THE EFFECTS OF TRAINING ON ANAEROBIC CAPACITY, ANAEROBIC POWER, AND RATE OF FATIGUE OF PREPUBERTAL, ELITE ICE HOCKEY PLAYERS by JAMES EDWARD POTTS B.P.E., The University of B r i t i s h Columbia, 1983 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION i n THE FACULTY OF GRADUATE STUDIES School of Physical Education We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA September 1985 © J a m e s Edward P o t t s , 1985 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head o f my department or by h i s o r her r e p r e s e n t a t i v e s . I t i s understood t h a t copying or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be allowed without my w r i t t e n p e r m i s s i o n . James Edward Potts Department o f Physical Education The U n i v e r s i t y of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date September 30, 1985 DE-6 (3/81) 11 ABSTRACT The purpose of t h i s study was to evaluate the effects of a 16 week tr a i n i n g programme on selected on-ice and laboratory variables of 9-10 year-old boys involved i n a competitive ice hockey programme. Twenty-four players from two A-level representative teams were selected as subjects for t h i s study. Players from one team served as the t r a i n i n g group while players from the second team served as the age-matched control group. On-ice measures were calculated from a Repeat Sprint Skate (RSS) whereby subjects performed 4 repetitions of 91.45 metres, commencing each r e p e t i t i o n every 35 seconds. Laboratory measures included a Wingate Anaerobic Test (WAnT) which was extended to 40 seconds, an Anaerobic Speed Test (AST), and strength and power measurements (30, 100, 180 deg*sec "^) of the quadricep and hamstring muscle groups. Results from t h i s study indicate that the t r a i n i n g group showed s i g n i f i c a n t (p = .05) improvement over the control group i n the following variables: (1) the AST; (2) RQ (30 deg*sec _ 1); (3) RH (30 deg*sec _ 1); (4) RH (100 deg*sec - 1) ; (5) LH (30 deg* -1. sec ). Findings from t h i s study indicate that intense anaerobic t r a i n i n g w i l l benefit prepubertal ice hockey players on selected anaerobic and strength measures. i i i TABLE OF CONTENTS ABSTRACT i i LIST OF TABLES i v LIST OF FIGURES v ACKNOWLEDGEMENT v i CHAPTER I INTRODUCTION 1 II METHODS AND PROCEDURES 6 SUBJECTS 6 TESTING PROCEDURES 6 TESTING PROTOCOLS 7 TRAINING INTERVENTION 10 STATISTICAL ANALYSIS 11 III RESULTS 13 IV DISCUSSION 22 V SUMMARY AND CONCLUSIONS 33 SUMMARY 33 CONCLUSIONS 35 RECOMMENDATIONS FOR FURTHER RESEARCH 36 REFERENCES 37 APPENDIX A - REVIEW OF LITERATURE 41 - REFERENCES 61 APPENDIX B - DEF. AND CALC. OF ANAEROBIC CAPACITY 72 APPENDIX C - DEF. AND CALC. OF ANAEROBIC POWER 73 APPENDIX D - DEF. AND CALC. OF RATE OF FATIGUE 74 APPENDIX E - PROTOCOL AND CONSENT FORM 75 i v LIST OF TABLES TABLE I Multivariate Analysis of Variance for 16 Physical Characteristics II Multivariate Analysis of Variance for 17 Laboratory Metabolic Variables I I I Multivariate Analysis of Variance for 18 On-Ice Metabolic Variables IV Time Analysis of the Repeat Sprint Skate 19 V Multivariate Analysis of Variance for 20 Anterior Thigh Muscles (Quadriceps) Strength and Power Measurements VI Multivariate Analysis of Variance for 21 Posterior Thigh Muscles (Hamstrings) Strength and Power Measurements LIST OF FIGURES FIGURE 1 Schematic Representation Repeat Sprint Skate ACKNOWLEDGEMENT I would l i k e to express my sincere appreciation and gratitude for those who assisted me i n the completion of thi s thesis: committee chairman, Dr. E. Rhodes, and committee members, Dr. R. Lloyd-Smith, Dr. R. Mosher, and Dr. J . Taunton. I would l i k e to also thank Dr. B. Ho and the s t a f f of the Department of Radiology at H.S.C.H. for the i r valuable guidance and patience. F i n a l l y , without the support of my family and friends t h i s task would have been much more arduous and d i f f i c u l t to complete. INTRODUCTION There i s a paucity of information available on the physiological characteristics of e l i t e prepubertal athletes. Considering the obvious importance of early success and involvement i n a t h l e t i c s for the eventual development and mastery of sport s k i l l s , the successful athlete who has not demonstrated an early a b i l i t y i n his sport i s obviously rare. This i s c e r t a i n l y true i n the sport of ice hockey. Previous research by Green and Houston (1975), Green et a l . (1978; 1972), and Seliger et a l . (1972) has attempted to define the acute stress placed on the various physiological systems i n response to playing ice hockey, and to correlate these changes with the diff e r e n t energy c a p a b i l i t i e s of the players. I t has been found that due to the intermittent nature of the game, wide variations e x i s t i n skating speed, durations i n play, and recovery periods (Green and Houston, 1975). Time-motion analyses have suggested that both aerobic and anaerobic metabolism may be s i g n i f i c a n t l y involved i n energy delivery depending on the characteristics of the p a r t i c u l a r s h i f t (Green and Houston, 1975). The actual amount of playing time during a game varies between 20-24 minutes, depending on the player's p o s i t i o n , his age, and the l e v e l of competition being played (Green et a l . , 1978; Seliger et a l . , 1972). This i s divided into approximately 15 to 18 s h i f t s on the i c e , each averaging 75-80 seconds, and separated by 3.5-4 minute recovery periods (Green et a l . , 1978; Seliger et a l . , 1972). In an indiv i d u a l s h i f t there may be 2 or 3 play stoppages, providing only 35 to 40 seconds of continuous a c t i v i t y interrupted by 25 to 30 second stoppages (Green et a l . , 1978; Seliger et a l . , 1972). The average distance covered during a s h i f t varies between 269-312 metres (Seliger et a l . , 1972). Research by Seliger et a l . (1972) demonstrated the r e l a t i v e contributions of both aerobic and anaerobic metabolism to the energetics of ice hockey. These results show that approximately 69% of the energy cost during an ice hockey match w i l l be covered by anaerobic metabolism. Previous studies by Cunningham and Faulkner (1969), Eriksson (1971), Eriksson et a l . (1974), Faria (1970), Fox et a l . (1973), Pollock et a l . (1969), Roskamm (1967), Sharkey and Holleman (1967), Sharkey (1970), and Thorstensson et a l . (1975) have shown that intensive t r a i n i n g can e l i c i t s i g n i f i c a n t improvements i n the function of metabolic processes involved i n energy release. Although these programmes appear j u s t i f i e d , very few attempts have been made to observe the effects of high int e n s i t y i n t e r v a l training on prepubertal children. The a b i l i t y of children to perform anaerobic-type a c t i v i t i e s 3. i s d i s t i n c t l y lower than that of adolescents and adults (Davies et a l . , 1972; diPrampero and Ce r r e t e l l y , 1969). Performance expressed i n absolute units of power (watts or joules) i s p o s i t i v e l y related to age (Eriksson, 1971). When standardized for body weight (watts*kg ^ or joules*kg "*"), however, the power produced by an 8 year-old boy i s s t i l l only 701 of that generated by an 11 year-old boy (Eriksson, 1971). Many studies which have investigated the t r a i n i n g effects on the anaerobic performance of children have u t i l i z e d the Wingate Anaerobic Test (WAnT). The r e l i a b i l i t y , v a l i d i t y , and the sens-i t i v i t y of the WAnT has been supported by investigations conducted mainly by researchers at the Wingate Institute i n I s r a e l (Ayalon et a l , 1975; Bar-Or, 1978; Grodjinovsky et a l , 1980; Inbar and Bar-Or, 1975). Mosher et a l . (1985) investigated the effects of a 12 week i n t e r v a l f itness t r a i n i n g programme on prepubertal, e l i t e - l e v e l male soccer players. Following the 12 weeks of t r a i n i n g the t r a i n i n g group was found to s i g n i f i c a n t l y increase t h e i r performance on a one mile run and on a modified Anaerobic Speed Test (AST), compared to age-matched controls. A s i g n i f i c a n t improvement was also evident on a drop-off index between t h e i r i n i t i a l and f i n a l (fastest-slowest) repeat runs, an indication of a lower rate of fatigue. 4. Tharp et a l . (1985) conducted a study with young male track athletes (x age = 13.3 ± 1.2 years) and found WAnT scores for anaerobic capacity and power were only moderately correlated with 50 and 600 yard run times. Grodjinovsky et a l . (1980) designed a study to determine whether or not the WAnT was sensitive to changes i n anaerobic performance of 11 to 13 year-old boys following a 6 week tr a i n i n g regimen. Anaerobic capacity and power showed an increase of approximately 3.5-5% following the t r a i n i n g period. The findings of such studies indicate that improvement i n the bioenergetic systems can occur i n the prepubertal male athlete. In the past, information on anaerobic capacity, anaerobic power, and rates of fatigue have been based on measurements from tests on maximal aerobic performance. The v a r i a t i o n i n protocols and the lack of stress on the anaerobic system underlie the wide range of reported values. The theoretical \ premise of these tests should be based on selecting a supra-maximal l e v e l of work designed to produce exhaustion. In such si t u a t i o n s , the major contribution to energy supply i s provided by anaerobic g l y c o l y s i s . Since l a c t i c acid i s the end product of such metabolism, changes i n blood lactate concentration should be found. Hence, the purpose of thi s study was to investigate the . effects of a 16 week tr a i n i n g programme on the anaerobic capacity, anaerobic power, and rates of fatigue of e l i t e prepubertal ice hockey players. I I METHODS AND PROCEDURES SUBJECTS Twenty-four male subjects, a l l of whom were between 112 and 129 months of age (x age = 126.60 i 4.27 months) at the beginning of t h i s study, were selected from volunteers of two representative hockey teams i n the greater Vancouver area. Players from one team served as the tr a i n i n g group (N = 11), while players from the second team served as the age-matched control group (N = 13). TESTING PROCEDURES The subjects were tested on two separate days with at least one day separating the laboratory testing from the on-ice testing. The series of tests were then repeated approximately 16 weeks l a t e r . The subjects were asked to r e f r a i n from any heavy training 24 hours p r i o r to and on the day of testing. Testing was administered at approximately the same time of day and under si m i l a r environmental conditions during both the preliminary and f i n a l testing sessions. Parental consent was obtained for each of the subjects i n th i s study (see appendix E) and no subject was allowed to parti c i p a t e i n the study without f i r s t being made aware of the purpose of the study, the testing procedures and protocols, and 7. any known problems or side-effects which might r e s u l t from the experimental procedures. During both the preliminary and f i n a l laboratory testing sessions height, weight, body composition (hydrostatic weighing), peak muscular strength, and anaerobic capacity, anaerobic power, rate of fatigue, and post-exercise blood lactate (extended Wingate Anaerobic Test) was determined on each subject. Two days l a t e r , on-ice measures of anaerobic capacity, anaerobic power, rate of fatigue, and post-exercise blood lactate were determined from a modified Repeat Sprint Skate (Reed et a l . , 1979). Skeletal x-rays of the l e f t hand and wrist were taken on each of the subjects at approximately the mid-point of the study. TESTING PROTOCOLS The physical characteristics which were determined included height, weight, and the percentage of body f a t . The percentage of body f a t was determined by a hydrostatic weighing technique outlined by Katch et a l . (1967). Laboratory measures of anaerobic capacity, anaerobic power, and rate of fatigue were calculated from the Wingate Anaerobic Test (WAnT) which was extended to 40 seconds. A Monarch ergometer was used, i n which one pedal revolution causes a 6 metre advance of the flywheel. The resistance setting was adjusted to 0.55 grams*kg 1 of body weight for t h i s study. On the command " s t a r t " the subject began to pedal as fast as he could. To overcome i n e r t i a , the i n i t i a l resistance was very low, but i t was quickly increased, and within 2-3 seconds reached the prescribed l e v e l . At that stage, the e l e c t r i c a l l y triggered counter was activated and measurements taken. The number of revolutions was recorded at 5 second intervals f o r the t o t a l of 40 seconds. Total mechanical work i n 40 seconds and the peak 5 second power output were taken as indices of anaerobic capacity and anaerobic power, respectively. The differences between the peak 5 second output and lowest 5 second output, divided by the time elapsed between the two points, was calculated. This value was used as an index of fatigue. Post-exercise blood lactate was determined from a c a p i l l a r y blood sample drawn from an unwarmed f i n g e r t i p . The sample was taken 5 minutes after the completion of exercise, stored, and then analyzed by a Komtron 640 automated lactate analyzer. An Anaerobic Speed Test (AST) was modified to a speed of 11.67 k.p.m. and 18% grade to produce AST scores i n the desired range (approximately 25-65 seconds). A l l subjects were given time to f a m i l i a r i z e themselves with the treadmill. Practice running was i n i t i a t e d at low speed and 0% grade and progressed i n three stages to the actual test speed and grade. On-ice measures of anaerobic capacity, anaerobic power, rates of fatigue, and speed % drop-off were calculated from a modified Repeat Sprint Skate (RSS). The RSS was administered as follows. Six pylons were placed on the ice surface as indicated i n figure 9 . 1. Timers were stationed at points A, B, and C, with position A serving as the starting point, position B serving as the end of the speed component of the test, and position C serving as the end of the repetition component of the test. On the command "start", the subject sprinted in a straight line from point A to point B where he came to a complete stop with both skates beyond the line between the two pylons. He immediately reversed directions and sprinted through point C, and then coasted back to the starting point A, where he prepared himself for the next t r i a l . The subjects began successive t r i a l s every 35 seconds of running time for 4 t r i a l s . Timers A, B, and C were instructed to start their stop-watches at the beginning of overt movement by the subject. Timer A was responsible for monitoring the running time and for ensuring that the subject began each t r i a l at the prescribed time. Timer B recorded the time for the subject to skate from point A to point B. Timer C recorded the total time for the subject to move from point A to point B and back through to point C. Post-exercise blood lactate was determined from a capillary blood sample drawn from an unwarmed fingertip. The sample was taken 5 minutes after the completion of exercise, stored, and then analyzed by a Komtron 640 automated lactate analyzer. Measurements of peak muscular strength were evaluated using a Cybex II Isokinetic Dynamometer. The muscle groups selected were the anterior thigh muscles (quadriceps), which were abbreviated RQ and LQ for r i g h t and l e f t quadriceps, and the posterior thigh muscles (hamstrings), which were abbreviated RH and LH for r i g h t and l e f t hamstrings. The muscle groups were recruited during extension and f l e x i o n of the knee. Three v e l o c i t -ies of movement were selected (30, 100, 180 deg*sec ^ ) . The v e l o c i t i e s of movement were progressively increased from 30 to 180 deg*sec ^ with each muscle group before the next muscle group was tested. B i o l o g i c a l age was determined on each of the subjects from ske l e t a l x-rays of the l e f t hand and wrist according to methods established by Greulich and Pyle (1959). TRAINING INTERVENTION Subjects i n the t r a i n i n g group had to undergo 16 weeks of intense anaerobic t r a i n i n g both on the ice and i n the laboratory. The subjects practised a minimum of twice per week during the period of t h i s study. Each practice was approximately 75 minutes i n length with 5 to 10 minutes devoted to high intensity skating d r i l l s designed to fatigue the anaerobic energy system. The subjects i n the t r a i n i n g group were scheduled to play at least 2 hockey games per week. One day per week was u t i l i z e d for high i n t e n s i t y i n t e r v a l t r a i n i n g i n the laboratory. Cycling f o r 45 seconds at a pedalling frequency of 80 r.p.m. was u t i l i z e d with a 1:2 work/rest r a t i o to simulate game-like conditions for th i s age group. Three sets of 3 s h i f t s was progressively increased to three sets of 5 s h i f t s over the period of t h i s study. Push-ups, chin-ups, sit-ups, and squat-thrusts were encouraged as a means of improving muscular strength and endurance. STATISTICAL ANALYSIS The data was analyzed using a multivariate analysis of variance. This was accomplished by using the BMD P4V computing programme, a general univariate and multivariate ANOVA (URWAS, 1983) at the Computing Centre of the University of B r i t i s h Columbia. The P4V i s a general purpose analysis of variance and covariance which does both univariate and multivariate analyses. S t a t i s t i c a l significance was accepted at an alpha l e v e l of 0.05. FIGURE 1 SCHEMATIC REPRESENTATION REPEAT SPRINT SKATE I I 0 • • 0 SPEED COMPONENT (54.87m) • SPEED-REPETITION COMPONENT (36.58m) D I l l RESULTS The physical characteristics of the subjects involved i n t h i s study are presented i n Table I. No s i g n i f i c a n t differences between the groups for chronological age, height, weight, or % body fa t were evident. During the 16 week period of t h i s study s i g n i f i c a n t increases i n height and weight were noted fo r subjects i n both the control and tra i n i n g groups (p ^ .01). The re s u l t s of the maturity assessment indicated that no differences existed between the groups with respect to t h e i r l e v e l of sk e l e t a l maturity. Both groups had a b i o l o g i c a l age which was approximately 7 months i n advance of t h e i r chronological age. Table II presents the laboratory metabolic variables which were calculated from either the WAnT or the AST. There were no s t a t i s t i c a l l y s i g n i f i c a n t differences between the groups for anaerobic power, anaerobic capacity, or blood lactate. I n i t i a l l y , the t r a i n i n g group showed a lower rate of fatigue (m*sec ^ ) on the WAnT and a longer running time to exhaustion on the AST than the control group (p - .05; p - .01, respectively). During the period of t h i s study s i g n i f i c a n t increases i n anaerobic power and rate of fatigue on the WAnT were noted for both groups (p - .05) Similar increases were noted for both groups on running time to exhaustion on the AST (p - .01). During t h i s same period of time the t r a i n i n g group demonstrated a greater rate of improvement on the AST than the control group (p - .01). Table I I I presents the on-ice metabolic variables which were calculated from the RSS. There were no s t a t i s t i c a l l y -s i g n i f i c a n t differences between the groups for anaerobic power, anaerobic capacity, speed % drop-off index, or blood la c t a t e . I n i t i a l l y , the t r a i n i n g group showed a lower rate of fatigue (m*sec "*") than the control group. Over the duration of t h i s study anaerobic capacity and blood lactate values of both groups for the RSS were found to be higher (p - .01; p - .05, respectively). Table IV presents the time analysis of the RSS. Each of the skating segments of the RSS has been represented i n t h i s table. The t r a i n i n g group showed a trend of being faster throughout each component of the RSS, both on the i n i t i a l and f i n a l testing sessions. The anterior thigh muscles (quadriceps) strength and power measurements are presented i n Table V. I n i t i a l l y , s t a t i s t i c a l analysis revealed that the t r a i n i n g group had greater strength and power than the control group. Both the r i g h t and l e f t limbs when evaluated at 30, 100, and 180 deg*sec ^ were s i g n i f i c a n t l y stronger i n the t r a i n i n g group (p - .01). During the period of t h i s study s i g n i f i c a n t increases i n a l l strength and power measurements were noted for both groups (p - .01). During t h i s same period of time the train i n g group demonstrated a greater rate of strength gain for only one muscle group, the RQ (30 deg*sec 1) (p - .05). The posterior thigh muscles (hamstrings) strength and power measurements are presented i n Table VI. I n i t i a l l y , the tr a i n i n g group had s i g n i f i c a n t l y greater strength and power than the control group. Both righ t and l e f t limbs when evaluated at 30, 100, and 180 deg*sec ^ were s i g n i f i c a n t l y stronger i n the tr a i n i n g group (p - .01). During the period of t h i s study s i g n i f i c a n t increases i n a l l strength and power measurements were noted for both groups (p - .01). During t h i s same period of time the trai n i n g group demonstrated a greater rate of strength gain of the RH (30 deg*sec _ 1), RH (100 deg*sec _ 1), and the LH (30 deg*sec~ 1) (p ^ .01; p <= .05; p <* .01). TABLE I MULTIVARIATE ANALYSIS OF VARIANCE FOR PHYSICAL CHARACTERISTICS CONTROL GROUP TRAINING GROUP F RATIO G m } p F RATIO p E R I 0 D F RATIO ^ x p ) Chronological Age (months) PRE 124.62 5.01 123.56 3.36 POST 128.62 5.01 127.56 3.36 0.06 0.00 0.00 Biological Age (months) MID 133.54 10.67 133.18 10.31 Height (cms) PRE 142.59 5.94 POST 143.88 6.14 141.80 6.71 142.94 7.15 0.30 81.76 0.14 Weight (kgs) PRE 36.06 6.28 POST 36.85 6.37 34.31 4.71 36.00 4.82 0.31 27.55 1.82 % Body Fat PRE. 21.69 5.68 POST 19.62 4.90 17.94 6.81 13.58 5.51 4.32 2.90 0.11 ** p = 0.01 * p = 0.05 TABLE II MULTIVARIATE ANALYSIS OF VARIANCE FOR LABORATORY METABOLIC VARIABLES CONTROL GROUP TRAINING GROUP F RATIO G R Q U p F RATIO p E R I 0 D F RATIO , Q x p^ Anaerobic Power W A n T PRE 242.62 36.25 238.82 39.93 0.13 6.08* 1.01 ( w a t t s ) POST 274.85 52.67 252.27 48.26 Anaerobic Capacity W A n T PRE 2895.15 516.11 3123.55 444.05 0.57 0.01 1.26 (joules) pQg.p 2 9 8 1 - 2 3 757.86 3011.73 588.71 Rate of Fatigue W A n T PRE 6.55 1.67 5.60 1.80 6.90 5.20 0.56 ( m* s e c ^ POST 8.22 2.24 6.27 1.67 Blood Lactate W A n T PRE 6.60 1.30 7.43 1.52 1.70 1.61 0.64 (mmol*l *) p o S T y > 2 6 1 > 3 9 7 _ 5 7 2 > 0 0 Anaerobic Speed Test PRE 41,46 15.20 62.67 17.94 10.45 10.88 9.04 (seconds) . 4 2 > 3 g 1 6 > 6 ? 3 4 > o y ** p * 0.01 *p = 0.05 TABLE III MULTIVARIATE ANALYSIS OF VARIANCE FOR ON-ICE METABOLIC VARIABLES CONTROL GROUP TRAINING GROUP F RATIO G R Q U p F RATIO p E R I 0 D F RATIO ^ x p-j Anaerobic Power ^ PRE 2305.31 364.05 2270.64 288.88 0.07 2.90 0.11 (watts) p Q S T 2 3 6 8 6 9 359 f 6 9 2309.91 268.36 Anaerobic Capacity ^ PRE 31534.62 5117.08 31327.36 4222.35 0.12 17.57 2.20 (joules) p Q S T 3 3 1 1 4 < 3 1 5529.60 34294.82 4408.78 Rate of Fatigue ^ PRE 0.92 0.27 0.71 0.25 6.13* 2.05 0.97 ( m * s e c -1 POST 0.90 0.32 0.57 0.21-Speed % Drop-off Index PRE 19.54 6.88 14.33 5.47 0.06 2.91 0.13 ^ POST 17.85 7.78 11.22 4.82 Blood Lactate PRE 6.74 0.76 8.16 1.52 3.84 5.53* 1.47 (mmol*l ) p ( ) S T y g 3 1 8 S J i m ** p ^ 0.01 * TABLE IV TIME ANALYSIS OF THE REPEAT SPRINT SKATE Speed Component (54.87 metres) (seconds) Speed-Repetition Component (36.57 metres) (seconds) Repetition Component (91.44 metres) (seconds) Total Time (4 x 91.44 metres) (seconds) CONTROL GROUP TRAINING GROUP PRE 9.66 9.56 POST 9.46 9.41 PRE 8.46 8.37 POST 7.91 7.50 PRE 18.12 17.93 POST 17.37 16.91 PRE 77.99 76.60 POST 76.13 72.43 TABLE V MULTIVARIATE ANALYSIS OF VARIANCE FOR ANTERIOR THIGH MUSCLES (QUADRICEPS) STRENGTH AND POWER MEASUREMENTS CONTROL GROUP TRAINING GROUP F RATIO G R Q U p F RATIO p E R I 0 D -1, ** ** RQ (30 deg*sec ) PRE 213.77 60.31 353.44 48.08 19.84 9.81 (N) (N) (N) (N) (N) (N) p ^ 0.01 *p = 0.05 POST 262.69 70.83 403.78 112.19 RQ (100 deg*sec~1) PRE 147.46 46.41 290.11 43.83 22.42** 9.19** POST 217.92 56.64 314.33 96.69 RQ (180 deg*sec~1) PRE 120.23 47.63 267.89 51.06 25.81** 8.83** POST 195.08 45.90 283.11 99.14 LQ (30 deg*sec"1) PRE 220.46 54.29 342.56 59.64 16.42** 16.67** POST 282.23 61.85 405.56 92.30 LQ (100 deg*sec~1) PRE 152.38 37.21 274.67 36.95 39.32** 33.22** POST 226.23 50.47 353.33 62.24 1 ft ft ft ft LQ (180 deg*sec ) PRE • 130.69 42.10 269.22 54.92 30.32 13.66 POST 199.62 53.84 297.00 71.24 TABLE VI MULTIVARIATE ANALYSIS OF VARIANCE FOR POSTERIOR THIGH MUSCLES (HAMSTRINGS) STRENGTH AND POWER MEASUREMENTS CONTROL GROUP TRAINING GROUP F RATIO G m j p F RATIO p E R I 0 D RH (30 deg*sec _ 1) PRE 144.69 24.91 190.78 40.33 13.82** 20.62** (N) (N) (N) (N) (N) (N) p ^ 0.01 *p * 0.05 POST 153.54 45.72 251.22 56.86 RH (100 deg*sec~1) PRE 110.92 26.95 168.00 42.83 15.01** 34.98** POST 135.15 41.97 228.44 56.00 RH (180 deg*sec - 1) PRE 95.08 22.07 168.89 57.15 17.54** 6.84** POST 119.92 28.62 180.11 39.24 -1 ** ** LH (30 deg*sec x) PRE 143.15 31.77 186.22 42.13 13.74 25.81 POST 162.62 47.26 259.11 92.30 1 s A A A A LH (100 deg*sec"1) PRE 118.08 33.11 157.56 22.17 13.13 20.45 POST 145.38 41.81 209.67 46.09 LH (180 deg*sec"1) PRE 95.23 33.68 163.00 39.37 17.40** 7.84** POST 131.69 38.22 181.00 39.17 IV DISCUSSION The physical characteristics of the subjects i n t h i s study suggest that t h i s group of prepubescent hockey players represents a r e l a t i v e l y homogeneous sample. The control group was s l i g h t l y older (124.62 vs 123.56 months), t a l l e r (142.59 vs 141.80 cms.), heavier (36.06 vs 34.31 kgs.), and had a higher percentage of body f a t (21.69 vs 17.94 %) than the t r a i n i n g group. However, only the body f a t was s i g n i f i c a n t l y d i f f e r e n t s t a t i s t i c a l l y . The results of the maturity assessment indicate that the subjects i n t h i s study are maturing at a normal rate. Since each of the group's b i o l o g i c a l age i s within 12 months of t h e i r chronological age they would be considered to be average with respect to t h e i r l e v e l of s k e l e t a l maturity. This i s i n agreement with the work of Bouchard et a l . (1969) and Malina (1982) who found young ice hockey players to approximate the average or be s l i g h t l y delayed i n t h e i r l e v e l of sk e l e t a l maturity. The physical characteristics of these groups are s i m i l a r to those of Cunningham et a l . (1976) who investigated the cardiopulmonary capacities of 10 year-old hockey players. Buti et a l . (1984), Cunningham and Paterson (1985), and Sadi et a l . (1984) have also found sim i l a r results i n prepubescent athletes involved i n tennis, running, and wrestling programmes, respectively. Krahenbuhl and Pangrazi (1983) investigated the characteristics associated with running performance i n young boys. Their subjects were shorter and l i g h t e r than the subjects i n t h i s study. The s t a t i s t i c a l l y s i g n i f i c a n t increases i n height and weight for both groups during the period of t h i s study i s i n agreement with the findings of Buti et a l . (1984). I n i t i a l l y , the t r a i n i n g group had a lower percentage of body f a t than the control group. During the period of this study a decrease i n the percentage of body f a t was noted for both groups. These changes probably r e s u l t from the effects of growth and maturation during the 16 weeks of thi s study. The effect of ice hockey and the related t r a i n i n g during t h i s time period may also have contributed to the physical and anthropometric changes i n these boys. The anaerobic power scores on the WAnT for the trai n i n g and control groups were 252.27 watts (7.06 watts*kg ^) and 274.85 watts (7.50 watts*kg "*"), respectively. These values are higher than those reported by Inbar and Bar-Or (1975) for 7-9 year-old boys of 159.8 watts (5.88 watts*kg _ 1). Similar results were found by Rhodes et a l . (1985) for 7-8 year-old hockey players of 241.77 watts (7.89 watts*kg "*"). Grodjinovsky et a l . (1980) reported values of 1902.0 kgm*min (310.78 watts) and 53.4 kgm*kg"1*min"1 (8.74 watts*kg _ 1) for a group of schoolchildren, while Tharp et a l . (1985) reported values of 228.77 kgm (448.57 watts) and 4.62 kgm*kg"1 (9.18 watts*kg ^) for 10-15 year-old track athletes. These values are higher than those reported i n the present study. The anaerobic power scores for the WAnT indicate that there were s i g n i f i c a n t increases by both groups i n anaerobic power during the 16 weeks of t h i s study. The rate of improvement by the two groups ranged from 5.61-13% which i s higher than the 3.1%-5.3% reported by Grodjinovsky et a l . (1980). Although no biochemical or h i s t o l o g i c a l measurements were taken during this study i t i s possible that these results indicate an enhancement of the a l a c t i c energy system within the musculature of these boys. This finding would be i n agreement with Eriksson (1972) who reported an increase i n the resting values of ATP, CP, and glycogen stores i n the musculature of 11-13 year-old children following an aerobic/ anaerobic t r a i n i n g programme. Karlsson (1971) and Karlsson et a l . (1972) found the stores of ATP and CP to increase by as much as 25% following an anaerobic t r a i n i n g regimen. Thorstensson et a l . (1975) found the a c t i v i t y l e v e l of CPK to increase by as much as 36% following a sprint tra i n i n g programme of 8 weeks. The anaerobic capacity scores during the WAnT for the t r a i n i n g and control groups were 3011.73 joules (83.73 joules*' kg *) and 2981.23 joules (80.78 joules*kg * ) , respectively. These values are s i m i l a r to those reported by Rhodes et a l . (1985) of 3307.57 joules (108.09 joules*kg~ 1). Higher values were reported by Grodjinovsky et a l . (1980) of 1607.4 kgm*min_1 (4377.45 -1 -1 -1 joules) and 45.2 kgm*kg *min (123.10 joules*kg ), Inbar and Bar-Or (1975) of 4463.0 joules (164.0 joules*kg~ 1), Mayers and Gutin (1979) of 4766 joules (149.4 joules*kg _ 1) for cross-country runners and 3883 joules (119.9 joules*kg 1) for control subjects, and Tharp et a l . (1985) of 1161.54 kgm (6326.47 joules) and 23.56 kgm*kg (129.51 joules*kg ). S t a t i s t i c a l l y s i g n i f i c a n t changes were not found for either group's anaerobic capacity. This i s unlike the changes reported by Grodjinovsky et a l . (1980) who demonstrated increases of 3.51-51 to be highly s i g n i f i c a n t . Grodjinovsky et a l . (1980) indicated that the WAnT was sensitive i n r e f l e c t i n g t r a i n i n g changes i n the anaerobic capacity of children, and thus, r e f l e c t e d a high rate of energy production by both the a l a c t i c (anaerobic power) and l a c t i c (anaerobic capacity) components of anaerobic metabolism. I t i s l i k e l y that the effect of the season of ice hockey, and the related t r a i n i n g , was to enhance the a l a c t i c energy system of the subjects. The i n t e r v a l cycling programme which was imposed on the t r a i n i n g group as part of the t r a i n i n g intervention was neither s p e c i f i c enough, or was of i n s u f f i c i e n t frequency, i n t e n s i t y , or duration to r e a l i z e a tr a i n i n g effect. The wide discrepancies which are reported f o r anaerobic power and capacity scores on the WAnT probably r e f l e c t s the range of resistance settings which are found i n the l i t e r a t u r e f o r studies involving children (.035-.075 grams*kg ^ body weight). The length of the test (25-40 seconds) may also contribute to the range of values reported for anaerobic power and capacity during the WAnT. During the 16 week period of t h i s study s i g n i f i c a n t increases i n the rate of fatigue were shown by both groups. The rate of fatigue i s very dependent upon the anaerobic power of the in d i v i d u a l . I f one ind i v i d u a l performs maximally i n the f i r s t 5 seconds of the WAnT, he w i l l have a higher power score and also a much higher rate of fatigue than one who works at a lower l e v e l of intensity i n the f i r s t 5 seconds. The increase i n the rate of fatigue shown, by both groups may then be explained by the increase i n anaerobic power shown by both groups during the period of t h i s study. The WAnT reported blood lactate values of 7.57 mmol*l ^ and 7.26 mmol*l ^ for the tr a i n i n g and control groups, respectively. Most of the reviewed l i t e r a t u r e does not report on blood lactates following the WAnT. However, Rhodes et a l . (1985) reported values of 10.25 mmol*l i n 7-8 year-old hockey players following a sim i l a r WAnT. The low correlations between anaerobic power or capacity on the WAnT when compared to blood lactates would suggest that blood lactates are not a good predictor of anaerobic power or capacity (performance), but are probably a good indicator of the int e n s i t y with which an exercise or a c t i v i t y has been performed. The running time to exhaustion on the AST was s i g n i f i c a n t l y higher for the tr a i n i n g group than for the control group. The 42.38 seconds for the control group i s si m i l a r to the 43.9 seconds reported for a control group by Mosher et a l . (1985) i n a study involving 10-11 year-old soccer players. The train i n g group's time of 84.00 seconds i s higher than the 62.3 seconds reported by Mosher et a l . (1985) for a group of trained soccer players. The rate of improvement by the t r a i n i n g group (341) was s i g n i f i c a n t l y greater than the rate of improvement by the control group (2%), but s i m i l a r to the findings of Mosher et a l . (1985) who reported a 211 improvement on the AST by soccer players following a 12 week train i n g period. I t i s possible that the subjects of the trai n i n g group were better runners than those i n the control group. They may have done more running during the course of the t r a i n i n g period, or perhaps they f e l t more comfortable running on a treadmill. The subjects i n the t r a i n i n g group were stronger and more powerful than those i n the control group. The tr a i n i n g intervention may also have contributed to the improve-ment i n running time to exhaustion on the AST. The subjects i n the t r a i n i n g group may have developed a greater "exercise tolerance" as a r e s u l t of the intervention. They were able to extend themselves both physi o l o g i c a l l y and psychologically on the AST, a test which had no fi x e d time component, while this was not possible on the WAnT which had fixed time components of 5 and 40 seconds. The anaerobic power scores on the RSS for the t r a i n i n g and control groups were 2309.91 watts (64.16 watts*kg *) and 2368.69 watts (64.28 watts*kg~ 1), respectively. Rhodes et a l . (1985) reported values of 1938.08 (55.47 watts*kg~ 1) for 7-8 y e a r - o l d i c e hockey p layers which are lower than those reported i n the present study. The l i t e r a t u r e reviews a number of s tudies which report the time needed to skate the f i r s t length o f the RSS. This time i s very important i n the c a l c u l a t i o n o f the anaerobic power o f the RSS (see appendix C ) . Reed et a l . (1979) reported t h i s time as 7.7 seconds f o r u n i v e r s i t y and J u n i o r "A" p l a y e r s , which i s 'slower than the times reported by Smith et a l . (1982) o f 7.4 seconds f o r se lec ted p r o f e s s i o n a l and J u n i o r "A" p layers and 7.2 seconds for the Canadian Olympic Hockey Team (1980). In an unpublished study Rhodes et a l . reported t h i s time as 7.81 seconds f o r a group o f 15-16 year-o l d hockey p l a y e r s . The subjects i n the present study covered the 54.87 metre d i s tance i n e i t h e r 9.41 seconds ( t r a i n i n g group) or 9.46 seconds ( contro l group). This i s s l i g h t l y f a s t e r than the time o f 9.73 seconds i t took for a group o f 7-8 y e a r - o l d hockey p layers to complete a s i m i l a r d i s tance (Rhodes et a l . , 1985). The anaerobic power scores i n d i c a t e that there were no s i g n i f i c a n t improvements by e i t h e r the t r a i n i n g group or the c o n t r o l group during the 16 weeks o f t h i s study. Thi s i s i n c o n f l i c t wi th the r e s u l t s o f the WAnT i n which there was s i g n i f i c a n t improvements i n anaerobic power o f both groups dur ing the study. I f we assume that the season of i c e hockey, and the r e l a t e d t r a i n i n g , was responsible f o r improving the a l a c t i c energy system, then the anaerobic power during the RSS should have also showed an improvement. I t i s p o s s i b l e that while the a l a c t i c energy system may have improved, the mechanical e f f i c i e n c y of skating may not have improved i n these boys to allow f o r an increase i n skating speed. This would account f o r the reported lack of improvement i n anaerobic power on the RSS. It i s possible that the season of i c e hockey, and the re l a t e d t r a i n i n g , may have also improved the l a c t i c a c i d energy system, which r e s u l t e d i n an increase i n anaerobic capacity during the RSS. The c a l c u l a t i o n of anaerobic capacity during the RSS i s very dependent on the maintenance of a high speed over the repeated t r i a l s of the t e s t . I f the l a c t i c a c i d energy system i s enhanced more energy can be produced f o r a longer period of time. This would enable an i n d i v i d u a l to maintain hi s speed f o r prolonged periods without f a t i g u i n g . This would r e s u l t i n a lower o v e r a l l time f o r the repeated t r i a l s and an increase i n the anaerobic capacity of the RSS. The time component of the RSS (72-76 seconds) i s almost twice that of the WAnT (40 seconds). This may be too short a period of time to make a c a l c u l a t i o n of anaerobic capacity f o r the WAnT. The on-ice training intervention which was imposed on the training group was neither specific enough, or was of insufficient frequency, intensity, or duration to realize a training effect. The rate of fatigue on the RSS was significantly lower for the training group than for the control group. This may have been due to the subjects in the training group being either stronger and more powerful, or perhaps more effi c i e n t skaters. The rate of fatigue for the training and control groups were 0.57 m*sec * and 0.90 m*sec \ respectively. Rhodes et a l . (1985) reported a value of 1.31 m*sec _ 1 for 7-8 year-old ice hockey players. The lower rate of fatigue demonstrated on the RSS in comparison to the WAnT is possibly due to the existence of a gliding phase in skating which is absent when cycling against a resistance. Since ice has a very low f r i c t i o n co-efficient momentum can be maintained during skating without a large increase in the rate of fatigue. The RSS reported blood lactate values of 8.57 mmol*l ^ and 7.83 mmol*l ^ for the training and control groups, respectively. This is lower than the 10.11 mmol*l 1 reported by Rhodes et a l . (1985) for 7-8 year-old ice hockey players following a similar RSS. Green (1978) reported higher lactate values i n university players following an intermittent skating test than was found i n the subjects of the present study. Green et a l . (1978) and Green (1979) reported values ranging from 2.92 to 6.16 mmol ^ of lactate during intermissions of hockey games. The s t a t i s t i c a l l y s i g n i f i c a n t increases i n blood lactates shown by both groups during the period of this study may p a r a l l e l the increases i n anaerobic capacity which were evident on the RSS. However, the low correlations between anaerobic power and capacity when compared to blood lactates would suggest that blood lactates are not a good predictor of anaerobic power or capacity. Since l a c t i c acid i s the end-product of anaerobic g l y c o l y s i s , and i t s maximal concentration i n muscle r e f l e c t s , i n part, the maximal rate of g l y c o l y s i s , lactates may indicate the i n t e n s i t y with which an exercise or a c t i v i t y has been performed. The increases i n a l l strength and power measurements which were noted for both the t r a i n i n g and control groups were probably due to the normal process of growth and maturation, although the effects of the season of ice hockey, and the related t r a i n i n g , may also have contributed. The greater rate of improvement shown by the tra i n i n g group i n only 4 out of 12 strength and power measurements indicates a random finding. The t r a i n i n g intervention was unsuccessful i n e l i c i t i n g the t r a i n i n g response f o r strength and power that was hypothesized for these boys. The peak muscular strength and power measurements of the muscles which cross the knee j o i n t were assessed largely because of t h e i r involvement i n the skating motion ( H a l l i w e l l , 1977). The values noted at slower speeds (30 deg*sec ^) indicate good strength development, but lower values at higher speeds (180 deg*sec "*") suggests that l i t t l e emphasis has been placed on the development of power and speed i n these athletes. This aspect of the tr a i n i n g of hockey players i s important not. only to skating but to shooting as w e l l . Power and speed-work are often neglected i n the on-ice and dryland t r a i n i n g of ice hockey players. V SUMMARY AND CONCLUSIONS There i s a paucity of information available on the physiological c h a r a c t e r i s t i c s of e l i t e prepubertal athletes. Considering the obvious importance of early success and involvement i n a t h l e t i c s for the eventual development and mastery of sport s k i l l s , the successful athlete who has not demonstrated an early a b i l i t y i n his sport i s obviously rare. The purpose of t h i s study was to evaluate the effects of a 16 week train i n g programme on selected on-ice and laboratory variables of 9-10 year-old boys involved i n a competitive ice hockey programme. Twenty-four subjects from two A-level representative teams were selected as subjects for t h i s study. Players from one team served as the t r a i n i n g group while players from the second team served as the age-matched control group. On-ice measures < of anaerobic capacity, anaerobic power, rate of fatigue, speed % drop-off index, and blood lactate were calculated from a RSS. Laboratory measures of anaerobic capacity, anaerobic power, rate of fatigue, and blood lactate were calculated from a WAnT which was extended to 40 seconds. The running time to exhaustion on an AST (11.67 kph @ 181 grade) was assessed as a measure of anaerobic endurance. Strength and power measurements of the quadricep and hamstring muscle groups were assessed at 30, 100, and 180 deg*sec \ At the beginning of thi s study several differences existed between the control and tra i n i n g groups. The traini n g group had a lower % of body f a t , a lower rate of fatigue on the WAnT and RSS, and a longer running time to exhaustion on the AST. The t r a i n i n g group was s i g n i f i c a n t l y stronger and more powerful than the control group i n a l l of the measured variables: RQ (30, 100, 180 deg*sec _ 1), LQ (30, 100, 180 deg*sec _ 1), RH (30, 100, 180 deg*sec _ 1), and the LH (30, 100, 180 deg*sec _ 1). Over the 16 week period of t h i s study both groups showed s i g n i f i c a n t increases i n a number of variables. Height and weight were the two physical c h a r a c t e r i s t i c s which increased s i g n i f i c a n t l y over the period of t h i s study. The WAnT e l i c i t e d increases i n anaerobic power and the rate of fatigue. The AST showed a longer running time to exhaustion. Increases i n anaerobic capacity and blood lactate were found following the RSS. During the period of t h i s study increases i n a l l strength and power measurements were noted for both groups. During the period of th i s study the t r a i n i n g group demonstrated a greater rate of improvement on several variables. The t r a i n i n g group showed a longer running time to exhaustion on the AST and a greater rate of improvement on 4 strength and power -1 -1 measurements: RQ (180 deg*sec ), RH (30, 100 deg*sec ), and the LH (30 deg*sec ^ ) . These changes may be attributed to the t r a i n i n g intervention which was imposed on the t r a i n i n g group. Conclusions The following conclusions can be reached: (1) During the 16 week period of th i s study growth and maturational processes resulted i n increases i n height and weight for subjects i n both the tr a i n i n g and control groups. (2) During the 16 week period of th i s study both groups showed increases i n anaerobic power and the rate of fatigue on the WAnT, and running time to exhaustion on the AST. (3) During the 16 week period of th i s study both groups showed increases i n anaerobic capacity and blood lactate values on the RSS. C.4) Although the tr a i n i n g group showed a trend toward being faster throughout each component of the RSS t h i s difference was not reflected i n the tr a i n i n g group having higher anaerobic capacity and power scores or a lower rate of fatigue. (5) During the 16 week period of t h i s study both groups showed increases i n a l l strength and power measurements. C6) The tr a i n i n g intervention was in e f f e c t i v e i n bringing about changes i n anaerobic capacity, anaerobic power, and rates of fatigue during either the RSS or the WAnT. The tra i n i n g group d i d , however, show s i g n i f i c a n t improvements over the control group on the AST, and on several strength and power measure-ments (RQ @ 30 deg*sec~ 1, RH @ 30 deg*sec~ 1, RH @ 100 deg*sec _ 1, and the LH @ 30 deg*sec _ 1). Recammendations for Further Research (1) The use of subjects who were not involved i n competitive ice hockey would a s s i s t i n determining whether the increases shown by both groups i n many of the variables over the period of t h i s study were due to growth and maturation or to the season of ice hockey, and the related t r a i n i n g . (2) The WAnT should be standardized to a s p e c i f i c length of time and a s p e c i f i c resistance setting f o r tests involving children. (3) Invasive research techniques should be u t i l i z e d to report on the q u a l i t a t i v e changes (biochemical and h i s t o l o g i c a l ) which occur i n children as a r e s u l t of exercise and conditioning programmes. (4) Training sessions of greater frequency and duration would be b e n e f i c i a l i n determining the effects of t r a i n i n g on the anaerobic performance of prepubertal children. REFERENCES Ayalon, A., Inbar, 0. and Bar-Or, 0. Relationships Among Measurements of Explosive Strength and Anaerobic Power. In: International Series on Sport Sciences, Biomechanics IV. Proceedings of the Fourth International Seminar on Biomechanics. R.C. Nelson and CA. Morehouse (eds). University Park Press. Baltimore. 1975, 1, 572-577. Bar-Or, 0. Characteristics and Applications of the Wingate Anaerobic Test. Presented at the 21st. 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Human Bio., 1972, 44, 195-214. diPrampero, P.E. and C e r r e t e l l i , P. Maximal Muscular Power (Aerobic and Anaerobic) i n African Natives. Ergonomics, 1969, 12, 51-59. Eriksson, B.O., Gollnick, P.D. and S a l t i n , B. The Effect of Physical Training on Muscle Enzyme A c t i v i t i e s and Fiber Composition i n 11 Year-old Boys. Acta. Paediatr. Belg., 1974, 28 (suppl.), 245-252. Eriksson, B.O. Physical Training, Oxygen Supply and Muscle Metabolism i n 11-to 15 Year-old Boys. Acta. Physiol. Scand., 1972, 384 (suppl.), 1-48. Eriksson, B.O. Cardiac Output During Exercise i n Pubertal Boys. Acta. Paediatr. Scand., 1971, 217 (suppl.), 53-55. Faria, I.E. Cardiovascular Response to Exercise as Influenced by Training of Various I n t e n s i t i e s . Res. Quart., 1970, 71, 44-50. Fox, E.L., Bartels, R.L., B i l l i n g s , C.E. et a l . Intensity and Distance of Interval Training Programs and Changes i n Aerobic Power. Med. S c i . Sports, 1973, 5, 18-22. Green, J . J . , Thomson, J.A., Daub, W.D. et a l . Fiber Composition, Fiber Size and Enzyme A c t i v i t i e s i n Vastus L a t e r a l i s of E l i t e Athletes Involved i n High Intensity Exercise. Eur. J . Appl. Physiol., 1979, 41, 109-117. Green, H.J. Glycogen Depletion Patterns During Continuous and Intermittent Ice Skating. Med. S c i . Sports, 1978, 10 (3), 183-187. Green, H.J., Daub, B.D., Painter, D.C. and Thomson, J.A. Glycogen Depletion Patterns During Ice Hockey Performance. Med. S c i . Sports, 1978, 10, (4), 289-293. Green, H.J. and Houston, M.E. Effect of a Season of Ice Hockey on Energy Capacities and Associated Functions. Med. S c i . Sports, 1975, 7 (4), 299-303. Green, H.J., Bishop, P., Houston, M.E. et a l . Energetics of Ice Hockey. Proceedings of the Sixth Annual Meeting of the Canadian Association of Sports Science. Vancouver. 1972 Greulich, W. and Pyle, S. Radiographic Atlas of Skeletal Development of the Hand and Wrist. Stanford Univeristy Press. Stanford, C a l i f o r n i a . 1959. Grodjinovsky, A., Inbar, 0., Dotan, R. and Bar-Or, 0. Training Effect on the Anaerobic Performance of Children as Measured by the Wingate Anaerobic Test. In: Children and Exercise IX. K. Berg and B.O. Eriksson (eds.). University Park Press. Baltimore. 1980, 139-145. 39. H a l l i w e l l , A.A. Determination of Muscle, Ligament, and A r t i c u l a r Forces at the Knee During a Simulated Skating Thrust. Masters Thesis, University of B r i t i s h Columbia, Vancouver, Canada. 1977. Inbar, 0. and Bar-Or, 0. The Effects of Intermittent Warm-up on 7-9 Year-old Boys. Eur. J . Appl. Physiol.. 1975, 34, 81-89. Karlsson, J . , Nordesjo, L., J o r f e l d t , L. and S a l t i n , B. Muscle Lactate, ATP and CP Levels During Exercise After Physical Training i n Man. J . Appl. Physiol., 1972, 33, 199-203. Katch, F.I., Michael, E.D. and Horvath, S.M. Estimation of Body Volume by Underwater Weighing: Description of a Simple Method. J. Appl. Physiol., 1967, 23, 811-813. Krahenbubl, G.S. and Pangrazi, R.P. Characteristics Associated with Running Performance i n Young Boys. Med. S c i . Sports E x e r c , 1983, 15 (6), 486-490. Malina, R.M. Physical Growth and Maturity Characteristics of Young Athletes. In: Children i n Sport. R.A. M a g i l l , M.J. Ash, F.L. Smoll (eds.). Human Kinetics Publishers, Champaign, I l l i n o i s . 1982. Mayers, N. and Gutin, B. Physiological Characteristics of E l i t e Prepubertal Cross-Country Runners. Med. S c i . Sports. 1979, 11, 172-176. Mosher, R.E., Rhodes, E.C., Wenger, H.A. and F i l s i n g e r , B. Interval Training: The Effects of a 12 Week Programme on E l i t e , Prepubertal Male Soccer Players. J . Sports Med., 1985, 25 (1-2), 5-9. Pollock, M.L., Cureton, T.K. and Greninger, L. Effects of Frequency of Training on Work Capacity, Cardiovascular Function and Body Composition of Adult Men. Med. S c i . Sports, 1969, 1, 70-74. Reed, A., Hansen, H., Cotton, C. et a l . Development and Validation of an On-Ice Hockey Fitness Test (published abstract). Can. J. Appl. Sport S c i . . 1979, 4 (4), 245. Rhodes, E.C., Potts, J.E. and Benicky, D.E. Prediction of Anaerobic Capacity i n Eight Year-Old Ice Hockey Players. Can. J . Appl. Sport S c i . . 1985 ( i n p r i n t ) . Roskamm, H. Optimum Patterns of Exercise for Healthy Adults. Can. Med. Assoc. J . . 1967, 96, 895-899. Sady, S.P., Thomson, W.H., Berg, K. and Savage, M. Physiological Characteristics of High-Ability Prepubescent Wrestlers. Med. S c i . Sports E x e r c , 1984, 16 (1), 72-76. Seliger, V., Kostka, V., Grusova, D., Kovac, J . , Machovcova, J . , Paver, M., Pribylova, A. and Urbankova, R. Energy Expenditure and Physical Fitness of Ice Hockey Players. Int. Z. Angew. Physiol., 1972, 30, 283-291. Sharkey, B.J. Intensity and Duration of Training and the Development of Cardiorespiratory Endurance. Med. S c i . Sports, 1970, 2, 197-202. Sharkey, B.J. and Holleman, J.P. Cardiorespiratory Adaptations to Training at Specified I n t e n s i t i e s . Res. Quart., 1967, 38, 698-704. Smith, J.D., Weriger, H.A., Quinney, H.A., Sexsmith, J.R. and Steadward, R.D.. Physiological P r o f i l e s of the Canadian Olympic Hockey Team (1980). Can. J . Appl. Sport S c i . , 1982, 7 (2), 142-146. Tharp, G.D., Newhouse, R.K., Uffelman, L., Thorland, W.G. and Johnson, G.O. Comparison of Sprint and Run Times With Performance on the Wingate Anaerobic Test. Res. Quart. Exerc. Sport, 1985, 56 (1), 73-76. Thorstensson, A., Sjodin, B. and Karlsson, J . Enzyme A c t i v i t i e s and Muscle Strength After "Sprint Training" i n Man. Acta Physiol. Scand., 1975, 94, 313-318. 41. APPENDIX A REVIEW OF LITERATURE INTRODUCTION "Physical conditioning i s the process by which exercise, repeated during weeks and months, induces morphologic and functional changes i n body tissues and systems. Mostly affected are the s k e l e t a l muscles, myocardium, blood vessels, adipose tiss u e , bones, ligaments, tendons, and the central nervous and endocrine systems" (Bar-Or, 1983). Research on the conditioning and t r a i n i n g of children has inherent methodologic obstacles. As with other age groups, studies should include an intervention programme and a longitudinal follow-up. In adults, changes i n function between pre- and post-intervention can be attributed with f a i r certainty to the condition-ing programme. This i s not the case with children or adolescents. Here, changes due to growth, development, and maturation often outweigh and mask those induced by the intervention (Bar-Or, 1983). Many of the physiological changes that r e s u l t from conditioning and t r a i n i n g regimens also take place i n the natural process of growth and maturation. I t w i l l be the purpose of t h i s review to present current research pertaining to the t r a i n a b i l i t y of prepubertal male athletes and i t s subsequent relationship with anaerobic capacity and power i n the sport of ice hockey. PHYSIOLOGICAL RESPONSES OF CHILDREN TO EXERCISE (1) Aerobic Power Research by several investigators including Andersen and Magel (1970), Andersen et a l . (1974), Astrand (1952), Bar-Or and Zwiren (1973), Bar-Or et a l . (1971), Chatterjee et a l . (1979), Cunningham and Paterson (1985), Ekblom (1969), Gaisl and Buchberger (1977), Hermansen and Oseid (1971), Ikai et a l . (1970), Kobayashii et a l . (1978), MacDougall et a l . (1979), Macek et a l . (1979), Mocellin (1975), Nagle et a l . (1977), Robinson (1938), Seliger (1970), Shephard et a l . (1969), and Thoren (1967) have shown that with the growth of the c h i l d there i s a p a r a l l e l increase i n his or her maximal aerobic power (expressed as maximal 0^ uptake). U n t i l age 12 values increase at the same rate i n both sexes, even though boys have higher values as early as age 5 (Yoshizawa et a l . , 1977) . Maximal aerobic power of boys continues to increase to about 18 years of age, but i t hardly develops beyond age 14 i n g i r l s . Maximal aerobic power i s strongly related to lean body mass (Burmeister et a l . , 1972; Eriksson and Thoren, 1978; Parizkova, 1968). When the maximal O2 uptake of adolescents of d i f f e r e n t ages, but of the same body weight or height i s compared, i t i s p o s i t i v e l y related to age (Sprynarova et a l . , 1978) . This suggests that maximal aerobic power depends somewhat on the maturity of the i n d i v i d u a l . Children have shorter uptake transients than do adults (Freedson et a l . , 1983; Macek and Vavra, 1980; Macek and Vavra, 1980; Robinson, 1938). The 0 2 d e f i c i t of 10- to 11 year-old boys was found to be smaller than among young adults. Even more pronounced was the high rate at which boys increased t h e i r uptake when compared with adults. These boys reached 55% of t h e i r f i n a l C^ uptake within 30 seconds and a steady state w i t h i n 2 minutes. The adults reached only 33% of t h e i r f i n a l uptake within the f i r s t 30 seconds and required some 3-4 minutes to reach a steady state (Macek and Vavra, 1980). Bar-Or (1983) suggested that due to t h e i r shorter 0^ transients children may not need to depend as heavily on anaerobic pathways for t h e i r energy requirements. He also suggested that these shorter transients may be compensatory for t h e i r low g l y c o l y t i c capacity. Cumming (1978) suggested that the shorter transients i n children could be a r e f l e c t i o n of a smaller body surface area and the re s u l t i n g shorter c i r c u l a t i o n time. Among adults who undergo an aerobic conditioning programme there i s an age-related trend; the younger the i n d i v i d u a l , the more trainable he or she i s ( S a l t i n , 1969). This does not appear to be the case with children. In some studies adolescents and children responded i n a predictable manner to either general conditioning or s p e c i f i c t r a i n i n g regimens (Bannister, 1965; Dotan et a l , 1982; Ekblom, 1969; Grodjinovsky and Bar-Or, 1983; Shephard et a l . , 1977; Sprynarova et a l . , 1978; Weber et a l . , 1976). There i s , however, growing evidence to suggest that aerobic t r a i n a b i l i t y i n prepubescents, p a r t i c u l a r l y i n those less than 10 years of age, i s lower than expected, even though t h e i r a t h l e t i c performance may improve (Andersen and Froberg, 1980; Bar-Or, 1983; Bar-Or and Zwiren, 1973; Daniels and Oldridge, 1971; Daniels et a l . , 1978; G i l l i a m and Freedson, 1980; Kobayashi et a l . , 1978; Schmucker and Hollmann, 1974; Shephard et a l . , 1977; Stewart and Gutin, 1976; Yoshida et a l . , 1980). Several studies involving prepubescent children have shown that following aerobic t r a i n i n g programmes the children markedly improved t h e i r running performance without an increase i n maximal aerobic power (Bar-Or and Zwiren, 1973; Mocellin and Wasmund, 1973; Stewart and Gutin, 1976; Yoshida et a l . , 1980). Daniels et a l . (1978) suggested that an improvement i n running performance without a concomitant increase i n maximal 0^ uptake may be explained by an increase i n the e f f i c i e n c y or economy of movement. Several authors suggest that the use of maximal 0)^ uptake i s not a sensitive indicator to show changes i n maximal aerobic power of prepubescent children (Cumming et a l . , 1967; Mayers and Gutin, 1979; Rost et a l . , 1978; Schmucker et a l . , 1977). In some studies, which involve the use of a control group(s), another possible explanation for the apparent lack of t r a i n i n g effects i n prepubescents could be the high habitual a c t i v i t y l e v e l of the "controls" (Bar-Or, 1983; Cumming et a l . , 1969; ; Hamilton and Andrew, 1976). Kobayashi et a l . (1978) suggested that the effectiveness of aerobic conditioning programmes was greatest at, or around, peak height v e l o c i t y (PHV). Andersen and Froberg (1980) could not i d e n t i f y such a c r i t i c a l stage i n aerobic t r a i n a b i l i t y . The c o n f l i c t i n g results from these studies leave us unable to id e n t i f y a concise developmental stage where aerobic t r a i n a b i l i t y reaches that of young adults. (2) Anaerobic Capacity and Power The a b i l i t y to perform short supramaximal tasks i s dependent on, among other factors, anaerobic power (the alactacid component of the oxygen d e f i c i t ) and anaerobic capacity (the l a c t a c i d component of the oxygen d e f i c i t ) (Margaria, 1967; Houston and Thomson, 1977). The a b i l i t y of children to perform anaerobic-type a c t i v i t i e s i s d i s t i n c t l y lower than that of adolescents and adults (Davies et a l . , 1972; diPrampero and Cer r e t e l l y , 1969). Performance expressed i n absolute units of power'(watts or joules) i s p o s i t i v e l y related to age (Eriksson, 1971). When standardized for body weight (watts*kg ^ or joules*kg ^ ) , however, the power produced by an 8 year-old boy i s s t i l l only 70% of that generated by an 11 year-old boy (Eriksson, 1971). Very few studies have employed prepubertal subjects i n an i n t e r v a l t r a i n i n g programme which was designed to e l i c i t changes i n anaerobic performance. Mosher et a l . (1985) studied the effects of a 12 week i n t e r v a l t r a i n i n g programme on pre-pubertal soccer players. These 10 and 11 year-old boys showed a s i g n i f i c a n t improvement on an Anaerobic Speed Test (AST) (11.67 kph @ 18% grade), 1 mile run, and % drop-off index on a repeat sprint of 40 yards. The authors suggested that t h e i r results indicate that soccer players, and perhaps a l l boys of t h i s age, can increase both anaerobic and aerobic f i t n e s s through p a r t i c i p a t i o n i n high i n t e n s i t y i n t e r v a l t r a i n i n g programmes. The changes e l i c i t e d i n t h i s study are p a r t i c u l a r l y interesting when compared to a number of studies (Bar-Or and Zwiren, 1973; Gaisl and Buchburger, 1980; Wasmund and Mocellin, 1972) that have suggested 11 years of age to be the lower l i m i t at which there i s any l i k e l i -hood of achieving any tr a i n i n g effects. Many studies which have investigated the t r a i n i n g effects on the anaerobic performance of children have u t i l i z e d the Wingate Anaerobic Test (WAnT). The r e l i a b i l i t y , v a l i d i t y , and the sens-i t i v i t y of the WAnT has been supported by investigations conducted mainly by researchers at the Wingate I n s t i t u t e i n Israel (Ayalon et a l . , 1985; Bar-Or, 1978; Grodjinovsky et a l . , 1980; Inbar and Bar-Or, 1975). Bar-Or and Inbar (1978) concluded that the WAnT was a v a l i d predictor of sprinting a b i l i t y i n non-athletic children. The relationship between the WAnT and run times (40, 300, 600 metres) i n 35 non-athletic boys (x age = 12 - 1.7 years) was examined. Moderate relationships were found between 30 second power outputs (anaerobic capacity) and run times. More exacting relationships were found between 5 second power outputs (anaerobic power) and run times. Tharp et a l . (1985) conducted a study with young male track athletes (x age = 13.3 - 1.2 years) and found WAnT scores f o r anaerobic capacity and power were only moderately correlated with 50 and 600 yard run times. P a r t i a l correlations between these variables were found to be lower when age adjusted and higher when adjusted for body weight. They concluded that the WAnT i s only, a moderate predictor of sprint or run times, but became a stronger predictor when WAnT scores were adjusted for body weight. Cumming (1972) used a prototype of the WAnT to examine anaerobic power i n 12-to 17 year-old children at a summer a t h l e t i c camp. He observed the relationship between a bicycle ergometer test of power and run times (100, 440, 880 yards, and 2 miles). His results indicated that the strength of the relationship between anaerobic power and run times decreased as the distance of the run increased. Grodjinovsky et a l . (1980) designed a study to determine whether or not the WAnT was sensitive to changes i n anaerobic performance of 11-to 13 year-old boys following a 6 week tra i n i n g regimen. Anaerobic capacity and power showed an increase of approximately 3.5% to 5% following the t r a i n i n g period. This 48. study also provided some interesting findings on the r e l a t i o n -ship between body weight and age to WAnT scores. The WAnT becomes a strong predictor of sprint and run times when i t i s adjusted for body weight. P a r t i a l correlations adjusting for age or weight indicate that weight remains highly correlated with anaerobic capacity and power when the effect of age i s removed, but age loses much of i t s corre l a t i o n with anaerobic capacity and power when adjusted for weight. (3) Biochemical Considerations , Children, and Exercise Davies (1971) and Davies et a l . (1972) suggested that differences i n maximal aerobic power can be accounted for by the mass of active muscle tissue. This i s not so with anaerobic capacity and power. The markedly lower anaerobic c a p a b i l i t i e s of the young c h i l d r e f l e c t s , to a great extent, a q u a l i t a t i v e deficiency i n his muscle, or recruitment of motor units which innervate the muscle (Bar-Or, 1983). Karlsson (1971) and Karlsson et a l . (1972) found that the stores of ATP and CP increased by as much as 25% following an anaerobic t r a i n i n g programme involving adults. Thorstensson et a l . (1975) found that the a c t i v i t y l e v e l of Creatine Phosphokinase (CPK) increased by 36% following a sprint t r a i n i n g programme of 8 weeks. Karlsson et a l . (1972) using an adult population showed an increase i n some g l y c o l y t i c enzymes following an anaerobic t r a i n i n g programme. Eriksson (1972) investigated the effects of a combined aerobic and 49. anaerobic t r a i n i n g regimen on 11-13 year-old children and found there was an increase i n resting values of muscle ATP, CP, and glycogen, and that glycogen depletion was enhanced with exercise. The primary age-related difference i s i n g l y c o l y t i c capacity. Resting concentration of glycogen, and especially the rate of i t s anaerobic u t i l i z a t i o n , are lower i n the c h i l d , who i s therefore at a functional disadvantage when performing strenuous a c t i v i t i e s that l a s t 10 to 60 seconds (Bar-Or, 1983; Eriksson et a l . , 1980; Eriksson et a l . , 1974; Karlsson, 1971). One way of assessing glycogen u t i l i z a t i o n i s by measuring lactate concentration i n the blood or, preferably, i n the muscle. Studies by Astrand (1952), Blimkie et a l . (1978), Eriksson (1980), Eriksson et a l . (1974), Eriksson et a l . (1971), Karlsson (1971), Matejkova et a l . (1980), and Moody et a l . (1972) have shown that maximal lactate levels i n the blood and i n muscle are lower i n children than i n older subjects. Studies on rats have shown that lactate production i s related to the l e v e l of c i r c u l a t i n g testost-erone (Krotkiewski et a l . , 1980). Karlsson (1971) suggested that the a b i l i t y of boys to produce lactate during maximal exercise depends on t h e i r sexual maturity. The rate of glycolysis i s also l i m i t e d by the a c t i v i t y of such enzymes as phosphorylase, pyruvate dehydrogenase, and phospho-fructokinase (PFK). Eriksson et a l . (1974) and Eriksson (1972) found PFK to be less active i n the muscle c e l l s of 11-to 13 year-old boys than i n young adults. An additional indicator of anaerobic capacity i s the degree of acidosis at which the muscle c e l l can function. Some trained adult athletes can push themselves to exercising at a r t e r i a l blood pH as low as 6.80 (Kindermann et a l , , 1975), which i s equivalent to a pH of 6.60 or less i n active muscle c e l l s (Bar-Or, 1983). Untrained individuals can seldom sustain exercise when t h e i r a r t e r i a l blood pH reaches 7.20 (Bar-Or, 1983). Gai s l and Buchberger (1977), Kindermann et a l . (1975), and Matejkova et a l . (1980) have shown that children do not reach as high levels of acidosis as do adolescents or young adults. (4) Skeletal Muscle Adaptation to Exercise Being the effector organ of body movement, the s k e l e t a l muscle i s expected to undergo a major adaptation to conditioning. Since the advent of a needle biopsy technique i n the early 1960's, much research has been done on adults, demonstrating that h i s t o l o g i c a l and biochemical changes do occur. Due to e t h i c a l considerations data on adolescents i s l i m i t e d . Bar-Or (1983) indicated that children show a s i m i l a r pattern of adaptation to that of adults. Skeletal muscle hypertrophy, and possibly hyperplasia, occur i n the chronically active muscles of adults. Fournier et a l . (1982) and Jacobs et a l . (1982) found that among adolescents undergoing an endurance t r a i n i n g programme, hypertrophy, but not hyperplasia, occured. Fournier et a l . (1982) found that a sprint t r a i n i n g programme resulted i n neither hypertrophy or hyperplasia. There i s no evidence to support the hypothesis that a change i n f i b e r type d i s t r i b u t i o n w i l l r e s u l t from t r a i n i n g (Eriksson et a l . , 1974; Fournier et a l . , 1982; Jacobs et a l . , 1982). An increase i n muscle c a p i l l a r i z a t i o n and the development of c o l l a t e r a l c i r c u l a t i o n to sk e l e t a l muscle has not yet been investigated i n children (Bar-Or, 1983). The t r a i n a b i l i t y of muscle strength i n children has yielded inconclusive r e s u l t s . Rohmert (1968) found the muscle strength of 8 year-old g i r l s and boys to be somewhat more trainable than among adults who were given the same r e l a t i v e t r a i n i n g stimulus. Nielson et a l . (1980) indicated that over a 5 week tr a i n i n g period 7 - 13.4 year-old g i r l s had a greater r e l a t i v e increase i n isometric strength than did 13.5 to 19 year-old g i r l s . In contrast to t h i s data Vrijens (1978) observed that postpubescent boys had a greater response to a strength t r a i n i n g programme than did prepubescent boys. In a study by Hettinger (1961) adolescents of both sexes had a lesser improvement i n isometric strength than did young adults. (5) Conditioning, Body Composition, and Children When conditioning regimens are such that the cummulative energy expenditure i s high or the e f f o r t i s intense, changes i n body composition may occur. The anabolic effect of exercise induces an increase i n the lean body mass of the i n d i v i d u a l , while the increased energy expenditure serves to reduce the mass of the adipose tissue. The o v e r a l l r e s u l t i s a r e l a t i v e increase i n lean body mass and a decrease i n adiposity. Goode et a l . (1976), Moody et a l . (1972), Parizkova (1977), and Parizkova (1968) indicated that following physical fitness programmes subjects increased t h e i r lean body mass and decreased t h e i r adiposity. Authors such as Berg and Bjure (1974), Clarke and Vaccaro (1979), Glick and Kaufmann (1976), and Sprynarova et a l . (1978) have f a i l e d to f i n d s i m i l a r changes. The main reason for such c o n f l i c t i n g results i s that changes i n body mass and composition depend also on factors other than energy expenditure. Calorie intake and the composition of the consumed food i s the primary n u t r i t i o n a l consideration. An additonal factor to consider i s the confounding effect of growth and maturation. Thus, while a certain conditioning programme e f f e c t i v e l y modifies body composition, the effects may be masked and even counteracted by growth and maturation related changes, as we l l as by changing dietary-habits. Glick and Kaufmann (1976) and Moody et a l . (1972) reported that obese children seem to respond to exercise regimens with greater changes i n body composition that do non-obese children. ICE HOCKEY Research by Green et a l . (1978), Green and Houston (1975), and Green et a l . (.1972) has attempted to define the acute stress placed on the various systems of ice hockey players, and to correlate t h i s stress with the diff e r e n t energy c a p a b i l i t i e s of the players. Due to the intermittent nature of the game wide variations e x i s t i n skating speed, durations of play, and recovery periods. Mich of the actual skating i s explosive i n nature, short bursts of skating being followed by a period of coasting. The actual amount of playing time during a game varies from 18-24 minutes, depending on the pos i t i o n which i s played (Green and Houston, 1975; Seliger et a l . , 1972). This i s divided into approximately 17 separate s h i f t s on the i c e , each s h i f t averaging 75-85 seconds, which are separated by 3-4 minutes of recovery time (Green and Houston, 1975). During an indi v i d u a l s h i f t there may be 2 or 3 stoppages which provide only 35-40 seconds of continuous action interrupted by 25-30 second stoppages i n play (Green and Houston, 1975). Seliger et a l . (1972) estimated the t o t a l energy expenditure that a player would expend i n a game to be approximately 820 calor i e s (450-1170 c a l o r i e s ) . Time-motion analyses have shown that the t o t a l length of ice which a player would cover during a game to be approximately 5160 metres (4860-5620 metres) (Seliger et a l . , 1972). This corresponds to the length of ice which an e l i t e performer would cover during a game to be between 6400-7200 metres. Investigations by Seliger (1967) showed that younger hockey players cover approximately 2360 metres during a game. Telemetered measures of heart rate, oxygen consumption (during actual play and recovery periods), and between-period determination of blood lactate have tended to support the importance of both the aerobic and anaerobic systems to energy delivery i n hockey players (Green, 1978; Green et a l . , 1978; Green and Houston, 1975; Seliger et a l . , 1972; Seliger, 1968). Seliger (1972) reported that during a game approximately 69% of the energy expenditure i s covered by anaerobic metabolism. Green and Houston (1975) observed the effects of a season of ice hockey on 16-20 year-old hockey players. They concluded that over the 5 month t r a i n i n g period e s s e n t i a l l y no change i n aerobic power occured. The author's reasoned that the lack of improvement i n aerobic power could r e s u l t from an i n a b i l i t y of the aerobic system to respond to the tr a i n i n g programme, lack of stress necessary to r e a l i z e a change i n the aerobic system, or the i n a b i l i t y of treadmill running to detect improvements re a l i z e d as a resul t of ice skating. Daub et a l . (1983) reported that high i n t e n s i t y ice hockey tr a i n i n g f a i l e d to e l i c i t any a l t e r a t i o n i n maximal oxygen uptake, maximum heart rate, and maximum v e n t i l a t i o n , either during cycling or ice skating. This finding i s consistent with that of Hedberg and Wilson (1975), Green et a l . (1979), Seliger et a l . (1972), Seliger (1967), and Yokobori (1964). The hockey tr a i n i n g appeared to modify selected physiological responses to prolonged ice skating but not to prolonged cycling. Green (1978) observed the glycogen depletion patterns during continuous and intermittent ice skating. The results from t h i s study demonstrated the importance of the vastus l a t e r a l i s muscle i n supramaximal bouts of ice skating, and that the a c t i v i t y of ice skating produces a pattern of glycogen depletion which i s si m i l a r to that found following c y c l i n g . I t was noted that the selective depletion of di f f e r e n t muscle fibers was dependent upon the i n t e n s i t y of work which was done. Daub et a l . (1983) investigated the effects of a supplementary t r a i n i n g programme of low i n t e n s i t y cycling on ice hockey performance. The cycling programme modified the cardiovascular response to submaximal cycling only, and did not influence the response to submaximal or maximal i c e skating. The authors suggested that the r e l a t i v e work load was lower during prolonged cycling than during prolonged skating and thus did not e l i c i t changes i n the skating parameters. Smith et a l . (1982) monitored the on-ice and laboratory performance of the Canadian Olympic Hockey Team (1980). Among the selected physiological measurements which were evaluated were maximum aerobic power, muscular strength and power, body composition, and an on-ice test of skating power. The maximum aerobic power for t h i s group was found to be lower than that reported for other e l i t e teams (Green et a l . , 1978; Rusko et a l . , 1978), but simi l a r to others (Green et a l . , 1979; Seliger et a l . , 1972). Knee and hip flexion/extension and shoulder abduction/adduction were assessed because they are largely involved i n the hockey s k i l l s of skating and shooting (Smith et a l . , 1982). The high values reported for knee extension at slow speeds of movement (30 deg*sec "*") i n relationship to other athletes (Thorstensson et a l . , 1977) suggest good strength development, but lower values at higher speeds of movement (180 deg*sec "'") i n relationship to other athletes (Thorstensson et a l . , 1977) suggest l i t t l e emphasis has been placed on the development of power at high speeds i n these athletes. Smith et a l . (1982) used the on-ice test of Reed et a l . (1979) to assess the skating power of the Olympic Hockey Team and t h e i r a b i l i t y to repeat high speed intervals with short rest periods. The Olympic Team showed faster speed over 54.87 metres, but a greater time drop-off with s i x repeats of 91.45 metres when compared to professional and junior players (Reed et a l . , 1979). Smith et a l . (1982) postulated that the faster speeds over 54.87 metres contributed to the greater time drop-offs over repeated t r i a l s . In the early years of research into the involvement of youth i n the sport of ice hockey many investigators were interested i n the a q u i s i t i o n of s k i l l s by the young players (Doroschuk and Marcotte, 1965). In more recent years there has been a concerted e f f o r t to describe the physiological characteristics of young, e l i t e ice hockey players. This was done to assess t h e i r c a p a b i l i t i e s , to r e f l e c t on past t r a i n i n g programmes and, more recently, to prescribe new t r a i n i n g programmes. Smith et a l . (1982) suggest that the data which i s gathered should provide a baseline from which comparisons with other athletes can be made, strengths and weaknesses assessed, and s p e c i f i c t r a i n i n g prescriptions formulated. McNab (1979) published the results from a 5 year longitudinal study of 15 boys involved i n an intense ice hockey programme. The study was i n i t i a t e d when the boys were 8 years of age and continued up to and including 12 years of age. Each year evaluations of skating and puck control s k i l l s were made. In addition, annual measurements of height, weight, grip strength, physical work capacity (PWC^Q) , and the CAPHER fitness-performance items were taken. Results of the skating and puck control tests indicated learning curves which, while t y p i c a l i n nature, demonstrated extremely high levels of achievement for boys of this age (unpublished data by Hansen; McNab, 1979). Blimkie and Cunningham (.1978) and Cunningham (1979) investigated the maximal aerobic power of young hockey players and observed that young highly motivated boys found i t d i f f i c u l t to develop high levels of blood lactate and to exercise at maximal levels so that a plateau i n VC^ i s reached prematurely. In a study by Cunningham (1979) blood levels following tests of aerobic power were found to be 8.6 mmol*l * at age 11, while t h i s value gradually increased to 10.5 mmol*l ^ at age 16. DEVELOPMENT AND VALIDATION OF AN ANAEROBIC SKATING TEST FOR ELITE ICE HOCKEY PLAYERS In an unpublished study the v a l i d i t y and r e l i a b i l i t y of two on-ice tests were evaluated by comparing on-ice blood lactates and performance measures with the same variables generated i n the laboratory on an extended (40 second) WAnT. The two on-ice tests which were used i n t h i s study included the Sargeant Anaerobic Skate (SAS) and the Repeat Sprint Skate (RSS) which was developed by Reed et a l . (1979). The three performance measures which were analyzed were anaerobic capacity, anaerobic power, and the rate of fatigue. The mean scores for anaerobic capacity and power which were achieved on the SAS were s i g n i f i c a n t l y greater than those on the extended WAnT. Astrand and Rodahl (1977), Brouha (1945), and Fox (1975) have shown that individuals who are trained for heavy exercise of a par t i c u l a r type (skating) are able to do more r e l a t i v e work i n that a c t i v i t y than when performing other forms of exercise (cycling). The mean scores for the rate of fatigue showed that subjects fatigued to a greater, r e l a t i v e degree on the WAnT than on the SAS. Following the SAS a peak value of 10.69 mmol*l lactate was measured. This value i s s i m i l a r to that of the hockey players reported by Green (1978) following 5 repeats of 60 seconds skating at 120% of th e i r maximum aerobic power. Green (1979) and Green et a l . (1978) reported values ranging from 2.92 to 6.16 mmol*l * lactate during intermissions of actual hockey games. Green (1978) f e l t that the blood samples i n these experiments gave some ind i c a t i o n of the contribution of glycolysis to the t o t a l energy supply, and that values were s i g n i f i c a n t l y elevated from resting l e v e l s . SAS performance measures when correlated against the WAnT indicated i t was a v a l i d measure of anaerobic capacity, but not of anaerobic power or fatigue. The SAS was found to be reproduc-i b l e and r e l i a b l e . The mean scores for anaerobic capacity and power which were achieved on the RSS were s i g n i f i c a n t l y greater than those on the extended WAnT. Anaerobic power scores were derived from the time to skate the f i r s t length of each t r i a l . The mean times recorded i n t h i s study are simi l a r to that reported by Reed et a l . (1979) and Smith et a l . (1982). The mean scores for the rate of fatigue showed that subjects fatigued to a greater, r e l a t i v e degree on the WAnT than on the RSS. 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APPENDIX B DEFINITION AND CALCULATION OF ANAEROBIC CAPACITY ANAEROBIC CAPACITY - the maximal amount of work that can be produced u t i l i z i n g anaerobic metabolism [both the a l a c t i c and l a c t i c acid components of anaerobic metabolism are used i n the determination of this value). REPEAT SPRINT SKATE Anaerobic Capacity = subject's wt. (kgs) * D. skated (365.80 m) time (seconds) kgm*sec * 60 = kgm*min kgm*min * - 6.12 = watts watts * .06 = joules WINGATE ANAEROBIC TEST Anaerobic Capacity = t o t a l revs. (40 sec) * circum (m) * res (kgm) time (40 seconds) kgm*sec * 60 = kgm*min kgm*min ^ - 6.12 = watts watts * .06 = joules APPENDIX C DEFINITION AND CALCULATION OF ANAEROBIC POWER ANAEROBIC POWER - the maximal amount of work that can be produced i n a fixed period of time (the a l a c t i c component of anaerobic metabolism i s primarily used i n the determination of this value). REPEAT SPRINT SKATE Anaerobic Power = subject's wt. (legs) * D. skated (54.87 m) time (seconds) = kgm*sec * * 60 = kgm*min ^ kgm*min 6.12 = watts WINGATE ANAEROBIC TEST t o t a l revs. (5 sec) * circum (m) * res (kgm) . • _^ _^ Anaerobic Power = = kgm*sec * 60 = kgm*min time (5 seconds) _^ kgm*min - 6.12 = watts APPENDIX D DEFINITION AND CALCULATION OF RATE OF FATIGUE RATE OF FATIGUE - a reduction i n the effic i e n c y of movement (distance covered) that i s generated over a period of time and a series of repeated t r i a l s . REPEAT SPRINT SKATE t r i a l D. (54.87 m) t r i a l D. (54.87 m) Rate of Fatigue = fastest t r i a l time (sec) slowest t r i a l time (sec) WINGATE ANAEROBIC TEST (highest 5 sec. revs) - (lowest 5 sec. revs) * circum (m) Rate of Fatigue = time (5 seconds) APPENDIX E PROTOCOL AND CONSENT FORM TITLE OF RESEARCH: The E f f e c t s o f T r a i n i n g on Anaerobic C a p a c i t y , Anaerobic Power, and Rate o f Fat igue i n Pre-puber ta l E l i t e Ice Hockey P l a y e r s . Researchers: Dr . B . C . Rhodes, J . P o t t s . Dr . 3. Ho, Dr. R. L l o y d -Smith. Dr. R. Mosher, and Dr. J . Taunton. The purpose o f t h i s study i s to i n v e s t i g a t e the e f f e c t s o f t r a i n i n g on 9 and 10 y e a r - o l d represen ta t ive hockey p l a y e r s . T h i s research w i l l r e q u i r e your son to p a r t i c i p a t e i n a s e r i e s o f t e s t i n g procedures i n November, and a repeat o f these tes t s 16 weeks l a t e r i n March. These t e s t i n g procedures w i l l be d i v i d e d i n t o an o n - i c e component and a l a b o r a t o r y component. The o n - i c e t es t s w i l l inc lude a Repeat S p r i n t Skate i n which each subject w i l l be r e q u i r e d to skate a d i s tance o f 91.45 metres (500') on 4 separate occasions ( t r i a l s ) . The t o t a l time involvement of t h i s t e s t i s two minutes and twenty seconds. Fo l lowing t h i s t e s t your son w i l l be asked to s i t down and r e s t f o r 5 minutes at which time a smal l q u a n t i t y o f b lood (25 m i c r o - l i t r e s ) w i l l be removed f o r ana lys i s by a f i n g e r t i p p r i c k method. A p h y s i c i a n ( e i t h e r Dr . Taunton' or Dr. Lloyd-Smith) w i l l supervise the removal o f b lood from s u b j e c t s . Tne l a b o r a t o r y tes t s w i l l c o n s i s t of tak ing an i n i t i a l set of s k e l e t a l x -rays of the l e f t w r i s t and hand o f your son. The amount • o f r a d i a t i o n your son w i l l be exposed to w i l l be minimal (100 mRads). The s k e l e t a l x -rays w i l l g ive the researchers the l e v e l o f s k e l e t a l development (maturation) o f your c h i l d . T h i s in format ion may then be used to e x p l a i n any r e s u l t s that may be a t t r i b u t e d to "ear ly" vs . " late" maturat ion . The s u p e r v i s i o n and a n a l y s i s o f the x -rays w i l l be done by a r a d i o l o g i s t (Dr. B r i a n Ho, U . B . C . Department o f Radio logy) . A b i c y c l e ergometer tes t w i l l a l so be adminis tered . Your son w i l l be asked to pedal a b i c y c l e as f a s t as he can agains t a r e s i s t a n c e that has been predetermined by h i s body weight. The durat ion of t h i s t es t i s 40 seconds. Fo l lowing the t e s t your son w i l l be asked to s i t and res t for 5 minutes a f t e r which h i s f i n g e r w i l l be p r i c k e d and a smal l quant i ty o f b lood removed (25 micro-l i t r e s ) . Measures o f peak muscular s trength w i l l then be determined on muscle groups o f the th igh and l e g . The muscular s trength w i l l be assessed at three v e l o c i t i e s of movement (30, 100, 180 deg*sec- l ) so as to assess both the i n t e g r i t y and dynamic c a p a b i l i t i e s o f the involved j o i n t s . The f i n a l laboratory measure i s a h y d r o s t a t i c weighing technique which w i l l be used to evaluate your son's body composi t ion. Hydros ta t i c weighing i s used to determine an i n d i v i d u a l ' s body dens i ty from which a percentage of body-f a t can then be c a l c u l a t e d . This procedure i s not d i f f i c u l t a l though i t requires the subject to be submerged under water f o r 4 or 5 seconds. I t i s expected that your son w i l l complete these tes ts without compl ica t ions . Because o f the very uncommon, unpredic t -able response of some i n d i v i d u a l s to e x e r c i s e , unforseen d i f f i c u l t -i es may a r i s e which would necess i ta te treatment. Complications have been few during exerc i se t es t s and these u s u a l l y c l e a r q u i c k l y with l i t t l e or no treatment. Your son i s asked to report any unusual symptoms dur ing the t e s t i n g procedures . Your son w i l l be able to stop e x e r c i s i n g at any time because o f f ee l ings of fa t igue or d i scomfort . Every e f f o r t w i l l be made to conduct the tes ts i n such a way as to minimize discomfort and r i s k . P r i o r to the ac tua l t e s t i n g sess ions your son w i l l be allowed a 5-10 minute warm-up p e r i o d . At any time through the course o f the study you or your son may f e e l f ree to ask quest ions about the nature or des ign of the study. In s ign ing th i s consent form you s ta te that you have read and understand the d e s c r i p t i o n o f t e s t s , and the p o s s i b l e compl icat ions i n v o l v e d . Your son enters the t e s t i n g procedures w i l l i n g l y , but may withdraw or refuse to p a r t i c i p a t e at any t ime. F i n a l l y , a l l o f the in format ion and data that i s c o l l e c t e d about your son w i l l be' kept i n the s t r i c t e s t conf idence , i n a locked f i l i n g cabinet . CONSENT: I have read the above comments and understand the explanat ions which are g iven . I approve o f my son p a r t i c i p a t i n g i n the-e t e s t i n g procedures . SUBJECT'S NAME: PARENTAL CONSENT GIVEN BY: DATE WITNESS