking and running while carrying 5-lb weights produced significant increases in VO2 but only walking produced significant differences in heart rate. The oxygen pulse (the amount of oxygen used per heart beat) was not different for any of the three treatments. The authors concluded that carrying weights in the hands can help increase the training intensity for walkers or joggers who cannot or do not wish to jog or run at a higher speed.

144. Zarrugh MY & Radcliffe CW (1978): Predicting metabolic cost of level walking. Eur.J.Appl.Physiol 38, 215-223.

Energy expenditure in walking is usually expressed as a function of walking speed. However, this relationship applies only to freely adopted step length-step rate patterns. Both the step length and the step rate must be used to predict the energy expenditure for any combination of step length and step rate. Evidence on seven subjects indicates that the energy demand for such a combination can be determined by conducting two experiments. In the first, the subject is allowed to freely choose his own walking pattern to achieve a set of prescribed speeds. In the second, the speed is kept constant but the subject is forced to adopt a range of prescribed step rates. The results of the two experiments combined yield enough data to make possible the determination of the energy equation of the pattern, encompassing both "free" and "forced" gaits. Results show that the freely chosen step rate requires the least oxygen consumption at any given speed. Any other forced step rate at the same speed increases the oxygen cost over that required for the "free" step rate.

Foreign language references

1. Frauendorf H. Gelbrich W. Vildosola J & Kuchler G (1989): [The effect of increased environmental temperature on the behavior of physiologic parameters in bicycle ergometry within the scope of the physical endurance limit]. Z.Gesamte.Hyg. 35, 354-357.

For determination of the endurance limit range, 8 healthy male probands aged between 20 and 26 years loads had carried out for one hour on a bicycle ergometer at an ambient temperature of +20 degrees C, +28 degrees C and +35 degrees C. Staying in an ambient temperature of 35 degrees C leads to a decrease in the physical endurance limit in an order of magnitude of 10 W. At 20 degrees C, in the endurance range the following values result (mean +/- s): load 68+/10.3 W. heart rate 113.6 +/- 5.8 beats per min., net heart rate 31.8 +/- 2.4 beats per min., oxygen uptake 1340 +/- 170 ml per min., auditory canal temperature 36.5 +/- 0.24 degrees C, sweat rate 275 +/- 143 g. At 35 degrees C, the endurance limit is attained at the following values: 57 +/10.6 W. heart rate 125 +/-11.8 beats per min., net heart rate 27.4 +/- 3.6 beats per min., oxygen uptake 1210 +/-130 ml per min., auditory canal temperature 37.2 +/- 0.3 degrees C, sweat rate 577 +/- 96 g.

2. Rossi A, Calsamiglia G. Ricciardi L, Bartoletti S. Orlandi M, Sardi C, Galli N & Minelli R (1984): [Stima dell'impegno energetico e cardiovascolare del giocatore di basket nel corso di una gara]. Boll.Soc.ltal.Biol.Sper. 60, 581 -587.

Energy expenditure was evaluated for 6 basket players while exercising on a cycle ergometer. Oxygen consumption (VO2), pulmonary ventilation (VE), heart rate (HR), respiratory quotient (RQ) and other parameters were estimated at various levels of load (25 Watt each step off 3 minutes duration), up to a submaximal load of 175 Watt. The same subjects participated in a regular basket game and their heart rate was continuously stored on a tape recorder (Holler). Arterial blood pressure was also taken whenever possible (time cut, etc.). From the laboratory and field data, estimates were made for the oxygen consumption and energy cost of the game. The latter had a net value of 0.1339 Kcal.kg^-1.min^-1.

3. Wirths W (1979): [Differences in energy expenditure for selected activities under controlled and uncontrolled conditions].. Z.Ernahrungswiss. 18, 250-257.

Experiments with the Max-Planck respirometer were made to determine the energy expenditure. Four kinds of comparable tests were made under standard conditions and ad libitum individual: walking on solid, level ground with light clothing, in high lace boots (walking-speed 5 km/h), walking with 10 kg resp. 20 kg load on level, solid ground (running-speed 10 km). The energy expenditure under standard conditions is much higher than in the working-elements ad libitum speed and distance. Many persons overestimate their personal energy expenditure which is a reason for a positive energy balance succeeded by overweight.

(introductory text...)

1. Ategbo EA, van Raaij JM, de Koning FL & Hautvast JG (1995): Resting metabolic rate and work efficiency of rural Beninese women: a 2-y longitudinal study. Am.J.Clin.Nutr. 61, 466-472.

Faculty of Agricultural Sciences, Benin National University, Cotonou, Netherlands. This study was performed on 34 female farmers in northern Benin during 2 consecutive years. Body composition, energy intake, energy expenditure, resting metabolic rate (RMR), and energy cost of cycling on a bicycle were measured in three periods per year. Energy intake showed seasonal fluctuations of approximately 1.7 MJ/d in 1990 and 0.6 MJ/d in 1991. Body weight fluctuated between periods, with the lowest weight in preharvest periods. Observed changes in body weight were 2.6 +/- 2.3 and 0.9 +/- 1.7 kg in 1990 and 1991, respectively. The same pattern was observed in both fat mass and fat-free mass. RMR, energy cost of cycling, and delta work efficiency did not show any seasonal changes. It is concluded that metabolic adaptation, as a response to a seasonal food shortage up to 15% of average daily intake, will not occur.

2. Blackburn MW & Calloway DH (1976): Basal metabolic rate and work energy expenditure of mature, pregnant women. J.Am.Diet.Assoc. 69, 24-28.

Resting and working metabolic rates and physical fitness of twenty-one mature women were studied at various intervals during the last half of pregnance and in sixteen of them again eight to twelve weeks postpartum. Basal rate (BMR) was increased more than body weight during pregnancy, and there was a small drop in BMR per unit body mass near term. Data on lean body mass (40K) suggest that the small terminal fall in BMR is not explained by a shift in body composition toward increased fat or water. The increase in energy cost of work paralleled the gain in body weight during pregnancy. Net energetic efficiency thus appeared to be higher for work performed during pregnancy, if recovery rates are assumed to be uniform. However, according to their heart rate reponses to fixed hard work, the women were less fit during pregnancy than they were postpartum, with the level of fitness decreasing as pregnancy advanced. The prolonged rate of recovery suggests that oxygen uptake may be increased for a longer period after work in the pregnant woman. If this is true, energy expenditure will be seriously underestimated by the application of energy cost figures obtained in the conventional manner.

3. Blackburn MW & Calloway OH (1976): Energy expenditure and consumption of mature, pregnant and lactating women. J.Am.Diet.Assoc. 69, 29-37.

Activity patterns, energy expenditure, and energy and protein consumption of mature women were determined during pregancy and lactation. Homemakers of average economic status from a mixed population were not significantly more active than teenage women, but the range of activities was greater. Average energy output for the latter half of gestation was 2,200 to 2,300 kcal per day; per unit of body weight, the mean was 32.5 +/- 4 kcal per kilogram for the twenty-week period. A small decline of 6 per cent in energy expenditure was noted near term. Allowing for deposition of fetal and material tissue, the average metabolizable energy need for this group was about 35 to 36 kcal per kilogram for the latter half of pregnancy. These data show that a pregnant woman of reference body weight (68 kg.) may vary in energy output by 800 to 900 kcal per day, depending on occupation. Homemakers with small children and especially those who work outside the home constitute a high energy work category. Thus, the need for considering work pace and work load, as well as body mass, in estimating the energy requirement during pregnancy was confirmed. Average daily energy intake reported was 1,955 kcal or 28.5 kcal per kilogram for the latter half of gestation. A mean protein intake of 1.17 gm. per kilogram per day represented 17 per cent of gross energy consumed. It is questionable whether the energy level consumed by these women was sufficient to maintain positive nitrogen balance on the days recorded. Lactating homemakers expended an average of 30 kcal per kilogram per day, exclusive of milk production. Energy intake was 30 kcal per kilogram, and was equal to 74 per cent of need when adjusted for milk production. Non-lactating women expended 34 kcal per kilogram per day, 13 per cent above the values for lactating women. Average energy intake of non-lactating women was 19 kcal per kilogram, with protein intake representing 19 per cent of energy consumed for both groups.

4. Blackburn MW & Calloway DH (1985): Heart rate and energy expenditure of pregnant and lactating women. Am.J.Clin.Nutr. 42, 1161-1169.

Data on heart rate and oxygen consumption of 21 mature pregnant women, and of 16 of them postpartum, were examined for evidence of the suitability of heart rate as an index of energy expenditure during pregnancy. Energy expenditure, measured by indirect calorimetry, and heart rate were recorded with subjects at rest (Iying, sitting, and standing) and working (on a treadmill and cycle ergometer) at three different levels. Energy expenditure (EE) and heart rate (HR) were highly correlated during the second half of gestation and postpartum. Both EE and HR were affected by pregnancy state, but the relationship between HR and EE was not changed. Slopes of regression of two linear components of EE/HR relationship were 0.01-0.02 for resting, and 0.05-0.06 for working measures. The slopes under resting and working conditions are significantly different from zero, and from each other. Prediction of EE from HR is unreliable in the range 80-120 beats/min where resting and working HRs overlap.

5. Bruce V, Crosby LO, Reicheck N. Pertschuk M, Lusk E & Mullen JL (1984): Energy expenditure in primary malnutrition during standardized exercise. Am.J.Phys.Med. 63, 165-174.

When eight malnourished females without organic disease were subjected to a controlled treadmill exercise test, they expended less total energy than females of normal body weight. The malnourished subjects consumed less oxygen than the control subjects, but oxygen consumption increased with increasing work load. The resting energy expenditure of the malnourished subjects was less than predicted values, but body composition as determined by muscle mass, total body water and thyroxine levels were within normal limits. Although decreased energy expenditure associated with malnutrition, has been attributed to decreased oxygen transport and altered hemoglobin, the malnourished subjects in this study did not have reduced hemoglobin levels. Metabolic adaptation may have occurred in order to improve the efficiency of aerobic metabolism. In order to confirm this theory, energy expenditure should be assessed under conditions of maximal oxygen intake.

6. Bunc V & Heller J (1994): Energy cost of running in young and adult female athletes. Ergonomics, 37, 167-174.

Faculty of Physical Education and Sports, Charles University, Prague, Czech Republic. Maximal oxygen uptake VO2 max.kg-1) and energy cost of running were determined on the treadmill in groups of differently trained young and adult athletes. The VO2 max.kg-1 was in all cases higher in adults than in young athletes. These differences were significant (p < 0.05) in long-distance runners (n = 12, mean age = 24.2 +/- 2.2 vs 17.3 +/- 0.9 yrs, mean VO2 max.kg-1 = 66.9 +/- 4.2 vs 58.2 +/- 4.3 ml.min-1.kg-1), and in middle-distance runners (10, 22.9 +/- 2.8 vs 16,16.6 +/0.8, 62.3 +/- 3.7 vs 56.1 +/- 2.8); in canoeists these differences were non-significant ('7, 21.1 +/2.1 vs 16.0 +/- 2.3 vs 8, 48.2 +/- 2.6). Values of energy cost of running - coefficients of energy demand of running c, which indicates how much energy is required to transfer 1 kg of body mass on a distance of 1 m - were lower in adult athletes than in young athletes. These differences were significant (p < 0.05) only in long-distance runners (3.69 +/- 0.15 vs 3.84 +/0.14 J.kg-1.m-1). In middle-distance runners (3.67 +/- 0.19 vs 3.76 +/- 0.18), and in canoeists (3.84 +/- 0.14 vs 3.86 +/- 0.18) these differences were non-significant. It is concluded that the differences in energy cost of running between trained adult and young female athletes are probably associated with differences in adaptation to the running, and with the technique of movement. Differences in running speed (sports performance) between adult and young athletes are associated with differences in VO2 max.kg-1 and c.

7. Charteris J. Scott PA & Nottrodt JW (1989): Metabolic and kinematic responses of African women headload carriers under controlled conditions of load and speed. Ergonomics, 32, 1539-1550.

Recent investigations have argued for the metabolic efficiency of headloading as a mode of load-carriage, and have included proposals of an energetic 'free-ride' for loads under 20% bodymass. Our own energy-cost analyses on laboratory-habituated African women occupational headloaders is used to evaluate the free-ride hypothesis, but more especially to throw new light on the kinematics of foot-floor contact patterns. Under headloading there is a tendency for the impact-receiving mechanisms of the foot to be less effective. However, a delayed heel-rise later in the step increases stability of support by reducing the duration of forefoot-only contact. Plantar thrust under headloading has a relatively longer duration, which may have force-velocity implications for the propulsive musculature.

8. de Boer JO, van Es AJ, Roovers LC, van Raaij JM & Hautvast JG (1986): Adaptation of energy metabolism of overweight women to low-energy intake, studied with whole-body calorimeters. Am.J.Clin.Nutr. 44, 585-595.

In 14 overweight women, 24-h energy expenditure (EE) was measured in a whole-body indirect calorimeter: before weight reduction (100% diet), after 1 wk on a 4.2-MJ diet, after 8 wk on 4.2-MJ diet, after weight reduction on 100% diet. Data of two subjects were excluded. Mean body weight declined from 93.3 +/-7.4 'mean +/- SD) to 83.4 +/- 7.7 kg; 24-hEE decreased from 10.52 +/- 0.83 MJ on the 100% diet to 9.58 +/- 0.75 MJ on the 4.2-MJ diet. After 8 wk. 24-hEE had decreased by 15% of the initial 24-hEE to 8.92 +/- 0.65 MJ. After refeeding (1 wk), it increased to 9.45 +/- 0.75 MJ. Calculated energy requirement before weight reduction was 10.62 +/- 0.88 MJ/day; after weight reduction, 9.39 +/- 0.79 MJ/day. The decrease was more than that predicted from the change in body weight and body composition. An adaptation probably occurs, which may be metabolic.

9. Ebbeling CJ, Hamill J & Crussemeyer JA (1994): Lower extremity mechanics and energy cost of walking in high-heeled shoes. J.Orthop.Sports Phys.Ther. 19, 190-196.

Dept. of Exercise Science, University of Massachusetts, Amherst 01003. In today's society, many women wear high-heeled shoes. However, the effect that shoes of different heel heights have on the biomechanics and energy cost of gait has not been fully investigated. In the present study, the energy cost and the lower extremity mechanics in shoes of different heel heights (1.25 cm, 3.81 cm, 5.08 cm, and 7.62 cm) were examined in 15 female subjects, seven of whom could be considered experienced high-heel wearers. Kinematic data from high-speed video and kinetic data from a force platform were collected to describe lower extremity mechanics while subjects walked overground at a speed of 4.2 km/hour. Heart rate and oxygen consumption were monitored while subjects walked on a treadmill, also at 4.2 km/hour. There were no significant differences in any of the parameters as a function of experience in wearing high heels; therefore, the data were pooled for further analysis. Analysis of the biomechanical data revealed that ankle planter flexion, knee flexion, vertical ground reaction force, and the maximum anteroposterior braking force increased as a function of heel height. In addition, the timing of the subtalar and knee joint action was asynchronous with the increase in heel height. Metabolically, heart rate and oxygen consumption also increased with heel height. There were many significant differences between the 5.08-cm and the 7.62-cm heel conditions. Therefore, to maintain comfort and decrease the risk of injury, women may be advised not to wear shoes with a heel height greater than 5.08 cm.

10. Esmail S. Bhambhani Y & Brintnell S (1995): Gender differences in work performance on the Baltimore Therapeutic Equipment work simulator. Am.J.Occup.Ther. 49, 405-411.

Department of Occupational Therapy, University of Alberta, Edmonton, Canada. The purposes of this study were to (a) establish biomechanical and physiological normative data for healthy young women performing three tasks on the Baltimore Therapeutic Equipment work simulator (BTE): wheel-turn, push-pull, and overhead-reach; and (b) compare these data with previously reported values for healthy men of a similar age group. METHOD. Twenty women completed five test sessions: (a) task familiarization on the BTE to determine the work intensity that was perceived as hard on the Borg scale, (b) incremental test on an arm crank ergometer to measure peak oxygen uptake VO2 and peak heart rate (HR), and (c) one of the three tasks in random order for 4 min during the next three sessions. Physiological responses were monitored with a metabolic cart interfaced with an electrocardiogram. RESULTS. Torque, work, and power during the three tasks were significantly higher (p < .05) in men than in women. The absolute VO2 (L.min-1) during these tasks was higher in men, but when the VO2 was calculated relative to body weight (ml.kg1.min-1), no significant (p > .05) gender differences were observed. Computation of energy expenditure relative to body weight and power output (cal.kg-1.W-1) indicated that women expended significantly (p < .05) more energy than men. No significant (p > .05) gender differences were observed for VO2 and HR when the values were expressed as a percentage of their respective peaks. CONCLUSIONS: Findings indicated that (a) the functional work capacity is significantly lower in women than in men, (b) women are less efficient than men when the energy expenditure is expressed per unit of body weight and power output, and (c) the relative physiological stress in men and women is similar under these conditions.

11. Falls HE & Humphrey LD (1976): Energy cost of running and walking in young women. Med.Sci.Sports, 8, 9-13.

The energy cost of level walking and level and grade running was determined in 7 active women with max VO2 = 50.7 ml/kg-mint Speeds investigated were 4 to 8 km/hr walking and 8 to 14.5 km/hr running. The validity coefficients of several procedures for estimating energy expenditure during locomotion [4 for running (6)(11)(16)(17); 3 for walking (6)(12)(17)] were determined. Correlation coefficients between actual and predicted values were 0.949 to 0.951 with standard errors of estimate 0.79 to 0.80 kcal/kg-hour for walking and 0.856 to 0.975 with standard errors of estimate 0.40 to 0.60 kcal/kg-hour for running. VO2 and kcal energy cost values were similar to those previously reported on men at equivalent walking and running speeds. Efficiency of running based on lift work done was about 25%. Lift work for women was slightly less than values previously reported for men at walking but was slightly more at running. These differences did not appear to have a significant effect on energy expenditure.

12. Foster GD Wadden TA, Kendrick ZV, Letizia KA, Lander DP & Conill AM (1995): The energy cost of walking before and after significant weight loss. Med.Sci.Sport Exerc. 27, 888-894.

University of Pennsylvania School of Medicine, Philadephia, USA. The purpose of this study was to determine whether significant weight loss reduced the energy cost of activity more than that expected based on decreased body weight. Standing energy expenditure was measured and subtracted from the total energy cost of walking to determine ambulatory energy expenditure (AEE). The energy cost of walking was determined in 11 obese women at baseline, week 9 [after 8 wk of a 1758-3349 kJ.d-1 diet], and week 22 (after 2 wk of weight stability). AEE accounted for 80% of the energy cost of walking. Body weight was the principal determinant of AEE, but the relationship was not 1:1. Subjects reduced body weight by 13% at week 9 and 21% at week 22. Analyses which controlled for the relationship between AEE and weight at baseline, showed no change in AEE at week 9. By contrast, at week 22, AEE was reduced more than expected based on a lower body weight. These findings suggest that after significant weight loss, reduced-obese persons will expend less energy for the same activity, even after accounting for the decrease in body weight. These data also suggest that weight-based estimates of exercise energy expenditure may be inappropriate after significant weight loss.

13. Heglund NC, Willems PA, Penta M & Cavagna GA (1995): Energy-saving gait mechanics with head-supported loads. Nature, 375, 52-54.

Pharos Systems Inc., South Chelmsford, Massachusetts 01824, USA. In many areas of the world that lack a transportation infrastructure, people routinely carry extraordinary loads supported by their heads, for example the Sherpa of the Himalayas and the women of East Africa. It has previously been shown that African women from the Kikuyu and Luo tribes can carry loads substantially more cheaply than army recruits; however, the mechanism for their economy has remained unknown. Here we investigate, using a force platform, the mechanics of carrying head-supported loads by Kikuyu and Luo women. The weight-specific mechanical work, required to maintain the motion of the common centre of mass of the body and load, decreases with load in the African women, whereas it increases in control subjects. The decrease in work by the African women is a result of a greater conservation of mechanical energy resulting from an improved pendulum-like transfer of energy during each step, back and forth between gravitational potential energy and kinetic energy of the centre of mass.

14. Jones BH, Knapik JJ, Daniels WL & Toner MM (1986): The energy cost of women walking and running in shoes and boots. Ergonomics, 29, 439-443.

The purpose of this study was to determine the difference in energy cost for women walking and running in shoes and boots. Seven subjects wore athletic shoes (mean weight=514+-50g) and leather military boots (mean weight=1371+-104g) at three different walking speeds (4.0, 5.6 and 7.3 km/hour) and two running speeds (8.9 and 10.5 km/hour). During each walking and running trial oxygen uptake VO2 ml.kg^-1min^-1) was measured. The VO2 for women wearing boots were significantly higher (P<0.05) than or shoes for both walking and running, with exception of the slowest walking speed. The average increment in energy cost was 1.0% per 100-g increase in weight per pair of footwear. These results are similar to those reported for men from other studies which found increments in energy cost of 0.7 to 0.9% per 100-g increase in weight of footwear.

15. Jones CDR, Jarjou MS, Whitehead RG & Jequier E (1987): Fatness and the energy cost of carrying loads in African women [letter]. Lancet, 2, 1331-1332.

The energy cost of walking while carrying loads (0-45% of body weight) was measured in 8 Gambian women in a whole-body calorimeter. The results for 4 women with low body-fat content showed the same relation between proportional increase in energy expenditure and external load as reported by Maloiy et al (1986). All women studied could carry 40% of their FFM either as body fat or as external load, or as combination of the two, before they needed to increase their energy expenditure. Beyond this point, however, extra loads resulted in the anticipated proportional increase in energy expenditure.

16. Kirk J & Schneider DA (1992): Physiological and perceptual responses to load-carrying in female subjects using internal and external frame backpacks. Ergonomics, 35, 445-455.

Department of Health, Sport, and Leisure Studies, Northeastern University, Boston, MA 02115. Eleven female subjects (ages 18-3:3 years) walked on a motor-driven treadmill at 86 m/min for 1 h carrying 33% of their body weight in a backpack. The grade of the treadmill alternated every 15 min between 0 and 3%. Each subject carried an internal frame backpack for one trial and an external frame backpack for another trial on a separate day. The variables measured during the two load-carrying experiments included oxygen consumption VO2 heart rate (HR), respiratory exchange ratio (R), minute ventilation VE, and the ratings of perceived exertion for the chest (RPE-chest), shoulders (RPE-shoulders), and legs (RPE- legs). When oxygen uptake measured during load-carrying was expressed as a percentage of VO2max the average values were 40.1% (63.5% HRmax) at 0% grade and 49.0% (69.6% HRmax) at 3% grade for both backpacks. No significant differences were found between the two packs for any of the metabolic, cardiorespiratory, or perceptual variables measured. Changes in treadmill grade had a significant effect on VO2 HR, and VE, regardless of the type of pack carried. Minute ventilation was the only physiological response to load-carrying that increased significantly as exercise duration increased. The values for RPE-chest, RPE-shoulders, and RPE-legs were significantly increased by both exercise time and treadmill slope, regardless of the type of pack frame carried. Thus despite relatively constant metabolic responses over time, increased perception of effort could compromise completion of the load-carrying task. It was concluded that differences in backpack frame design were not great enough to produce significant differences in the energy cost or perception of carrying a moderately heavy load on the back.

17. Long Danoff P & Danoff JV (1982): Energy cost and heart rate response to static and dynamic leg exercise. Arch.Phys.Med.Rehabil. 63, 130-134.

The energy cost VO2 and heart rate (HR) response to variable-load static (isometric) and dynamic (isotonic) leg exercise were determined in 5 young women who performed 5-minute bouts of leg extension while in a sitting position on a weight-loaded dynamometer using 4 loads for each type of contraction. Results indicated that VO2 and HR increased as apparently linear functions of workload for both types of exercise, although a difference in the amount of change was observed. When the 2 types of exercise were compared using the same resistance load, the dynamic bouts required a significantly greater net VO2 and HR. At a given VO2 level, HR was higher during static exercise. Net HR also appeared to increase more steeply as a function of VO2 during static than during dynamic exercise. It was concluded that bouts of static and dynamic exercise which employ equal loads for an equal period of time are not physiologically equal or directly comparable since the VO2 and HR response are not the same for the 2 types of exercise. For this reason, VO2 and HR response should not be used interchangeably for relating static to dynamic workloads, or when prescribing exercise for the purpose of patient conditioning or rehabilitation.

18. Maloiy GMO, Heglund NC, Prager LM, Cavagna GA & Taylor CR (1986): Energetic cost of carrying loads: have African women discovered an economic way? Nature, 319, 668-669.

When travelling in East Africa one is often surprised at the prodigious loads carried by the women of the area. It is not uncommon to see women of the Luo tribe carrying loads equivalent to 70% of their body mass balanced on the top of their heads. Women of the Kikuyu tribe carry equally large loads supported by a strap across their foreheads; this frequently results in a permanently grooved skull. Recent experiments on running horses, humans, dogs and rats showed that the energy expended in carrying a load increased in direct proportion to the weight of the load for each animal at each speed, that is, carrying a load equal to 20% of body weight increased the rate of energy consumption by 20%. The purpose of the present study was to determine whether these African women use specialized mechanisms for carrying very large loads cheaply. Both the Luo and Kikuyu women could carry loads of up to 20% of their body weight without increasing their rate of energy consumption. For heavier loads there was a proportional increase in energy consumption, that is, a 30% load increased energy consumption by 10%, a 40% load by 20% and so on. It is suggested that some element of training and/or anatomical change since childhood may allow these women to carry heavy loads economically.

19. Manore MM, Berry TE, Skinner JS & Carroll SS (1991): Energy expenditure at rest and during exercise in nonobese female cyclical dieters and in nondieting control subjects. Am.J.Clin.Nutr. 54, 41-46.

Department of Family Resources and Human Development, Arizona State University, Tempe 85287-2502. The purpose of this research was to determine if resting energy expenditure (REE) and exercise energy expenditure (EKE) differed between nonobese female cyclical dieters (n = 11) and nondieting control subjects (n = 12). Dieters were defined as having intermittent periods of caloric restriction (less than or equal to 4184 kJ/d, or less than or equal to 1000 kcal/d) for greater than or equal to 7-10 d four times in the preceding year. Dieters were significantly (P less than 0.01) heavier (66 vs 57 kg) and fatter (26% vs 21% body fat) than controls subjects whereas fat-free tissue was similar in both groups. Dieters had significantly (P less than 0.003) lower relative REE than did control subjects (2.8 vs 3.1 mL O2.kg-1.min-1; 79 vs 92 kJ.kg body wt-1.d-1, or 19 vs 22 kcal.kg body wt-1.d-1) but absolute REE (kJ/d, or kcal/d) was similar. Regardless of the workload examined, relative EKE was significantly (P less than 0.009) lower in dieters than in control subjects whereas absolute EEEs were similar at each workload. Results indicate an increased efficiency of food utilization during exercise in dieters but no difference in absolute REE. In addition, repeated bouts of dieting may alter body composition.

20. Morrow SK, Bishop PA & Teare Ketter CA (1992): Energy costs of self-paced walking with handheld weights. Res.Q.Exerc.Sport, 63, 435-437.

This study investigated the effects of exercising with hand held weights on the rate of self-paced walking to assess whether subjects adjust their pace to compensate for the extra weight, thus stablizing the increased energy costs of using the weights. Subjects were 18 physically active women. When self-selected walking speeds had been established for each subject, the energy cost of walking (1.70-1.78 m/see) while carrying no load, 0.5 kg handweights, and, 1.4 kg handweights was measured. Mean VO2s measured for the 3 activities were 19.4 ± 4.6, 19.5 ± 5.5, and 19.9 ± 3.7 ml/kg BW respectively. The slight increase while carrying the handweights was not statistically significant, although changes in heart rate and walking speed were. [not original abstract].

21. Richardson M (1966): Physiological responses and energy expenditures of women using stairs of three designs. .J.Appl.Physiol 21,1078-1082.

To determine the effect of differences in architectural designs for stairways on the energy expenditure, heart rate, and other cardiovascular responses of women when using stairs, three different combinations of riser heights and tread widths were tested by using an adjustable stairstep treadmill especially developed for this purpose. Energy expenditures of eight women were significantly different for using stairs of three designs, with a mean cost of 7.8, 13.4 and 15.3 (mean, 12.1) for ascending; and 5.3, 7.4, and 8.4 (mean, 7.1) car/kg-m vertical distance for gentle, intermediate, and steep (27°, 38°, and 40°) slopes, respectively. Pulse rate and systolic blood pressure also varied significantly with stairs design, with these responses ranking the designs in the same order as did energy expenditure.

22. Richardson M & McCracken EC (1966): Work-surface levels and human energy expenditure. J.Am.Diet.Assoc. 48, 192-198.

Six typical hand-arm motions were performed by two women at counter heights of 28 and 40 in. A 35 per cent increase in energy expenditure over standing quietly was obtained. Increases for each motion performed at the lower level did not differ significantly from one another. Therefore, one-arm motion was studied intensively to determine ranges of heights at which minimum energy was expended. Because of easy standardization of movements, the turning of a hand ergometer was selected, and the energy expended by six women at eight counter heights determined. Significantly least energy was expended between 32 and 40 in. from the floor with a 44 per cent increase over standing at rest for work at a 36 in. counter. A dough-rolling activity was investigated for five and eight women using two methods while standing and one while sitting on a chair and posture-type stool. For short experimental periods, lower values were found for standing than for rolling dough while seated; also, there were lower values at lower work-surface levels where, on standing, the application of the body weight aided the rolling process. Least total energy was expended for dough-rolling when standing at a work-surface level of 28 1/2 in.; the greatest energy, for work at a height of 33 in. when seated on a chair. Minimum expenditure for working on the stool was less than the minimum expenditure for working on the chair. A minimum increase for dough-rolling, itself, was 66 per cent over standing quietly and 111 per cent over sitting quietly. For all women, as the metabolic rate for the work increased, the individual variation decreased. Except for work when seated on a stool, where the women all expended least energy at the same level, and for work when seated on a chair, where they all spent most energy at the same level, minimum and maximum expenditures were obtained at various heights for each individual. However, no consistent relationship was found for body weight and certain anthropometric measurements when compared with energy expenditures.

23. Robertson RJ, Caspersen CJ, Allison TG, Skrinar GS, Abbott RA & Metz KF (1982): Differentiated perceptions of exertion and energy cost of young women while carrying loads. Eur.J.Appl.Physiol 49, 69-78.

Differentiated local ratings of perceived exertion from the legs and central ratings from the chest, and oxygen consumption, were determined during load carriage in seven young women. Subjects walked for 6 min at 3.22, 4.83, 6.44 or 8.05 km.h^-1 carrying (1) no load, (2) a load equal to 7.5% of body weight (mean: 4.66kg) or (3) a load equal to 15% of body weight (mean: 9.32 kg). Thus, each subject underwent 12 separate tests. The external loads were in the form of lead pellets carried in a plastic scuba belt worn around the waist. A differentiation threshold was found at 6.44 km.h^-1 for the 0% and 7.5% loads and at 4.83 km.h^-1 for the 15% load. At speeds below the threshold, the perception of exertion was similar in the legs, chest and overall. At higher speeds, exertion was perceived to be more intense in the legs than overall and less intense in the chest than overall, suggesting that the local legs signal was the dominant factor in shaping the overall sensation of exertion. The oxygen uptake was greater for the 15% load than for either the 0% or 7.5% loads, but was similar for the 0% and 7.5% loads. Findings suggested a critical weight limit for external loads that could be transported without increasing the metabolic cost beyond that required to move the body weight alone. The limit fell between 7.5% and 15% of the body weight. When oxygen uptake was expressed per kg of total weight transported, there was no loss of metabolic efficiency while carrying loads up to 15% of the body weight.

24. Rodgers CD, VanHeest JL & Schachter CL (1995): Energy expenditure during submaximal walking with Exerstriders. Med.Sci.Sport Exerc. 27, 607-611.

Department of Physical Education and Exercise Science, Michigan State University, East Lansing, USA. This study was designed to determine whether Exerstriding, a modified form of walking using walking sticks (Exerstriders), resulted in an augmented cardiorespiratory response and a greater energy expenditure than when walking without Exerstriders. Female subjects (23.6 +/- 4.0 yr; 58.5 +/- 5.5 kg) completed two randomly assigned trials of treadmill walking (6.7 km.h-1; 0% grade; 30 min.) with (Exerstrider (E)) and without Exerstriders (Control (C)). Mean oxygen consumption (E = 20.5 +/- 1.2 ml.min-1.kg-1; C = 18.3 +/-2.5 ml.min-1.kg), heart rate (E = 132.5 +/- 19.2 beats.min-1; C = 121.5 +/- 21.2 beats.min-1) and respiratory exchange ratio (E = .82 +/- .03; C = .78 +/- .04) were significantly greater (P < or = 0.05) while walking with Exerstriders. Total caloric expenditure was also significantly greater during the Exerstrider condition (E = 173.7 +/- 20.9 kcal; C = 140.7 +/- 27.2 kcal.). In contrast, the rating of perceived exertion did not differ significantly between the two conditions. These data suggest that Exerstriding provides a means to increase caloric expenditure during submaximal walking, a factor that may be of critical importance in enhancing health benefits - such as improved body composition and aerobic capacity - typically associated with walking programs.

25. Seitchik J (1967): Body composition and energy expenditure during rest and work in pregnancy. Am.J.Obstet.Gynecol. 97, 701-713.

The question was asked: do pregnant women pay a greater price than women not pregnant for the performance of an individual quantity of work? The ventilation reates and 02 and CO2 concentrations of inspired and expired air were measured during quiet sitting, pedaling on a bicycle ergometer, and recovery from exercise. Several parameters of body size and composition were obtained. Data were accumulated from 34 studies of nonpregnant women, 28 studies of postpartum women, and 133 studies of pregnant women. The results indicate that the energy cost of quiet sitting per unit of fat-free mass is identical in pregnant and nonpregnant women. The energy cost of this non-weight-bearing, submaximal work is similar in pregnant and nonpregnant women. Finally, among the pregnant women, those between 24 and 35 weeks pregnant were the most efficient.

26. Spaaij CJK, van Raaij JMA, de Groot LCPGM, van der Heijden LJM, Boekholt HA & Hautvast JGAJ (1994): No changes during pregnancy in the net cost of cycling exercise. Eur.J.Clin.Nutr. 48, 513-521.

Department of Human Nutrition, Wageningen Agricultural University, The Netherlands. Objective: To investigate whether work efficiency improves during pregnancy. Design: Longitudinal; energy expenditure measurements (ventilated hood system) before the onset of pregnancy and in weeks 13, 24 and 35 of gestation. Subjects: Healthy Dutch women (n = 26), recruited with advertisements in local newspapers and posters displayed in public buildings. Main outcome measures: Resting metabolic rate (RMR); metabolic rate during cycling at workloads of 30, 45, 60 and 75 W (CMRgross); post-cycling metabolic rate (PCMRgross); net energy costs of cycling (CMRnet = CMRgross - RMR); net recovery costs after cycling exercise (PCMRnet = PCMRgross - RMR). Results: RMR, CMRgross and PCMRgross increased during pregnancy; under all conditions, metabolic rates were 0.9 kJ/min higher at 35 weeks gestation than before pregnancy (P < 0.05). CMRnet and PCMRnet showed no significant change during gestation. Conclusions: Changes in metabolic rate during cycling exercise suggest that pregnancy does not induce an improvement of work efficiency.

27. van Raaij JMA, Schonk CM, Vermaat-Miedema SH, Peek MEM & Hautvast JGAJ (1990): Energy cost of walking at a fixed pace and self-paced before, during, and after pregnancy. Am.J.Clin.Nutr. 51, 158-161.

Department of Human Nutrition, Agricultural University, Wageningen, The Netherlands. Body weight, basal metabolic rate (BMR), and treadmill metabolic rate (TMR) (3.9 km/in, no elevation) were measured in 39 women at 12, 24, and 36 wk gestation and at 9 wk postpartum. Pre-pregnancy measurements were also made on 15 of the women. TMR at 36 wk (3.65 +/- 0.50 kcal/min) was significantly higher than at 24 wk (3.38 +/- 0.43 kcal/min) or at 9 wk postpartum (3.38 +/- 0.43 kcal/min). Net energy cost (TMR minus BMR) at 36 wk gestation (2.42 +/- 0.40 kcal/min) was not different from pre-pregnancy or postpartum values but was significantly higher than at 12 wk (2.28 +/- 0.39 kcal/min) and 24 wk (2.28 +/- 0.37 kcal/min) gestation. In eight women the energy cost of self-paced walking on a treadmill was measured. The absolute and net energy cost decreased sharply from 6 to 12 wk gestation (by 8% and 11%, respectively) but remained unchanged afterwards. The data suggest that in the energy requirements for pregnant women no additional allowance need be made for physical activity, even if a woman's activity pattern includes a substantial amount of externally paced work.

28. Voorrips LE, van Acker TMJ, Deurenberg P & van Staveren WA (1993): Energy expenditure at rest and during standardized activities: a comparison between elderly and middle-aged women. Am.J.Clin.Nutr. 58, 15-20.

Department of Human Nutrition, Wageningen Agricultural University, The Netherlands. To estimate energy expenditure (EE) in elderly subjects, more age-specific data are required on energy costs of standardized activities. EE was assessed by using indirect calorimetry in 28 women aged 72 +/- 4 y (mean +/- SD) and in 29 middle-aged women (42 +/- 1 y) at rest (resting metabolic rate; RMR) and during sitting, sitting with standardized arm activity, and walking on a treadmill at 3 km/in. RMR and EE during sitting, and sitting with standardized arm activity did not differ significantly between the groups, although EE expressed as a ratio of arm activity to RMR (physical activity ratio, PAR) fenced to be higher in the elderly subjects. Walking EE was significantly higher in the elderly women (16.4 +/-4.0 kJ/min) than in the middle-aged women (12.7 +/- 2.3 kJ/min), also when expressed as PAR. It is suggested that elderly women walk less efficiently. Because PARs are frequently used to estimate daily EE, it is important to note that additional age-specific data might be required.

29. Watson R & Jennings-White M (1974): Energy intake and expenditure with reference to the female physical education student. Ergonomics, 17, 23-30.

A random sample of twenty-seven 18-21 -year-old female physical education students completed dietary and activity diaries for seven consecutive days. Tables were used for calculating the subjects energy intake and expenditure. Measurements of metabolic energy were also determined using an open circuit method. Energy expenditure calculations by the table method differed from direct calculations. Unlike many studies, which have been confined to an eight hour working day, the present investigation obtained data for seven 24 hourly consecutive periods. Mean basal energy requirement was 6.53 +-0.49 x 10⁶ J/day; mean energy intake was 9.82 +2.06 x 10⁶ J/day and mean energy expenditure was 10.18 +- 10⁶ x 106 J/day. Intake varies more than expenditure. Mean daily Joule fluctuations showed a definite relationship with the college timetable. Maximum energy expenditure days coincided with minimum energy intake and vice versa. The ratio of body surface area to body mass (cms²/kg) decreased with increasing obesity.

Foreign language references

1. Seidell JC, Melchers M, Deurenberg P & van Staveren WA (1984): [Energiebesteding van een groep jonge volwassen vrouwen]. Voeding, 45, 46-49.(Abstract)

Notes: In 20 young adult women, aged 29 +- 2.8 years, resting metabolic rate (RMR) and the energy cost of some household activities were measured. The best fit was found in the correlation between RMR and body weight (W): RMR (kJ/min) = 2.80 + 0.023 W. r = 0.75. The net energy cost of a standardized activity (treadmill, 3.9 km/in) could best be predicted by body weight: E(kJ/min) = 3.04 + 0.12 W. r = 0.75. The energy cost of moderate household activities was less than could be expected from the literature, but the energy cost of strenuous activities was higher than values mentioned in the literature. However, this made little difference to total daily energy expenditure/day as seen in a comparable group of women.

4.4.3 Men & women

1. Banerjee B & Saha (1972): Effect of temperature variation in a climatic chamber on energy cost of rest and work. Environ.Res. 5, 241-247.

Energy expenditures with some common daily activities of 10 male and 10 female medical students were measured at the room temperature of 29°, and at 18° and 38° in a climatic chamber. The increased resting metabolic rate and energy cost for different activities in hot and cold temperatures were found to be not significantly higher than that for room temperature except in a few categories. The energy cost for all the activities was found to be lower than that reported in Western figures.

2. Bhambhani Y & Singh M (1985): Metabolic and cinematographic analysis of walking and running in men and women. Med.Sci.Sport Exerc. 17, 131-137.

The purposes of this study were to compare the total metabolic costs and gait patterns of walking and running at self-selected, comfortable speeds in males and females. Total oxygen consumption was used to determine the metabolic cost, and cinematographic analysis was used to study the gait patterns of walking and running a distance of 1 km in 12 male and 12 female subjects. No significant sex difference was observed for the speed, vertical lift per stride, and total vertical lift per km of distance walked. Females ran at a significantly slower speed than males (P less than .01), but no significant sex difference was observed for the vertical lift per stride or total vertical lift per km of distance run. In both sexes, the gross and net energy costs of running were significantly greater (P less than .001) than those of walking when values were expressed as kcal . kg-1 . km-1 or cal . kg-1 . stride-1. No significant sex difference was observed in the gross or net metabolic cost of walking, whereas during running, the gross and net metabolic costs in kcal . kg-1 . km-1 were significantly higher (P less than .05) in females than in males. It was hypothesized that this sex difference was due to the cumulative effect of several factors which were biomechanical and metabolic in nature.

3. Bransford DR & Howley ET (1977): Oxygen cost of running in trained and untrained men and women. Med. Sci. Sports Exerc. 9, 4 1 -44.

The purpose of this study was to compare the oxygen cost of running as it relates to speed of running among the following four groups: trained male distance runners, trained female distance runners, untrained but active men and women. Each subject was given a series of treadmill tests during which Vo2 was measured at submaximal work loads. The linear regression equation was utilized to compute the relationship between Vo2 and running speed for each groups. The results indicated that the rate of increase in Vo2 for a given increase in running speed could be represented as a straight line and was the same for all groups (P greater than .05). The trained male runners had a significantly lower Vo2 (P less than .05) than those of the other three groups at any measured speed. The trained females and untrained males had significantly lower Vo2s than the untrained females (P less than .05) at any of the given range of speeds. No significant differences were observed between the untrained mean and trained women (P greater than .05). It was concluded that there were differences in the oxygen cost of running not only between the trained and untrained groups but also between males and females.

4. Brehm BA & Gutin B (1986): Recovery energy expenditure for steady state exercise in runners and nonexercisers. Med.Sci.Sport Exerc. 18, 205-210.

This study examined the effects of intensity, mode of exercise, and aerobic fitness on the energy expended during recovery (recovery oxygen consumption, or rec VO2 following steady state exercise. Eight runners (4 males, 4 females; 22-32 yr) walked at 3.2 and 6.4 km X h-1 and ran at 8.1 and 11.3 km X h-1 (18, 33, 50, and 68% peak VO2 All subjects completed 3.2 km of walking or running each session. Eight sedentary adults (4 male, 4 female; 21-33 yr) completed the 6.4 km X h-1 test. For the runners, net rec VO2 for 3.2, 6.4, 8.1 and 11.3 km X h-1 exercise was (X +/-SE) 12.52 +/- 3.00, 29.53 +/- 5.41, 28.64 +/- 2.91, and 44.27 +/-5.32 ml X kg-1, respectively, for the recovery period (18-48 min). Differences among group means were significant (P less than 0.05), except between 6.4 and 8.1 km X h-1 walking (29.53 +/-5.41 and 35.09 +/- 9.39 ml X kg-1). Statements attributing substantial energy expenditure to the recovery period may be misleading to people exercising at levels similar to those described in this study, since the recovery energy expenditure only amounted to approximately 13-71 KJ (3-17 kcal).

5. Bunc V & Heller J (1989): Energy cost of running in similarly trained men and women. Eur.J.Appl.Physiol 59, 178-183.

Physical Culture Research Institute, Charles University, Prague 1, Czechoslovakia. The energy demand of running on a treadmill was studied in different groups of trained athletes of both sexes. We have not found any significant differences in the net energy cost (C) during running (expressed in J.kg-1.m-1) between similarly trained groups of men and women. For men and women respectively in adult middle distance runners C = 3.57 +/- 0.15 and 3.65 +/-0.20, in adult long-distance runners C = 3.63 +/- 0.18 and 3.70 +/- 0.21, in adult canoeists C = 3.82 +/- 0.34 and 3.80 +/- 0.24, in young middle-distance runners C = 3.84 +/- 0.18 and 3.78 +/-0.26 and in young long-distance runners C = 3.85 +/- 0.12 and 3.80 +/- 0.24. This similarity may be explained by the similar training states of both sexes, resulting from the intense training which did not differ in its relative intensity and frequency between the groups of men and women. A negative relationship was found between the energy cost of running and maximal oxygen uptake VO2max expressed relative to body weight (for men r = -0.471, p less than 0.001; for women r = 0.589, p less than 0.001). In contrast, no significant relationship was found in either sex between the energy cost of running and VO2max We conclude therefore that differences in sports performance between similarly trained men and women are related to differences in VO2max.kg-1. The evaluation of C as an additional characteristic during laboratory tests may help us to ascertain, along with other parameters, not only the effectiveness of the training procedure, but also to evaluate the technique performed.

6. Bunc V, Heller J. Sprynarova S & Leso J (1988): Relationship between energy expenditure and running speed in laboratory. In: Exercise physiology: current selected research. edited by C.O. Dotson, et al, pp. 121-131. AMS Press, Inc. New York.

Running on the treadmill is one of the most often used means for determining functional capacity and/or fitness in the laboratory. It is possible to assume that the degree of mechanical and metabolic adaptation to this work load would be mostly marked according to its biomechanical similarity to walking. The energy output for running expressed indirectly by oxygen uptake per kg body weight (VO2/kg) can be calculated from the velocity of running (v) with the help of various monographs or equations. These relationships are linear in the range of submaximal work loads, approximately in range 20-90% of maximal aerobic power VO2max The relationship between VO2/kg and running speed are influenced by the degree of training, i.e. adapting to this work load (which changes mostly the mechanical efficiency) and also by sex and natural talent for running. On the basis of our measurements on the treadmill in differently trained athletes (long-distance runners, middle distance runners of both sexes and cross-country skiers) and untrained persons of middle age, supplemented by data from other authors, it was possible to demonstrate these relationships in a range limited on the bottom by an equation VO2(kg/ml)=2.950.v(km/h)+2.000, and the top by the equation VO2(kg/ml)=2.800.v(km/h)+14.000. An equation independent on training state was established for women: VO2(kg/ml)=2.756.v(km/h)+8.516, with maximal error about 10%, and a similar equation for men VO2(kg/ml)=3.1154.v(km/h)+3.886 with the same error. Finally, a general equation was established for the relationship between energy output and running speed on the treadmill: VO2(kg/ml)=2.875.v(km/h)+8.000, with a maximal error about 12%. These equations can be used for the running with a speed lower than 13 km/in even under field conditions, e.g. for doing daily or weekly exercise, For increasing energy output above a certain level so as to improve fitness or reduce body weight, etc.

7. Butts NK, Dodge C & McAlpine M (1993): Effect of stepping rate on energy costs during StairMaster exercise. Med. Sci. Sports Exerc. 25, 378-382 .

Human Performance Laboratory, University of Wisconsin-LaCrosse, Wl 54601. The responses to a self-selected stepping pattern (random) on a StairMaster 4000PT were compared with those obtained in response to the rates established by the manufacturer (cadence) in men (N = 14) and women (N = 14). During the random test the subjects stepped at their own natural, self-selected rate and distance. In cadence trial the subjects were required to step in time with a metronome at predetermined rates of 60, 77, 95, and 112 steps.min-1. Each trial consisted of four, 5-min continuous workloads during which HRs were recorded and expired air was analyzed using an automated open-circuit gas system each minute. All size dependent variables (i.e., VE and (O2.min-1) as well as relative VO2 (mlO2.kg-1.min-1) were significantly (P < 0.01) higher for the men across all stages and between methods. Although the random test produced slightly higher oxygen consumption values than the cadence trial, these differences were not significant (P > 0.05). The actual METs were significantly (P < 0.01) higher at all stages except at the lowest stepping rate for both methods compared with those estimated by the manufacturer. Equations were established to estimate actual MET costs: Men's METs = 2.675 + 0.935 (rate); women's METs = 2.934 + 0.817 (rate). Cross-validations of 0.975 and ().957 were obtained on an additional group of men (N = 8) and women (N = 11), respectively.

8. Butts NK, Knox KM & Foley TS (1995): Energy costs of walking on a dual-action treadmill in men and women. Med.Sci.Sport Exerc. 27,121-125.

Department of Exercise and Sports Science, University of Wisconsin--LaCrosse 54601. The physiological responses of normal walking and walking on a dual action treadmill which incorporates arm exercise were compared in 29 men and 37 women. Subjects completed six, 5-min steady-state exercises at 2.0, 3.0, and 4.0 mph (0.89, 1.34, 1.79 m.s-1) and 3% incline with and without arms. Estimated METs calculated according to the ACSM equations were compared with the actual METs. The men's ventilation (VE), and VO2 (I.min-1, ml.kg-1.min-1, and METs) were significantly (P < 0.001) higher at all speeds and for both conditions than the women's. There were no gender differences (P > 0.05) in heart rates (HR), respiratory exchange ratio, and ratings of perceived exertion (RPE) for each condition. The arm conditions yielded significantly (P < 0.001) higher responses at each speed for VE, l.min-1, ml.kg-1.min-1, METs, RPE, and HR. Although there were no significant (P < 0.05) differences in HR between men and women for each condition, the relationships between ml.kg-1.min-1 and HR differed. The actual METs obtained during the arm conditions were significantly (P < 0.05) higher than those estimated for both the men and women at all speeds. It was concluded that using the arms while walking on a dual action treadmill increases the energy costs an average of 55% above normal walking.

9. Carroll MW, Otto RM & Wygand J (1991): The metabolic cost of two ranges of arm position height with and without hand weights during low impact aerobic dance. Res.Q.Exerc.Sport, 62, 420-423.

Human Performance Lab, Adelphi University, Garden City, NY 11530. To determine the energy cost of low impact aerobic dance while varying arm movement height and the use of hand weights, 10 adults volunteered to participate in four choreographed trials. All trials consisted of identical leg movements. Arm movements, however, were performed above shoulder level both with and without 0.9-kg hand weights and below shoulder level both with and without 0.9-kg hand weights. Open circuit spirometry was employed throughout the 10-min videotape guided trials, and heart rate was measured by telemetry. Neither the use of hand weights nor the change in arm position height significantly altered the energy cost of low impact aerobic dance. However, heart rate responses were significantly different.. Caution should be observed by aerobics instructors and participants as to the use of heart rate as an indicator of intensity for low impact aerobic dance.

10. Cassady SL & Nielsen DH (1992): Cardiorespiratory responses of healthy subjects to calisthenics performed on land versus in water. Phys. Ther. 72, 532-538.

Physical Therapy Graduate Program, College of Medicine, University of , lowa City 52242. This study evaluated the oxygen consumption (VO2) and heart rate response curves for standardized upper- and lower-extremity exercise on land and in water. Forty healthy subjects performed one upper-extremity and one lower-extremity exercise at three selected cadences on land and in water. Steady-state heart rate was determined by electrocardiographic radiotelemetry and expressed as a percentage of age-predicted maximal heart rate (% APMHR). Percentage of age-predicted maximal heart rate was used as the criterion measure of relative exercise intensity. Oxygen consumption was determined by the open-circuit method. Results indicated systematic increases in VO2 from 2 to 9 metabolic equivalents (METs) (1 MET = 3.5 mL 02.kg-1.min-1) and % APMHR from 45% to 73% with increased cadence. The VO2 responses were highest during water exercise, whereas % APMHR was greater during land exercise. Based on the magnitude of the responses, water calisthenics appear to be of sufficient intensity to elicit training adaptations. Training studies are needed to document these changes.

11. Claremont AD & Hall SJ (1988): Effects of extremity loading upon energy expenditure and running mechanics. Med.Sci.Sport Exerc. 20, 167-171.

College of Health and Physical Education, Oregon State University, Corvallis 97331-6801. Physiological and mechanical consequences of running with commercially available hand and/or ankle weights were examined. Five males and three females (age 30 to 56 yr) ran for 30 min on a treadmill (0% grade) at a self-selected pace (8.9 to 13.7 km.h- 1), under randomized conditions of: (i) unloaded weights; (ii) hand weights; (iii) ankle weights; and (iv) hand + ankle weights. Respiratory gas exchange determinations, heart rates, and sagittal view film clips were obtained at selected time intervals. Highest energy expenditures and heart values were obtained for the fully loaded condition, with intermediate values measured for independent hand- and ankle-weighted trials. increased energy expenditure due to loading ranged from 5 to 8%. Lower extremity kinematics were unaffected by loading. Angular velocity and excursion of the arm segments was significantly (P less than 0.05) reduced when hand weights alone were carried. The results indicate that commercial claims of marked increases in energy expenditure during running with hand/ankle weights are exaggerated. It appears that the small actual increases in energy expenditure, the potential for increased impact forces, and the relative discomfort of carrying weights discredit running with hand and/or ankle weights as a desirable exercise alternative.

12. Cotes JE (1969): Relationships of oxygen consumption, ventilation and cardiac frequency to body weight during standardized submaximal exercise in normal subjects. Ergonomics, 12, 415427.

In normal males during submaximal exercise at a constant rate of external work on a bicycle ergometer or step test, the oxygen uptake and ventilation are linear functions of body weight. In normal females the oxygen uptakes do not differ materially from those for males of comparable weight. However, because of the constant terms in the regression equations, the convention of expressing results per kg body weight or m² body surface area may give rise to error; for ventilation this may be avoided by the use of the regression on oxygen uptake. Alternatively, the results may be reported at a constant oxygen uptake, for example, for men 1.5 I/min as recommended by l.L.O. and for women 1.0 I/min; the ventilation is then independent of body weight. By this procedure allowance is also made for differences in oxygen uptake due to the effects of practice. For the cardiac frequency a similar adjustment to a constant oxygen uptake yields values which are negatively correlated with body weight for walking on a treadmill, but not, in this instance, for standardized stepping and cycling.

13. Dal Monte A, Lupo S. Seriacopi D & Pigozzi F (1989): Energy consumption during passive isokinetic exercises. J.Sports Med.Phys.Fitness, 29, 123-128.

The energy cost and intensity of contractile muscle action incurred during passive gymnastics exercises in men and women was assessed and compared to other forms of activity. A polyfunctional isokinetic ergometer was used, which allowed tests to be performed at a constant predetermined speed and to be continued over time while the quantity of strength applied could be measured. Energy costs were determined from measuremenents of oxygen consumption made using a new telemetric system, K2 COSMED. Two groups of tests were conducted of the upper and lower limbs. The mean energy consumption of the upper limb exercises were 0.22 and 0.12 cal/kg/hr in men and women respectively, and of lower limb exercises were 0.78 and 1.39 cal/kg/hr in men and women respectively. These values are lower than those for other professional and common activities. Cardiac activity was modest and increases in heart rate were not significant. Although this type of exercise enables a passive mobilization of the joints which may be efficacious in certain situations, it is concluded that this type of exercise does not offer much assistance to those hoping to lose weight. [not original abstract]

14. Evans WJ, Winsmann FR, Pandolf KB & Goldman RF (1980): Self-paced hard work comparing men and women. Ergonomics, 23, 613-621.

Six fit male subjects (23 years, 171 cm, 67 kg, maximal VO2=2.25 mmol.kg-1.min-1 (50.3 ml.kg1.min-1) and six fit female subjects (22 years, 163 cm, 57 kg, maximal VO2=1.83 mmol.kg1.min-1 (41.1 ml.kg-1.min-1) performed self-paced hard work while walking over four different terrains carrying no external load, 10 kg and 20 kg. Time on each course for individual subjects was used to determine speed and energy expenditure; heart rate was recorded as each subject completed each course. Walking speed and energy expenditure of the males were found to be significantly greater (p<0.05) than those of the females over all terrains (blacktop road, 1.6 km; dirt road, 1.8 km; light brush, 1.4 km; and heavy brush, 1.3 km) and for each load carriage condition. Relative energy expenditures of the males and females for all conditions were very similar (p>0.05) and remarkably constant at a value close to 45% VO2max These data indicate that the voluntary hard work rate is dependent upon maximal aerobic power. The best predictor of speed for self-paced hard work of males and females for 1 to 2 hours in duration appears to be based on 45% of maximal aerobic power.

15. Gehlsen GM & Dill DB (1977): Comparative performance of men and women in grade walking. Hum.Biol. 49, 381-388.

In various studies of the energy expended by males and females in level and grade walking some report females require less energy per kg of body weight than males, but others report equality of the sexes in this respect. In this study the possible influences on energy cost of differences in age or in height or in weight were eliminated. Twelve males and twelve females were selected to yield two groups having the same means of age, height and weight. Despite these uniformities, there were significant differences in that females had longer legs and lower oxygen consumption when resting and when walking at 80 meters per minute on a 7% grade. The difference between males and females in oxygen consumption in the grade walk was only 3.6%, this was accounted for almost entirely by the females' lower resting energy consumption. After subtracting the resting oxygen consumptions from the oxygen consumptions in the grade walk, the net values in liters per minute were 1.20 for females and 1.22 for males: not significantly different.

16. Geissler CA, Dzumbira TM & Noor Ml (1986): Validation of a field technique for the measurement of energy expenditure: factorial method versus continuous respirometry. Am.J.Clin.Nutr. 44, 596-602.

The field technique for measuring daily energy expenditure, using activity diary plus short-term indirect calorimetry, was validated with a room respirometer. Eleven male and 14 female subjects spent 24-h periods in the respirometer and kept an activity diary to the nearest minute. Subsequently, the energy cost of the recorded activities was measured in duplicate, and 24-h expenditure was calculated. Over the 42 24-h measurements the mean value by the factorial field method was within 1% of that from continuous indirect calorimetry. However, the error in individual daily expenditure ranged from -17% to +25%. Correction of the error involved in using calculated BMR for the cost of sleeping resulted in a 5% mean underestimation of the daily value. The factorial method is, therefore, too inaccurate for the estimation of individual daily expenditures but provides a close estimate of the true energy expenditure for population groups.

17. Hagan RD, Strathman T. Strathman L & Gettman LR (1980): Oxygen uptake and energy expenditure during horizontal treadmill running. .J.Appl.Physiol 49, 571-575.

The purpose of this investigation was to compare linear and curvilinear regression equations relating oxygen uptake and energy expenditure to running velocity and to examine the effects of age, sex, and maximal aerobic power on these relations in well-conditioned male and female runners. One-variable linear equations that use running velocity as the independent variable for predicting oxygen uptake and energy expenditure and coefficients of determination (r2) of 0.86 and 0.897, respectively. Two-variable linear equations that use body mass and velocity as independent variables had r2 values of 0.895 and 0.901 for the same relation. Age, sex, and maximal aerobic power did not influence the relations between oxygen uptake, energy expenditure, and running velocity. Stepwise regression indicated that the two-variable linear equations had the highest r2 values suggesting that between the running velocities of 8.8 and 16.9 km.h-1 these equations best express the relation of oxygen uptake and energy expenditure to running velocity.

18. Hagerman FC, Lawrence RA & Mansfield MC (1988): A comparison of energy expenditure during rowing and cycling ergometry. Med.Sci.Sport Exerc. 20, 479-488.

Department of Zoological and Biomedical Sciences, Ohio University, Athens 45701. Metabolic and cardiorespiratory responses of healthy adults were compared at similar incremental power outputs during a variable-resistance rowing exercise and a fixed-resistance cycle ergometer exercise. Repeated measurements of power (watts), VEBTPS, VO2 STPD, and HR were obtained on 60 men and 47 women ranging in age from 20 to 74 yr. Average maximal power output for the men was significantly higher (P less than 0.05) for cycling than rowing: 207 +/- 5.2 W vs 195 +/58 W (mean +/- SE:). A similar difference was also observed for women favoring cycling: 135 +/4.1 W vs 126 +/- 4.9 W (mean +/- SE). VEBTPS, VO2 STPD, and HR were significantly higher at all power increments during the rowing graded exercise test (RGXT) when compared with the same exercise intensity during the cycle graded exercise test (CGXT). Consistent linearity was found between VEBTPS and VO2 STPD and between HR and VO2 STPD for both exercises. The linear relationship between VEBTPS and VO2 STPD for men during RGXT was r = 0.976, P less than 0.001, slope = 44.6 +/- 1.03, and for women during RGXT it was r = 0.990, P less than 0.001, slope = 19.6 +/- 0.36. The relationship between HR and VO2 STPD for men during rowing was r = 0.989, P less than 0.001, slope = 29.1 +/- 0.76, and for women during rowing it was r = 0.971, P less than 0.001, slope = 35.7 +/- 0.89. The linear relationship between VEBTPS and VO2 STPD for men during CGXT was r = 0.991, P less than 0.001, slope = 31.1 +/- ().98, and for women it was r = 0.959, P less than 0.991, slope = 29.6 +/- 0.87. The relationship between HR and VO2 STPD for men during CGXT was r = 0.997, P less than 0.001, slope - 28.1 +/- 0.83, and for women it was r = 0.990, R less than 0.001, slope = 35.9 +/- 0.96. Results indicated that energy costs for rowing ergometry were significantly higher than cycle ergometry at all comparative power outputs including maximum levels. It was concluded that rowing ergometry could be an effective alternative activity for physical fitness and exercise rehabilitation programs.

19. Haymes EM & Byrnes WC (1993): Walking and running energy expenditure estimated by Caltrac and indirect calorimetry. Med.Sci.Sport Exerc. 25, 1365-1369.

The purpose of this study was to examine the accuracy of the Caltrac personal activity computer during walking and running. Ten women and 10 men walked at speeds of 2-5 mph and ran at speeds of 4-8 mph on a horizontal treadmill. Two Caltrac monitors were attached over opposite hips: one programmed to give caloric expenditure and the other to give Caltrac counts. Oxygen uptake was measured simultaneously. Significant correlations were found during walking between Caltrac estimated and actual expenditure (r=0.91) and between activity counts and net exercise VO2.kg^-1 (r=0.87). However, the Caltrac significantly overestimated energy cost during horizontal walking at speeds above 2 mph. Although there was a significant correlation between Caltrac estimated and actual expenditure during running (r=0.71), the correlation between Caltrac counts and net exercise VO2.kg^-1 was not significant (r=.29). There was no significant increase in Caltrac kcal or counts with increased running speed between 5 and 8 mph. It is concluded that the Caltrac is a valid indicator of physical activity during walking, but does not adequately discriminate between running speeds of 5-8 mph.

20. Holewijn M, Heus R & Wammes LJA (1992): Physiological strain due to load carrying in heavy footwear. Eur.J.Appl.Physiol 65,129-134.

TNO Institute for Perception, Thermal Physiology Research Group, Soesterberg, The Netherlands. To determine the effects of wearing heavy footwear on physiological responses five male and five female subjects were measured while walking on a treadmill (4, 5.25, and 6.5 km.h1) with different external loads (barefooted, combat boots, and waist pack). While walking without an external load the oxygen uptake, as a percentage of maximal oxygen uptake (%VO2max) of the men increased from 25% VO2max at 4 km.h-1 to 31% VO2max at 5.25 km.h-1 and to 42% VO2max at 6.5 km.h-1. The women had a significantly higher oxygen uptake of 30%, 40%, and 55% VO2max, respectively. In the most strenuous condition, walking at 6.5 km.h-1 with combat boots and waist pack (12 kg), the oxygen uptake for the men and women amounted to 53% and 75% VO2max respectively. The heart rate showed a similar response to the oxygen uptake, the women having a heart rate which was 15-40 beats.min-1 higher than that of the men, depending on the experimental condition. The perceived exertion was shown to be greatly dependent on the oxygen uptake. From the results a regression formula was calculated predicting the oxygen uptake depending on the mass of the footwear, walking speed and body mass. It was concluded that the mass of footwear resulted in an increase in the energy expenditure which was a factor 1.9-4.7 times greater than that of a kilogram of body mass, depending on sex and walking speed.

21. Holmer I (1972): Oxygen uptake during swimming in man. .J.Appl.Physiol 33, 502-509.

It is possible to set the water flow rate with great accuracy in a recently constructed swimming flume, i.e., a kind of swimming "treadmill". Oxygen uptake, heart rate, and blood lactate concentrations were measured in three female and six male adult subject, with varying proficiency in swimming, while subjects swam three styles at different speeds. The same determinations were made during exercise on a Krogh bicycle ergometer and on a treadmill. The same determinations were made in 12 girl swimmers, 13-18 years old, but only during maximal running and maximal swimming. Minimal oxygen uptake during floating in a vertical position in nine subjects varied from 0.9 to 2.0 I.min^-1. At a given swimming speed the trained swimmers were able to swim with a much lower oxygen uptake than subjects who were not trained swimmers. At a given oxygen uptake trained swimmers also swam much faster than the untrained swimmers. The front crawl proved to be the most economical style, as is the case in competition swimming. The back crawl was somewhat less economical and the breaststroke was the least economical style. Maximal oxygen uptake, maximal pulmonary ventilation, and maximal heart rate were significantly lower in swimming than in running or cycling, respectively.

22. Howley ET & Glover ME (1974): The caloric costs of running and walking one mile for men and women. Med.Sci.Sport Exerc. 6, 235-237.

Our purpose was to resolve the disagreement as to the number of calories expended per unit distance for walking and running. The caloric costs of walking and running one mile on a treadmill were calculated for eight men and eight women. The subjects walked at a speed of 82 +3 m/min (X+- SD) and ran at a speed that was regarded subjectively as comfortable. The average speed at which the mile was run was 195 +- 25 m/min for men and 137 +- 4 m/min for women. The average R measured during the walk was 0.86 and during the run 0.96. The gross caloric cost of walking was 1.08 +- 0.06 kcal/kg per mile for men and 1.15 +-0.08 kcal/kg per mile for women, and the cost of running was 1.57 +- 0.09 kcal/kg per mile for men and 1.73 +0.09 kcal/kg per mile for women. The running required significantly more kcal/kg per mile than walking (P<0.001) and the women used significantly more calories for both running and walking compared to the men (P<0.01). The net caloric cost of walking was 0.76 +- 0.07 kcal/kg per mile for men and 0.83 +- 0.08 kcal/kg per mile for women, and the cost of running was 1.43 +-0.08 kcal/kg per mile for men and 1.53 +- 0.09 kcal/kg per mile for women. The difference between the run and walk was highly significant (P<0.001) and the women used significantly more calories than men for both activities (P<0.05). Possible reasons for the small but statistically significant difference between men and women are discussed. It was concluded that running a given distance required more calories than walking the same distance.

23. Johnson BL, Stromme SB, Adamczyk JW & Tennoe KO (1977): Comparison of oxygen uptake and heart rate during exercises on land and in water. Phys. Ther. 57, 273-278.

Oxygen comsumption and heart rate response during identical calisthenic-type exercises performed on land and in the water were compared in eight subjects. Both the heart rate and the oxygen uptake were greater during exercises in water. Although gravity is the primary resistance to movement on land, viscosity friction and turbulence are dominant resistive factors in the water. The results of this study indicate that the latter two factors provide a greater load during exercise than the resistance of gravity in land exercises. At a moderate rhythm of leg exercises, oxygen consumption increased about ten times over resting values in the water for :men subjects and about seven times for women. Arm exercise performed in the water require less energy than leg exercises in water, but arm exercises require significantly more oxygen when performed in water than the same exercises performed on land.

24. Katch VL, Villanacci JF & Sady SP (1981): Energy cost of rebound-running. Res.Q.Exerc.Sport, 52, 269-272.

The purpose of this study was to examine the energy cost and heart rate response of rebound-running on a mini trampoline and to make comparisons with other forms of aerobic exercise. Twelve volunteers were selected who varied in age, sex, weight and height. Oxygen consumption was measured in steady-state exercise conditions by open circuit respirometry. Subjects breathed through a Collins triple J respiratory valve into metereological balloons and the contents were analysed immediately. Gas analyzers were calibrated before and after each test. Oxygen uptake was calculated according to the method of Conzolazio et al (1963) and calorie expenditures calculated using the standard conversion for the calorific equivalent per liter of oxygen at a given respiratory exchange ratio, assuming steady-rate exercise conditions. The average VO2 for men and women combined was 1.21 I.min-1, which places rebound-running in the "moderate" exercise category, and the average calorie expenditure was 0.0864 kcal.kg-1.min-1. [not original abstract]

25. Kumar S (1984): The physiological cost of three different methods of lifting in sagittal and lateral planes. Ergonomics, 27, 425-433.

Twelve young adults (six males-mean age 24.1 years, mean weight 75.4 kg and mean height 176.6 cm- and six females- mean age 20 years, mean weight 59.8 kg and mean height 162.6 cm) lifted and lowered a weight of 10 kg from a height of 13.5 cm at three-quarters reach. The weight was lifted and lowered in the! sagittal 30° lateral and 60° lateral plane by stoop, squat and freestyle techniques six times per minute for a period of 4 min. and the subjects rested for a period of 10 min. The steady-state values of oxygen consumption during these activities were measured. The subjects also subjectively assessed the relative degree of tiresomeness of the tasks studied. The oxygen consumption for each of the techniques was significantly different from the others (p<0.01). The stoop method of lifting required the least amount of oxygen and had the lowest per-minute inspiratory ventilation volume. The squat method required the highest oxygen consumption and inspiratory ventilation volume. The plane of the activities did not have a statistically significant effect on the energy consumption. The squat method of lifting was subjectively rated most tiring, and free style least tiring of the three techniques studied.

26. Kurzer MS (1987): Effect of activity on the energy cost of sitting in men and women: implications for calorimeter studies. Hum.Nutr.Clin.Nutr. 41C, 403-407.

It is important that activities be carefully standardized during whole-body human calorimetry studies because differences in physical activity in the calorimeter between subjects may mask true metabolic differences or result in false differences. The purpose of this study was to quantify the extra heat losses that: may occur due to small body movements, which are not standardized while sitting in whole-body calorimetry activity programmes. Energy expenditure was measured in 17 men and women while sitting passively and sitting actively. The subjects sat in a chair in a whole-body calorimeter for a total of 4 hours. During the first hour the subjects sat and were allowed to read and listen to the radio while adapting to the calorimeter. During the second and fourth hour the subjects sat passively, and during the third hour they performed standardized arm and leg stretches every 6 minutes while remaining seated. A 31 % increase in total heat loss during active sitting was found. It is thus important that the manner of sitting be controlled in studies looking for an effect smaller than 15%.

27. Makalous SL, Araujo J & Thomas TR (1988): Energy expenditure during walking with hand weights. Physician Sportsmed. 16, 139-148.

Eleven obese adults (three men, eight women) performed three 30-minute walking sessions at 3.4 mph: normal walking, walking with increased arm movement, and walking with increased arm movement while holding hand weights. The purpose was to assess the additional energy expenditure induced by carrying hand weights. Walking with hand weights resulted in increased heart rate (127 vs 120 beats.min^-1), increased VO2 (1.168 vs 1.086 L.min^-1), and greater energy expenditure (171.5 vs 159.7 kcal) compared with normal walking. Fat use and recovery energy expenditures were similar in all exercise conditions. Increased arm movements while walking without weights resulted in no significant increases over normal walking. These results indicate that using hand weights increased the energy demands of walking, but only to a small degree.

28. Maughan RJ & Leiper JB (1983): Aerobic capacity and fractional utilisation of aerobic capacity in elite and non-elite male and female marathon runners. Eur.J.Appl.Physiol 52, 80-87. The physiology of marathon running has been extensively studied both in the laboratory and in the field, but these investigations have been confined to elite competitors. In the present study 28 competitors who took part in a marathon race (42.2 km) have been studied; 18 male subjects recorded times from 2 h 19 min 58 s to 4 h 53 min 23 s; 10 female subjects recorded times between 2 h 53 min 4 s and 5 h 16 min 1 s. Subjects visited the laboratory 2-3 weeks after the race and ran on a motor driven treadmill at a series of speeds and inclines; oxygen uptake VO2 was measured during running at average marathon racing pace. Maximum oxygen uptake VO2 max) was measured during uphill running. For both males (r = 0.88) and females (r = 0.63), linear relationships were found to exist between marathon performance and aerobic capacity. Similarly, the fraction of VO2 max which was sustained throughout the race was significantly correlated with performance for both male (r = 0.74) and female (r = 0.73) runners. The fastest runners were running at a speed requiring approximately 75% of VO2 maxi for the slowest runners, the work load corresponded to approximately 60% of VO2 max. Correction of these estimates for the additional effort involved in overcoming air resistance, and in running on uneven terrain will substantially increase the oxygen requirement for the faster runners, while having a much smaller effect on the work rate of the slowest competitors. Five minutes of treadmill running at average racing pace at zero gradient did not result in marked elevation of the blood lactate concentration in any of the subjects.

29. Mayhew JL, Piper FC & Etheridge GL (1979): Oxygen cost and energy requirement of running in trained and untrained males and females. J.Sports Med. 19, 39-44.

The oxygen cost and energy requirement of submaximal treadmill running was assessed on trained (n=1) males and trained (n=5) and untrained (n=6) females. Open circuit spirometry was used to determine each subject's oxygen consumption during the final 2 minutes of 5-minute runs at 135, 150, 165, and 180 m/mint Two-way ANOVA was used to determine differences across speeds and subjects. Submaximal VO2 (ml/kg/min) was not significantly different among the four groups. Trained subjects, however, showed slightly greater efficiency than their untrained counterparts (5%). The VO2-running speed relationships were linear for all groups. Regression slopes and intercepts were not significantly different. Untrained females expended significantly more relative energy (kcal/kg/km) than untrained males, but no more than the two trained groups. The reason for this was perhaps a combination of greater relative fat content and inefficient running mechanics of the untrained females.

30. Miller JF & Stamford BA (1987): Intensity and energy cost of weighted walking vs. running for men and women. J.Appl.Physiol. 62, 1497-1501.

The energy cost and intensity of exercise performed at 0% grade were determined for walking at 2, 3, and 4 mph, running at 5, 6, and 7 mph, and walking at 2, 3, and 4 mph with ankle and/or hand weights. Subjects were young moderately trained males (4) and females (3). The energy cost per kilogram of body weight was similar between sexes, and data were combined for among-treatment comparisons. Intensity of effort and energy cost per minute and per mile were increased when weight was added during walking and were increased more with hand weights compared with ankle weights regardless of speed. The average increase in 02 uptake (ml.kg^-1 .min^-1.100 g^-1 of added wt) was 0.8% for ankle, 1.3% for hand, and 0.9% for ankle and hand weights. Gross energy cost per mile during weighted walking (120-158 kcal/mile) was comparable to and in some cases exceeded that of running which was independent of speed (120-130 kcal/mile). During nonweighted walking, the energy cost (kcal/mile) was significantly greater at 4 mph compared with 2 and 3 mph which did not differ. The intensity of walking at 4 mph with ankle and hand weights was comparable to running at 5 mph.

31. Morrissey SJ, George CE & Ayoub MM (1985): Metabolic costs of stoopwalking and crawling. Appl.Ergon. 16, 99-102.

This paper is a study of the metabolic costs of crawling and stoopwalking as performed by trained male and female subjects. After training, male and female subjects crawled and stoopwalked at a range of task speeds and in task postures set at 100, 90, 80, 70 and 60% of each subject's erect stature. It was found that as the task posture became more stooped, or the task speed increased, there were marked increases in metabolic cost. Further analysis found these increases to be due to the task speed within a posture, rather than from the task posture. It was also found that in some task postures, the combination of speed and posture resulted in metabolic costs of performance which would be limiting in terms of non-fatigue task performance time.

32. Padilla S. Bourdin M, Barthelemy JC & Lacour JR (1992): Physiological correlates of middle-distance running performance. A comparative study between men and women. Eur.J.Appl. Physiol. 65, 561-566.

Centro Medicina Deportiva, Neudigonoza Amadeo Garcia Salazar S/U, Victoria-Gasteiz, Spain. To compare the relative contributions of their functional capacities to performance in relation to sex, two groups of middle-distance runners (24 men and 14 women) were selected on the basis of performances over 1500-m and 3000-m running races. To be selected for the study, the average running velocity (v) in relation to performances had to be superior to a percentage (90% for men and 88% for women) of the best French v achieved during the season by an athlete of the same sex. Maximal 02 consumption VO2max and energy cost of running (CR) were measured in the 2 months preceding the track season. This allowed us to calculate the maximal v that could be sustained under aerobic conditions, va,max. A v:va,max ratio derived from 1500-m to 3000-m races was used to calculate the maximal duration of a competitive race for which v = va,max (tva,max). In both groups va,max was correlated to v. The relationships calculated for each distance were similar in both sexes. The CR [0.179 (SD 0.010) ml.kg-1 x m-1 in the women versus 0.177 (SD 0.010) in the men] and tva,max [7.0 (SD 2.0) min versus 8.4 (SD 2.1)] also showed no difference. The relationships between VO2max and body mass (mb) calculated in the men and the women were different. At the same mb the women had a 10% lower CR than the men; their lower mb thus resulted in an identical CR. In both groups CR and VO2max were strongly correlated (r=0.74 and 0.75 respectively, P < 0.01), suggesting that a high level of VO2max could hardly be associated with a low CR. These relationships were different in the two groups (P < 0.05). At the same VO2max the men had a higher va,max than the women. Thus, the disparity in track performances between the two sexes could be attributed to VO2max and to VO2max/Cr relationships.

33. Ryschon TW & Stray-Gundersen J (1991): The effect of body position on the energy cost of cycling. Med.Sci.Sport Exerc. 23, 949-953.

Department of Internal Medicine, U.T. Southwestern Medical School, Dallas. Energy expenditure during bicycling on flat terrain depends predominantly on air resistance, which is a function of total frontal area (bicycle and rider), coefficient of drag, and air speed. Body position on the bicycle may affect energy expenditure by altering either frontal area or coefficient of drag. In this study, oxygen uptake (VO2) was measured for each of four body positions in 10 cyclists (8 males, 2 females, 24 +1-2 yr, 67.7 +/- 3.3 kg, VO2max = 65.8 +/- 1.5 ml.kg-1.min-1) while each bicycled up a 4% incline on a motor-driven treadmill (19.3 km.h- 1), thereby eliminating air resistance. Positions studied included: 1) seated, hands on brake hoods, cadence 80 rev.min-1; 2) seated, hands on dropped bar (drops), 80 rev.min-1; 3) standing, hands on brake hoods, 60 rev.min-1; and 4) seated, hands on brake hoods, 60 rev.min-1. Subjects rode their own bicycles, which were equipped with a common set of racing wheels. Energy expenditure, expressed as VO2 per unit combined weight, was not significantly different between drops and hoods positioning (30.2 +/- 0.6 vs 29.9 +/- 0.9 ml.kg-1.min-1) but was significantly greater for standing compared with seated cycling (31.7 +/- 0.4 vs 28.3 +/- 0.7 ml.kg-1.min.-1, P < 0.01). These results indicate that body posture can affect energy expenditure during uphill bicycling through factors unrelated to air resistance.

34. Ryschon TW & Stray-Gundersen J (1993): The effect of tyre pressure on the economy of cycling. Ergonomics, 36, 661-666.

Department of Internal Medicine, University of Texas, Southwestern Medical School, Dallas. Cycling requires power generation to overcome gravity, air resistance, and rolling resistance. When rolling surface and rolling speed are constant for a given tyre, rolling resistance is determined by tyre inflation pressure and the combined weight (COO) of the bicycle and rider. In this study, the oxygen uptake per unit CW (VO2.CW-1) of seven trained bicycle racers (5 men, 2 women, 24 +/- 2 years) was measured while each cycled up a 4% incline at 19.3 km.h-1 and 75 revolutions.min-1 on a motor-driven treadmill, using randomly-ordered tyre pressures of 552, 690, 827, and 965 kPa. Subjects (55.8-78.4 kg) rode their racing bicycles equipped with the same set of sew-up tyres and wheels. VO2.CW-1 was averaged over the last 3 min of a 5 min ride at each pressure. A repeated measures analysis of variance was performed and significance set at p c 0.05. VO2.CW-1 ranged from 28.1 +/- 0.6 to 28.9 +/- 0.5 ml.kg-1 x min-1 and was not significantly different between tyre pressures. We conclude that differences in rolling resistance caused by varying tyre pressure between 552 and 965 kPa are too small to be detected physiologically.

35. Schiller WR, Long CL, Carlo M, Davis D & Blakemore WS (1978): Energy costs of physical therapy in normal subjects. Fed.Proc. 37, 581.

Physical therapy is commonly administered to hospitalized convalescing patients, however, the energy demands for these treatments are not well known. Certain patients with marginal exercise tolerance may not tolerate exercises with high caloric expenditures. To quantitate the caloric expenditure of commonly utilized modes of physical therapy, 10 normal control volunteers were studied. The energy cost of these activities was determined by means of indirect calorimetry. The 02 consumption and the CO2 production were measured at, 1) resting levels, 2) during arm lifting of a 5 lb weight at 12 times per minute, and, 3) while doing straight leg raising at 6 times per minute for 12 minutes. The caloric expenditure for males at rest was 0.6107 ± .053 kcal/min/m² while for females was 0.6205 i .07 kcal/min/m². The values for arm lifting were 0.8169 ± .096 kcal/min/m² and 0.8052 + .0813 kcal/min/m² for females. This represented a 34% increase over resting values for males and 30% increase for females. When straight leg raising was performed, the caloric expenditure was 0.7973 i .076 kcal/min/m² for males and 0.8294 ± .099 kcal/min/m² for females. This represented a 31% for male and a 34% for female over resting values. In summary, these preliminary data show the energy cost of both activities to be slightly above that expended during standing as determined by a previous study to be 0.749 ± 0.12 kcal/min/m²

36. Seliger V (1968): Energy metabolism in selected physical exercises. Int.Z.angew.Physiol. einschl. Arbeitsphysiol. 25,104-120.

The energy costs of 15 physical activities were examined in 275 subjects under training conditions of the particular activity. The sample contains usually 15 medium athletically developed persons at minimum. The energy metabolism was followed by indirect calorimetrical method, the heart rate was registered throughout the experimental telemetrically. The activities were divided into three groups, according to the time of duration. The results showed that the energy expenditure ranges were in A-group (duration 5 min and more) 0.08-0.26 kcal/min/kg, in B-group (1-3 min) 0.11-0.45 kcal/min/kg, and in C-group (1-30 see) 0.68-1.75 kcal per min/kg. The observed values of heart rate, pulmonary ventilation, and oxygen uptake are discussed. No correlation between the energy expnditure and the intensity of the motional activity, according to pedagogues' observation was found. The relationship to physiological function was with respect to motional activity on 1-5% significance level, especially in sports from groups A and B. A graph was constructed of the relationship of the intensity of metabolism, against duration of the activity. Three fields limited by parallel lines enables us to judge the real metabolic rate during the sports' activity of examined persons to functional development of his organismus.

37. Snyder AC, O'Hagan KP, Clifford PS, Hoffman MD & Foster C (1993): Exercise responses to in-line skating: comparisons to running and cycling. Int.J.Sports Med. 14, 38-42.

Department of Human Kinetics, University of Wisconsin-Milwaukee 53201. A comparison of the physiological responses to in-line skating with the more traditional modes of exercise training has not been reported. The purpose of this study was to examine the physiological responses to in-line skating compared with running and cycling. Nine trained volunteers (2 male, 7 female) performed 3-6 submaximal (30-90% VO2max workloads with each exercise mode. Oxygen uptake, heart rate and blood lactate were measured during each trial. Across the spectrum of oxygen uptakes studied, heart rate was higher with in-line skating than with cycling or running. At a lactate concentration of 4 mM oxygen uptake was less for in-line skating and cycling than for running. Therefore, while in-line skating may be an effective mode of aerobic exercise, the training adaptations for in-line skating at 4 mM lactate may not be as great as for running, and at a given HR may be less than for running and cycling.

38. Stauffer RW, McCarter M, Campbell JL & Wheeler LF, Jr. (1987): Comparison of metabolic responses of United States Military Academy men and women in acute military load bearing. Aviat.Space Environ.Med. 58, 1047-1056.

Exercise Science Laboratory, United States Military Academy, West Point, New York 10996. Twenty-four first year United States Military Academy (USMA) men and women were studied to compare metabolic response differences in seven horizontal walking velocities, under three military load bearing conditions. The treadmill protocol consisted of walking or jogging on a horizontal treadmill surface for 3-min intervals at velocities of 3, 3.5, 4, 4.5, 5, 5.5, and 6 mph. The three military load bearing conditions weighed 5, 12, and 20 kg. Metabolic measurements taken at each speed in each of the military load bearing conditions were: minute volume, tidal volume, respiratory rate, absolute and relative to body weight oxygen consumption, and respiratory quotient. Two three-way analyses of variance for repeated measures tests with main effects of gender, military load, and speed revealed that USMA men and women metabolically respond to different military load bearing conditions; they metabolically respond to different walking and jogging velocities under military load bearing conditions; and they have identifiable and quantifiable metabolic response differences to military load bearing. This study was designed to improve USMA physical and military training programs by providing information to equally and uniformly administer the USMA Doctrine of Comparable Training to men and women alike; and additionally to clarify the "...minimal essential adjustments...required because of physiological differences between male and female individuals ..." portion of Public Law 94106 providing for the admission of women to America's Service Academies .

39. Town GP, Sol N & Sinning WE (1980): The effect of rope skipping rate on energy expenditure of males and females. Med.Sci.Sport Exerc. 12, 295-298.

The purpose was to study the effects of skipping rate on energy expenditure and sex differences in response to rope skipping. Responses of 19 males and 11 females were measured while skipping for 5 min at 125, 135 and 145 skips.min-1. Expired air was routed through a hollow handle to collection bags to provide uninterrupted exercise. Values at the respective rates for the total sample were: VO2 (I.min-1) 2.70, 2.83, 2.85; VO2 (ml.kg-1.min-1) 41.1, 42.0 42.5; HR (beats.min-1) 176, 177, 177; VE (I.min) 102.2, 103.5, 106.3; R 1.09, 1.07, 1.05; energy expenditure (kj.min-1) 58.6, 59.4, 60.3. Sex differences were found in that females had significantly lower VO2 both in l.min-1 and ml.kg-1.min-1 but higher HR values than males. Comparison of VO2 values of the females to VO2max values reported for females in the literature suggested that they may have been exercising close to their maximum. There were no differences in any of the values due to skipping rate nor was there interaction between sex and rate. Retrospective cinematographic analysis on two subjects suggested that the failure to find significant differences due to rate may be due to a decrease in vertical displacement resulting in a relatively constant work output as skipping rate increased. Average MET values at the different rates ranged from 11.7 to 12.5, which supported findings from other studies that rope skipping is very strenuous exercise.

40. Webb P. Saris WHM, Schoffelen PFM, van Ingen Schenau GJ & ten Hoor F (1988): The work of walking: a calorimetric study. Med.Sci.Sport Exerc. 20, 331-337.

Experiments were designed to test the traditional assumption that during level walking all the energy from oxidation of fuel appears as heat and no work is done. Work is force expressed through distance or energy transferred from man to the environment, but not as heat. While wearing a suit calorimeter in a respiration chamber, five women and five men walked for 70 to 90 min on a level treadmill at 2.5, 4.6 and 6.7 km.h^-1 and pedalled a cycle ergometer for 70 to 90 min against a horizontal load. During cycling, energy from fuel matched heat loss plus the power measured by the ergometer. During walking, however, energy from fuel exceeded that which appeared as heat, meaning that work was done. The power increased with walking speed; values were 14, 29 and 63 W. which represented 11, 12, and 13% of the incremental cost of fuel above the resting level. Vertical and horizontal loads increased the fuel cost and heat loss off walking but did not alter the power output. This work energy did not re-appear as thermal energy during 18 h of recovery. The most likely explanation of the work done is in the inter-action between the foot and the ground, such as compressing the heel of the shoe and bending the sole. We conclude that work is done in level walking.

4.5 Miscellaneous: women

1. Banerjee B. Khew KS, Saha N & Ratnam SS (1971): Energy cost and blood sugar level during different stages of labour and duration of labour in Asiatic women. J.Obstet.Gynaecol. Br.Commonw. 78, 927-929.

Forty-four Chinese women of mixed parity had their energy output measured on one occasion; 28 in the first stage and 16 in the second stage of labour. No difference in energy output was noticed with varying parity. The energy output in the second stage of labour was found to be 40 percent more than in the first stage. In another 39 women in different stages of labour who were not given sedatives, and 17 women who received 100 mg. pethidine in the second stage of labour, measurements of energy output, pulmonary ventilation, oxygen consumption and blood glucose were made during labour and after delivery. In women who were not given sedatives these values were found to be significantly higher in the second stage of labour than in the first stage and after delivery. The values were significantly lower in the sedated than in the unsedated women both during labour and after delivery. The blood glucose level was, however, found to be significantly higher in the sedated women than the unsedated women both during and after delivery.

2. Katz M, Kroll D, Shapiro Y. Cristal N & Meizner I (1990): Energy expenditure in normal labor. Isr.J.Med.Sci. 26, 254-257.

Division of Obstetrics and Gynecology, Soroka Medical Center, Beer Sheva, Israel. The energy expenditure in 23 healthy parturient women during spontaneous labor was assessed by continuous measurement of their 02 consumption and CO2 production. Due to the intermittent character of uterine contractions, normal labor and delivery did not impose high energy demands on the parturient, whereas a prolonged labor and delivery in which energy input was high led to maternal metabolic disturbances.

5. Elderly

1. Calloway DH & Zanni E (1980): Energy requirements and energy expenditure of elderly men. Am.J.Clin.Nutr. 33, 2088-2092.

Basal metabolic rates (BMR) and energy cost of a few activities were measured in healthy men aged 63 to 77 years who were participants in a study of protein requirements (previously reported). The men were confined to a metabolic unit for 47 days and received a defined formula diet. Their body weights were 8 to 19 kg higher than that of younger men of the same heights and their whole body potassium content was 12% less than that of younger men (average 28 years of age) studied in the same unit. BMR of the older men was 1622 +/- 189 kcal/day, a figure 13% below the per diem rate of younger men but the same per unit of body potassium. Energy cost of sedentary activities was related to BMR. Expenditure while Iying at rest was 1.22 X BMR and while sitting quietly, 1.30 X BMR; these values are the same as in younger men. Walking level at about 2.5 mph cost 4.51 +/-0.34 kcal/min (about 4 X BMR) and cycling at a comfortable load (300 to 400 kpm) only slightly more. Energy intake required to maintain body weight of these men, who were sedentary except for 30 min of cycling daily, was 2554 +/- 222 kcal/day, or about 1.6 X BMR. Minimum maintenance energy requirement (i.e., ambulatory but inactive) of healthy older men appears to be 1.5 X BMR, the same as in other age groups.

2. Didier JP, Mourey F. Brondel L, Marcer I, Milan C, Casillas JM, Verges B & Winsland JK (1993): The energetic cost of some daily activities: a comparison in a young and old population. Age Ageing, 22, 90-96.

Groupe d'Etude et de Recherche sur le Handicap, C.H.R.U. de Dijon, France. The energetic costs of some daily activities were compared in two groups, 10 young people (24.3 +/- 2.8 years) and 10 old people (74.4 +/- 2.2 years): rising and sitting back down on a seat, getting up from and Iying down on a bed and getting up from the floor. The oxygen consumption and the time necessary for the activities were measured. The results showed a noteworthy economical energetic procedure when rising and sitting back down on a seat among the older group. The values of the energy expenditure were respectively 3.9 +/- 1.3 car/kg in the older group and 5.8 +/- 1.6 in the younger one with a standard seat (45 cm) and 2.7 +/- 1.2 vs 5.2 +/- 1.5 with a raised seat (60 cm). The activities did not vary significantly in time in the two age groups. This procedure could be understood as an adaptation of the energy expenditure to the reduced aerobic capacity with ageing. Conversely, getting up from and Iying down on the floor or a standard hospital bed involved the same energy expenditure in the older and younger group, but performing these activities took significantly longer for the older people (+60% for getting up from the floor, +33% from the bed). As these activities revealed no economical energetic procedure in the older group, they appeared responsible for a strong factor of dependence. The importance of a learning process particularly for the most usual movements in everyday life is discussed.

3. Evans BW, Potteiger JA, Bray MC & Tuttle JL (1994): Metabolic and hemodynamic responses to walking with hand weights in older individuals. Med.Sci.Sport Exerc. 26, 10471052.

Department of Physical Education, Indiana State University, Terre Haute, USA. The purpose of this study was to examine metabolic and hemodynamic responses of older adults (age = 66.2 +/5.6 yr) to walking with hand-held weights (HHW). Nineteen volunteers participated in eight randomly assigned, 10-min, submaximal, self-selected constant speed (CSP) or constant heart rate (CHR) exercise bouts using the following HHW conditions: no weight, W0; 0.45 kg, W1; 1.36 kg, W3; 2.27 kg, W5. Oxygen uptake VO2 was recorded every 30 s, heart rate (HR) each minute, and blood pressure (BP) every 2 min. Mean values for the last 5 min of exercise were analyzed using repeated measures ANOVA. Contrast comparison tests were used to determine differences among means. During CS, significant differences between means (P < or = 0.05) existed for: VO2 (W0, W1 < W3, W5); HR, SBP, DBP, SBPmax, DBPmax (W0 < W1, W3, W5); HR, rate pressure product (RPP), DBPmax (W1 < W5); SBP, DBP, SBPmax, RPP (W3 < W5). During CHR, significant differences (P < or = 0.05) between means existed for: SBP, DBP, RPP (W0, W1, W3 c W5); DBP (W0 < W3; W1, W3 < W5). These results indicate that the use of HHW significantly increases metabolic responses at W3 and W5 during CS exercise in older adults, while hemodynamic responses increase significantly across HHW for both CS and CHR. Due to the increases in hemodynamic responses, the use of HHW may be contraindicated for older individuals with suspected or diagnosed cardiovascular disease.

4. Treuth MS, Hunter GR, Weinsier RL & Kell SH (1995): Energy expenditure and substrate utilization in older women after strength training: 24-h calorimeter results. .J.Appl.Physiol 78, 2140-2146.

Department of Nutrition Science, University of Alabama at Birmingham, 35294-3360, USA. The purpose of this study was to examine the effects of strength training (ST) in healthy older women on 24-h energy expenditure (EE) and its components and on 24-h substrate utilization. Thirteen women (age 67 +/- 1 yr) exercised three times per week for 16 wk in a total body ST program. EE components and substrate utilization were determined for 24 h in an indirect room calorimeter before and after training. The ST invoked a 47% increase in upper body and a 66% increase in lower body strength (P < 0.001). Body weight, percent body fat, and fat-free mass did not change significantly; however, midthigh muscle area increased (55.2 +/- 3.1 vs. 60.4 +/2.3 cm2; P < 0.05). There is a significant increase in resting EE (5,017 +/- 218 vs. 5,473 +/- 213 kJ/day; P < 0.05) but no significant changes in sleeping EE (4,929 +/- 180 vs. 5,067 +/- 251 kJ/day), diet-induced thermogenesis (359 +/- 25 vs. 393 +/- 33 kJ/day), activity EE (682 +/- 84 vs. 381 +/117 kJ/day), or 24-h EE (6, 054 +/- 188 vs. 6,247 +/- 243 kJ/day). The increase in resting EE is not significant after the increase in muscle area is taken into account. The 24-h nonprotein respiratory quotient decreased (0.90 +/- 0.01 vs. 0.82 +/- 0.01; P < 0.001), revealing a significant increase in 24-h fat oxidation (42 +/- 6 vs. 81 +/- 7 g/day) and a decrease in carbohydrate oxidation (180 +/- 14 vs. 113 +/- 10 g/day; both P < 0.001). In conclusion, ST increases resting EE and fat oxidation, which may have important implications in improving the metabolic profile of older adults. The increase in resting EE may be partly explained by increased muscle mass.

5. Visser M, van der Horst A, de Groot LC, Deurenberg P & van Staveren WA (1995): Energy cost of physical activities in healthy elderly women. Metabolism, 44, 1046-1051.

Department of Human Nutrition, Wageningen Agricultural University, The Netherlands. In recent studies, daily physical activity ratios (PARs) greater than the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU) reference value of 1.5 have been reported for elderly men and women. The purpose of this study was to investigate whether a high PAR in elderly subjects can be explained by a higher energy cost of physical activities (EEact). To this end, 12 elderly women aged 69 to 82 years, completed physical activity diaries during a 2-day stay in a respiration chamber. From these diaries, total daily energy expenditure (TEE) in the calorimeter was estimated (TEEfac) using FAO/WHO/UNU PARs for physical activities and measured resting metabolic rate (RMR). TEEfac was 7.0 +/- 0.9 MJ/d (PAR, 1.35 +/- 0.06). TEE was also measured in the chamber (TEEcal) and was 8.3 +/- 1.3 MJ/d (PAR, 1.60 +/- 0.16). TEEfac was 14.8% +/- 8.1% lower than TEEcal. To investigate whether the underestimation of TEEcal was due to a higher EEact in the elderly women as compared with the FAO/WHO/UNU references, EEact of six specific activities ranging from sitting at rest to walking on a treadmill at self-chosen speed was measured with a ventilated-hood system. Individually measured PARs of the six activities were similar to FAO/WHO/UNU reference PARs. This study suggests that in elderly women a high TEEcal is not explained by EEact during nonstandardized physical activities performed at self-chosen speeds. Whether these results car. be extrapolated to the free-living environment needs to be investigated further.

6. Voorrips LE, van Acker TMJ, Deurenberg P & van Staveren WA (1993): Energy expenditure at rest and during standardized activities: a comparison between elderly and middle-aged women. Am. J. Clin. Nutr. 58,15-20.

Department of Human Nutrition, Wageningen Agricultural University, The Netherlands. To estimate energy expenditure (EE) in elderly subjects, more age-specific data are required on energy costs of standardized activities. EE was assessed by using indirect calorimetry in 28 women aged 72 +/- 4 y (mean +/- SD) and in 29 middle-aged women (42 +/- 1 y) at rest (resting metabolic rate; RMR) and during sitting, sitting with standardized arm activity, and walking on a treadmill at 3 km/in. RMR and EE during sitting, and sitting with standardized arm activity did not differ significantly between the groups, although EE expressed as a ratio of arm activity to RMR (physical activity ratio, PAR) tended to be higher in the elderly subjects. Walking EE was significantly higher in the elderly women (16.4 +/-4.0 kJ/min) than in the middle-aged women (12.7 +/- 2.3 kJ/min), also when expressed as PAR. It is suggested that elderly women walk less efficiently. Because PARs are frequently used to estimate daily EE, it is important to note that additional age-specific data might be required.

7. Waters RL, Hislop HJ, Perry J. Thomas L & Campbell J (1983): Comparative cost of walking in young and old adults. J.Orthop.Res. 1, 73-76.

Normative data that summarize the energy requirements and gait characteristics of level outdoor walking were determined in 111 normal subjects between the ages of 20 and 80 years. Subjects were divided into two age groups: young adults (20-59 years) and senior subjects (6080 years). The mean rate of oxygen consumption for young adults and senior subjects did not significantly differ, averaging 11.9 ml/kg-min for both groups. The data on heart rate paralleled the findings on oxygen consumption, averaging 100 and 103 beats/min, respectively. The net oxygen cost per meter walked for senior subjects, 0.16 ml/kg-m, was significantly greater (p < 0.0005) than the value for young adults, 0.15 ml/kg-m, due to a decline in the average walking speed. The average gait velocity for senior subjects, 73 m/min, was statistically significantly less (p < 0.0005) than the values for the younger adults, 80 m/mint

8. Waters RL, Lunsford BR, Perry J & Byrd R (1988): Energy-speed relationship of walking: standard tables. J.Orthop.Res. 6, 215-222.

Department of Surgery, Rancho Los Amigos Medical Center, Downey 90242. The energy expenditure of level walking was measured in 260 normal male and female subjects walking around a 60.5m-circular outdoor track. Subjects were divided into four age groups (children, 612 years; teens; young adults, 20-59 years; and senior adults, 60-80 years). Oxygen consumption was measured with a modified Douglas Bag technique during the fourth and fifth minutes of each trial. Standard tables according to age and sex were derived for the average energy expenditure (rate of oxygen uptake, energy cost per meter, and heart rate) and for the gait characteristics (speed, cadence, stride length) at the subjects' customary slow, normal, and fast walking speeds. Statistical analysis was performed to determine the energy-speed relationship for the different age groups to derive normative tables for the rate of oxygen uptake throughout the range of customary walking velocities.

6. Review papers

1. Anonymous (1967): Energy cost of simulated space activities. Nutr.Rev. 25, 301-304.

Simulation of space conditions indicates that human energy requirements are decreased by reduced G-force but increased by suit pressurization. Heat removal may be inadequate for extravehicular activities in present suits. This paper presents the findings from studies which have attempted to simulate various features of space activities, such as reduced gravitational forces and features related to life support systems.

2. Anonymous (1971): Ergonomics guide to assessment of metabolic and cardiac costs of physical work. Am.lnd.Hyg.Assoc.J. 32, 560-564.

This paper discusses the significance of and ways to determine the energy costs and heart rates associated with the performance of physical tasks. Such information may be of use in achieving adjustments between the physical capacities of workers and job demands. Some data from the literature on the energy cost of various occupational activities are presented [not original abstract]

3. Ainsworth BE, Haskell WL, Leon AS, Jacobs DR, Jr., Montoye HJ, Sallis JF & Paffenbarger RS, Jr. (1993): Compendium of physical activities: classification of energy costs of physical activitites. Med.Sci.Sport Exerc. 25, 71-80.

A coding scheme is presented for classifying physical activity by rate of energy expenditure, ie, by intensity. Energy cost was established by a review of published and unpublished data. This coding scheme employs 5 digits that classify activity by purpose (de, sports, occupation, self-care), the specific type of activity, and its intensity as the ratio of work metabolic rate to resting metabolic rate (METs). Energy expenditure in kilocalories or kilocalories per kilogram body weight can be estimated for all activitites, specific activitites, or activity types. General use of this coding scheme would enhance the comparability of results across studies using self report of physical activity.

4. Jette M, Sidney K & Blumchen G (1990): Metabolic equivalents (METS) in exercise testing, exercise prescription, and evaluation of functional capacity. Clin.Cardiol. 13, 555-565.

Department of Kinanthropology, School of Human Kinetics, University of Ottawa, Canada. One metabolic equivalent (MET) is defined as the amount of oxygen consumed while sitting at rest and is equal to 3.5 ml 02 per kg body weight x min. The MET concept represents a simple, practical, and easily understood procedure for expressing the energy cost of physical activities as a multiple of the resting metabolic rate. The energy cost of an activity can be determined by dividing the relative oxygen cost of the activity (ml O2/kg/min) x by 3.5. This article summarizes and presents energy expenditure values for numerous household and recreational activities in both METS and watts units. Also, the intensity levels (in METS) for selected exercise protocols are compared stage by stage. In spite of its limitations, the MET concept provides a convenient method to describe the functional capacity or exercise tolerance of an individual as determined from progressive exercise testing and to define a repertoire of physical activities in which a person may participate safely, without exceeding a prescribed intensity level.

5. Lane HW (1 992): Energy requirements for space flight. J.Nutr. 122, 13-18.

Biomedical Operations and Research Branch, NASA-Johnson Space Center, Houston, TX 77058. Both the United States and the Soviet Union perform human space research. This paper reviews data available on energy metabolism in the microgravity of space flight. The level of energy utilization in space seems to be similar to that on Earth, as does energy availability. However, despite adequate intake of energy and protein and in-flight exercise, lean body mass was catabolized, as indicated by negative nitrogen balance. Metabolic studies during simulated microgravity (bed rest) and true microgravity in flight have shown changes in blood glucose, fatty acids and insulin concentrations, suggesting that energy metabolism may be altered during space flight. Future research should focus on the interactions of lean body mass, diet and exercise in space, and their roles in energy metabolism during space flight.

6. McCarroll JE, Goldman RF & Denniston JC (1979): Food intake and energy expenditure in cold weather military training. Mil Med. 144, 606-610.

This paper examines the question of energy demands of military activities in a cold environment and the associated food requirements. The metabolic effects of cold on skin temperature are shivering and non-shivering thermogenesis. These effects are negligible for the well-clothed person since the temperature is not lowered. Acclimatization to cold is a complicated phenomenon which has only slight gains in comfort compared with the time required to achieve it. Energy expenditure (activity) is the primary determinant of food requirements. An energy expenditure prediction is presented for practical use when the following factors are known: load carried, velocity of movement, and the type of terrain. Estimates of energy expenditure for various military activities are presented, in order to allow the reader to make rough estimates of energy demands upon troops in varying terrains and using different means of mobility. Using these estimates, a scenario can be created and food requirements can be predicted.

7. Numajiri K & Shindo H (1970): Energy expenditure of industrial workers in Japan. J.Sci.Labour, 46, 383-388.

This paper discusses the use of RMR (relative metabolic rate) as an indicator of the intensity of muscular work. RMR is defined as the quotient of energy requirement of work by basal metabolism:

R = resting metabolism
W = work metabolism
BM = basal metabolism

RMR can be converted into energy expenditure: energy expenditure (kcals) = (RMR x 1.2) x BM

1.2 is the average ratio of resting metabolism to basal metabolism.

Some previously gathered data on the RMR of various occupational activities are presented and also the daily energy expenditure of some occupational groups.

8. Shephard RJ (1982): The daily work-load of the postal carrier. J.Hum.Ergol. 11, 157-164.

An analysis of physical demand shows that a male postal carrier may sustain an 8 hr energy expenditure of 21.8 kJ.min^-1, with an average of 28.4 kJ.min^-1 for 4-5 hr of walking the route, and a peak output of 40.6 kJ.min^-1. Comparable figures for a female carrier are 17.7, 23.0 and 32.7 kJ.min^-1. The work is close to the physiological limit for older individuals, but complaints are few due to (i) the conditioning effect of employment, (ii) selective elimination of inappropriate employees, (iii) relatively early retirement, and (iv) ability of older employees to bid for easier mail routes.

9. Shephard RJ (1987): Science and medicine of canoeing and kayaking. Sports Med. 4, 19-33. Canoeing and kayaking are upper-body sports that make varying demands on the body, depending on the type of contest and the distance covered. The shorter events (500 m) are primarily anaerobic (2 minutes of exercise), calling for powerful shoulder muscles with a high proportion of fast-twitch fibres. In contrast, 10,000 m events call for aerobic work to be performed by the arms. Such contestants need a high proportion of slow-twitch fibres, and an ability to develop close to 100% of their leg maximum oxygen intake when paddling. In slalom and whitewater contests, the value of physiological testing is somewhat limited, since performance is strongly influenced by experience and the ability to make precisely judged rapid paddling efforts under considerable emotional stress. Paddlers face dangers from their hostile cold water environment; causes of fatalities (drowning, cardiac arrest, ventricular fibrillation and hypothermia) are briefly reviewed. Medical problems include provision of adequate nutrition and a clean water supply, effects of repeated immersion (softening of the skin, blistering, paronychial infections, sinusitis, otitis), varicose veins (secondary to thoracic fixation) and hazards of exposure to fibreglass and polystyrene in the home workshop. Surgical problems include muscle sprains and mechanical injuries (haemotomas, lacerations, contusions, concussion, and fractures).

10. Torun B (1990): Energy cost of various physical activities in healthy children. In: Activity, energy expenditure and energy requirements of infants and children. Proceedings of an IDECG workshop held in Cambridge, Massachuseffs, USA, November 14-17, 1989, edited by B. Schurch, et al, pp. 139-183. IDECG, Switzerland.

Twenty-eight studies that measured the energy cost of several common activities of children were found through an extensive literature search and personal communications. The characteristics of the children, the method used to measure energy expenditure and the energy costs of the activities from each study are presented in summer tables. The children's basal metabolic rate (BMR) and the energy cost of activities per kg or as multiples of BMR (X BMR) were calculated to present the data uniformly. The activities were classified in ten categories. In most age groups there is no information about the energy cost of household work, agricultural chores, other common tasks, and many sports or games, especially for girls. Although the methodology varied between studies and the activities were not standardized, the data suggest that when energy costs are expressed as X BMR: (a) they are similar for boys and girls, (b) there are no age-related differences in sedentary activities, (c) the cost of walking and moving around increases from preschool years to mid-adolescence, and (d) energy costs from 15 years onwards are similar to those of adults. The use of energy costs of adults per kg of body weight to calculate energy costs of children leads to errors which increase with decreasing age. Suggestions are made to estimate the energy costs of children based on their known or calculated BMR and from similar activities of adults expressed as fractional multiples of BMR. Additional investigations are necessary to confirm whether there are differences related to racial, geographic and socioeconomic conditions.