at THE EFFECT OF TWO METHODS OF INTERVAL TRAINING ON THE PHYSICAL PERFORMANCE AND OXYGEN RECOVERY CURVES OF ROWERS BY PETER KLAVORA Di p l . Econ., University of Ljubljana, 1963 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION i n the School of Physical Education and Recreation We accept t h i s thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA August, 19 72 In p resent ing..th is. thes is , in, pa r t i a l f u l f i lmen t o f the requirements f o r an advanced degree at the Un iver s i t y of B r i t i s h Columbia, I agree that the L ibrary sha l l make i t f r ee l y ava i l ab le for reference and study. I fu r ther agree that permission for extens ive copying of th i s thes i s fo r s cho la r l y purposes may be granted by the Head of my Department or by his representat ives . It is understood that copying or pub l i c a t i on of th is thes is f o r f i nanc i a l gain sha l l not be allowed without my wr i t ten permiss ion. Department of s c h o o l of P h y s i c a l E d u c a t i o n and Recreation The Un ivers i ty o f B r i t i s h Columbia Vancouver 8, Canada Date August 24, .1972 1 ABSTRACT • The effectiveness of two t r a i n i n g methods was examined. Two equally fa s t v a r s i t y 'four-oar' crews were assigend to two i n t e r v a l . t r a i n i n g programs i n the late stages of preparation for the competitive season. The three experimental testings measured t o t a l work performance completed i n s i x minutes on the rowing ergometer and t o t a l oxygen consumption i n 15 minutes of recovery. Improvement i n the slope and the rate of the fa s t phase and the slow phase of the oxygen debt curve provided additional c r i t e r i a i n judging the superiority of one method over the other. A l l rowers were expected to improve t h e i r rowing performance as well as t h e i r t o t a l oxygen debt a f t e r an eight week t r a i n i n g program. The rowers following t r a i n i n g program A were expected to show greater improvement i n . a l l t esting parameters than the rowers following t r a i n i n g program B. A t h e o r e t i c a l exponential function of the form — K i t —Tfot A = A^e -1- + A^e z was f i t t e d to the oxygen data i n recovery for a l l subjects i n a l l three testings. Parameters of the oxygen debt curve, A^, K^, A2, K2, were calculated and treated s t a t i s t i c a l l y . Analysis of variance was used i n order to study the e f f e c t of t r a i n i n g and the e f f e c t of the two t r a i n i n g methods on the experimental subjects. The results showed a s a t i s f a c t o r y f i t of the t h e o r e t i c a l function to the experimental data of oxygen consumption. The oxygen debt curves aft e r an exhaustive rowing exercise were si m i l a r i n shape to curves obtained i n moderate exercise by other experimenters. The results showed that there was a s i g n i f i c a n t s t a t i s t i c a l improvement over t r i a l s i n rowing performance, t o t a l oxygen debt, and A-^ parameter of oxygen debt curve for the rowers as a t o t a l group. The increase i n A-j. was presumably due to the a b i l i t y of the subjects to maintain a higher oxygen consumption i n the terminal stage of work in the l a s t t e s t i n g . There was no s i g n i f i c a n t difference between the two t r a i n i n g programs i n any of the t e s t parameters. The results obtained, however, were i n the d i r e c t i o n expected by the stated hypotheses. The rowers who followed t r a i n i n g program A reported s l i g h t l y higher values for subjective feelings of tiredness immediately a f t e r i n t e r v a l rowing session and on the following day. This was as expected. TABLE OF CONTENTS CHAPTER PAGE I INTRODUCTION TO THE PROBLEM 1 -The Purpose 3 -The Problem 4 - C r i t e r i a to be Used i n Judging the Superiority of Method A 5 -General Hypothesis of the Study 5 - J u s t i f i c a t i o n of the Problem 6 -Delimitations 8 -Limitations 8 -Assumptions 8 -Definitions 9 II REVIEW OF RELATED- LITERATURE 11 - S c i e n t i f i c and Empirical Aspects of Modern Training Methods 11 - S c i e n t i f i c Research of Interval Training 12 -Empirical Research of Interval Training i n Track and F i e l d 17 -Empirical Research of Interval Training i n Rowing 27 -Oxygen, Consumption Pattern i n Man Following an Exercise 30 -The Nature of Recovery Oxygen Curves and Individual Differences 36 v i CHAPTER PAGE II -Training E f f e c t of Oxygen.Consumption i n Recovery 40 III METHODS AND PROCEDURES 45 -Introduction 45 -Subjects 45 -The Design of the Training Programs 46 -Design of the Testing Program 48 -Apparatus 50 -Testing Parameters 53 - S t a t i s t i c a l Analysis 54 IV RESULTS AND DISCUSSION 5 8 -Results 5 8 -Discussion 69 -Nature of Rowing Test . 69 -Oxygen Intake i n Recovery (Debt) Curves 71 -Rowing Performance, Total Oxygen and the Parameters of the Oxygen Debt Curves: A^, K 1, , K,, 75 -Discussion oh Changes i n A^ + A2 Due . to Training i n Exhausting Exercise 79 -Interval Training Methods A and B 81 v i i CHAPTER PAGE V SUMMARY AND CONCLUSIONS 86 Literature Cited 89 Appendices. A. Instructions for Testing Procedure 9 8 B. Fatigue Scale Questionnaire 99 v i i i LIST OF TABLES TABLE PAGE 1 Data on One Subject Performing 64,800 kpm on a Bicycle Ergometer within 1 hour with . Different Procedures 13 2 Results of Elfimov's Experiment 20 3 Rowing Performance (R.P.) Score i n Ergs/6 min and Total Oxygen (T.O.) Consumption i n L/15 min 58 4 Analysis of Variance f o r Rowing Performance Score 59 5 Analysis of Variance for Total Oxygen Debt 60 6 • Predicted Oxygen Debt Parameters A^ and i n L/min, and and Y.^ i n min~l 65 7 Analysis of Variance for A,, K, , A», and K 2 67 8 Median Fatigue Scores 68 i x LIST OF FIGURES FIGURE PAGE Comparison of Measured Oxygen Debt to Calculate Equivalents of Excess Lactate (Oxygen Necessary for Conversion to Pyruvate) 35 Exercise and Recovery Curves; Experimental Points Represent Average of 12 Subjects Measured at Lightest Bicycle Work Load by the C l o s e d - c i r c u i t Method. Recovery Portion of the Curve was Calculated from Formula 2 (42:430) 37 Testing on the Leichart Rowing Ergometer; Front and Side Positions 52 Predicted and Observed (broken line) Oxygen Debt Curves f o r Three Ss - i n Testing 1. Each Curve has a Different Base Line 62 5 Above: Predicted Average Oxygen Debt Curves for Two Methods i n Testing 1. Below: Predicted Average Oxygen Debt Curves for Two Methods i n Testing 3 as Compared to Predicted and Observed (broken line) Total Average' ( a l l Ss) Oxygen Debt Curves i n Testing 1 63 6 Average Oxygen Debt Curves for Method A and Method B i n Testing 2 64 X ACKNOWLEDGEMENT I wish to express my.appreciation to Dr. Brown for the help and guidance he has given me, and for being the Adviser of my committee. I also wish to thank Dr. Butt, Dr. Coutts, and Dr. Schutz, the committe members and Mr. Halm for his help with computer programming. Special acknowledgement"is due to Mr. Erickson, rowing coach at the University of Washington,, for l e t t i n g me use his rowing ergometer. CHAPTER I INTRODUCTION TO THE PROBLEM Rowing i s not a sport which lends i t s e l f e a s i l y to study. I t i s therefore not surprising to f i n d a paucity of information concerning t h i s a c t i v i t y i n .the l i t e r a t u r e . Only i n recent years have serious attempts been made to remedy thi s s i t u a t i o n . One aspect of rowing science which has received attention i n the expanding l i t e r a t u r e i s that which deals with aerobic and anaerobic metabolism during racing. The question of r e l a t i v e contributions of aerobic and anaerobic metabolism to the work of rowing has not been answered s a t i s f a c t o r i l y yet. Adam (1), Robertson (80), and Samsonov (85,86) regard aerobiosis and anaerobiosis as equal partners i n the provision of energy. Hagerman (35), on the contrary, emphasizes the aerobic metabolism as the source of most of the energy provided for rowing i n competition. The results of his research (32, 33, 34, 35) indicate a marked aerobic response of the rower during each of the s i x minutes rowing e f f o r t . The average oxygen debt seemed rather low as compared to the aerobic metabolism requirements, thus suggesting that aerobic metabolism i s the source of most of the energy provided.for rowing exercise. Hagerman's findings are substantiated by extensive research ca r r i e d out with oarsmen i n the German Democratic Republic (20). 1 2 Ideally, then, according to Hagerman, an oarsman's conditioning program should include high quality prolonged' work of 70 percent to 80 percent maximal capacity and t h i s work should take up at least 80 percent of his t o t a l t r a i n i n g time. Interval t r a i n i n g and anaerobic speed play are valuable additions to the program which has as part of i t s objectives s p e c i f i c conditioning for sprints during the race and a f i n i s h i n g kick at the end. The major consideration i n the preparation of a t r a i n i n g program should thus be task s p e c i f i c i t y . Endurance and speed can be developed compatibly by concentrating on ;.. separate s p e c i f i c tasks that e l i c i t maximal responses from either aerobic or anaerobic pathways. The greatest aerobic response comes from t r a i n i n g s t i m u l i involving long distance and f a r t l e k work, while anaerobic metabolism i s f a c i l i t a t e d by i n t e r v a l or anaerobic f a r t l e k t r a i n i n g . Hagerman (33) suggests concentration of i n t e r v a l work only as major regattas, near. This intense work seems to improve the athlete's a b i l i t y to r e s i s t acute fatigue and improve anaerobic capacity, so important during the spr i n t and f i n a l kick of the race. Interval t r a i n i n g has two d i s t i n c t advantages over the longer work. I t permits the crew to sample intermittent bouts of work at race pace which are necessary i f the crew i s to be properly prepared neuromuscularly and the physical d i s -comfort experienced as a r e s u l t of accumulative e f f o r t s conditions the crew for s i m i l a r experiences which w i l l most l i k e l y occur during the s p r i n t . No exact s c i e n t i f i c means has yet. proven f u l l y successful i n assessing the correct recovery period for athletes i n i n t e r v a l t r a i n i n g . The most recognized authorities i n track and f i e l d , where most of the research has been undertaken and ultimately copied by rowing coaches, are of the opinion that the i n t e n s i t y of the demand i n each bout of exercise should be faster than the target racing speed. : Experience of leading rowing coaches has shown that faster than the target racing speed i n i n t e r v a l t r a i n i n g over 500 to 600 metres can be achieved only i f recovery periods become progressively longer i n a t r a i n i n g session or i f number of repetitions remains r e l a t i v e l y small (up to s i x ) . In so doing, however, the main purpose of. i n t e r v a l t r a i n i n g , namely, to e l i c i t the maximal response of the anaerobic pathway, i s reduced s i g n i f i c a n t l y . The present study was undertaken i n order to investigate i f there are s t i l l better t r a i n i n g procedures which can e l i c i t higher responses from, anaerobic mechanisms than the conventional t r a i n i n g methods previously t r i e d . The Purpose' The purpose of t h i s study i s to determine whether or not one t r a i n i n g procedure used i n the preparation of v a r s i t y rowers for competitive rowing i s superior to another;- Both are s i m i l a r i n respect to the t o t a l distance rowed, but are q u a l i t a t i v e l y d i f f e r e n t i n the adaptive response required of the anaerobic mechanisms during hard i n t e r v a l work. The Problem The problem of the study i s to examine i f one i n t e r v a l t r a i n i n g method (A) i s superior to another i n t e r v a l t r a i n i n g method (B) using several c r i t e r i a of performance. Both methods require equal amounts of work and allow equal amounts of re s t time per t r a i n i n g session. However, the patterns of power output during i n t e r v a l t r a i n i n g sessions are l i k e l y to be i n d i s t i n c t contrast to each other. Method (A) i s an i n t e r v a l t r a i n i n g program where times between workbouts decrease throughout the i n t e r v a l t r a i n -ing session. I t i s designed to condition the crew for si m i l a r exhausting experiences which w i l l most l i k e l y occur during the spr i n t and f i n a l kick of the race by the physical discomfort experienced as a r e s u l t of accumulative e f f o r t s and progressively increased amounts of oxygen debt c a r r i e d over from workbout to workbout. Method (B) i s an i n t e r v a l t r a i n i n g program i n which the times between workbouts increase, i . e . there are progressively longer recovery periods throughout the d a i l y t r a i n i n g period. I t i s designed to eq u i l i b r a t e the amount of oxygen debt car r i e d over from one workbout to another. 5 C r i t e r i a to be Used i n Judging the Superiority of Method (A) 1. Improvement i n t o t a l work performance completed i n s i x minutes on the rowing ergometer from week one to week four and week eight'. 2. Improvement i n oxygen debt from week one to week four and week eight as determined by the following c h a r a c t e r i s t i c s : a. improvement i n t o t a l oxygen debt coll e c t e d for 15 minutes after exercise during week one, week four and week eight; b. improvement i n the slope of the fast phase and slow phase of the oxygen debt curve; c. improvement i n the rate of oxygen consumption of the fast phase and slow phase of the oxygen debt curve. 3. Two subjective written responses of the rowers about the state of t h e i r tiredness a f t e r each i n t e r v a l t r a i n i n g session immediately afte r the workout and 24 hours l a t e r . 4. Interview response of the rowers to the t r a i n i n g methods i n week eight. General Hypothesis of the Study Both t r a i n i n g method (A) and t r a i n i n g method (B) w i l l improve performance i n competitive rowing. Training method (A) w i l l e l i c i t a greater adaptive response to the 6 pattern of fatigue development i n the l a s t stage of competitive performance and thus to anaerobic working conditions than method (B) . Method (A), therefore, i s superior to method (B) . The following are s p e c i f i c hypotheses of the study. Method (A) produces: Hypothesis 1: Greater improvement i n work performance. Hypothesis 2: Greater improvement i n t o t a l oxygen debt i n the c o l l e c t i o n period of the study. Hypothesis 3: Greater improvement in. the fast component of the oxygen debt curve. Hypothesis 4: Greater improvement i n the slow component of the oxygen debt curve. Hypothesis 5: Higher state of tiredness f e l t immediately a f t e r the i n t e r v a l t r a i n i n g session.. Hypothesis 6: Higher state of tiredness s t i l l f e l t 24 hours a f t e r the i n t e r v a l t r a i n i n g session. J u s t i f i c a t i o n of the.Problem It i s possible to work out a system of preparing top athletes for competition which,is not d e l i b e r a t e l y based on physiological concepts. The success of such a system would depend on the practices and experiences of the coach. The t r a i n i n g experience i s related to the achievements i n competition.. The r e s u l t s i n competitions become an i n d i c a t i o n of what was done and how i t was done in t r a i n i n g . Thus, the i n t u i t i v e or l o g i c a l approaches 7 to devising t r a i n i n g programs have been quite successful i n t r a i n i n g athletes since the feedback i n the form of performance and feelings of athletes provides an instantaneous and most useful kind of i n t e r a c t i o n between trie athlete and the coach and permits adjustment i n t r a i n i n g . The universal acceptance of a t r a d i t i o n a l approach to t r a i n i n g by t h i s method may, however, take a great deal of time and t h i s could be reduced greatly by a more s c i e n t i f i c approach.;; This study i s an example of such, a s c i e n t i f i c approach designed to gauge the effectiveness, of a new approach to anaerobic t r a i n i n g of competitive rowers i n the l a t e season of preparation for competition. Success i n rowing, where hard e f f o r t must be sustained over approximately six minutes,.requires the capacity to accommodate a large oxygen debt. Indeed t h i s i s probably the c r i t i c a l factor i n the l a s t stages of a- race between crews of equal s k i l l s . The method of t r a i n i n g to be evaluated i n t h i s study should e l i c i t a greater adaptive response to the pattern of fatigue development i n the l a s t stages of performance and thus to anaerobic working conditions than the conventional methods previously t r i e d . If the rowers can adjust to i t and also maintain morale,.there w i l l have been added, at least tentatively,, a very useful and valuable t r a i n i n g procedure i n the preparation of competitive rowers. 8 Delimitations The sample of t h i s study i s r e s t r i c t e d only to eight members of UBC's v a r s i t y eight which was broken down. / into two coxed fours for the purpose of t h i s experiment. The t r a i n i n g program involves s i x workouts per week over a period of eight weeks. Limitations S t a t i s t i c a l . 1. Only two coxed fours (eight subjects) are being studied. 2. There i s no random selection of the subjects i n that t h i s study involves a select group of athletes. Methodological. 1. The members of the two fours were a r b i t r a r i l y assigned to a particuILar four crew many, months p r i o r to the experiment on the basis of t h e i r rowing technique.. Assumptions 1. Any t r a i n i n g by the subjects during the experimental period w i l l be confined to p a r t i c i p a t i o n i n the experimental programs. 2. A l l subjects have-a desire to improve t h e i r rowing performance to i t s maximum possible l e v e l during the experimental period.-3. Rowing on. the rowing ergometer i s a true r e f l e c t i o n of the rowing in. a racing s h e l l . 4. Subjects w i l l row to complete exhaustion i n te s t i n g conditions. 9 Definitions Competitive rowing. This refers to c o l l e g i a t e races on the West Coast. Interval t r a i n i n g program. This i s a system of conditioning rowers i n which the rowers are'subjected to short repeated periods of work stress interspersed with periods of r e l i e f . I t involves f i v e variable factors, including: 1. the distance of the t r a i n i n g rows, 2. the number of repetitions,. 3. the speed of the t r a i n i n g rows, 4. the type of a c t i v i t y during the recovery period,, 5. the duration of recovery period a f t e r each workbout. The variable factors i n t h i s study are 2, 3, and 5. Recovery period. This marks the time period between workbouts. In t h i s experiment i t i s designed to vary from two to eight minutes i n each i n t e r v a l t r a i n i n g workout under both t r a i n i n g methods. Recovery period of si x to eight minutes' duration implies restoration or return to a r e l a t i v e l y normal re s t i n g state following exercise. Recovery period of two to four minutes implies only p a r t i a l restoration following exercise. Progressively shorter recovery periods. The duration of recovery period a f t e r each (or several) workbouts i s progressively shortened i n the same workout from eight to two minutes. Progressively longer, recovery periods. The duration of recovery period a f t e r each (or several) workbouts i n the 10 same workout i s progressively lengthened from two to eight minutes.. Workbout. This i s an a l l - o u t row over 560 metres. It involves approximately two minutes of rowing i n a coxed four event. Oxygen debt. In t h i s study, i t i s the amount of oxygen required i n the post-exercise recovery period of 15 minutes over the t o t a l quantity of oxygen which would have been consumed during same rest period. I t i s considered to be s u f f i c i e n t l y highly correlated with the oxygen debt capacity of the oarsmen so as to represent"that capacity for the purpose of t h i s study. Work performance. The t o t a l maximum number of rev-olutions of the fly-wheel a rower can achieve i n a s i x -minute a l l - o u t row on the rowing ergometeir. CHAPTER- II REVIEW OF RELATED LITERATURE S c i e n t i f i c and Empirical Aspects of Modern Training Methods A thorough review of l i t e r a t u r e pertaining to t h i s study revealed no experiment s i m i l a r to that described i n ' t h i s study, i . e . involving a longitudinal investigation of the e f f e c t s of d i f f e r e n t types of i n t e r v a l t r a i n i n g upon the performance of rowers on a rowing ergometer and on oxygen debt tolerance. There i s only a small amount of s c i e n t i f i c research dealing d i r e c t l y with i n t e r v a l t r a i n i n g methods. Most of the information which was uncovered dealt with i n t e r v a l t r a i n i n g i n track and f i e l d conducted i n f i e l d situations by famous coaches. Only a few studies dealt with i n t e r v a l t r a i n i n g as applied to rowing. The review of l i t e r a t u r e about i n t e r v a l t r a i n i n g has been organized into the following areas: S c i e n t i f i c research of i n t e r v a l t r a i n i n g ; Empirical research of i n t e r v a l t r a i n i n g i n track and f i e l d ; and Empirical research of i n t e r v a l t r a i n i n g i n rowing. The l i t e r a t u r e about oxygen consumption i n recovery period has been compiled under the following headings: 11 12 Oxygen consumption pattern i n man following an exercise; The nature of recovery oxygen curves and in d i v i d u a l differences; and Training e f f e c t of oxygen consumption i n recovery. S c i e n t i f i c Research of Interval Training On the basis of the res u l t s of his experiments with continuous and intermittent work on the b i c y c l e , Astrand (6.) concluded that the longer the work periods the more exhausting appeared the work, even though the res t periods were correspondingly increased. Working continuously without any res t periods, the subject could only t o l e r a t e a given high work load for nine minutes, at the end of which he was completely exhausted. The subject could not complete the required amount of work of 64,800 kpm. I f , instead, he interrupted the work with frequent r e s t periods, the subject completed the required amount of work with moderate exertion. The r e s u l t s of his study are summarised i n Table 1. 13 Table 1 Data on One Subject Performing 64,800 kpm on a Bicycle Ergometer within 1 hour with Different Procedures Type of exercise °2 1/hr uptake 1/min Pulmon. v e n t i l . 1/min Heart rate, beats/ min Blood l a c t i c acid, mg/100 ml Continuous 2160 kpm/min* 4.60 124 190 150 Intermittent 2160 kpm/min Work Rest 1/2 min 1/2 min 154 2.90+ 63+ 150 20 1 1 152 2.93+ 65+ 167 45 2 2 160 4.40 95 178 95 3 3 16 3 4.60 107 188 120 *Could only be performed for 9 minutes. +Measured during 1/2 minute. Source: I. Astrand et a l . , 19 60. Christensen et a l . (11) and Hollman (49) reported s i m i l a r r e s u l t s . Hollman experimented on a treadmill ergo-meter where two or more attempts were made with d i f f e r e n t .1' loads for d i f f e r e n t durations, interspersed with varying periods of re s t . The 0^ uptake during the work and res t were registered. In s i m i l a r experiments on the b i c y c l e ergometer, the l a c t i c and pyruvic acid levels i n the venous blood were determined. Oxygen uptake i n work of average i n t e n s i t y , interrupted by short pauses was less than i n work of the same i n t e n s i t y , but performed continuously. Interval 14 work could be done with less accumulation of l a c t i c acid than work done continuously. Fox's et a l . (28) results agree with Hollman's investigations: The results showed that during i n t e r v a l running, blood l a c t i c acid accumulation and the l a c t i c acid oxygen debt were always much lower than when the same t o t a l amount of work was performed continuously. Consequently, by running i n i n t e r v a l s more work could be performed before l a c t i c acid accumulated to exhaustive l e v e l s . According to Hollman (50), the favorable function of i n t e r v a l t r a i n i n g i s the r e s u l t of the following ph y s i o l o g i c a l fac t s : During the loading phase the reserve c a p i l l a r i e s i n the musculature are opened,.the heart beat and heart stroke volume as well as the minute volume of v e n t i l a t i o n are increased. Then the a c t i v i t y i s stopped and the recovery phase sets i n : The main part of the recovery f a l l s within the 1 - 2 minutes of recovery during which, on the average, 60 - 80 percent of the recovery takes place . . . depending on . . . i n t e n s i t y . . . duration of work. When at l e a s t three quarters of the recovery has been completed and the new loading i s resumed, . . . the heart, c i r c u l a t i o n and r e s p i r a t i o n are then s t i l l adapted to the work, i . e . the heart beat i s s t i l l high, the stroke volume s t i l l increased and the reserve c a p i l l a r i e s are s t i l l open. Consequently, the new work (second load) can be resumed aerobically almost immediately. What i s more, the l a c t i c acid l e v e l in the a r t e r i a l blood remains r e l a t i v e l y low. 15 Low l a c t i c acid l e v e l i n the a r t e r i a l blood corresponds with l i t t l e fatigue (28) which would permit an athlete a larger dosage of work. For the required t r a i n i n g e f f e c t , however, the t o t a l amount of work done plays an important r o l e ( 1 , 3, 7, 2 7 ) . Equally important i s continuous a l t e r -nating of loading and unloading which stimulates the organism i n higher adaptations, thereby . forcing the organism to optimal development ( 7 , 4 9 ) . Hollman's results and explanations are substantiated by investigations by a group of s c i e n t i s t s from Freiburg (Reindell et a l . [79] , Gerschler [ 30J , Roskam et a l . [ 81] ) i n connection with the heart and i n t e r v a l t r a i n i n g . They established that i n the course of t r a i n i n g according to the p r i n c i p l e s of i n t e r v a l t r a i n i n g l a s t i n g not even a f u l l two months, the heart volume was increased by more than 100 ccm., a r e s u l t which u n t i l then normally took several months and even years to achieve. Reindell explains t h i s as follows: The vigorously pumping heart i s outwitted by the.short'pause,. and induced to transport the f u l l volume of blood through the s t i l l open . peripheral a r t e r i e s , thus retaining the stimulus on the heart while the s k e l e t a l musculature i s recovering. In t h i s way, too, the cardiac muscle receives more t r a i n i n g than i n the continuous form of endurance t r a i n i n g . (79) The numerous s t i m u l i to which the heart i s subjected i n a b r i e f period of time results i n a strong development of the heart i n a much shorter time than i s possible i n any other method of t r a i n i n g . 16 Freiburg's group of s c i e n t i s t s (30,. 78, 79, 81) advanced the thesis that every demand which should evoke an optimum development of endurance has to be accomplished according to the rule of pulse frequency. This law of pulse frequency states that the demand on the organism must be high enough for the pulse to r i s e to 180 beats per minute. The rest must be long enough for the pulse rate to drop to 120 beats per minute. Gerschler (30) further indicated that t h i s rate lasted i n most cases for only f i v e seconds after exercise, sometimes ten seconds, but never f i f t e e n seconds, and suggested that t h i s should be a p o s i t i v e consideration when planning the i n t e r v a l t r a i n i n g i n t e n s i t y , adding that neither the distance covered, be i t 100, 200, 400 metres etc., nor the number of r e p e t i t i o n runs modified the frequency. E a r l i e r , Muller (70) and Lehmann (61) had already discovered the importance of pauses or i n t e r v a l s i n "Arbeitsphysiologie". In labor investigations i n which the . production and pulse- rate were taken as c r i t e r i a , an optimum working time and the length of rest period had been established. Their investigation revealed that short pauses are highly superior since the process of recovery takes place i n the shape of an exponential curve so that the greatest part of the recovery takes place during the f i r s t two minutes after the completion of the work. 17 In summary, then, the athlete i s able to maintain the highest work load for-longer period of time only i f a c t i v i t y i n t e r v a l s are interrupted with frequent r e s t periods. The numerous"stimuli to which the athlete i s subjected i n a b r i e f period of time r e s u l t i n a strong development of his muscle strength i n a much shorter time than i s possible i n any other method of t r a i n i n g . On the other hand, a t r a i n i n g of the oxygen-transporting system w i l l be more e f f e c t i v e i f the exercise periods are'prolonged to at l e a s t two to three minutes, followed by r e s t periods. This type of work'would also adapt the tissues to high lactate concentrations, providing the exercise i s severe. The controlled recovery phase i s the key to strengthening the heart and so improving endurance markedly. Empirical .Research of Interval Training in Track and F i e l d Zatopek (98), running as much as 60 times 4 0 0 metres with a 2 0 0 metres recovery jog at times i n his t r a i n i n g sessions, astonished the world with the s i m p l i c i t y and i n t e n s i t y of hi s workouts. In due course, i t became customary to speak of the Zatopek method which eventually became what i s today known as Interval Training. However, i n t e r v a l t r a i n i n g becomes much more complex i f a l l possible t r a i n i n g s t i m u l i of this method are taken i n t o consideration. According to Nett (73), there are f i v e possible t r a i n i n g s t i m u l i : 18 1. Distance of runs. 2. Intensity or speed of runs. 3. Number of st i m u l i - number of dashes 4. Duration of recovery s t i m u l i . 5. Nature of recovery phase. Obviously, hundreds of these combinations are possible and, as Doherty (17) put i t , I t w i l l be quickly seen that each of these elements can be stressed or lessened, fixed or varied i n accordance with the a b i l i t y of each runner or with the p a r t i c u l a r view of the.coach. However, empirical research has concentrated mostly on three main factors to be considered when compiling an i n t e r v a l t r a i n i n g schedule: 1. The i n t e n s i t y of the demand. 2. The duration of rest phase. 3. The number of r e p e t i t i o n s . The i n t e n s i t y of the demand. Down (19) interprets i n t e r v a l t r a i n i n g i n t h i s manner: With better speed the objective i s on qua l i t y of performance and not on quantity. I t i s not what one does, but how one does i t , . . Estab l i s h present speed and make his objective an improvement on "that . . . . Lucas (6.2). quotes P e r c i v a l as saying: The repetitions of the distances shorter than the event for which the athlete i s t r a i n i n g at. a pace a l i t t l e faster than or the same as the race pace objective, i s the fastest and most e f f e c t i v e way to develop endurance. Doherty's (18) interpretation of i n t e r v a l t r a i n i n g places the emphasis on the goal a runner hopes to obtain at the end of 19 the season. He bases his variables i n the following manner: 1. One-half the racing time or pace - endurance t r a i n i n g . The fixed variables are distance, pace, and res t period with the number of repetitions being varied. 2. One-fourth the racing time or speed - endurance t r a i n i n g . The fixed variables are distance, r e s t and the number of re p e t i t i o n s , with pace being changed. I g l p i (69) introduced sets or series of short, intense repetitions of running. The running of sets of repetitions over short distances at high speeds enabled I g l o i ' s athletes to achieve excellent competitive results over a wide variety of distances. According to Ozolih (77), the running pace i n i n t e r v a l t r a i n i n g should be faster than race pace, but not the maximum, i f spe c i a l endurance i s to be developed."'" Ozolih (77) also reports the f a i l u r e of Pugachevski to improve s i g -n i f i c a n t l y the times of his athletes when trained at a l l -out e f f o r t . Laboratory and f i e l d experiments with 800 metre runners were conducted by Elfimov (21). His results i n Table 2 show that the greatest increases i n working capacity were attained by. the groups which trained at a faster than race pace, but not at a l l - o u t e f f o r t . The exercise used was running i n place. 'Special endurance i s the endurance necessary for the p a r t i c u l a r event. 20 Table 2 Results of Elfimov's Experiment Test group Training Duration of run to l i m i t % pace at pace of 2 30 steps/min increase steps/ P r i o r to Post' i n work min t r a i n i n g t r a i n i n g capacity 1 2 3 230 300 260 52.3 sec 52.0 sec 54.3 sec 72.3 sec 98.6 sec 106.3 sec 38.3 89 .6 95. 8 Stampfl (88) would increase the speed of running only a f t e r s u f f i c i e n t mileage was covered at a slower than competitive pace. Jewkes (56) expressed si m i l a r b e l i e f : When the athlete has got used to the volume of work, the number of fast i n t e r v a l s should be gradually reduced while the speed i s increased. Zatopek (98), on the contrary, expressed the opinion that better results were obtained by more volume and slower i n t e r v a l s . Roskamm, Reindell and Keul (8.1) , too, promote the improvement of muscle stamina or endurance through very numerous repetitions of contractions with sub-maximum e f f o r t . Low speed i s d i r e c t prerequisite of effectiveness of the i n t e r v a l t r a i n i n g method on heart stimulation i n the recovery as stated by Freiburg's law of pulse frequency (30, 79, 81). On the basis of the res u l t s of hi s f i e l d work, Nett {12, 73, 74), who has been a great follower of 21 Freiburg school of tr a i n i n g , came to the conclusion that slow pace and short distances up to 200 metres, as required by Gerschler and Reindell, are not s u f f i c i e n t i n t r a i n i n g athletes for competitions successfully. In addition to " c l a s s i c a l " i n t e r v a l t r a i n i n g , he introduces tempo running which requires faster than racing pace and extends up to 1,000 metres and, occasionally, more. He admits that tempo running which i s e s s e n t i a l l y i n t e r v a l type of t r a i n i n g , . . . does not permit - as we have seen - any s p e c i f i c e f f e c t upon the heart because of the absence of increase i n the beat-volume during recovery. Hence i t s e f f e c t on the metabolism adaptation of the heart remains li m i t e d . (72) However, a faster tempo i s necessary for muscle adaptation. The high speed i s the r e a l stimulus on the muscular system and i t s metabolism (19, 74). Nocker (76) believes that the muscles' increased capacity for prolonged e f f o r t i s cl o s e l y related with the potassium content i n the muscles. The more exhaustive i s the work the lower the potassium content. After absolutely exhausting work, the potassium content i s considerably lower i n the trained muscle than i n the un-trained muscle. I t is., therefore, e s s e n t i a l . . . that the sti m u l i (speeds) are strong enough . . . t h a t lead to the emptying of. the potassium battery and . constitute a s u f f i c i e n t stimulus so that during the resting-phase a re-charge i s made possible which exceeds the o r i g i n a l potential . . . on the basis of th i s . . . the muscular system generally requires the time to be longer and the stimuli,to be i n greater doses (higher speeds) than i s necessary for the process of conditioning the c i r c u l a t i o n system. I recommend days with faster runs. (76) Astrand (7) f u l l y agrees with Nocker: .... A t r a i n i n g that i s prolonged to at least two minutes . . . would adapt the tissue to high lactate concentrations-'- providing the exercise i s severe. The next step.in the development of modern t r a i n i n g methods i s the appearance of the New Zealand runners trained by Lydiard. Lydiard (63) ascribed his success to marathon 2 t r a i n i n g . However, the closer Lydiard came to the racing season, the shorter were the demands placed on his runners and the faster were the speeds required of them. The duration.of the r e s t phase. By keeping the re s t heart stroke volume up at a rate of 120 beats per minute, according to Freiburg school (30, 79, 81), the heart i s induced to transport a large volume of blood through the a r t e r i a l system, whose c a p i l l a r y network remains continuously d i l a t e d . This, as Hollman (49, 50) also confirmed, maintains the stimulus on the heart while the s k e l e t a l musculature was recovering, so enabling the next e f f o r t to be resumed aerobically with the l e v e l of the l a c t i c acid r e l a t i v e l y low.1 Thus the favorable function of i n t e r v a l t r a i n i n g i s while the athlete i s resting. However, the r e s t phase should not exceed 90 seconds. If i n the course of the d a i l y workout the pulse at the end of the pause, as compared with 120 at Which Astrand relates to oxygen debt requirement. Marathon t r a i n i n g would involve a steady state running at' a reduced e f f o r t for long periods of time. 23 the beginning of the workout i s s u b s t a n t i a l l y increased, the workout must be terminated. Nett (73) deduced the following p r a c t i c a l basic p r i n c i p l e s : 1. Duration of the pause should be 4 5 - 9 0 seconds. 2. Duration of the i n d i v i d u a l exertion (run) one minute at the most. 3. Intensity of the i n d i v i d u a l exertion should be such as to produce a pulse frequency of 120 to 140 at the end of the pause. However, i n tempo running, ; Nett (74) advocates some-what longer r e s t pauses: The speed and distance chosen i n tempo running decides (by the degree of excess acidization) . . . the duration of the recovery pauses. S i m i l a r l y , Nocker (76) advocated computing one-third of the difference between the pulse at r e s t and the pulse during exertionj and subtracting the quotient from the maximum pulse rate during exercise. Nocker claimed that t h i s was the figure at which, a f t e r a sudden drop, the heart rate tends to s t a b i l i z e and was the point at which the next e f f o r t should be begun. According to Diem (15), the recovery must l a s t only u n t i l the breathing and the heart are calm again and a f e e l i n g of freshness i s f e l t . Immediately aft e r that, the work (activity.) must be resumed so that the athlete does not get unaccustomed to strenuous work, i . e . before he has completely recovered. 24 Down (19) concluded that whichever authority one was prepared to accept, i t was apparent that the c r i t i c a l range was from 120 - 180 heart beats per minute. To claim a more precise threshold was surely presumptuous. Zatopek (9,8) used a standard 200 metre recovery jog which lasted up to one minute.. A few years l a t e r , Kuts (101) who broke Zatopek's records, repeated Zatopek's workouts. However,.the i n t e n s i t y of his runs was somewhat greater and the duration of his recovery was shorter. Laboratory and track experiments with 800 metre runners were conducted by Elfimov and Ozolin (22, 77). When the test runners were doing 400 metre r e p e t i t i o n s , i t was noted that the second r e p e t i t i o n was usually slower than the f i r s t . They found that i n order to run i d e n t i c a l times for the f i r s t two re p e t i t i o n s , 15 to 20 minute r e s t was necessary. With three minutes' re s t the second 400 metres were about seven seconds slower than the f i r s t . This gap decreased to about zero second for 15 to. 20 minute rest, but taking more than 20 minutes also produced a slower and slower second 400 metre run. Additional tests by Elfimov (21) with two groups of 800 metre runners, each of whom did 20 tr a i n i n g sessions of repetitious running, showed that the group taking 20 minutes rest between repetitions improved t h e i r 800 metre time by 4.5 to 5.1 seconds, whereas a second group taking seven minutes re s t improved by only 2.1 to 2.5 seconds. 25 The.number of repetitions.. As a general rule instructs Nett (75) the t o t a l volume for each workout may be two or three times actual racing distance, exclusive of warmup and recovery or slow running. However, mature runners of international c a l i b r e recognize no such boundaries and frequently put i n far more'total running volume each work-out over a prolonged t r a i n i n g period (98, 101). Stampfl (88) also recommended numerous repetitions at a slower than racing speed which would far exceede the actual racing distance. Mole (68) i n his study of the influence of number of repetitions i n i n t e r v a l t r a i n i n g on the aerobic metabolism and endurance performance of four young men indicated that aerobic metabolism, running e f f i c i e n c y , endurance performance, and oxygen requirement for the a l l - o u t treadmill run tended to improve as the t o t a l workout increased. On the contrary, Leclerq (6.0) stated that every r e p e t i t i o n of e f f o r t a f t e r the s i x t h i s questionable as regards the e f f i c i e n c y of t r a i n i n g adaptation. Ozolih (77) believes that the t o t a l sum of the f a s t stratches should be more than one and one-half to two times as much as the athlete's racing distance. I t can be concluded that the subject i s both vast and controversial as far as the i n t e n s i t y , duration of r e s t and the number of repetitions are concerned. Some coaches and s c i e n t i s t s (98, 68, 75, 88, 101) believe that the best 26 r e s u l t s accrue from a great number of comparatively slow i n t e r v a l s . Mother (60, 77) prefers a smaller number of interva l s performed at a speed very much faster than racing pace. S t i l l another (69) believes i n a l l - o u t e f f o r t s only. The most'recognized authorities are of the opinion that the i n t e n s i t y of the demand should eventually be faster than the target racing speed. No exact s c i e n t i f i c means has yet proven f u l l y successful i n computing the correct recovery period for each i n d i v i d u a l i n the various types of i n t e r v a l t r a i n i n g . Whatever the length or a c t i v i t y during.the recovery period, i t i s evident that coaches work on the concept of p a r t i a l recovery. The recovery period is short enough so that athlete never recovers completely. However, as the athlete becomes more f i t , the time needed for adequate recovery decreases. There i s no s u f f i c i e n t uniform evidence to y i e l d any s t r i c t r u l e for assessing the number of r e p e t i t i o n runs. The only conclusion that could be made i s that the t o t a l length of f a s t runs i n a workout should exceed the length of the racing distance. Hollman (49) , however, made an important observation. This was that the necessary prerequisite for the success i n his research was that the duration of work, the i n t e n s i t y of work and the length of the re s t pause were i n r e l a t i o n to one another according to what was optimal for the subject. He also proved that every subject had an i n d i v i d u a l optimum. Thus, i n d i v i d u a l differences must always be taken into account i n compiling an i n t e r v a l t r a i n i n g program (99), What i s even more important, according to many leading coaches and former f i r s t class runners, i s the optimum mixture of d i f f e r e n t t r a i n i n g methods. The trend"in modern tra i n i n g today seems to be the complex t r a i n i n g (17, 18, 63, 72, 88) . Empirical Research in - I n t e r v a l Training in Rowing In t r y i n g to apply the p r i n c i p l e of i n t e r v a l t r a i n i n g to rowing i n 1950, Adam (1) was confronted with unlimited f l e x i b i l i t y of the method. Namely, the problem i s the one of organization of the variable factors of i n t e r v a l t r a i n i n g as to obtain the best e f f e c t with the least investment of time and e f f o r t i n t r a i n i n g . In t r y i n g to r e a l i z e t h i s aim, Adam came up with a form of t r a i n i n g which has become rather widespread i n rowing. This i s c a l l e d stroke play and consists of a regular change in the demands made on the oarsmen, i . e . , the demand between s p r i n t and racing strokes and r e s t periods. The c h a r a c t e r i s t i c form of t h i s exercise was 10-10-10. After the team had warmed up, there were ten sprinting, strokes or spurt strokes, ten racing strokes, and ten spurt strokes and t h i r t y l i g h t or rest strokes. According to Adam, the team should achieve . . . i t s maximum speed. The racing strokes should be executed as i f the team were going through a two thousand metre course i n the best possible time with an even tempo. The l i g h t strokes should remain 2 8 t e c h n i c a l l y precise, f u l l - l e n g t h strokes . . . the application of power should be reduced greatly. (1) This stroke play was further developed by the i n c l u s i o n of longer times during which demands were made' on the organism Thus the t r a i n i n g i n t e r v a l s 1 0 ^ 2 0 - 1 0 1 0 - 3 0 - 1 0 , or 1 0 0 powe strokes of 4 0 - 2 0 - 4 0 with the spurt strokes i n the middle are often used.. However, the number of r e s t strokes w i l l never be greater than 3 5 strokes. The t o t a l demand per unit of t r a i n i n g i n t h i s fashion i s four to s i x hundred strong strokes. In addition to stroke play, a second form of i n t e r v a l t r a i n i n g , tempo t r a i n i n g , based on an e n t i r e l y d i f f e r e n t consideration, was developed by Adam ( 2 , 4 ) . Since the two thousand metre stretch should be accomplished with as even pacing as possible, i t i s extremely important that each team knows which speed i t can maintain for two thousand metres . . . . There i s a simple rule that a speed which can be repeated over a distance of 5 0 0 to 6 0 0 metres, f i v e or six-times with l i t t l e v a r i a t i o n , i s s a t i s f a c t o r y . This speed can be maintained constantly, i n racing. . . . The team should go through these 5 0 0 or 6 0 0 metre distances twice;the speed they are to reach is. racing, then increase the number of repetitions to s i x or eight. Using these two i n t e r v a l t r a i n i n g methods, Adam came to the following i n t e r e s t i n g observation: If we used exclusively stroke play, we noticed a very rapid development'in the performance of the c i r c u l a t o r y system, but no increase i n the l o c a l muscular endurance . . . . I f we added tempo tr a i n i n g , t h i s condition was eliminated. ( 2 ) Adam's stroke play t r a i n i n g corresponded very cl o s e l y to 29 Freiburg's pulse frequency law which places a very high e f f e c t on the c i r c u l a t o r y system. However, d i f f e r e n t kinds of demands - tempo t r a i n i n g - must be made on the organism i n order to improve l o c a l muscular endurance. This notion would agree with Nett (72) and other coaches who advocated longer stretches at racing speed. Robertson (80) "'"of New Zealand incorporated Lydiard's t r a i n i n g methods and believes that long distance rowing creates a firm, basis on which, with s p e c i a l i n t e r v a l t r a i n i n g over short distances, he achieves an a b i l i t y to work at high speeds for short periods' of time. S i m i l a r l y , Harre (36) indicates that the human body possesses capacities which are best developed under demands of long duration. Consequently, East German rowing': team covers 20 to 30 kilometres two or three times a day at a steady state and only some distance i s rowed at a racing speed. Harre (36) extends the number of variables of i n t e r v a l t r a i n i n g to seven as adopted to the needs i n rowing. 1. The duration of demands on the organism. 2. The i n t e n s i t y of the demands on the organism. 3. The number of strokes per minute. 4. The length of the pause between these demands. New Zealand National Coach for Olympic Rowing Team. 30 5. Intensity of the demands during the pause. 6. The number of r e p e t i t i o n s . 7. The t o t a l amount of i n t e r v a l t r a i n i n g i n one's t o t a l t r a i n i n g program. . He believes that i n t e r v a l t r a i n i n g i s the most'ver-s a t i l e method of t r a i n i n g which could be adopted by young and old, women and men a l i k e , and could be varied according to the future goals i n performance, technical a b i l i t i e s of the oarsmen and t h e i r s p e c i f i c psychological need and physical a b i l i t i e s of the p a r t i c u l a r crew. A l l three main t r a i n i n g methods: interval,.long distance steady state and complex, as established i n three leading rowing nations - West and East Germany and New Zealand -had bearings on the development of the Russian rowing program. In one-year cycles, the Russian school i s tr y i n g to incorpo-rate the main ingredients of a l l three methods i n preparation of t h e i r senior oarsmen for top competitions. In conclusion, i t could be said that i n an attempt to improve the performance of rowing crews, the authorities of the leading rowing nations accepted the p r i n c i p l e s of i n t e r v a l t r a i n i n g method as developed and advanced by the track athletes, ..particularly for middle and long distance runners. Oxygen Consumption Pattern i n Man Following an Exercise The f i r s t physiologists to study the changes i n 31 re s p i r a t i o n at the t r a n s i t i o n from work to rest dn man were Krogh and Lindhard (59) . They observed a marked change i n oxygen consumption rate af t e r the f i r s t few minutes. There was an i n i t i a l short period of rapid decline of the oxygen consumption, followed by a long period of slow recovery. I t remained for H i l l and associates (29, 47, 48) to term t h i s system of "paying back" oxygen that was apparently not available at the time needed, as "oxygen debt". After severe exercise . . . the i n i t i a l phase of recovery i s rapid, but a prolonged process supervenes which may take as much as 80 minutes to reach completion . . . . There are c l e a r l y two factors at work . . . the i n i t i a l rapid f a l l i n the oxygen intake on the cessation of exercise; the other for the prolonged remainder of recovery occurring after extended or severe exertion. (47) H i l l and colleagues were aware of the fas t component, but at that time thought i t to be a rapid phase of the l a c t i c debt: We"may conclude, therefore, that the f i r s t and rapid phase of recovery i s nothing more than oxidative removal of l a c t i c acid i n the muscles where i t was formed . . . . The second and prolonged phase, on the other hand, represents the oxidative removal of l a c t i c acid which has had time to escape by d i f f u s i o n from the muscles where i t was formed. (4.7) As for the nature of the payment of the oxygen debt, H i l l observes that . each process i s exponential i n character -one i s rapid; one, however, i s slow. Moderate exercise i s followed to a preponderant degree by recovery of the rapid type. (47) 32 Margaria, Edwards and'Dill (66) have reported fra c t i o n a t i o n of the post-work oxygen consumption in t o a rapid pay-off component that occurs as a r e s u l t of either l i g h t or heavy work, and a slow pay-off l a c t i c component, previously discovered by H i l l i n 1924, that i s hot o r d i n a r i l y observed unless heavy muscular work'has occurred. Among t h e i r findings was the observation that there was no increase of l a c t i c acid i n the blood accompanying the oxygen debts aft e r exercise u n t i l a subject worked at an i n t e n s i t y corresponding to two-thirds maximal oxygen consumption. As a r e s u l t of t h i s observation, the term "al a c t a c i d debt" was introduced. . . . because i t takes place without apparent extra l a c t i c acid formation . . . . This a l a c t a c i d mechanism of paying an oxygen debt i s much more convenient than the l a c t a c i d mechanism as fag as speed of payment i s concerned. This speed i s 30 times greater, taking only hal f a minute to pay 50% of the ala c t a c i d debt, while the payment i s p r a c t i c a l l y complete (98.5%) i n three minutes. (66) In another study, Margaria et al.-(67) repeated s i m i l a r observations as noted i n th e " e a r l i e r study (66). In addition/ there was no observable removal of l a c t i c acid at the beginning of recovery. To them, th i s indicated that there was a f r a c t i o n of the oxygen debt that was not related to the l a c t i c acid mechanism. Berg (10), Eskildsen (2.4) and Wells et a l . (95) confirmed these findings by Margaria. 33 Huckabee's work i n the late f i f t i e s i s i n d i r e c t c o n f l i c t with the above concept of an anaerobic threshold. In a series of studies ( 5 1 , 5 2 , 5 4 , 5 5 ) , Huckabee challenged the concepts of H i l l et a l . ( 4 7 , 4 8 ) and Margaria et a l . (6 .6 ) which related the oxygen debt of exercise to-changes i n blood lactate concentration. He developed a formula based on the lactate and pyruvate measurements. The c a l c u l a t i o n obtained related changes i n - l a c t a t e concentration to pyruvate metabolism and was termed "excess lactate" which, .according to Huckabee, should be d i r e c t l y related to tissue hypoxia and, therefore, oxygen debt ( 5 1 , 5 4 ) . Excess lactate = (L - L ) - ( P - P )x L / P ( 1 ) n o n o o o where L Q and P q are equal to the resting a r t e r i a l blood lactate and pyruvate concentration, respectively, and L n and P N are the same determinations during exercise. Furthermore, from the physiological significance Huckabee attached to excess lac t a t e , he concluded'that the metabolic a l t e r a t i o n s responsible for oxygen debt formation were e s s e n t i a l l y s i m i l a r at a l l grades of exercise ( 5 1 ) . If he calculated the quantity of oxygen necessary to convert the peak excess lactate back to pyruvate, he found close approximation to the measured oxygen debt. He found excess lactate at low levels of work with small oxygen debts, and the close approximation s t i l l held true ( 5 4 ) . L i t t l e or no t o t a l lactate had been found at these lev e l s by other investigations ( 6 6 , 6 7 ) . 34 On the basis of his research, Huckabee denied the existence of an a l a c t a c i d oxygen debt or an a l a c t a c i d portion of a large oxygen debt. He forwarded the thesis that v i r t u a l l y the entire debt could be accounted for at a l l levels of work with l a c t i c acid, s p e c i f i c a l l y excess l a c t a t e . Subsequent research by Knuttgen (58), Thomas et a l . (92), Astrand (7) and Wasserman et a l . (93, 94) and Naimark (71) reported that below a s p e c i f i c work load (anaerobic threshold) i n normal subjects, there i s a cardiorespiratory reserve and increase i n a r t e r i a l blood lactate does not occur u n t i l the energy requirement i s about four times basal.- This i s in•agreement with studies on blood lactate during exercise done by others (58, 66, 67, 95). Margaria et a l . (65) also reinvestigated the k i n e t i c s of oxygen debt formation and were unable to agree with Huckabee's int e r p r e t a t i o n of the significance of excess l a c t a t e . The experiment confirmed the delayed process of l a c t i c acid formation as found e a r l i e r by Margaria et a l . ' (66, 67) and others (58, 95), and . . . an exergonic anaerobic process, which i s not l a c t i c acid formation, must take place at' the beginning of exercise; t h i s i s the contraction of the a l a c t a c i d oxygen debt. (6.5) The combined research i s shown i n Figure 1. Measured debt ( L ) Figure 1 Comparison of Measured Oxygen Debt to Calculate Equivalents of Excess Lactate (Oxygen Necessary for Conversion to Pyruvate) As was stated, Huckabee (51,.54) could account i n i t s entirety for any oxygen equivalents of excess lactate.''" Therefore, the r e c t l i n e a r r e l a t i o n s h i p resulted. Later research (65, 71, 92, 93) f a i l e d to f i n d any r e l a t i o n s h i p with excess lactate u n t i l a debt of between one and-one-half and two l i t e r s was attained. . There was then a p a r a l l e l increase which always underestimated the t o t a l debt by about.the same amount throughout the entire range. These data would, therefore, support Margaria's concept of an al a c t a c i d portion of the debt. The concept of a l i n e a r increase i n excess lactate and oxygen debt as a function of t o t a l metabolic rate has also been attacked by Harris et a l . (39), Thomas et a l . (92) and Wasserman et a l . (93). The oxygen necessary to convert hypoxic lactate to pyruvate. 36 To confuse the subject more s t i l l , Harris et a l . (39, 40) and Thomas et a l . (91) obtained d i f f e r e n t r e s u l t s when they measured the rate of increase of excess lactate during exercise. In contrast to the l i n e a r increase of excess lactate with time described by Huckabee, they observed that excess lactate plateaus and even decreases. In a l a t e r study, Harris observed again excess lactate r i s e and f a l l , rather l i k e that for lactate i t s e l f and can become negative while exercise i s proceeding (38). In summary, then, research c l e a r l y shows the attempt of physiologists to l i n k the concentration of lactate i n the blood causatively with the oxygen uptake a f t e r exercise. The present s i t u a t i o n on the subject looks l i k e t h i s : 1. Margaria, Edwards and D i l l found an a l a c t a c i d portion of oxygen debt (66, 6 7) . 2. Huckabee denied i t s existence (51, 54). 3. More recent papers confirmed not only an a l a c t a c i d portion, but a lactate portion-as well (65, 93). 4.. Harris and Alpert believe the p o s s i b i l i t y that the concentration of lactate i n blood does not i n any way determine the magnitude of the recovery volume of oxygen (5, 39 , 40). The Nature of Recovery Oxygen Curves and Individual Differences H i l l et a l . (47) f i r s t pointed out that recovery curves for oxygen consumption are exponential, which has subsequently 37 been confirmed by other investigators (10, 65, 66, 67). According, to H i l l and Margaria et a l . (6.6), the oxygen recovery curve a f t e r strenuous exercise i s composed of two exponential curves, .an i n i t i a l rapid component l a s t i n g a few minutes, and a longer component of several hours' duration depending.upon the exercise i n t e n s i t y . After moderate exercise,.the recovery curve i s composed e n t i r e l y of the f i r s t component (alactacid) and can be represented by a t h e o r e t i c a l exponential expression * - K t A = A e o (2) Margaria et a l . (66) as well as others (42, 45) have found that the l a c t i c component of the t o t a l oxygen debt"of heavy exercise can be described by the same formula. Thus, the expression 1 becomes A- = - A 1 e" Kl t + - - A 2 e " K 2 t (3.) MXAXE Exercise and Recovery Curves; Experimental Points Represent' Average of 12 Subjects Measured at Lightest Bicycle Work Load by the Closed-Circuit Method.. Recovery Portion of the Curve was calculated from Formula 2 (42:430) 38 A Q i n formula 2 represents the rate of oxygen intake at the cessation of exercise and K represents the v e l o c i t y constant of the recovery curve. Veloc i t y constant K, according to Henry (42), i s not related to the rate of work at submaximal exercise and Berg (10) as well as others have indeed found i t to be independent. Thus, i f K remains constant at varying work loads for a p a r t i c u l a r i n d i v i d u a l , the s i z e of the debt w i l l be determined by the steady state oxygen income during.exercise which i s showing a l i n e a r r e l a t i o n with the rate of work up to the point where lim i t a t i o n s of oxygen supply to the working muscles came into action (42). Hence, the oxygen debt should also approximate a simple l i n e a r function of the rate of mild or moderate work. At moderate work load,,then, A q,.which i s oxygen intake at zero time of the recovery, assumes the value of oxygen income at steady state during exercise. Since there are i n d i v i d u a l differences i n the oxygen requirements for the same external work of mild or moderate degree, there should be a r e l a t i v e l y high c o r r e l a t i o n between A q (but not K) and the t o t a l metabolic cost of the work (42). In the two-component exponential system, formula 3,' the rate of oxygen intake at minute t of recovery i s —K t —K t s p e c i f i e d by A, e 1 + A„e 2 . w i t h A = A, + A 0. The 1 2 o 1 2 f i r s t term represents the a l a c t a c i d component of oxygen debt, with A^ and standing for the. rate of a l a c t a c i d oxygen 39 consumption i n recovery and al a c t a c i d v e l o c i t y or time constant, respectively. The second ternr of the function represents the l a c t i c component of oxygen debt, .with and standing for the rate of l a c t i c oxygen consumption i n recovery and. l a c t i c v e l o c i t y or time constant, respectively (10, 14 , 4 5 , 46 , 6 6 ) . Berg (10) has proved that there are i n d i v i d u a l differences i n the a l a c t i c v e l o c i t y constant K^. De Moor (1-4) studied the possible sex differences i n v e l o c i t y constants. Twenty-two men and 21 women performed a sub-maximal exercise on an e l e c t r i c b i c y c l e ergometer with the speed held constant. Oxygen consumption was measured and ind i v i d u a l two-component exponential recovery curves were treated s t a t i s t i c a l l y with reference to mechanical e f f i c i e n c y and sex differences." I t was observed that a l a c t i c oxygen debts and A^ and curve constants were not related to mechanical e f f i c i e n c y . Less e f f i c i e n t men and women have a larger lactate debt component, a larger proportion of lactate debt i n the t o t a l debt, a higher A ^ a n d a slower K 2 . Men have a faster a l a c t i c v e l o c i t y constant than women. There i s no sex difference i n the lactate debt v e l o c i t y constant or i n the amount of either a l a c t i c debt or lactate debt. Berg mentioned age factor as a possible influence on the rate of recovery. In his study (10) there was a 40 c o r r e l a t i o n between K 1 and age, due mainly to the f a s t K^'s of the youngest subjects and slow K^'s of the oldest subjects. The age range was 1 8 - 6 8 years. Within the age range 20 - 40, there was no appreciable c o r r e l a t i o n . Training E f f e c t of Oxygen Consumption i n Recovery,-Berg (10) has presented suggestive evidence that the i n d i v i d u a l differences i n the v e l o c i t y constants K are related to the e f f i c i e n c y of the c i r c u l a t i o n i n de l i v e r i n g oxygen to the tissues, even i n moderate exercise. This indicates that changes produced i n the i n d i v i d u a l i n the di r e c t i o n of improved oxygen supply to the tissues should leave steady state intake A rate unchanged i f the work i s unchanged, but v e l o c i t y constant K should increase and the si z e of the debt should decrease. Henry and Berg (43) have shown that a t y p i c a l a t h l e t i c conditioning program resulted i n decreasing the a l a c t i c oxygen debt r e s u l t i n g from a standard stool-stepping exercise, and also s i g n i f i c a n t l y speeded up the recovery rate. The mean A^ of 23 athletes before conditioning was 16.1 cc/min per unit of body weight, and af t e r conditioning, 14.9 cc. The difference, however, i s not s i g n i f i c a n t , since the t r a t i o i s only,1.5. The mean before conditioning was 1.40, and af t e r conditioning 1.52, a difference that i s s t a t i s t i c a l l y s i g n i f i c a n t above 1 percent p r o b a b i l i t y l e v e l . A regime o f - t r a i n i n g influenced the maximum oxygen intake 41' and the l e v e l of oxygen intake at which "excess lac t a t e " starts to appear i n the blood i n 13 Bantu male subjects i n a study by Williams et a l . (96).' Their r e s u l t s also show that these two parameters can change independently of each other. However, the finding that emerges most c l e a r l y i s that for the group as a whole, the percentage increase i n the l e v e l of oxygen' intake at which anaerobic metabolism occurs i s greater than the percentage increase i n maximum oxygen intake following a t r a i n i n g regime over four to sixteen weeks. Since the introduction of the l a c t a c i d - a l a c t a c i d concept of oxygen debt by.Margaria, Edwards and D i l l (66), physiologists (53,.65, 93) have attempted to r e l a t e these components to the oxygen recovery curves observed following exercise. However, much of t h i s research has been i n c o n f l i c t because investigators have been unable to quantita-t i v e l y separate oxygen debt into l a c t a c i d and a l a c t a c i d components at work loads that have resulted i n elevated blood l a c t a t e . There has been no suitable method which could be used to eliminate the involvement"of lactate i n oxygen debt,, thus allowing one to measure only, the a l a c t a c i d component of an oxygen debt. As a r e s u l t , there has been no universal agreement on the re l a t i o n s h i p between lactate removal and the excess oxygen consumption observed following exercise. 42 In view of t h i s c o n f l i c t , Barnard et a l . investigated the involvement of the Cori cycle i n oxygen debt. By blocking lactate removal by the l i v e r , oxygen debt.was reduced by approximately 44 percent. A reduction i n oxygen consumption during the l a s t minute of exercise was also noted. Thus, i t was concluded by investigators, that the l a c t a c i d and a l a c t a c i d components are involved i n oxygen debt when lactate i s being removed by the l i v e r following exercise. Thus, oxygen debts measured a f t e r blocking lactate removal by the l i v e r , are a good approximation of the a l a c t a c i d oxygen debt. In view of these findings, Barnard et a l . (9) extended t h e i r research on dogs to examine the e f f e c t of tr a i n i n g as well as various work loads on the l a c t a c i d and a l a c t a c i d oxygen debt components. The data obtained from the two dogs used i n the study c l e a r l y shows the e f f e c t of tr a i n i n g on l a c t i c acid production and, consequently, on the oxygen consumption during exercise as well as during recovery. During a l l the tests conducted a f t e r • t r a i n i n g , . . . the peak lactate values were much less than those observed p r i o r to t r a i n i n g . This was even" true at the higher workloads studied af t e r t r a i n i n g . The lactate concentration also returned to the r e s t i n g " l e v e l much sooner a f t e r t r a i n i n g . (9) The above findings agree with e a r l i e r works of C r e s c i t e l l i and Taylor (13). Since lactate accumulation was decreased as a r e s u l t of t r a i n i n g one would naturally expect the oxygen debts to"be, decreased. This was i n fa c t the case even at much higher work loads studied a f t e r t r a i n i n g , Oxygen debts for the two dogs at the heavy work load (6.5 mph, 20% grade) a f t e r t r a i n i n g were reduced by 44.6 and 54.5 percent from the nontrained debts at four mph, 20 percent grade. These findings from Barnard et, a l . substantiate pre-. vious observations by Baldwin (8) and by Henry and Berg (43) who have also reported a s i g n i f i c a n t decrease i n oxygen debt as a r e s u l t of conditioning programs. Barnard could not draw any d e f i n i t e conclusions regarding changes i n the a l a c t a c i d debt with t r a i n i n g . However, the data: obtained for one dog offered some in d i c a t i o n that t r a i n i n g did not s i g n i f i c a n t l y change the a l a c t a c i d oxygen debt. In conclusion, then, i t seems highly possible that trained individuals and animals give lower blood lactate responses and they may also have a greater capacity to u t i l i z e lactate once it'accumulates i n the blood. Therefore, i f less lactate i s being formed and more i s capable of being u t i l i z e d by other tissue i n addition to that removed by the l i v e r , less lactate remains to be converted back to sugar. As a r e s u l t , the oxygen consumption needed by the organism would be decreased during work and recovery. The observations made i n the l i t e r a t u r e suggest, then, that these adaptat ions are o c c u r r i n g as a consequence of t r a i n i n g . CHAPTER III METHODS AND PROCEDURES Introduction Eight v a r s i t y rowers were divided into two equally fas t "four-oar" crews (A and B) and assigned to two i n t e r v a l t r a i n i n g programs i n the late stages of preparation for the 19 72 competitive season. The t r a i n i n g lasted eight weeks. The rowers were tested on a rowing ergometer at the beginning, half way through, and at the end of the experimental period. Total work completed and recovery oxygen intake data were analyzed s t a t i s t i c a l l y to determine the differences. Subjects The-subjects (S) of the study were,crew members of the v a r s i t y eight at the University of B r i t i s h Columbia. It i s important.to note that the subjects represent a group of. highly motivated, e l i t e athletes who. had been i n rogorous t r a i n i n g for the Olympics six months pr i o r to the experimental period. In the two seasons p r i o r to the testing, they were Canadian Champions and represented Canada i n World and Pan American Championships. These oarsmen were dedicated and did t h e i r best when asked for a maximal e f f o r t . This co-operation was an absolute necessity for the rowing ergometer testing part of the study. 45 46 The eight oarsmen had been changed around for some time p r i o r to the experimental period with the purpose of attaining two equally f a s t crews at the beginning.of the experimental t r a i n i n g . One of the oarsmen from crew A broke his arm at the beginning of the t h i r d week of the experimental t r a i n i n g period and had to be replaced. Thus only seven subjects were experimentally treated i n t h i s study. A l l seven subjects were single university students with an average age, height and weight, of 21 years, 73 inches and 190 pounds, respectively.' The Design of the Training Programs Two crews of four rowers plus coxwain were assigned almost si m i l a r rowing t r a i n i n g programs which were carr i e d out at the same time and place,.under one coach. The tra i n i n g programs were d i s s i m i l a r only i n that late season anaerobic i n t e r v a l t r a i n i n g for eight.weeks was done with each crew using a d i f f e r e n t procedure i n the recovery phase between workbouts. In addition to i n t e r v a l workouts, the eight-week program included steady state rowing and anaerobic f a r t l e k rowing workouts. These were the same for both fours. A l l three types of workouts were organized i n the following fashion: 47 Period I (1st, 2nd, 3rd, and 4th week) 3 workouts -. steady state rowing 2 workouts - i n t e r v a l rowing 1 workout - anaerobic f a r t l e k Period II (5th, 6th, and 7th week) . 3 workouts - i n t e r v a l rowing 2 workouts - steady state rowing; 1 workout - power rowing Period III (8th week) 4 workouts - i n t e r v a l rowing 2 workouts - power rowing Interval training., program A. The crew A following program A was, by the end of the experimental t r a i n i n g period, expected to row 16 times 560 metres i n t e r v a l s i n the following fashion: Repetitions Distance Rest Period 4 X 560 m Rest period betw. bouts 8 min 4 X 560 m II •1 II II 6 min 4 . X 560 m II II H II 4 min 4 X 560 m it II M II 2 min Interval t r a i n i n g program B.. The crew B following program B was also expected to row 16 times 560 metres i n t e r v a l s but i n a q u a l i t a t i v e l y d i f f e r e n t fashion from the crews following program A, 4 8 Repetitions : Distance Rest Period 4 x 5 6 0 m Rest period betw. bouts 2 min 4 x 560 m " " II • H 4 m i n 4 x 5 6 0 m " " " " 6 min 4 x 5 6 0 m " " " " 8 min The rest periods' i n each i n t e r v a l t r a i n i n g workout.. either shorten or lengthen, depending on the program, thus allowing the rowers to keep the same racing pace or equal times under program B and gradually slower pace or slower times under program A as the workout would approach termination. Building up the work load i n i n t e r v a l workouts from the " i n i t i a l 4 x 5 6 0 m stage" to the " f i n a l 16 x 5 6 0 m stage" involved a gradual increase i n number of repetitions from four to 1 6 . Design of the Testing Program The experimental design allowed three, complete testings: i n addition to pre- and post-training t e s t i n g , there was one complete testing h a l f way through the experi-mental period. A l l three testings were carried out at the University of Washington. Upon a r r i v a l at the Experimental Laboratory one hour before the t e s t i n g , a S was asked to rest for 1 5 minutes and read the instructions for te s t i n g procedure (see Appendix A). Data c o l l e c t i o n procedure involved: 49 Rowing performance. The S assumed the normal rowing position on the rowing ergometer, adjusting the seat and s l i d e assembly and foot braces to conform to h i s wishes. Following an additional warmup for f i v e minutes on the ergometer, the S was then asked to do a one-minute a l l - o u t row., The number of ergs was recorded. After a short rest, the S executed a six-minute row at. the maximal possible e f f o r t . Work output i n terms of ergs was measured continuously throughout the six-minute exercise. Each S was required to obtain the maximal possible number of ergs at any desired stroke, r a t i n g . However, stroke rating was maintained by timing and verbal assistance from an experienced coxwain, to increase motivation. Recovery metabolism. For 15 minutes f the recovery metabolism was determined by open-circuit system. There were ten c o l l e c t i o n s made: every half a minute for the f i r s t two minutes, then every minute u n t i l the f i f t h minute and then from minute f i v e to seven,,seven to ten, and ten. to f i f t e e n . Subjective response to the t r a i n i n g session. After each i n t e r v a l t r a i n i n g session during the experimental period, each S completed one part of an e s p e c i a l l y designed questionnaire with fatigue scales. The second part was completed on the following morning, before the workout. At the end of the experimental t r a i n i n g period, the Ss submitted a written subjective response to the t r a i n i n g methods. 50 Apparatus Rowing, ergometer. The Leichar-ii': rowing ergometer i s a ruggedly constructed piece of apparatus. I t allows an operator to execute a rowing motion which simulates very c l o s e l y , both kinematically and dynamically, the actual motion experienced when rowing a boat. I t also permits the accurate measurement of the work output. In the Leichardt ergometer the S has his feet i n clogs and i s seated on a s l i d i n g seat. He operates a handle having the same dimensions as an oar handle, and which i s pivoted i n the position corresponding to that of a racing s h e l l . The handle i s connected to the drive t r a i n i n such a way that the S experiences the same r e s i l i e n c e as would be experienced with a r e a l oaf. The handle i s free to move not only h o r i z o n t a l l y , but v e r t i c a l l y and can rotate about i t s own axis thus allowing the S to duplicate any motion oh the machine that he would carry out i n a boat. The energy fed i n by the S i s absorbed by a f r i c t i o n brake, acting against a heavy fly-wheel. The siz e and speed of the -fly--, wheel are such that the percentage reduction i n speed between strokes corresponds clo s e l y to the percentage reduction i n speed of an actual boat between strokes; also the speed with which the S has to take his catch cl o s e l y approximates, to that i n a boat. The load applied to the fly-wheel i s such as to cause about the same rate of energy d i s s i p a t i o n as would occur due to the motion of the h u l l through water. 51 The fly-wheel brake i s s p e c i a l l y designed to maintain constant torque load over a wide range of speeds. With the application of constant torque load i t i s a r e l a t i v e l y easy matter to determine the work done by the S over a given period of time; the work output being given by the product of the load torque times the t o t a l angle turned through by the fly-wheel. The t o t a l angle i s read i l y measured by means of a revolution counter. One revolution corresponds to one erg. A l l of the rotating parts are mounted on generously sized b a l l bearings thus reducing unknown f r i c t i o n losses to a minimum. The accuracy with which the work output may be determined i s to within approximately - 1 percent of the true value; this accuracy being more than adequate to allow reasonable comparison of the potentials of various ind i v i d u a l s . See Figure 3, page 52. Open-circuit system equipment. The experimental S used a mouthpiece with nose c l i p to ensure a single d i r e c t i o n a l a i r flow by a set of two f l u t t e r valves. The expired a i r was led through f l e x i b l e p l a s t i c tubing of 3.5 cm i . d . into 300-liter and 180-liter Douglas-type polyvinyl chloride bags (W. E. C o l l i n s , Inc.). 0 2 and C0 2 percentages were determined paramagnetically (Beckman Instruments, Model E-2) and by infrared analysis (Lira 300, Mine Safety Appliances Co.), respectively, at the University of Washington Cardiology Department by an experienced T e s t i n g on the L e i c h a r t Rowing Ergometer; F r o n t and S i d e P o s i t i o n s . technician. Gas. volumes were measured spirometrically and appropriately corrected.. Fatigue scales. The two fatigue scales as used i n the questionnaire (see Appendix B) were adapted from the "Subjective Evaluation of Level of Work" scale used, by Astrand and his associates. The fatigue scale used immediately af t e r the i n t e r v a l t r a i n i n g session has seven level s with four written labels of tiredness (somewhat t i r e d t i r e d , very t i r e d and completely exhausted) dispersed evenly from 1 (somewhat tired) to 7 (completely exhausted). The second fatigue scale used includes s i x l e v e l s (from 0 to 5) of tiredness s t i l l f e l t by the Ss 24 hours afte r the t r a i n i n g session. "Not at a l l " - 0 i s followed by "very, very s l i g h t l y " - 1, " s l i g h t l y " - 2 and " f a i r l y l i g h t " - 4. Levels that a r e : l e f t blank accommodate any other state of tiredness not described by written l a b e l i n both scales. Testing Parameters The three experimental testings measured the following parameters of f i t n e s s : 1. ' Total work performance completed i n s i x minutes on the rowing ergometer i n terms of ergs. 2. Total oxygen consumption obtained i n ten c o l l e c t i o n s for 15 minutes. Subjective written responses about the state of fatigue were collected immediately after each i n t e r v a l t r a i n i n g session and 24 hours l a t e r . Written responses of the Ss to the training methods were obtained at the end of the experimental period. S t a t i s t i c a l Analysis A t h e o r e t i c a l exponential function of the form A = A^e 1 + A 2e 2 was f i t t e d to the observed oxygen debt pay-off values of each S by using "Non-linear Least Squares - BMD - X85" (82) computer program. Thus predicted values for each of the c o l l e c t i o n periods as well as the parameters of the fa s t (A^, K^) and slow (A 2, K^) component of the oxygen debt were obtained. The same exponential function was also f i t t e d to the average experimental data of a l l seven Ss i n testing 1 and to the average experimental data for method (A) and (B) i n a l l three testings. Predicted and observed curves for three individuals were plotted i n Figure 4 to examine goodness of f i t of the mathematical exponential function to the experimental data. This was necessary i n the absence of any previous experience about f i t t i n g of the above mathematical function to the data obtained aft e r a v i o l e n t a l l - o u t e f f o r t . Predicted and observed average oxygen debt curves for a l l Ss i n testing 1 and predicted average oxygen debt curves for t w° methods i n a l l three testings were plotted i n Figures 5 and 6. The parameters of oxygen intake curve i n recovery were treated s t a t i s t i c a l l y for testing the v a l i d i t y of Hypotheses 3 and 4. A repeated measure analysis of variance for a 2 x 3 f a c t o r i a l experiment was used by employing "General Linear Hypothesis - BMD - X64" (83) computer program: Source of Variation Degree of Freedom Training Method (M) 1 Subjects M (SwM) 5 Testing (T) 2 M x ' T 2 . • S M x T 10 w TOTAL 20 The same analysis of variance was used i n treating s t a t i s t i c a l l y the rowing performance and t o t a l oxygen debt for testing the v a l i d i t y of the General Hypothesis of the study as well as Hypotheses 1 and 2. To t e s t the v a l i d i t y of Hypotheses 5 and 6, medians were calculated from the observed data on the fatigue scales from the questionnaires and compared. A l l rowers were expected to improve t h e i r rowing performance as well as t h e i r t o t a l oxygen debt i n recovery afte r an eight-week t r a i n i n g program. Because of the supposed superiority of method A over method B the rowers 56 following t r a i n i n g program A were expected to show greater improvement i n these two parameters than rowers following t r a i n i n g program B. Any increase i n the t o t a l oxygen debt w i l l necessarily mean an increase i n one or more components of the oxygen debt curve. The nature of any improvement i n values of f a s t or slow components i n rowers' oxygen debt w i l l be r e f l e c t e d i n improvements i n A's and K's which quant i t a t i v e l y describe them. Testing of Hypotheses 3 and 4 (Chapter 1) was made i n accordance with the t h e o r e t i c a l basis which i s outlined i n the following paragraph. The fas t component of the oxygen debt curve w i l l , for example, improve (become bigger) i f : 1. Aj- increases with Kj unchanged; 2. decreases with A^ unchanged; 3. Aj^ increases and decreases; 4. both increase with A^ proportionally more than K^. The same combinations are equally possible for the slow component of. oxygen,,debt. Thus, improvement of t o t a l oxygen debt depends on many possible combinations of i t s parameters. From the limited l i t e r a t u r e related to the problem, the following i s known:. 1. In studies when mild exercise t e s t was given before and aft e r a period of t r a i n i n g , only the f a s t component of the oxygen debt, K, ,. increased and 57 remained unchanged. Total oxygen debt was reduced (10, 43, 45). . 2. In studies where subjects were given i n -creasing work tasks the higher work load ( s t i l l below maximum) increased the t o t a l oxygen debt more than the lower work load. Both slow and f a s t oxygen debt increased (improved). An improved f a s t component was accommodated by a higher A^ and an unchanged and a higher A^ and slower accommodated the improved slow component (10, 46). The l i t e r a t u r e on the e f f e c t of t r a i n i n g , on oxygen, debt and i t s parameters i n the f i n a l stages of preparation of athletes for competition i s non-existent. This study i s believed to be the f i r s t experiment of such nature. There-fore i.t was impossible to predict the possible changes of parameters of an -improved t o t a l oxygen debt. S t a t i s t i c a l s i gnificance i n method x te s t i n g interactions was analyzed by using Harter's multiple comparison procedure for interactions (37). The s i g n i f i c a n t range at the f i v e percent l e v e l for tests of ordered means two and three steps apart, with ten degrees of freedom for the standard error of the mean, were 3.15 and 3.88, respectively. Hence the range of a l l three i n t e r a c t i o n elements was judged s i g n i f i c a n t at f i v e percent l e v e l i f i t exceeded s^ x 3.88, that of two adjacent ordered in t e r a c t i o n elements was judged s i g n i f i c a n t at that l e v e l i f i t exceeded s^ x 3.15. The 2 1/2 2 value of s^ was obtained by ( 2 s /3) , where s represented error mean square. CHAPTER IV RESULTS AND DISCUSSION PART I: RESULTS Rowing performance scores and t o t a l oxygen consumption values are shown i n Table 3. Table 3 Rowing Performance (R.P.) Score i n Ergs/6 min and Total Oxygen (T.O.) Consumption Score i n L/15 min. Testing 1 Testing 2 Testing 3 Method Subject R.P. T. 0. R.P, T. 0. R.P. T. 0. M A S 1 1683 11. 008 1714 13. 822 1911 16. 481 M A S 2 169 8 10. 494 1851 10. 914 1934 13. 172 M A S 3 1647 11. 011 1731 11. 835 1872 12. 512 Mean 1676 10. 838 1765 12. 190 1905 14. 055 M B S 4 1648 11. 237 1735 12. 092 1822 13. 479 M B S 5 1682 •?:. 290 1725 9. 502 1817 10. 963 M B S 6 1718 10. 957 1822 11. 215 1899 11. 924 M B S 7 1584 11. 252 1775 11. 179 1887 12. 270 Mean 1658 10. 684 1764 10. 996 1856 12. 159 A l l Ss scored higher on the rowing performance over the 58 . 59 three t e s t s and showed a s t a t i s t i c a l l y s i g n i f i c a n t F (112.07, Table 4) over t r i a l s . -- Table 4 /Analysis of Variance for Rowing Performance Score Source of Variation d.f. Mean Square F P r o b a b i l i t y Method 1 2681.28 S M w 5 4307.66 Testing 2 157339.59 112.07 {.01 M x T 2 2062.45 1.469 J.01 S M x T w 10 1403.8 The single departure from a.progressive increase of oxygen debt values for a l l Ss over t r i a l s was S 7 at t e s t 2. The value of t o t a l oxygen debt for S 7 decreased i n testing 2 (11.170) over the value of oxygen debt attained i n te s t i n g 1 (11.252), but increased i n te s t i n g 3 (12.270). 60 Table 5 Analysis of Variance for Total Oxygen Debt Source of Variation d.f. Mean Square F P r o b a b i l i t y Method 1 6.009 1.687 >-05 S M w 5 4.763 Testing 2 19.401 37.05.8. {.01 M x T 2 2.634 5.032 < -05 S M x T w 10 .523 Subgroup means for method A and B for t o t a l oxygen debt and rowing performance were quite c l o s e l y matched at t e s t 1, but were d i f f e r e n t at t e s t 3, group A having the largest improvement i n both parameters. However, there was no s i g n i f i c a n t difference between the two methods used as shown by analysis of variance i n Tables 4 and 5. There was a s i g n i f i c a n t method x tes t i n g i n t e r a c t i o n for t o t a l oxygen debt values at .05 l e v e l of s i g n i f i c a n c e . Further investigation of the nature of t h i s i n t e r a c t i o n was not possible to determine since analysis of interactions did not y i e l d s t a t i s t i c a l s i g n i f i c a n c e for the ranges of the two adjacent and of a l l three ordered in t e r a c t i o n elements. Predicted and observed oxygen debt curves for Ss 2, 5, and 7 are plotted i n Figure 4 on page 62. The graphs demonstrate that the mathematical curve f i t t i n g was s u f f i c i e n t l y accurate to permit analysis by the method described i n Chapter I I I . Subgroup oxygen, debt curves for a l l three testings are shown, i n Figures 5 and 6 on pages 63 and 64. The curves approximate each other very cl o s e l y i n form, but method A curves in.testings 2 and 3 are above, the curves of method B. In t e s t i n g 1, method A curve started o f f higher, but took a lower position i n the l a t t e r portion. The mathematical curve A = A 1e K l t + A 2 e - K 2 t was f i t t e d to the experimental oxygen recovery data for each S for each of the three testings. The calculated values for A^, , , and for. a l l Ss are given i n Table 6 on page 65. The mean values for the subgroups i n Table 4 are the averages of the i n d i v i d u a l values. Between test i n g 1 and te s t i n g 3 there -is a general change i n numerical values of A's amd K's: the A's and the K^'s increased and the K^'s decreased, but there were exceptions. These exceptions were: For method A: A^ i n testing 2; i n t e s t i n g 3 increased over i n testing. 1, but not over i n t e s t i n g 2. For method B: A„ i n testings 2 and 3. F i g u r e 4 . P r e d i c t e d and Observed (broken l i n e ) Oxygen Debt Curves f o r t h r e e Ss i n T e s t i n g 1. Each Curve has a d i f f e r e n t b ase l i n e . .0 S 2 0 TIME OF RECOVERY: MINUTES S 5 ( e x e r c i s e ended a t time zero) 3.00. 2.00 1.00 Testing 1, Predicted Above: Below: Figure 5 Predicted Average Oxygen. Debt Curves for two Methods -in Testing 1. Predicted Average Oxygen Debt Curves for two Methods i n Testing 3 as Compared to Predicted and Observed (broken line) Total Average ( a l l Ss) Oxygen Debt "*"" -Curves in Testing 1. Testing 1, Observed 0 1 2 4 . 0 0 3 . 0 0 EH CQ W W Q EH (S3 °U fa O 05 fa W 0< EH 3 2 . 0 0 1 . 0 0 . Method A Method B Figure 6 ^Average Oxygen Debt Curves for Method A and Method B i n Testing 2. TIME OF RECOVERY: MINUTES (exercise ended at time zero) 10 11 12 Table 6 Predicted Oxygen Debt Parameters A^ and A2 i n L/min, and and K 2 i n min~i. T e s t 1 n g 1 T e s t i n g 2 T e s t i n g 3 Meth. S A l K l K 9 A l K l A-9 K 9 A1 K l A2 K2 A 1 3. 972 1. 594 .9384 .1163 3. 175 2. 846 2 .0917 .1840 4 .134 • 8434 .9483 .0542 A 2 4. 382 1. 172 .4891 .0922 3. 665 1. 014 .5070 .0592 5 .078 1. 3770 .8246 .0798 A 3 3. 129 • 810 .5276 .6396 3. 081 • 978 .8131 .0749 4 .080 1. 3840 .9387 .0838 Mean 3. 827 1. 192 .6517 .2826 3. 307 1. 613 1 .1373 .1060 4 .430 1. 2014 .9039 .0726 B 4 3. 837 1. 689 1.1267 .1470 4. 347 2. 030 1 .2734 .1376 4 .318 1. 4910 1 .1142 .0935 B 5 2. 378 • 650 .4115 .0765 2. 557 • 605 .2443 .0011 2 .696 • 9310 .0795 .0929 B 6 3. 274 1. 387 .8993 .0907 3. 436 1. 505 .8941 .0708 3 .942 1. 7070 1 .0020 .0783 B 7 4. 115 1. 601 .8591 .0836 3. 757 1. 467 .8103 .0673 4 .768 1. 9590 1 .0590 .0916 Mean 3. 401 1. 332 .8241 .0994 3. 524 1. 402 .8055 .0692 3 .941 1. 5220 .8137 .0891 66 The analyses of variance yielded no s i g n i f i c a n t F's for methods' e f f e c t for a l l four parameters. For parameter (Table 7, A) there was a highly s i g n i f i c a n t F (3.4.37) for t e s t i n g e f f e c t , and there was a s i g n i f i c a n t testing x method in t e r a c t i o n for A^ at -.01 l e v e l of si g n i f i c a n c e . In order to investigate further, the nature of th i s s i g n i f i c a n t finding Harter's procedure was used. The standard error of each i n t e r a c t i o n element (sg) was found to be .1918, The c r i t i c a l value for the range o f a l l three i n t e r a c t i o n elements was .744 (.1918 x 3,88) and for the range of two adjacent ordered.interaction elements .604 (.1918 x 3.15). The range between the f i r s t (difference between the subgroup means for A^ from te s t i n g 2) and the second (difference between the subgroup means for A^ from te s t i n g 1) value of ordered differences between the subgroup means for A^ from a l l three testings was .642. This range value was s i g n i f i c a n t since i t exceeded the c r i t i c a l value .604 and was the only s i g n i f i c a n t value. Thus the only s i g n i f i c a n t i n t e r a c t i o n was found to be between * tes t i n g 1 and tes t i n g 2. 67 Table 7 A. Analysis of .Variance for A Source of Variation d.f. Mean Square F Probab i l i t y Method 1 .287 .05 M x T 2 .2500 3.0604 ).05 S M x T w 10 .0816 " • . D. Analysis of Variance for K 2 Source of Variation d.f. Mean Square F P r o b a b i l i t y Method 1 .0175 1.0778 \ .05 S M 5 .0163 Te s t i ng 2 .0398 2.3665 \ . 0 5 M x T 2 .0267 1.5893 \ . 0 5 S M x T w 10 .0168 68 The results for subjective feelings of fatigue, Table 8, show s l i g h t l y higher values for crew A, both immediately aft e r the t r a i n i n g sessions and 24 hours l a t e r . Table 8 Median Fatigue Scores immediately aft e r t r a i n i n g 24 hours a f t e r t r a i n i n g Week Crew A . Crew B Crew A Crew B 1-6 4 3 1 0 6-8 6 4 3 1 Summary. The t h e o r e t i c a l exponential function was f i t t e d to the oxygen data i n recovery for a l l Ss. Parameters of the oxygen debt curve were derived and treated s t a t i s t i c a l l y with analysis of variance for repeated measures two by three f a c t o r i a l experiment. The only s i g n i f i c a n t F was found for t e s t i n g e f f e c t and method x t e s t i n g i n t e r a c t i o n e f f e c t for parameter A.^ . The Harter procedure was used to further investigate the nature of t h i s s i g n i f i c a n t i n t e r a c t i o n . Rowing performance and'total oxygen debt, values for a l l Ss were treated i n the-same'way as the parameters. There was s i g n i f i c a n t difference, between the testings, but not between the methods. S i g n i f i c a n t method x te s t i n g i n t e r a c t i o n was found for t o t a l oxygen debt values, but the exact nature of th i s i n t e r a c t i o n was not possible to determine. PART I I : DISCUSSION Nature of Rowing Test In experimental studies of the effects of short-term sp e c i a l t r a i n i n g on athletes who are already very f i t , i t i s extremely d i f f i c u l t to e l i c i t improved physical performance from testing to t e s t i n g . Psychological factors have considerable influence not only on i n d i v i d u a l scores during t e s t i n g , but also on each t r a i n i n g session p r i o r to the experimental t e s t i n g . If an improvement from an already high a t h l e t i c performance i s to be attained at the end of the experimental t r a i n i n g period, then a p a r t i c u l a r e f f o r t has to be made to secure high and consistent motivation. Individual willingness to exert maximally in:.:>training and t e s t i n g may change and t h i s may produce unreliable t e s t data. I t i s l i k e l y that the most w i l l i n g and co-operative oarsman could not, under the conditions of the study, develop the maximal power output reached during important races. Every element can be supplied a r t i f i c i a l l y i n experiments l i k e these, except one, i . e . , the intense combative emotion which i s necessary to drive each athlete close to his utmost physical a b i l i t i e s . This problem of e l i c i t i n g consistently the " a l l - o u t " performance i s an important one i n studies such as t h i s and must always force the investigator to experience caution 69 70 i n the interpretation of his r e s u l t s . The small groups used to. t e s t the s p e c i f i c hypothesis pose a rigour on the data which i s c r i t i c a l . A t ypical performance by one or two subjects can influence the res u l t s powerfully. In t h i s study the general trend was for rowing performance i n ergs to increase concomitantly with the t o t a l oxygen consumption i n recovery. Subject 1 from group A, however, increased his t o t a l oxygen consumption i n recovery a t y p i c a l l y (larger than typical) whereas his rowing performance remained t y p i c a l : Subject 7 (group B) increased his rowing performance r e l a t i v e l y more than the remaining subjects, but his t o t a l oxygen consumption i n recovery decreased i n tes t 2 -compared with test 1. If rowing exceeds other a t h l e t i c a c t i v i t i e s i n the amount of power output possible, the performance of the subjects i n t h i s study should approximate the maximum that : the human engine can a t t a i n . The conditions of t h i s study, therefore, were very d i f f e r e n t from those i n which subjects performed q u a l i t a t i v e l y d i f f e r e n t types of exercises under submaximal conditions. The te s t exercise used i n the present study was rowing ergometer work for six minutes at the maximum possible rate. I t i s probable that rowing i s a form of exercise i n which the t o t a l energy expenditure attainable for periods of s i x minutes i s greater than under any other conditions. No other exertion comes so near to involving the entire 71 muscle mass of the body i n maximal e f f o r t . Running i s mainly leg work; the arms are swung, but the c a l l on the muscles of the upper limbs i s comparatively small. The trunk muscles act mainly as ' f i x a t o r s . Although b i c y c l i n g and bench stepping exercise permit a large power output the mass of active muscle involved i s much smaller than i n rowing. The rowing stroke begins i n a p o s i t i o n of extreme fl e x i o n of trunk and legs and uses a powerful drive of the extensor muscles which are the stronger muscles of the body. The movement proceeds rapidly to f u l l extension, p u l l i n g throughout against the high resistance of the oar, and ends with a powerful f l e x i o n of the arms. From th i s p o s i t i o n , the recovery involves a rapid bending of the wrists, lowering the hands and shooting them forward, and a bending of ankles, knees, hips, waist and shoulders; th i s i s accomplished by contraction of p r a c t i c a l l y a l l the flexor muscles of these j o i n t s . Thus during the p u l l the greatest possible work i s obtained from the extensors of the trunk and legs and from the flexors of the arms, while-during the recovery the flexors of trunk and legs and the extensors of the arms, although less heavily loaded, are made to pass through a f u l l range of flexion-extension. This process i s repeated 30 or more times a minute. The majority of studies (10, 14, 43, 45, 47, 65, 66) on metabolic recovery from exercise (running, b i c y c l i n g or 72 bench stepping) have been related to submaximal exercise, the recovery from which may take several minutes only. In some studies (46, 47, 66), a more vigorous exercise was required. In these there appeared a slow component of post-exercise intake, but t h i s approached the base l i n e f a i r l y quickly. In 25 minutes of recovery following a six-minute b i c y c l i n g exercise at 680 kgm/min De Moor (14) obtained a mean value of t o t a l oxygen debt for .22 men of 2.528 L whereas in t h i s study the mean valuer of oxygen debt c o l l e c t e d over 15 minutes was 14.005 L (method A) and 12.159 L (method B) in the l a s t t e s t i n g . In an experiment by H i l l (4.7) the oxygen debt c o l l e c t e d for one and one half hours aft e r the end of a ten-minute exhausting run was 12.5 L for a f a i r l y trained subject. In contrast, 16.4 L was the highest i n d i v i d u a l value (S 7) of oxygen debt and 9.29 L was the ',. lowest (S 5) one i n thi s study (15 minute c o l l e c t i o n only). Oxygen Intake i n Recovery - (Debt) Curves In order to show the nature of the oxygen consumption curves i n recovery, the in d i v i d u a l curves for three Ss have been drawn-in one diagram (Figure 4).; each i s pl o t t e d from i t s own sp e c i a l base l i n e which represents the f i n a l r e s t i n g oxygen intake. The three curves are remarkably a l i k e . In every case, aft e r the vigorous rowing exercise l a s t i n g s i x minutes,-the recovery oxygen intake f a l l s from i t s high . i n i t i a l value very rapidly i n the f i r s t two minutes of the recovery phase. There i s an obvious and large residual debt which declines slowly over the entire recovery period. I t asymptomatically approaches the base l i n e , but i s s t i l l well above i t a f t e r 15 minutes of recovery. These observations are very much in agreement with a l l the studies dealing with oxygen consumption i n recovery (14, 43, 44, 45, 47). In t h i s , there are c l e a r l y two factors at work - -one which accounts for the i n i t i a l rapid f a l l i n the oxygen intake on the cessation of exercise, and another which i s related to the prolonged residual recovery debt which i n t h i s experiment does not reach the base l i n e u n t i l a f t e r 15 minutes. Each process i s exponential i n character - one i s rapid; one, however, i s slow. As reported i n the l i t e r a t u r e , moderate exercise i s followed, to a preponderant degree, by recovery of the rapid type (10, 45). After quite gentle exercise,, the recovery process i s presumably even quicker than the most rapidly f a l l i n g curve shown i n the studies by Berg and Henry (10, 43). In t h i s present study, i t i s clear that the second stage of the recovery process requires a long recovery period for i t s completion. This phenomenon has been observed and discussed by Margaria (66), H i l l et a l . (4.7) , and others (7) . I t may take several hours f o r the 74 metabolism to reach resting l e v e l following a vigorous exercise such as rowing. The work of Margaria, Edwards and D i l l (66) and the e a r l i e r investigation of H i l l et a l . (47) has led to the fr a c t i o n a t i o n of the oxygen debt pay-off curve into two components that may be described as the sum of two t h e o r e t i c a l exponential terms, A^e K l ^ , and K^e K 2 t . The close agreement of the t h e o r e t i c a l curve with . the experimental results shown i n Figure 4 i s f a i r l y convincing, since the formula for oxygen consumption has only four parameters and there are only ten experimental points i n the 15-minute recovery period chosen i n t h i s study. The f i t i s not as good as reported by Henry and his colleagues (43, 45) af t e r mild exercise where only the f a s t component of the oxygen debt i s observed. In Henry's work when a heavier work load ( s t i l l submaximal) was introduced, which demanded an appearance of the slow component, a bigger scatter of experimental points was noticed (45), p a r t i c u l a r l y at the bend of the curve. Berg (10) also reported s i m i l a r considerable fluctuations from the t h e o r e t i c a l curves. The deviation of observed data from t h e o r e t i c a l data varies from i n d i v i d u a l to i n d i v i d u a l and i s presumably caused by uneven v e n t i l a t i o n and the changing of i n t r i n s i c factors i n the i n d i v i d u a l (10). In Figure 4 the greatest f l u c t u a t i o n of observed data i s exhibited by 75 S 7 and S 5, and the least v a r i a t i o n by S 2. I t i s possible that a better f i t could be obtained by using a more complex exponential function of the same form.. The use of mean scores for t e s t 1 ( a l l seven Ss) generates a much better f i t of the th e o r e t i c a l curve to the observed data; the observed mean data present a smooth l i n e as opposed to the ir r e g u l a r l i n e s of the observed values for single individuals (Figure 5, p'ag.en>63) . Rowing Performance/ Total Oxygen Debt, and the Parameters of the Oxygen Debt Curves: , A^, , K 2 The a b i l i t y to use objective mathematical r e l a t i o n -ships to observe the patterns of oxygen consumption i n recovery allowed H i l l et a l . (47) and Margaria et a l . (6.6) to fractionate the oxygen debt phenomena into components. Since there are d e f i n i t e l y two d i f f e r e n t mechanisms involved i n recovery, fr a c t i o n a t i o n of recovery oxygen into i t s a l a c t a c i d or f a s t and l a c t a c i d or slow component allows ca r e f u l studying of t h e i r responses to exercise and t r a i n i n g . Each i s described by two parameters A and K; A being the amount of oxygen used at the very beginning of exercise, and K representing i t s time or y e l o c i t y constant. If A^ + A 2 represent the r e l a t i v e amounts of oxygen intake that are removing oxidizable substrate (42) created during exercise by a l a c t a c i d and lactacid,mechanisms at minute zero of recovery, they must also represent the corresponding functions at the end of the exercise, whatever they might be. 76 The results for a l l the rowers as a single group -show improvement i n t o t a l oxygen consumption i n recovery, i n rowing performance and i n the a l a c t a c i d f r a c t i o n of the oxygen intake at the termination of the exercise over the eight-week i n t e r v a l t r a i n i n g program. The a l a c t i c v e l o c i t y constant shows e s s e n t i a l l y no change. The l a c t i c f r a c t i o n A 2 and l a c t i c v e l o c i t y constant K 2 also show 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 change. Although t h e i r respective F values (2.77 for A 2 and 2.36 for K 2) are not small, the average values of A 2 for method A and method B increased from the i n i t i a l average values of .65 and 1.09, to .90 and 1.32 L/min. K 2 for both methods decreased from i t s average values of 1.2 8 and .13 to .07 min for method A and .11 min ^ for method B. The nature and d i r e c t i o n of changes of the oxygen debt parameters i n t h i s study over the eight-week i n t e r v a l t r a i n i n g programs (group A and B combined) are i n agreement with previous research by Henry and De Moor (45) and Berg (10), although these men had investigated very d i f f e r e n t prob.lem;'they were interested i n the problem of s t a b i l i t y 4-and the progressive change i n the A's and K's due to a progressive increase i n work loads. The d i f f e r e n t work loads caused considerable differences i n the amounts and proportions of the fa s t and slow components of oxygen debt. As the work load increased, the a l a c t i c v e l o c i t y constant K, showed e s s e n t i a l l y no change, but the value of 77 l a c t i c v e l o c i t y constant K 2 became progressively smaller. The a l a c t i c f r a c t i o n A^ of the steady state oxygen intake changed considerably with the work load. The l a c t i c f r a c t i o n A 2 also increased, but less rapidly. An increased load e l i c i t e d an increase i n oxygen debt which was accommodated by a change i n A^ and constant to account for a larger a l a c t a c i d f r a c t i o n and an increase i n A 2 and K 2 to account for an increased l a c t a c i d f r a c t i o n of the t o t a l oxygen debt. However, the main change i n the slow component was due to a l t e r a t i o n of K 2. Total oxygen debt i n t h i s study increased s i g n i f i c -antly for the combined groups a f t e r eight'weeks of t r a i n i n g (F = 37.05). The increase i n the a l a c t a c i d f r a c t i o n of the t o t a l debt was accommodated with s i g n i f i c a n t l y increased A^ (F. = 34.270) and the apparent increased l a c t a c i d f r a c t i o n was accommodated by a simultaneous increase i n both parameters responsible for the slow component of oxygen debt, i.e.-A 2 and K 2. The apparent changes i n these two parameters were not s t a t i s t i c a l l y s i g n i f i c a n t (respective F values were 2.77 and 2.36) , but were i n the directions where the l i t e r a t u r e suggest they should go. Henry and Berg (43) have shown that decreased due"to tr a i n i n g and A^ remained unchanged under testing conditions using moderate exercise and the same rate of work for each t e s t . The authors stated that the t o t a l metabolic cost rose more''.than the increased physical ' 78 performance. I t i s most l i k e l y that maximal oxygen intake remains constant i n highly trainee! athletes over the l a t e periods of the season, despite increasing work loads.. If t h i s i s so, increased a l l - o u t performance under standard-ized condition i s possible only by means of attaining a higher oxygen debt. This debt should increase proportionally more than the work performance because i t i s an i n e f f i c i e n t method of providing for the metabolic cost of exercise. The r e s u l t s i n the present study agree with t h i s proposition; The.rowing performance scores for method A increased by.13 percent over the eight-week period; but the t o t a l oxygen debt values increased by 23 percent over the same time i n t e r v a l . A l l Ss Improved t h e i r oxygen consumption i n recovery over the eight-week'interval. S 1 showed the biggest gain of 4.4 L and S 7 showed the smallest gain of 1.4 L over t h i s period of time. Where physical performance i s improved due to t r a i n i n g and there i s no change i n e f f i c i e n c y there w i l l be a concomitant increase i n oxygen consumption. The more vigorous the exercise the greater becomes the importance of the oxygen debt part of t h i s oxygen cost. The oxidizable substance that i s created during the exercise w i l l accumulate, minute by minute, to the extent that the oxygen requirement exceeds A^ + • Thus, any p o s i t i v e e f f e c t that t r a i n i n g might, have on the physical performance and i n turn on t o t a l oxygen debt w i l l be confounded with the p o s i t i v e e f f e c t s that t r a i n i n g might have on the factors of the two 79 oxygen debt components (alactacid and l a c t a c i d ) . The general hypothesis of the study has been supported by the results since the subjects as a whole s i g n i f i c a n t l y improved rowing performance and t o t a l oxygen debt i n the eight-week period of i n t e r v a l t r a i n i n g . Discussion on Changes i n A-^ +A^ Due to Training i n Exhausting Exercise In Henry's study (46) rate of oxygen consumption at zero time i n recovery (A.^ + A 2) equals the steady state oxygen- consumption at termination of exercise. Higher i n t e n s i t y of work requires a higher steady state oxygen consumption thus an increased A^ + A 2 value at higher work load i s e a s i l y explained. In exercise where subjects are working at, highest possible work l e v e l with an oxygen consumption at i t s physiological maximum l e v e l as was the case i n t h i s experiment, i t becomes extremely d i f f i c u l t to explain a s i g n i f i c a n t increase i n A^ and a mild increase of A,,. A-^ + A 2 have to equal oxygen consumption at termination of work whether i t be submaximal or maximal. Obviously i t cannot go beyond the maximal aerobic power (maximal oxygen intake). Jackson (55) as well as others (7) have shown that maximal oxygen consumption i n trained athletes does not change due to additional t r a i n i n g . Thus, a higher maximal oxygen consumption curve i s highly un-l i k e l y to accommodate a s i g n i f i c a n t l y improved A,. 80 The only possible explanation for higher + A^ value i n l a s t testing i s yielded by the " l a s t minute oxygen, consumption phenomenon" i n exhausting exercise. I t i s known from previous research (55, 7) that the oxygen consumption i n the l a s t minute of exhausting exercise i s f a l l i n g from i t s preceeding maximal attained values although a high work load could s t i l l be maintained by the athlete for a l i m i t e d period of time.: This lower oxygen consumption at the termination of exercise causes a lower A 1 + A 2 a t zero recovery time. It seems a p o s s i b i l i t y that i n peak t r a i n i n g periods the "drop-off" i n oxygen intake i n the l a s t stages of exhausting exercise diminishes and the oxygen> intake at the termination of the exercise may be i d e n t i c a l with the maximal aerobic power and may account for the changes i n t o t a l group values for A^ +• A^. obtained i n t h i s study. The occurrence of t h i s peaking phenomenon i s supported by an additional experiment of the writer with the same Ss during the early summer of 1972. A l l Ss were tested e/ery four weeks for four times on the b i c y c l e ergometer; they rode the b i c y c l e u n t i l exhaustion. The i n i t i a l work load of 1500 kgm/min was progressively increased every two minutes by 500 kgm/min and oxygen consumption was measured continuously during the exercise. Only i n the l a s t t e s t , where a l l rowers reached the very maximum of t h e i r 81 potentials (five days before Canadian Olympic T r i a l s ) did t h e i r oxygen consumption i n the l a s t minute remain at maximum. This was i n contrast t o trie other tests when the majority, of oxygen consumption values dropped i n the l a s t minute. The physical performances improved as well at tes t .4',. but the maximal, oxygen consumption did not improve s i g n i f i c an t l y . The a b i l i t y to use objective mathematical r e l a t i o n -ships to quantify and p a r t i t i o n oxygen intake i n recovery makes i t possible t o arrive at a better understanding of the dynamics of the oxygen debt and i t s response to exercise and a t h l e t i c t r a i n i n g . Interval Training- Methods A and B The study has demonstrated that c a r e f u l l y c o l l e c t e d physiological data from a'controlled a l l - o u t exercise bout w i l l conform very p r e c i s e l y to a predicted t h e o r e t i c a l curve. Just as importantly, the study extends the e a r l i e r work of Henry (42, 43, 46) and his colleagues, showing that oxygen uptake following heavy work f a l l s under the same mechanisms of physiological control as oxygen uptake during work of a light, to moderate i n t e n s i t y . When the average oxygen debt curves (test 1) are plotted for groups A and B (Figure 5, Above), i t i s observed that method A curve starts o f f higher and i s above the method B curve for the f i r s t two minutes of the recovery. After that point i t runs below i t u n t i l the end of the recovery phase. 82 Aft e r four weeks of t r a i n i n g , the average oxygen debt curve for method A i s at no point below the average curve for method B (Figure 6).- After eight weeks of t r a i n i n g the discrepancy between the two curves becomes even greater i n favor of the average'oxygen debt curve for' method A. These graphs demonstrate an apparent greater improvement of group A over group B i n t o t a l oxygen debt a f t e r eight weeks of i n t e r v a l t r a i n i n g . The r e s u l t s of the study c l e a r l y show that there are 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 two methods i n any of the. measured parameters. A l l F values are quite low. The highest F r a t i o i s for t o t a l oxygen debt (1.68) and for (1.07); a l l other values are well below 1. Thus, a l l s p e c i f i c hypotheses but two were rejected. The data i n Table 8 show that rowers following method A reported s l i g h t l y higher, values for subjective feelings of tiredness immediately af t e r rowing and on the following day. A l l the rowers were quite f a m i l i a r with use of fatigue scales since s i m i l a r scales were used a f t e r almost a l l t r a i n i n g sessions during the previous two summers. For t h i s reason the rowers should have a r e l i a b l e i n t r i n s i c subjective evaluation of t h e i r tiredness a f t e r the t r a i n i n g sessions. The r e s u l t s shown i n Table 8 were i n accord with stopwatch record of rowing times during i n t e r v a l t r a i n i n g 83 sessions. Crew B had s l i g h t l y faster average times i n almost a l l i n t e r v a l sessions. The noticeable difference, however, was shown i n the l a s t two weeks of the experimental period when the i n t e r v a l sessions became longer and more frequent. Crew A seemed to accumulate tiredness from i n t e r v a l work session to i n t e r v a l work session and a few times they had to be sent o f f the water having done less repetitions than required by the.program. In contrast to r e s u l t s on the water during the t r a i n i n g sessions, crew A showed apparently higher work performance scores on the rowing ergometer a f t e r eight weeks of t r a i n i n g . Group means for rowing performance were quite c l o s e l y matched at test 1 (1676 and 1658 ergs), but were d i f f e r e n t at test 3 (1905 and 1856 ergs) i n favor of method A. However, analysis of variance yielded a non-s i g n i f i c a n t F value. The' F value for the difference between the methods i n t o t a l oxygen consumption yielded a non-significant value. However, by inspection of Figure 5 and Figure 6 i t i s observed that method A did e l i c i t s l i g h t l y greater t o t a l oxygen debt than method B. In test 1 the predicted average oxygen curve of method A was below the predicted average oxygen curve of method B a f t e r two minutes of the recovery (Figure 5, Above); t h i s changed i n the subsequent testings. In the l a s t t e s t i n g , the average method A curve i s well 84 above the average oxygen curve of method B for i t s e n t i r e length (Figure 5, Below). The same phenomenon occurred i n testing 2 (Figure 6). Group means for t o t a l oxygen consumption were quite c l o s e l y matched at te s t 1 (10.83 and 10.68 L)", but were d i f f e r e n t at te s t 3 (14.05 and 12.15 L) i n favor of method A. Two important factors might" have had c r u c i a l bearings on the. experimental r e s u l t s : 1. One S from crew A had to be replaced which caused problems of the adjust-ment of crew A to the new member. I t took almost three weeks for crew A to regain i t s previously established boat moving a b i l i t y . During that time, although the crew followed the program r i g i d l y , the crew members were not able to achieve f u l l exhaustion a f t e r every bout ( a l l - o u t e f f o r t i n each of the bouts was the chief requirement of the experiment). 2. Any experimentally demonstrable improvement i n performance and recovery oxygen intake was made d i f f i c u l t because of the high state of physical condition achieved by the rowers p r i o r to the experimental period. Under such conditions any differences between the two methods that might have been created should be d i f f i c u l t to show and would be expected to be small. In t h i s study the results showed no difference between the t r a i n i n g method A and t r a i n i n g method B. S p e c i f i c hypotheses 1, 2, 3, and 4 were not supported. The r e s u l t s obtained,, however, were i n the d i r e c t i o n 85 expected by the stated hypotheses. These findings support the experience of the investigator who coached both crews, i . e . , that method A i s worth p e r s i s t i n g with i n rowing t r a i n i n g and also i n further studies, p a r t i c u l a r l y - w i t h more subjects to i n v e s t i g a t e ' i t s e f f i c a c y further. In t h e i r written responses to the t r a i n i n g methods at the end of the experimental period a l l - S s stated that they were generally happy with the respective i n t e r v a l t r a i n i n g methods used i n t h i s study. The improved rowing performance and good f e e l i n g of. the Ss at the end of the experimental period supported the views of the rowing and track experts (1, 17, 30, 64, 77, 80, 97) that i n t e r v a l t r a i n i n g i s necessary i n the l a s t stages of the preparation of athletes for competition. Training at.racing pace i s advisable with i n c l u s i o n of workouts of high anaerobic f a r t l e k rowing where maximal rating at maximal possible speed i s attained by-the crew. CHAPTER V SUMMARY AND CONCLUSION The purpose of t h i s study was to determine whether or not one t r a i n i n g procedure used i n the preparation of v a r s i t y rowers for competitive rowing i s superior to another. Improvement i n t o t a l work performance on the Leichart rowing ergometer, improvement i n oxygen debt and subjective responses of the rowers to the methods were used as c r i t e r i a i n judging the su p e r i o r i t y of one method over the other. Improvement i n the slope ,and the rate of . the fa s t phase and slow phase of the oxygen debt curve provided additional c r i t e r i a . Eight v a r s i t y rowers were divided into two equally fa s t "four-oar" crews and assigned to two i n t e r v a l t r a i n i n g programs i n the late-stages of. preparation for competitive season. Subsequently one subject had to be replaced, therefore only seven subjects were •experimentally treated. A l l rowers were expected to improve t h e i r rowing performance as well as t h e i r t o t a l oxygen, debt a f t e r an eight-week t r a i n i n g program. The rowers following t r a i n i n g program A were expected to show greater improvement i n these two parameters than rowers following t r a i n i n g program B. Ad d i t i o n a l l y , greater improvement'in the slope and rate of oxygen intake of fas t and slow component of the oxygen debt 86 87 curve was expected from the rowers under program A. After each i n t e r v a l t r a i n i n g session they would subjectively expe-rience a higher state of fatigue. The three experimental testings measured t o t a l work performance completed i n s i x minutes and t o t a l oxygen consumption obtained i n 15 minutes of recovery. Subjective written responses to the t r a i n i n g sessions were c o l l e c t e d on d a i l y basis. A t h e o r e t i c a l exponential function of the form —K" t —K t A = A-^ e 1 + A 2e 2 was f i t t e d successfully to the observed oxygen debt pay-off values of each subject with the purpose . of obtaining the predicted values for c o l l e c t i o n i n t e r v a l s and the parameters that describe slow and fas t components of oxygen debt curve, A^, K^, A 2, and K2- Analysis of variance was used i n order to study the e f f e c t of t r a i n i n g and the e f f e c t of the two t r a i n i n g methods on the experimental subjects. The results showed that there was a s i g n i f i c a n t s t a t i s t i c a l improvement over t r i a l s i n rowing performance, t o t a l oxygen debt and A^ parameter of oxygen debt curve for the rowers as a t o t a l group. There was no s i g n i f i c a n t difference between the two t r a i n i n g programs i n any of the : t e s t parameters. The re s u l t s obtained, however, were i n the d i r e c t i o n expected by the stated hypotheses. The conclusions were as follows: 1. There was no s i g n i f i c a n t difference between the two methods used. 88 2. The eight-week rowing program, with concentration on i n t e r v a l t r a i n i n g , s i g n i f i c a n t l y improved rowing performance and t o t a l oxygen debt of the subjects. —K t 3a. The t h e o r e t i c a l function of the form A = A^e 1 + —K t A 2e 2 successfully f i t t e d the experimental oxygen debt data. 3b. Oxygen debt curves a f t e r an exhaustive rowing exercise were si m i l a r i n shape to curves obtained i n moderate exercise by other experimenters. 3c. The changes shown by the oxygen debt curves due to t r a i n i n g are si m i l a r to changes, on oxygen debt curves generated by increasing work loads i n submaximal conditions.' 4. The increase i n A^ + A 2 was presumably due to a b i l i t y of subj ects to maintain a higher oxygen consumption i n terminal stage of work. 89 LITERATURE CITED Adam, K., "The Adaptation of the C i r c u l a t i o n and Muscle Endurance," Ratzeburg Rowing .Clinic 1970, Princeton University, October 9 -13, 1970, Huntsville: University of Alabama Press, 1970. Adam, K., "Power Training of Oarsmen," Ratzeburg Rowing C l i n i c 1970, Princeton University, October 9 - 13, 1970, Huntsville: University of Alabama Press, 1970. Adam, K., "Intervals and Crew Selection," Rowing, 14:27-29, May, 1968. 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Wilt, F., "Vladimir Kuts," How They Train, Los Altos, C a l i f o r n i a : Track and F i e l d News, 1970, 83-86. APPENDIX A INSTRUCTIONS FOR TESTING PROCEDURE Rest for 15 minutes i n supine po s i t i o n . Change your clothes and weigh i n . Warm-up: 10 minutes jogging - stretching 5 minutes rowing on ergometer 1 minute a l l - o u t row (recording) 3-5 minutes rest Testing; A. a l l - o u t row .for 6 minutes B. c o l l e c t i o n of expired gases for 15 minutes. 99 APPENDIX B FATIGUE SCALE QUESTIONNAIRE Date: Name: How many hours did you sleep? What was your pulse rate: i n the morning? before bed? What was your weight: before workout? af t e r workout? State degree of general tiredness s t i l l f e l t from your l a s t workout:. 0. not at a l l . -1. . very, very s l i g h t l y .__ 2. 3. s l i g h t l y _______ 4 . f a i r l y l i g h t 5 . Other comments on your feelings on health i n general before workout, e.g., sleepy, sore throat, sore muscles, etc. .. . Did you enjoy the workout? ( i f not why?) . . State the f e e l i n g of tiredness: 1. somewhat t i r e d 2. 3. t i r e d 4 . 5 . . very t i r e d • -.-6 . 7. completely exhausted