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close this bookBibliography of Studies of the Energy Cost of Physical Activity in Humans (London School of Hygiene & Tropical Medicine, 1997, 162 pages)
close this folder4. Adults
close this folder4.3 Sports and recreation
View the document4.3.1 Men
View the document4.3.2 Women
View the document4.3.3 Men & women

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 V2,05; 02 for the arms = V3,95/20.42; and 02 for the whole stroke = V2,70/4,38 (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 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, 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 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, 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, SEM 0.006 (ie about 0.22 ml 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 (0.0029, 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 (PB=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 (Etot/V, ml/kg.min) increases with the speed (v, m/s): Etot/v=0.049 + 0.44 X 10 -3 V2. At 10 m/s, Vtot/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 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 VO2 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 VO2 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 VO2, heart rate and VE VO2 tended to be higher during swimming with arm strokes only as compared with the whole stroke. Highest values for VO2, 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 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 showed better correlations and lower dispersions than 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 (Tes), 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 Ts 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, 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], 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/, 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/ (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/ 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 and 59.4 +/- 3.7 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 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 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.