UBC Theses and Dissertations

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UBC Theses and Dissertations

Elimination of muscle recoil energy in vertical jumping Montford, Gordon Hugh 1985

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ELIMINATION OF MUSCLE RECOIL ENERGY IN VERTICAL JUMPING by Gordon Hugh M o n t f o r d B.A.Rec and P.E., B.Ed., A c a d i a U n i v e r s i t y , 1980 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION i n THE FACULTY OF GRADUATE STUDIES ( S c h o o l 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 ) 7 8 THE UNIVERSITY OF BR I T I S H COLUMBIA SEPTEMBER 1985 ($\ G o r d o n Hugh M o n t f o r d , 1985 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department The University of British Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 DE-6(3/81) ABSTRACT T h i s i s an e m p i r i c a l s t u d y w h i c h i n v e s t i g a t e s t h e p o s s i b i l i t y o f i s o l a t i n g t h e m u s c l e ' s c o n t r a c t i l e component i n d y n a m i c jump t r a i n i n g e x e r c i s e s . C a v a g n a , e t a l . . ( 1 9 6 8 ) ; Asmussen and B o n d e - P e t e r s e n , ( 1 9 7 4 ) ; Komi and B o s c o , ( 1 9 7 8 ) a r e some o f t h e r e s e a r c h e r s c o n f i r m i n g t h e p r e s e n c e o f e l a s t i c e n e r g y i n l e n g t h e n e d ( s t r e t c h e d ) human m u s c l e . T h i s r e c o i l e n e r g y p r o v i d e s an a d d i t i v e e f f e c t when i n t e g r a t e d w i t h t h e human m u s c l e ' s c o n t r a c t i l e component d u r i n g d y n a m i c m u s c u l a r c o n t r a c t i o n s . Komi and B o s c o ( 1 9 7 8 ) a s s e r t e d t h a t t h e r a t e o f s t r e t c h i n g t h e m u s c l e i m m e d i a t e l y p r i o r t o t h e c o n c e n t r i c c o n t r a c t i o n i s t h e key t o p r o d u c i n g h i g h e r l e v e l s o f r e c o i l e n e r g y . P l y o m e t r i c e x e r c i s e s , s u c h as d e p t h j u m p i n g , e x p l o i t t h i s c h a r a c t e r i s t i c i n jump t r a i n i n g . C a v a g n a , e t a l . ( 1 9 7 1 ) s u g g e s t e d t h a t s p e e d o f s h o r t e n i n g by t h e c o n t r a c t i l e component i s t h e l i m i t i n g f a c t o r i n i n t e g r a t i n g t h i s r e c o i l e n e r g y w i t h t h e c o n c e n t r i c c o n t r a c t i o n . T h i s i d e n t i f i e s t o t h i s r e s e a r c h e r , t h a t by e l i m i n a t i n g r e c o i l e n e r g y and i s o l a t i n g t h e c o n t r a c t i l e component i n jump t r a i n i n g , g r e a t e r l o n g t e r m j u m p i n g i m p r o v e m e n t may be a c h i e v e d more e f f i c i e n t l y o v e r a s h o r t e r t r a i n i n g p e r i o d . To e l i m i n a t e t h e r e c o i l e n e r g y i n a d y n a m i c v e r t i c a l j u m p i n g movement the. e c c e n t r i c c o n t r a c t i o n phase i s s l o w e d by an a b s o r b e n t j u m p i n g / l a n d i n g s u r f a c e . T h r e e t y p e s of v e r t i c a l jumps ( a s q u a t jump, a c o u n t e r m o v e m e n t jump and a i i i d e p t h jump f r o m a 0.40 m h e i g h t ) were p e r f o r m e d by 15 f e m a l e s u b j e c t s on two t y p e s o f j u m p i n g / l a n d i n g s u r f a c e s . A K i s t l e r F o r c e P l a t e i s t h e " n o r m a l " 1 a n d i n g / j u m p i n g s u r f a c e ; a foam pad (0.64 x 0.44 x 0.20 m) p l a c e d upon t h e K i s t l e r F o r c e P l a t e i s t h e " a b s o r b e n t " j u m p i n g / l a n d i n g s u r f a c e . The d a t a c o l l e c t e d c o m p r i s e d : H e i g h t jumped, g e n e r a t e d p o s i t i v e m e c h a n i c a l work, a c c r u e d n e g a t i v e m e c h a n i c a l work, change i n p o s i t i v e m e c h a n i c a l work w i t h r e s p e c t t o t h e s q u a t jump, and h e i g h t o f d r o p f o r e a c h d e p t h jump. T h i s s t u d y f o u n d a s i g n i f i c a n t d i f f e r e n c e a t t h e 0.01 l e v e l b etween a " n o r m a l " and an " a b s o r b e n t " j u m p i n g / l a n d i n g s u r f a c e when p e r f o r m i n g v e r t i c a l . j u m p s . E n hanced m e c h a n i c a l work was o b s e r v e d f o r t h e c o u n t e r m o v e m e n t and d e p t h jumps w i t h r e s p e c t t o t h e s q u a t j u m p . ( t h e b a s e l i n e measure of t h e c o n t r a c t i l e c o m p o n e n t ' s a b i l i t y t o do m e c h a n i c a l w o r k ) . T h i s e n h a n c e d work was a t t r i b u t e d t o t h e r e c o v e r y o f s t o r e d r e c o i l e n e r g y and c o n v e r t e d t o a p e r c e n t a g e o f r e c o v e r e d e c c e n t r i c e n e r g y ( r e d u c e d p o t e n t i a l e n e r g y ) . The " n o r m a l " s u r f a c e showed a r e c o v e r y o f 13.4% and 4.8% f o r t h e c o u n t e r m o v e m e n t ' j u m p and d e p t h j u m p . r e s p e c t i v e l y ; s i m i l a r l y , the- " a b s o r b e n t " s u r f a c e showed r e c o v e r y o f 11.3% and - 0 . 5 % . T h e s e r e s u l t s i n d i c a t e t h a t a h i g h l y a b s o r b e n t j u m p i n g / l a n d i n g s u r f a c e d e g r a d e s t h e r e c o v e r y o f s t o r e d r e c o i l e n e r g y i n d e p t h j u m p i n g ; and can be u s e d t o e l i m i n a t e r e c o i l e n e r g y i n p l y o m e t r i c t r a i n i n g , s p e c i f i c a l l y d e p t h j u m p t r a i n i n g . i v TABLE OF CONTENTS C h a p t e r Page ABSTRACT . . . . . . . . i i L I S T OF TABLES . v i L I S T 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 E x p l a n a t i o n o f t h e S t u d y . . . . . . . . . 3 D e l i m i t a t i o n s . . 3 L i m i t a t i o n s . 3 D e f i n i t i o n o f Terms . . . . . 4 H y p o t h e s i s . . . . . . . 6 I I REVIEW OF LITERATURE 7 R e c o i l E n e r g y . . . . 7 S p e c i f i c i t y o f T r a i n i n g 10 Summary . . . . . . . 10 Aim 11 I I I METHODS AND PROCEDURES . . . . . . . . . . . . 13 I n t r o d u c t i o n . . 13 S u b j e c t s 13 T e s t i n g A p p a r a t u s 15 D a t a C o l l e c t i o n 15 E x p e r i m e n t a l D e s i g n . . . . . . 19 S t a t i s t i c a l T r e a t m e n t 19 V TABLE OF CONTENTS C h a p t e r Page IV RESULTS AND DISCUSSION 21 I n t r o d u c t i o n 21 F o r c e vs Time C u r v e P r o f i l e s o f V e r t i c a l Jumps 22 S t a t i s t i c a l A n a l y s i s o f H e i g h t Jumped . . -26 E c c e n t r i c E n e r g y A n a l y s i s 28 REFERENCES . . . 36 APPENDIX A . . . 40 C o n s e n t t o a B i o m e c h a n i c a l E v a l u a t i o n Form 41 APPENDIX B . . . • 42 S p e c i f i c a t i o n s f o r " A b s o r b e n t " Foam J u m p i n g / L a n d i n g Pad . 43 APPENDIX C 44 I n d i v i d u a l s ' V i t a l S t a t i s t i c s 45 APPENDIX D . 46 S q u a t Jumps ( A l l T r i a l s , "no" mat) . . . . 47 S q u a t Jumps ( A l l T r i a l s , " w i t h " mat) . . . 48 Counte r m o v e m e n t Jumps ( A l l T r i a l s , "no" mat) , 49 Co u n t e r m o v e m e n t Jumps ( A l l T r i a l s , " w i t h " mat) 50 D e p t h Jumps ( A l l T r i a l s , "no" mat) . . . . 51 D e p t h Jumps ( A l l T r i a l s , " w i t h " mat) . . . 52 APPENDIX E' . . . . 53 S q u a t Jumps ( A v e r a g e d T r i a l s ) . . . . . . 54 Co u n t e r m o v e m e n t Jumps ( A v e r a g e d T r i a l s ) . . . . . . . . . . . . 55 D e p t h Jumps ( A v e r a g e d T r i a l s ) . . . . . . 56 v i L I S T OF TABLES T a b l e Page 1 Means f o r H e i g h t Jumped o v e r A l l T r i a l s 27 2 Twoway A n a l y s i s o f V a r i a n c e F o r H e i g h t Jumped O v e r A l l T r i a l s . . 27 3 Summary o f Means 29 .4 Summary o f Energy. G a i n s A n a l y s i s . . . . . . . 31 5 Means o f E c c e n t r i c E n e r g y From S u b j e c t -A v e r a g e d D a t a 32 6 Twoway A n a l y s i s o f V a r i a n c e F o r E c c e n t r i c E n e r g y . 33 7 Twosample T T e s t F o r E c c e n t r i c E n e r g y D J ( " n o " mat) v s D J ( " w i t h " mat) 34 8 Twosample T T e s t F o r Drop H e i g h t D J / t , „ • v vs DJ,,, . ... „ . N 34 ( n o mat) ( w i t h mat) 9 Twosample T T e s t F o r L o w e s t D i s p l a c e m e n t D J / M „ . v vs DJ,„ ... „ _ N 34 ( n o mat) ( w i t h mat) v i i L I S T OF FIGURES F i g u r e Page 1 R e c o r d o f P u s h Down F o r c e V e r s u s Time o f a V e r t i c a l Jump 22 2 T y p i c a l F o r c e - T i m e C u r v e F o r S q u a t Jump 24 3 T y p i c a l F o r c e - T i m e C u r v e F o r Cou n t e r m o v e m e n t Jump . . . . . 25 4 T y p i c a l F o r c e - T i m e C u r v e F o r D e p t h Jump 26 ACKNOWLEDGEMENTS v i 11 T h i s i n v e s t i g a t o r w i s h e s t o t h a n k t h e members o f h i s c o m m i t t e e : D r . K. D. C o u t t s , D r . D. G. E. R o b e r t s o n and Dr. S. R. Brown. A p a r t i c u l a r t h a n k s t o D r . C o u t t s f o r h i s u n d e r s t a n d i n g and p a t i e n c e o v e r t h e p e r i o d o f work r e q u i r e d t o c o m p l e t e t h i s t h e s i s , and h i s g u i d a n c e i n h e l p i n g t h i s s t u d e n t d e v e l o p a g r e a t e r k n o w l e d g e o f t h e j u m p i n g a c t i o n by humans, a n d , as w e l l , h i s a s s i s t a n c e i n p r e p a r i n g t h e s t a t i s t i c s i n f o r m a t i o n . A s p e c i a l t h a n k s t o Dr\ R o b e r t s o n f o r h i s t h o u g h t p r o v o k i n g c r i t i c i s m s , and o u r f a r r a n g i n g d i s c u s s i o n s i n t o t h e m e c h a n i c s and p h y s i o l o g y o f j u m p i n g . A p p r e c i a t i o n i s e x p r e s s e d t o t h e f i f t e e n young women who v o l u n t e e r e d t o p a r t i c i p a t e i n t h e i n v e s t i g a t i o n as s u b j e c t s . And f i n a l l y , t h i s i n v e s t i g a t o r w i s h e s t o e x p r e s s h i s g r a t i t u d e t o h i s f a m i l y , f r i e n d s and M i s s D i a n n e Lowe f o r t h e i r s u p p o r t and e n c o u r a g e m e n t t h r o u g h o u t t h e s t u d y . CHAPTER I STATEMENT OF THE PROBLEM INTRODUCTION The v e r t i c a l jump has l i t t l e o r no h o r i z o n t a l m o t i o n . T h i s t y p e o f jump i s n o r m a l l y a c c o m p l i s h e d by b e n d i n g t h e k n e e s and l o w e r i n g o n e s e l f i n t o a s e m i - s q u a t t i n g p o s i t i o n , f r o m w h i c h one w i l l p ush down f o r c e f u l l y on t h e f l o o r , s t r a i g h t e n i n g t h e body a t t h e k n e e s and h i p s a s w e l l as a g g r e s s i v e l y s w i n g i n g t h e arms upward. T h e s e a c t i o n s a c c e l e r a t e t h e j u m p e r ' s c e n t e r o f g r a v i t y u p w a r d , i n c r e a s i n g i t s v e l o c i t y u n t i l t h e body i s f u l l y e x t e n d e d and t h e f e e t . l e a v e - t h e f l o o r . The v e l o c i t y a t t h i s p o i n t i s t h e t a k e - o f f v e l o c i t y t h a t d e t e r m i n e s how h i g h t h e c e n t e r o f g r a v i t y w i l l r i s e and how l o n g one w i l l r e m a i n i n t h e a i r ( B r a n c a z i o , 1 9 8 4 ) . When t h e m u s c l e i s s t r e t c h e d , as t h e q u a d r i c e p s a r e d u r i n g t h e s e m i - s q u a t t i n g a c t i o n i n t h e above e x a m p l e , r e f l e x c o n t r a c t i o n s r e s u l t . T h e s e a r e c a l l e d t h e m y o t a t i c and f u n c t i o n a l s t r e t c h r e f l e x . K r e i g h b a u m and B a r t h e l s ( 1 9 8 5 ) e x p l a i n how t h e s t r e t c h r e s u l t i n g f r o m a b a c k s w i n g o r s e m i - s q u a t t i n g a c t i o n i n t h e p r e p a r a t o r y phase o f a s k i l l s t o r e s e l a s t i c e n e r g y i n t h e m u s c l e . T h i s e n e r g y i s r e l e a s e d t h r o u g h a r e c o i l t y p e a c t i o n when t h e m u s c l e c o n t r a c t s d u r i n g t h e e x e c u t i o n p h a s e o f t h e s k i l l . One o f t h e m a j o r f o c u s e s t o d a y i s t o t r a i n t h e n e u r o m u s c u l a r s y s t e m t o more e f f i c i e n t l y i n t e g r a t e t h e f u n c t i o n a l s t r e t c h r e f l e x and s t o r e d e l a s t i c e n e r g y i n t o t h e s u b s e q u e n t c o n t r a c t i o n o f t h e a p p r o p r i a t e m u s c l e s . 2 P l y o m e t r i c t r a i n i n g i s t h e name e m b r a c i n g d e p t h j u m p i n g , r e b o u n d j u m p i n g , b o u n d i n g , e t c . , a l l methods used t o t r a i n t h e n e u r o m u s c u l a r s y s t e m . I n jump t r a i n i n g , p l y o m e t r i c e x e r c i s e s a r e used t o l o a d t h e w o r k i n g m u s c l e s by u s i n g t h e k i n e t i c e n e r g y o f t h e body l a n d i n g f o l l o w i n g a d r o p , p u t t i n g t h e s e l e g m u s c l e s on s t r e t c h , e l i c i t i n g an. e c c e n t r i c c o n t r a c t i o n ( s t o r i n g e l a s t i c p o t e n t i a l e n e r g y ) f o l l o w e d i m m e d i a t e l y by a c o n c e n t r i c c o n t r a c t i o n . I t i s t h e d r a m a t i c p l y o m e t r i c a c t i o n d u r i n g t r a i n i n g t h a t c a u s e s o v e r u s e i n j u r i e s t o o c c u r ( i . e . , a n t e r i o r c o m p a r t m e n t s y n d r o m e , s t r e s s e d knee l i g a m e n t s , t i b i a l s t r e s s f r a c t u r e , e t c . ) . As a r e s u l t , many c o a c h e s u t i l i z e mats o f v a r i o u s t h i c k n e s s t o h e l p e a s e t h e s t r e s s o f p l y o m e t r i c jump t r a i n i n g ( e . g . , C a n a d i a n M ens 1 N a t i o n a l V o l l e y b a l l t e a m ) . Such mats w o u l d a p p e a r t o a c t c o n t r a r y t o t h e p u r p o s e o f p l y o m e t r i c t r a i n i n g . T h a t i s , t h e d r a m a t i c p r e - s t r e c t c h i n g o f t h e w o r k i n g m u s c l e i s n o t o c c u r r i n g as t h e c o a c h e s b e l i e v e . N e v e r t h e l e s s , and d e s p i t e t h i s a p p a r e n t i n c o n s i s t e n c y , j u m p i n g i m p r o v e m e n t c o n t i n u e s t o be a c h i e v e d . T h i s i n v e s t i g a t o r b e l i e v e s t h a t p l y o m e t r i c t r a i n i n g w i t h mats i n c r e a s e s t h e s t r e s s ( o v e r l o a d ) on t h e m u s c l e more t h a n o t h e r t y p e s o f p l y o m e t r i c t r a i n i n g by s l o w i n g t h e movement a l l o w i n g t h e m u s c l e t o p e r f o r m i t s c o n t r a c t i o n w i t h g r e a t e r f o r c e b e c a u s e o f i t s i n h e r e n t a b i l i t y t o p r o d u c e l a r g e f o r c e when i t s v e l o c i t y o f c o n t r a c t i o n i s r e d u c e d ( f o r c e - v e l o c i t y r e l a t i o n s h i p ) . R e s e a r c h i s r e q u i r e d t o document e v i d e n c e o f t h e r o l e a b s o r b e n t s u r f a c e s p l a y i n d y n a m i c jump t r a i n i n g . EXPLANATION OF THE STUDY Many o f t h e p r e v i o u s jump s t u d i e s done w i t h a t h l e t e s c o n c e n t r a t e d on t h e d e v e l o p m e n t o f t h e n e u r o m u s c u l a r s y s t e m t o i m p r o v e t h e i n t e g r a t i o n o f t h e s t o r e d r e c o i l o r e l a s t i c e n e r g y w i t h t h e m u s c l e ' s c o n t r a c t i l e c omponent. The a p p a r e n t s u c c e s s o f t h e j u m p i n g p r o g r a m s o f teams who use a b s o r b e n t s u r f a c e s ( m a t s ) t o t r a i n on s u g g e s t a f a c t o r t h a t may have been o v e r l o o k e d . . T h i s i n v e s t i g a t o r s u g g e s t s t h a t some o t h e r a s p e c t o f m u s c l e p h y s i o l o g y i s b e i n g t r a i n e d o t h e r t h a n t h e u t i l i z a t i o n o f s t o r e d r e c o i l e n e r g y . To be more s p e c i f i c , t h e c o n t r a c t i l e component i s r e c e i v i n g t h e b e n e f i t s o f t h e t r a i n i n g r e g i m e n . T h i s s t u d y , t h e r e f o r e , c o n c e n t r a t e s on t h e m u s c l e c o n t r a c t i l e component and i n v e s t i g a t e s a method by w h i c h t h e c o n t r a c t i l e component may be i s o l a t e d f r o m t h e r e c o i l e f f e c t s o f s t o r e d e l a s t i c e n e r g y . T h i s t h e s i s , t h e r e f o r e , i s a b e g i n n i n g i n t h e s t u d y o f t h e e f f e c t s o f a b s o r b e n t s u r f a c e s i n jump t r a i n i n g . DELIMITATIONS 1. The s u b j e c t s o f t h i s i n v e s t i g a t i o n were f e m a l e v o l l e y b a l l p l a y e r s p a r t i c i p a t i n g on u n i v e r s i t y , c o l l e g e a n d / o r t h e B r i t i s h C o l u m b i a P r o v i n c i a l J u v e n i l e Team. LIMITATIONS 1, The t i m e i n t h e a i r was u s e d t o c a l c u l a t e t h e h e i g h t o f r i s e o f e a c h s u b j e c t ' s c e n t e r o f g r a v i t y . 2. A 0.64 x 0.44 x 0.20 m pad c o m p r i s i n g sponge m a t e r i a l s was u s e d t o s i m u l a t e a 0.20 m t h i c k g y m n a s t i c mat. DEFINITION OF TERMS 1. C o n c e n t r i c C o n t r a c t i o n . When a m u s c l e c o n t r a c t s w h i l e s h o r t e n i n g . An e x a m p l e i s when t h e knee e x t e n s o r s ( q u a d r i c e p s m u s c l e s ) s h o r t e n and t h e k n e e s s t r a i g h t e n , r a i s i n g t h e body, as i n j u m p i n g . 2. C o n c e n t r i c P h a s e . T h a t p a r t o f t h e j u m p i n g movement when f o r c e i s b e i n g a p p l i e d t o t h e j u m p i n g s u r f a c e and upward movement i s b e i n g r e a l i z e d by t h e b o d y ' s c e n t e r o f g r a v i t y . C h a r a c t e r i z e d by a c o n c e n t r i c c o n t r a c t i o n o f some o f t h e j u m p i n g m u s c l e s . 3. C o n t r a c t i l e Component. The component o f m u s c l e t h a t c r e a t e s f o r c e by t h e c a t a b o l i s m o f ATP and CP. 4. Counte r m o v e m e n t P h a s e . I n v e r t i c a l j u m p i n g , i t i s t h e b e n d i n g a t t h e k n e e s u n d e r t h e p u l l o f g r a v i t y , w h i c h a jumper a l l o w s , t o l o w e r i n t o a s e m i - s q u a t p o s i t i o n i n p r e p a r a t i o n t o p e r f o r m i n g a jump. An e c c e n t r i c c o n t r a c t i o n i s r e q u i r e d t o d e c e l e r a t e t h e b o d y ' s downward m o t i o n t o z e r o w h i c h p r e c e d e s t h e c o n c e n t r i c c o n t r a c t i o n . 5. Countermovement Jump. A v e r t i c a l jump begun f r o m a s t a n d i n g p o s i t i o n w h i c h i s p r e c e d e d by a c o u n t e r m o v e m e n t . 6. D e p t h Jump. A p l y o m e t r i c e x e r c i s e where an a t h l e t e d r o p s f r o m a h e i g h t and i m m e d i a t e l y upon l a n d i n g moves t h e body d i r e c t l y upward as r a p i d l y as p o s s i b l e . The e s s e n c e o f t h e movement i s t h a t i t be a " t o u c h and go". T h a t i s , do i t q u i c k l y ( C h u , 1 9 8 3 ) . 7. Drop Jump. Same as D e p t h Jump. 5 8. E c c e n t r i c C o n t r a c t i o n . O c c u r s when a m u s c l e l e n g t h e n s d u r i n g t h e d e v e l o p m e n t o f a c t i v e t e n s i o n . 9. E l a s t i c E n e r g y . The e n e r g y t o do work f o l l o w i n g a m u s c l e s t r e t c h due t o t h e e l a s t i c p r o p e r t i e s o f t h e m u s c l e and a s s o c i a t e d c o n n e c t i v e t i s s u e . 10. E c c e n t r i c E n e r g y . I n t h i s t h e s i s , i t i s u s e d t o i d e n t i f y t h e l o s s o f p o t e n t i a l e n e r g y ( n e g a t i v e w o rk) w h i c h o c c u r s d u r i n g t h e c o u n t e r m o v e m e n t phase i n v e r t i c a l j u m p i n g . See C o u n t e r m o v e m e n t P h a s e , a n d / o r M e c h a n i c a l Work. 11. I s o m e t r i c C o n t r a c t i o n . A m u s c l e c o n t r a c t i o n i n w h i c h t e n s i o n i s d e v e l o p e d b u t t h e r e i s no ch a n g e i n e x t e r n a l l e n g t h o f t h e m u s c l e ; t h e r e i s no movement. O c c u r s when t h e m u s c u l a r f o r c e i s u n a b l e t o overcome an e x t e r n a l r e s i s t a n c e . 12. K i n e t i c E n e r g y . The e n e r g y t h a t a body p o s s e s s e s b e c a u s e i t i s i n m o t i o n . 13. M e c h a n i c a l Work. The p r o d u c t o f t h e f o r c e a p p l i e d t o a body and t h e d i s t a n c e t h r o u g h w h i c h t h e body moves i n t h e d i r e c t i o n i n w h i c h t h e f o r c e a c t s . I n g i v e n s i t u a t i o n s i t c a n be p o s i t i v e , z e r o , o r n e g a t i v e . I n j u m p i n g , t h e upward movement o f t h e body i s s a i d t o be c a u s e d by p o s i t i v e work b e c a u s e t h e movement i s i n t h e same d i r e c t i o n i n w h i c h t h e f o r c e a c t s . On t h e o t h e r h a n d , when t h e body i s l o w e r e d u n d e r t h e i n f l u e n c e o f g r a v i t y , work i s . s a i d t o be n e g a t i v e . From a m u s c u l a r s t a n d p o i n t , p o s i t i v e and n e g a t i v e work c a n be e q u a t e d w i t h c o n c e n t r i c and e c c e n t r i c c o n t r a c t i o n s , r e s p e c t i v e l y . 6 14. P l y o m e t r i c s . E x e r c i s e s c h a r a c t e r i z e d by p o w e r f u l m u s c u l a r c o n t r a c t i o n i n r e s p o n s e t o t h e r a p i d , dynamic l o a d i n g ( s t r e t c h i n g ) o f t h e i n v o l v e d m u s c l e s ( R a d c l i f f e and F a r e n t i n o s , 1 9 8 4 ) . T y p i c a l p l y o m e t r i c e x e r c i s e s f o r j u m p i n g a r e b o u n d i n g and d e p t h j u m p i n g . 15. P o s t - s t r e t c h Work. The e n h a n c e d a b i l i t y o f m u s c l e s t o do work d u r i n g a c o n c e n t r i c c o n t r a c t i o n f o l l o w i n g a p r e - s t r e t c h movement. See E l a s t i c E n e r g y . 16. P o t e n t i a l E n e r g y . The e n e r g y t h a t a body p o s s e s s e s b e c a u s e o f i t s p o s i t i o n e i t h e r above t h e l e v e l o f t h e e a r t h ' s s u r f a c e o r due t o i t s e l a s t i c p r o p e r t i e s . 17. P r e p a r a t o r y P h a s e . See C ountermovement P h a s e , a n d / o r M e c h a n i c a l Work. 18. S q u a t Jump. A v e r t i c a l jump begun f r o m a c r o u c h e d p o s i t i o n w i t h t h e k n e e s b e n t a t 90°. A v e r t i c a l jump where an i s o m e t r i c c o n t r a c t i o n p r e c e d e s t h e c o n c e n t r i c c o n t r a c t i o n . HYPOTHESIS 1. The use o f a foam mat t o a b s o r b e n e r g y d u r i n g t h e c o u n t e r m o v e m e n t phase o f a m u s c u l a r e f f o r t w i l l r e d u c e t h e m u s c l e s a b i l i t y t o p e r f o r m p o s t - s t r e t c h work. H o : V'no" mat) = X ( " w i t h " mat) A l t . : Y ( " n o " m a t ) * X ( " w i t h " mat) o r TT 2 2 o s ("no" mat) " s ( " w i t h " mat) 2 2 A l t ' : s ("no" mat) ^ S ( " w i t h " mat) 7 CHAPTER I I REVIEW OF LITERATURE RECOIL ENERGY • . ' A m u s c l e c a n be p e r c e i v e d as a s t r u c t u r e o f c o n t r a c t i l e and e l a s t i c c o m p o n e n t s , w i t h b o t h c o n t r i b u t i n g t o t h e d e v e l o p m e n t o f m u s c u l a r f o r c e . N o r m a l l y , human m o t i o n i s i n i t i a t e d by an e c c e n t r i c ( l e n g t h e n i n g ) c o n t r a c t i o n o f t h e a p p r o p r i a t e s k e l e t a l m u s c l e s f o l l o w e d i m m e d i a t e l y by a c o n c e n t r i c ( s h o r t e n i n g ) c o n t r a c t i o n . T h i s s u g g e s t s t h a t d u r i n g t h e e c c e n t r i c s t a g e t h e m u s c l e p e r f o r m s s i m i l a r l y t o a s t r e t c h e d e l a s t i c , s t o r i n g p o t e n t i a l e n e r g y . The s t o r e d ( p o t e n t i a l ) e n e r g y , t h e r e f o r e , i s an a d d i t i v e f o r c e - c o m b i n i n g w i t h t h e 0 c o n t r a c t i l e component d u r i n g t h e c o n c e n t r i c phase p r o d u c i n g e n h a n c e d m e c h a n i c a l work. F u r t h e r m o r e , t h e m u s c l e ' s a b i l i t y t o c r e a t e f o r c e i s en h a n c e d by some n e u r o m u s c u l a r mechanisms as y e t n o t f u l l y i d e n t i f i e d . I n a t h l e t i c s t h i s e n h a n c e d m e c h a n i c a l work i s d e m o n s t r a t e d by j u m p i n g h i g h e r , r u n n i n g f a s t e r , t h r o w i n g o b j e c t s f u r t h e r , e t c . C a v a g n a , e t a l . ( 1 9 6 8 ) e x p e r i m e n t i n g on i s o l a t e d t o a d s a r t o r i u s and f r o g g a s t r o c n e m i u s , and human f o r e a r m f l e x o r s , f o u n d t h a t t h e f o r c e d e v e l o p e d by t h e c o n t r a c t i l e component, when t h e m u s c l e s h o r t e n e d a f t e r b e i n g s t r e t c h e d , i s g r e a t e r t h a n t h a t d e v e l o p e d when i t s h o r t e n s f r o m a s t a t e o f i s o m e t r i c c o n t r a c t i o n . Asmussen and B o n d e - P e t e r s e n ( 1 9 7 4 ) used t h r e e t y p e s o f m a x i m a l v e r t i c a l jumps t o s t u d y t h e f o r c e e enhancement a f t e r p r e - s t r e t c h i n g i n human s k e l e t a l m u s c l e . The t h r e e t y p e s o f jumps we r e : ( 1 ) begun f r o m a s e m i - s q u a t t i n g p o s i t i o n ; ( 2 ) p e r f o r m e d f o l l o w i n g a n a t u r a l c o u n t e r m o v e m e n t f r o m a s t a n d i n g p o s i t i o n ; and ( 3 ) a f t e r d r o p ( d e p t h ) jumps f r o m h e i g h t s o f 0.23, 0.404 and 0.69 m. They f o u n d t h e h e i g h t o f jump i n c r e a s e d w i t h i n c r e a s i n g amounts o f e c c e n t r i c e n e r g y up t o a c e r t a i n l e v e l . The m a x i m a l l e v e l d e m o n s t r a t e d was t h e e c c e n t r i c l a n d i n g f o r c e g e n e r a t e d f r o m a 0.404 m d e p t h jump. I n c r e a s e s i n a v e r a g e c o n c e n t r i c e n e r g y ( u s i n g t h e s e m i - s q u a t d a t a as t h e b a s e l i n e m e a s u r e ) were a c h i e v e d by t h e c o u n t e r m o v e m e n t jump ( 2 2 . 9 % ) and t h e t h r e e l e v e l s o f d e p t h jumps ( 1 3 . 2 % , 10.5% and 3.3% r e s p e c t i v e l y ) . Asmussen and B o n d e - P e t e r s e n c o n c l u d e d t h a t t h e e c c e n t r i c ( o r n e g a t i v e w o r k ) phase s t o r e d e l a s t i c e n e r g y i n t h e w o r k i n g m u s c l e s r e s u l t i n g i n i n c r e a s e s i n j u m p i n g h e i g h t . O t h e r r e s e a r c h e r s (Komi and B o s c o , 1978; B o s c o , e t a l . 1982) have c o n f i r m e d t h e phenomenon o f s t o r a g e o f e l a s t i c p o t e n t i a l e n e r g y i n m u s c l e t h r o u g h t h e e c c e n t r i c s t r e t c h i n g o f m u s c l e s i m m e d i a t e l y p r i o r t o t h e work p r o d u c i n g c o n c e n t r i c c o n t r a c t i o n . The r e s e a r c h i d e n t i f i e s two c r i t i c a l f a c t o r s w h i c h a f f e c t t h e e f f i c i e n c y o f t h e u t i l i z a t i o n o f t h e r e c o i l component i n d y n a m i c m u s c u l a r c o n t r a c t i o n s . F i r s t , m u s c u l a r f o r c e i s i n c r e a s e d w i t h t h e g r e a t e r l e n g t h t h e m u s c l e i s s t r e t c h e d ( C a v a g n a , e t a l . 1 9 6 8 ) ; and s e c o n d , t h e spe e d o f 9 p r e s t r e t c h i n g e n h a n c e s t h e m u s c l e ' s e l a s t i c component (Komi and B o s c o , 19.78; H a k k i n e n and K o m i , 1 9 8 3 ) . However, t h e r e s e a r c h i n d i c a t e s t h a t t h e r e a r e m a x i m a l v a l u e s o f r a t e o f s t r e t c h i n g and l e n g t h o f s t r e t c h . T h a t i s , u t i l i z a t i o n o f e l a s t i c e n e r g y d e c r e a s e s w i t h v e r y h i g h s t r e t c h l o a d s , w i t h v e l o c i t y o f s t r e t c h b e i n g t h e d o m i n a n t f a c t o r (Komi and B o s c o , 1 9 7 8 ) . No r e s e a r c h was f o u n d on t h e d y n a m i c i n t e r a c t i o n b etween a m u s c l e ' s c o n t r a c t i l e and r e c o i l c o m p o n e n t s . C a v a g n a , e t a l . ( 1 9 6 8 ) b r i e f l y e x p l o r e d t h e r o l e o f t h e c o n t r a c t i l e component i n t h e s t r e t c h / s h o r t e n i n g d y n a m i c s of m u s c l e s . They t e n t a t i v e l y c o n c l u d e d t h a t t h e c o n t r a c t i l e component d u r i n g j u m p i n g does d i s p l a y a g r e a t e r f o r c e d u r i n g t h e s t r e t c h / s h o r t e n i n g c o n t r a c t i o n s e q u e n c e o f a n o r m a l jump v e r s u s s t a r t i n g f r o m a s t a t i c i s o m e t r i c c o n t r a c t i o n . L a t e r , C a v a g n a , e t a l . ( 1 9 7 1 ) s u g g e s t t h a t t h e s p e e d o f s h o r t e n i n g by t h e c o n t r a c t i l e component i s a l i m i t i n g f a c t o r o f t h e m a x i m a l upward v e r t i c a l s p e e d of a j u m p e r ' s c e n t e r o f g r a v i t y (C o f G ) . T h e r e i s a s u g g e s t i o n , t h e r e f o r e , t h a t a h i g h e r . s h o r t e n i n g r a t e by a m u s c l e ' s c o n t r a c t i l e component w i l l i m p r o v e t h e e f f i c i e n c y o f i n t e g r a t i n g t h e m u s c l e ' s s t o r e d r e c o i l component w i t h t h e c o n c e n t r i c c o n t r a c t i o n . I t i s t h i s p o i n t w h i c h i s t h e u n d e r l y i n g a s s u m p t i o n f o r t h i s t h e s i s . T h i s r e s e a r c h e r e n d e a v o r s w i t h t h i s s t u d y t o d e m o n s t r a t e a method i n w h i c h r e c o i l e n e r g y c a n be d i s s i p a t e d , i s o l a t i n g t h e m u s c l e c o n t r a c t i l e component as t h e f o r c e g e n e r a t o r f o r v e r t i c a l jump t r a i n i n g . 10 S P E C I F I C I T Y OF TRAINING H a k k i n e n and Komi ( 1 9 8 3 ) have shown t h a t s t r e n g t h t r a i n i n g p r o d u c e s i n c r e a s e d m a x i m a l i s o m e t r i c f o r c e . T h i s i m p r o v e m e n t i s m a n i f e s t e d by t h e c o n t r a c t i l e component of m u s c l e s . P r e v i o u s l y , h o w e v e r , P e t e r s e n e t a l . ( 1 9 6 1 ) i n d i c a t e d t h a t i n c r e a s e s i n i s o m e t r i c f o r c e do n o t n e c e s s a r i l y m a n i f e s t s i m i l a r i m p r o v e m e n t s i n d y n a m i c f o r c e ( o r m e c h a n i c a l w o r k ) . A s t r a n d and R o d a h l ( 1 9 7 7 ) c l a i m t h a t s t r e n g t h i n c r e a s e s i n one a c t i v i t y may n o t i m p r o v e s t r e n g t h i n o t h e r t y p e s o f a c t i v i t i e s - i . e . , l i f t i n g w e i g h t s f r o m a h a l f - s q u a t v e r s u s j u m p i n g . T h i s i s known as the. " p r i n c i p l e o f s p e c i f i c i t y " and i s a w e l l known c o n c e p t where t h e e f f e c t s o f a d a p t a t i o n t o t r a i n i n g a r e t h e sum o f t h e m o d i f i c a t i o n s b r o u g h t a b o u t by t h e r e p e t i t i o n o f d a i l y e x e r c i s e s t h a t a r e s p e c i f i c f o r t h e t y p e o f t r a i n i n g b e i n g c a r r i e d o u t ( B o s c o , e t a l . 1 9 8 2 ) . I n j u m p i n g , one way. t o a p p l y t h i s " p r i n c i p l e " w i t h r e g a r d t o i m p r o v i n g t h e r a t e o f s h o r t e n i n g by a m u s c l e ' s c o n t r a c t i l e component w o u l d be t o do j u m p i n g e x e r c i s e where r e c o i l e n e r g y i s e l i m i n a t e d ( i . e , d e p t h j u m p s , b o u n d i n g , e t c . ) . SUMMARY I n summary, m u s c l e s have two c o m p o n e n t s w h i c h c o n t r i b u t e t o d y n a m i c c o n t r a c t i o n s : c o n t r a c t i l e and r e c o i l . The r e c o i l c o m ponent, t h e s t o r i n g o f r e c o i l p o t e n t i a l e n e r g y i n a m u s c l e by s t r e t c h i n g i t i m m e d i a t e l y p r i o r t o p e r f o r m i n g a c o n c e n t r i c c o n t r a c t i o n , h a s been w e l l e s t a b l i s h e d . D u r i n g t h e c o n c e n t r i c c o n t r a c t i o n a. summation o c c u r s between t h e s t o r e d r e c o i l e n e r g y and t h e m u s c l e ' s c o n t r a c t i l e component, i m p r o v i n g t h e f i n a l o u t p u t o f m e c h a n i c a l work. The g r e a t e r t h e speed, o f s t r e t c h i n g and t h e g r e a t e r t h e l e n g t h t h e m u s c l e i s s t r e t c h e d t h e g r e a t e r t h e amount o f r e c o i l e n e r g y . I n a d d i t i o n , C a v agna e t a l . ( 1 9 7 1 ) i n d i c a t e d t h a t t h e r a t e o f s h o r t e n i n g by t h e c o n t r a c t i l e component i s t h e l i m i t i n g f a c t o r i n e f f i c i e n t l y i n t e g r a t i n g r e c o i l e n e r g y i n t o t h e c o n t r a c t i o n . One way, t h e r e f o r e , t o i m p r o v e a m u s c l e ' s a b i l i t y t o c o n t r a c t w i t h g r e a t e r power ( i . e . , w h i l e j u m p i n g ) w o u l d be t o t r a i n t h e c o n t r a c t i l e c o m p o n e n t ' s a b i l i t y t o s h o r t e n a t a more r a p i d r a t e . F i n a l l y , an i m p o r t a n t c o n s i d e r a t i o n i n d e v e l o p i n g t h i s c a p a b i l i t y i s t o a p p l y t h e " p r i n c i p l e o f s p e c i f i c i t y " i n t h e d e s i g n o f t r a i n i n g e x e r c i s e s . A c c o r d i n g l y , a way t o make g a i n s i n i m p r o v i n g t h e r a t e o f s h o r t e n i n g by a m u s c l e ' s c o n t r a c t i l e component w o u l d be t o use e x e r c i s e s w h i c h e l i m i n a t e t h e r e c o i l component and a t t h e same t i m e a r e s p e c i f i c t o t h e j u m p i n g s k i l l . AIM C o n s i d e r i n g t h a t t h e r a t e o f s t r e t c h i n g a m u s c l e u n d e r g o e s i s a m a j o r f a c t o r i n t h e p r o d u c t i o n o f r e c o i l e n e r g y , one way t o m i n i m i z e or e l i m i n a t e t h i s e n e r g y w o u l d be t o r e d u c e t h e r a t e o f t h e e c c e n t r i c c o n t r a c t i o n . The s q u a t - j u m p i s a method w h i c h i s o l a t e s t h e c o n t r a c t i l e component i n j u m p i n g . However, i t l a c k s s p e c i f i c i t y and i s . . . 12 t i m e c o n s u m i n g . T h i s r e s e a r c h e r r e j e c t s t h e s q u a t - j u m p ; i t i s an i n e f f i c i e n t t r a i n i n g e x e r c i s e . P l y o m e t r i c t y p e e x e r c i s e s a r e common and s u c c e s s f u l t r a i n i n g e x e r c i s e s w h i c h have a h i g h " s p e c i f i c i t y " c omponent. T h e r e f o r e , p l y o m e t r i c j u m p i n g e x e r c i s e s meet t h i s r e q u i r e m e n t . U s i n g a h i g h l y a b s o r b e n t l a n d i n g / j u m p i n g s u r f a c e c o u l d p r o d u c e t h i s r e d u c t i o n i n t h e r a t e o f t h e e c c e n t r i c c o n t r a c t i o n . A g y m n a s t i c l a n d i n g mat ( a p p r o x i m a t e l y 0.20 m t h i c k ) i s p e r c e i v e d as a h i g h l y a b s o r b e n t s u r f a c e and w o u l d f i t t h i s m o d e l . T h i s s t u d y , t h e r e f o r e , has t h e g o a l t o d e t e r m i n e w h e t h e r a h i g h l y a b s o r b e n t l a n d i n g / j u m p i n g s u r f a c e w i l l m i n i m i z e ( o r e l i m i n a t e ) t h e s t o r a g e o f r e c o i l e n e r g y i n human m u s c l e w h i l e p e r f o r m i n g v e r t i c a l j u m p s . 13 CHAPTER I I I METHODS AND PROCEDURES INTRODUCTION Asmussen and B o n d e - P e t e r s e n ( 1 9 7 4 ) d i d an e x p e r i m e n t where t h r e e t y p e s o f v e r t i c a l jumps were u s e d i n s t u d y i n g t h e q u e s t i o n , "Can m u s c l e s a b s o r b and t e m p o r a r i l y s t o r e m e c h a n i c a l e n e r g y i n t h e f o r m o f e l a s t i c e n e r g y f o r l a t e r r e - u s e ? " . The t h r e e t y p e s o f jumps we r e : ( 1 ) s q u a t jump, ( 2 ) c o u n t e r m o v e m e n t jump, and ( 3 ) d r o p jump p e r f o r m e d f r o m t h r e e d i f f e r e n t h e i g h t s . Komi and B o s c o ( 1 9 7 8 ) used t h e Asmussen and B o n d e - P e t e r s e n model t o e x a m i n e t h e e f f e c t s o f d i f f e r e n t s t r e t c h l o a d s on a c t i v a t e d l e g e x t e n s o r m u s c l e s . T h i s s t u d y a l s o used t h i s model t o compare t h e t h r e e t y p e s of j u m p s , e a c h p e r f o r m e d o f f two d i f f e r e n t j u m p i n g / l a n d i n g s u r f a c e s , one b e i n g a " n o r m a l " s u r f a c e , t h e o t h e r b e i n g a 0.20 m t h i c k foam " a b s o r b e n t " j u m p i n g / l a n d i n g mat. SUBJECTS The t e s t i n g f o r t h i s s t u d y was c o m p l e t e d o v e r a f i v e day. p e r i o d i n J u l y 1984 where f i f t e e n (N = 15) f e m a l e h i g h s c h o o l , c o l l e g e and u n i v e r s i t y v o l l e y b a l l p l a y e r s aged 18 t o 24 y e a r s (X = 18.75 y r s . ) were t h e s u b j e c t s . E a c h s u b j e c t p e r f o r m e d 18 v e r t i c a l jumps: n i n e ( 9 ) o f f a f o r c e p l a t e and n i n e ( 9 ) o f f a 0.20 m t h i c k a b s o r b e n t mat on t o p t h e f o r c e p l a t e . E a c h s e r i e s o f n i n e jumps c o m p r i s e d t h r e e ( 3 ) s q u a t jump t r i a l s , t h r e e ( 3 ) c o u n t e r m o v e m e n t jump t r i a l s and t h r e e ( 3 ) d r o p jump t r i a l s f r o m a h e i g h t o f 0.40 m. The d r o p jump i s commonly known as a d e p t h jump i n N o r t h A m e r i c a and w i l l be t h e t e r m u s e d i n t h i s s t u d y . The s q u a t jump was p e r f o r m e d f r o m a s t a t i c a l l y h e l d s e m i - s q u a t p o s i t i o n ( k n e e s f l e x e d a p p r o x i m a t e l y 90°) where no p r e p a r a t o r y c o u n t e r m o v e m e n t was a l l o w e d . E a c h c o u n t e r m o v e m e n t jump commenced f r o m an e r e c t s t a n d i n g p o s i t i o n w i t h a n o r m a l p r e p a r a t o r y c o u n t e r m o v e m e n t b e i n g p e r f o r m e d i m m e d i a t e l y p r i o r t o e x e c u t i n g t h e jump. F o r t h e d e p t h jump, e a c h s u b j e c t s t o o d e r e c t on a box 0.40 m h i g h , s t e p p e d o f f t h e box, d r o p p i n g d i r e c t l y o n t o t h e a s s i g n e d l a n d i n g / j u m p i n g s u r f a c e and i m m e d i a t e l y p e r f o r m i n g a v e r t i c a l jump. A l l jumps were p e r f o r m e d w i t h e a c h s u b j e c t k e e p i n g h e r hands on t h e h i p s t o e n s u r e d o m i n a n c e o f t h e l e g e x t e n s o r m u s c l e s . The s u b j e c t s were i n s t r u c t e d t o make e a c h jump a m a x i m a l e f f o r t and t o jump o f f b o t h f e e t s i m u l t a n e o u s l y . Each . s u b j e c t ' s s e q u e n c e o f jumps was r a n d o m l y c h o s e n f r o m a random numbers t a b l e . T h a t i s , no two s u b j e c t s c o m p l e t e d t h e s e r i e s o f s i x s e t s o f jumps (3 t y p e s o f jumps x 2 j u m p i n g / l a n d i n g s u r f a c e s ) i n t h e same o r d e r . T h i s was done t o e n s u r e t h a t no l e a r n i n g f a c t o r i n f l u e n c e d t h e d a t a . However, e a c h s u b j e c t c o m p l e t e d h e r t h r e e t r i a l s on e a c h t y p e o f jump b e f o r e g i v i n g way t o a n o t h e r s u b j e c t o r p r o g r e s s i n g t o h e r n e x t a s s i g n e d jump. A l l t h e s u b j e c t s c o m p l e t e d a " C o n s e n t t o a B i o m e c h a n i c a l E v a l u a t i o n Form" b e f o r e p a r t i c i p a t i n g i n t h i s s t u d y ( A p p e n d i x A ) . E a c h s u b j e c t ' s a g e , h e i g h t and w e i g h t i s . l i s t e d i n A p p e n d i x C, t i t l e d I n d i v i d u a l D a t a . 15 TESTING APPARATUS A l l jump t r i a l s were p e r f o r m e d o f f a K i s t l e r F o r c e P l a t e l o c a t e d a t t h e U n i v e r s i t y o f B r i t i s h C o l u m b i a . From t h i s a l i s t i n g o f t h e v e r t i c a l g r o u n d r e a c t i o n f o r c e s v e r s u s t i m e were c o l l e c t e d u s i n g a D a t a G e n e r a l M i c r o N o v a MP/200 c o m p u t e r . A foam pad ( 0 . 6 4 x 0.44 x 0.20 m) was l a i d on t o p o f t h e f o r c e p l a t e d u r i n g t h e t h r e e t y p e s o f v e r t i c a l jumps r e q u i r i n g t h e a b s o r b e n t l a n d i n g / j u m p i n g s u r f a c e . The t o p s u r f a c e o f t h e foam mat was c o v e r e d w i t h a p r o t e c t i v e p l a s t i c c o v e r . S p e c i f i c a t i o n s f o r t h e foam mat a r e l i s t e d i n A p p e n d i x B . DATA COLLECTION The v e r t i c a l f o r c e component was s e n s e d by t h e K i s t l e r F o r c e P l a t e , t r a n s m i t t e d t o t h e D a t a G e n e r a l M i c r o N o v a MP/200 c o m p u t e r , where t h e c o m p u t e r t i m e d and r e c o r d e d i t a t p e r i o d s o f 0.01 s e c o n d , and h a r d c o p y o f t h i s v e r t i c a l f o r c e v e r s u s t i m e r e c o r d was p r i n t e d on a p e r i p h e r a l p r i n t e r . T h e s e d a t a were u s e d t o d e r i v e : ( 1 ) t h e r i s e o f t h e c e n t e r o f g r a v i t y (C o f G ) , and ( 2 ) t h e g e n e r a t e d k i n e t i c e n e r g y . An i m p u l s e a n a l y s i s was done by d o i n g an i n t e g r a t i o n on t h e above v e r t i c a l f o r c e v e r s u s t i m e r e c o r d f o r t h e c o u n t e r m o v e m e n t and d e p t h jump t r i a l s t o o b t a i n ( 3 ) , e c c e n t r i c e n e r g y / n e g a t i v e work ( r e d u c e d p o t e n t i a l e n e r g y ) g e n e r a t e d d u r i n g t h e p r e p a r a t o r y p h a s e by c o m p u t i n g t h e l o w e s t d i s p l a c e m e n t o f t h e C o f G. A d d i t i o n a l d a t a r e c o r d e d f o r t h e c o u n t e r m o v e m e n t jump and d e p t h jump i s ( 4 ) , t h e c hange i n k i n e t i c e n e r g y a c h i e v e d w i t h r e s p e c t t o t h e a s s i g n e d s q u a t jump ( c o m p a r i s o n o f d a t a i t e m 2's s q u a t jump w i t h t h e a p p l i c a b l e c o u n t e r m o v e m e n t / d e p t h j u m p ' s ) . L a s t l y , d a t a i t e m ( 5 ) , a p r e d i c t i o n o f t h e a c t u a l h e i g h t e a c h s u b j e c t d r o p p e d a f t e r s t e p p i n g o f f t h e 0.40 m h i g h box was r e c o r d e d f o r e a c h d e p t h jump. T h i s was a c r i t i c a l m e a s u r e , n e c e s s a r y t o q u a n t i f y t h e e c c e n t r i c e n e r g y a c c u m u l a t e d d u r i n g t h e c o u n t e r m o v e m e n t p h a s e o f t h e d e p t h jump. E v e r y s u b j e c t began e a c h d e p t h jump t r i a l by s t e p p i n g downward t o t h e l a n d i n g / j u m p i n g s u r f a c e . T h i s c o n t r o l l e d t h e h e i g h t o f d r o p f r o m w h i c h t h e f o r c e o f g r a v i t y a f f e c t e d e a c h j u m p e r , w h i c h i n t u r n , a f f e c t e d t h e k i n e t i c e n e r g y on l a n d i n g . As a c o n s e q u e n c e , none o f t h e s u b j e c t s ' d e p t h jumps was f r o m t h e same h e i g h t as any o f t h e o t h e r s u b j e c t s . The method o f p r e d i c t i o n i s d e t a i l e d on p a g es 19 and 20. The h e i g h t o f r i s e o f C o f G, ( d a t a i t e m ( 1 ) ) was d e t e r m i n e d by m e a s u r i n g t h e t i m e ( t o t h e n e a r e s t 0.01 s e c ) e a c h s u b j e c t was i n t h e a i r f o r e a c h jump. T h i s was o b t a i n e d f r o m t h e c o m p u t e r ' s f i l e s o f v e r t i c a l f o r c e v e r s u s t i m e r e c o r d where t h e v e r t i c a l f o r c e and t i m e a t t a k e - o f f and l a n d i n g were r e c o r d e d . Time was u s e d t o c a l c u l a t e t h e h e i g h t o f r i s e o f C o f G d e t e r m i n e d f r o m B r a n c a z i o ( 1 9 8 4 ) as f o l l o w s : v ( t o ) 1 / 2 ^ ( a i r ) H - v 2 ( t o ) / 2 g ( 2 ) Where v ( t o ) = t a k e - o f f v e l o c i t y , g = f o r c e o f g r a v i t y , t, . N = t i m e i n t h e a i r , and H = h e i g h t o f r i s e C o f G. ( a i r ) » . © D a t a i t e m ( 2 ) , k i n e t i c e n e r g y , was d e t e r m i n e d by a p p l y i n g t h e j u m p e r ' s v e r t i c a l v e l o c i t y a t t a k e - o f f and h e r mass t o t h e k i n e t i c e n e r g y f o r m u l a : KE = l / 2 m v 2 ( t o ) ( 3 ) where KE = k i n e t i c e n e r g y , m = s u b j e c t ' s mass and v, \ = t a k e - o f f v e l o c i t y , ( t o ) 3 D a t a i t e m ( 3 ) , e c c e n t r i c e n e r g y , was d e r i v e d by r u n n i n g an i m p u l s e a n a l y s i s p r o g r a m on t h e v e r t i c a l f o r c e v e r s u s t i m e r e c o r d . T h i s p r o g r a m d i d an i n t e g r a t i o n on t h e f o r c e / t i m e r e c o r d p r o d u c i n g " l o w e s t d i s p l a c e m e n t " o f t h e C o f G d u r i n g t h e p r e p a r a t o r y p h a s e o f e a c h jump. The d i f f e r e n c e b e t ween t h e h e i g h t o f C o f G when i n t h e e r e c t s t a n d i n g p o s i t i o n and i t s l o w e s t d i s p l a c e m e n t i s a measure o f n e g a t i v e work. T h i s l o w e r i n g o f e a c h s u b j e c t ' s C o f G was c o n v e r t e d t o a l o s s o f p o t e n t i a l e n e r g y as f o l l o w s : PE = wh ( 4 ) where PE = p o t e n t i a l e n e r g y , w = w e i g h t o f t h e s u b j e c t , and h = d i s t a n c e C o f G i s b e l o w i t s e r e c t s t a n d i n g h e i g h t . T h i s v a l u e o f p o t e n t i a l e n e r g y i s c a l l e d e c c e n t r i c e n e r g y . F o r t h e d e p t h jump t r i a l s , t h e e c c e n t r i c e n e r g y was a s u m m ation o f t h e downward k i n e t i c e n e r g y a c c u m u l a t e d d u r i n g t h e d r o p f r o m t h e 0.40 m box and t h e c hange i n p o t e n t i a l e n e r g y f r o m t h e t o u c h down t o t h e " l o w e s t d i s p l a c e m e n t " o f t h e C o f G. However, e a c h s u b j e c t s t e p p e d downward o f f t h e box. S i n c e t h e r e was no r e l i a b l e way t o c o n t r o l t h e amount o f s t e p - d o w n , t h e i m p u l s e a n a l y s i s p r o g r a m was used t o p r e d i c t t h e h e i g h t o f d r o p t o t h e f o r c e p l a t e . When r u n n i n g t h e i m p u l s e a n a l y s i s on t h e f o r c e / t i m e r e c o r d , d i f f e r e n t d r o p h e i g h t s t o t h e n e a r e s t 0.001 m were f e d t o t h e c o m p u t e r u n t i l t h e o u t p u t o f t a k e - o f f v e l o c i t y c l o s e l y a p p r o x i m a t e d t h e v a l u e u s e d t o c a l c u l a t e h e i g h t o f jump ( d a t a i t e m ( 1 ) ) . From t h i s r e v i s e d d r o p h e i g h t downward d i r e c t e d k i n e t i c e n e r g y was d e t e r m i n e d : M l a n d ) . - 2 § h <5> KE - l / 2 m v 2 ( l a n d ) ( 6 ) where v ( i a n c j ) = v e l o c i t y a t l a n d i n g f r o m d r o p jump, h = d r o p h e i g h t , g = f o r c e o f g r a v i t y , m = s u b j e c t ' s mass . and KE = k i n e t i c e n e r g y . The i m p u l s e a n a l y s i s p r o g r a m , as i n t h e c o u n t e r m o v e m e n t e v e n t s , gave an o u t p u t o f l o w e s t d i s p l a c e m e n t f o r C o f G ( t h e d i s t a n c e b e t w e e n h e i g h t o f C o f G a t t o u c h down t o i t s h e i g h t when downward m o t i o n e q u a l l e d z e r o ) . The l o s s i n p o t e n t i a l e n e r g y was d e r i v e d f r o m t h i s l o w e s t d i s p l a c e m e n t o f C o f G v a l u e u s i n g e q u a t i o n ( 4 ) . F i n a l l y , t h e l o s s i n p o t e n t i a l e n e r g y was summed w i t h t h e downward d i r e c t e d k i n e t i c e n e r g y and c a l l e d e c c e n t r i c e n e r g y . Change i n k i n e t i c e n e r g y , d a t a i t e m ( 4 ) , was c a l c u l a t e d f i r s t , by a v e r a g i n g e a c h s u b j e c t ' s t h r e e t r i a l s f o r k i n e t i c e n e r g y ( d a t a i t e m ( 2 ) ) f o r e a c h t y p e o f jump, and s e c o n d , by s u b t r a c t i n g e a c h s u b j e c t ' s a v e r a g e d s q u a t jump v a l u e f r o m t h e a p p l i c a b l e c o u n t e r m o v e m e n t and d e p t h jump a v e r a g e o f k i n e t i c e n e r g y . T h i s d a t a was t h e measure o f e n h a n c e d e n e r g y u t i l i z e d by t h e c o n t r a c t i l e component ( r e c o v e r e d r e c o i l e n e r g y ) . The b e s t e s t i m a t e o f d r o p h e i g h t s f o r t h e d e p t h j u m p s , d a t a . i t e m (5) , were o b t a i n e d f r o m t h e i m p u l s e a n a l y s i s f r o m w h i c h e c c e n t r i c e n e r g y was c a l c u l a t e d f o r d a t a i t e m (3) a b o v e . EXPERIMENTAL DESIGN The s t u d y u s e d a Twoway A n a l y s i s o f V a r i a n c e (ANOVA) d e s i g n where t h e f i r s t f a c t o r was t h e t y p e o f jump w i t h t h r e e l e v e l s ( s q u a t jump, c o u n t e r m o v e m e n t jump, and d e p t h j u m p ) ; and t h e s e c o n d f a c t o r was j u m p i n g s u r f a c e w i t h two l e v e l s ("no" mat and " w i t h " m a t ) . S T A T I S T I C A L TREATMENT The h e i g h t jumped i s t h e u l t i m a t e measure o f a v e r t i c a l jump. I t was c h o s e n t o t e s t w h e t h e r t h e r e was a d i f f e r e n c e b e t w e e n t h e two j u m p i n g / l a n d i n g s u r f a c e s . A Twoway ANOVA was p e r f o r m e d on t h e " h e i g h t j u m ped" d a t a o v e r a l l t r i a l s and t e s t e d a t an a l p h a l e v e l o f 0 . 0 1 . N e x t , a t a b l e was g e n e r a t e d t o q u a n t i f y t h e p e r c e n t o f e c c e n t r i c e n e r g y u s e d as r e c o i l e n e r g y i n e a c h t y p e o f jump p e r f o r m e d o f f b o t h t y p e s o f s u r f a c e . A Twoway ANOVA was r u n on t h e e c c e n t r i c e n e r g i e s f o r t h e c o u n t e r m o v e m e n t jump and d e p t h jump e v e n t s and t e s t e d a t t h e 0 . 0 1 l e v e l . Two-sample " t " t e s t s were p e r f o r m e d on t h e d e p t h jump l o w e s t d i s p l a c e m e n t s , d r o p h e i g h t s and e c c e n t r i c e n e r g i e s t o v e r i f y as w e l l a s 20 c l a r i f y t h e d i f f e r e n c e s i n t h e s e v a r i a b l e s . The h y p o t h e s e s : H o : V'no" mat) = * ( f , w i t h " mat) A l t . : X ( » n o " m a t ) * X ( " w i t h M mat) or H . 2 2 V 3 ("no" mat) ~ 3 ("with" mat) 2 ("no" mat) r ° ( " w i t h " mat) A l t . : s / » - - » „ „ t . \ £ s / I ! . . . was t e s t e d by t h e a b o v e named s t a t i s t i c s p r o c e s s e s . 21 CHAPTER IV RESULTS AND DISCUSSION INTRODUCTION F i f t e e n f e m a l e s u b j e c t s p a r t i c i p a t e d i n t h i s s t u d y . E a c h s u b j e c t p e r f o r m e d 18 v e r t i c a l jumps f r o m a K i s t l e r F o r c e P l a t e . The jumps were a p p o r t i o n e d as f o l l o w s : s i x s q u a t j u m p s , s i x c o u n t e r m o v e m e n t j u m p s , and s i x d e p t h j u m p s . E a c h s e t o f s i x jumps were f u r t h e r s u b d i v i d e d i n t o t h r e e v e r t i c a l jumps o f f t h e f o r c e p l a t e and t h r e e o f f a 0.20 m t h i c k " a b s o r b e n t " foam j u m p i n g / l a n d i n g mat p l a c e d upon t h e f o r c e p l a t e . A r e c o r d was d e v e l o p e d o f e a c h s u b j e c t ' s t i m e i n t h e a i r ; h e i g h t jumped; g e n e r a t e d k i n e t i c e n e r g y ; e c c e n t r i c e n e r g y d e v e l o p e d f r o m l o s s i n p o t e n t i a l e n e r g y ( n e g a t i v e w o r k ) and where a p p l i c a b l e , f r o m downward d i r e c t e d k i n e t i c e n e r g y ; change i n k i n e t i c e n e r g y f o r c o u n t e r m o v e m e n t jump and d e p t h jump t r i a l s w i t h r e s p e c t t o s q u a t jump t r i a l s ( a s s umed t o be r e c o v e r e d e c c e n t r i c e n e r g y and c a l l e d r e c o i l e n e r g y ) ; and h e i g h t o f d r o p f o r e a c h d e p t h jump. The t e r m " r e c o i l e n e r g y " i s us e d i n t h i s s t u d y as an a l t e r n a t i v e e x p r e s s i o n f o r e l a s t i c e n e r g y and i n c l u d e s a l l t y p e s o f s t o r e d p o t e n t i a l e n e r g y w i t h i n t h e n e u r o m u s c u l a r c o m p l e x . R e c o i l e n e r g y , t h e r e f o r e , i n c l u d e s t h o s e n e u r o m u s c u l a r p r o c e s s e s w h i c h have t h e p o t e n t i a l t o s t o r e e n e r g y s u c h as m u s c l e s t i f f n e s s , l e v e l o f m u s c l e a c t i v a t i o n , e f f o r t l e v e l , number o f m u s c l e s u s e d , e t c . 22 The r e s u l t s and d i s c u s s i o n o f t h i s s t u d y a r e d i v i d e d i n t o t h r e e s e c t i o n s : F i r s t , a summary o f t h e d i f f e r e n c e s i n t h e f o r c e / t i m e c u r v e p r o f i l e s ' o f t h e v e r t i c a l jumps f o r t h e s q u a t , c o u n t e r m o v e m e n t and d e p t h jumps; s e c o n d , a s t a t i s t i c a l a n a l y s i s o f h e i g h t jumped; and t h i r d , a n a l y s i s o f t h e q u a n t i f i e d p e r c e n t a g e s o f e c c e n t r i c e n e r g y r e c o v e r e d as r e c o i l e n e r g y w i t h a f o l l o w - u p s t a t i s t i c a l a n a l y s i s o f d e p t h jump e c c e n t r i c e n e r g y . FORCE VS TIME CURVE PROFILES OF VERTICAL JUMPS The a n a l y s i s o f t h e jumps p e r f o r m e d i n t h i s s t u d y was b a s e d on a c c e p t e d b i o m e c h a n i c a l c o n c e p t s o f t h e movement o f t h e c e n t e r o f g r a v i t y (C o f G) d u r i n g v e r t i c a l jumps ( A . J . S p a e p e n , e t a l . , 1 9 7 5 ) . F i g u r e 1 i l l u s t r a t e s a t y p i c a l f o r c e - t i m e c u r v e o f a v e r t i c a l jump begun f r o m an e r e c t s t a n d i n g p o s i t i o n ( a c o u n t e r m o v e m e n t j u m p ) . FIGURE 1 - RECORD OF PUSH DOWN FORCE VERSUS TIME OF A VERTICAL JUMP TIME (SEC) 23 Key t o F i g u r e 1: body w e i g h t l i n e 1 = S e c t o r A = f o r c e - t i m e p r o f i l e o f c o u n t e r m o v e m e n t phase where f o r c e o f g r a v i t y i s a l l o w e d t o d o m i n a t e (C o f G moves downward). P o t e n t i a l e n e r g y i s b e i n g r e d u c e d w h i l e d o i n g n e g a t i v e work ( c a l l e d e c c e n t r i c e n e r g y i n t h i s s t u d y ) . . S e c t o r B = a r e a where t h e jumper a p p l i e s f o r c e s w h i c h e x c e e d h e r w e i g h t i n o r d e r t o s t o p t h e c o u n t e r m o v e m e n t . T h i s i s upward d i r e c t e d k i n e t i c e n e r g y (C o f G s t i l l m oving down) r e q u i r e d t o b a l a n c e l o s t p o t e n t i a l e n e r g y o f S e c t o r A i n o r d e r t o s t o p downward movement. S e c t o r C = a r e a where a p p l i e d f o r c e s d e v e l o p k i n e t i c e n e r g y w h i c h a f f e c t how h i g h t h e C o f G w i l l r i s e a f t e r t h e j u m p e r ' s f e e t l e a v e t h e j u m p i n g s u r f a c e (C o f G now moving u p w a r d ) . S e c t o r D = a r e a j u s t p r i o r t o t a k e - o f f where t h e f o r c e o f g r a v i t y e x c e e d s t h e f o r c e b e i n g a p p l i e d by t h e jumper (C o f G m o v i n g u p w a r d ) . S e c t o r E = t , = t„ = t , = p e r i o d o f t i m e when t h e j u m p e r i s i n t h e a i r . t i m e when j u m p e r ' s a p p l i e d f o r c e s a g a i n e q u a l h e r w e i g h t . t i m e when C o f G's downward movement c e a s e s and i t s upward movement b e g i n s . t i m e when j u m p e r ' s a p p l i e d f o r c e s e q u a l body w e i g h t b u t p r i o r t o h e r f e e t l e a v i n g t h e g r o u n d . t i m e j u m p e r ' s f e e t l e a v e t h e g r o u n d . t- = t i m e o f l a n d i n g . The s q u a t jump, c o u n t e r m o v e m e n t jump and d e p t h jump a l l had t o be t r e a t e d d i f f e r e n t l y d u r i n g t h e a n a l y s i s . S i n c e t h e s q u a t jump was e x e c u t e d w i t h o u t a p r e p a r a t o r y c o u n t e r m o v e m e n t , t h e s t a r t i n g p o s i t i o n o f e a c h s u b j e c t ' s C o f G was l o w e r t h a n f o r t h e c o u n t e r m o v e m e n t and d e p t h t y p e 24 of jumps. The c o m p u t e r p r o g r a m was u n a b l e t o t a k e i n t o a c c o u n t t h e e x t r a work r e q u i r e d t o r e t u r n t h e C o f G t o i t s n o r m a l l e v e l when t h e jumper i s s t a n d i n g e r e c t . I t r e a d a l l t h e g e n e r a t e d k i n e t i c e n e r g y as c o n t r i b u t i n g t o t h e h e i g h t o f r i s e o f t h e C o f G w h i l e t h e jumper was i n t h e a i r . C o n s e q u e n t l y , when t h e i n t e g r a t i o n o f t h e f o r c e v e r s u s t i m e c u r v e was u s e d t o p r e d i c t h e i g h t jumped, i t was a l w a y s o v e r e s t i m a t e d w i t h r e s p e c t t o u s i n g " t i m e i n t h e a i r " . The d e c i s i o n , t h e r e f o r e , was t o use " t i m e i n t h e a i r " as t h e p r e d i c t o r o f h e i g h t jumped w h i c h , i n t u r n , was u s e d t o q u a n t i f y k i n e t i c e n e r g y . FIGURE 2 - TYPICAL FORCE-TIME CURVE FOR SQUAT JUMP The p r e d i c t i o n o f h e i g h t jumped f r o m t h e i n t e g r a t i o n o f t h e f o r c e - t i m e c u r v e f o r t h e c o u n t e r m o v e m e n t c l o s e l y a g r e e d w i t h t h e p r e d i c t i o n d e r i v e d f r o m " t i m e i n t h e a i r " . N e v e r t h e l e s s , t i m e i n t h e a i r was used as t h e p r e d i c t o r f o r t h e h e i g h t o f r i s e o f C o f G. The d e t e r m i n a t i o n , h o w e v e r , o f l o w e s t d i s p l a c e m e n t o f C o f G ( t h e measurement f o r e c c e n t r i c e n e r g y ) was d e r i v e d f r o m t h e f o r c e - t i m e c u r v e i n t e g r a t i o n . 2 5 FIGURE 3 - TYPICAL FORCE-TIME CURVE FOR COUNTERMOVEMENT.JUMP F o r t h e d e p t h j u m p , t h e i n t e g r a t i o n o f t h e f o r c e - t i m e c u r v e u n d e r e s t i m a t e d t h e h e i g h t o f r i s e o f t h e C o f G w h e n c o m p a r e d w i t h t h a t d e r i v e d f r o m " t i m e i n t h e a i r " . T h i s wa s e x p e c t e d s i n c e t h e way t h e s u b j e c t s s t e p p e d o f f t h e 0 . 4 0 ra h i g h b o x wa s p o o r l y c o n t r o l l e d . E a c h s u b j e c t s t a r t e d h e r j u m p by s t e p p i n g o u t a n d down o f f t h e b o x . T h e i r h e i g h t s o f d r o p u n d e r t h e i n f l u e n c e o f g r a v i t y wa s l e s s t h a n t h e p l a n n e d 0 . 4 0 m. T h e p r o g r a m , t h e r e f o r e , w a s c o m p u t i n g m o r e d o w n w a r d k i n e t i c e n e r g y t h a n t h e j u m p e r a c t u a l l y d e v e l o p e d ( f i g u r e 4 ) . A c t u a l h e i g h t o f d r o p was e s t i m a t e d by f e e d i n g v a r i o u s d r o p h e i g h t s ( t o n e a r e s t 0 . 0 0 1 m) i n t o t h e c o m p u t e r ' s i n t e g r a t i o n p r o g r a m u n t i l i t p r e d i c t e d a h e i g h t j u m p e d t h a t c l o s e l y a g r e e d w i t h h e i g h t d e r i v e d b y " t i m e i n t h e a i r " . T h e a v e r a g e d r o p h e i g h t c o m p u t e d w a s . 3 m f o r t h e " n o " m a t t r i a l s a n d . 2 8 m f o r t h e " w i t h " m a t t r i a l s . T h e s e t w o h e i g h t s o f d r o p w e r e u s e d t o c o m p u t e d o w n w a r d d i r e c t e d k i n e t i c e n e r g y . A s d o n e f o r t h e c o u n t e r m o v e m e n t j u m p t r i a l s , t h e p r o g r a m a l s o p r e d i c t e d l o w e s t d i s p l a c e m e n t o f C o f G ( t i m e t 0 - s e e f i g u r e 1 ) w i t h r e s p e c t t o h e i g h t 2 6 of C of G at the time of l a n d i n g on the f o r c e p l a t e . E c c e n t r i c energy f o r depth jumps was the sum of downward d i r e c t e d k i n e t i c energy and l o s s of p o t e n t i a l energy d e r i v e d from l o w e s t d i s p l a c e m e n t of C of G. As done p r e v i o u s l y f o r the squat and countermovement jumps, "time i n the a i r " was used to compute h e i g h t of r i s e of C of G which, i n t u r n , was used to generate the v a l u e f o r k i n e t i c energy. FIGURE A - TYPICAL FORCE-TIME CURVE FOR DEPTH JUMP . STATISTICAL ANALYSIS OF HEIGHT JUMPED The observed and d e r i v e d data by t r i a l s f o r each s u b j e c t i s l i s t e d i n Appendix D. Appendix E c o n t a i n s each s u b j e c t ' s averaged t r i a l d a t a . The c e l l means f o r the s u b j e c t ' s observed data over a l l t r i a l s (N = 2 7 0 ) f o r h e i g h t jumped are c o n t a i n e d i n Tab l e 1. Table 2 i s the 2 x 3 ANOVA t a b l e f o r the s u b j e c t s ' h e i g h t of jump over a l l t r i a l s (2 jump s u r f a c e s x t h r e e types of jumps). 27 TABLE 1 - MEANS FOR HEIGHT JUMPED OVER ALL TRIALS (N = 45 PER CELL) SJ CJ DJ HT JMPD (cm) HT JMPD (cm) HT JMPD (cm) TOTALS X = "NO" MAT SD = 25.54 3.576 29.3 3.179 27.79 4.205 27.54 3.965 X = "WITH" MAT SD = 19.72 3.378 22.78 3.862 19.41 4.224 20.64 4.103 X = TOTALS SD = 22.63 4.53 26.04 4.808 23.6 .5.941 24.09 5.308 Key: SJ = Squat Jump CJ = Countermovement Jump DJ = Depth Jump TABLE 2 - TWOWAY ANALYSIS OF VARIANCE FOR HEIGHT JUMPED OVER ALL TRIALS (N = 270) SOURCE DF SS MS F P TYPE OF JUMP- 2 554 .9 277 . 5 19.68 < 0.001 JUMP SURFACE 1 3217 .5 3217. 5 228.19 < 0.001 INTERACTION 2 78 .7 39. 4 2.79 > 0.05 ERROR 264 3728 .6 14. 1 TOTAL 269 7579 .8 The c r i t i c a l F f o r 2 and 264 degrees of freedom i s 3.03 a t the .05 and 4.7 at the .01 l e v e l of s i g n i f i c a n c e . C r i t i c a l F f o r 1 and 264 degrees of freedom i s 3.88 and 6.75 f o r .05 and .01 l e v e l of s i g n i f i c a n c e r e s p e c t i v e l y . Table 2 28 shows s i g n i f i c a n c e between the t h r e e types of jumps and between the two jumping s u r f a c e s . The i n t e r a c t i o n i s n o n s i g n i f i c a n t . The F v a l u e of 228.19 f o r the t e s t between the two s u r f a c e s , shows a d i f f e r e n c e p < 0.001 l e v e l of s i g n i f i c a n c e . T h i s i n d i c a t e s t h a t the 0.20 m absorbent mat absorbs some of the k i n e t i c energy and/or d i s s i p a t e s the s t o r e d r e c o i l energy which i s b e l i e v e d to be d e r i v e d from a c c r u e d e c c e n t r i c energy. ECCENTRIC ENERGY ANALYSIS Asmussen and Bonde-Petersen (1974) posed the q u e s t i o n , "Can muscles absorb and t e m p o r a r i l y s t o r e m e c h a n i c a l energy i n the form of e l a s t i c energy f o r l a t e r r e - u s e ? " T h e i r p l a n was to determine the amount of u s e a b l e e c c e n t r i c energy s t o r e d as r e c o i l energy d u r i n g the e c c e n t r i c c o n t r a c t i o n and which was f r e e d i mmediately t h e r e a f t e r , adding to the amount of energy m a n i f e s t e d by the c o n c e n t r i c c o n t r a c t i o n . The squat jump was c o n s i d e r e d the b a s e l i n e measure of the c o n t r a c t i l e component's c a p a b i l i t y . The g a i n s i n k i n e t i c energy d u r i n g the countermovement and depth jumps over t h a t r e a l i z e d by the squat jump was shown to be the r e c o i l energy s t o r e d d u r i n g the p r e p a r a t o r y countermovement phase of the jumps. The f o l l o w i n g f o r m u l a q u a n t i f i e d the r e c o i l energy as a percentage of e c c e n t r i c energy: <7 p • r> I n c r e a s e i n KE „ . n n , \ % E c c e n t r i c Energy = —: 5 X 100 (7) 5 7 E c c e n t r i c Energy 29 T h e i r study showed a r e c o v e r y r a t e of r e c o i l energy of 22.9% f o r the countermovement jumps and 10.5% and 13.2% f o r depth jumps performed from h e i g h t s of 0.404 ra and 0.233 m r e s p e c t i v e l y . T h i s study a c h i e v e d 13.4% f o r the countermovement and 4.8% f o r the depth jump o f f a 0.40 m h i g h box ( t h e drop h e i g h t was c a l c u l a t e d to be 0.3 ra). T h i s i n v e s t i g a t o r cannot e x p l a i n why h i s r e s u l t s are 6% to 9% lower than the Asmussen/Bonde-Petersen s t u d y . There i s agreement, however, i n t h a t an i n c r e a s e i n k i n e t i c energy i s m a n i f e s t e d i n jumps preceded by. an e c c e n t r i c energy phase. TABLE 3 - SUMMARY OF MEANS TYPE OF JUMP #1 HEIGHT JUMPED (cm) #2 KINETIC ENERGY ( J ) #3 EC'NTRIC ENERGY (J ) #4 ENERGY CHANGE ( J ) #5 DROP HEIGHT (cm) SJ X "NO" MAT SD SJ X "WITH" MAT SD 25.54 3.346 19.72 3.137 166.74 19.975 128.5 2 16.758 C J Y "NO" MAT SD CJ X "WITH" MAT SD 29.3 3. 127 22.78 3.710 191.93 24.165 148.75 22.84 188.38 26.672 175.77 22.712 25.19 12.563 20.23 17.572 DJ X "NO" MAT SD DJ X "WITH" MAT SD 27.79 4.059 19.41 4.031 181.82 26.988 126.65 24.328 315.54 52.421 362 .0 64.561 15.08 15.912 -1.87 19.667 29.99 3.472 28.11 5.036 Key: SJ = Squat Jump CJ = Countermovement Jump DJ = Depth Jump 30 T h i s s t u d y does n o t show where t h i s e n h a n c e d e n e r g y was d e r i v e d . However, i t i s r e a s o n a b l e and c o n s i s t e n t w i t h p r e v i o u s r e s e a r c h t o a t t r i b u t e i t t o s t o r e d r e c o i l e n e r g y d e r i v e d f r o m t h e e c c e n t r i c e n e r g y b r o u g h t a b o u t by t h e e c c e n t r i c c o n t r a c t i o n d u r i n g t h e p r e p a r a t o r y c o u ntermovement phase o f t h e j u m p i n g a c t . T a b l e 3 above g i v e s a s u m m a r y o f t h e s t u d y ' s means by t y p e o f jump and l a n d i n g / j u m p i n g s u r f a c e . T a b l e 4 g i v e s a summary o f e n e r g y g a i n s a n a l y s i s . T a b l e s 5 and 6 show t h e r e s u l t s o f a Twoway ANOVA on e c c e n t r i c e n e r g y . T a b l e 4 shows s i m i l a r r e c o v e r y o f r e c o i l e n e r g y f o r t h e c o u n t e r m o v e m e n t jump , . „ . ( 1 1 . 3 % ) as was J r ( w i t h mat) a c h i e v e d by t h e c o u n t e r m o v e m e n t jump ,„ ,, _ N ( 1 3 . 4 % ) . 3 ( no mat) . T h i s s h o u l d be no s u r p r i z e . The a b s o r b e n t j u m p i n g / l a n d i n g mat was d e p r e s s e d u n d e r t h e w e i g h t o f t h e jumper s t a n d i n g on t h e mat and any l o s s of k i n e t i c e n e r g y was p r o b a b l y due t o a b s o r p t i o n by t h e mat i t s e l f . T h i s i s c o n f i r m e d by t h e d i f f e r e n c e s i n k i n e t i c e n e r g y o f t h e s q u a t jump and c o u n t e r m o v e m e n t jump v e r s u s t h e two j u m p i n g s u r f a c e s . The k i n e t i c e n e r g y f o r t h e c o u n t e r m o v e m e n t ( " w i t n " m a t ) w a S 7 7 . 3 % o f t h a t g e n e r a t e d by t h e c o u n t e r m o v e m e n t ,„ „ _ N • . ( n o mat) ( 1 9 1 . 9 3 J vs 148.38 J ) . T h i s a g r e e d w i t h t h e d i f f e r e n c e f o r t h e s q u a t jump p e r f o r m e d o f f t h e same two s u r f a c e s ( 7 7 . 1 % ) ( 166.74 J vs 128.52 J ). E a ch jumper was a b l e t o p e r f o r m h e r c o u n t e r m o v e m e n t jumps i n a n o r m a l manner w i t h no d a mpening o f t h e e c c e n t r i c c o n t r a c t i o n b e i n g e v i d e n t . 31 TABLE 4 - SUMMARY OF ENERGY GAINS ANALYSIS ("NO" MAT) TYPE OF JUMP ECCENTRIC ENERGY ( J ) KINETIC ENERGY ( J ) ENERGY CHANGE ( J ) . % ECCENTRIC ENERGY * SQUAT JUMP COUNTERMOVEMENT JUMP DEPTH JUMP 0 188.38 315.54 166.74 191.93 181.82 25.19 15.08 13.4% * 4.8% • • . ("WITH" MAT) SQUAT'JUMP COUNTERMOVEMENT JUMP DEPTH JUMP 0 175.77 362.00 128.52 148.38 126.65 19.86 -1.87 11.3% -0.5% % E c c e n t r i c Energy P e r c e n t E c c e n t r i c Energy Change i n K i n e t i c Energy ^ ^ Q Q E c c e n t r i c Energy The percent of e c c e n t r i c energy r e c o v e r e d i n the c o n c e n t r i c c o n t r a c t i o n . The data f o r the depth jump ,„ . t U f t _ >. was q u i t e r J r ( w i t h mat) ^ d i f f e r e n t . Recovery of any s t o r e d energy was e s s e n t i a l l y z e r o (-0.5%). T h i s was ex p e c t e d . The absorbent l a n d i n g / j u m p i n g mat was expected to dampen the l a n d i n g a f t e r the drop from the 0.40 m box. T h i s a p p a r e n t l y o c c u r r e d . In a d d i t i o n , T a b l e 3 shows a 14.7% i n c r e a s e i n e c c e n t r i c energy (315.54 J vs 362.0 J ) f o r the " w i t h " mat e v e n t s . S i n c e the average drop h e i g h t was l e s s than the depth jump ( » n o " m a t ) ( 0 . 2 8 m vs 0.3 i n ) , t h e l o w e s t d i s p l a c e m e n t o f t h e C of G must have i n c r e a s e d s i g n i f i c a n t l y f o r t h i s t o o c c u r . The a v e r a g e l o w e s t d i s p l a c e m e n t o f t h e C o f G f o r d e p t h jumps ("no" mat) a n d d e p t h j U m p S ( " w i t h " mat) w a s - ° - 1 8 m and -0.2 7 m r e s p e c t i v e l y . T h i s d e e p e r knee bend by t h e j u m p e r s meant an i n c r e a s e i n s t r e t c h e d l e n g t h o f t h e a c t i v e m u s c l e s b u t a d e c r e a s e d r a t e o f s t r e t c h . Komi and Bosco ( 1 9 7 8 ) i d e n t i f i e d r a t e o f s t r e t c h as t h e d o m i n a n t f a c t o r i n g e n e r a t i n g r e c o i l e n e r g y . A p p a r e n t l y , t h e j u m p e r ' s r e a c t i o n t o l a n d i n g on t h e a b s o r b e n t s u r f a c e c o m p l i m e n t e d TABLE 5 - MEANS OF ECCENTRIC ENERGY FROM SUBJECT AVERAGED DATA (N = 15 PER CELL) CJ DJ ECCENTRIC ENERGY ( J ) ECCENTRIC ENERGY ( J ) TOTALS X = "NO" MAT SD = 188.38 26.672 315.54 52.421 251.96 76.496 X = "WITH" MAT SD = 175.77 22.712 362 .0 64.561 268.88 105.973 X = TOTALS SD = 182.08 25.171 338.77 62.426 260.42 91.255 Key: S J CJ DJ S q u a t Jump Countermovement Jump D e p t h Jump 33 any dampening e f f e c t s o f t h e a b s o r b e n t l a n d i n g / j u m p i n g s u r f a c e . A Twoway ANOVA was p e r f o r m e d on e c c e n t r i c e n e r g y o v e r two s u r f a c e s and two t y p e s of jumps (Countermovement and D e p t h Jump) t o v e r i f y t h e s e o b s e r v a t i o n s . See T a b l e 5 a bove and T a b l e 6 b e l o w . TABLE 6 - TWOWAY ANALYSIS OF VARIANCE FOR ECCENTRIC ENERGY (C o u n t e r m o v e m e n t Jumps and D e p t h Jumps) SOURCE DF SS MS F . I TYPE OF JUMP 1 368282 368282 180 89 < 0 001 JUMP SURFACE 1. 4295 4295 2 11 > 0 1 INTERACTION 1 13085 13085 6 43 < 0 025 ERROR 56 1140071 2036 TOTAL 59 74662 The c r i t i c a l F f o r 1 and 56 d e g r e e s of f r e e d o m a t t h e 0.01 l e v e l o f s i g n i f i c a n c e i s 7.1. The Twoway ANOVA shows s i g n i f i c a n c e b etween t h e two t y p e s o f jumps. T h i s was e x p e c t e d s i n c e t h e downward k i n e t i c e n e r g y d e v e l o p e d by t h e d r o p f r o m t h e 0.40 m box i s p a r t o f t h e e c c e n t r i c e n e r g y e q u a t i o n f o r d e p t h jump e v e n t s , w h e r e a s t h i s i s n o t t h e c a s e f o r t h e c o u n t e r m o v e m e n t jumps. A l t h o u g h n o t s i g n i f i c a n t a t t h e 0.01 l e v e l , t h e i n t e r a c t i o n e f f e c t does show s t r o n g e v i d e n c e o f o t h e r c o n t r i b u t i n g f a c t o r s ' . The " t " t e s t i n t a b l e 9 b e l o w shows s i g n i f i c a n c e (p < 0.001) c o n f i r m i n g t h a t l o w e s t d i s p l a c e m e n t o f t h e C of G i n t h e d e p t h jumps i s a m a j o r c o n t r i b u t o r t o t h e i n c r e a s e d e c c e n t r i c e n e r g y of t h e d e p t h J u r a P ( " w i t h " mat) ' w n : i - c n i n t u r n > s u g g e s t s t h a t t h i s a l s o c o n t r i b u t e d t o t h e d i s s i p a t i o n o f r e c o i l e n e r g y shown i n t a b l e 4. 34 TABLE 7 - TWOSAMPLE T TEST FOR ECCENTRIC ENERGY ' N MEAN STDEV DJ,„ . 45 (. no mat; 315.54 J 56.546 D J ( " w i t h " mat) 4 5 361.00 J 67.791 t = 3.53 p < 0.001 TABLE 8 - TWOSAMPLE T TEST FOR DROP HEIGHT N MEAN STDEV D J ( " n o " mat) 4 5 29.99 cm 4.229 D J ( " w i t h " mat) 4 5 28.11 cm 5.357 t = 1.85 p > 0.025 TABLE 9 - TWOSAMPLE.T TEST FOR LOWEST DISPLACEMENT N MEAN STDEV D J ( " n o " mat) 45 -17.87 cm 4.165 D J ( " w i t h " mat) 45 -26.78 cm 4.835 t = 9.37 p < 0.001 The r e s u l t s of the e c c e n t r i c energy a n a l y s i s r e j e c t s the N u l l H y p o t h e s i s , "There i s no d i f f e r e n c e i n the s t o r a g e of r e c o i l energy i n a normal e c c e n t r i c c o n t r a c t i o n versus a slowed e c c e n t r i c c o n t r a c t i o n " . In the depth jump event the evid e n c e from t h i s study shows t h a t no g a i n s i n e c c e n t r i c energy are r e a l i z e d from downward.kinetic energy when performed on an absorbent l a n d i n g / j u m p i n g s u r f a c e , whereas f o r the countermovement jumps t h e r e are g a i n s which compare f a v o r a b l y w i t h jumps o f f a normal j u m p i n g / l a n d i n g s u r f a c e . F u r t h e r , i n the case of depth jumps from 0.40 m t h e r e i s evi d e n c e i d e n t i f y i n g i n c r e a s e d knee bend i n d i c a t i n g a l o n g e r 35 ( s l o w e r ) a b s o r p t i o n p e r i o d from' t h e a p p r o x i m a t e 0.40 m-drop o n t o t h e a b s o r p t i v e l a n d i n g / j u m p i n g s u r f a c e . T h e r e f o r e , i n t h e c a s e o f c o u n t e r m o v e m e n t jumps t h e 0 . 20 m t h i c k foam mat a b s o r b s k i n e t i c e n e r g y w h i l e n o t i n h i b i t i n g t h e r e c o v e r y o f s t o r e d r e c o i l e n e r g y . I n t h e d e p t h jump c a s e t h e a b s o r b e n t mat d i s s i p a t e s k i n e t i c e n e r g y as w e l l as s h o w i n g no o v e r a l l g a i n i n e n e r g y w i t h r e s p e c t t o t h e s q u a t jump ( t t w ^ t n t i m a t ) « The f a i l u r e t o r e a l i z e g a i n s i n k i n e t i c e n e r g y i s a t t r i b u t e d t o t h e dampening o f s t o r e d r e c o i l e n e r g y t h r o u g h t h e s l o w i n g , o f t h e e c c e n t r i c c o n t r a c t i o n v i a i n c r e a s e d knee bend. A l t h o u g h t h e r e i s no e v i d e n c e , i t i s a l s o l i k e l y t h a t e c c e n t r i c e n e r g y was a b s o r b e d by t h e 0.20 m foam mat f u r t h e r d e g r a d i n g t h e s t o r a g e o f r e c o i l e n e r g y . From t h e e v i d e n c e i n t h i s s t u d y t h e use o f t h i c k mats f o r p l y o m e t r i c jump t r a i n i n g w i l l d e g r a d e t h e r e c o v e r y o f s t o r e d r e c o i l e n e r g y , t h e r e b y p o s s i b l y a l l o w i n g t h e s e l e c t i v e t r a i n i n g o f t h e c o n t r a c t i l e component o f human m u s c l e . / REFERENCES Asmussen, E. and Bonde-Petersen, F. Storage Energy i n S k e l e t a l Muscles i n Man. Acta  Scand. 91: 385-392, 1974. o f E l a s t i c P h y s i o l . Asmussen, E. and Bonde-Petersen, F. Apparent E f f i c i e n c y an Storage of E l a s t i c Energy i n Human Muscles During E x e r c i s e . Acta P h y s i o l . Scand. 92: 537-545, 1974. A s t r a n d , P. and K. Rodohl. 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Cavagna, G. A., B. Dusman and R. M a r g a r i a . P o s i t i v e Work Done by a P r e v i o u s l y S t r e t c h e d M u s c l e . J o u r n a l of  A p p l i e d P h y s i o l o g y , 24: 21-32, 1968. Cavagna, G. A., L. Komarek, G. V i t t e r i o and R. Margaria'. Power Output of the P r e v i o u s l y S t r e t c h e d Muscle. M e d i c i n e and S p o r t , V o l . 6: Biomechanics I I , 159-167, 1971. Chu, Donald C. P l y o m e t r i c s : The L i n k Between S t r e n g t h and Speed. NSCA J o u r n a l , A p r i l - M a y , 1983, 20-21. Edman, K. A. P., G. E l z i n g a and M. I . M. Noble. Enhancement of M e c h a n i c a l Performance by S t r e t c h D u r i n g T e t a n i c C o n t r a c t i o n s of V e r t e b r a t e S k e l e t a l Muscle F i b r e s . ' J o u r n a l of P h y s i o l o g y , 281: 139-155, 1978. Hakkinen, K. and P. Komi. A l t e r a t i o n s of M e c h a n i c a l C h a r a c t e r i s t i c s of Human S k e l e t a l Muscle During S t r e n g t h T r a i n i n g . European J o u r n a l of A p p l i e d P h y s i o l o g y , 50: 161-172, 1983. Komi, P. and C. Bosco. U t i l i z a t i o n of S t o r e d E l a s t i c Energy i n Leg E x t e n s o r Muscles by Men and Women.. M e d i c a l  S c i e n c e i n S p o r t s , 1 0 ( 4 ) : 261-265, 1978. Kreighbaum, E. and K. M. B a r t h e l s . Biomechanics - A  Q u a l i t a t i v e Approach For S t u d y i n g Human Movement. M i n n e a p o l i s , M i n n e s o t a : Burgess P u b l i s h i n g Co., 1985. Luhtanen, P. and P. Komi. Segmental C o n t r i b u t i o n to Forces i n V e r t i c a l Jump. European J o u r n a l of A p p l i e d  P h y s i o l o g y , 38: 181-188, 1978. Morgan, D. L., U. Proske and D. Warren. Measurements of Muscle S t i f f n e s s and the Mechanism of E l a s t i c Storage of Energy i n Hopping Kangaroos. J o u r n a l of P h y s i o l o g y , 282: 253-261, 1978. 39 P e t e r s e n , F., H. G r a n d a l , J . Hansen and N. Hvid. The E f f e c t of V a r y i n g the Number of Muscle C o n t r a c t i o n s on Dynamic Muscle T r a i n i n g . I n t e r n . Z. Angew. P h y s i o l . 18: 468, 1961. R a d c l i f f e , J . C. and R. C. F a r e n t i n o s . P l y o m e t r i c s - _ E x p l o s i v e Power T r a i n i n g . B o u l d e r , C o l o r a d o : Exer T e c h n i c s P u b l i s h e r s , 1984. Spaepen, A. J . , E. J . Willems and D. J . D a l y . V e r t i c a l Jump. Hermes, V o l . 9, I s s u e 5, 437-444, 1975. 40 APPENDIX A INFORMED CONSENT FORM 41 CONSENT TO A BIOMECHANICAL EVALUATION FORM You w i l l be asked to perform i n the UBC Human Mechanics L a b o r a t o r y v a r i o u s v e r t i c a l jumping movements which w i l l be measured e l e c t r i c a l l y on a K i s t l e r Force P l a t e . You w i l l a l s o have your h e i g h t and weight measured. The v e r t i c a l jumping movements you w i l l be asked to perform w i l l be to jump d i r e c t l y o f f the Force P l a t e , as w e l l as o f f a 64 x 44 x 20 c e n t i m e t e r foam pad l a i d on top of the Force P l a t e . O n e - t h i r d of the jumps w i l l be performed immediately a f t e r jumping from a 40 c e n t i m e t e r (15.75 i n . ) h e i g h t . You w i l l wear r e g u l a r gym a t t i r e , l e s s s w e a t s u i t o v e r c l o t h i n g . In s i g n i n g t h i s consent form you s t a t e t h a t you have read, and understood the above s t a t e m e n t s . You e n t e r the biomechanics e v a l u a t i o n w i l l i n g l y and you may withdraw AT  ANY TIME w i t h o u t p e n a l t y or d i s c r i m i n a t i o n . CONSENT I have read the above comments and wis h to proceed w i t h the b i o m e c h a n i c a l e v a l u a t i o n . Date S i g n a t u r e Witness ; I hereby consent to and a u t h o r i z e the use and r e p r o d u c t i o n of any photographs and Force P l a t e r e c o r d s taken of me d u r i n g t h i s b i o m e c h a n i c a l e v a l u a t i o n f o r s c i e n t i f i c and r e s e a r c h purposes, w i t h the u n d e r s t a n d i n g t h a t my i d e n t i t y w i l l be kept c o n f i d e n t i a l . D a t e _ S i g n a t u r e Witness '  42 APPENDIX B SPECIFICATIONS FOR "ABSORBENT" FOAM JUMPING/LANDING PAD 43 SPECIFICATIONS FOR "ABSORBENT" FOAM JUMPING/LANDING PAD GENERAL The q u a l i t y of foam i s determined by the amou-nt of foam (by weight) poured per c u b i c f o o t . The normal range i s one (1) to t h r e e (3) pounds (0.45 to 1.35 kg) of foam per c u b i c f o o t (0.028 c u b i c m e t e r ) . Foam pads have a " f i r m n e s s " index d e f i n i n g the compression q u a l i t i e s of the foam. For example: #30 = S o f t #40 = Medium Fi r m #50 = Very F i r m The " f i r m n e s s " number r e p r e s e n t s the pounds p r e s s u r e per square f o o t r e q u i r e d to press the foam down one (1) i n c h ( i . e . , 40 pounds (18.14 kg) p r e s s u r e per square f o o t (0.09 square meter) w i l l p r e s s the foam down fr o m ' f o u r (4) i n c h e s (0.102 m)" to th r e e (3) i n c h e s (0.076 m)). SPECIFICATIONS Q u a l i t y S p e c i f i c a t i o n Number f o r 0.64 x 0.44 x 0.20 m pad used i n " E l i m i n a t i o n of Muscle R e c o i l C o n t r i b u t i o n i n V e r t i c a l Jumping" s t u d y : 1 2 3 6 Where 12 = 1.2 pounds (0.54 kg) foam per c u b i c f o o t (0.028 c u b i c m e t e r ) , and 36 = Firmness Index (36 pounds (16.33 kg) w i l l compress foam 1 i n c h (0.0254 m) per square f o o t (0 .093 ra)). The foam i s made o f : Pri m a r y Chemicals - 60% P o l y o l , 30% Toluene D i - i s o c y a n a t e . Secondary Chemicals - Water, Fr e o n , S i l i c o n e s , C a t a l y s i s , T i n and Amine. 44 APPENDIX C INDIVIDUAL DATA I N D I V I D U A L S ' V I T A L S T A T I S T I C S AGE, HEIGHT AND WEIGHT SUBJ AGE HEIGHT WEIGHT # ( y r s ) (m) (kg) 1 17.3 1.83 67.82 2 17.3 1.76 67.34 3 17.25 1.72 56.66 4 18.2 1.76 58.84 5 18.5 1.76 62.25 6 17.3 1.72 72.78 7 16.9 1.8 . 65.57 8 17.25 1.77 • 68.84 9 16.0 1.81 75.1 10 17.8 1.72 65.23 11 21.8 1.73 76.88 12 22.6 1.75 69.69 13 24.1 1.71 59.42 14 20.0 1.78 70.44 .15 18.9 1.71 66.06 X 18.75 1.755 66.861 SD 2.351 0.038 5.85 SE 0.607 0.01 1.511 APPENDIX D SUBJECT'S OBSERVED DATA (TYPE OF JUMP x TRIAL) SQUAT JUMPS SUBJ TRIAL AIR # # TIME ( s e c ) 1 1 0.415 2 0.405 3 0.415 2 1 0.467 2 0.491 3 0.461 3 1 0.506 2 0.526 3 0.536 4 1 0.423 2 0.443 3 0.433 5 1 0.451 2 0.453 3 0.473 6 1 0.429 2 0.439 3 0.429 7 1 0.453 2 0.443 3 0.412 8 1 0.46 2 0.469 3 0.469 9 1 0.412 2 0.402 3 0.392 10 1 0.45 2 0.45 3 0.48 11 • 1 0.441 2 0.461 3 0.491 12. 1 0.47 2 0.47 3 0.49 13 1 0.46. 2 0.45 3 0.489 14 1 0.442 2 0.442 3 0.462 15 •1 0.472 2 0.462 3 0.472 ("NO" MAT) #1 n . HEIGHT KINETIC JUMPED ENERGY (cm) ( J ) 21.16 140.78 20.14 133.99 21.16 140.78 26.69 176.32 29.56 195.27 26.05 172.09 31.41. 174.59 33.97 188.82 35.29 196.15 21.94 126.64 24.08 139.00 22.99 132.70 24.93 152.24 25.13 153.46 27.42 167.45 22.58 161.22 23.65 168.85 22.58 161.22 25.13 161.65 24.03 154.57 20.86 134. 18 25.98 175.45 26.98 182 .20 26.98 182.20 20.86 153.68 19.86 146.32 18.88 139.10 24.88 159.21 24.88 159.21 28.31 181.16 23.84 179.80 26.05 196.47 29.56 222.94 27.09 185.20 27.09 185.20 29.44 201.27 25.19 146.84 24.78 144.45 29.38 171.26 23.93 165.36 23.93 165.36 26.16 180.77 27.31 176.98' 26.16 169.53 31.06 201.28 X SD SE 25.541 3.576 0.533 166.738 21.703 3.235 SQUAT JUMPS ("WITH" MAT) #1 #2 SUBJ TRIAL AIR HEIGHT KINETIC # #• • TIME JUMPED ENERGY ( s e c ) (cm) ( J ) 1 1 0.321 2 0.351 3 0.371 2 1 0. 39 2 0.43 3 0.42 3 1 0.477 2 0.467 3 0.477 4 1 0.389 2 0.389 3 0.38 5 1 0.403 2 0.423 3 0.433 .6 1 0.372 2 0.382 3 0.392 7 1 0.359 2 0.429 3 0 .339 8 1 0.423 2 0.433 3 0.423 9 1 0.379 2 0.409 3 0.389 10 1 0.349 2 • 0.359 3 0.389 11 1 0.39 2 0.372 3 0.372 12 1 0.423 2 0.433 3 0.402 13 1 0.44 2 0.44 3 0.419 14 1 0.39 2 0.39 3 0.39 15 1 0.389 2 0.399 •3 0.389 X SD SE 12 .61 83 .90 15 .08 100 .33 16 .85 112 .11 18 .69 123 .47 22 .72 150 .09 21 .67 143 .15 27 .86 154 .85 26 .69 148 .34 27 .86 154 .85 18 .54 107 .02 18 .54 107 .02 17 .74 102 .40 19 .94 121 .77 21 .98 134 .23 23 .04 140 .07 16 .99 121 .30 17 .92 127 .94 18 .88 134 .80 15 .83 101 .83 22 .58 145 .24 14 .12 90 .83 21 .89 147 .83 22 .95 154 .99 21 .89 147 .83 17 .64 129 .96 20 .53 151 .25 18 .58 136 .89 14 .96 95 .73 15 .83 101 .30 18 .58 118 .90 18 .61 140 .36 16 .96 127 .91 16 .96 127 .91 21 .89 149 .65 22 .95 156 .90 19 .78 135 .23 23 .69 138 .09 23 .69 138 .09 21 .54 125 .56 18 .65 128 .88 18 .65 128 .88 18 .65 128 .88 18 .54 120 .15 19 .50 126 .37 18 .54 120 .•15 19 .724 128 .516 3 .378 18 .818 0 .504 2 .805 COUNTERMOVEMENT JUMPS ("NO" MAT) #1 #2 #3 SUBJ TRIAL AIR HEIGHT KINETIC LOWEST ECCENTRIC # # . TIME JUMPED ENERGY DSPLCMNT ENERGY (sec) (cm) ( J ) (cm) ( J ) 1 1 0.433 22.95 152.69 -28.77 191.41 2 0.423 21.89 145.63 -26.72 177.77 3 0.443 24.03 159.87 -26.79 178.23 2 1 0.504 31.09 205.38 -27.20 179.68 2 0.504 31.09 205.38 -28.09 185.56 3 0.514 32.35 213.70 -20.01 191.64 3 1 0.513 32.22 179.08 -26.54 147.51 2 0.533 34.79 193.36 -24.93 138.56 3 0.543 36.12 200.75 -29.58 164.41 4 1 0.45 24.83 143.32 -29.85 172.29 2 0.45 24.83 143.32 -31.68 182.86 3 0.46 25.95 - 149.78 -31.58 182.28 5 1 0.483 28.59 174.60 -28.51 174.11 2 0.483 28.59 174.60 -26.29 160.55 3 0.481 28.37 173.26 -29.29 178.87 6 1 0.473 27.42 195.78 -33.99 242.69 2 0.453 25.13 179.43 -32.62 232.91 3 0.473 27.42 195.78 -31.14 222.34 7 1 0.492 29.68 190.90 -32.88 211.48 2 0.492 29.68 190.90 -38.03 244.61 3 0.482 28.48 183 .18 -30.43 195.73 8 1 0.492 29.68 200.43 -30.55 206.30 2 0.502 30.90 208.67 -30.52 206.10 3 0.522 33.42 225.69 -32.37 218.60 9 1 0.469 26.93 198.39 -19. 14 141.00 2 0.479 28.08 206.87 -21.35 157.29 3 0.459 25.79 190.00 -22.87 168.48 10 1 0.493 29.80 190.69 -24.64 157.67 2 0.473 27.42 175.46 -29.21 186.92 3 0.493 29.80 190.69 -26.17 167.46 11 1 0.479 28.08 211.78 -20.11 151.67 2 0.492 29.74 224.30 -19.80 149.33 3 0.492 29.74 224.30 -20.82 157.02 12 1 0.523 33.49 228.97 -32.33 221.04 2 0.523 33.49 228.97 -32.84 224.53 3 0.523 33.49 228.97 -33.75 230.75 13 1 0.48 28.20 164.38 -35.94 209.49 2 0.489 29.38 171.26 -33.64 196.09 3 0.48 28.20 164.38 . -36.06 210.19 14 1 0.49 29.44 203.43 -26.26 181.46 2 0.49 ' 29.44 203.43 -27.53 190.23 3 0.49 29.44 203.43 -23.98 165.70 15 1 0.512 32.15 208.33 -27.06 175.53 2 0.522 33.42 216.56 -35.88 232.50 3 0.522 33.42 216.56 -33.43 216.63 X SD SE 29.299 191.925 3.179 24.296 0.474 3.622 -28.693 188.384 4.756 28.325 0.709 4.222 COUNTERMOVEMENT JUMPS ("WITH" MAT) . #1 . #2 #3 SUBJ TRIAL AIR HEIGHT KINETIC LOWEST ECCENTRIC # # TIME JUMPED ENERGY DSPLCMNT ENERGY (s e c ) (cm) ( J ) . (cm) ( J ) 1 1 0.407 20.30 135.06 -24.22 161.14 2 0.387 18.32 121.88 -26.60 183.36 3 0.403 19.90 132.40 -25.97 172.78 2 1 0.446 24.37 160.99 -25.46 168.19 2 0.466 26.64 175.98 -30.81 203.54 3 0.496 30.22 199.63 -29.12 192 .37. 3 1 0.493 29.80 165.63 -26.68 148.29 2 0.493 29.80 165.63 -26.42 146.84 3 0.503 31.03 172.47 -28.84 160.29 4 1 0.390 18.65 107.65 -26.45 152.67 2 0.390 18.65 107.65 -29,92 172.70 3 0.400 19.62 113.25 -30.43 175.64 5 1 0.441 23.84 145.59 -31.62 193.41 2 0.412 20.86 127.39 -25.12 153.41 3 0.433 22.95 140.16 -29.08 177.59 6 1. 0.411 20.74 148.08 -25.08 179.09 2 0.40i 19.74 140.94 -24.49 174.86 3 0.401 19.74 140.94 -24.14 172.36 7 1 0.361 15.99 102.85 -20.37 131.02 2 0.391 18.76 120.66 -24.35 156.62 3 0.431 22.81 146.71 -21.98 141.38 8 1 0.419 21 . 50 145.19 -26.33 177.81 2 0.429 22.54 15 2.21 -21.92 148.03 3 0.419 21 . 54 145.46 -24,74 167.07 9 1 0.380 17.71 130.47 -25.44 187.42 2 0.380 17.71 130.47 -23.25 171 .28 3 0.392 18.84 138.79 -21 .9.0 161 .34 10 1 0.400 19.54 125.04 -27.05 173.09 2 0.411 20.70 132.46 -24.92 159.46 3 0.372 16.99 108.72- -25.24 161.51 11 1 0.453 25.13 189.53 -17.98 135.61 2 0.443 24.03 181.23 -20.37 153.63 3 0.453 25.13 189.53 -19.76 149.03 12 1 0.461 26.05 178.10 -32.02 218.92 2 0.461 26.05 178.10 -31.75 217.07 3 0.421 21.72 148.50 -34.43 235.40 13 1 0.460 25.90 150.97 -35.59 207.45 2 0.469 27.03 157.56 -34.76 202.62 3 0.480 28.20 164.38 -38.04 221.74 14 1 0.432 22.86 157.96 -28.75 198.66 2 0.422 21.82 150.78 -24.33 168.12 3 0.432 22.86 157.96 -24.99 172.68 15 1 0.452 25.03 162.19 -26.31 170.49 2 0.462 26.16 169.52 -34.74 225.12 3 0.472 27.3.1 176.97 -32.19 208.59 X 22.78 148.747 -26.977 175.771 SD 3.862 23.949 4.467 25.114 SE 0.576 3.57 0.666 3.744 5 1 DEPTH JUMPS ("NO" MAT) #1 #2 #3 #5 SUBJ TRIAL AIR HEIGHT KINETIC LOWEST ECCENTRIC DROP # # . TIME JUMPED ENERGY DSPLCMNT ENERGY HEIGHT ( s e c ) (cm) ( J ) (cm) ( J ) (cm) 1 1 0.437 23.46 156.08 -20.99 315.95 26.50 2 0.437 23.46 156.08 -23.66 368.32 31.70 3 0.417 21.33 141.91 -17.99 276.70 23.60 2 1 0.488 29.21 192.96 -18.16 316.83 29.80 2 0.498 30.41 200.89 -17.60 323.70 31.40 3 0.482 28.54 188.54 -21.99 394.98 37.80 3 1 0.535 35.14 195.13 -14.42 258.01 32.00 2 0.566 39.24 218.11 -13.74 258.13 32.70 3 0.556 37.85 210.38 -18.07 304.42 36.70 4 1 0.435 23.18 133.80 -12.17 226.10 27.00 2 0.437 23.46 135.42 -11.84 249.01 31.30 3 0.436 23.27 134.32 -13.65 261.77 31.70 5 1 0.446 24.37 148.82 -10.98 255.15 30.80 2 0.446 24.37 148.82 -13.57 283.18 32.80 3 0.425 22.20 135.57 -15.07 298.45 33.80 6 1 0.460 25.90 184.92 -26.72 400.69 29.40 2 0.432 22.86 163.21 -23.84 343.00 24.20 3 0.482 28.48 203.34 -22.10 328.43 23.90 7 1 0.470 27.09 174.25 -12.77 301.47 34.10 2 0.470 27.09 174.25 -15.00 325.46 35.60 3 0.460 25.95 166.92 -14.56 253.16 24.80 8 1 0.492 29.68 200.44 -15.62 343.19 35.20 2 0.482 28.48 192.33 -18.53 385.04 38.50 3 0.492 29.68 200.44 -15.07 338.12 35.00 9 1 0.431 22.76 167.66 -20.56 403.42 34.20 2 0.461 26.05 191.89 -23.16 397.52 30.80 3 0.451 24.93 183.64 -19.21 400.10 35.10 10 1 0.442 23.98 153.45 -16.93 278.55 26.60 2 0.422 21.85 139.82 -16.39 282. 13 27.70 3 0.442 23.98 153.45 -19.28 295.51 26.90 11 1 0.492 29.74 224.30 -23.21 398.29 29.60 2 0.492 29.74 224.30 -22.93 375.06 26.80 3 0.472 27.36 206.35 -24.37 453.80 35.80 12 1 0.508 31 .70 216.72 -21.49 326.06 26.20 2 0.509 31 . 77 217.20 -24.95 359.97 27.70 3 0.509 31 .77 217.20 -18.86 298.50 24.80 13 1 0.492 29.74 173.36 -14.13 236.83 26.50 2 0.508 31 .64 184.43 -13.03 221.68 25.00 3 0.508 31.64 184.43 -12.91 211.65 23.40 14 1 0.490 29.50 203.85 -19.12 332.51 29.00 2 0.501 30.72 212.28 -13.06 330.02 34.70 3 0.501 30.72 212.28 -12.77 288.63 29.00 15 1 0.443 24.03 155.73 -17.06 284.21 26.80 2 0.493 29.80 193.12 -20.16 303.65 26.70 3 0.513 32.28 209.19 -22.24 311.95 25.90 X SD SE 27.787 181.817 -17.865 315.54 29.989 4.205 27.942 4.167 56.546 4.229 0.627 4.165 0.621 8.429 0.63 52 DEPTH JUMPS ("WITH" MAT) #1 #2 #3 #5 SUBJ TRIAL AIR HEIGHT KINETIC LOWEST ECCENTRIC DROP # # TIME JUMPED ENERGY DSPLCMNT ENERGY HEIGHT (sec) (cm) ( J ) (cm) ( J ) (cm) 1 1 0.363 16.15 107.45 -32.81 384.61 25.00 2 0.343 14.41 95.87 -23.43 339.50 27.60 3 0.373 17.06 113.50 -22.21 324.67 26.70 2 1 0.387 18.32 121.02 -24.00 407.59 37.70 2 0.366 16.45 108.67 -25.08 371.13 31.10 3 0.407 20.30 134.10 -29.67 397.48 30.50 3 1 0.465 26.53 147.45 -20.65 290.41 31.60 2 0.495 30.10 167.30 -21.66 333.81 38.40 3 0.485 28.88 160.52 -22.64 326.48 36.10 4 1 0.343 14.43 83.29 -21.29 260.84 23.90 2 0.375 17.23 99.45 -23.96 277.40 24.10 3 0.344 14.55 83.98 -19.61 253.45 24.30 5 1 0.356 15.55 94.96 -22.45 322.76 30.40 2 0.346 14.67 89.59 -22.54 337.35 32.70 3 0.407 20.30 123.97 -23.47 355.24 34.70 6 1 0.410 20.61 147.16 -27.29 356.93 22.70 2 0.410 20.61 147 .16 -35.77 432.47 24.80 3 0.400 19.62 140.09 -31.48 391.13 23.30 7 1 0.371 16.89 108.64 -30.02 383.48 29.60 2 0.391 18.76 120.66 -29.86 379.23 29.10 3 0.381 17.81 114.55 -20.03 390.28 25.10 8 1 0.369 16.72 112.91 -21.44 334.54 28.10 2 0.409 20.53 138.64 -26.84 394.65 31.60-3 0.399 • 19.54 131.95 -20.60. 358.92 32. 55 9 1 0.351 15.14. 111.54 -24.17 448.43 36. 70 2 0.332 13. 52 - 99.60 -24.84 462.21 37.90 3 0.342 14.35• 105.72 -28.34 470.31 35.50 10 1 0.339 14.12 90.35 -31.86 389.44 29.00 2 0.379 17.64 112.88 -29.34 389.32 31 .50 3 0.359 15.83 101.30 -32.77 360.71 23.60 11 1 0.418 21 .46 161.85 -27.68 423.71 28.50 2 0.350 15.05 113.51 -38.31 540.84 33.40 3 0.370 16.82 126.86 -38.10 538.50 33.30 12 1 0.453 25.13 171.81 -26.78 334.19 22.10 2 0.453 25.13 171.81 -29.09 329.48 19.10 3 0.459 25. 79 176.33 -27.19 371.18 27.10 13 1 0.400 19.66 114.60 -24.04 267.20 21 .80 2 0.410 20.65 120.37 -20.81 233.80 19.30 3 0.450 24.88 145.03 -21 .75 257.35 22.40 14 1 0.409 20.53 141.86 -30.10 382.12 25.20 2 0.399 19.54 135.02 -33.72 407.14 25.20 3 0.399 19.54 135.02 -31.48 399.95 26.40 15 1 0.441 23.84 154.48 -29.05 347.00 24.50 2 0.461 26.05 168.80 -29.36 315.97 19.40 3 0.431 22.76 147.49 -27.67 316.68 21.20 X 19.41 126.647 -26.783 361.996 28.106 SD 4.223 25.776 4.835 67.791 5.357 SE 0.63 3.842 0.721 10.106 0.799 APPENDIX E SUBJECT'S AVERAGED PER TRIAL DATA SUBJECTS1 AVERAGED TRIALS SQUAT JUMPS ("NO" MAT) #1 #2 SUBJ HEIGHT ECCENTRIC # JUMPED ENERGY (cm) ( J ) 1 20.820 138.517 2 27.433 181.227 3 33.557 186.520 4 23.003 132.780 5 25.827 157.717 6 22.937 163.763 7 23.340 150.133 8 26.647 179.950 9 19.867 146.367 10 26.023 166.527 11 26.483 199.737 12 27.873 190.557 13 26.450 154.183 14 24.673 170.497 15 28.177 182.597 I 25.541 166.738 SD 3.346 19.975 SE 0.864 5.157 ("WITH" MAT) n #2 ' SUBJ HEIGHT POSITIVE # JUMPED WORK (cm) ( J ) 1 14.847 98.780 2 21.027 138.903 3 27.470 152.680 4 18.273 105.480 5 21.653 132.023 6 17.930 128.013 7 17.510 112.633 8 22.243 150.217 9 18.917 139.367 10 16.457 105.310 11 17.510 132.060 12 21.540 147.260 13 22.973 133.913 14 18.650 128.880 15 18.860 122.223 X 19.724 128.516 SD 3.137 16.758 SE 0.81 4.327 SUBJECTS' AVERAGED TRIALS COUNTERMOVEMENT JUMPS ("NO" MAT) #1 #2 #3 #4 SUBJ HEIGHT KINETIC ECCENTRIC ENERGY # JUMPED ENERGY ENERGY CHANGE (cm) ( J ) ( J ) ( J ) 1 2 2.95 7 152.730 182.470 14.213 2 31.510 208.153 185.627 26.927 3 34.377 191.063 150.160 4.543 4 25.203 145.473 179.143 12.693 5 28.517 174.153 171.177 16.437 6 26.657 190.330 232.647 26. 567. 7 . 29.280 188.327 217.273 38.193 8 31.333 211.597 210.333 31.647 9 26.933 198.420 155.590 52.053 10 29.007 185.613 170.683 19.087 11 29.187 220.127 152.673 20.390 12 33.490 228.970 225.440 38.413 13 28.593 166.673 205.257 12.490 14 29.440 203.430 179.130 32.933 15 32.997 213.817 208.160 31 .2 20 X 29.299 191.925 188.384 25.187 SD 3.127 24.165 26.672 12.563 SE 0.807 6.24 6.887 3.244 ("WITH" MAT) #1' #2 #3 #4 SUBJ HEIGHT KINETIC ECCENTRIC ENERGY # JUMPED ENERGY ENERGY CHANGE (cm) . ( J ) ( J ) ( J ) 1 19.507 129.78 172.427 31 .000 2 27.077 178.867 188.033 39.963 3 30.210 167.910 151 .807 15.230 4 18.973 109.517 167.003 4.037 5 22.550 137.713 174.803 5.690 6 20.073- 143.320 175.437 15.307 7 19.187 123.407 143.007 10.773 8 21 .860 147.620 164.303 -2. 597 9 18.087 133.243 173.347 -6.123 10 19.077 122.073 164.687 16.763 11 24.763 186.763 146.090 54.703 12 24.607 168.233 223.797 20.973 13 27.043 157.637 210.603 23.723 14 22.513 155.567 179.820 26.687 15 26.167 169.560 201.400 7.337 X 22.78 148.747 175.771 20.231 SD 3.71 22.84 22.712 17.572 SE 0.958 5.897 5.864 4.537 56 SUBJECTS* AVERAGED TRIALS DEPTH JUMPS ("NO" MAT) #1 §2 #3 #4 ' #5 SUBJ HEIGHT KINETIC ECCENTRIC ENERGY DROP # JUMPED ENERGY ENERGY CHANGE HEIGHT (cm) ( J ) ( J ) ( J ) (cm) 1 22.750 151.357 320.323 12.840 27.267 2 29.387 194.130 345.170 12.903 33.000 3 37.410 207.937 273.520 21.417 33.000 4 23.303 134.513 245.627 1.733 • 30.000 5 23.647 144.403 278.927 -13.313 32.467 6 25.747 183.823 357.373 20.060 25.833 7 26.710 171.807 293.363 • 21.673 31.500 8 29.280 197.737 355.450 17.787 36.233 9 24.580 181.063 400.347 34.697 33.367 10 23.270 148.907 285.397 -17.62 27.067 11 28.947 218.317 409.050 18.58 30.733 12 31.747 217.040 328.177 . 26.483 26.233 13 31.007 180.740 223.387 26.557 24.967 14 . 30.313 209.470 317.053 38.973 30.900 15 28.703 186.013 299.937 3.417 26.467 X 27.787 181.817 315.54 15.079 29.989 SD 4.059 26.988 52.421 15.912 3.472 SE 1.048 6.968 '13.535 4.109 0.897 ' ("WITH " MAT) #1 #2 #3 #4 #5 SUBJ HEIGHT KINETIC ECCENTRIC ENERGY DROP # JUMPED ENERGY ENERGY CHANGE HEIGHT (cm) ( J ) ( J ) ( J ) (cm) 1 15.873 105.607 349.593 6.827 26.433 2 18.357 121.263 392.067 -17.640 33.100 3 28.503 158.423 316.900 5.743 35.367 4 15.403 88.907 263.897 -16.573 24.100 5 16.840 102.840 338.450 -29.183 32.600 6 20.280 144.803 393.510 16.790 23.600 7 17.820 114.617 350.997 1 .983 27.933 8 18.930 127.833 362.703 -22.383 30. 75 9 14.337 105.620 460.317 -33. 747 36.700 10 15.863 101.510 379.823 -3.800 28.033 11 17.777 134.073 501.017 2.013 31.733 12 25.350 173.317 344.950 26.057 22.766 13 21.730 126.667 252.783 -7.247 21.167 14 19.870 137.300 396.403 . 8.420 25.600 15 24.217 156.923 326.550 34.700 21.700 X 19.41 126.647 361.997 -1.869 28.106 SD 4.031 24.328 64.561 19.667 5.036 SE 1.041 6.281 16.67 5.078 1.300 

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