Physiology and Occupational Physiology 9 Springer-Verlag 1983

Transcription

1 Eur J Appl Physiol (1983) 51: European Journal of Applied Physiology and Occupational Physiology 9 Springer-Verlag 1983 Load Optimization for the Wingate Anaerobic Test* R. Dotan and O. Bar-Or Department of Research and Sports Medicine, The Wingate Institute for Physical Education and Sports, Wingate 42902, Israel Summary. The purpose of the present study was to define the optimal loads (OL) for eliciting maximal power-outputs (PO) in the leg and arm modes of the 30 s Wingate Anaerobic Test (WANT). Eighteen female and seventeen male physical education students, respectively 20.6 _+ 1,6 and 24.1 _+ 2.5 years old, volunteered to participate. In each of the total five sessions, the test was administered twice on a convertible, mechanically braked cycle-ergometer, once for the legs and once for the arms. The five randomized, evenly-spaced resistance loads ranged from 2.43 to 5.39 Joule per pedal revolution per kg body weight (B. W.) for the legs, and from 1.96 to 3.92 for the arms. The measured variables were mean (MP 9 kg -1) and peak PO as well as absolute and relative measures of fatigue. A parabola-fitting technique was employed to define the optimal loads from the MP 9 kg -1 data. The resulting OL were 5.04 and 5.13 Joule 9 Rev -1 9 kg B.W.-1 in the leg and 2.82 and 3.52 in the arm tests for the women and men, respectively. OL were shown to depend on PO magnitude, However, within a two-load span (0.98 Joule 9 Rev -1 9 kg B.W. -1) about the OL, MP 9 kg -1 did not vary by more than 1.4% in the leg and 2.2% in the arm tests. It is suggested that although the WAnT is rather insensitive to moderate variation in load assignment, improved results could be obtained by using the stated OL as guidelines that may be modified according to individual body build, composition, and, particularly, anaerobic fitness level. Key words: Anaerobic power - Leg ergometry - Cycle-ergometer - Load optimization Introduction Designed to fill the void in the traditional array of physical performance tests, the Wingate Anaerobic Test (WANT) has become increasingly popular (Mayers Offprints requests to: R. Dotan (address see above) * This study was funded by a research grant from the Sports and Physical Education Authority, The Ministry of Education and Culture, Israel

2 410 R. Dotan and O. Bar-Or and Gutin 1979; Jacobs 1980; Quintana et al. 1981) ever since it's introduction in 1974 (Ayalon et al. 1974). Although central in proper test administration, load selection has been based on only a limited pilot study (Ayalon et al. 1974) and subsequent data on children (Bar-Or 1980). As part of the WAnT's development and validation project (e.g.: Bar-Or et al. 1977) the present study is concerned with power maximization in the WAnT via the optimization of load selection for its four main categories (men, women, legs, and arms). A secondary purpose was to observe the changes in other WAnT indices which take place with the modification of cranking force. Methods Eighteen female and seventeen male physical education students, having signed an informed consent form, volunteered to take part in this study. Their average ages, weights and heights were: 20.6 _+ 1.6 yr, 56.9 _+ 4.1kg and _+ 5.4 cm for the women and yr, 66.9 _+ 6.6 kg and cm for the men. Typically, the subjects reported to the laboratory 5 times. Sessions were spaced by at least 24 h and on the average by intervals of more than one week. In each session, the 30 s WAnt was performed twice, once by the arms and once by the legs at random, with at least a 30 rain rest between. Five different friction loads were used for the leg and five for the arm tests in a randomized order (see Table 1 for the actual load values). Loads were relative to body weight (B.W.) taken at the first session. They were centered around those loads routinely used in our laboratory in recent years (4.41 Joule - Rev -1 9 kg B.W. -1 for the legs and 2.94 for the arms). The test was administered on a Fleisch (Metabo, Switzerland) friction-type cycle-ergometer with 170 mm long cranks. The ergometer was readily convertible between its leg and arm testing modes. A warm-up typically preceded each test by 3-5 min. It consisted of approximately 3 rain of low intensity cranking at the mode about to be tested and was interspersed by 2-3 all-out sprints of 4-7 s duration against the highest resistance that would still allow a sprinting pace. Following the rest period the subject was seated on the ergometer and, in the case of leg testing, had his/her feet fastened to the pedals by means of racing-type toe-clips and seat height was determined and recorded for reproduction in the subsequent tests. To the command,,start" the subject commenced cranking as fast as he/she could against the ergometer's inertial resistance only. The full, predetermined resistance load was applied within 3-4 s once the inertial resistance had been overcome. Pedal revolution count started at that instant and lasted precisely 30 s. Subjects were instructed to avoid pacing and maintain an all-out effort throughout the test. Pedal revolutions were counted either electro-mechanically or photo-electrically with resolutions of 0.5 or 0.2 revolution, respectively. In addition to the 30 s total, revolutions were cummulatively recorded for each 5 s test segment, as well. From these data the highest (normally the first or second) and the lowest powered (always the last) 5 s values were extracted for calculating the parameters described below. The maximization of the body-weight-relative mean power (MP 9 kg 1) was the main objective of this study. It was calculated from the product of the respective B.W.-relative load and total number of revolutions multiplied by the distance covered by the flywheel in relation to the friction belt per crank revolution (10 m in the Fleisch ergometer). In addition, we tested the following indices' behavior with the change in load: B.W.-relative peak-power (PP. kg -1) - defined as the highest 5 s power output; fatigue percent coefficient (F%) - highest minus lowest 5 s power-outputs divided by the highest output and multiplied by 100; and fatigue slope (FS) - highest minus lowest 5 s output divided by the time in seconds within which the change took place. Means + 1 SE were calculated for each of the four parameters in the five respective loads of both legs and arms for the men and women alike. A parabolic regression calculation was applied to each set of MP - kg -1 means and the maxima were defined as the respective optima. The same technique was applied to the individual MP. kg -1 data sets in order to construct frequency distributions of the individual maxima and to relate them to the respective maxima derived from the group means.

3 Load Optimization for the Wingate Anaerobic Test 411 Table 1. Resistance loads used for the leg and arm tests Load number I II III IV V Legs Fleisch weights, g 9 kg B.W Joule 9 Rev -1 9 kg B.W. -1 ~ Arms Fleisch weights, g 9 kg B.W Joule 9 Rev -a 9 kg B.W. -1 a a Values in these units are universal and, therefore, identical to all constant-load cycle-ergometers regardless of their mechanical configuration Results The results obtained in the present study are graphically depicted in Figs. 1 and 2. The best-fit parabolae are applied to the MP. kg -t data and their indicated maxima define the respective load optima. These optimal load values are given in Table 2 which, in addition, provides the corresponding cranking-rate and power-output values as well as previous leg-test data on year old girls and boys (Bar-Or, 1980). A trend can be observed of increasing optimal loads and cranking rates from girls to boys, to women to men. Table 3 shows the frequency distribution of the individual load optima similarly derived by the use of the parabola-fitting technique. It should be noted that, without exception, the highest frequencies fall in those same load-ranges in which occur the group-optima. Power-output sensitivity to load application errors has been defined as the largest percent-deviation of MP. kg -1 from its established maximum consequent to changing the applied resistance within a two-load range about the optimum. That deviation was 1.35, 1.41 and 2.16, 1.66% for the women and men's leg and womens and mens's arm tests, respectively. Inter-sex comparison reveals that the women's MP. kg -1 maximum was 19.7% lower than the men's in the leg test and 32.7% in the arm's. The corresponding disparity in the optimal loads amounted to only 1.8 % and 22.1%, respectively. Arm/leg MP 9 kg -1 ratio was 47.6% in the female and 56.8% in the male subjects, while the corresponding optimal load ratios were 56.0% and 70.6%, respectively. As expected, PP 9 kg -1 appears to conform to a parabolic function as does MP 9 kg -~ except that its maxima occur at considerably higher loads than those optimal for maximizing MP-kg -1. It is evident that a single test cannot be optimized for both kinds of power. Both fatigue parameters exhibit what appears to be a linear behavior in all four categories with a trend of crossing-over of the male and female F% lines in both modes of the test. The arm modes shows a considerably wider range of F% values than does the leg mode and in the women it is more evident than in the men.

4 LEGS MP'Kg" i/~1~\ 12 I I I I I I i I I l L~J 48 4C 32 F% 1~ m m l l l 3,5 4,5 5,5 T i~ FS I I I I I 3,5 4,5 5.5 Fig. 1. Mean values of mean and peak power outputs (+ 1 SE) normalized for body weight as well as fatigue-percent coefficient and fatigue slope (MP. kg -1, PP. kg -1, F%, and FS, respectively) at increasing ergometer leg-test loads in men (O) and women (9 Best-fit parabolic curves have been applied to the MP. kg -1 data. The curves' maxima define the respective load optima -I -I L 0 A D S, JOULE.REV.Kg T~ -[ MP'KQ ARMS ~f;ll L 7 / =5 /-I pp,kg /g %\ 3 I I I I I I I I I I 6O FX 15 FS 40? 20 I I I I I ! I 2 ' Fig. 2. Same as Fig. 1, but for the arms -I -1 L 0 A I) S, 30ULE-REV.Kg

5 Load Optimization for the Wingate Anaerobic Test 413 Table 2. Summary of the derived optimal load and cranking-rate values for the respective leg and arm mean-power, including previous data on year old girls and boys Legs Arms years old Women Men Women Men Girls Boys Optimal loads Joule 9 Rev -1 9 kg B.W.-1 a Fleisch ergometer, g 9 kg B.W.-1 Monark equivalent, Kp 9 kg B.W.-1 Cranking rates, Rev - min- 1 Maximal mean power, Watt - kg B.W. -1 b a Calculated by the division of optimal-load into the respective maximal mean power b Derived from the calculated best-fit parabolic curve Table 3. Frequency distribution of occurence of individual mean power maxima a in relation to load Load at which maximum occured u Below Above 1st 1st 2nd 3rd 4th 5th 5th Men Legs c 3 3 n = 17 Arms ~ - 2 Women Legs r 3 3 n = 18 Arms c 1-2 a Individual maxima were also parabolically determined b load c Range within which mean group-maximum occured Discussion The force-velocity interrelationship was first formulated by Hill (1938). It has traditionally been referred to as "classical" since it serves in understanding numerous performance situations, especially where performance maximization is the main objective. Power, the product of the two factors, can take, therefore, a virtually infinite number of values. Thus, optimal solutions may vary when the performance criterion is absolute maximal power (Harrison 1970; Sargeant 1978), power efficiency(saitoet al. 1974; Seabury et al. 1977; Suzuki 1979)or power endurance (apparently uninvestigated, so far, in this respect). Such

6 414 R. Dotan and O. Bar-Or solutions could change also in relation to different modes of performance, such as: swimming (Craig and Pendergast 1979), cycle-ergometry (Moffatt and Stanford 1978; Seabury et al. 1977), competitive cycling (Hagberg et al. 1981; Kyle and Mastropaolo 1976; Ulmer 1969), free running (Cavagna et al. 1971; Luhtanen and Komi 1978; Saito et al. 1974) or treadmill ergometry (Taylor et al. 1955). Within the range of the force-velocity interrelationships, those associated with maximized short-term power should be expected to most closely approximate the maximum single contraction as defined by the "classical" force-velocity curve (Hill 1938). That is due to the independence of such power from factors that modify longer-duration performances such as: efficiency of oxygen utilization (Pugh 1974; Seabury et al. 1977), muscular blood-flow (TCnnesen 1964) or perceived exertion (L611gen et al. 1975, 1977). Deviations from the classical relationship are mostly due to the onset of fatigue and the necessary muscular coordination associated with repetitive, high frequency motion compared with an isolated contraction. Maximizing the short-duration power in cycling is further complicated by the circular motion of the pedals which affects the nature of force application and increases the degree of the skill and coordination required for the given motion-sequence frequency (e.g.: Soden and Adeyefa 1979). Also, it has been shown (Kaneko and Yamazaki 1978) that the internal work associated with the acceleration and deceleration of the leg mass grows with the square of the increasing pedalling rate. Thus, the energy loss, that at 80 RPM already amounts to some 5% of the external power-output, would approach and even exceed 20% at 160 RPM. It follows, therefore, that with changing maximal power-outputs, variations in cycling rates should be more limited than the corresponding changes in the applied force. This assymetry is substantiated by the present study's findings. For instance, the greater power of the legs, compared with the arms, in both sexes (Table 2), was achieved by increasing the applied forces (optimal loads) (41.7% and 78.7 %, respectively) more than by elevation of the corresponding pedalling rates (24.2% and 18.9%). At present we can provide no explanation as to why this phenomenon is not fully evidenced between the sexes as well. Another concept that emerges from the above as well as from theoretical mechanistic grounds is that an optimal load depends on the absolute power-output with which it is associated. This concept is further augmented by the observation (Figs. 1 and 2) that PP 9 kg -1 load-optima are much higher than those corresponding to MP 9 kg -1. Indeed, in 3 out of 4 instances these optima lie clearly above the investigated load range. The practical conclusion to be drawn out of this is that optimal load-assignment should take into account not only sex, age or test-mode, but anaerobic fitness level as well. Aside from the optimal load for the women's arm-test all other load-optima proved higher than those previously used in our laboratory. An Edmonton, Alberta, study (Evans and Quinney 1981) using a different protocol, investigated leg optimal load for the WAnT in men and found a still higher optimal value. There are, however, several arguments for favoring the present study's findings. One is the larger number of subjects and the smaller

7 Load Optimization for the Wingate Anaerobic Test 415 standard deviation of the MP 9 kg -1 in this study (17 vs. 12 man and vs W-kg -1, respectively). More importantly, the Edmonton study's power-vs-load curve does not resemble any biologically-compatible form (any inverted U-like function) and actually has four maxima rather than the expected single peak. Within a two-load span (0.98 Joule 9 Rev -1 9 kg -I) surrounding the claimed optimum, power-output in that study ranges over some 11% compared to the maximum, while the corresponding value in the present study is only 1.4%. Even in the case of the women's arm-test, in the present study, where that load range constitutes a greater proportion of the absolute load, that figure does not exceed 2.2%. Finally, it should be noted that while Evans and Quinney's recommended optimum is 10.6% higher, their maximal MP-kg -1 mean is, nevertheless, 2.8% lower relative to our results. That is so, inspite of the reported inclusion of several athletes in the Edmonton study. This observation raises the question of whether true maxima, and therefore, true optima were indeed reached in the cited study. Alternately, a question can be asked concerning the comparability of the ergometers used in the two studies (Monark vs. Fleisch). A special case in point is differential inertial characteristics and their effect on optimized loads and maximized power-outputs. This question has not yet been investigated in relation to a maximal, short-term cycling task. Fatigue, in either criterion form used in the present study (Figs. 1 and 2) can not be expected but to rise with increasing loads. Changes associated with the attainment of optimal loads could only take the form of an inflection point or some other change in slope. This could not be substantiated in our findings. However, as could be anticipated, F% spans a greater range (steeper slope) in the women in whom the employed load-range constitutes a greater proportion of their absolute muscular strength in both the legs and arms. It may be of interest that at all test categories, excluding women's arm test, F% values at the respective optimal loads are practically identical (between 44.4 and 46.6 %). This observation may be suggestive of the possibility that a specific fatigue rate (percent) is associated with optimized resistance or maximized performance. Only 33-56% of the individual MP 9 kg -1 maxima fall within the load range in which the group optima occur (Table 3). This coupled with the observation that the load optima are power-dependent, appears to imply that a large individual variation exists in the location of load-optima. It is suggested, therefore, that the stated optimal-load values be taken as group or population load-selection guidelines that could be modified to a moderate extent to accommodate interindividual differences. Conclusions The main findings of the present study, relevant to populations similar to our subjects, were the following: 1. Men's optimal loads in the Wingate Anaerobic Test are 5.13 Joule 9 Rev -1 9 kg B.W. -1 for the legs and 3.52 for the arms. The corresponding values for the women are 5.04 and 2.82 Joule 9 Rev -1 9 kg B.W. -1

8 416 R. Dotan and O. Bar-Or 2. The WAnT is rather insensitive to moderate variation in load assignment. Deviations from optimum, of Joule 9 Rev -1 9 kg B.W., reduce power-output by less than 1.4% in the leg and 2.2% in the arm-test performance. This adds to the test's already demonstrated reliability (Bar-Or et al. 1977; Dotan and Bar-Or 1980; Jacobs 1980). 3. Perfect load optimization depends on maximal power. Consequently, loads may be modified by taking into account anaerobic fitness in the relevant muscle group as well as deviations from normal body build or composition. However, as was stated above, moderate errors in accounting for individual variation would result in practically insignificant deviations from the true power maxima. Acknowledgements. The authors wish to thankfully acknowledge the technical help of Eva Dubroni, Cochava Golan, Sara Mark, Shula Pentelka and Miki Sheinowitz, without whom the optimal work-load could have proven much heavier. References Ayalon A, Inbar O, Bar-Or O (1974) Relationship among measurements of explosive strength and aerobic power. In: Nelson RC, Morehouse CA (eds) Biomechanics IV. International Series on Sport Sciences, vol I. MacMillan, New York, pp Bar-Or O, Dotan R, Inbar O (1977) A 30 s all-out ergometry test - its reliability and validity for anaerobic capacity [Abstr]. Isr J Med Sci 13: Bar-Or O (1980) Um novo teste de capacidade anaerobica - characteristica e applicabilidade. Med Esporte-Porto Alegre 5 : Cavagna GA, Komarek L, Mazzoleni S (1971) The mechanics of sprint running. J Physiol (Lond) 217: Craig Jr, AB, Pendergast R (1979) Relationships of stroke rate, distance per stroke and velocity in competitive swimming. Med Sci Sports 2: Dotan R, Bar-Or O (1980) Climatic heat stress and performance in the Wingate Anaerobic Test. Eur J Appl Physiol 44: Evans JA, Quinney HA (1981) Determination of resistance settings for an aerobic power testing. Can J Appl Sport Sci 6:53-56 Hagberg JM, Mullin JP, Giese MD, Spitznagel E (1981) Effect of pedalling rate on submaximal exercise responses of competitive cyclists. J Appl Physiol 51 : Harrison JY (1970) Maximizing human power output by suitable selection of motion cycle and load. Human Factors 12: Hill AV (1938) The heat of shortening and the dynamic constants of muscle. Proc R Soc B 126 : Jacobs I (1980) The effects of thermal dehydration on performance of the Wingate Anaerobic Test. Int J Sports Med 1:21-24 Kaneko M, Yamazaki T (1978) Internal mechanical work due to velocity changes of the limb in working on a bicycle ergometer. In: Asmussen E, JCrgensen K (eds) Biomechanics VI-A. International series on biomechanics, vol IIA. University Park Press, Baltimore, pp Kyle CR, Mastropaolo J (1976) Predicting racing bicyclist performance using the unbraked flywheel method of bicycle ergometry. Presented at the International Congress of Physical Activity Sciences, Quebec City, Canada L611gen H, Ulmer HV, Gross R, Wilbert G, Nieding GV (1975) Methodical aspects of perceived exertion rating and its relation to pedalling rate and rotating mass. Eur J Appl Physiol 34 : L611gen H, Ulmer HV, Nieding GV (1977) Heart rate and perceptual response to exercise with different pedalling speed in normal subjects and patients. Eur J Appl Physiol 37:

9 Load Optimization for the Wingate Anaerobic Test 417 Luhtanen P, Komi PV (1978) Mechanical factors influencing running speed. In: Assmussen E, JCrgensen K (eds) Biomechanics VI-A. International series on biomechanics, vol IIA, University Park Press, Baltimore, pp Mayers N, Gutin B (1979) Physiological characteristics of elite prepubertal cross-country runners. Med Sci Sports 11: Moffatt RJ, Stanford BA (1978) Effects of pedalling rate changes on maximal oxygen uptake and perceived effort during bicycle ergometer work. Med Sci Sports 10:27-31 Pugh LGCE (1974) The relation of oxygen intake and speed in competition cycling and comparative observations on the bicycle ergometer. J Physiol 241: Quintana G, Guig A, Huberman J, Holtztsy M, Donoso M (1981) Application and analysis of the measurement of anaerobic capacity (Wingate Test) in different sports [in Spanish]. Presented at the Pan-American Congress and International Course on Sports Medicine and Exercise Science, Miami Saito M, Kobayashi K, Mayashita M, Hoshikawa T (1974) Temporal patterns in running. In: Nelson RC, Morehouse CA (eds) Biomechanics IV. International Series on Sports Sciences, vol 1, MacMillan, New York, pp Sargeant AJ (1978) Force velocity relationship and power output in short-term dynamic exercise. Fed Proc 37:429 (Abstr) Seabury JJ, Adams WC, Ramey MR (1977) The influence of pedalling rate and power output on energy expenditure during bicycle ergometry. Ergonomics 20: Soden PD, Adeyefa BA (1979) Force applied to a bicycle during normal cycling. J Biomech 12: Suzuki Y (1979) Mechanical efficiency of fast and slow twitch muscle fibers in man during cycling. J Appl Physiol 47 : Taylor HL, Buskirk E, Henschel A (1955) Maximal oxygen intake as an objective measure of cardiorespiratory performance. J Appl Physiol 8:73-80 TCnnesen KH (1964) Blood flow through muscle during rythmic contraction measured by 133-xenon. Scand J Clin Lab Invest 16: Ulmer HV (1969) Die Abhfingigkeit des Leistungsempfindens yon der Tretfrequenz bei Radsportlern. Sportarzt Sportmed 20: Accepted February 22, 1983