|Bibliography of Studies of the Energy Cost of Physical Activity in Humans (London School of Hygiene & Tropical Medicine, 1997, 162 pages)|
|4.2 Occupational activities|
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]
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.