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Electronic versus mechanical loading in the determination of peak oxygen consumption in bicycle ergometry Clarke, Mark Anthony 1980

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ELECTRONIC VERSUS MECHANICAL LOADING IN THE.DETERMINATION OF PEAK OXYGEN CONSUMPTION IN BICYCLE ERGOMETRY A THESIS SUBMITTED IN PARTIAL.FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION i n THE FACULTY OF GRADUATE STUDIES (School o f P h y s i c a l E d u c a t i o n and R e c r e a t i o n ) We a c c e p t t h i s t h e s i s as con f o r m i n g t o t h e r e q u i r e d s t a n d a r d THE UNIVERSITY OF BRITISH COLUMBIA B.P.E., U n i v e r s i t y o f B r i t i s h Columbia, 1976 (ARK ANTHONY CLARKE A p r i l 1980 Q Mark Anthony C l a r k e , 1980 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h C olumbia, I a g r e e t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department The U n i v e r s i t y o f B r i t i s h Columbia 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 DE-6 BP 75-51 1 E i i ABSTRACT The purpose o f the s t u d y was t o determine i f d i f f e r e n c e s i n the l o a d i n g ( o r b r a k i n g ) systems o f two d i f f e r e n t t y p e s o f s t a t i o n a r y b i c y c l e ergometers (Monark and D y n a v i t models) i n f l u e n c e d the performances o f s u b j e c t s i n s i m i l a r submaximal and maximal e x e r c i s e . A maximal t r e a d m i l l t e s t , a l s o performed by the s u b j e c t s , was used as a c r i t e r i o n measure w i t h which t h e maximal b i c y c l e ergometer t e s t r e s u l t s were compared. The p o s s i b i l i t y o f f i n d i n g d i f f e r e n c e s i n the performances o f s u b j e c t s on the two b i c y c l e ergometers and o f s i m i l a r i t i e s between maximal b i c y c l e and t r e a d m i l l t e s t s would appear t o have i m p o r t a n t i m p l i c a t i o n s f o r l a b o r a t o r y and f i e l d t e s t i n g p r o c e d u r e s , as w e l l as f o r c o s t s o f equipment used i n p h y s i c a l f i t n e s s work and e x e r c i s e p h y s i o l o g y . T h i r t e e n n o n - t r a i n e d , c o l l e g e - a g e d male v o l u n t e e r s , 18 t o 26 y e a r s , took p a r t i n the s t u d y . Each s u b j e c t performed one t e s t on each o f t h r e e p i e c e s o f t e s t i n g equipment; the D y n a v i t b i c y c l e , the Monark b i c y c l e , and the t r e a d m i l l . Each t e s t c o n s i s t e d o f a maximal e x e r c i s e bout o f a c o n t i n u o u s , i n c r e m e n t a l n a t u r e , d u r i n g which time the a p p r o p r i a t e p h y s i o l o g i c a l d a t a was r e c o r d e d . T h e r e was an i n t e r v a l o f a t l e a s t t h r e e days between t e s t s , the s u b j e c t s b e i n g a s s i g n e d t r e a t m e n t o r d e r s v i a a L a t i n square d e s i g n . P r i n c i p a l v a r i a b l e s examined d u r i n g maximal e x e r c i s e were t o t a l work time and peak oxygen consumption; a t submaximal e x e r c i s e l e v e l s t h e y were oxygen uptake and h e a r t r a t e . Other v a r i a b l e s examined, a l t h o u g h n o t o f c e n t r a l importance t o the s t u d y , were maximal h e a r t r a t e , maximal oxygen p u l s e , submaximal oxygen p u l s e , and s u b j e c t i v e response t o e x e r c i s e . A Beckman M e t a b o l i c Measurement C a r t , i n t e r f a c e d w i t h a H e w l e t t - P a c k a r d Data A c q u i s i t i o n system, r e c o r d e d the p e r t i n e n t p h y s i o l o g i c a l d a t a , which i i i was then a n a l y z e d b y t h e use o f one. and two-way ANOVA's and Newman-Keuls pos t hoc t e s t s where a p p r o p r i a t e . The r e s u l t s i n d i c a t e d no s i g n i f i c a n t d i f f e r e n c e s i n t o t a l work t i m e , peak oxygen consumption', maximal h e a r t r a t e , maximal oxygen p u l s e , submaximal h e a r t r a t e , submaximal oxygen uptake, submaximal oxygen p u l s e , and s u b j e c t i v e r e s ponse to e x e r c i s e between the two b i c y c l e e r g o m e t e r s . Only the t r e a d m i l l e l i c i t e d h i g h e r v a l u e s o f peak oxygen consumption than e i t h e r o f the c y c l e e r g o m e t e r s . T h i s Tack o f a s i g n i f i c a n t d i f f e r e n c e s u g g e s t s t h a t a l t h o u g h t h e r e may be s t r u c t u r a l d i f f e r e n c e s i n t h e l o a d i n g ( o r b r a k i n g ) systems o f the D y n a v i t and Monark e r g o m e t e r s , t h e s e d i f f e r e n c e s a r e n o t r e f l e c t e d by the subjects'* p h y s i o l o g i c a l r e s p o n s e s t o comparable l e v e l s o f e x e r c i s e i n t e n s i t y . Thus the r e s u l t s i n d i c a t e t h a t t h e s e b i c y c l e s c o u l d be used i n t e r c h a n g e a b l y f o r such p r e d i c t i v e t e s t s o f p h y s i c a l work c a p a c i t y as the Astrand-Ryhming P r e d i c t e d Oxygen Uptake T e s t o r the M o d i f i e d S j o s t r a n d PWC T e s t . i v TABLE.OF CONTENTS Ch a p t e r Page ABSTRACT i i LIST OF TABLES v i LIST OF FIGURES v i i ACKNOWLEDGEMENTS . . . . . v i i i I STATEMENT OF THE PROBLEM 1 I n t r o d u c t i o n 1 The Problem 3 Sub-Problems • . 4 Hypotheses 4 Importance o f the Study . . . . . 4 Assumptions and L i m i t a t i o n s . 5 Del i m i t a t i o n s . . . . . 6 D e f i n i t i o n s 7 II REVIEW OF THE LITERATURE 9 F a c t o r s R e l a t e d t o the D e t e r m i n a t i o n o f Maximal Oxygen Uptake 9 B i c y c l e Ergometry and Maximal E x e r c i s e ^ . D y n a v i t V e r s u s Monark i n Maximal and Submaximal E x e r c i s e 15 I I I METHODS AND PROCEDURES 21 S u b j e c t s 21 Apparatus 21 E x p e r i m e n t a l C o n d i t i o n s 24 E x p e r i m e n t a l P r o c e d u r e s 26 E x p e r i m e n t a l Design 27 E x p e r i m e n t a l A n a l y s i s . . . 29 V TABLE OF CONTENTS Chapter Page IV RESULTS AND DISCUSSION . . . . . . . . . 30 A n t h r o p o m e t r i c Data 30 T o t a l Work Time 31 Peak Oxygen Consumption 34 Submaximal Oxygen Uptake 38 Submaximal Heart Rate . 41 Maximal Heart Rate . 44 Submaximal Oxygen P u l s e 48 Maximal Oxygen P u l s e } 51 R e s u l t s and D i s c u s s i o n o f the S u b j e c t i v e Response Q u e s t i o n a i r e . . . . . . . . . 53 General D i s c u s s i o n . . . . 55 D i s c u s s i o n o f R e l a t e d L i t e r a t u r e 56 A p p l i c a t i o n o f the R e s u l t s . . . . . 58 L i m i t a t i o n s o f the D y n a v i t Ergometer 58 V SUMMARY AND CONCLUSIONS . 60 Summary 60 C o n c l u s i o n s 61 Recommendations 61 REFERENCES 62 APPENDICES . 6 9 Appendix A - S u b j e c t i v e Response Q u e s t i o n a i r e . . . . 70 Appendix B - Raw Data 72 Appendix C - ANOVA T a b l e s f o r Maximal Data 78 v i LIST OF TABLES T a b l e Page 1 C a l c u l a t i o n o f P e d a l l i n g Frequency and F r i c t i o n F a c t o r C o r r e c t i o n s . . . . . . 23 2 Order o f T e s t s f o r S u b j e c t s . 25 (Repeated L a t i n Square Design) 3 Age, H e i g h t , Weight, P e r c e n t Body Fat and Leg Length o f a l l S u b j e c t s ( P l u s Group Means and Sta n d a r d D e v i a t i o n s ) . . . . 30 4 T o t a l Work Time (Decimal M i n u t e s ) 31 (Means, St a n d a r d D e v i a t i o n s and F V a l u e s ) 5 T o t a l Work Time (Treatment Means i n Order) 33 6 Peak Oxygen Consumption (ml/kg/min) 36 (Means, Standard D e v i a t i o n s and F V a l u e s ) 7 Peak Oxygen Consumption (Treatment Means i n Order) . . . . 36 8 Submaximal Oxygen Uptake (ml/kg/min) . . . . 38 (Means and Standard D e v i a t i o n s ) 9 ANOVA T a b l e f o r Submaximal Oxygen Uptake 40 10 Submaximal Heart Rate (bpm) 41 (Means and Sta n d a r d D e v i a t i o n s ) 11 ANOVA T a b l e f o r Submaximal Heart Rate 43 12 Maximal Heart Rate (bpm) . . . . 46 (Means, St a n d a r d D e v i a t i o n s and F V a l u e s ) 13 Maximal Heart Rate (Treatment Means i n Order) 46 14 Submaximal Oxygen P u l s e (ml/beat) . 48 (Means and Standard D e v i a t i o n s ) 15 ANOVA T a b l e f o r Submaximal Oxygen P u l s e 50 16 Maximal Oxygen P u l s e (ml/beat) . 51 (Means, St a n d a r d D e v i a t i o n s and F V a l u e s ) 17 S u b j e c t i v e Response Q u e s t i o n a i r e 54 D i s t r i b u t i o n o f Responses: Reasons f o r D i s c o n t i n u i n g the T e s t s v i i LIST OF FIGURES F i g u r e * Page 1 Power Output ( F o r c e A p p l i c a t i o n C u r v e s ) f o r One Pedal R e v o l u t i o n a t Four D i f f e r e n t Ergometer Workload S e t t i n g s . . 13 2 Crank F o r c e Curve o f a S u b j e c t P u l l i n g a t h i s P e d a l s i n 16 the Upward P a r t o f the Foot C y c l e . . . . 3 D y n a v i t F u n c t i o n a l B l o c k Diagram . . . 18 4 E x p e r i m e n t a l D e s i g n : Hypotheses 1 , 2 , 3 and 4 28 5 E x p e r i m e n t a l D e s i g n : Hypotheses 5 and 6 28 6 T o t a l Work Time (Means and S t a n d a r d D e v i a t i o n s ) 32 7 Peak Oxygen Consumption (Means and S t a n d a r d D e v i a t i o n s ) . . . 35 8 Submaximal Oxygen Uptake (Means and Standard D e v i a t i o n s ) . . 39 9 Submaximal Heart Rate (Means and S t a n d a r d D e v i a t i o n s ) . . . 42 10 Maximal Heart Rate (Means and S t a n d a r d D e v i a t i o n s ) . . . . 45 11 Submaximal Oxygen P u l s e (Means and Standard D e v i a t i o n s ) . . . 49 12 Maximal Oxygen P u l s e (Means and Standard D e v i a t i o n s ) . . . . 52 v i i i ACKNOWLEDGEMENTS The a u t h o r wishes t o thank t he members o f h i s t h e s i s committee; Dr. S.R. Brown (Committee Chairman), Dr. E. Rhodes, Dr. K. C o u t t s , and Dr. H. V e n a b l e s . I would e s p e c i a l l y l i k e t o thank Dr. Brown f o r h i s v a l u a b l e t e c h n i c a l a s s i s t a n c e i n the w r i t i n g o f the f i n a l d r a f t . I would a l s o l i k e t o thank my c o l l e a g u e s who gave t h e i r f r e e time t o a s s i s t me d u r i n g t he many hours o f t e s t i n g , and e s p e c i a l l y my w i f e Lynne f o r her c o n t i n u o u s s u p p o r t and a s s i s t a n c e t h r o u g h o u t t he d u r a t i o n o f t h e s t u d y . And f i n a l l y , my thanks a r e extended t o the many s u b j e c t s who gave t h e i r b e s t e f f o r t on my b e h a l f . CHAPTER 1 STATEMENT OF THE PROBLEM I n t r o d u c t i o n The b e s t known method o f a s s e s s i n g a e r o b i c work c a p a c i t y i n man i s the measurement o f maximal oxygen uptake. The a b i l i t y t o p e r f o r m p r o l o n g e d , heavy, p h y s i c a l e x e r c i s e i s r e l a t e d t o the maximal c a p a c i t y o f the c a r d i o -r e s p i r a t o r y system t o d e l i v e r oxygen t o the working t i s s u e s , and d e t e r m i n a t i o n o f t h i s a e r o b i c c a p a c i t y r e q u i r e s a maximal o r near maximal e f f o r t o v e r a r e l a t i v e l y s h o r t p e r i o d o f time. Two o f t h e most commonly used p i e c e s o f equipment f o r the d e t e r m i n a t i o n o f maximal oxygen uptake, o r perhaps more c o r r e c t l y "peak oxygen consumption" (*16,47), a r e the m o t o r - d r i v e n t r e a d m i l l and t h e s t a t i o n a r y b i c y c l e ergometer. Many r e s e a r c h e r s have r e p o r t e d t h a t the maximal oxygen uptake s c o r e s a c h i e v e d d u r i n g t r e a d m i l l e x e r c i s e show c o n s i s t e n t l y h i g h e r v a l u e s than t h o s e determined on the b i c y c l e ergometer (8,9,16,18,20,27,32,38,39,45,48,52,55, 57,61,62,67,71,74,77). D i f f e r i n g v i e w p o i n t s have l o n g e x i s t e d as t o whether p e r i p h e r a l f a c t o r s such as v a s c u l a r conductance and muscle mass m e t a b o l i s m , o r c e n t r a l f a c t o r s such as c a r d i a c o u t p u t and b l o o d volume a r e the major l i m i t a t i o n s i n the d e t e r m i n a t i o n o f peak oxygen consumption d u r i n g maximal b i c y c l e ergometry ( 3 3 ) . Recent r e s e a r c h s u g g e s t s t h a t the amount o f muscle mass and t h e n a t u r e o f peak f o r c e a p p l i c a t i o n may be most im p o r t a n t (25,33, 39,41,52,65,66,67). O b t a i n i n g an a c c u r a t e maximal oxygen uptake v a l u e r e q u i r e s t h e c o o p e r a t i o n o f the s u b j e c t , who s h o u l d attempt a maximal e f f o r t d u r i n g the assessment. T h i s e f f o r t may be reduced by t h e i n a b i l i t y o r u n w i l l i n g n e s s o f the s u b j e c t t o endure g r e a t p h y s i c a l d i s c o m f o r t , whether the t e s t i s 1 2 b e i n g conducted on a t r e a d m i l l o r on a b i c y c l e . The most p r e v a l e n t c o m p l a i n t i n c o n v e n t i o n a l maximal b i c y c l e ergometry appears t o be l o c a l i z e d l e g muscle f a t i g u e e s p e c i a l l y a t h i g h w o r k l o a d s , r e s u l t i n g i n extreme l e g p a i n , l o s s o f a p p r o p r i a t e p e d a l i n g cadence and premature c e s s a t i o n o f e x e r c i s e b e f o r e the c a r d i o - r e s p i r a t o r y system becomes f u l l y t a x e d (8,9,12,17,32,38,39,45,46,47,52,56,60,63,69). The f a c t t h a t b i c y c l i n g i s a l e s s f a m i l i a r form o f e x e r c i s e t o the North American p o p u l a t i o n than w a l k i n g or r u n n i n g may be one p o s s i b l e cause o f premature f a t i g u e o f the l e g s d u r i n g c y c l i n g . But, the n a t u r e o f the l o a d i n g system o f the m e c h a n i c a l l y braked b i c y c l e ergometer may be a n o t h e r f a c t o r . S u b j e c t s u s i n g the new, e l e c t r o n i c a l l y l o a d e d , D y n a v i t b i c y c l e ergometer have r e p o r t e d t h a t t h e D y n a v i t i s p e d a l e d more e a s i l y and the workloads a r e a t t a i n e d w i t h l e s s s t r a i n and f a t i g u e when compared w i t h o t h e r t y p e s o f s t a t i o n a r y b i c y c l e ergometer. Less l e g muscle d i s c o m f o r t has a l s o been noted ( 2 4 ) . D y n a v i t o f America has s u g g e s t e d t h a t i n h e r e n t d e s i g n f e a t u r e s o f the D y n a v i t l o a d i n g ( o r b r a k i n g ) system do indeed r e s u l t i n s i g n i f i c a n t l y smoother f o r c e a p p l i c a t i o n and thus reduced l e g muscle f a t i g u e (24,64). "The l o a d i n g o f t h e f l y w h e e l , which a l l o w s f o r a more even t r a n s i t i o n d u r i n g p e r i o d s o f low f o r c e a p p l i c a t i o n t o p e r i o d s r e q u i r i n g h i g h e r t o r q u e s " ( 2 4 ) , has been compared t o an e l l i p t i c a l f o r c e a p p l i c a t i o n system such as t h a t put f o r w a r d by Henderson e t a l (37). The s u g g e s t i o n i s t h a t an e l l i p t i c a l f o r c e a p p l i c a t i o n system c o u l d b e t t e r match t h e t o r q u e o u t p u t c a p a b i l i t i e s o f the c y c l i s t t o the t o r q u e i n p u t r e q u i r e m e n t s o f the b i c y c l e than c o u l d a c i r c u l a r system (19,21,36,37). To t h e b e s t knowledge o f t h e a u t h o r , no c o n s i s t e n t r e s e a r c h has compared d i f f e r e n t t y p e s o f b i c y c l e ergometers ( i e : e l e c t r o n i c v e r s u s m e c h a n i c a l ) as t o the i n h e r e n t n a t u r e o f t h e i r l o a d i n g systems ( 2 4 ) . 3 I t was h y p o t h e s i z e d t h a t a d i f f e r e n c e i n t h e n a t u r e o f t h e l o a d i n g systems o f the two t y p e s o f b i c y c l e ergometers would cause a d i f f e r e n c e i n p h y s i c a l e f f o r t , and thus r e s u l t i n d i f f e r e n t p h y s i o l o g i c a l r e s p o n s e s . The p r e s e n t s t u d y was d e s i g n e d t o examine s e l e c t e d p o t e n t i a l d i f f e r e n c e s i n p h y s i o -l o g i c a l response t o maximal e x e r c i s e s t r e s s , between the e l e c t r o n i c a l l y braked, D y n a v i t b i c y c l e ergometer and the m e c h a n i c a l l y braked, Monark b i c y c l e ergometer. S e l e c t e d submaximal parameters were a l s o examined f o r s i g n i f i c a n t d i f f e r e n c e s , a l t h o u g h t h i s l a t t e r d a t a must be viewed w i t h a p p r o p r i a t e r e s e r v a t i o n due t o the l i m i t a t i o n s o f t h e c a l i b r a t i o n p r o c e s s i n h e r e n t t o the p r e s e n t s t u d y (see Assumptions and L i m i t a t i o n s ) . The Problem The p r i m a r y purpose o f t h i s i n v e s t i g a t i o n was t o compare two d i f f e r e n t t y p e s o f b i c y c l e ergometer i n t h e i r d e t e r m i n a t i o n o f peak oxygen consumption, as r e l a t e d t o t r e a d m i l l s c o r e s . The i n c l u s i o n o f t r e a d m i l l v a l u e s a f f o r d e d a c r i t e r i o n measure o f peak oxygen consumption, t o r e l a t e t o comparable v a l u e s a c h i e v e d on each b i c y c l e ergometer. Thus a means was p r o v i d e d t o examine which t y p e o f b i c y c l e ( e l e c t r o n i c o r m e c h a n i c a l ) c o u l d a c h i e v e peak oxygen consumption v a l u e s c l o s e t o o r as h i g h as the c r i t e r i o n v a l u e s a t t a i n e d on the t r e a d m i l l . T o t a l work time between the two b i c y c l e s was a l s o examined, on the premise t h a t the l o n g e r a s u b j e c t was a b l e t o c o n t i n u e e x e r c i s e , the g r e a t e r would be the l e v e l o f p h y s i c a l e x e r t i o n and thus the g r e a t e r the p h y s i o l o g i c a l r e s p o n s e . W i t h i n t h i s c o n t e x t , an e l e c t r o n i c a l l y braked, D y n a v i t b i c y c l e ergometer was compared t o a m e c h a n i c a l l y braked, Monark b i c y c l e ergometer, t o examine p o t e n t i a l d i f f e r e n c e s which may have been e l i c i t e d by t h e l o a d i n g systems unique t o each p i e c e o f equipment. 4 Sub-Problems 1) The oxygen uptake v a l u e s f o r s u c c e s s i v e submaximal workload i n t e r v a l s were compared f o r s i g n i f i c a n t d i f f e r e n c e s between t h e two b i c y c l e ergometers. 2) The h e a r t r a t e r e s p o n s e s f o r s u c c e s s i v e submaximal workload i n t e r v a l s were compared f o r s i g n i f i c a n t d i f f e r e n c e s between the two b i c y c l e ergometers. Hypotheses The f o l l o w i n g hypotheses were i n v e s t i g a t e d : 1) T o t a l , work time on the D y n a v i t b i c y c l e ergometer w i l l be s i g n i f i c a n t l y g r e a t e r than on the Monark b i c y c l e ergometer. 2) The D y n a v i t peak oxygen consumption v a l u e s w i l l be s i g n i f i c a n t l y g r e a t e r than the c o r r e s p o n d i n g Monark v a l u e s . 3) The t r e a d m i l l peak oxygen consumption v a l u e s w i l l be s i g n i f i c a n t l y g r e a t e r than c o r r e s p o n d i n g Monark v a l u e s . 4) T r e a d m i l l peak oxygen consumption v a l u e s w i l l not d i f f e r s i g n i f i c a n t -l y from comparable D y n a v i t v a l u e s . 5) D y n a v i t oxygen uptake v a l u e s a t submaximal workload i n t e r v a l s w i l l be s i g n i f i c a n t l y lower than c o r r e s p o n d i n g Monark v a l u e s . 6) D y n a v i t h e a r t r a t e r e s p o n s e s a t submaximal workload i n t e r v a l s w i l l be s i g n i f i c a n t l y l e s s than c o r r e s p o n d i n g Monark v a l u e s . Importance o f the Study The p r e s e n t study c o u l d p r o v i d e f u r t h e r i n f o r m a t i o n w i t h r e g a r d t o d i f f e r e n c e s i n peak oxygen consumption ( o r maximal oxygen uptake) between t r e a d m i l l and m e c h a n i c a l l y braked b i c y c l e ergometers. 5 The main purpose o f the s t u d y i s t o d e t e r m i n e i f the e l e c t r o n i c a l l y b r aked, D y n a v i t b i c y c l e ergometer can e l i c i t h i g h e r peak oxygen consumption v a l u e s than a m e c h a n i c a l l y b r a k e d , Monark b i c y c l e ergometer, and s i m i l a r t o t h o s e o f the t r e a d m i l l . I f t h e s e hypotheses are c o r r e c t , the i m p l i c a t i o n s f o r c l i n i c a l and e x p e r i m e n t a l t e s t i n g become c l e a r . The D y n a v i t b i c y c l e ergometer would p r o v i d e a r e l a t i v e l y i n e x p e n s i v e , p o r t a b l e , and a c c u r a t e t o o l f o r d e t e r m i n a t i o n o f peak oxygen consumption. E x p e r i m e n t a l f i n d i n g s o f submaximal v a l u e s o f h e a r t r a t e and oxygen uptake might have i m p l i c a t i o n s f o r submaximal t e s t i n g . I f t h e D y n a v i t b i c y c l e ergometer e l i c i t s s i g n i f i c a n t l y lower e x e r c i s e h e a r t r a t e and oxygen uptake r e s p o n s e s than a Monark ergometer, a t submaximal workload i n t e r v a l s , then the D y n a v i t may prove t o be a more s o p h i s t i c a t e d t o o l f o r submaximal e x e r c i s e e s t i m a t i o n o f c a r d i o - r e s p i r a t o r y endurance and peak oxygen consumption. T h i s would a l s o mean t h a t use o f t h e D y n a v i t f o r e s t i m a t i o n o f p h y s i c a l work c a p a c i t y ( M o d i f i e d S j o s t r a n d PWC T e s t ) o r p r e d i c t e d maximal oxygen uptake (Astrand-Ryhming P r e d i c t e d Oxygen Uptake T e s t ) u s i n g t h e c o r r e s p o n d i n g norms would be i n v a l i d . I f the D y n a v i t i s indeed d i f f e r e n t from the Monark i n i t s l o a d i n g m e c h a n i c s , d i f f e r e n t b i o -m e c h a n i c a l p r o p e r t i e s would be i n v o l v e d , t h u s r e q u i r i n g new o r r e v i s e d n o r m a t i v e s t a n d a r d s t o be d e v e l o p e d i f the p r e c e e d i n g t e s t s a r e t o be performed on the D y n a v i t ergometer. Assumptions and L i m i t a t i o n s 1) I t was assumed t h a t d i f f e r e n c e s i n t o t a l work t i m e , peak oxygen consumption, and t o a l e s s e r e x t e n t submaximal h e a r t r a t e and oxygen uptake r e s p o n s e s would r e f l e c t d i f f e r e n c e s i n the l o a d i n g mechanisms o f the two : b i c y c l e e rgometers. 6 2) I t was assumed t h a t an i n c r e a s e i n t o t a l work time d u r i n g maximal e x e r c i s e (independent o f l e a r n i n g e f f e c t s ) would r e s u l t i n a g r e a t e r t a x i n g o f the c a r d i o - r e s p i r a t o r y system and t h e r e f o r e a h i g h e r peak oxygen consumption v a l u e . 3) I t was assumed t h a t f a c t o r y c a l i b r a t i o n o f the D y n a v i t ergometer was as a c c u r a t e as c l a i m e d by t h e company, and d i d not change o v e r the d u r a t i o n o f the study. 4) The s t a n d a r d c a l i b r a t i o n t e c h n i q u e f o r the Momark ergometer was assumed t o produce a c c u r a t e workload s e t t i n g s (4,18). A c o r r e c t i o n f a c t o r f o r f r i c t i o n l o s s e s was a p p l i e d t o the s i n u s b a l a n c e a c c o r d i n g t o A s t r a n d ( 7 ) . 5) I t was assumed t h a t c h o o s i n g c o l l e g e - a g e d , n o n - t r a i n e d males as s u b j e c t s would reduce e x e r c i s e r e l a t e d r i s k f a c t o r s . T h i s p o p u l a t i o n was a l s o chosen so as t o reduce the p r o b a b i l i t y o f t e s t i n g a p p a r a t u s b i a s . That i s , h i g h l y t r a i n e d r u n n e r s and c y c l i s t s were e x c l u d e d from t h e s t u d y t o a v o i d b i a s towards e i t h e r t h e t r e a d m i l l run o r the b i c y c l e ergometer t e s t . 6) The s t u d y was l i m i t e d i n t h a t f r i c t i o n l o s s e s i n t h e c h a i n s and b e a r i n g s c o u l d not be d i r e c t l y d e t ermined f o r the two b i c y c l e ergometers. However, t h e D y n a v i t ergometer c a l i b r a t i o n p r o c e s s t a k e s f r i c t i o n l o s s e s i n t o a c c o u n t (53,64). And as p r e v i o u s l y mentioned, a c o r r e c t i o n f a c t o r f o r f r i c t i o n 'losses was a p p l i e d t o the s i n u s b a l a n c e o f the Monark ergometer. Del i m i t a t i o n s 1) T h i r t e e n n o n - t r a i n e d , c o l l e g e - a g e d male v o l u n t e e r s were used i n the i n v e s t i g a t i o n . 2) The age o f the s u b j e c t s ranged from 18-26 y e a r s . 3) The p h y s i c a l and p h y s i o l o g i c a l parameters d i s c u s s e d i n d e t a i l i n 7 Chapter 4 were r e s t r i c t e d t o t h o s e d e s c r i b e d i n the Problem and Sub-Problems s e c t i o n s o f t h i s c h a p t e r . D e f i n i t i o n s Maximal Oxygen Uptake: The h i g h e s t oxygen uptake t he i n d i v i d u a l can a t t a i n d u r i n g p h y s i c a l work w h i l e b r e a t h i n g a i r a t sea l e v e l ( 8 ) . Peak Oxygen Consumption: The h i g h e s t oxygen uptake v a l u e r e c o r d e d (mT/kg/mih) d u r i n g a c o n t i n u o u s maximal b i c y c l e ergometer t e s t (16,47). T h i s term was used i n p l a c e o f maximal oxygen uptake w i t h i n the c o n t e x t o f t h i s s t u d y , because Katch and Katch (47) sug g e s t e d t h a t a t r u e maximal oxygen uptake i s p r o b a b l y not a c h i e v e d (based on commonly a c c e p t e d c r i t e r i a ) d u r i n g a c o n t i n u o u s b i c y c l e ergometer t e s t , due t o l o c a l m u s c u l a r l i m i t a t i o n s . The c r i t e r i o n f o r the d e t e r m i n a t i o n o f peak oxygen consumption on a l l t h r e e p i e c e s o f equipment was the average o f t h e l a s t t h r e e 15 second v a l u e s o f oxygen uptake a t the same wor k l o a d , b e f o r e t h e c e s s a t i o n o f e x e r c i s e . T o t a l Work Time: T o t a l e l a p s e d time d u r i n g t he e x e r c i s e bout u n t i l t h e c e s s a t i o n o f the t e s t ( i n m i n u t e s ) . Submaximal Workload I n t e r v a l : Each t h r e e minute i n t e r v a l o f t h e t e s t where workload i s h e l d c o n s t a n t , and h e a r t r a t e i s l e s s than o r equal t o 170 bpm. Submaximal Heart Rate: Heart r a t e l e s s than o r equal t o 170 bpm, averaged o v e r t h e l a s t two 30 second d e t e r m i n a t i o n s a t t h e end o f each submaximal t h r e e minute workload i n t e r v a l (both r e a d i n g s t o be l e s s than o r equal t o 170 bpm). Submaximal Oxygen Uptake: The oxygen uptake v a l u e averaged o v e r t h e l a s t two 30 second d e t e r m i n a t i o n s a t the end o f each submaximal t h r e e minute workload i n t e r v a l ( b o t h c o r r e s p o n d i n g h e a r t r a t e r e a d i n g s t o be l e s s than o r equal t o 170 bpm). Non-Trained: Any c o l l e g e - a g e d male v o l u n t e e r not c u r r e n t l y o r r e c e n t l y i n v o l v e d i n a r e g u l a r t r a i n i n g program o f a t h l e t i c endeavor, as o u t l i n e d by the p o s i t i o n statement o f the American C o l l e g e o f S p o r t s M e d i c i n e ( 2 ) , and as d e t e r m i n e d by a p p r o p r i a t e q u e s t i o n a i r e . CHAPTER II REVIEW OF THE LITERATURE F a c t o r s R e l a t e d t o the D e t e r m i n a t i o n o f Maximal Oxygen Uptake E x t e n s i v e r e s e a r c h has been condu c t e d u s i n g both t h e t r e a d m i l l and the b i c y c l e ergometer i n the d e t e r m i n a t i o n o f maximal oxygen uptake. The m a j o r i t y . o f s t u d i e s r e v e a l t h a t the t r e a d m i l l e l i c i t s s i g n i f i c a n t l y h i g h e r maximal oxygen uptake v a l u e s than the s t a t i o n a r y b i c y c l e . The d i f f e r e n c e seems t o depend on s e v e r a l f a c t o r s . Most o f the r e s e a r c h e r s agree t h a t the amount o f muscle mass i n v o l v e d d u r i n g t r e a d m i l l r u n n i n g i s g r e a t e r than d u r i n g b i c y c l i n g (9,32,33), but the n a t u r e o f t h i s i n v o l v e m e n t i s not c l e a r l y u n d e r s t o o d . A s t r a n d (5,6) and l a t e r G l e s e r (33) s u p p o r t e d the i d e a t h a t p e r i p h e r a l f a c t o r s such as the s i z e o f the v a s c u l a r bed o f t h e e x e r c i s i n g muscle, and/or venous r e t u r n were the major l i m i t i n g f a c t o r s i n maximal b i c y c l e e x e r c i s e , r a t h e r than c e n t r a l f a c t o r s such as c a r d i a c o u t p u t o r b l o o d volume. Thus, because s t a t i o n a r y c y c l i n g i n v o l v e d a s m a l l e r muscle mass than r u n n i n g , lower v a s c u l a r conductance and/or venous r e t u r n l i m i t e d the amount and i n t e n s i t y o f work which c o u l d be t o l e r a t e d . The c o n c e p t o f r e l a t i n g oxygen uptake t o the volume o f p a r t i c i p a t i n g muscle mass i n maximal e x e r c i s e seems l o g i c a l , but t h e r e i s a c o n t r o v e r s y as t o whether an i n c r e a s e i n a c t i v e muscle mass i n b i c y c l i n g would r e s u l t i n an i n c r e a s e i n maximal oxygen uptake. A s t r a n d (5,6) a s s e r t e d i n i t i a l l y t h a t u s i n g arm p l u s l e g e x e r c i s e on the b i c y c l e ergometer r e s u l t e d i n a h i g h e r maximal oxygen uptake than l e g s a l o n e , but e v e n t u a l l y abandoned t h i s t h e o r y i n f a v o u r o f the c o n c e p t o f a c r i t i c a l mass. H i s 1961 s t u d y (9) i n d i c a t e d t h a t a d d i t i o n a l muscle mass in v o l v e m e n t p a s t a c e r t a i n c r i t i c a l mass d i d not i n c r e a s e maximal oxygen uptake f u r t h e r . He s t a t e d t h a t "the 9 10 c e i l i n g f o r oxygen uptake seems independent o f the mass o f muscle employed i n the e x e r c i s e as soon as i t exceeds a c e r t a i n mass." He then s u g g e s t e d c a r d i a c o u t p u t as the main l i m i t i n g f a c t o r i n maximal oxygen uptake d e t e r m i n a t i o n s on the b i c y c l e ergometer. But, s e v e r a l r e s e a r c h e r s s i n c e 1961 have tended t o s u p p o r t A s t r a n d ' s o r i g i n a l h y p o t h e s i s t h a t i n c r e a s i n g t h e p a r t i c i p a t i n g muscle mass r e s u l t s i n h i g h e r maximal oxygen uptake v a l u e s when e x e r c i s i n g on a b i c y c l e ergometer (33,52,67,75). However, s t u d i e s by S tenberg (72) and F a i r b a n k s (25) found no d i f f e r e n c e i n maximal oxygen uptake v a l u e s when arm p l u s l e g work was compared t o l e g work a l o n e d u r i n g c y c l i n g . When comparing t r e a d m i l l r u n n i n g w i t h s t a t i o n a r y c y c l i n g , c o n s i d e r a t i o n must be made o f p o s s i b l e d i f f e r e n c e s . i n the b i o m e c h a n i c a l p r o p e r t i e s o f the two t y p e s o f a c t i v i t y , and the c o n t r i b u t i o n o f t h e s e p r o p e r t i e s t o the o n s e t o f f a t i g u e i n maximal e x e r c i s e . "In c y c l i n g t h e c o n t r a c t i o n p o r t i o n o f t h e c o n t r a c t i o n - r e l a x a t i o n c y c l e i s q u i t e p r o l o n g e d and the peak l o a d s a r e a p p r o x i m a t e l y t w i c e the l o a d s e t t i n g . Running i s much more o f a b a l l i s t i c movement w i t h a v e r y s h o r t c o n t r a c t i o n phase. These b i o m e c h a n i c a l f a c t o r s would c o n t r i b u t e t o a g r e a t e r impairment i n s k e l e t a l muscle b l o o d f l o w c y c l i n g than r u n n i n g . " (27). A s t u d y by Gray (34) has shown t h a t a r e d u c t i o n i n venous r e t u r n may r e s u l t from t w i s t i n g , k i n k i n g o r l o c a l compression o f the b l o o d v e s s e l s as t h e y pass t h r o u g h a c o n t r a c t i n g muscle. Folkow and H a l i c k a (29) have o b s e r v e d impairment o f l o c a l b l o o d f l o w a t h i g h muscle f i b e r t w i t c h r a t e s ( i n s i t u muscle p r e p a r a t i o n s ) , and Matsui e t a l (55) and Miyamura (61) have r e p o r t e d g r e a t e r r e d u c t i o n o f b l o o d f l o w d u r i n g c y c l i n g than t r e a d m i l l r u n n i n g . These v a r i o u s r e p o r t s s t r o n g l y s u g g e s t t h a t the h i g h peak f o r c e a p p l i c a t i o n r e q u i r e d d u r i n g c y c l i n g , and the r e s u l t a n t l o c a l c ompression o f the 11 v a s c u l a r system by i n t e n s e m u s c u l a r c o n t r a c t i o n may cause reduced venous r e t u r n . I t f o l l o w s t h a t c a r d i a c o u t p u t w i l l f a l l , t hus l i m i t i n g the i n t e n s i t y and d u r a t i o n o f c y c l i n g e x e r c i s e when compared t o t r e a d m i l l r u n n i n g . I t i s w e l l known t h a t maximal oxygen uptake depends p r i m a r i l y on c a r d i a c o u t p u t and the a b i l i t y o f the working muscle t i s s u e s t o e x t r a c t oxygen (a-vC^ d i f f e r e n c e ) (27,59,61). Recent s t u d i e s i n d i c a t e t h a t c a r d i a c o u t p u t , a-vC^ d i f f e r e n c e and l e g muscle b l o o d f l o w may be g r e a t e r d u r i n g t r e a d m i l l r u n n i n g than b i c y c l e ergometer e x e r c i s e (38,60,61), due t o s e v e r a l p o s s i b l e c o n t r i b u t i n g f a c t o r s : 1) The l o w e r c a r d i a c o u t p u t may be due t o a lower maximal h e a r t r a t e i n c y c l i n g . 2) High i n t r a m u s c u l a r p r e s s u r e s e x e r t e d d u r i n g maximal c y c l i n g may l i m i t venous r e t u r n , thus r e d u c i n g c a r d i a c o u t p u t and l e g muscle b l o o d f l o w . 3) The lower a-v0£ d i f f e r e n c e may be due t o the lower working muscle mass d u r i n g c y c l i n g . T r o m the above r e v i e w o f r e l a t e d l i t e r a t u r e i t would appear t h a t p o s s i b l e b i o m e c h a n i c a l d i f f e r e n c e s between s t a t i o n a r y c y c l i n g and t r e a d m i l l r u n n i n g may be most c r u c i a l i n e x p l a i n i n g the a p p a r e n t s u p e r i o r i t y o f the t r e a d m i l l i n t h e d e t e r m i n a t i o n o f maximal oxygen uptake. The amount o f muscle mass, t h e n a t u r e o f f o r c e a p p l i c a t i o n and the c o n c o m i t a n t degree o f i n t r a m u s c u l a r c o n s t r i c t i o n may prove t o be most i m p o r t a n t i n d e t e r m i n i n g the v a r i o u s p h y s i o l o g i c a l r e s p o n s e s t o maximal c y c l i n g e x e r c i s e , when compared w i t h r u n n i n g . B i c y c l e Ergometry and Maximal E x e r c i s e The f i r s t e l e c t r i c a l l y braked b i c y c l e ergometer was d e v e l o p e d near 12 t h e b e g i n n i n g o f t h e c e n t u r y as an a l t e r n a t i v e t o m e c h a n i c a l l y braked b i c y c l e s , and p r o v i d e d a crude t o o l f o r a s s e s s i n g p h y s i c a l work c a p a c i t y . See C a r r o l l (15) f o r a complete r e v i e w o f l i t e r a t u r e . Subsequent r e f i n e m e n t s may p r o v i d e a more s o p h i s t i c a t e d means o f a s s e s s i n g maximal oxygen uptake (or peak oxygen consumption) than a m e c h a n i c a l l y braked b i c y c l e ergometer o r the e a r l y e l e c t r i c a l l y braked ergometers. Hoes e t a l (41) and S a r g e a n t (65,66) have demonstrated t h a t the peak power o u t p u t r e q u i r e d i n one pedal r e v o l u t i o n a t a g i v e n workload (on an e a r l y e l e c t r o - m a g n e t i c and a m e c h a n i c a l l y braked b i c y c l e ergometer r e s p e c t -i v e l y ) i s s i g n i f i c a n t l y g r e a t e r than t h a t o f the workload s e t t i n g . Hoes r e p o r t s a peak power o u t p u t t w i c e t h a t o f the workload s e t t i n g . F u r t h e r m o r e , t h i s peak power o u t p u t i s a p p l i e d over a r e l a t i v e l y small p o r t i o n o f the pedal r e v o l u t i o n . As workload i n c r e a s e s , the s l o p e o f the f o r c e a p p l i c a t i o n c u r v e becomes s t e e p e r , so t h a t a t maximal workloads an e x t r e m e l y h i g h power output i s r e q u i r e d o v e r a v e r y s h o r t a p p l i c a t i o n d i s t a n c e (41). See F i g u r e 1 f o r a d i a g r a m a t i c i l l u s t r a t i o n o f the above m a t e r i a l . When a h i g h e r t e n s i o n i s r e q u i r e d , t h i s can be a c h i e v e d by a c t i v a t i n g a l a r g e r number o f muscle f i b e r s and/or by i n c r e a s i n g the f r e q u e n c y o f s t i m u l a t i o n , depending on the f o r c e a p p l i c a t i o n d i s t a n c e (3,50). From the above st a t e m e n t s i t f o l l o w s t h a t l o c a l i z e d muscle f i b e r r e c r u i t m e n t o f a maximal n a t u r e may o c c u r , l e a d i n g t o premature and e x t r e m e l y l o c a l i z e d l e g muscle f a t i g u e ( 3 8 ) . C o n t r i b u t i n g t o the l o c a l i z e d f a t i g u e o f the l e g muscles i n maximal e x e r c i s e , e s p e c i a l l y the t e n s o r f a s c i a e l a t a e , s a r t o r i u s , q u a d r i c e p s f e m o r i s , v a s t u s l a t e r a l i s and t i b i a l i s a n t e r i o r (24,43), i s the p r e f e r e n t i a l o r d e r o f r e c r u i t m e n t o f the motor u n i t s and the t y p e s o f muscle f i b e r s i n v o l v e d . D u r i n g a c o n t i n u o u s , i n c r e m e n t a l maximal b i c y c l e ergometer t e s t , slow t w i t c h o x i d a t i v e (SO) and f a s t t w i t c h o x i d a t i v e g l y c o l y t i c (FOG) 13 to +-> (0 -t-> Q. +-> o CL) s o Q_ 800. 700 600 500 400 300 200 100 0 7 5 1" D .5 1 Time (seconds) 100 200 300 Ergometer Workload (Watts) 400 FIGURE 1 POWER OUTPUT (FORCE APPLICATION CURVES) FOR ONE PEDAL REVOLUTION AT FOUR DIFFERENT ERGOMETER WORKLOAD SETTINGS: 60 RPM (41) 14-f i b e r s a r e r e c r u i t e d i n i t i a l l y , w i t h more and more FOG and f a s t t w i t c h g l y c o l y t i c (FG) i n v o l v e m e n t as i n t e n s i t y i n c r e a s e s . The FG f i b e r s become q u i c k l y exhausted a t h i g h workloads (due t o the a s s o c i a t e d s t e e p f o r c e a p p l i c a t i o n c u r v e and the s h o r t term work c h a r a c t e r i s t i c s o f FG f i b e r s ) , thus t o o g r e a t a s t r e s s i s p l a c e d on t h e o x i d a t i v e f i b e r s r e s u l t i n g i n premature, l o c a l i z e d l e g muscle f a t i g u e b e f o r e t r u e c a r d i o - r e s p i r a t o r y e x h a u s t i o n i s a c h i e v e d . I f the power o u t p u t r e q u i r e d by the l e g muscles d u r i n g c y c l i n g can be more e v e n l y a p p l i e d , the r e s u l t s h o u l d be a more equal d i s t r i b u t i o n between the number and t y p e o f muscle f i b e r s r e c r u i t e d and t h e i r f r e q u e n c y o f s t i m u l a t i o n . Thus a more advantageous d i s t r i b u t i o n o f e f f o r t between slow . t w i t c h , f a s t t w i t c h o x i d a t i v e g l y c o l y t i c and f a s t t w i t c h g l y c o l y t i c f i b e r s may be a c h i e v e d , and a r e l a t i v e l y l a r g e r number o f t h e s e f i b e r s may be a c t i v a t e d a t a lower f i r i n g f r e q u e n c y t o do the same amount o f work (3,8, 50). The i m p l i c a t i o n s f o r maximal e x e r c i s e on the b i c y c l e ergometer s h o u l d be a g r e a t e r t o t a l work time and t h e r e f o r e a g r e a t e r t a x i n g o f the c a r d i o -r e s p i r a t o r y system. The work o f L a v o i e e t a l (52) p r o v i d e s i n d i r e c t s u p p o r t f o r the above c o n t e n t i o n . He found t h a t u s i n g r a c i n g s t i r r u p s on a f r i c t i o n braked b i c y c l e ergometer gave maximal oxygen uptake v a l u e s s i g n i f i c a n t l y h i g h e r than w i t h o u t s t i r r u p s , and not s i g n i f i c a n t l y d i f f e r e n t from t r e a d m i l l v a l u e s . H i s c o n t e n t i o n was t h a t the r a c i n g s t i r r u p s .enabled the s u b j e c t t o i n c r e a s e the amount o f a c t i v e muscle mass by b e i n g a b l e t o p u l l up w i t h one l e g w h i l e p u s h i n g down w i t h t h e o t h e r . However, i n Hoes s t u d y (41) i t appears t h a t the shape o f the f o r c e a p p l i c a t i o n c u r v e d i d not change s i g n i f i c a n t l y when s t i r r u p s were used, a l t h o u g h the n e g a t i v e drag component (due t o the l i f t i n g o f the p a s s i v e l e g by the a c t i v e l e g ) i s v i r t u a l l y 15 . e l i m i n a t e d . See F i g u r e 2 f o r a d i a g r a m a t i c i l l u s t r a t i o n o f the above m a t e r i a l . I t s h o u l d be noted t h a t the p r i m a r y s u b j e c t i n Hoes st u d y was a r a c i n g c y c l i s t who a d m i t t e d l y o n l y used h i s s t i r r u p s on h i l l s o r i n s p r i n t s . L a v o i e ' s s u b j e c t s used the s t i r r u p s a t a l l t i m e s , w h i l e Hoe's s u b j e c t d i d n o t , thus l i m i t i n g c o m p a r a t i v e c o n c l u s i o n s . I t may be t h a t t h e r a c i n g s t i r r u p s i n L a v o i e ' s s t u d y reduced the peak f o r c e r e q u i r e d d u r i n g each r e v o l u t i o n by r e d u c i n g t h e n e g a t i v e d r a g component, by more e v e n l y d i s t r i b u t i n g the r e q u i r e d f o r c e among a s l i g h t l y l a r g e r muscle mass and by a p p l y i n g the f o r c e o v e r a g r e a t e r d i s t a n c e ( i e : d u r i n g the upward l i f t i n g phase as w e l l as the downward p u s h i n g p h a s e ) . (46). D y n a v i t Versus Monark i n Maximal and Submaximal E x e r c i s e An e l e c t r o n i c b i c y c l e ergometer o r i g i n a l l y d e v e l o p e d i n West Germany, the D y n a v i t , i s p u r p o r t e d t o v i r t u a l l y " e l i m i n a t e premature l e g muscle f a t i g u e . " (30). The D y n a v i t i n c l u d e s an e l e c t r o n i c b r a k i n g system which i s computer c o n t r o l l e d . Thus a c o n s t a n t workload can be a c c u r a t e l y p r o v i d e d r e l a t i v e l y independent o f p e d a l l i n g speed ( p l u s o r minus 2% a t 45-60 rpm, minus 5-7% a t 85 rpm). (64). T h i s i s i n c l o s e agreement w i t h t h e c a l i b r a t i o n e r r o r o f o t h e r r e c e n t e l e c t r o n i c b i c y c l e ergometers (42,44). F r i c t i o n a l l o s s e s i n the b e a r i n g s , c h a i n , b e l t s , w i n d i n g s , e t c . , a r e a c c o u n t e d f o r i n the c a l i b r a t i o n p r o c e s s (18',53,64). "An u l t r a h i g h - s p e e d f l y w h e e l i s i n c l u d e d i n the b r a k i n g system, and becomes p a r t o f any g i v e n workload. The f l y w h e e l ' s mass (weight) a s s o c i a t e d w i t h a g e a r i n g r a t i o more than 35 times the p e d a l l i n g speed, k i n e t i c a l l y ' l o a d s ' the f l y w h e e l . " ( 3 0 ) . The s p e c i f i c amount o f energy s t o r e d i s a f u n c t i o n o f f l y w h e e l mass and r o t a t i o n a l v e l o c i t y (23). " T h i s r e s e r v e s u p p l y o f k i n e t i c energy w i t h i n the f l y w h e e l a s s i s t s i n the peak f o r c e r e q u i r e d and e q u a l i z e s the f o r c e needed f o r each 16 CO c O CU 375 250 125 125 S u b j e c t P u l l i n g Upward a t H i s P e d a l s — S u b j e c t Not P u l l i n g Upward a t H i s P e d a l s ---0° 90 180 270 360 Bottom Top Bottom FIGURE 2 CRANK FORCE CURVE OF A SUBJECT PULLING AT HIS PEDALS IN THE UPWARD PART OF THE FOOT CYCLE (0°T0 180° AT 300 WATTS AND 60 RPM) 17 r e v o l u t i o n . P e d a l l i n g the D y n a v i t i s not o n l y smooth but a l s o reduces o r e l i m i n a t e s the tendency f o r premature l e g muscle f a t i g u e . " ( 3 0 ) . See F i g u r e 3 f o r a d i a g r a m a t i c i l l u s t r a t i o n o f the f u n c t i o n a l l o a d i n g system o f the D y n a v i t ergometer. A c c o r d i n g to D y n a v i t o f America O p e r a t i o n s Manager L, Peck, the D y n a v i t l o a d i n g system r e s u l t s i n an e f f e c t s i m i l a r t o t h e use o f an e l l i p t i c a l element i n t h e b r a k i n g system, as o u t l i n e d i n t h e I n t r o d u c t i o n t o the Problem i n C h a p t e r 1. "With an e l l i p t i c a l chainwheel i t i s p o s s i b l e t o p o s i t i o n the p e d a l s so t h a t as each l e g e x e r t s i t s maximum f o r c e , the e l l i p s e a c t s as a l a r g e r c i r c u l a r chainwheel and a c c e l e r a t e s the c h a i n r a p i d l y t h r o u g h a s m a l l change i n crank a n g l e . Thus, as t h e p e d a l s are moved a g i v e n d i s t a n c e t h r o u g h the power t h r u s t more work c a n b e done w i t h an e l l i p t i c a l chainwheel than w i t h a c i r c u l a r s p r o c k e t o f e q u a l c i r c u m f e r e n c e . With t h e l e g s i n t h e l e a s t f a v o r a b l e p o s i t i o n f o r t o r q u e o u t p u t , t h e e l l i p s e a c t s as a small c i r c u l a r chainwheel which r e q u i r e s l e s s f o r c e t o move the p e d a l s t h r o u g h the r e q u i r e d crank a n g l e . The e l l i p s e t h e n , e x t r a c t s a g r e a t e r p e r c e n t a g e o f work o u t p u t from the c y c l i s t when h i s Tegs are a t the o p t i m a l crank a n g l e t o do work. T h i s c o u l d r e s u l t i n a lower energy e x p e n d i t u r e w h i l e p e r f o r m i n g a g i v e n amount o f e x t e r n a l work." ( 3 7 ) . The e f f e c t s u g g e s t e d i s a more smooth a p p l i c a t i o n o f f o r c e t h r o u g h o u t the e n t i r e pedal r e v o l u t i o n (19,21,36,37). An u n p u b l i s h e d s t u d y by E d i n g t o n (24) s u p p o r t s t h e p r e v i o u s s t a t e m e n t s . H i s d e t a i l e d f i n d i n g s s u g g e s t ' l e s s p e r c e i v e d e x e r t i o n , lower peak EMG a c t i v i t y i n the v a s t u s l a t e r a l i s , l e s s peak f o r c e r e q u i r e d d u r i n g p e d a l l i n g , more c o n s t a n t pedal excursion-, l e s s d e c r e a s e i n g l y c o g e n c o n c e n t r a t i o n , lower oxygen r e q u i r e m e n t , lower e x e r c i s e h e a r t r a t e and l e s s peak a c c e l e r a t i o n a t the h i p when' r i d i n g the D y n a v i t , as compared t o a Monark ergometer. T h i s s t u d y was c o n d u c t e d a t a c o n s t a n t w o r k l o a d o f 900 kpm Pedal Chain D r i v e Gear R a t i o 1:35.17 Ear F i n g e r C I i p / Flywhee and Fan P r e - A m p l i f i e r \ P u l s e A m p ! i f i e r Whisper D r i v e Rib B e l t s E l e c t r o n i c V a r i a b l e Load D i g i t a l Symbolic D i s p l a y m ZD CD i—i CD o o < o >-19 (Monark) o r 150 watts ( D y n a v i t ) i n 40 t o -55 y e a r o l d men o f v a r i e d f i t n e s s l e v e l s . There i s however, some q u e s t i o n as t o whether the workloads were c o m p l e t e l y equated between the two er g o m e t e r s , as no mention i s made o f a c o r r e c t i o n f a c t o r f o r f r i c t i o n l o s s e s i n the Monark c a l i b r a t i o n p r o c e s s , as o u t l i n e d and d e c l a r e d n e c e s s a r y by Cumming (18) and A s t r a n d ( 7 ) . Nor i s i t c o m p l e t e l y c l e a r whether the p e d a l l i n g f r e q u e n c y was 50 o r 60 rpm, o r whether both ergometers were m a i n t a i n e d a t t h e same p e d a l l i n g speed. These l a t t e r two f a c t o r s are c r i t i c a l i n t h a t i f the p e d a l l i n g speed i s 60 rpm, then a c o r r e c t i o n f a c t o r must be a p p l i e d t o the Monark t o equate i t s work-l o a d s e t t i n g t o the D y n a v i t s e t t i n g ' o f 150 wa t t s ( i e : a 3 kp s e t t i n g a t 50 rpm i s equal t o 6 meters times 50 rpm times 3 kp, which e q u a l s 900 kpm/min. T h i s s e t t i n g i s equal t o 150 w a t t s . But, a t 60 rpm a 3 kp s e t t i n g i s e qual t o 6 meters times 60 rpm times 3 kp, which e q u a l s 1080 kpm/min on t h e Monark. T h i s f i g u r e i s no l o n g e r equal t o the D y n a v i t s e t t i n g o f 150 w a t t s , because the D y n a v i t m a i n t a i n s a c o n s t a n t w o r k l o a d independent o f p e d a l l i n g speed, w h i l e the Monark o b v i o u s l y does n o t ) . S e c o n d l y , i f the two ergometers were not o p e r a t i n g a t the same p e d a l l i n g f r e q u e n c y , then d i f f e r e n t b i o m e c h a n i c a l f a c t o r s may have been i n v o l v e d i n d e t e r m i n i n g the v a r i o u s p h y s i o l o g i c a l r e s p o n s e s t o e x e r c i s e between the two b i c y c l e ergometers (27,39,61). • The m e c h a n i c a l l y b r a k e d , Monark ergometer a c h i e v e s i t s b r a k i n g f o r c e v i a a f r i c t i o n b e l t around the r i m o f the f l y w h e e l ( 7 , 7 6 ) . To m a i n t a i n a c o n s t a n t workload a s t e a d y p e d a l l i n g f r e q u e n c y must be e n s u r e d by the use o f a metronome, which i n i t s e l f may i n t r o d u c e a work measurement e r r o r o f 10% (.18). A l s o c o n t r i b u t i n g t o measurement e r r o r a r e the f r i c t i o n a l l o s s e s i n the c h a i n and b e a r i n g s , which as mentioned e a r l i e r a r e not take n i n t o a c c o u n t d u r i n g s t a n d a r d c a l i b r a t i o n . T h i s may c o n t r i b u t e an i n c r e a s e d 20 r e s i s t a n c e o f a p p r o x i m a t e l y 9%, i f not c o r r e c t e d ( 7 , 1 8 ) , As p r e v i o u s l y mentioned, the peak-power o u t p u t r e q u i r e d d u r i n g one pedal: r e v o l u t i o n on a m e c h a n i c a l l y braked b i c y c l e ergometer (and e a r l y e l e c t r o - m a g n e t i c ergometers) i s much g r e a t e r than the wo r k l o a d s e t t i n g , a p p l i e d o v e r a v e r y s m a l l a n g l e o f r o t a t i o n . Thus the f o r c e a p p l i c a t i o n c u r v e cannot be c o n s i d e r e d t o be smooth and e v e n l y d i s t r i b u t e d on a m e c h a n i c a l l y braked b i c y c l e ergometer such as the Monark. The preponderance o f the l i t e r a t u r e which has been d i s c u s s e d tends t o s u p p o r t t he c l a i m s made by D y n a v i t o f America t h a t t he b r a k i n g o r l o a d i n g system o f the D y n a v i t ergometer may g r e a t l y reduce premature l e g muscle f a t i g u e . The i m p l i c a t i o n s f o r maximal c y c l i n g may be t h a t "improvement" i n the mechanical p r o p e r t i e s o f the D y n a v i t c o u l d r e s u l t i n improved l e g muscle f u n c t i o n i n maximal e x e r c i s e , as a r e s u l t o f the o p e r a t i o n o f one o r more f a c t o r s . Some o f thes e a r e s u g g e s t e d by t h e - l i t e r a t u r e , j * e : (a) a r e d u c t i o n i n venous r e t u r n ( 3 4 ) , (b) an impairment i n l o c a l b l o o d f l o w ( 2 9 ) , both d e s c r i b e d on' page 10, and o t h e r s about which i t i s o n l y p o s s i b l e t o s p e c u l a t e ( t h e e f f e c t o f f o r c e o f muscle c o n t r a c t i o n on the nervous system and the m e d i a t i n g e f f e c t s o f t h i s o n c e n t r a l nervous system f a t i g u e , s t i m u l u s t o t he h e a r t , and p r e s s o r mechanisms). The p r e s e n t s t u d y attempted t o examine p o t e n t i a l d i f f e r e n c e s i n the b r a k i n g systems o f the Monark and D y n a v i t b i c y c l e e rgometers. D i r e c t e x a m i n a t i o n o f peak f o r c e a p p l i c a t i o n (as c a r r i e d out by E d i n g t o n ) was beyond t h e scope o f t h i s s t u d y , but s e v e r a l p h y s i o -l o g i c a l v a r i a b l e s were compared i n an attempt t o i n f e r d i f f e r e n c e s i n the b r a k i n g systems unique t o each a p p a r a t u s . CHAPTER I I I METHODS AND PROCEDURES S u b j e c t s T h i r t e e n h e a l t h y , n o n - t r a i n e d , male s u b j e c t s aged from 18-26 y e a r s p a r t i c i p a t e d i n t h i s s t u d y , a l l b e i n g v o l u n t e e r s . A c t i v i t y l e v e l was determined by an a p p r o p r i a t e q u e s t i o n a i r e d e v e l o p e d from the American C o l l e g e o f S p o r t s M e d i c i n e p o s i t i o n statement on the q u a n t i t y and q u a l i t y o f e x e r c i s e ( 2 ) . A l l s u b j e c t s but two were t e s t e d a t the same time o f day f o r a l l t r e a t m e n t s , and a minimum o f t h r e e days was a l l o w e d between t e s t i n g s e s s i o n s t o ensure complete r e c o v e r y . The two s u b j e c t s who were not t e s t e d a t the same time o f day were unable t o do so because o f p e r s o n a l time c o n s t r a i n t s and/or the c o n s t r a i n t s o f the t e s t i n g p e r i o d i t s e l f . A l t h o u g h 12 s u b j e c t s were t o be used i n the s t u d y o r i g i n a l l y , t he c o n s t r a i n t s o f a p p a r a t u s a v a i l a b i l i t y made i t n e c e s s a r y t o t e s t e x t r a p a r t i c i p a n t s t o a l l o w f o r p o s s i b l e a t t r i t i o n . A l l s u b j e c t s were r e l a t i v e l y l e a n ( l e s s than 15% body f a t ) . Apparatus A new m e c h a n i c a l l y b r a k e d , Monark b i c y c l e ergometer was used i n the s t u d y , c a l i b r a t e d b e f o r e and a t r e g u l a r i n t e r v a l s t h r o u g h o u t the s t u d y , i n a c c o r d a n c e w i t h p u b l i s h e d i n s t r u c t i o n s ( 7 ) . The t e s t - r e t e s t r e l i a b i l i t y c o e f f i c i e n t f o r maximal oxygen uptake t e s t s u s i n g the Monark ergometer i s r=.95 (56). A c o r r e c t i o n f a c t o r was a p p l i e d t o the s i n u s b a l a n c e o f the Monark t o equate the workloads between the two t y p e s o f b i c y c l e ergometers. T h i s was n e c e s s a r y because the p e d a l l i n g f r e q u e n c y was s e t a t 60 rpm. A l s o i n c l u d e d i n t h i s c o r r e c t i o n f a c t o r was an adjustment f o r f r i c t i o n l o s s e s i n the Monark c h a i n and b e a r i n g s , a f a c t o r which i s not t a k e n i n t o a c c o u n t 21 22 d u r i n g s t a n d a r d c a l i b r a t i o n (4,7,18). See T a b l e 1 f o r t h e c a l c u l a t i o n o f the p e d a l l i n g f r e q u e n c y and f r i c t i o n f a c t o r c o r r e c t i o n s , and the r e s u l t a n t workload s e t t i n g s . The D y n a v i t b i c y c l e ergometer employed i n the s t u d y was a new, f a c t o r y c a l i b r a t e d , e l e c t r o n i c a l l y braked one. The t e s t - r e t e s t r e l i a b i l i t y c o e f f i c i e n t f o r p r e d i c t i o n o f maximal oxygen uptake from submaximal work on the D y n a v i t ranges from r=.904 t o .988. No known dat a i s a v a i l a b l e f o r t h e t e s t - r e t e s t r e l i a b i l i t y o f t h e D y n a v i t i n t h e d e t e r m i n a t i o n o f maximal oxygen uptake. Because o f the g r e a t expense, time i n v o l v e m e n t and c o m p l i c a t i o n s o f b u i l d i n g a p p r o p r i a t e c a l i b r a t i o n equipment i t was not p o s s i b l e t o c a l i b r a t e the ergometer on s i t e , and the assumption was made t h a t s t a n d a r d f a c t o r y c a l i b r a t i o n o f the D y n a v i t was as a c c u r a t e as c l a i m e d , and d i d not change o v e r t h e d u r a t i o n o f the study. D y n a v i t o f America O p e r a t i o n s Manager L. Peck s t a t e s t h a t the c a l i b r a t i o n e r r o r i s p l u s or minus 2% a t 45-60 rpm, and t h a t as rpm i n c r e a s e s the l o a d t o l e r a n c e i n c r e a s e s i n a n e g a t i v e f a s h i o n . Thus, a t 85 rpm t h e e r r o r o f the workload s e t t i n g i s a p p r o x i m a t e l y -5 t o -7%. As the p r e s e n t s t u d y was p r i m a r i l y concerned w i t h maximal e x e r c i s e , t h i s l i m i t a t i o n i n t h e c a l i b r a t i o n o f t h e D y n a v i t i s not o f g r e a t s i g n i f i c a n c e , except' i n e x a m i n a t i o n o f oxygen uptake and h e a r t r a t e a t submaximal workload i n t e r v a l s . A c c o r d i n g t o A s t r a n d (4) and Cumming (18) c a l i b r a t i o n o f e l e c t r o n i c b i c y c l e ergometers s h o u l d be done a minimum o f 2 t o 3 times each y e a r . Cumming s t a t e s t h a t " p u l s e r a t e s o r 0£ uptakes o f s u b j e c t s p e r f o r m i n g a s u p p o s e d l y s i m i l a r workload cannot be v a l i d l y compared i f the workload i s up t o 20% i n . e r r o r . " ( 1 8 ) . He f u r t h e r s t a t e s t h a t two h e a v i l y used e l e c t r o n i c ergometers he c a l i b r a t e d were o n l y 10% i n e r r o r 4 t o 8 y e a r s a f t e r f a c t o r y c a l i b r a t i o n (18). The i n f e r e n c e i s t h a t a small c a l i b r a t i o n e r r o r would not g r e a t l y e f f e c t c o m p a r a t i v e d a t a 23 TABLE 1 CALCULATION OF PEDALLING FREQUENCY AND FRICTION FACTOR CORRECTIONS A. P e d a l l i n g Frequency C o r r e c t i o n F a c t o r : 1 kp • 50 rpm • 6 meters= 300 kpm/min . (50 watts= 300 kpm/min) x kp • 60 rpm • 6 meters= 300 kpm/min x kp= 300 kpm/min 60 rpm • 6 meters = .83 C o r r e c t i o n f a c t o r f o r p e d a l l i n g f r e q u e n c y o f 60 rpm= .8_3 B. F r i c t i o n C o r r e c t i o n F a c t o r : A c c o r d i n g t o A s t r a n d (7) a workload o f 600 kpm i s a c t u a l l y 650 kpm, 1200 kpm i s 1300 kpm, e t c . , due t o f r i c t i o n a l l o s s e s i n t h e c h a i n and b e a r i n g s . A l t h o u g h t h i s i s s t a t e d f o r a p e d a l l i n g f r e q u e n c y o f 50 rpm, t h e r e i s no a p p r e c i a b l e change i n the f r i c t i o n f a c t o r from 50 t o 60 rpm ( 1 4 ) . T h e r e f o r e , t he a p p r o p r i a t e r a t i o i s 600 = .92_ 650 C o r r e c t i o n f a c t o r f o r f r i c t i o n l o s s e s = .92^ C. Combined C o r r e c t i o n F a c t o r : .83 •.92= .76 T h e r e f o r e , t he combined c o r r e c t i o n f a c t o r f o r f r i c t i o n l o s s e s and p e d a l l i n g f r e q u e n c y o f 60 rpm = .76^ For p r a c t i c a l a p p l i c a t i o n , the s i n u s b a l a n c e o f the Monark ergometer was marked a t .75 kp f o r the f i r s t w o r k l o a d , and each s u c c e s s i v e workload s e t t i n g was i n c r e a s e d by .75 kp. D. A d j u s t e d Workload S e t t i n g s : Monark D y n a v i t Load 1 .75 kp 50 watts 2 3 4 5 6 1.50 2.25 3.00 3.75 4.50 100 150 200 250 300 24 a n a l y s i s , and i t f o l l o w s t h a t t h e p r o b a b i l i t y o f the newly c a l i b r a t e d D y n a v i t ergometer r e s u l t i n g i n i n a c c u r a t e r e s u l t s i s v e r y low. A Q uinton t r e a d m i l l was used i n c r i t e r i o n d e t e r m i n a t i o n o f peak oxygen consumption, and i s c a l i b r a t e d a t r e g u l a r i n t e r v a l s by l a b o r a t o r y s t a f f . A Beckman M e t a b o l i c Measurement C a r t , i n t e r f a c e d w i t h a H e w l e t t -Packard 3052-A Data A c q u i s i t i o n System, r e c o r d e d the a p p r o p r i a t e p h y s i o l o g i c a l . p a r a m e t e r s under c o n s i d e r a t i o n , and an A v i o n i c s 4000 E l e c t r o -c a r d i o g r a p h was used t h r o u g h o u t the t e s t i n g s e s s i o n s t o m o n i t o r c a r d i o -v a s c u l a r response t o e x e r c i s e . These p i e c e s o f equipment- are a l s o c a l i b r a t e d l a t r e g u l a r i n t e r v a l s by l a b o r a t o r y s t a f f . E x p e r i m e n t a l C o n d i t i o n s Each s u b j e c t d i d t h r e e t e s t s , i n v o l v i n g one maximal e x e r c i s e bout on each o f t h r e e p i e c e s o f equipment; the t r e a d m i l l , t h e D y n a v i t b i c y c l e ergometer and t h e Monark b i c y c l e ergometer. B e f o r e t h i s , each s u b j e c t was i n f o r m e d o f a p p r o p r i a t e p r e - t e s t a c t i v i t y and d i e t a r y g u i d e l i n e s t o f o l l o w (8,69). The l a b o r a t o r y e n v i r o n m e n t a l c o n d i t i o n s (temperature and h u m i d i t y ) were h e l d r e l a t i v e l y c o n s t a n t t h r o u g h o u t the t e s t i n g s e s s i o n s . Each s u b j e c t was a s s i g n e d ' a t r e a t m e n t o r d e r v i a a L a t i n Square D e s i g n , t o negate o r d e r i n g and l e a r n i n g e f f e c t s ( 2 8 ) . See T a b l e 2 f o r assignment o f t r e a t m e n t o r d e r s . ' S u b j e c t s were brought i n t o the l a b o r a t o r y p r i o r t o the t e s t i n g s e s s i o n so t h a t age, h e i g h t , w e i g h t , body f a t and. l e g l e n g t h c o u l d be i d e n t i f i e d and r e c o r d e d . Other f i t n e s s parameters were a l s o t e s t e d and r e c o r d e d f o r t h e b e n e f i t o f the p a r t i c i p a n t s . A c o n s e n t form, b r i e f m e d i c a l h i s t o r y form (PAR Q) and an a c t i v i t y q u e s t i o n a i r e were a d m i n i s t e r e d , f o l l o w e d by f a m i l i a r i z a t i o n o f the s u b j e c t w i t h the a p p r o p r i a t e t e s t i n g a p p a r a t u s . The e l e c t r o c a r d i o g r a p h • l e a d s were then a p p l i e d and the s u b j e c t was informed o f TABLE 2 ORDER OF TESTS FOR SUBJECTS (REPEATED LATIN SQUARE DESIGN) 25 S u b j e c t s 1 & 7 2 & 8 3 & 9 4 & 10 5 & 11 6 & 12 13 T e s t 1 D y n a v i t Monark Treadmi11 T r e a d m i l l Monark D y n a v i t D y n a v i t T e s t 2 Monark T r e a d m i l l D y n a v i t Monark D y n a v i t T r e a d m i l l Monark T e s t 3 Treadmi11 D y n a v i t Monark D y n a v i t T r e a d m i l l Monark Treadmi11 26 the p r o c e d u r e r e q u i r e d t o complete the t e s t . In t h e case o f the b i c y c l e t e s t s , s a d d l e h e i g h t was i n i t i a l l y e s t a b l i s h e d by the method put f o r w a r d by Shennum and de V r i e s (68). Leg l e n g t h was determined by measuring the v e r t i c a l d i s t a n c e from the i s c h i u m t o t h e f l o o r , i d e n t i f i c a t i o n o f the i s c h i u m b e i n g a c h i e v e d by p a l p a t i o n . The ergometer pedal was then moved t o i t s most d i s t a l p o s i t i o n from t h e s e a t , and the d i s t a n c e from the t o p - f r o n t o f the s e a t t o the t o p o f t h e pedal ( a t a p o i n t d i r e c t l y t h r o u g h the pedal a x i s ) was a d j u s t e d , w i t h s e a t h e i g h t b e i n g s e t at~104% o f l e g l e n g t h . T h i s method a g r e e s w e l l w i t h t h o s e put f o r w a r d by Hamley and Thomas (35) and by A s t r a n d ( 7 ) . The h a n d l e b a r s were m a i n t a i n e d i n one r e l a t i v e l y n e u t r a l p o s i t i o n ( 7 ) . E x p e r i m e n t a l P r o c e d u r e s The t r e a d m i l l p r o c e d u r e i n v o l v e d a c o n t i n u o u s , i n c r e m e n t a l p r o t o c o l , d e s i g n e d t o produce e x h a u s t i o n i n 10-15 minutes. The s u b j e c t i n i t i a l l y completed a 10 minute warm-up walk a t 3.5 mph and 0% grade. T h i s was f o l l o w e d by attachment o f the Rudolph b r e a t h i n g a p p a r a t u s . The speed o f the t r e a d m i l l was then i n c r e a s e d t o 7 mph , w i t h 0% grade f o r the f i r s t 3 minutes o f t h e t e s t . T h e r e a f t e r the grade was i n c r e a s e d by 2.5% e v e r y 3 minutes t o v o l i t i o n a l f a t i g u e o r p h y s i o l o g i c a l c o n t r a i n d i c a t i o n ( 1 ) . The b i c y c l e ergometer e x e r c i s e t e s t was i d e n t i c a l f o r both b i c y c l e s , and was o f a c o n t i n u o u s , i n c r e m e n t a l n a t u r e . A 10 minute warm-up was completed i n i t i a l l y a t a workload s e t t i n g o f .75 kp on the s i n u s b a l a n c e o f the Monark, o r 50 wa t t s on t h e D y n a v i t d i g i t a l d i s p l a y . P e d a l l i n g f r e q u e n c y was m a i n t a i n e d a t 60 rpm t h r o u g h o u t a l l t e s t s by the use o f a metronome, which was checked f o r c a l i b r a t i o n b e f o r e each t e s t . A f t e r the warm-up, the Rudolph b r e a t h i n g a p p a r a t u s was a t t a c h e d . The i n i t i a l 3 minute workload was 27 s e t a t .75 kp on the s i n u s b a l a n c e o f the Monark, o r 50 w a t t s on the D y n a v i t d i g i t a l d i s p l a y . T h e r e a f t e r the r e s i s t a n c e was i n c r e a s e d by .75 kp on the Monark o r 50 Watts on the D y n a v i t e v e r y 3 minutes u n t i l v o l i t i o n a l f a t i g u e , l o s s o f a p p r o p r i a t e p e d a l l i n g cadence o r p h y s i o l o g i c a l c o n t r a i n d i c a t i o n ( 1 ) . A r e v o l u t i o n c o u n t e r was i n c l u d e d on each b i c y c l e ergometer t e s t t o a l l o w f o r p e d a l l i n g f r e q u e n c y guidance from minute t o minute d u r i n g each t e s t , as w e l l as f o r r e t r o s p e c t i v e a n a l y s i s o f e x e r c i s e e n d p o i n t s i n q u e s t i o n a b l e c a s e s . Only one such case o c c u r r e d , the t e s t e n d p o i n t b e i n g r e s o l v e d as the minute mark p r i o r t o t h e l o s s o f c o r r e c t p e d a l l i n g cadence. A s t a n d a r d d e v i a t i o n o f p l u s o r minus 5 rpm was a l l o w e d , and s u b j e c t DD d e f i n i t e l y l o s t more than 5 rpm a f t e r minute 18 o f the D y n a v i t t e s t . A l l s u b j e c t s were encouraged t o proceed as l o n g as p o s s i b l e , w i t h the knowledge t h a t t h e y c o u l d d i s c o n t i n u e a t any time. A s u b j e c t i v e a c c o u n t o f reasons f o r d i s c o n t i n u i n g each t e s t was o b t a i n e d from a l l s u b j e c t s on each a p p a r a t u s , f o r r e t r o s p e c t i v e a n a l y s i s . See Appendix A f o r an o u t l i n e o f the S u b j e c t i v e Response Q u e s t i o n a i r e . E x p e r i m e n t a l Design The main problem, which examined peak oxygen consumption and t o t a l work time i n d e p e n d e n t l y , i n v o l v e d a s i n g l e f a c t o r experiment w i t h r e p e a t e d measures. See F i g u r e 4 f o r a d i a g r a m a t i c i l l u s t r a t i o n o f t h i s d e s i g n . The sub-problems i n c l u d e d e x a m i n a t i o n o f submaximal h e a r t r a t e and oxygen uptake i n d e p e n d e n t l y , and i n v o l v e d a 3 by 7 f a c t o r i a l e x p e r i m e n t , w i t h r e p e a t e d measures on both f a c t o r s . See F i g u r e 5 f o r a d i a g r a m a t i c i l l u s t r a t i o n o f t h i s d e s i g n . 28 D y n a v i t Monark Treadmil1 ST X X X s i X X X S , X X X sf . X X X st X X X si X X X S^ X X X Sp X X X Sg X X X S, X X X Sj!j X X X ^ ^ X s 2 2 ^ ^ X FIGURE 4 EXPERIMENTAL DESIGN: HYPOTHESES 1, 2, 3 AND 4 D y n a v i t Monark Treadmi11 Minute: 1 7 1 7 1 !10 111 112 >13 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X x FIGURE 5 EXPERIMENTAL DESIGN: HYPOTHESES 5 AND 6 29 E x p e r i m e n t a l A n a l y s i s A one way a n a l y s i s o f v a r i a n c e (ANOVA) w i t h r e p e a t e d measures was used t o t e s t the s i g n i f i c a n c e o f the d i f f e r e n c e between means f o r peak oxygen consumption and t o t a l work time. For the d a t a i n v o l v i n g submaximal h e a r t r a t e and oxygen uptake, a two way a n a l y s i s o f v a r i a n c e w i t h repeated 1 measures on both f a c t o r s was employed. The U n i v e r s i t y o f B r i t i s h Columbia Computer Program BMD:P2V was used i n a l l c a s e s , the v a r i a b l e s o f peak oxygen consumption, t o t a l work t i m e , submaximal h e a r t r a t e and submaximal oxygen uptake a l l b e i n g a n a l y z e d i n d e p e n d e n t l y . The Newman-Keuls method o f p r o b i n g the n a t u r e o f the d i f f e r e n c e s be-tween t r e a t m e n t means was used i f a s i g n i f i c a n t o v e r a l l F v a l u e was found f o r any e x p e r i m e n t a l c o n d i t i o n ( 2 8 ) . ( CHAPTER IV RESULTS AND DISCUSSION A n t h r o p o m e t r i c Data T a b l e 3 g i v e s each s u b j e c t ' s age, h e i g h t , w e i g h t , p e r c e n t body f a t and l e g l e n g t h as w e l l as the a s s o c i a t e d group means and s t a n d a r d d e v i a t i o n s . TABLE 3 AGE, HEIGHT, WEIGHT, PERCENT BODY FAT AND LEG LENGTH OF ALL SUBJECTS (PLUS GROUP MEANS AND STANDARD DEVIATIONS) S u b j e c t s A g e ( y r s ) Height(cm) Weight(kg) Body F a t ( % ) Leg Length(cm) DD 26 182.4 77.5 12.3 91.0 BF1 22 179.9 78.5 11.2 89.4 BF2 20 183.5 85.4 13.6 89.5 CH 25 181.5 67.6 08.8 90.3 MH 21 179.8 71.4 12.4 93.1 DL 22 171.6 66.5 ' 12.3 85.8 BA 26 183.2 71.7 12.7 90.4 ML 19 168.2 65.8 11.6 83.9 RB 23 170.5 65.3 11.1 86.8 PV 23 172.7 58.7 11.5 86.2 WK 21 185.9 75.0 14.1 . 100.4 RW 20 170.9 60.7 11.8 84.8 MC 25 178.1 69.9 12.6 88.6 Mean SD 22.5 2.7 177.6 4.2 70.3 7.5 12.0 1..3 . 89.3 2.8 30 31 See Appendix B f o r e x a m i n a t i o n o f the raw p h y s i o l o g i c a l data a s s o c i a t e d w i t h t h i s s t u d y . R e s u l t s o f T o t a l Work Time The means o b t a i n e d f o r t o t a l work time i n t h i s s t u d y a r e g i v e n i n T a b l e 4, as w e l l as the a s s o c i a t e d s t a n d a r d d e v i a t i o n s . The F v a l u e o b t a i n e d from the ANOVA t a b l e i s a l s o i n d i c a t e d . For d e t a i l s o f the complete ANOVA t a b l e see Appendix C. F i g u r e 6 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f the dat a from T a b l e 4. TABLE 4 TOTAL WORK TIME (DECIMAL MINUTES) (MEANS, STANDARD DEVIATIONS AND F VALUES) T o t a l Work Time Mean S t a n d a r d D e v i a t i o n D y n a v i t 15.64 1.20 Monark 15.97 1.51 T r e a d m i l l 10.21 2.34 F Value 92.42* * S i g n i f i c a n t a t <.001 L e v e l The F v a l u e of'92.42 i n d i c a t e d a h i g h l y s i g n i f i c a n t d i f f e r e n c e among tr e a t m e n t means i n t o t a l work-time. A Newman-Keuls T e s t was a p p l i e d t o the data t o determine where the d i f f e r e n c e s among the means o c c u r e d . These r e s u l t s a r e shown i n T a b l e 5. An a n a l y s i s o f the r e s u l t s from T a b l e 5 r e v e a l s t h a t t he t o t a l work 32 25 to CD 3 B o CD Q CD o (0 +-> o 20 15 10 5 .j 1 J ; — l 1 1 J_ Monark T r e a d m i l l D y n a v i t FIGURE 6 TOTAL WORK TIME (DECIMAL MINUTES) (MEANS AND STANDARD DEVIATIONS) 33 time mean a c h i e v e d on the D y n a v i t ergometer was n o t d i f f e r e n t from the t o t a l work time mean o b t a i n e d on the Monark ergometer. Thus h y p o t h e s i s 1 as s t a t e d i n C h a p t e r 1 s h o u l d be r e j e c t e d . TABLE 5 TOTAL WORK TIME (DECIMAL MINUTES) NEWMAN-KEULS TEST (TREATMENT MEANS IN ORDER) T r e a d m i l l (10.21) T r e a d m i l l D y n a v i t Monark D y n a v i t Monark (15.64) (15.97) 15.97* 16.94* .97 * S i g n i f i c a n t a t .05 L e v e l The t o t a l work' time means a c h i e v e d on both the D y n a v i t and Monark ergometers were g r e a t e r than the mean time o b t a i n e d on the t r e a d m i l l . T h i s i s a p o i n t o f i n t e r e s t , but o f no d i r e c t importance t o the s t u d y . D i s c u s s i o n o f T o t a l Work Time R e s u l t s One o f ; t h e major assumptions s t a t e d i n t h i s s t u d y was t h a t an i n c r e a s e i n t o t a l work time d u r i n g maximal b i c y c l e e x e r c i s e would r e s u l t , i n g r e a t e r p h y s i c a l e x e r t i o n and thus the achievement o f a h i g h e r peak oxygen consump-t i o n v a l u e on the D y n a v i t ergometer than on the Monark ergometer. The r e s u l t s i n d i c a t e t h a t such was not t h e case.- No d i f f e r e n c e was found between the t o t a l work times o f the two b i c y c l e e r g o m e t e r s , thus b r i n g i n g i n t o doubt the 34 p o s s i b i l i t y t h a t peak oxygen consumption v a l u e s would d i f f e r . S i n c e no d i f f e r e n c e was found i n t o t a l work t i m e s , i t would appear t h a t the l e v e l o f p h y s i c a l e x e r t i o n must be s i m i l a r f o r the two t y p e s o f b i c y c l e s . I f t h i s i s t r u e , then t h e r e i s l i t t l e reason t o e x p e c t d i f f e r e n c e s i n the o t h e r maximal p h y s i o l o g i c a l parameters which were examined. As p r e v i o u s l y mentioned, the t r e a d m i l l t o t a l work time was much l e s s than e i t h e r o f the c o r r e s p o n d i n g Monark o r D y n a v i t v a l u e s . T h i s can be e x p l a i n e d i n p a r t by the i n h e r e n t b i o m e c h a n i c a l d i f f e r e n c e s i n v o l v e d i n the two t y p e s o f a c t i v i t y ( r u n n i n g and c y c l i n g ) . The u p h i l l r u n n i n g , w i t h i n the c o n t e x t o f t h i s s t u d y , p r o b a b l y r e q u i r e d a h i g h e r r e l a t i v e i n t e n s i t y o f e f f o r t and t h u s a g r e a t e r energy e x p e n d i t u r e per u n i t time than the c y c l i n g d i d . I t would appear t h a t a l t h o u g h an attempt was made to equate the two t y p e s o f e x e r c i s e t e s t p r o t o c o l ( b i c y c l e and t r e a d m i l l ) , t h i s was n o t t o t a l l y a c h i e v e d , as s u g g e s t e d by the d i f f e r e n c e i n t o t a l work time j u s t n o t e d . T h i s was not o f s t r a t e g i c c o n c e r n , however, i n the e x a m i n a t i o n o f the o v e r a l l r e s u l t s . R e s u l t s o f Peak Oxygen Consumption Data ^ The means f o r peak oxygen consumption, as w e l l as the a s s o c i a t e d s t a n d a r d d e v i a t i o n s o b t a i n e d i n t h i s s t u d y are g i v e n i n T a b l e 6. The F v a l u e o b t a i n e d from the ANOVA t a b l e i s a l s o i n d i c a t e d . For d e t a i l s o f the complete ANOVA t a b l e see Appendix C. F i g u r e . 7 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f t h e d a t a from T a b l e 6. The F v a l u e o f 5.42 i n d i c a t e d a s t a t i s t i c a l d i f f e r e n c e among t r e a t m e n t means i n peak oxygen consumption. A Newman-Keuls T e s t was a p p l i e d t o the d a t a t o determine where the d i f f e r e n c e s among,the means o c c u r r e d . These r e s u l t s a r e shown i n T a b l e 7. 35 50 40 35 30 Monark T r e a d m i l l D y n a v i t FIGURE 7 PEAK OXYGEN CONSUMPTION (ML/KG/MIN) ^  (MEANS AND STANDARD DEVIATIONS) \ 36 TABLE 6 PEAK,OXYGEN CONSUMPTION (ML/KG/MIN) (MEANS, STANDARD DEVIATIONS AND F VALUES) D y n a v i t Monark T r e a d m i l l F V a l u e POC Mean 46.86 45.57 49.85 5.42* S t a n d a r d D e v i a t i o n 5.92 7.11 4.92 * . S i g n i f i c a n t a t .0114 L e v e l TABLE 7 PEAK OXYGEN CONSUMPTION (ML/KG/MIN) NEWMAN-KEULS TEST (TREATMENT MEANS IN ORDER) Monark (45.57) Monark D y n a v i t T r e a d m i l l D y n a v i t • T r e a d m i l l (46.86) (49.85) 1.37 4.55* 3.18* * S i g n i f i c a n t a t .05 L e v e l . An a n a l y s i s o f the p r e c e e d i n g r e s u l t s r e v e a l s t h a t the peak oxygen consumption mean a c h i e v e d on the D y n a v i t ergometer was n o t s t a t i s t i c a l l y d i f f e r e n t from the mean o b t a i n e d on the Monark ergometer. Thus h y p o t h e s i s 2 37 as s t a t e d i n Chapte r 1 s h o u l d be r e j e c t e d . T a b l e 7 a l s o r e v e a l s t h a t t h e peak oxygen consumption mean o b t a i n e d on the t r e a d m i l l was d i f f e r e n t from ( g r e a t e r than) t he mean o b t a i n e d on the Monark ergometer. Thus h y p o t h e s i s 3 as s t a t e d i n Chapter 1 s h o u l d be a c c e p t e d . F i n a l l y , t h e p r e c e e d i n g T a b l e 7 shows t h a t t h e peak oxygen consumption mean o b t a i n e d on the t r e a d m i l l was d i f f e r e n t from ( g r e a t e r than) t he mean o b t a i n e d on the D y n a v i t ergometer. On t h i s b a s i s h y p o t h e s i s 4 as s t a t e d i n Chapter 1 s h o u l d be r e j e c t e d . D i s c u s s i o n o f Peak Oxygen Consumption R e s u l t s A n a l y s i s o f the peak oxygen consumption d a t a i n d i c a t e s t h a t d u r i n g the maximal e x e r c i s e t e s t i n g t h e r e was no app a r e n t d i f f e r e n c e between t he D y n a v i t and Monark ergometers i n the s u b j e c t ' s p h y s i o l o g i c a l r e s p o n s e t o e x e r c i s e s t r e s s , as i n d i c a t e d by the l a c k o f d i f f e r e n c e i n the above v a l u e s . T h i s c o n c l u s i o n s u p p o r t s t he c o n t e n t i o n t h a t t h e r e i s no p r a c t i c a l d i f f e r e n c e i n the l o a d i n g systems o f the two t y p e s o f b i c y c l e e r g o m e t e r s , as was o r i g i n a l l y proposed. The peak oxygen consumption v a l u e a c h i e v e d on the t r e a d m i l l was g r e a t e r than t h a t which was a c h i e v e d on the Monark ergometer,' a c o n c l u s i o n which i s i n agreement w i t h p r e v i o u s l y r e p o r t e d l i t e r a t u r e . A l t h o u g h t he magnitude o f the d i f f e r e n c e s between b i c y c l e and t r e a d m i I T v a l u e s o f maximal oxygen uptake v a r y from 5 t o 15% (39,52), t he more commonly r e p o r t e d v a l u e s a r e more i n t h e range o f 5 t o 8% (38). The peak oxygen consumption v a l u e r e c o r d e d f o r t h e Monark i n t h i s s t u d y (45.57 ml/kg/min) was 8.6% lower than t h a t a c h i e v e d on the t r e a d m i l l (49.85 ml/kg/min). I t was found t h a t t he peak oxygen consumption s c o r e a t t a i n e d on the 38 D y n a v i t ergometer was a l s o lower than t h a t o b t a i n e d on the t r e a d m i l l . The magnitude o f the d i f f e r e n c e was 6%. These f i n d i n g s s u g g e s t t h a t the l o a d i n g • c h a r a c t e r i s t i c s o f the D y n a v i t a r e n o t d i f f e r e n t from t h o s e o f the Monark i n t h e i r i n f l u e n c e upon the m u s c u l a r f u n c t i o n o r o t h e r a s p e c t s o f the c a r d i o -v a s c u l a r dynamics o f u n t r a i n e d young men. R e s u l t s o f Submaximal Oxygen Uptake Data T a b l e 8 shows the means and s t a n d a r d d e v i a t i o n s f o r submaximal oxygen u p t a k e - ( m l / k g / m i n ) , minutes 1 through 7, f o r the D y n a v i t and Monark ergometers. F i g u r e 8 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f the data from T a b l e 8. O n l y v a l u e s f o r minutes 1 t h r o u g h 7 a r e shown, as beyond t h i s p o i n t h e a r t r a t e r e s p o n s e s f o r a l l s u b j e c t s d i d n o t remain w i t h i n the l i m i t s s e t by the d e f i n i t i o n o f Submaximal Oxygen Uptake (see C h a p t e r 1, D e f i n i t i o n s ) . TABLE 8 SUBMAXIMAL OXYGEN UPTAKE (ML/KG/MIN) (MEANS, AND STANDARD DEVIATIONS) • D y n a v i t Monark Mean SD Mean SD Minute 1 Minute 2 Minute 3 Minute 4 Minute 5 Minute 6 Minute 7 12.86 12.91 12.87 15.01 18.89 20.62 24.39 2.61 2.30 2.53 4.00 2.60 3.79 3.71 11.17 13.21 13.27 15.65 19.03 20.50 23.54 2.40 3.29 2.53 2.54 3.41 2.86 3.77 T a b l e 9 shows the ANOVA data and a s s o c i a t e d p r o b a b i l i t y v a l u e s f o r the Monark: 35 D y n a v i t : 25 A 20 H 15 H io. H 4-2 3 4 5 Time (minutes) FIGURE 8 SUBMAXIMAL OXYGEN UPTAKE (ML/KG/MIN) 40 submaximal oxygen uptake r e s u l t s . TABLE 9 ANOVA TABLE FOR SUBMAXIMAL OXYGEN UPTAKE Source Sum o f Squares d f Mean Square F Prob. F Exceeded Minutes(M) 3198.44 6 533.07 82.59 <.001* M L i n e a r 2989.99 1 2989.99 204.35 <.001* M Q u a d r a t i c 155.57 1 155.57 39.18 . < :ooi* B i k e s ( B ) 1.30 1 1.30 .20 . 6648 MXB 26.50 6 4.42 1.04 .4044 * S i g n i f i c a n t a t <.001 The ANOVA-table i n d i c a t e s t h a t f o r each b i k e t h e r e was a d i f f e r e n c e i n submaximal oxygen uptake from minute t o minute, as was e x p e c t e d , s i n c e t he t e s t was d e s i g n e d t o do t h i s . But t h e r e was no o v e r a l l d i f f e r e n c e i n oxygen uptake, o r i n the r a t e o f change o f oxygen uptake from minute t o minute, between the two b i c y c l e s . Thus h y p o t h e s i s 5 as s t a t e d i n C h a p t e r 1 s h o u l d be r e j e c t e d . D i s c u s s i o n o f Submaximal Oxygen Uptake R e s u l t s The p r e c e e d i n g r e s u l t s i n d i c a t e t h a t a t submaximal workloads t h e r e i s no d i f f e r e n c e between t he two b i c y c l e s i n the s u b j e c t ' s p h y s i o l o g i c a l r e s ponse t o e x e r c i s e , as e x p r e s s e d i n terms o f oxygen uptake. From T a b l e 9 i t can be seen t h a t t h e Min u t e s e f f e c t ( the change i n oxygen uptake from minute t o minute) can b e s t be d e s c r i b e d - b y a l i n e a r f u n c t i o n (M L i n e a r : p<.001). S i n c e oxygen uptake i n c r e a s e s i n a l i n e a r f a s h i o n w i t h i n c r e a s e s i n work-l o a d (as does h e a r t r a t e ) ( 8 ) , and s i n c e t h e r e was no d i f f e r e n c e i n sub-maximal oxygen uptake between the two b i c y c l e s , i t f o l l o w s t h a t t he b i c y c l e s c o u l d be used i n t e r c h a n g e a b l y f o r submaximal p r e d i c t i v e t e s t i n g o f a e r o b i c work c a p a c i t y . R e s u l t s o f Submaximal Heart Rate Data T a b l e 10 shows the means and s t a n d a r d d e v i a t i o n s f o r submaximal h e a r t r a t e (bpm), minutes 1 thro u g h 7, f o r the D y n a v i t and Monark ergometers. F i g u r e 9 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f the dat a from T a b l e 10. Only the f i r s t 7 minutes o f the h e a r t r a t e d a t a a r e shown i n T a b l e 10 because beyond t h i s p o i n t h e a r t r a t e r e s p o n s e s f o r a l l s u b j e c t s d i d not remain w i t h i n t he l i m i t s s e t by the d e f i n i t i o n o f Submaximal Heart Rate (see Chapt e r 1, D e f i n i t i o n s ) . TABLE 10 SUBMAXIMAL HEART RATE (BPM) (MEANS AND STANDARD DEVIATIONS) D y n a v i t Monark Mean SD Mean SD Minute 1 Minute 2 Minute 3 Minute 4 Minute 5 Minute 6 Minute 7 109.08 108.92 110.77 121.46 127.15 132.77 146.23 14.19 12.91 12.45 11.20 9.92 14.28 13.85 106.15 8.30 107.15 7.54 110.15 8.46 121.46 9.67 123.92 12.50 129.31 13.57 140.69 12.71 Monark: D y n a v i t : 150 100 H 90 ] 1 , , —) 1 1 1 2 3 4 5 6 7 Time (minutes) FIGURE 9 SUBMAXIMAL HEART RATE (BPM) 43 T a b l e 11 shows the ANOVA data and a s s o c i a t e d p r o b a b i l i t y v a l u e s f o r the submaximal h e a r t r a t e r e s u l t s . TABLE 11 ANOVA TABLE FOR SUBMAXIMAL HEART RATE Source Sum o f Squares d f Mean Square F Prob. F Exceeded Minutes(M) 28190.67 6 4698.45 137.13 < 0 0 1 * M L i n e a r 26400.35 1 26400.35 179.45 < 0 0 1 * M Q u a d r a t i c 1172.16 1 1172.16 104.57 < 0 0 1 * B i k e s ( B ) 285.63 1 285.63 1.71 .2158 M X B 137.84 6 22.97 1.03 .4123 * S i g n i f i c a n t a t < . 0 0 1 The ANOVA t a b l e i n d i c a t e s t h a t t h e r e was a h i g h l y s i g n i f i c a n t d i f f e r e n c e i n submaximal h e a r t r a t e from minute t o minute f o r each b i k e , which was t o be expe c t e d . However, the r e s u l t s a l s o i n d i c a t e t h a t t h e r e was no o v e r a l l d i f f e r e n c e i n h e a r t r a t e s between the two b i c y c l e s , and t h a t t he r a t e o f change from minute t o minute o f h e a r t r a t e s d i d not d i f f e r s i g n i f i c a n t l y . Thus h y p o t h e s i s 6 as s t a t e d i n C h a p t e r 1 s h o u l d be r e j e c t e d . D i s c u s s i o n o f Submaximal Heart Rate R e s u l t s When t h e s e r e s u l t s a r e p l a c e d i n t o t he c o n t e x t o f submaximal e x e r c i s e t e s t i n g ( M o d i f i e d S j o s t r a n d PWC T e s t , Astrand-Ryhming P r e d i c t e d Oxygen Uptake T e s t ) , i t would appear t h a t t he D y n a v i t b i c y c l e e l i c i t s submaximal h e a r t r a t e r e s p o n s e s which a r e s i m i l a r t o t h o s e produced from t he Monark ergometer. 44 From T a b l e 11 i t can be seen t h a t the Minutes e f f e c t (the change i n h e a r t r a t e from minute t o minute) can b e s t be d e s c r i b e d by a l i n e a r f u n c t i o n (M L i n e a r : p<.001). As the above mentioned submaximal e x e r c i s e t e s t s a r e based on a l i n e a r h e a r t r a t e response t o e x e r c i s e s t r e s s , i t would appear t h a t the D y n a v i t c o u l d be used i n t e r c h a n g e a b l y w i t h t h e Monark f o r the a d m i n i s t r a t i o n o f such t e s t s . A s t u d y by Hockey (40) has shown good r e l i a b i l i t y and p r e d i c t i o n f a c t o r s f o r the D y n a v i t on a 10 minute submaximal t e s t , and MacLeod (53) has r e p o r t e d the D y n a v i t t o be r e l i a b l e f o r submaximal t e s t i n g purposes. The r e s u l t s o f a study by C a r r o l l (15) s u g g e s t t h a t a c o n s t a n t p e d a l l i n g f r e q u e n c y s h o u l d be m a i n t a i n e d d u r i n g such t e s t s however, as he found t h a t the c o n s t a n t l o a d i n g system o f the Elema-Schonander b i c y c l e ergometer was not a c c u r a t e i f p e d a l l i n g f r e q u e n c y was v a r i e d . R e s u l t s o f Maximal Heart Rate Data T a b l e 12 shows the means and s t a n d a r d d e v i a t i o n s f o r maximal h e a r t r a t e f o r a l l t h r e e p i e c e s o f t e s t i n g equipment. The F v a l u e o b t a i n e d from the ANOVA data i s a l s o i n d i c a t e d i n t h e t a b l e . See Appendix C f o r e x a m i n a t i o n o f the complete ANOVA t a b l e . F i g u r e 10 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f the d a t a from T a b l e 12. The F v a l u e o f 13.61 i n d i c a t e d a h i g h l y s i g n i f i c a n t d i f f e r e n c e among tr e a t m e n t means f o r maximal h e a r t r a t e . A Newman-Keuls T e s t was a p p l i e d t o the d a t a t o determine where the d i f f e r e n c e s among the means ©ccurred. These r e s u l t s a r e shown i n T a b l e 13. E x a m i n a t i o n o f the r e s u l t s shows t h a t t h e r e was a d i f f e r e n c e i n maximal h e a r t r a t e between the Monark and the t r e a d m i l l , the l a t t e r mean b e i n g 11.23 bpm h i g h e r . There was no d i f f e r e n c e found between the D y n a v i t and the t r e a d -m i l l mean s c o r e s f o r maximal h e a r t r a t e , a l t h o u g h the C a l c u l a t e d Q f o r the 45 220 -t 210 H B CL S -CD 200 190 180 Monark T r e a d m i l l FIGURE 10 MAXIMAL HEART RATE (BPM) (MEANS AND STANDARD DEVIATIONS) D y n a v i t i n t e r a c t i o n was 2..88, w h i l e the C r i t i c a l Q was o n l y 2.92. Thus i t would appear t h a t the d i f f e r e n c e was n e a r l y s i g n i f i c a n t a t t h e .05 l e v e l . TABLE 12 MAXIMAL HEART RATE (BPM) (MEANS, STANDARD DEVIATIONS AND F VALUES) Dynavi t Monark T r e a d m i l l F V a l u e Mean 197.39 192.92 204.15 13.61* SD 9.97 11.27 11.40 * S i g n i f i c a n t a t < . 0 0 1 L e v e l TABLE 13 MAXIMAL HEART RATE (BPM) NEWMAN-KEULS TEST (TREATMENT MEANS IN ORDER) Monark D y n a v i t T r e a d m i l l MOnark (.192.92) D y n a v i t (197.39) 1.90 Treadmi11 (204.15) 4.77* 2.88 * S i g n i f i c a n t a t .05 Le v e l 47 I t was a l s o found t h a t no d i f f e r e n c e e x i s t e d between the D y n a v i t and Monark ergometers i n terms o f maximal h e a r t r a t e . D i s c u s s i o n o f Maximal Heart Rate R e s u l t s A l t h o u g h not a c e n t r a l f a c t o r i n the t h e s i s , the maximal h e a r t r a t e d a t a s u g g e s t e d t h a t a s t a t i s t i c a l a n a l y s i s s h o u l d be done t o e l u c i d a t e any p o s s i b l e d i f f e r e n c e s . As r e p o r t e d , the t r e a d m i l l mean f o r maximal h e a r t r a t e was s i g n i f i c a n t l y h i g h e r than the Monark ergometer. T h i s r e s u l t f i n d s some su p p o r t i n the l i t e r a t u r e (11,56,60,61), but not unanimously so (9,32,38, 39,52). One p o s s i b l e e x p l a n a t i o n f o r t h i s l a c k o f agreement i s t h a t many d i f f e r e n t types o f b i c y c l e and t r e a d m i l l t e s t p r o t o c o l s were used i n the v a r i o u s papers examined, thus l i m i t i n g comparisons w i t h t he p r e s e n t s t u d y , o r w i t h each o t h e r . A l s o , t h e n a t u r e and e x t e n t o f t r a i n i n g o f the s u b j e c t s i n v o l v e d i n t h e s e s t u d i e s v a r i e d enormously, l i m i t i n g comparison even more. The f i n d i n g t h a t the D y n a v i t maximal h e a r t r a t e mean was not s t a t i s t -i c a l l y d i f f e r e n t from t h e t r e a d m i l l does not appear to be i n l i n e w i t h t he r e s u l t s o f the o t h e r parameters examined i n the hypotheses. However, f o r a l e v e l o f c o n f i d e n c e o f .05, the C a l c u l a t e d Q v a l u e o f 2.88 was s u f f i c i e n t l y c l o s e to the C r i t i c a l Q v a l u e o f 2.92 t o pose the p o s s i b i l i t y o f a Type II e r r o r i f the n u l l h y p o t h e s i s was a c c e p t e d . C h o i c e o f a l e v e l o f c o n f i d e n c e o f .06 would have r e s u l t e d i n 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 d i f f e r e n c e between the D y n a v i t and t r e a d m i l l maximal h e a r t r a t e v a l u e s . The r e s u l t s a l s o i n d i c a t e t h a t t h e r e was no d i f f e r e n c e i n maximal h e a r t r a t e between the D y n a v i t and Monark ergometers, a f i n d i n g which i s i n a g r e e -ment w i t h the o t h e r parameters which were i n v e s t i g a t e d . R e s u l t s o f Submaximal Oxygen P u l s e Data T a b l e 14 i n d i c a t e s the means and s t a n d a r d d e v i a t i o n s f o r submaximal oxygen p u l s e f o r a l l t h r e e p i e c e s o f the t e s t i n g equipment. F i g u r e 11 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f the da t a from T a b l e 14. The submaximal oxygen p u l s e d a t a was determined by d i v i d i n g the oxygen uptake s c o r e s (ml/min) f o r each minute o f submaximal e x e r c i s e by t h e c o r r e s p o n d i n g submaximal h e a r t r a t e s c o r e s (bpm). TABLE 14 SUBMAXIMAL OXYGEN PULSE (ML/BEAT) (MEANS AND STANDARD DEVIATIONS) D y n a v i t Monark T r e a d m i l l Mean SD Mean SD Mean SD Minute 1 9.04 2.14 7.62 1.52 15.63 2.19 Minute 2 9.06 1.15 8.88 1.72 15.83 1.53 Minute 3 8.91 1.70 8.81 2.06 15.62 2.07 Minute 4 9.36 2.25 9.37 1.50 15.99 2.00 Minute 5 11.30 1.69 11.08 1.62 16.41 2.02 Minute 6 11.79 1.90 11.55 1.73 16.41 2.02 Minute 7 12.65 1.55 12.15 1.86 17.04 2.08 T a b l e 15 shows the ANOVA data and a s s o c i a t e d p r o b a b i l i t y v a l u e s f o r t h e submaximal oxygen p u l s e r e s u l t s . I t i s c l e a r t h a t t h e r e was a s t a t i s t i c a l d i f f e r e n c e i n submaximal oxygen p u l s e from minute t o minute f o r each b i k e , which i s t o be e x p e c t e d . The t a b l e a l s o shows t h a t t h e r e was no d i f f e r e n c e o v e r a l l i n submaximal oxygen p u l s e between the two b i c y c l e s , and t h a t the r a t e o f change from minute t o minute i n oxygen p u l s e d i d not d i f f e r s t a t i s t i c a l l y . Monark: D y n a v i t : __ Treadmi11:® ® ® ® + 1 1 ) 1 : h 1 2 3 4 5 6 Time (minutes) FIGURE 11 SUBMAXIMAL OXYGEN PULSE (ML/BEAT) -50 TABLE 15 ANOVA TABLE FOR SUBMAXIMAL OXYGEN PULSE Source Sum o f Squares d f Mean Square F Prob. F Exceeded Minutes(M) 401.42 6 66. 90 31.31 <.001* M L i n e a r 369.45 .1 369. 45 100.11 <.001* M Q u a d r a t i c 11.23 1 11. 23 5.91 .0317 B i k e s ( B ) 6.57 1 6. 57 1.62 .2272 MXB 9.26 6 1. 54 .95 .4674 * S i g n i f i c a n t a t C O O l D i s c u s s i o n o f Submaximal Oxygen P u l s e R e s u l t s A l t h o u g h an e x a m i n a t i o n o f oxygen p u l s e was not a c e n t r a l a s p e c t o f t h i s t h e s i s , i t was f e l t t h a t a s t a t i s t i c a l a n a l y s i s s h o u l d be done t o c l a r i f y any p o s s i b l e d i f f e r e n c e s between the two b i c y c l e s . Oxygen p u l s e i s o f t e n used as an i n d i r e c t i n d i c a t o r o f s t r o k e volume, and as such may be used t o h e l p i l l u m i n a t e the r o l e o f c a r d i a c performance i n e x e r c i s e . The p r e c e e d i n g r e s u l t s s u g g e s t t h a t t h e r e i s l i t t l e d i f f e r e n c e i n c a r d i a c performance as i t r e l a t e s t o submaximal e x e r c i s e on e i t h e r the D y n a v i t o r Monark ergometers. And, s i n c e both submaximal oxygen uptake and h e a r t r a t e response t o e x e r c i s e a r e g e n e r a l l y l i n e a r i n n a t u r e , i t i s u n d e r s t a n d a b l e t h a t the submaximal oxygen p u l s e d a t a can b e s t be e x p l a i n e d i n terms o f a l i n e a r f u n c t i o n , as i n d i c a t e d by T a b l e 15. I t i s noteworthy t h a t the submaximal oxygen p u l s e v a l u e s a c h i e v e d on the t r e a d m i l l were much h i g h e r than t h o s e a t t a i n e d on e i t h e r o f the b i c y c l e ergometers. T h i s f i n d i n g i s i n agreement w i t h o t h e r l i t e r a t u r e (38,39) 51 examining c a r d i a c dynamics d u r i n g submaximal and maximal e x e r c i s e . R e s u l t s o f Maximal Oxygen P u l s e Data T a b l e 16 shows the means and s t a n d a r d d e v i a t i o n s f o r maximal oxygen p u l s e f o r a l l t h r e e p i e c e s o f equipment, as w e l l as the F v a l u e o b t a i n e d from the ANOVA d a t a . See Appendix C f o r e x a m i n a t i o n o f the complete ANOVA t a b l e . F i g u r e 12 g i v e s a g r a p h i c r e p r e s e n t a t i o n o f t h e d a t a from T a b l e 16 TABLE 16 MAXIMAL OXYGEN PULSE (ML/BEAT) (MEANS, STANDARD DEVIATIONS AND F VALUES) Mean SD D y n a v i t 18.16 2.04 Monark 17.55 2.33 T r e a d m i l l 18.09 2.56 F Value 0.98 The p r e c e e d i n g r e s u l t s i n d i c a t e t h a t t h e r e was no s i g n i f i c a n t d i f f e r e n c e i n maximal oxygen p u l s e among a l l t h r e e p i e c e s o f equipment, as s u p p o r t e d by a n o n - s i g n i f i c a n t F v a l u e o f 0.98 (the p r o b a b i l i t y t h a t F was exceeded was .3912). D i s c u s s i o n o f Maximal Oxygen P u l s e R e s u l t s As p r e v i o u s l y s t a t e d , oxygen p u l s e was not a c e n t r a l a s p e c t o f t h i s t h e s i s , but a s t a t i s t i c a l a n a l y s i s o f maximal oxygen p u l s e was done t o c l a r i f y any p o s s i b l e d i f f e r e n c e s between the two b i k e s . The F v a l u e o f 0.98 i n d i c a t e d Monark T r e a d m i l l D y n a v i t FIGURE 12 MAXIMAL OXYGEN PULSE (ML/BEAT) (MEANS AND STANDARD DEVIATIONS) 53 t h a t t h e r e was no d i f f e r e n c e i n maximal oxygen p u l s e among a l l t h r e e p i e c e s o f equipment. S t u d i e s which have examined t h i s p a r t i c u l a r p h y s i o l o g i c a l parameter g e n e r a l l y r e p o r t a lower maximal oxygen p u l s e v a l u e on the b i c y c l e than on the t r e a d m i l l , a f i n d i n g which i s not s u p p o r t e d by t h i s s t u d y (38,39, 45). Some s t u d i e s s u g g e s t t h a t above a c e r t a i n c r i t i c a l h e a r t r a t e i n maximal b i c y c l e e x e r c i s e , t h e r e i s a drop i n s t r o k e volume due t o a d e c r e a s e i n d i a s t o l i c f i l l i n g time and/or a d e c r e a s e d venous r e t u r n . The r e d u c t i o n i n s t r o k e volume would be r e f l e c t e d by a reduced c a r d i a c o u t p u t , a d e c r e a s e i n oxygen uptake and thus a lower oxygen p u l s e d u r i n g c y c l i n g . The u n u s u a l l y h i g h maximal h e a r t r a t e s a c h i e v e d on t h e t r e a d m i l l i n t h i s s t u d y may have e f f e c t i v e l y r e s u l t e d i n a lower v a l u e f o r maximal oxygen p u l s e than i s u s u a l l y found when t r e a d m i l l and c y c l i n g v a l u e s a r e compared. One p o s s i b l e e x p l a n a t i o n f o r the u n u s u a l l y h i g h maximal h e a r t r a t e s i n t h i s study i s t h a t most o f the s u b j e c t s were u n f a m i l i a r w i t h t r e a d m i l l r u n n i n g . On the b i c y c l e ergometers t h e y may have f e l t more i n c o n t r o l o f a r r i v i n g a t t h e i r e x e r c i s e e n d p o i n t , whereas u n f a m i l i a r i t y w i t h the t r e a d m i l l may have r e s u l t e d i n t h e i r b e i n g pushed beyond t h e i r normal p s y c h o l o g i c a l and p h y s i o l o g i c a l l i m i t s . R e s u l t s and D i s c u s s i o n o f the S u b j e c t i v e Response Q u e s t i o n a i r e T a b l e 17 shows the d i s t r i b u t i o n o f r e s p o n s e s from a l l s u b j e c t s when asked t o e x p l a i n t h e i r r e a s o n s f o r d i s c o n t i n u i n g each t e s t . A l t h o u g h some s l i g h t d i f f e r e n c e s were not e d , 92.3% o f the s u b j e c t s responded t h a t the D y n a v i t and Monark b i c y c l e t e s t s r e s u l t e d i n l e g f a t i g u e o r extreme l e g p a i n , c a u s i n g c e s s a t i o n o f e x e r c i s e . Of the t h i r t e e n s u b j e c t s , 69.2% s t a t e d t h a t c a r d i o - r e s p i r a t o r y f a t i g u e was the cause o f t e r m i n a t i o n o f the t r e a d m i l l e x e r c i s e , w h i l e 15.4% s a i d t h a t l e g f a t i g u e was the cause. Another 15.4% s t a t e d t h a t t h e y c o u l d not t r u l y d i f f e r e n t i a t e between l e g f a t i g u e and c a r d i o - r e s p i r a t o r y e x h a u s t i o n on the t r e a d m i l l , but the i n d i c a t -i o n was t h a t a g e n e r a l f a t i g u e was the cause. One s u b j e c t s t a t e d t h a t he d i s c o n t i n u e d the Monark b i c y c l e t e s t due t o c a r d i o - r e s p i r a t o r y f a t i g u e , and a n o t h e r s t a t e d t h a t he c o u l d not d i f f e r e n t i a t e between l e g and c a r d i o -r e s p i r a t o r y f a t i g u e on the D y n a v i t t e s t . TABLE 17 SUBJECTIVE RESPONSE QUESTIONAIRE DISTRIBUTION OF RESPONSES:' REASONS FOR DISCONTINUING THE TESTS C a r d i o - R e s p i r a t o r y F a t i g u e Leg F a t i g u e U n d i f f e r e n t i a t e d S u b j e c t 1. DD T D,M 2. BF1 T D,M 3. BF2 T D,M 4. CH D,M T 5. MH T,D,M 6. DL T,D,M 7. BA T D,M 8. ML T D,M 9. RB D,M T 10. PV T,M D 11. WK T D,M 12. RW T M D 13. MC T D,M T = T r e a d m i l l D = D y n a v i t M = Monark / These r e s u l t s a r e i n keeping w i t h t he m a j o r i t y o f r e p o r t s i n the l i t e r a t u r e which i n d i c a t e t h a t maximal b i c y c l e e x e r c i s e c auses extreme l e g p a i n and f a t i g u e , f o r c i n g t he t e r m i n a t i o n o f e x e r c i s e . A study by P a n d o l f 55 and Noble (63) o n . r a t i n g s o f p e r c e i v e d e x e r t i o n ,(RPE) on the b i c y c l e ergometer, s u g g e s t e d - t h a t l o c a l m u s c u l a r s e n s a t i o n s such as m u s c u l a r f o r c e , and m u s c u l a r and j o i n t d i s c o m f o r t may be i m p o r t a n t f a c t o r s i n the RPE a t v a r i o u s p e d a l l i n g s p e e d s , e s p e c i a l l y a t higher-power o u t p u t s . " P r o p r i o c e p t i v e muscle and tendon s e n s a t i o n s a r e c o n c e r n e d w i t h c o n t r a c t i l e l e n g t h s o f muscle and the amount o f t e n s i o n on the muscles and tendons." ( 6 3 ) . I t i s p o s s i b l e t h a t t h e s e s e n s a t i o n s may cause a s h a r p i n c r e a s e i n the RPE a t h i g h power o u t p u t s , thus c o n t r i b u t i n g a p s y c h o l o g i c a l element to the premature c e s s a t i o n o f e x e r c i s e i n m a x i m a l - c y c l i n g . , The p r e s e n t f i n d i n g s were.somewhat confounded, however, by the l a r g e d i f f e r e n c e i n t o t a l work time means between the b i c y c l e t e s t s and the t r e a d m i l l t e s t s . A s i d e from the n a t u r e o f the c y c l i n g e x e r c i s e , the l o n g e r d u r a t i o n o f the b i c y c l e t e s t s may have c o n t r i b u t e d t o the premature o n s e t o f l e g muscle f a t i g u e , as w e l l as to the s u b j e c t s ' p e r c e p t i o n o f the n a t u r e o f the f a t i g u e . Thus d u r a t i o n o f the t e s t may be t o some degree confounded w i t h the n a t u r e o f t h e t e s t i n d i s t i n g u i s h i n g the s u b j e c t s ' s u b j e c t i v e r e s ponse t o maximal work. General D i s c u s s i o n F i n d i n g s d e s c r i b e d i n the 'Results.' and ' D i s c u s s i o n ' s e c t i o n s i n d i c a t e t h a t the main hypotheses o r i g i n a l l y s t a t e d i n t h i s s t u d y were no t s u b s t a n t -i a t e d . No d i f f e r e n c e s were found between t h e Monark and D y n a v i t ergometers i n peak oxygen consumption o r t o t a l work t i m e , nor were.any d i f f e r e n c e s n o ted i n submaximal h e a r t r a t e o r submaximal oxygen uptake. A l t h o u g h n o t c e n t r a l a s p e c t s of..the t h e s i s , submaximal oxygen p u l s e , maximal oxygen p u l s e , and maximal:heart r a t e were examined, and no d i f f e r e n c e s were found. A s u b j e c t i v e r e sponse q u e s t i o n a i r e was a l s o i n c l u d e d i n the s t u d y , and i n d i c a t e d 56 t h a t both the D y n a v i t and Monark ergometers produced extreme Teg p a i n and f a t i g u e , which n e c e s s i t a t e d the t e r m i n a t i o n o f e x e r c i s e . Only the t r e a d m i l l appeared t o c o n s i s t e n t l y produce what was f e l t t o be an o v e r a l l o r c a r d i o -r e s p i r a t o r y f a t i g u e . The t r e a d m i l l a l s o e l i c i t e d the h i g h e s t peak oxygen consumption v a l u e s o f the t h r e e p i e c e s o f equipment. D i s c u s s i o n o f R e l a t e d L i t e r a t u r e A comparison o f t h i s s t u d y t o t h a t done by E d i n g t o n (.24) produces s h a r p c o n t r a s t s i n t h e . r e s u l t s . H i s f i n d i n g s i n d i c a t e d t h a t t h e . D y n a v i t ergometer was l e s s s t r e s s f u l t o use t h a n . t h e Monark, as i l l u s t r a t e d by l e s s p e r c e i v e d e x e r t i o n , l e s s peak f o r c e r e q u i r e d to p e d a l , l e s s peak EMG a c t i v i t y , l e s s g l y c o g e n u t i l i z a t i o n , l e s s oxygen consumption, l e s s p e r c e n t a g e o f maximum h e a r t r a t e , l e s s v a r i a t i o n i n . p e d a l v e l o c i t y and l e s s peak a c c e l e r a t i o n r e q u i r e d a t the h i p . However, the one a p p a r e n t f l a w i n . E d i n g t o n ' s s t u d y c oncerned the c a l i b r a t i o n p r o c e s s , as o u t l i n e d i n C h a p t e r I I . I f the Monark's 9% c o r r e c t i o n f a c t o r f o r . f r i c t i o n l o s s e s was n o t taken i n t o a c c o u n t then the r e s u l t s o f the s t u d y become v e r y much i n doubt, a s . t h e s u b j e c t s , when r i d i n g the Monark ergometer, would e f f e c t i v e l y be w o r k i n g a t a 9% h i g h e r energy o u t p u t than r e c o r d e d . The p r e s e n t s t u d y i n d i c a t e s t h a t u p h i l l r u n n i n g on the t r e a d m i l l r e s u l t s i n h i g h e r peak oxygen consumption v a l u e s ( o r maximal oxygen uptake) than e i t h e r o f -the b i c y c l e e r g o m e t e r s , but the reasons b e h i n d t h i s f i n d i n g a r e n o t c l e a r . , I t i s the b e l i e f o f the a u t h o r t h a t s e v e r a l f a c t o r s may be i n v o l v e d , i n c l u d i n g a. h i g h e r a c t i v e muscle mass during, t r e a d m i l l e x e r c i s e , c o u p l e d w i t h a g r e a t e r peak f o r c e a p p l i c a t i o n r e q u i r e m e n t d u r i n g c y c l i n g . The s u g g e s t i o n t h a t c y c l i n g causes g r e a t e r i n t r a m u s c u l a r c o n s t r i c t i o n o f b l o o d f l o w i n the Tegs than does r u n n i n g (.due to the h i g h peak f o r c e 57 r e q u i r e m e n t ) , seems t o be the m o s t - l o g i c a l c o n t r i b u t i n g f a c t o r t o the o n s e t o f f a t i g u e i n maximal b i c y c l e e x e r c i s e . There i s no d i r e c t e v i d e n c e however, t o s u p p o r t t h i s c o n t e n t i o n . The s t u d y b y L a v o i e (52) i n d i c a t e d t h a t the use o f r a c i n g s t i r r u p s on a Monark ergometer p r o d u c e d maximal oxygen uptake>values n o t s i g n i f i c a n t l y d i f f e r e n t from t r e a d m i l l - s c o r e s . It-was h i s c o n t e n t i o n t h a t the r a c i n g s t i r r u p s e n a b l e d the s u b j e c t s t o i n c r e a s e the amount o f a c t i v e muscle mass. However, i t s h o u l d be n o t e d t h a t a l l o f h i s s u b j e c t s were e i t h e r r e c r e a t i o n a l o r c o m p e t i t i v e c y c l i s t s . - I t i s p r o b a b l e t h a t the s p e c i f i c a l l y t r a i n e d l o c a l muscle mass o f t h e s e s u b j e c t s e n a b l e d them t o a c h i e v e a g r e a t e r t a x i n g o f the c a r d i o - r e s p i r a t o r y system, and thus h i g h e r maximal oxygen uptake s c o r e s than n o n - c y c l i s t s . T h i s s u g g e s t i o n i s s u p p o r t e d by T h i a r t and BTaauw ( 7 5 ) , who found t h a t t r a i n e d c y c l i s t s a c h i e v e d maximal oxygen uptake v a l u e s as h i g h o r even h i g h e r . t h a n t h o s e o b t a i n e d on the t r e a d m i l l . I t would appear t h a t a r e d u c t i o n i n peak f o r c e a p p l i c a t i o n d u r i n g c y c l i n g i s n o t as i m p o r t a n t i n the d e t e r m i n a t i o n o f peak- oxygen consumption as i s the e f f e c t o f s p e c i f i c i t y o f t r a i n i n g . I t i s c l e a r from the r e s u l t s o f t h i s s t u d y t h a t t h e r e i s no d i f f e r e n c e i n the p h y s i o l o g i c a l r e s p o n s e t o e x e r c i s e , between an e l e c t r o n i c a l l y i braked, D y n a v i t b i c y c l e ergometer and a m e c h a n i c a l l y b r a k e d , Monark b i c y c l e ergometer. Thus the c o n t e n t i o n t h a t the l o a d i n g system o f t h e D y n a v i t ergometer reduces l e g muscle f a t i g u e appears to be unfounded. T h i s c o n c l u s i o n i s . s u p p o r t e d by MacLeod (.53). who found t h a t premature l e g f a t i g u e r e s u l t e d i n the c e s s a t i o n o f D y n a v i t b i c y c l e e x e r c i s e b e f o r e the c a r d i o -r e s p i r a t o r y system became f u l l y t a x e d . 58 A p p l i c a t i o n o f the R e s u l t s One u s e f u l a p p l i c a t i o n o f the r e s u l t s o f t h i s s t u d y i n v o l v e s the use o f the D y n a v i t ergometer f o r submaximal e x e r c i s e t e s t i n g . A l t h o u g h s e v e r a l p r o t o c o l s a r e used d u r i n g c o n v e n t i o n a l D y n a v i t t e s t i n g , ( 4 0 ) , the p r e s e n t f i n d i n g s open new avenues f o r D y n a v i t submaximal. t e s t i n g . S i n c e t h e r e appears t o be.no d i f f e r e n c e i n the p h y s i o l o g i c a l r e s p o n s e s t o submaximal e x e r c i s e between the two b i c y c l e s , i t f o l l o w s t h a t the D y n a v i t c o u l d be used t o complete such p r e d i c t i v e a e r o b i c c a p a c i t y t e s t s as the Astrand-Ryhming P r e d i c t e d Oxygen Uptake T e s t o r the M o d i f i e d S j o s t r a n d PWC T e s t . . A c o r r e c t i o n f a c t o r o f a p p r o x i m a t e l y 9% would have t o be added t o . t h e D y n a v i t h e a r t r a t e r e s p o n s e s t o equate those r e s u l t s to the A s t r a n d o r S j o s t r a n d norms. Such a c o r r e c t i o n f a c t o r would be s i m i l a r to t h a t employed by A s t r a n d i n the d e t e r m i n a t i o n o f h i s n o r m a t i v e s t a n d a r d s f o r t h e Astrand-Ryhming T e s t ( 7 ) . U n f o r t u n a t e l y a c o r r e c t i o n f a c t o r cannot be d i r e c t l y a p p l i e d t o the work-l o a d s e t t i n g o f t h e D y n a v i t model used i n t h i s s t u d y , as i t s workload increments o f 10 watts a r e n o t . s m a l l enough t o a l l o w f o r a c c u r a t e e q u a l -i z a t i o n o f the D y n a v i t l o a d s e t t i n g t o t h a t o f the a p p r o p r i a t e Monark s e t t i n g . L i m i t a t i o n s o f t h e D y n a v i t Ergometer A major l i m i t a t i o n which a r i s e s from the p r e s e n t s t u d y i s the c a l i b r a t -i o n o f the D y n a v i t b i c y c l e ergometer. The c o m p l e x i t y o f the c a l i b r a t i o n p r o c e s s n e c e s s i t a t e s one. o f t h r e e a l t e r n a t i v e s a t p r e s e n t ; e x p e n s i v e c a l i b r a t i o n equipment may be d e s i g n e d and b u i l t on s i t e , t h e ergometer may be r e t u r n e d to the m a n u f a c t u r i n g c e n t e r i n I l l i n o i s f o r c a l i b r a t i o n by f a c t o r y t e c h n i c i a n s , o r a D y n a v i t t e c h n i c i a n c o u l d p o s s i b l y t r a v e l t o y o u r t e s t i n g s i t e t o complete the c a l i b r a t i o n . None o f t h e s e a l t e r n a t i v e s i s 59 v e r y s a t i s f a c t o r y t o the p r a c t i t i o n e r . The D y n a v i t ergometer used i n t h i s s t u d y had a maximal w o r k l o a d s e t t i n g o f 300 w a t t s . T h i s i s more t h a n adequate f o r submaximal t e s t i n g but n o t f o r t e s t s o f a maximal nature.. Two r e l a t i v e l y u n t r a i n e d s u b j e c t s i n the p r e s e n t s t u d y a c h i e v e d and m a i n t a i n e d the h i g h e s t - D y n a v i t w o r k l o a d s e t t i n g , and so had to be e x c l u d e d from the f i n a l a n a l y z e s . I t was a l s o found t h a t the D y n a v i t s e a t h e i g h t adjustment was b a r e l y adequate f o r t h e t a l l e r and/or l o n g - l e g g e d s u b j e c t s i n t h i s s t u d y . T h i s c o u l d c r e a t e a p o t e n t i a l l i m i t a t i o n o f the ergometer f o r e s t a b l i s h i n g p r o p e r l e g l e n g t h s e t t i n g s i n . s u b j e c t s w i t h l e g s g r e a t e r , than 100 cm i n length., as measured i n t h i s s t u d y . » A s s o c i a t e d w i t h the v e r t i c a l p o s i t i o n i n g o f the s e a t i s i t s h o r i z o n t a l placement. A c c o r d i n g t o A s t r a n d (8) the s u b j e c t s h o u l d be s i t t i n g a l m o s t v e r t i c a l l y o v e r the p e d a l s , which i s the case w i t h the Monark ergometer. However, the D y n a v i t s e a t i s s i t u a t e d a p p r o x i m a t e l y 2 t o 3 i n c h e s f u r t h e r back than the Monark s e a t , i n r e l a t i o n t o a v e r t i c a l p o s i t i o n o v e r t h e p e d a l s . A l t h o u g h i t i s . u n l i k e l y t h a t . t h i s s l i g h t d i s p l a c e m e n t o f t h e D y n a v i t s e a t would s i g n i f i c a n t l y 1 i n f l u e n c e the r e s u l t s o f the p r e s e n t s t u d y , the p o s s i b i l i t y o f a d i f f e r e n c e i n the b i b m e c h a n i c a l a p p l i c a t i o n o f f o r c e i s i n c r e a s e d . CHAPTER V SUMMARY AND CONCLUSIONS Summary The purpose o f t h i s i n v e s t i g a t i o n was t o compare an e l e c t r o n i c a l l y b r aked, D y n a v i t b i c y c l e ergometer t o a m e c h a n i c a l l y b raked, Monark b i c y c l e ergometer, and i n so d o i n g t o examine s e l e c t e d p o t e n t i a l d i f f e r e n c e s i n the p h y s i o l o g i c a l r e sponse t o e x e r c i s e s t r e s s which may have been e l i c i t e d by the l o a d i n g systems unique t o each a p p a r a t u s . The main problem was t o d etermine i f t h e r e were d i f f e r e n c e s i n t o t a l work time v a l u e s between the two b i c y c l e s , and t o see i f t h e s e p o s s i b l e d i f f e r e n c e s were c o r r o b o r a t e d by c o r r e s p o n d i n g d i f f e r e n c e s i n peak oxygen consumption. The s u b s i d i a r y problems i n v e s t i g a t e d p o s s i b l e d i f f e r e n c e s i n submaximal h e a r t r a t e and oxygen uptake. The s t u d y c o n s i s t e d o f t h e c o m p l e t i o n by a l l t h i r t e e n s u b j e c t s o f one maximal e x e r c i s e bout on each o f t h r e e p i e c e s o f t e s t i n g equipment; the t r e a d m i l l , the D y n a v i t ergometer, and the Monark ergometer. D u r i n g each e x e r c i s e t e s t , e x p e r i m e n t a l v a l u e s o f submaximal h e a r t r a t e , submaximal oxygen uptake, peak oxygen consumption and t o t a l work time were r e c o r d e d , and the f o l l o w i n g r e s u l t s were then d e t e r m i n e d . There was no s t a t i s t i c a l d i f f e r e n c e found between the two b i c y c l e s i n terms o f peak oxygen consumption, w h i l e the t r e a d m i l l e l i c i t e d t he h i g h e s t v a l u e s . T o t a l work time was not s t a t i s t i c a l l y d i f f e r e n t between the two b i c y c l e e r g o m e t e r s , and no d i f f e r e n c e was found i n submaximal h e a r t r a t e o r oxygen uptake r e s p o n s e s . S e v e r a l o t h e r f a c t o r s were a l s o examined, a l t h o u g h t h e y were not c e n t r a l hypotheses o f the study. These i n c l u d e d maximal h e a r t r a t e , submaximal oxygen p u l s e , maximal oxygen p u l s e , and s u b j e c t i v e r e sponse t o e x e r c i s e . A g a i n , no d i f f e r e n c e was found between the two b i c y c l e s i n any o f t h e s e v a r i a b l e s . 60 61 C o n c l u s i o n s The r e s u l t s o f the p r e s e n t s t u d y i n d i c a t e t h a t the f o l l o w i n g c o n c l u s i o n s a r e j u s t i f i e d : 1. Maximal e x e r c i s e t e s t s performed on e i t h e r the Monark o r D y n a v i t b i c y c l e ergometers produced peak oxygen consumption v a l u e s which d i d not d i f f e r s t a t i s t i c a l l y . 2. There was no d i f f e r e n c e i n t o t a l work time between the D y n a v i t and Monark ergometers, s u g g e s t i n g t h a t the n a t u r e o f the work performed on each b i c y c l e d i d not d i f f e r g r e a t l y . 3. T r e a d m i l l v a l u e s f o r peak oxygen consumption were h i g h e r than t h o s e o b t a i n e d on the Monark o r D y n a v i t e r g o m e t e r s . 4. There was no d i f f e r e n c e i n submaximal oxygen uptake between the two b i c y c l e ergometers. 5. Submaximal h e a r t r a t e d i d not d i f f e r s t a t i s t i c a l l y between the two b i c y c l e ergometers. 6. No d i f f e r e n c e s were found between t h e two b i c y c l e s i n submaximal oxygen p u l s e , maximal oxygen p u l s e , o r maximal h e a r t r a t e . 7. No a p p a r e n t d i f f e r e n c e s were found between the Monark and D y n a v i t ergometers i n the p a r t i c i p a n t s s u b j e c t i v e r e s p o n s e t o e x e r c i s e s t r e s s . 8. The above r e s u l t s i n d i c a t e t h a t any supposed d i f f e r e n c e s i n the l o a d i n g systems o f the two b i c y c l e ergometers were not s u b s t a n t i a t e d by the p h y s i o l o g i c a l r e s p o n s e s o f the t e s t s u b j e c t s t o e x e r c i s e . Recommendations A. Recommendations A r i s i n g from the Study The r e s u l t s o f the p r e s e n t s t u d y i n d i c a t e t h a t t h e D y n a v i t ergometer produces p h y s i o l o g i c a l r e s p o n s e s t o e x e r c i s e s t r e s s which do not d i f f e r from 62 t h a t o f the Monark. I t i s recommended t h a t the D y n a v i t c o u l d be used f o r submaximal t e s t s such as the Astrand-Ryhming P r e d i c t e d Oxygen Uptake T e s t o r the M o d i f i e d S j o s t r a n d PWC T e s t . In keeping w i t h the f i n d i n g s o f C a r r o l l (15) and Hockey (40) i t i s suggested t h a t i n t h e s e and o t h e r t e s t s the p e d a l l i n g f r e q u e n c y be h e l d c o n s t a n t , even though the D y n a v i t i s supposed t o m a i n t a i n a c o n s t a n t workload r e g a r d l e s s o f small changes i n rpm. A f u r t h e r study t o examine whether small changes i n p e d a l l i n g f r e q u e n c y o f the D y n a v i t b i c y c l e produce d i f f e r e n c e s i n oxygen uptake, h e a r t r a t e , e t c . , would seem t o be worth d o i n g . T h i s recommendation i s based on a s t u d y by C a r r o l l (15) who found t h a t the Elema-Schonander c o n s t a n t workload b i c y c l e ergometer e l i c i t e d d i f f e r e n t s t e a d y s t a t e h e a r t r a t e and r e s p i r a t o r y r a t e r e s p o n s e s a t d i f f e r e n t p e d a l l i n g r a t e s , even though t h e s e p e d a l l i n g f r e q u e n c i e s were w i t h i n the p r e s c r i b e d a c c u r a c y l i m i t s o f the b i c y c l e . To improve t h i s s t u d y , a c t u a l measurements o f f o r c e a p p l i c a t i o n d u r i n g c y c l i n g (such as t h o s e c a r r i e d out by E d i n g t o n ) would be recommended. These t e c h n i q u e s were u n f o r t u n a t e l y beyond the scope o f t h e p r e s e n t study. B. Recommendations t o the M a n u f a c t u r e r A p p r o p r i a t e c a l i b r a t i o n equipment s h o u l d be made a v a i l a b l e t o the l o c a l d i s t r i b u t o r s o f the D y n a v i t b i c y c l e ergometer. T h i s would e n a b l e the p r a c t i t i o n e r t o c a l i b r a t e the ergometer on a r e g u l a r b a s i s (two t o t h r e e t i m e s each y e a r minimum), and t h u s a c h i e v e c o n s i s t e n t and a c c u r a t e d a t a . The v a l i d i t y o f the p r e s e n t s t u d y would have been e s t a b l i s h e d on more c e r t a i n grounds i f l o c a l c a l i b r a t i o n c o u l d have been c a r r i e d out b e f o r e and a f t e r t he t e s t i n g p e r i o d . C e r t a i n a s p e c t s o f t h i s study suggest t h a t a w i d e r range o f D y n a v i t workload s e t t i n g s ( i e : up t o 400-500 w a t t s ) would be d e s i r a b l e f o r maximal t e s t i n g c a p a b i l i t i e s , and i t i s a recommendation o f t h i s s t u d y f o r the 63 m a n u f a c t u r e r s t h a t machines o f t h i s c a p a b i l i t y be made a v a i l a b l e f o r purchase by r e s e a r c h l a b o r a t o r i e s . I t i s recommended t h a t t he adjustment range f o r s e a t h e i g h t on the D y n a v i t ergometer be i n c r e a s e d , t o a l l o w f o r a p p r o p r i a t e l e g l e n g t h s e t t i n g i n the case o f l o n g - l e g g e d s u b j e c t s . For purposes o f t e s t i n g a p p a r a t u s s t a n d a r d i z a t i o n , i t i s recommended t h a t the h o r i z o n t a l placement o f the D y n a v i t s e a t be a d j u s t e d f o r w a r d t o c o r r e s p o n d w i t h t he Monark s e a t placement, and thu s t o be more v e r t i c a l l y o ver the p e d a l s , as recommended by A s t r a n d (8). REFERENCES 64 65 1. American C o l l e g e o f S p o r t s M e d i c i n e . G u i d e l i n e s f o r Graded E x e r c i s e T e s t i n g and E x e r c i s e P r e s c r i p t i o n . P h i l a d e l p h i a : Lea and F e b i g e r , 1976. 2. American C o l l e g e o f S p o r t s M e d i c i n e . "The Recommended Q u a n t i t y and Q u a l i t y o f E x e r c i s e f o r D e v e l o p i n g and M a i n t a i n i n g F i t n e s s i n H e a l t h y A d u l t s . " Med. S c i . S p o r t s , 1 3 ( 3 ) : 3 , 1978. 3. Asmussen, E. " P o s i t i v e and N e g a t i v e M u s c u l a r Work." A c t a phys. 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Blaauw. "The VTL Max and the A c t i v e Muscle Mass." South A f r i c a n J o u r n a l f o r Research i n S p o r t , P h y s i c a l E d u c a t i o n and  R e c r e a t i o n . P r o c e e d i n g s o f the I n t e r n a t i o n a l Committee on P h y s i c a l F i t n e s s R esearch. ( P a r t 1 ) . Johannesburg, 17-19 J u l y , 1978. 2 ( 1 ) : 13-17, 1979. 76. von Dobeln, W. "A Simple B i c y c l e Ergometer." J . A p p l . P h y s i o l . , 7: 2 22-224, 1954. 77. Wyndham, C.H., e t a l . " S t u d i e s o f Maximum C a p a c i t y o f Men f o r P h y s i c a l E f f o r t . " A r b e i t s p h y s i o l . , 22:285-295, 1966. APPENDICES 71 APPENDIX A SUBJECTIVE RESPONSE QUESTIONAIRE "72 73 SUBJECTIVE RESPONSE QUESTIONAIRE-T e s t was d i s c o n t i n u e d due t o : 1. Leg s o r e n e s s and/or l e g muscle f a t i g u e . 2. B r e a t h l e s s n e s s , nausea, d i z z i n e s s , e t c . ( c a r d i o - r e s p i r a t o r y f a t i g u e ) . 3. Unable t o d i f f e r e n t i a t e . 4. Other r e a s o n s : ( C i r c l e t h e a p p r o p r i a t e answer) D y n a v i t : 1 2 3 4 - ( e x p l a i n ) Monark: 1 2 3 4 - ( e x p l a i n ) T r e a d m i l l : 1 2 3 4 - ( e x p l a i n ) 5. Was t h e r e any d i f f e r e n c e between the two b i c y c l e ergometers i n the i n d i v i d u a l ' s s u b j e c t i v e r e s ponse t o each e x e r c i s e t e s t ? Yes: No: I f y e s , e x p l a i n the d i f f e r e n c e ( s ) : 6. Was t h e r e any d i f f e r e n c e between the b i c y c l e ergometers and the t r e a d m i l l i n the i n d i v i d u a l ' s s u b j e c t i v e r e s p o n s e t o each e x e r c i s e t e s t ? Yes:_ No: I f y e s , e x p l a i n t he d i f f e r e n c e ( s ) : APPENDIX 3 RAW DATA 74 PEAK OXYGEN CONSUMPTION AND TOTAL WORK TIME  D y n a v i t Monark T r e a d m i l l S u b j e c t s DD POC 46.92 44.10 53.59 TWT 18:00 19:05 13:58 B F l POC 40.53 41.65 42.90 TWT 16:11 15:32 06:16 BF2 POC 37.22 26.29 45.09 TWT 16:30 17:02 08:04 CH POC 46.17 45.89 48.57 TWT 14:39 15:03 09:10 MH POC 45.72 41.57 41.56 TWT 15:30 15:05 08:15 DL POC 46.90 47.29 52.89 TWT 16:15 14:41 10:41 BA POC 50.06 48.23 58.20 TWT 17:01 18:47 14:18 ML POC 50.61 49.35 51.66 TWT 14:05 15:08 10:04 RB POC 56.29 52.90 55.28 TWT 15:59 16:03 12:45 PV POC 50.84 47.87 52.48 TWT 13:37 14:09 10:34 WK POC 41.18 46.38 47.23 TWT 15:28 16:27 10:12 RW POC 56.12 56.37 51.33 TWT 15:09 15:13 09:55 MC POC 40.67 44.50 47.22 TWT 14:58 15:20 08:30 POC = Peak Oxygen Consumption (ml/kg/min) TWT = T o t a l Work Time (m i n u t e s / s e c o n d s ) MAXIMAL HEART RATE AND MAXIMAL OXYGEN PULSE D y n a v i t Monark T r e a d m i l l S u b j e c t s DD MHR 190 185 200 MOP 21.90 21.91 21.35 BF1 MHR 206 195 212 MOP 17.23 17.32 18.54 BF2 MHR 200 197 205 MOP 16.71 13.72 18.10 CH MHR " 193 190 184 MOP 16.84 18.37 19.34 MH MHR 177 175 192 MOP 17.68 18.86 17.60 DL MHR 205 190 210 MOP 18.24 16.74 17.10 BA MHR 190 180 195 MOP 22.59 21.39 21.69 ML MHR 215 215 220 MOP 18.05 15.44 16.18 RB MHR 195 190 216 MOP 19.46 18.67 21.11 PV MHR 202 190 208 MOP 15.45 15.11 13.41 WK MHR 208 212 216 MOP 17.12 16.18 . 18.84 RW MHR 195 200 205 MOP 17.64 17.20 14.00 MC MHR •: 190 189 195 MOP 17.21 17.27 17.90 MHR = Maximal Heart Rate (bpm) MOP = Maximal Oxygen P u l s e (ml/beat) SUBMAXIMAL OXYGEN PULSE D y n a v i t min.1 min.2 min.3 min.4 mi n.5 min.6 min.7 S u b j e c t s ' DD 10. 64 09. 90 11. 30 14. 44 14. 17 14.25 15. 23 B F l 08. 17 08. 27 09. 53 10. 33 12. 23 10.52 11. 29 BF2 08. 62 08. 92 08. 07 07. 15 09. 48 10.64 12. 52 CH 14. 47 10. 22 12. 27 11. 18 14. 21 10.97 14. 96 MH 08. 73 09. 73 08. 84 09. 83 12. 00 09.84 12. 07 DL 07. 46 10. 73 06. 17 09. 85 10. 15 11.00 11. 29 BA 08. 69 08. 93 08. 90 09. 52 12. 44 14.61 14. 46 ML 07. 78 08. 61 09. 76 11. 26 10. 00 10.19 11. 33 RB 12. 00 09. 60 08. 95 07. 04 11. 92 12.75 14. 37 PV 08. 64 08. 56 07. 82 09. 27 09. 35 09.93 12. 73 WK 08. 25 06. 16 06. 39 08. 62 10. 50 10.20 11. 30 RW 07. 67 08. 44 09. 46 07. 17 11. 12 13.86 11. 17 MC 06. 45 09. 65 08. 36 06. 02 09. 36 14.54 11. 71 *Submaximal Oxygen P u l s e (ml/beat) Monark mir i . l min.2 mir i.3 min. 4 mir 1.5 mir i.6 min. 7 07. 60 09.58 14. 79 09. 26 12. 41 13. 18 13. 67 07. 59 09.73 09. 27 10. 99 10. 38 12. 15 12. 96 09. 01 10.23 08. 50 11. 03 12. 36 13. 01 13. 32 06. 67 09.40 09. 10 09. 64 13. 83 11. 08 12. ,46 08. 53 06.70 07. 67 09. 32 10. 86 10. 15 10. 22 07. 71 06.76 06. 79 08. 15 08. 23 09. 65 10. 58 09. 29 10.00 09. 58 12. 78 13. 15 15. 37 15. 15 10. 00 12,42 07. 46 08. 93 10. 00 10. 14 09. 58 08. 00 08.86 10. 09 09. 24 11. 20 11. 03 14. 62 04. 39 05.97 08. 81 09. 29 09, 20 10. 69 10. 84 07. 81 08.85 07. 22 07. 92 09. 61 09. 59 09. 54 06. 44 08.73 07. 58 07. 72 11. 82 10. 80 11. 93 05. 79 08.17 07. 66 07. 54 11. 04 13. 31 13. 03 1^ , minutes (min.) 1 through 7.* ^ SUBMAXIMAL OXYGEN UPTAKE  D y n a v i t Monark  mi n.1 min.2 min.3 min.4 min.5 min.6 min.7 min.1 mi n.2 min.3 min.4 min.5 min.6 min.7 S u b j e c t s DD 13.67 1-1. 35 13. 31 19. 54 19. 07 20. 12 23. 20 08.19 10. 56 16. 33 11. 29 15. .64 16. 67 18. 78 BF1 10.80 10. 68 11. 95 14. 48 18. 61 16. 49 20. 25 10. 65 13. 63 12. 54 17. 92 16.88 19. 64 21. 74 BF2 11.77 12. 21 1.1. 51 09. 73 13. 55 15. 82 20. 66 09. 76 11. 32 08. 90 13. 13 14. ,95 16. 58 18. 12 CH 17.10 12. 62 14. 91 16. 98 22. 53 17. 25 26. 63 10. 48 14. 18 13. 66 15. 91 23. .82 19. 96 24. 29 MH 13.12 14. 56 12. 35 15. 62 19. 60 17. 00 22. 25 13. 09 10. 27 12. 89 15. 21 17. 73 18. 45 19. 60 DL 10.88 16. 21 09. 49 17. 11 18. 35 20. 57 23. 25 12. 90 10. 79 11. 22 15. 58 15. .87 20. 25 24. 23 BA 09.25 09. 46 11. 19 12. 74 18. 25 21. 58 24. 16 09. 74 12. 05 11. 52 17. 42 18. ,24 21. 39 25. 58 ML 14.16 13. 43 16. 89 21. 13 19. 45 22. 60 26. 12 16. 58 22. 37 13. 25 18. 72 22. 54 22. 16 23. 77 RB . 15.02 13. 26 13. 03 11. 35 20. 03 21. 35 27. 19 13. 17 13. 97 16. 62 16. 26 19. 57 19. 34 28. 37 PV 16.27 16. 03 14.81 20. 11 20. 77 23. 85 33. 75 07. 99 11. 56 17. 67 20. 05 21. 84 26. 43 28. 67 WK 11.85 09. 13 09. 32 14. 41 17. 63 18. 09 22. 07 10. 99 12. 23 11. 07 13. 15 16. 56 18. 67 19. 26 RW 14.65 15. 14 17. 33 14. 17 22. 82 29. 07 . 26. 70 12. 39 16. 81 14. 97" 16. 04 25. 65 24. 46 28. 41 MC 08.58 13. 71 11. 26 07. 81 14. 94 24. 31 20. 79 09. 21 12. 01 11. 93 12. 79 18. 11 22. 49 25. 15 *Submaximal Oxygen Uptake (ml/kg/min), minutes (min.) 1 through 7.* oo SUBMAXIMAL HEART RATE  D y n a v i t Monark min. 1 min. 2 min. 3 min. 4 min. 5 min. 6 min. 7 m i n . l i min. 2 min. 3 min. 4 min. 5 mi n. 6 min. j b j e c t s DD 110 100 100 115 115 120 130 96 96 96 108 108 110 120 B F l 115 110 107 120 130 135 155 112 112 109 131 131 130 135 BF2 130 130 135 130 135 140 155 107 107 111 120 120 132 139 CH 85 90 88 110 114 114 129 105 100 100 110 115 120 130 MH 110 110 103 117 120 127 135 109 109 120 117 117 130 137 DL 110 110 115 130 135 140 155 110 108 112 130 130 142 155 BA 84 84 100 105 115 115 130 84 96 96 108 108 108 132 ML 120 115 125 135 140 160 165 110 120 118 140 150 145 165 RB 90 100 105 115 120 120 135 110 105 110 118 117 117 130 PV 118 118 119 136 139 150 165 107 114 118 127 139 145 155 WK 120 125 122 138 140 148 162 105 104 115 125 129 146 151 RW 116 109 111 120 125 127 145 118 118 120 127 132 138 145 MC 110 115 110 108 125 130 140 107 104 107 . 118 115 . 118 135 *Submaximal Heart Rate (bpm), minutes (min .) 1 through 7.* APPENDIX C ANOVA TABLES FOR MAXIMAL DATA 80 ANOVA TABLE FOR TOTAL WORK TIME 81 Source TWT Sum o f Squares d f Mean Square F Prob. 272.05 2 136.03 92.42 <. F Exceeded 001* * S i g n i f i c a n t a t <.OOl ANOVA TABLE FOR PEAK OXYGEN CONSUMPTION Source POC Sum o f Squares d f Mean Square F Prob. 125.11 2 62.55 5.42 F Exceeded 0014* * S i g n i f i c a n t a t .0014 ANOVA TABLE FOR MAXIMAL HEART RATE Source MHR Sum o f Squares d f Mean Square F Prob. 831.39 2 415.69 13.61 < . F Exceeded 001* * S i g n i f i c a n t a t <.001 ANOVA TABLE FOR MAXIMAL OXYGEN PULSE •Source Sum o f Squares d f Mean Square F Prob. F Exceeded MOP 2.89 2 1.45 .98 .3912 (Non-sig) 

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