Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The effect of antecedent muscle tension levels on the performance of selected motor activities Shultz, Terry Donald 1977

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1977_A7_5 S24.pdf [ 3.17MB ]
Metadata
JSON: 831-1.0077115.json
JSON-LD: 831-1.0077115-ld.json
RDF/XML (Pretty): 831-1.0077115-rdf.xml
RDF/JSON: 831-1.0077115-rdf.json
Turtle: 831-1.0077115-turtle.txt
N-Triples: 831-1.0077115-rdf-ntriples.txt
Original Record: 831-1.0077115-source.json
Full Text
831-1.0077115-fulltext.txt
Citation
831-1.0077115.ris

Full Text

THE EFFECT OF ANTECEDENT MUSCLE TENSION LEVELS ON THE PERFORMANCE OF SELECTED MOTOR ACTIVITIES BY  TERRY DONALD SCHULTZ B.P.E., U n i v e r s i t y o f B r i t i s h Columbia, 1975  A t h e s i s submitted i n p a r t i a l  fulfillment  of t h e r e q u i r e m e n t s f o r t h e degree o f MASTER OF PHYSICAL EDUCATION in THE FACULTY OF GRADUATE STUDIES Department o f P h y s i c a l E d u c a t i o n and R e c r e a t i o n We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o t h e required standard  J u l y , 1977 (£) T e r r y Donald S c h u l t z , 1977  In p r e s e n t i n g t h i s t h e s i s an  in p a r t i a l  f u l f i l m e n t of  advanced degree at the U n i v e r s i t y of B r i t i s h  the L i b r a r y I further  s h a l l make i t f r e e l y  a v a i l a b l e for  agree t h a t p e r m i s s i o n f o r e x t e n s i v e  of  It  i s understood that  requirements  Columbia, reference  copying  f o r s c h o l a r l y purposes may be granted by the Head by h i s r e p r e s e n t a t i v e s .  the  of  copying  agree  and  this  of my  I  thesis  permission.  Department of  Physical Education  The U n i v e r s i t y o f B r i t i s h Columbia  2075 Wesbrook P l a c e Vancouver, Canada V6T 1WS  Date  Auguat 2, 1977  or  p u b l i c a t i o n  t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not b e a l l o w e d w i t h o u t m y  written  that  study.  Department or  for  ABSTRACT The  g e n e r a l purpose o f t h i s t h e s i s was t o determine  whether f u t u r e r e s e a r c h i n v o l v i n g EMG b i o f e e d b a c k c o m p e t i t i o n muscle r e l a x a t i o n t e c h n i q u e a t h l e t e s was w a r r a n t e d .  as a p r e -  f o r competitive  More s p e c i f i c a l l y , t h e g o a l s were  f i r s t t o determine i f t h e r e were i n c r e a s e s i n t h e muscle t e n s i o n l e v e l s o f competing a t h l e t e s p r i o r t o c o m p e t i t i v e  events  and then t o determine whether such i n c r e a s e s c o u l d a f f e c t t h e performance o f motor t a s k s . I n Experiment 1 t h e muscle t e n s i o n l e v e l s o f t h e r i g h t forearm f l e x o r and q u a d r i c e p muscle groups o f 10 c o l l e g i a t e w r e s t l e r s were monitored  p r i o r t o a c o m p e t i t i v e event  There was a s i g n i f i c a n t i n c r e a s e i n the l e v e l s o f muscle t e n s i o n o f t h e r i g h t forearm f l e x o r group.  I n Experiment 2  s u b j e c t s were asked t o reproduce these i n c r e a s e s i n muscle t e n s i o n w i t h t h e a i d o f EMG b i o f e e d b a c k ance of t h r e e motor s k i l l s .  p r i o r to the perform-  I t was d i s c o v e r e d t h a t such i n -  c r e a s e s i n muscle t e n s i o n d i s r u p t e d t h e performance o f b o t h the Hand-Steadiness and G r i p - S t r e n g t h T e s t s .  Thus, compet-  i t i v e a t h l e t e s do have e l e v a t e d p r e - c o m p e t i t i o n l e v e l s o f muscle t e n s i o n which may d i s r u p t some k i n d s o f motor p e r f o r m ance.  The p r e s e n t r e s u l t s , t h e r e f o r e , suggest t h a t f u t u r e r e  s e a r c h i n v o l v i n g EMG b i o f e e d b a c k r e l a x a t i o n technique  as a p r e - c o m p e t i t i o n muscle  f o r competitive a t h l e t e s i s warranted.  ACKNOWLEDGEMENTS The a u t h o r i s i n d e b t e d t o Dr. J . P . J P i n e l whose keen s u p e r v i s i o n and c r i t i c a l p e r c e p t i o n was a p p r e c i a t e d beyond words.  The a u t h o r a l s o w i s h e s t o thank Dr. R.  S c h u t z , M r s . S. B l e u l e r , D r . G. S i n c l a i r and Mr. R. Laycoe f o r t h e i r numerous c o n t r i b u t i o n s . A s p e c i a l thanks i s extended t o t h e many s u b j e c t s who v o l u n t e e r e d f o r t e s t i n g and  surrendered  countless layers of skin i n the process.  iii  TABLE OF CONTENTS Page ABSTRACT  . .  ACKNOWLEDGEMENTS  i i  i i i  LIST OF TABLES  vi  LIST OF FIGURES  v i i  Chapter 1.  INTRODUCTION TO THE PROBLEM  ........  Introduction Statement o f t h e Problem Hypotheses D e f i n i t i o n o f Terms Delimitations Limitations J u s t i f i c a t i o n o f t h e Study 2.  .  REVIEW OF THE LITERATURE S e c t i o n I : P h y s i o l o g y , Measurement, and Biofeedback. C o n t r o l , o f Muscle Tension . . . . . S e c t i o n I I : The Relevance o f t h e L i t e r a t u r e R e l a t i n g Muscle T e n s i o n and Performance  3.  METHODS AND PROCEDURES Introduction S e c t i o n I:' Methods and P r o c e d u r e s of Experiment 1 Subjects Apparatus Experimental Design Procedures S t a t i s t i c a l Analyses S e c t i o n I I : Methods and P r o c e d u r e s of Experiment 2 ... ... ... ... . ... ... . ... ... . Subjects iv  1 1 1 2 2 3 3 h 5  5 11 18 18 18 18 18 19 19 20 21 21  Experimental Design . . . . . Procedures Test 1: Hand-Steadiness T e s t . . . . . T e s t 2: C h o i c e Response-Time Test . . Test 3: G r i p - S t r e n g t h . Test .. ... ... .. .. ... S t a t i s t i c a l Analyses il-. RESULTS AND DISCUSSION  31  R e s u l t s o f Experiment 1 D i s c u s s i o n o f Experiment 1 R e s u l t s o f Experiment 2 T e s t 1: Hand-Steadiness Test T e s t 2: C h o i c e Response-Time T e s t . . T e s t 3: G r i p - S t r e n g t h T e s t ... ... ... ... ... ... D i s c u s s i o n o f Experiment 2 General D i s c u s s i o n Methodological Innovations Muscle T e n s i o n and S u b j e c t i v e T e n s i o n . . P h y s i o l o g i c a l Mechanisms S t r a t e g i e s o f A p p l i e d Research 5.  SUMMARY AND CONCLUSIONS  REFERENCES  22 23 26 27 29 30  . .  31 35 39 39 43 4-3 50 52 53 54 57 58 62 64  v  LIST OF TABLES Table 1.  Page E v a l u a t i o n o f Nine S t u d i e s o f t h e R e l a t i o n s h i p Between Muscle T e n s i o n and Performance w i t h Respect t o t h e A p p l i e d Goals of the Present Thesis . . .  13  2.  L a t i n Square D e s i g n o f Experiment 2 . . . .  22  3.  EMG A c t i v i t y o f t h e Forearm F l e x o r and Quadricep M u s c l e s Recorded D u r i n g the S i x T e s t i n g S e s s i o n s  34  ANOVA Table f o r t h e Forearm Muscle S i t e  36  4. 5. 6. 7. 8. 9. 10. 11.  Flexor  ANOVA Table f o r t h e Quadricep Muscle S i t e  36  Means and S t a n d a r d D e v i a t i o n s f o r t h e Two Measures o f Hand S t e a d i n e s s  42  P r o b a b i l i t y Values, f o r . the. HandS t e a d i n e s s Test  42  Means and S t a n d a r d D e v i a t i o n s f o r t h e Three Measures o f Speed o f Response . . . P r o b a b i l i t y V a l u e s f o r the. Choice Response-Time Test  46  Means and S t a n d a r d D e v i a t i o n s f o r t h e Two Measures o f G r i p - S t r e n g t h  49  P r o b a b i l i t y Values f o r the GripStrength Test  49  vi  46  LIST OF FIGURES Figure 1.  2.  Page Diagrammatic r e p r e s e n t a t i o n o f the t e m p o r a l sequence of e v e n t s d u r i n g each t e s t i n g session P r e - p r a c t i c e and p r e - c o m p e t i t i o n l e v e l s of muscle t e n s i o n i n the forearm, f l e x o r .. .. and q u a d r i c e p muscle groups  2>. R e l a t i o n between performance on t h e HandS t e a d i n e s s T e s t and a n t e c e d e n t l e v e l s of muscle t e n s i o n ..... V  4.  5.  25-  33  4l  R e l a t i o n between performance on t h e Choice Response-Time T e s t . a n d .antecedent l e v e l s . . o f muscle t e n s i o n  45  R e l a t i o n between performance on t h e G r i p S t r e n g t h T e s t and antecedent, l e v e l s of muscle t e n s i o n  48  vii  Chapter 1 INTRODUCTION TO THE PROBLEM Introduction The r e s e a r c h r e p o r t e d i n t h i s t h e s i s was based on the premise t h a t performance i n c o m p e t i t i v e s p o r t s may be r e l a t e d t o t h e l e v e l s o f muscle t e n s i o n i n t h e p e r i o d immed i a t e l y p r i o r t o competition.'  Although there i s general  s u p p o r t i n t h e e x p e r i m e n t a l l i t e r a t u r e f o r t h i s assumption of a r e l a t i o n between l e v e l s o f muscle t e n s i o n and performance, o n l y a few o f t h e e x i s t i n g s t u d i e s a r e m e t h o d o l o g i c a l l y adequate and none i s d i r e c t l y r e l a t e d t o t h e s p e c i f i c a p p l i e d g o a l s o f t h i s t h e s i s (see C h a p t e r 2 ) . The r e c e n t development  of biofeedback procedures f o r  t r a i n i n g s u b j e c t s t o c o n t r o l t h e i r l e v e l s o f muscle t e n s i o n r a i s e s t h e p o s s i b i l i t y t h a t c o m p e t i t i v e a t h l e t e s c o u l d enhance t h e i r performance by l e a r n i n g t o c o n t r o l t h e i r  levels  of muscle t e n s i o n i n t h e p e r i o d p r i o r t o c o m p e t i t i o n . Statement o f t h e Problem The g e n e r a l purpose o f t h i s t h e s i s was t o t e s t t h e f e a s i b i l i t y o f u s i n g EMG b i o f e e d b a c k t e c h n i q u e s t o improve a t h l e t i c performance.  Two e x p e r i m e n t s were conducted t o  t e s t the p o s s i b i l i t y of using t h i s technique.  The purpose  of t h e f i r s t experiment was t o t e s t t h e h y p o t h e s i s 1  that  2 muscle t e n s i o n l e v e l s o f c o m p e t i t i v e a t h l e t e s are markedlyelevated p r i o r to competition.  The purpose of the second  experiment was t o determine whether the i n c r e a s e s i n muscle t e n s i o n of the magnitude  observed i n a t h l e t e s p r i o r t o comp-  e t i t i o n were s u f f i c i e n t t o d i s r u p t the performance of t h r e e s e l e c t e d motor t a s k s . Hypotheses (1)  C o m p e t i t i v e a t h l e t e s have e l e v a t e d muscle  tension  l e v e l s p r i o r to a competitive event. (2)  Induced muscle t e n s i o n l e v e l s of the magnitude  r e c o r d e d i n Experiment 1 d i s r u p t the performance o f motor activites. D e f i n i t i o n o f Terms 1.  E l e c t r o m y o g r a p h (EMG).  When a muscle f i b e r i s  a c t i v a t e d by a nervous impulse a r r i v i n g a t the neuromuscular j u n c t i o n , a p o s i t i v e 5-to-10 msec, 50-to-100 mV change i n membrane p o t e n t i a l precedes c o n t r a c t i o n .  This a l l - o r - n o t h i n g  e l e c t r i c a l change a c r o s s the membrane of a s i n g l e muscle f i b e r i s c a l l e d a muscle a c t i o n p o t e n t i a l .  The sumr,over time  o f numerous a c t i o n p o t e n t i a l s r e c o r d e d by p l a c i n g g r o s s s u r f a c e e l e c t r o d e s over, o r i n s e r t i n g needle e l e c t r o d e s i n t o , a muscle i s c a l l e d an e l e c t r o m y o g r a p h . 2.  Root-Mean-Square (RMS).  RMS  i s a sophisticated  and s e n s i t i v e method of q u a n t i f y i n g the EMG.  T h i s form of  3  a n a l y s i s p r o v i d e s a measure of the t o t a l a r e a under the c u r v e , or waveform and  i s thus s e n s i t i v e t o the d u r a t i o n  i n d i v i d u a l waves as w e l l as t h e i r magnitude and 3.  EMG  Biofeedback.  of  frequency.  Biofeedback involves  providing  s u b j e c t s w i t h immediate and a c c u r a t e i n f o r m a t i o n  about  changes i n t h e i r p h y s i o l o g i c a l s t a t e , thus p r o v i d i n g them w i t h a b a s i s f o r a c c u r a t e l y c o n t r o l l i n g the f u n c t i o n s measured.  U s u a l l y the feedback i s p r o v i d e d  being  i n the form of  a u d i t o r y or v i s u a l s i g n a l s . Delimitations The  d e l i m i t a t i o n s are: 1.  Experiment 1 i s d e l i m i t e d t o  competitive  collegiate wrestlers. 2.  Experiment 2 i s d e l i m i t e d t o male under-  graduate p h y s i c a l e d u c a t i o n 3.  The  r e s u l t s of Experiment 2 are  t o the t h r e e motor t a s k s 4.  The  students. delimited  selected.  r e s u l t s of Experiment 2 are  delimited  t o the s p e c i f i c muscle t e n s i o n ranges s e l e c t e d (i.e.  0.5  uV t o  10.5  uV).  Limitations The  l i m i t a t i o n s are: 1.  The  EMG  a c t i v i t y of the w r e s t l e r s  p a t i n g i n Experiment 1 was  partici-  monitored approximately  1 hour b e f o r e the c o m p e t i t i v e w r e s t l i n g event. 2.  I n Experiment 2, muscle t e n s i o n was i n -  duced i n the r i g h t forearm of the s u b j e c t s f o r p e r i o d s r a n g i n g from 10 t o 40  minutes.  J u s t i f i c a t i o n of the S t u d y I f p o s i t i v e r e s u l t s are i n d i c a t e d , the r e s u l t s of the p r e s e n t s t u d i e s w i l l p r o v i d e a b a s i s f o r f u t u r e work i n v o l v i n g EMG  biofeedback r e l a x a t i o n techniques.  s e a r c h e x t e n d i n g from t h i s t h e s i s may  Thus, r e -  eventually provide a  method f o r i m p r o v i n g a t h l e t i c performance by  controlling  a t h l e t e s ' p r e - c o m p e t i t i o n l e v e l s o f muscle t e n s i o n .  Chapter 2 REVIEW OF  THE  LITERATURE  Introduction This chapter i s divided  i n t o two  sections.  The  purpose of the f i r s t i s t o p r o v i d e the r e a d e r w i t h an s t a n d i n g of the p h y s i o l o g y of muscle t e n s i o n , t e n s i o n has can be studies  t y p i c a l l y been measured, and  c o n t r o l l e d by b i o f e e d b a c k .  how  I n the  how  muscle  muscle  second  reviewed and  Biofeedback  n o r m a l r e s t i n g membrane p o t e n t i a l  t h a t i s , i n i t s r e s t i n g s t a t e the  ous  outside.  to  Control  of i n d i v i d u a l s k e l e t a l muscle f i b e r s i s about minus 85  t o the  per-  i s discussed.  S e c t i o n I : P h y s i o l o g y , Measurement, and of Muscle T e n s i o n The  and  the r e l e v a n c e of these s t u d i e s  the p r e s e n t i n v e s t i g a t i o n s  ' Physiology.  tension  section,  of the r e l a t i o n s h i p between muscle t e n s i o n  formance a r e  under-  i n s i d e i s 85 mV  mV;  negative  When a muscle f i b e r i s a c t i v a t e d by a n e r v -  impulse a r r i v i n g a t the n e u r o m u s c u l a r j u n c t i o n , a pos-  i t i v e 5 - t o - 1 0 msec, 5 0 - t o - 1 0 0 mV precedes c o n t r a c t i o n  change i n membrane p o t e n t i a l  (Guyton, 1971)•  This  all-or-nothing  e l e c t r i c a l change a c r o s s the membrane of a s i n g l e muscle f i b e r i s c a l l e d a muscle a c t i o n p o t e n t i a l ( d e V r i e s ,  1976).  6  The a c t i v i t y o f i n d i v i d u a l muscle f i b e r s i s r a r e l y recorded  i n - b e h a v i o u r a l experiments.  I n s t e a d summated a c -  t i v i t y o f many muscle f i b e r s i s r e c o r d e d  through  gross  e l e c t r o d e s which a r e , i n most c a s e s , f i x e d t o the s u r f a c e of t h e s k i n (Basmajian, (EMG)  1974).  The raw e l e c t r o m y o g r a p h  o b t a i n e d by p l a c i n g s u r f a c e e l e c t r o d e s over a whole  muscle i s t y p i c a l l y a composite o f the muscle a c t i o n pot e n t i a l s o f f i b e r s b e l o n g i n g t o many motor u n i t s (Thompson, L i n d s l e y , and Eason, 1 9 6 6 ) .  Increased n e u r a l input i n t o a  muscle can r e s u l t i n i n c r e a s e d a c t i v a t i o n o f the p r e v i o u s l y a c t i v e f i b e r s , an i n c r e a s e i n t h e number o f f i b e r s a c t i v a t e d , or a combination  of both.  being  As n e u r a l i n p u t t o a  muscle i n c r e a s e s t h r e e b a s i c changes i n t h e raw EMG s i g n a l can occur:  t h e r e can be i n c r e a s e s i n t h e p o t e n t i a l d i f f e r e n c e  between t h e p o s i t i v e and n e g a t i v e waves, i n c r e a s e s i n the frequency  o f t h e waves, and i n c r e a s e s i n t h e average d u r a t i o n  of i n d i v i d u a l waves (Guyton, 1971)• I t s h o u l d be emphasized t h a t the EMG i s n o t a d i r e c t measure o f the degree o f m u s c u l a r c o n t r a c t i o n .  However,  t h e r e i s , under normal c o n d i t i o n s , an e x t r e m e l y  correla-  t i o n between t h e e l e c t r i c d i s c h a r g e  high  o f a motor u n i t and the  m u s c u l a r c o n t r a c t i o n t h a t f o l l o w s (Thompson e t a l . , Measurement o f muscle t e n s i o n .  1966).  Several different  methods o f e s t i m a t i n g muscle t e n s i o n l e v e l s have been developed.  P r i o r t o t h e development o f t h e electromyogram,  7  i n v e s t i g a t o r s had t h e i r s u b j e c t s p u l l w e i g h t s o f v a r y i n g l o a d s i n an attempt t o induce muscle t e n s i o n .  They i m p l i c -  i t l y assumed t h a t the amount o f weight p u l l e d would be p r o p o r t i o n a l t o the r e s u l t i n g muscle t e n s i o n l e v e l s and t h a t the l e v e l s o f induced t e n s i o n would be the same f o r d i f f e r e n t i n d i v i d u a l s i f t h e y p u l l e d the same weight l o a d .  Obviously  such i n d i r e c t methods a r e i n a d e q u a t e , and i t i s u n f o r t u n a t e t h a t these methods were employed i n most o f the e a r l y s t u d i e s of the r e l a t i o n s h i p between muscle t e n s i o n and performance (1930-1960).  The EMG t e c h n i q u e s f o r d i r e c t l y measuring t h e e l e c t r i c a l a c t i v i t y o f muscles were w i d e l y adopted around Initially  i960.  i n v e s t i g a t o r s photographed the d i s p l a y o f raw  EMG s i g n a l s from an o s c i l l o s c o p e s c r e e n and e s t i m a t e d average' a m p l i t u d e o f t h e waves.  Considering  the  'the  complexity  of t h e EMG waveform, i t i s n o t s u r p r i s i n g t h a t such s u b j e c t i v e methods were e v e n t u a l l y abandoned. More o b j e c t i v e methods o f q u a n t i f y i n g the raw EMG s i g n a l a r e now used i n most r e s e a r c h . s i g n a l i s a u t o m a t i c a l l y analyzed i c a l l y displayed.  I n each case t h e raw  and the r e s u l t s a r e graph-  However, t h e r e a r e t h r e e b a s i c a l l y d i f -  f e r e n t methods o f a n a l y z i n g the EMG s i g n a l (James & H o r t o n , 1976).  The f i r s t and most simple method i s s e n s i t i v e t o  o n l y t h e average p o t e n t i a l d i f f e r e n c e between the p o s i t i v e and  the negative  peaks o f t h e raw EMG s i g n a l .  The obvious  problem w i t h t h i s 'peak-to-peak* method i s t h a t i t i s n o t  8 s e n s i t i v e t o i n c r e a s e s i n the number of waves, n o r i s i t s e n s i t i v e t o i n c r e a s e s i n the d u r a t i o n o f t h e i n d i v i d u a l waves c o m p r i s i n g  the EMG s i g n a l .  The second method of quan-  t i f y i n g EMG s i g n a l s i s s e n s i t i v e t o b o t h the h e i g h t and the f r e q u e n c y o f the EMG waves.  S i n c e the c i r c u i t r y r e q u i r e d  for t h i s 'integral-average' analysis i s b a s i c a l l y quite s i m p l e , i t has been used e x t e n s i v e l y .  However, t h i s method  of a n a l y s i s i s n o t s e n s i t i v e t o changes i n the d u r a t i o n o f i n d i v i d u a l waves. The t h i r d and most s e n s i t i v e measure o f muscle t e n s i o n i s the root-mean-square (RMS) method.  T h i s form o f  a n a l y s i s p r o v i d e s a measure o f t h e t o t a l a r e a under the EMG c u r v e , and i s thus s e n s i t i v e t o the d u r a t i o n o f i n d i v i d u a l waves as w e l l as t h e i r magnitude and f r e q u e n c y .  Thus, t h i s  method o f a n a l y z i n g the EMG s i g n a l i s more s e n s i t i v e t o changes i n muscle t e n s i o n than a r e the o t h e r two (James & Horton, 19?6).  T h i s RMS method o f EMG q u a n t i f i c a t i o n was  employed i n b o t h s t u d i e s c o m p r i s i n g  the p r e s e n t thesis,-.  B i o f e e d b a c k c o n t r o l of muscle t e n s i o n .  The c o n t r o l  of muscle t e n s i o n by b i o f e e d b a c k i s r e l a t e d t o the p r e s e n t d i s c u s s i o n i n two ways.  F i r s t , b i o f e e d b a c k was used i n Ex-  p e r i m e n t 2 as a method o f s t u d y i n g the r e l a t i o n s h i p between muscle t e n s i o n and performance; p r i o r t o the t e s t o f p e r f o r mance s u b j e c t s l o o k e d a t a d i s p l a y o f the muscle t e n s i o n i n t h e i r r i g h t f o r e a r m f l e x o r group and a d j u s t e d the t e n s i o n t o produce t h e d e s i r e d RMS r e a d i n g s .  Second, as mentioned i n  9  the p r e v i o u s c h a p t e r ,  t h e g e n e r a l purpose o f t h i s t h e s i s  was t o t e s t t h e f e a s i b i l i t y o f u s i n g b i o f e e d b a c k  techniques  t o improve a t h l e t i c performance. Biofeedback  simply involves providing subjects with  immediate and a c c u r a t e i n f o r m a t i o n about changes i n t h e i r p h y s i o l o g i c a l s t a t e , thus p r o v i d i n g them w i t h a b a s i s f o r a c c u r a t e l y c o n t r o l l i n g t h e f u n c t i o n s b e i n g measured.  Usually  the feedback i s p r o v i d e d i n t h e form o f a u d i t o r y o r v i s u a l signals.  F o r example, B u d z y n s k i ,  Stoyva,  and A l d e r (197.0)  a t t a c h e d s u r f a c e e l e c t r o d e s t o t h e f r o n t a l i s muscle o f f i v e hypertensive  i n d i v i d u a l s and 'fed-them-back' a tone w i t h a  f r e q u e n c y p r o p o r t i o n a l t o t h e average peak-to-peak EMG a c t i v i t y of t h e i r f r o n t a l i s muscles.  The s u b j e c t s soon l e a r n e d  t o lower t h e t e n s i o n l e v e l s o f t h e f r o n t a l i s muscles i n t h e l a b o r a t o r y s i t u a t i o n , and t h i s r e d u c t i o n r e s u l t e d i n a d i m i n u t i o n o f t h e a s s o c i a t e d headache a c t i v i t y . Mosely, and McGowan  (1975)  and B u d z y n s k i  Haynes,  and S t o y v a  showed t h a t s u b j e c t s p r a c t i c i n g b i o f e e d b a c k  (1969)  could l e a r n to  reduce muscle t e n s i o n l e v e l s b e t t e r and f a s t e r t h a n c o n t r o l groups t r y i n g t o r e l a x on t h e i r own. and E l l s w o r t h ( 1 9 6 6 ) , B u d z y n s k i  Hardyck, P e t r i n o v i c h ,  and S t o y v a ( 1 9 7 0 , and Bud-  z y n s k i e t a l . (1971) found t h a t b o t h the r e d u c t i o n o f f r o n t a l i s EMG a c t i v i t y and t h e d i m i n u t i o n o f headaches were e n d u r i n g consequences o f b i o f e e d b a c k  which c a r r i e d  over t o t h e s u b j e c t s ' l i v e s o u t s i d e t h e l a b o r a t o r y e n v i r o n ment.  10  A major impetus f o r b i o f e e d b a c k r e s e a r c h was p r o v i d e d b y t h e c l a i m o f M i l l e r (1969) and D i C a r a (1970) t h a t c u r a r i z e d a n i m a l s c o u l d c o n t r o l a v a r i e t y o f autonomic f u n c tions.  P r e v i o u s l y i t had been assumed t h a t such autonomic  f u n c t i o n s c o u l d n o t be brought under v o l u n t a r y c o n t r o l , and as a r e s u l t t h i s work s t i m u l a t e d i n t e r e s t i n the e n t i r e a r e a of b i o f e e d b a c k . A l t h o u g h some o f M i l l e r and D i C a r a ' s autonomic  condi-  t i o n i n g e x p e r i m e n t s have t u r n e d out t o be c o n t r o v e r s i a l ( c f . B l a n c h a r d & Young, 1974), EMG b i o f e e d b a c k has been r e p e a t e d l y shown t o improve a v a r i e t y o f b e h a v i o u r a l problems. F o r example, M a r i n a c c i and Horande ( i 9 6 0 ) and Andrews (1964) t r a i n e d p a t e i n t s t o move p a r a l y z e d m u s c l e s .  The p a r a l y s i s  had been caused b y e i t h e r a s t r o k e o r motor nerve  injury  and had i n each case remained u n r e s p o n s i v e t o c o n v e n t i o n a l methods o f neuromuscular r e h a b i l i t a t i o n f o r over a y e a r . . I n b o t h s t u d i e s n e e d l e e l e c t r o d e s were i n s e r t e d i n the p a r a l y z e d muscles and t h e p a t i e n t s were p r o v i d e d w i t h feedback i n t h e form o f a tone w i t h a volume p r o p o r t i o n a l t o the peak-to-peak EMG a c t i v i t y .  The s u b j e c t s were t r a i n e d t o  i n c r e a s e t h e sound, t h e r e b y g e n e r a t i n g movement, and w i t h i n one t r a i n i n g s e s s i o n a l l s u b j e c t s i n b o t h s t u d i e s developed s t r o n g , v o l u n t a r y , w e l l modulated responses i n the p r e v i o u s l y p a r a l y z e d muscles. I n a n o t h e r example o f t h e e f f e c t i v e c l i n i c a l app l i c a t i o n o f EMG b i o f e e d b a c k , Hardyck, P e t r i n o v i c h , and  Ellsworth  (1966)  completely abolished s u b v o c a l i z a t i o n (the  movement o f t h e l a r y n g e a l muscles w h i l e r e a d i n g s i l e n t l y ) , which s e r i o u s l y reduces r e a d i n g speed ( B l a n c h a r d & Young, 1974).  A l t h o u g h t h e s u b v o c a l i z a t i o n d i s p l a y e d by t h e 17  c h i l d r e n i n t h e Hardyck, P e t r i n o v i c h , and E l l s w o r t h s t u d y had p r o v e d r e f r a c t o r y t o o t h e r t y p e s o f i n t e r v a t i o n , b i o feedback was c o m p l e t e l y s u c c e s s f u l i n a l l 17 c a s e s .  The  feedback was i n t h e form o f an a u d i t o r y tone w i t h a f r e quency p r o p o r t i o n a l t o t h e peak-to-peak EMG a c t i v i t y o f t h e l a r y n g e a l muscles.  Moreover, none o f t h e s u b j e c t s "sub-  v o c a l i z e d " d u r i n g f o l l o w - u p t e s t s conducted 1 o r 3 months later. Thus, b i o f e e d b a c k has p r o v e n e f f e c t i v e i n h e l p i n g s u b j e c t s g a i n c o n t r o l over t h e i r s p e c i f i c m u s c u l a r s t a t e w i t h r e s u l t i n g b e n e f i c i a l c l i n i c a l effects i n several instances. A l t h o u g h o t h e r t e c h n i q u e s such as p r o g r e s s i v e (Jacobson, 1 9 3 8 ) ,  relaxation  s y s t e m a t i c d e s e n s i t i z a t i o n (Wolpe,  1958),  and a u t o g e n i c t r a i n i n g ( L u t h e , 1968) have been used t o p r o duce a l t e r a t i o n s i n muscle t e n s i o n l e v e l s , b i o f e e d b a c k ' s e f f i c a c y c o u p l e d w i t h i t s i n h e r e n t p r e c i s i o n and o b j e c t i v i t y make i t s u p e r i o r as b o t h a r e s e a r c h and c l i n i c a l Section I I : The Relevance o f t h e L i t e r a t u r e Muscle T e n s i o n and Performance  tool.  Relating  A l t h o u g h t h e r e s u l t s o f most o f t h e e x i s t i n g  studies  s u p p o r t t h e g e n e r a l a s s u m p t i o n t h a t muscle t e n s i o n can have an e f f e c t on performance, a thorough a n a l y s i s o f t h e ex-  12  p e r i m e n t a l l i t e r a t u r e on t h e r e l a t i o n between muscle t e n s i o n and performance d i d n o t r e v e a l a s i n g l e s t u d y d i r e c t l y r e l e v a n t to the a p p l i e d goals of the present t h e s i s .  There  a r e two main f e a t u r e s o f t h e l i t e r a t u r e which p r e c l u d e any p o s s i b i l i t y of a p p l y i n g i t t o the goals of the present  thesis.  F i r s t , t h e methodology o f p r e v i o u s s t u d i e s i n t h i s a r e a has been g e n e r a l l y poor; and second,  even when t h e d e s i g n and  methods o f t h e s t u d i e s were adequate, t h e i r r e s u l t s had l i t t l e d i r e c t relevance t o the s p e c i f i c a p p l i e d g o a l of improving the performance o f c o m p e t i t i v e a t h l e t e s .  To i l l u s t r a t e  these two problems t h e n i n e s t u d i e s judged t o be t h e most r e l e v a n t t o t h e purpose o f t h i s t h e s i s a r e reviewed i n t h i s chapter.  These s t u d i e s a r e l i s t e d and e v a l u a t e d i n Table 1  i n r e l a t i o n t o the present  objectives.  The most obvious m e t h o d o l o g i c a l inadequacy  charac-  t e r i s t i c o f these s t u d i e s i s t h e i r f a i l u r e t o measure muscle t e n s i o n l e v e l s a c c u r a t e l y . I n s i x o f t h e n i n e s t u d i e s , subj e c t s p u l l e d w e i g h t s o r squeezed dynamometers and changes i n muscle t e n s i o n were assumed, w h i l e t h e measurement t e c h n i q u e s used i n t h e o t h e r t h r e e s t u d i e s l e f t much t o be d e s i r e d . F o r example, Freeman (1933) used a crude method o f tendon deformat i o n and photography i n an attempt t o q u a n t i f y muscle t e n s i o n levels.  A l e v e r , s e r v i n g t o depress the p a t e l l a r  tendon,  was connected w i t h an o p t i c a l system which m a g n i f i e d changes i n t h e tendon d e f o r m a t i o n .  I t was assumed t h a t t h e degree  of d e f o r m a t i o n p r o v i d e d an a c c u r a t e e s t i m a t e o f t h e degree  Table 1 E v a l u a t i o n of Nine S t u d i e s o f the R e l a t i o n s h i p Between Muscle Tension and Performance w i t h Respect t o the A p p l i e d . Goals o f the P r e s e n t T h e s i s Investigator  Were measures of EMG adequate (•) or inadequate (x)  Was muscle t e n s i o n induced before (*/) or d u r i n g (x) t a s k s  Were a p p r o p r i a t e or i n a p p r o p r i a t e muscle t e n s i o n l e v e l s induced  (•) (x)  Were the s u b j e c t s a t h l e t e s (•") or n o n a t h l e t e s (x)  Were the t a s k s d i r e c t l y .(•) r e l a t e d to s p o r t s or not (x)  Russell (1932) ball Freeman (1933) Stauffaeher (1937)  tossing  findings  The degree o f a c c u r a c y and the degree o f t e n s i o n a r e inversely related  reaction  time  I n c r e a s e d t e n s i o n due to a n t i c i p a t i o n of t a s k d i f f i c u l t y i n c r e a s e s e f f i c i e n c y of r e a c t i o n  nonsense  syllables  B e s t performances n o t e d a t h a l f i n d i v i d u a l s maximum contraction  Freeman (1938) finger Courts (19^2) Bell (1959)  Major  oscillations  V  Number o f o s c i l l a t i o n s with increased tension  one-  increases  pursuit  rotor  B e s t performances n o t e d a t o n e - e i g h t h and o n e - h a l f maximal c o n t r a c t i o n  pursuit  rotor  N e i t h e r t e n s i o n or m o t i v a t i o n a l t e r t e d performance  Pinneo (1961) auditory tracking  L e v e l o f muscle t e n s i o n and a c t i v a . t i o n c l o s e l y related  reaction  R e a c t i o n and movement times fastest i n tension conditions  Smith (1964) time  Parker (1973) time  estimation  Most a c c u r a t e performances o c c u r r e d a t the 50# i n d u c e d muscle t e n s i o n l e v e l  14  of muscle t e n s i o n . c o r d EMG  Although  Smith (1964) attempted to r e -  a c t i v i t y , the e l e c t r o d e s were so p o o r l y  attached  t h a t t h e y f e l l from the s k i n s u r f a c e of e v e r y s u b j e c t a f t e r o n l y a few t r i a l s .  I n the r e m a i n i n g  t r i a l s he f e l t  the  muscles i n an attempt t o e s t i m a t e the amount of muscle t e n sion.  P i n n e o (1961) q u a n t i f i e d the EMG  signals using  the  o b j e c t i v e , b u t r e l a t i v e l y i n s e n s i t i v e , peak-to-peak method. Another methodological f a c t t h a t the a u t h o r s  inadequacy stems from the  of the n i n e a r t i c l e s r e q u i r e d s u b j e c t s  t o p e r f o r m one t a s k t o induce muscle t e n s i o n w h i l e a t the same time a s s e s s i n g performance on a n o t h e r .  For example,  i n s e v e r a l s t u d i e s s u b j e c t s p u l l e d w e i g h t s o r squeezed dynamometers w i t h one arm w h i l e p e r f o r m i n g w i t h the o t h e r ( B e l l , 1 9 5 9 ;  on a p u r s u i t r o t o r Pinneo, 1 9 6 1 ) .  Courts, 1942;  The problem i s t h a t a t a s k , no m a t t e r how  simple,  inevitably  i n t e r f e r e s w i t h the performance of a n o t h e r t a s k b e i n g formed a t the same time (Broadbent & Gregory, I 9 6 3  &  per1965)•  Thus, d i s r u p t i o n of performance n o t e d i n these s t u d i e s of muscle t e n s i o n may other a c t i v i t y  have been caused a t l e a s t i n p a r t by  ( i . e . squeezing  the  or p u l l i n g ) r a t h e r t h a n by  the i n c r e a s e s i n muscle t e n s i o n p e r se.  Unfortunately,  the  a p p r o p r i a t e c o n t r o l s were n e v e r i n c l u d e d i n these s t u d i e s . t o d i f f e r e n t i a t e between these two  possibilities.  Even i f these s t u d i e s were w i t h o u t  s e r i o u s method-  o l o g i c a l problems, i t would s t i l l be d i f f i c u l t t o a p p l y r e s u l t s t o the p r a c t i c a l g o a l s of the p r e s e n t t h e s i s .  their Be-  15  cause none had a p p l i e d g o a l s , t h e i r methods do n o t appear t o have been s e l e c t e d w i t h p r a c t i c a l a p p l i c a t i o n s i n mind.  For  example, r e s t i n g muscle t e n s i o n l e v e l s r a r e l y exceed 10 uV RMS i n the p e r i o d p r i o r t o competition  ( c f . Experiment 1 ) , y e t  i n t h e n i n e s t u d i e s muscle t e n s i o n was induced by e x t e r n a l l o a d s r e q u i r i n g muscle t e n s i o n l e v e l s r a n g i n g from one e i g h t h t o maximal c o n t r a c t i o n e q u i v a l e n t t o RMS EMG l e v e l s of 125 t o 1000 uV.  These v a l u e s a r e o b v i o u s l y w e l l out o f  the normal r e s t i n g range.  I n a d d i t i o n , i n many o f the p r e -  v i o u s s t u d i e s o f muscle t e n s i o n and performance, t h e p e r f o r mance s t u d i e d had l i t t l e d i r e c t r e l a t i o n s h i p t o a c t u a l a t h l e t i c events.  F o r example, i n two o f t h e n i n e s t u d i e s c i t e d , t h e  e f f e c t o f v a r y i n g muscle t e n s i o n on f i n g e r o s c i l l a t i o n s and time e s t i m a t i o n was a s s e s s e d ;  whereas t h e l e a r n i n g o f non-  sense s y l l a b l e s was i n v e s t i g a t e d i n a n o t h e r .  Moreover, a s  mentioned p r e v i o u s l y , i n a l l o f t h e s t u d i e s a t t e m p t s were made t o a s s e s s t h e e f f e c t s o f v a r y i n g l e v e l s o f muscle t e n s i o n d u r i n g t h e performance o f t h e b e h a v i o u r a l t e s t s .  However,  i n most c a s e s i t would n o t be f e a s i b l e t o a p p l y such r e s u l t s to a c t u a l competitive  events, n o r would i t be p o s s i b l e , f o r  e t h i c a l and t e c h n i c a l r e a s o n s , t o r e c o r d EMG a c t i v i t y important  athletic  during  competitions.  I n view o f t h e b a s i c n a t u r e  of the goals of the pre-  sent t h e s i s , i t i s i n t e r e s t i n g t o c o n s i d e r why t h e l i t e r a t u r e c o n t a i n s no d i r e c t l y r e l e v a n t d a t a .  Many o f t h e m e t h o d o l o g i c a l  16  i n a d e q u a c i e s are c l e a r l y r e l a t e d t o t h e f a c t t h a t most o f the work was done b e f o r e t h e development o f a c c u r a t e EMG techniques.  F o r example, t h e electromyogram  was o n l y r a r e l y  employed i n r e s e a r c h b e f o r e i960 (Basmajian, 1974) and RMS t e c h n i q u e s were n o t commonly used u n t i l 1975-  Other method-  o l o g i c a l problems seem t o be r e l a t e d t o g e n e r a l l a c k o f experimental s o p h i s t i c a t i o n generally c h a r a c t e r i s t i c of early r e s e a r c h i n the b e h a v i o u r a l s c i e n c e s .  F o r example, b o t h  C o u r t s (1942) and R u s s e l l (1932) r e p o r t e d group means w i t h o u t p r o v i d i n g the r e a d e r w i t h an e s t i m a t e o f t h e s i g n i f i c a n c e o f the d i f f e r e n c e s between them, and they d i d n o t even p r o v i d e i n f o r m a t i o n c o n c e r n i n g the v a r i a b i l i t y o f t h e i r d a t a  which  would a l l o w r e a d e r s t o e s t i m a t e t h e s i g n i f i c a n c e l e v e l s f o r themselves. The l a c k o f a p p l i c a b i l i t y o f the r e s u l t s t o a p p l i e d problems seems t o stem from a c o m b i n a t i o n o f two f a c t o r s . F i r s t , most o f the work was t h e o r e t i c a l l y o r i e n t e d and second, the t h e o r i e s which g u i d e d t h e r e s e a r c h were vague and based on l i t t l e e m p i r i c a l e v i d e n c e .  F o r example, i m p l i c i t i n  most e a r l y t h e o r i e s was t h e assumption t e n s i o n were c o n s i s t e n t throughout  t h a t s t a t e s o f muscle  the body.  c e n t evidence has proven t h i s assumption Alexander  However, r e -  t o be i n c o r r e c t .  (1975) r e c o r d e d the EMG a c t i v i t y o f the f r o n t a l i s ,  the forearm, and the c a l f muscles d u r i n g EMG b i o f e e d b a c k sessions. was  A l t h o u g h the EMG a c t i v i t y o f t h e f r o n t a l i s muscle  s i g n i f i c a n t l y reduced, the EMG r e d u c t i o n was n o t gener-  a l i z e d t o the other s i t e s .  E a r l i e r t h e o r e t i c a l formulations  of t h e r e l a t i o n between muscle t e n s i o n and performance a l s o f a i l e d t o d i s t i n g u i s h between t h e e f f e c t s of muscle t e n s i o n on v a r i o u s k i n d s o f b e h a v i o u r .  I t seems t o have been im-  p l i c i t l y assumed t h a t changes i n muscle t e n s i o n would i n f l u e n c e a l l b e h a v i o u r s i n the same way.  Apparently,  as a  r e s u l t of the shortcomings of e a r l y t h e o r e t i c a l formulations of t h e r e l a t i o n between muscle t e n s i o n and performance, e a r l y i n v e s t i g a t o r s seem t o have g i v e n l i t t l e thought t o the e x a c t muscles t h e y s t u d i e d or t o t h e ' e x a c t  t a s k s used t o a s s e s s  the consequences of changes i n muscle t e n s i o n .  The r e c o r d i n g  s i t e s and the b e h a v i o u r a l t a s k s seem t o have been s e l e c t e d f o r t e c h n i c a l r a t h e r than l o g i c a l reasons.  Chapter 3 METHODS AND PROCEDURES Introduction T h i s c h a p t e r i s d i v i d e d i n t o two s e c t i o n s .  The  purpose o f t h e f i r s t i s t o p r o v i d e t h e r e a d e r w i t h an understanding  o f t h e methods and p r o c e d u r e s used i n E x -  p e r i m e n t 1 , w h i l e t h e purpose o f t h e second i s t o p r o v i d e the r e a d e r w i t h t h e same i n f o r m a t i o n r e g a r d i n g Experiment 2. SECTION I : METHODS AND PROCEDURES OF EXPERIMENT 1 Subjects Ten male s t u d e n t s , a l l f i r s t team members o f t h e 1976-77  U n i v e r s i t y o f B r i t i s h Columbia w r e s t l i n g squad,  s e r v e d as s u b j e c t s i n E x p e r i m e n t 1 . Apparatus Muscle t e n s i o n was r e c o r d e d u s i n g a Cyborg B L 9 3 3 d u a l d i s t r i b u t i v e p r o c e s s i n g system (Cyborg C o r p o r a t i o n , B o s t o n , Mass.) which c o n s i s t e d o f a B L 9 0 0 p r o c e s s e r and two J 3 3 modules.  Three  (two r e c o r d i n g and one grounding)  p l a s t i c rimmed s i l v e r - p l a t e d e l e c t r o d e s , a l l 1 - i n c h i n diameter,  were used t o r e c o r d EMG a c t i v i t y .  18  19  Experimental  Design  The EMG a c t i v i t y o f the 10 w r e s t l e r s was m o n i t o r e d during s i x d i f f e r e n t sessions.  S e s s i o n s 1 t o 5 took p l a c e  on c o n s e c u t i v e days w h i l e S e s s i o n 6 o c c u r r e d 2 t o 4 days a f t e r S e s s i o n 5*  S e s s i o n s 1,  2 , 3 , 4, and 6 were p r i o r t o  team p r a c t i c e s e s s i o n s w h i l e S e s s i o n 5 was p r i o r t o an i n t e r c o l l e g i a t e w r e s t l i n g competition.  The o b j e c t i v e o f t h e ex-  p e r i m e n t was t o compare t h e EMG a c t i v i t y o f t h e w r e s t l e r s r e c o r d e d p r i o r t o p r a c t i c e s w i t h t h a t r e c o r d e d p r i o r t o the competition.  Thus, t h e d e s i g n was a s i n g l e - g r o u p ,  repeated-  measures d e s i g n w i t h t h e independent v a r i a b l e b e i n g t h e s i x s e s s i o n s and t h e dependent v a r i a b l e s b e i n g t h e i n t e g r a t e d RMS s c o r e s r e c o r d e d from t h e r i g h t forearm f l e x o r and quadr i c e p muscle groups. Procedures Each o f t h e s i x s e s s i o n s began a f t e r a 20-minute group warm-up p e r i o d comprised i b i l i t y exercises.  o f l i g h t , t o t a l body f l e x -  S u b j e c t s were t e s t e d i n d i v i d u a l l y i n the  same o r d e r each day.  T h e r e f o r e , a l t h o u g h t h e r e were d i f -  f e r e n c e s between s u b j e c t s i n t h e i n t e r v a l between t h e end of t h e warm-up s e s s i o n and r e c o r d i n g , t h e i n t e r v a l was r e a s o n a b l y c o n s i s t e n t from s e s s i o n t o s e s s i o n f o r each wrestler. P r i o r t o S e s s i o n 1 t h r e e marks were p l a c e d a t 1 - i n c h i n t e r v a l s on t h e l o n g i t u d i n a l a x i s o f t h e s u r f a c e o f t h e r i g h t f o r e a r m f l e x o r group and a t 5 - i n c h i n t e r v a l s on t h e l o n g i t u d i n a l  20 a x i s of t h e a n t e r i o r s u r f a c e o f the r i g h t q u a d r i c e p muscle group.  A t t h e b e g i n n i n g o f each s e s s i o n the s u b j e c t s were  i n s t r u c t e d t o remain s t a n d i n g w h i l e these s i t e s were p r e p a r e d f o r e l e c t r o d e placement.  P r e p a r a t i o n of these s i t e s  i n c l u d e d s h a v i n g , c l e a n s i n g , and a b r a d i n g the s k i n s u r f a c e t o reduce the s k i n r e s i s t a n c e below 0.2 uV RMS by the s e n s o r l i g h t s on the J 3 3 modules.  as i n d i c a t e d  A grounding e l e c -  t r o d e was p l a c e d between two r e c o r d i n g e l e c t r o d e s on each muscle s i t e .  A f t e r e l e c t r o d e placement the f o l l o w i n g i n -  s t r u c t i o n s were r e a d t o each s u b j e c t : P l e a s e keep y o u r eyes open and l o o k s t r a i g h t ahead. R e s t y o u r arms a c r o s s your t h i g h s but do n o t a l l o w your hands t o t o u c h . P l a c e your l e g s d i r e c t l y out f r o n t of your c h a i r and extend y o u r knees u n t i l you a r e c o m f o r t a b l e . Do n o t c r o s s your l e g s . P l e a s e remain m o t i o n l e s s u n t i l the end o f the t e s t i n g s e s s i o n . The s u b j e c t s were t h e n a l l o w e d a 1-minute a c c l i m a t i z a t i o n p e r i o d a f t e r which the EMG  a c t i v i t y of the r i g h t f o r e a r m  f l e x o r group was m o n i t o r e d f o r one minute. 1-minute i n t e r v a l the EMG  a c t i v i t y of the r i g h t q u a d r i c e p  muscle group was m o n i t o r e d . l e v e l s of RMS EMG  I n the subsequent  The v a l u e s r e c o r d e d were the  a c t i v i t y i n t e g r a t e d over each of the two  1-minute t e s t i n g p e r i o d s . S t a t i s t i c a l Analysis A r e p e a t e d measures a n a l y s i s of v a r i a n c e was  used  t o e v a l u a t e the s i g n i f i c a n c e of t h e . r e s u l t s ( U n i v e r s i t y o f B r i t i s h Columbia computer program, BMD:P2V).  The EMG v a l u e s  21 i  recorded analyzed  from t h e forearm and q u a d r i c e p  muscle groups were  independently.  SECTION H i  METHODS AND PROCEDURES OF EXPERIMENT 2  Subjects Twelve male undergraduate p h y s i c a l e d u c a t i o n e n t s , randomly s e l e c t e d from a group o f v o l u n t e e r s ,  studserved  as s u b j e c t s f o r Experiment 2 . Experimental  Design  Each s u b j e c t was t e s t e d i n d i v i d u a l l y d u r i n g  three  Each s e s s i o n l a s t e d 4-0 minutes and 40  different sessions.  seconds w i t h e x t r a time a l l o t e d f o r e l e c t r o d e placement. There was a t l e a s t 2 4 hours between s e s s i o n s .  During  each  s e s s i o n t h e s u b j e c t s were r e q u i r e d t o p e r f o r m t h e same t h r e e motor t e s t s , 1) Time T e s t , and 3 )  a Hand-Steadiness Test, 2 )  a C h o i c e Response-  a G r i p - S t r e n g t h Test; however, t h e muscle  t e n s i o n l e v e l each s u b j e c t adopted i n h i s r i g h t  forearm  f l e x o r group was d i f f e r e n t d u r i n g each o f t h e t h r e e s e s s i o n s . (Note:  Muscle t e n s i o n was n o t induced  i n the quadricep  muscle group as t h e r e was no' . s i g n i f i c a n t i n c r e a s e i n i t s t e n s i o n as n o t e d i n t h e r e s u l t s s e c t i o n o f Experiment 1 . ) The  s u b j e c t s assumed t h e a p p r o p r i a t e t e n s i o n l e v e l — l o w  (0.5-1.0  uV), medium  (4.5-5-5  w i t h the a i d of biofeedback.  uV),  or high  (9-5-10.5  uV)—  The t e n s i o n l e v e l t h e sub-  j e c t s were r e q u i r e d t o adopt d u r i n g each o f t h e t h r e e  sessions  was d e t e r m i n e d a c c o r d i n g t o a 3 X 6 l a t i n square (Table 2 )  Table 2 L a t i n Square D e s i g n of Experiment 2  \  "Subjects  Session  1  Session M  2  Session H  1 & 7  L  2 & 8  L  H  M  3 &  9  M  L  H  10  M  H  L  5 & 11  H  L  M  6 & 12  H  M  L  &  a  b  tension condition  L=  Low  M=  Medium t e n s i o n  H=  High t e n s i o n c o n d i t i o n  a  b  c  condition  c  3  23 t o ensure the r a n d o m i z a t i o n d e s i g n was  repeated  of any  order e f f e c t s .  This  t w i c e d u r i n g Experiment 2.  A t the b e g i n n i n g  of each of the i n d i v i d u a l t e s t i n g  s e s s i o n s the s u b j e c t s were i n s t r u c t e d t o v i e w the EMG  display  and adopt the a p p r o p r i a t e t e n s i o n l e v e l f o r a 10-minute p e r i o d (biofeedback  period).  D u r i n g the n e x t 5 minutes each  s u b j e c t completed the Hand-Steadiness T e s t .  Following  this  f i r s t t e s t p e r i o d each s u b j e c t assumed the a p p r o p r i a t e l e v e l f o r a n o t h e r 10-minute b i o f e e d b a c k  tension  period before  the  second t e s t , the C h o i c e Response-Time T e s t , t h a t l a s t e d 6 minutes and 4-0 seconds.  The  t h i r d t e s t , the 5-minute  G r i p - S t r e n g t h Test f o l l o w e d a t h i r d 10-minute period.  The  biofeedback  t e m p o r a l sequence f o l l o w e d d u r i n g each t e s t i n g  session i s i l l u s t r a t e d diagrammatically  i n Figure  1.  Procedures A t the b e g i n n i n g t r o d e s were a t t a c h e d  of each t e s t i n g s e s s i o n the e l e c -  t o the r i g h t forearm f l e x o r group  the s u b j e c t s were s e a t e d as i n Experiment 1. c o r d i n g equipment was first  The EMG  and re-  a l s o the same as t h a t used i n the  experiment. D u r i n g the b i o f e e d b a c k  p e r i o d s of each t e s t i n g s e s -  s i o n the s u b j e c t s were i n s t r u c t e d t o c o n t r o l the l e v e l muscle t e n s i o n i n t h e i r r i g h t f o r e a r m f l e x o r group.  of  The  s u b j e c t s a t t a i n e d the d e s i r e d t e n s i o n c o n d i t i o n by w a t c h i n g the EMG values.  meter and a d j u s t i n g the r e a d i n g s  t o the  appropriate  When the s u b j e c t s were t e s t e d under the H i g h  24  F i g u r e 1.  Diagrammatic r e p r e s e n t a t i o n of the t e m p o r a l sequence of events d u r i n g each t e s t i n g s e s s i o n .  25  TEST PERIODS BIOFEEDBACK PERIODS I 1  TOTAL TESTING SESSION  10  5  i  10  r  6:40  10  MINUTES  HAND-STEADINESS TEST  —»10  1—4 50  10  I 50  I 10  I  1—I  I 50  10  50  10  1  50  SECONDS  CHOICE RESPONSE-TIME TEST — i — f — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i — i RESPONSE:  20-SEC INTERVALS  GRIP-STRENGTH TEST  5  55  5  55  5  55  SECONDS  5  55  5  55  26  c o n d i t i o n , t h e y were i n s t r u c t e d t o watch the EMG a d j u s t the t e n s i o n o f the r i g h t forearm  meter and  f l e x o r group u n t i l  the n e e d l e f e l l mid-way "between the l i m i t s o f 9»5 as marked on the s c a l e .  10.5  and  T h i s l e v e l , i . e . 10 uV RMS,  uV  approx-  imates the h i g h e s t t e n s i o n l e v e l s observed i n s u b j e c t s i n E x p e r i m e n t 1.  The  same g e n e r a l p r o c e d u r e s were f o l l o w e d when  the s u b j e c t s were t e s t e d under the Medium o r Low d i t i o n s but,  of course,  the c r i t i c a l  y a l u e s were d i f f e r e n t .  The Medium t e n s i o n v a l u e s were between 4 . 5 the Low  and 5*5  uV.  In  t e n s i o n c o n d i t i o n s u b j e c t s were asked to produce as  low a r e a d i n g as p o s s i b l e . tween 0.5  and  biofeedback to  t e n s i o n con-  1.0  was  uV.  The  T h i s always produced v a l u e s average ' r e s t i n g * l e v e l  approximately  1.2  c o n s i s t e n t l y m a i n t a i n the EMG  uV.  be-  before  A l l s u b j e c t s were a b l e  l e v e l s i n the  appropriate  ranges w i t h the n e e d l e r a r e l y v a r y i n g more t h a n a few of a m i c r o v o l t d u r i n g the b i o f e e d b a c k  periods.  tenths  After  a c h i e v i n g the a p p r o p r i a t e l e v e l o f t e n s i o n and  maintaining  i t f o r e 10 m i n u t e s , each s u b j e c t was  w i t h the  presented  first  of t h r e e motor t e s t s . Test 1:  Hand-Steadiness T e s t .  l o w i n g the f i r s t 10-minute b i o f e e d b a c k were i n s t r u c t e d to p i c k up a 10 I n s t . Co.,  cm  Immediately p e r i o d , the  folsubjects  s t y l u s needle (Lafayette  L a f a y e t t e , Ind.) w i t h a t i p d i a m e t e r of 1 mm  and  p l a c e i t i n a 1.5-mm h o l e i n a s t y l u s r a c k ( L a f a y e t t e I n s t . Co.).  The  s u b j e c t s were i n s t r u c t e d t o keep the s t y l u s n e e d l e  27  i n t h e c e n t r e o f t h e opening a v o i d i n g c o n t a c t w i t h t h e edge. E v e r y time t h e s t y l u s touched t h e s i d e o f t h e opening a d i g i t a l counter corded  ( L a f a y e t t e I n s t . Co., model #58024) r e -  t h e event, w h i l e t h e t o t a l time t h e n e e d l e touched  the s i d e was c u m u l a t i v e l y r e c o r d e d  on a sweep second c l o c k .  There were a t o t a l o f f i v e 10-second t r i a l s admini s t e r e d d u r i n g t h i s Hand-Steadiness T e s t .  Each o f t h e f i v e  t r i a l s was a u t o m a t i c a l l y t e r m i n a t e d by a r e p e a t c y c l e t i m e r ( L a f a y e t t e I n s t . Co., Model #51013) a t which time t h e number of touches and t h e time on t a r g e t f o r t h e p r e c e d i n g p e r i o d were r e c o r d e d .  The s u b j e c t s were n o t p r o v i d e d  any v e r b a l feedback p e r t a i n i n g t o t h e a c c u r a c y performance.  10-second with  of t h e i r  Between each o f t h e f i v e 10-second t e s t i n g  p e r i o d s t h e r e was a 50-second p e r i o d d u r i n g which t h e subj e c t s r e l e a s e d t h e s t y l u s and m a i n t a i n e d  the appropriate  t e n s i o n i n t h e i r forearm b y r e f e r r i n g t o t h e EMG meter. F i g u r e 1 p r o v i d e s a diagrammatic i l l u s t r a t i o n o f t h e sequence of e v e n t s i n v o l v e d i n t h e Hand-Steadiness T e s t . Test 2 :  C h o i c e Response-Time T e s t .  Just p r i o r to  the t e r m i n a t i o n o f t h e second 10-minute b i o f e e d b a c k a pressure  s w i t c h was a t t a c h e d t o t h e e x p e r i m e n t a l  between t h e l e g s o f t h e s u b j e c t .  period chair  I n t h i s p o s i t i o n each sub-  j e c t c o u l d e a s i l y p l a c e h i s r i g h t hand on t h e p r e s s u r e and s t i l l m a i n t a i n t h e a p p r o p r i a t e t e n s i o n l e v e l .  switch  I t was  from t h i s p o s i t i o n t h a t each o f t h e 20 c h o i c e r e s p o n s e - t i m e t r i a l s began.  28 At the end of the second 10-minute b i o f e e d b a c k each s u b j e c t was  period  i n s t r u c t e d to look at a stimulus panel.  The b e g i n n i n g of each of the 20 c h o i c e response-time  trials  was  a u t o m a t i c a l l y s i g n a l l e d by a green w a r n i n g l i g h t f o l l o w e d  1.5  seconds l a t e r by one o f two r e d l i g h t s i n d i c a t i n g which  response was  to take p l a c e .  I f the l i g h t on the r i g h t of the  s t i m u l u s p a n e l appeared, each s u b j e c t p r e s s e d a key to the r i g h t o f a r e a c t i o n time c o n s o l e p o s i t i o n e d a t arm's l e n g t h . I f a l i g h t on the l e f t appeared, the l e f t key on the was p r e s s e d ; was  The  console  sequence o f 10 r i g h t and 10 l e f t responses  d e t e r m i n e d randomly and was  d i f f e r e n t f o r each of the  three t e s t i n g sessions. There were t h r e e d i f f e r e n t measures o f performance on t h i s Choice Response-Time Test: Movement Time, and  3)  1)  R e a c t i o n Time,  T o t a l R e a c t i o n Time.  2)  The v a l u e s f o r  these t h r e e measures were d e t e r m i n e d by two d i g i t a l c l o c k s ( L a f a y e t t e I n s t . Co.,  Model #54517).  Both c l o c k s s t a r t e d  on the p r e s e n t a t i o n o f a r e d l i g h t and the f i r s t as soon as the r i g h t hand was s i t i o n pressure switch.  stopped  l i f t e d from the s t a r t i n g  po-  The r e a d i n g from t h i s c l o c k i n -  d i c a t e d r e a c t i o n t i m e , the time from the s t i m u l u s t o the f i r s t o v e r t movement i n response to the s t i m u l u s . ond c l o c k stopped pressed.  once the a p p r o p r i a t e response key  T o t a l r e a c t i o n time was  The  sec-  was  the time between the p r e -  s e n t a t i o n o f the s t i m u l u s t o the c e s s a t i o n of the second  clock.  R e a c t i o n time was  s u b t r a c t e d from the t o t a l r e a c t i o n  time t o produce movement t i m e , the time from the f i r s t movement t o the c o m p l e t i o n  overt  o f the r e s p o n s e .  A f t e r each o f the 20 t r i a l s each s u b j e c t was i n s t r u c t e d t o r e t u r n h i s r i g h t arm pressure  t o the s t a r t i n g p o s i t i o n  s w i t c h and check the EMG  meter t o i n s u r e t h a t the  EMG  r e a d i n g r e t u r n e d t o the a p p r o p r i a t e l e v e l .  One  was  i n i t i a t e d every 20 seconds, t h e r e f o r e the e n t i r e C h o i c e  Response-Time Test l a s t e d 6 minutes and 4-0 seconds  trial  (see  Figure 1). Test 3 :  I n the f i n a l 30 seconds  Grip-Strength Test.  o f the t h i r d 10-minute b i o f e e d b a c k  period a grip adjustable  hand dynamometer ( L a f a y e t t e I n s t . Co.,  Model #76618)  p l a c e d i n the r i g h t hand of each s u b j e c t .  The  s u b j e c t s were  i n s t r u c t e d t o squeeze the dynamometer as f o r c e f u l l y sible  on the p r e s e n t a t i o n o f a 5-second cue l i g h t  S t o e l t i n g Co.,  Model 20104, C h i c a g o , 111.)  t h i s c o n t r a c t i o n u n t i l the l i g h t was o f the f o r c e o f c o n t r a c t i o n was r e c o r d e d by a c h a r t r e c o r d e r . o f the p a t t e r n was t r i a l producing  as pos(C.H.  and t o s u s t a i n  extinguished.  A pattern  e l e c t r i c a l l y transduced The  and  highest c o n t r a c t i o n value  s u b t r a c t e d from the l o w e s t d u r i n g each  a measure of f a t i g u e .  o f each t r i a l was  was  recorded  Maximal c o n t r a c t i o n  from the dynamometer f a c e .  t h e r e were two measures of s t r e n g t h f o r each t r i a l . 5 - s e c o n d t r i a l s were a d m i n i s t e r e d  Thus, Five  w i t h f o u r 55-second b i o -  30  feedback p e r i o d s i n t e r j e c t e d between the t r i a l s  (see F i g u r e  1). S t a t i s t i c a l Analysis A mean over t r i a l s f o r each o f t h e t h r e e t e n s i o n c o n d i t i o n s on the two measures o f hand s t a b i l i t y , measures o f speed o f response,  and the two measures o f g r i p  s t r e n g t h were computed f o r each s u b j e c t . then independently  the three  These means were  s u b j e c t e d t o a m u l t i v a r i a t e and u n i v a r i a t e  a n a l y s i s o f v a r i a n c e ( F i n n , 1972) t o a s s e s s the s i g n i f i c a n c e of the v a r i a t i o n i n scores.  This a n a l y s i s r e s u l t e d i n a  m u l t i v a r i a t e F r a t i o which i n d i c a t e d the o v e r a l l s i g n i f i c a n c e o f each o f t h e t h r e e t e s t s w h i l e p r e - p l a n n e d  orthogonal  c o n t r a s t s were performed on each measure o f the t h r e e  tests.  The means r e c o r d e d i n the Low c o n d i t i o n were compared w i t h the means o f t h e Medium and High c o n d i t i o n s combined, and the Medium c o n d i t i o n was compared w i t h the H i g h .  Chapter 4 RESULTS AND  DISCUSSION  R e s u l t s of Experiment 1 Figure 2 c l e a r l y indicates of EMG  t h a t the o v e r a l l l e v e l  a c t i v i t y was g r e a t e r i n the f o r e a r m f l e x o r group  i n the q u a d r i c e p muscle group.  than  I t i s a l s o c l e a r from t h i s  f i g u r e t h a t the muscle t e n s i o n of the f o r e a r m f l e x o r i n c r e a s e d a p p r e c i a b l y p r i o r t o the c o m p e t i t i o n b u t the  EMG  a c t i v i t y of the q u a d r i c e p s d i d n o t . S t a t i s t i c a l analysis these d i f f e r e n c e s .  c o n f i r m e d the s i g n i f i c a n c e  I n o r d e r t o determine the  of the o v e r a l l d i f f e r e n c e  i n EMG  of  significance  l e v e l s between the forearm  f l e x o r and q u a d r i c e p muscle groups, the mean EMG  levels  f o r b o t h s i t e s were computed f o r each s u b j e c t over the s i x s e s s i o n s (see Table 3 ) -  The average s c o r e s o f the f o r e a r m  f l e x o r s were h i g h e r than the average s c o r e s of the q u a d r i c e p muscles f o r a l l t e n s u b j e c t s ( s i g n t e s t , N=10,  X=0,  p=0.002).  I n f a c t , t h e r e was o n l y one i n s t a n c e d u r i n g the e n t i r e iment when the EMG  exper-  v a l u e r e c o r d e d from the q u a d r i c e p muscles  was h i g h e r t h a n t h a t r e c o r d e d from the f o r e a r m f l e x o r s . l a r g e i n c r e a s e i n EMG  a c t i v i t y o f the f o r e a r m f l e x o r s  The  on  S e s s i o n 5 i p r i o r t o the c o m p e t i t i o n , was r e f l e c t e d i n a s i g 31  32  Figure  2.  P r e - p r a c t i c e and p r e - c o m p e t i t i o n levels of muscle t e n s i o n i n the f o r e a r m f l e x o r and q u a d r i c e p muscle groups. Each p o i n t r e p r e s e n t s the mean RMS EMG a c t i v i t y i n t e g r a t e d over the e n t i r e 1-minute t e s t i n g session.  33  3k  Table 3 EMG A c t i v i t y o f t h e Forearm and Quadricep Muscles Recorded D u r i n g t h e S i x T e s t i n g S e s s i o n s ^  Sessions  _  _  _  Subjects  arm l e g  arm l e g  arm l e g  arm l e g  arm l e g  arm l e g  51  2 . 4 1.2  3 . 1 1.4  2 . 1 1.4  1.3  0.8  4 . 5 1.1  2.1  1.3  5  1.3  0.6  0.9 0.6  0 . 9 0.7  2.3 0.6  6 . 1 1.0  '1.4  0.7  53  5 . 0 0.8  1.9 0.8  2.0 0.7  6.4 0.7  7.8 1.4  2.7  0.9  Sjj.  1.71.1  1.50.9  1.40.7  1.90.9  2.30.7  1.1  0.6  55  1.8 0 . 6  1.3  0.6  3.4 0.6  5.0 0.6  6.7 0.5  3.3  0.5  56  1.5  1.1  1.4 0.8  2 . 5 1.4  1.4 1.2  1.8 1.7  0 . 9 0.8  Sy  4 . 0 0.6  3 . 6 1.0  2.6 0.7  2.7 1.0  3 . 5 1.0  1.7 0 . 9  SQ  5-02.1  2.41.8  1.90.7  2.51.9  6.30.6  3.01.2  S  9  2.30.8  2.50.6  2.40.7  1.40.5  4 . o o . 6 ; 2'.2  S  1 0  2  1  '  6  1'5  1  '7  1.5  1.2  1.3  _  .  1.8 1.0  _  2 . 9 1.0  _  0.7  1.7 1.2  Mean  2 . 6 1.1  2 . 0 1.0  2.0 0.9  2.7 0.9  4 . 6 1.0  2.0  0.9  S.D.  1.5  0.9 0.4  0.7 0.3  1.7  2.0 0.4  0.8  0.3  0.5  0.4  Each number i s t h e mean RMS EMG l e v e l i n uV i n t e g r a t e d over t h e e n t i r e 1-minute t e s t i n g s e s s i o n  35  n i f i c a n t v a r i a t i o n i n t h e EMG a c t i v i t y o f the forearm over t h e s i x t e s t i n g s e s s i o n s (Table 4,  ^=9.86,  whereas t h e v a r i a t i o n i n t h e EMG o f t h e q u a d r i c e p s was n o t s i g n i f i c a n t (Table 5» F^ ^ = 0 . 0 5 8 ,  flexor  p=0.0005), muscles  p=0.656).  D i s c u s s i o n of Experiment 1 The purpose o f Experiment 1 was t o p r o v i d e  support  f o r t h e h y p o t h e s i s t h a t muscle t e n s i o n l e v e l s o f c o m p e t i t i v e a t h l e t e s a r e elevated immediately  p r i o r to competition. A l -  though s u b j e c t i v e r e p o r t s o f t h e a n x i e t y e x p e r i e n c e d b y many a t h l e t e s p r i o r t o a c o m p e t i t i v e event and t h e e x t e n s i v e  lit-  e r a t u r e documenting t h e r e l a t i o n between s u b j e c t i v e s t a t e s o f a n x i e t y and i n c r e a s e d muscle t e n s i o n ( c f . S e l y e , 1974) supp o r t e d such a view, t h e r e were no d i r e c t l y r e l e v a n t e m p i r i c a l data. Thus, Experiment 1 p r o v i d e s t h e f i r s t e m p i r i c a l evidence  c o n f i r m i n g t h e commonly h e l d view ( c f . Zaichowsky,  1974) t h a t i n c r e a s e s i n muscle t e n s i o n o c c u r i n a t h l e t e s p r i o r t o a c o m p e t i t i v e event.  A number o f r e s e a r c h e r s have  found t h a t a v a r i e t y o f s t r e s s f u l s i t u a t i o n s c a n cause a n i n c r e a s e i n muscle t e n s i o n ; however, no s t u d i e s o f t h i s  nature  have been conducted w i t h e x p e r i e n c e d a t h l e t e s i n a c t u a l competitive situations.  Although  t h e e x t r a p o l a t i o n from s t r e s s f u l  l a b o r a t o r y s i t u a t i o n s t o t h e c o m p e t i t i v e atmosphere o f the p l a y i n g f i e l d may seem j u s t i f i e d , t h e r e a r e two reasons why such g e n e r a l i z a t i o n s can be q u e s t i o n e d .  Firstly,  experienced  Table 4 ANOVA T a b l e f o r t h e Forearm F l e x o r Muscle S i t e  Degrees o f freedom  Mean Square (uV)  Subjects  9  5.2  Sessions  5  9-9  45  1.2  Source  Error  F  9.860  Prob. F exceeded  0.000  Table 5 ANOVA T a b l e f o r t h e Quadricep Muscle S i t e  S ourc e  Degrees o f freedom  Mean Square (uV)  Subjects  9  0.5  Sessions  5  0.1  45  0.1  Error  F  0.058  Prob. F exceeded  0.656  37  c o m p e t i t i v e a t h l e t e s may e v e n t u a l l y h a b i t u a t e t o c o m p e t i t i v e s i t u a t i o n s , thereby producing  low l e v e l s o f muscle t e n s i o n  even though t h e y a r e i n a s t r e s s f u l c o m p e t i t i v e S e c o n d l y , those a t h l e t e s t h a t do e x p e r i e n c e  atmosphere.  marked  increases  i n muscle t e n s i o n i m m e d i a t e l y p r i o r t o c o m p e t i t i o n may have d i f f i c u l t y becoming s u c c e s s f u l c o m p e t i t i v e a t h l e t e s , b e i n g e l i m i n a t e d by a p r o c e s s o f n a t u r a l s e l e c t i o n . However, the f i n d i n g s o f Experiment 1 have i n d i c a t e d t h a t , a t l e a s t i n some i n s t a n c e s , e x p e r i e n c e d marked p r e - c o m p e t i t i o n  c o m p e t i t i v e a t h l e t e s do d i s p l a y  i n c r e a s e s i n t h e EMG a c t i v i t y o f some  of t h e i r m u s c l e s . Experiment 1 a l s o confirmed corded simultaneously the same.  t h a t t h e EMG a c t i v i t y r e -  from d i f f e r e n t s i t e s i s n o t n e c e s s a r i l y  As w e l l as f i n d i n g t h a t t h e EMG a c t i v i t y o f t h e  f o r e a r m f l e x o r group was g e n e r a l l y h i g h e r t h a n t h a t o f t h e quadricep creased  muscle group, t h e EMG a c t i v i t y o f t h e f o r e a r m i n -  s i g n i f i c a n t l y i n the pre-competition  the a c t i v i t y o f the q u a d r i c e p  d i d not.  i n t e r v a l while  Both of these obser-  v a t i o n s are c o n s i s t e n t w i t h previous r e p o r t s . -Alexander (1975)»  f o r example, found t h a t t h e peak-to-peak EMG a c t i v i t y  of t h e f o r e a r m muscles was s i g n i f i c a n t l y h i g h e r than t h a t o f the l e g , and t h a t t h e EMG a c t i v i t y o f t h e f o r e a r m f l u c t u a t e d s i g n i f i c a n t l y d u r i n g EMG b i o f e e d b a c k r e l a x a t i o n s e s s i o n s w h i l e t h e a c t i v i t y i n t h e l e g remained unchanged. gested  He sug-  t h a t t h e EMG a c t i v i t y o f t h e l e g was so low t h a t i t  38  was d i f f i c u l t t o demonstrate f u r t h e r r e d u c t i o n s .  However,  t h i s does n o t e x p l a i n why i n c r e a s e s i n q u a d r i c e p EMG  activity  comparable t o those r e c o r d e d from the f o r e a r m were n o t obs e r v e d i n Experiment 1. Such major d i f f e r e n c e s between the EMG  a c t i v i t y of  d i f f e r e n t muscles have b o t h t h e o r e t i c a l and p r a c t i c a l implications.  I n most t h e o r i e s of the r e l a t i o n between muscle .  t e n s i o n and performance, such as t h e well-known i n v e r t e d - U h y p o t h e s i s ('Stauffacher, 1937). muscle t e n s i o n i s a u n i t a r y concept; t h e r e i s no attempt t o r e l a t e l e v e l s of muscle t e n s i o n t o p a r t i c u l a r muscle groups. the  However, on the b a s i s o f  present observations, i t i s c l e a r that r e l a x i n g or t e n s i n g  one muscle group does n o t n e c e s s a r i l y produce s i m i l a r i n o t h e r muscles of the body.  changes  Therefore, future attempts  to use the concept o f muscle t e n s i o n t o e x p l a i n o r p r e d i c t b e h a v i o u r s h o u l d be based on t h e u n d e r s t a n d i n g t h a t s p e c i f i c l e v e l s of muscle t e n s i o n a r e a p p a r e n t l y c h a r a c t e r i s t i c o f i n d i v i d u a l muscles, not i n d i v i d u a l s u b j e c t s . The major p r a c t i c a l i m p l i c a t i o n o f the f i n d i n g t h a t d i f f e r e n t muscles may have d i f f e r e n t muscle t e n s i o n l e v e l s i s t h a t any a t t e m p t s t o improve a t h l e t i c performance by cont r o l l i n g muscle t e n s i o n i n the p r e - c o m p e t i t i v e p e r i o d should be d i r e c t e d a t the a c t i v i t y of the muscle groups p r e d o m i n a n t l y i n v o l v e d i n the event i n q u e s t i o n and those which have e l e v a t e d l e v e l s o f EMG  a c t i v i t y p r i o r to competition.  39  R e s u l t s of Experiment 2 The  r e s u l t s i n d i c a t e d t h a t h i g h l e v e l s of muscle  t e n s i o n p r i o r t o t e s t i n g d i s r u p t e d the performance of H a n d - S t e a d i n e s s and  the G r i p - S t r e n g t h  the  T e s t s , whereas the  e f f e c t of muscle t e n s i o n on the C h o i c e Response-Time T e s t was  equivocal.  reported  The  r e s u l t s o f the t h r e e motor t e s t s a r e  i n d i v i d u a l l y i n separate  d i v i d u a l section includes  1)  s e c t i o n s below.  a graphic  Each i n -  representation  of  the r e l a t i o n s h i p between the means of the measures d e r i v e d from the t e s t i n q u e s t i o n and t a b l e of the means and 3)  s c o r e s , and  o v e r a l l t e s t and T e s t 1:  the t e n s i o n l e v e l ,  standard  a t a b l e of the s i g n i f i c a n c e v a l u e s f o r the o r t h o g o n a l  The  r e s u l t s of  i n F i g u r e 3 and  6 w h i l e the r e s u l t s of the s t a t i s t i c a l a n a l y s e s  w i t h the edge and  Table pre-  time on t a r g e t ) i n d i c a t e s t h a t performance t e n s i o n c o n d i t i o n and w o r s t i n the H i g h Thus the m u l t i v a r i a t e F was  n i f i c a n t (F^ 3=12.89, p=0.0015). f  are  the  Each of the two measures ( i . e . c o n t a c t s  b e s t i n the Low  tension condition.  f o r the  contrasts.  Hand-Steadiness T e s t .  s e n t e d i n Table 7.  a  d e v i a t i o n s of the t e s t  Hand-Steadiness T e s t are i l l u s t r a t e d  was  2)  The  highly  comparison of Low  sigten-  s i o n c o n d i t i o n w i t h the Medium and High c o n d i t i o n s combined was  s i g n i f i c a n t f o r b o t h measures of hand  steadiness,  ( c o n t a c t s w i t h edge, p = 0 . 0 0 0 1 ; time on t a r g e t , p = 0 . 0 0 0 l ) ; whereas, t h e r e was  a s i g n i f i c a n t d i f f e r e n c e between the  40  F i g u r e 3«  R e l a t i o n "between performance on the Hand-Steadiness T e s t and a n t e c e d e n t l e v e l s o f muscle t e n s i o n . Each p o i n t r e p r e s e n t s the average of 12 s u b j e c t s over 5 t r i a l s . (Note: the " c o n t a c t s w i t h edge" s c a l e i s i n v e r t e d . )  4l  Table 6 Means and. S t a n d a r d D e v i a t i o n s f o r t h e Two Measures o f Hand S t e a d i n e s s ( i . e . C o n t a c t s W i t h Edge and Time On T a r g e t ) .  Tension condition  C o n t a c t s w i t h edge  Time on t a r g e t ( s e c . )  Mean  S.D.  Mean  S .D.  L  13-7  8.23  8.75  0.82  M  18.9  5.99  8.06  0.82  H  22.1  5.92  7.82  0.67  Table 7 P r o b a b i l i t y Values f o r the Hand-Steadiness.Test p values Contrasts  C o n t a c t s w i t h edge  Time on t a r g e t  L v s M-H  0.0001  0.0001  M vs H  0.0112  0.3295  Multivariate Fij, =12.89, > 8  p=0.0015  43 Medium and High c o n d i t i o n s i n terms of the c o n t a c t s w i t h edge measure (p=0.0l), h u t n o t i n terms o f the t i m e - o n - t a r g e t measure  (p=0.3295). Test 2:  Choice Response-Time T e s t .  F i g u r e 4 and  Table 8 p r e s e n t the means o f the t h r e e measures of the C h o i c e Response-Time Test ( i . e . r e a c t i o n t i m e , movement time, and t o t a l r e a c t i o n time) as a f u n c t i o n of the l e v e l o f muscle t e n s i o n .  A l t h o u g h the m u l t i v a r i a t e F r a t i o was  signif-  i c a n t (Table 9, Fg g = l l . l 6 , p=0.0049), a l l t h r e e p a i r s of o r t h o g o n a l c o n t r a s t s were n o t (see Table 9 ) •  However,  the f a s t e s t average responses f o r each o f the t h r e e measures were r e c o r d e d i n the Medium t e n s i o n c o n d i t i o n . Test 38  Grip-Strength Test.  The r e s u l t s o f the  G r i p - S t r e n g t h Test a r e i l l u s t r a t e d i n F i g u r e 5 and Table 10 w h i l e the r e s u l t s o f the s t a t i s t i c a l a n a l y s e s a r e p r e sented i n Table 11.  Each of the two measures o f g r i p  s t r e n g t h ( i . e . maximum s c o r e and f a t i g u e ) i n d i c a t e d t h a t performance was b e s t i n the Low t e n s i o n c o n d i t i o n and worst i n the Medium and High c o n d i t i o n s . Thus, the m u l t i v a r i a t e F was h i g h l y s i g n i f i c a n t ( F ^ 3=6.61, p=0.0119).  The o n l y  s i g n i f i c a n t o r t h o g o n a l c o n t r a s t was t h a t between the Low v e r s u s the combined Medium and High c o n d i t i o n s on the maximum s t r e n g t h measure (p=0.0003).  The Medium v e r s u s H i g h  c o n t r a s t s o f t h i s same measure j u s t f a i l e d t o reach  signif-  44  F i g u r e 4.  R e l a t i o n between performance on the C h o i c e Response-Time T e s t and a n t e c e d e n t l e v e l s of muscle t e n s i o n . Each p o i n t r e p r e s e n t s the average of 12 s u b j e c t s over 20 t r i a l s spaced 20 seconds a p a r t .  45  0.5  o cu  CO  CO 0.4  TOTAL REACTION  A — A  o  REACTION  Q-  TIME  TIME  co MOVEMENT TIME  LU  OC  CL CO  0.3  Low  Medium  TENSION CONDITION  High  46  Table 8 Means and S t a n d a r d D e v i a t i o n s ( i n Seconds) F o r t h e Three Measures o f Speed o f Response  Tension condition  R e a c t i o n time  Movement time  T o t a l time  Mean  S.D.  Mean  S.D.  Mean  S.D.  L  .259  .036  .236  .052  .495  .082  M  .249  .037  .225  .046  .483  .075  H  .258  .033  .228  .041  .488  .064  Table 9 P r o b a b i l i t y V a l u e s f o r t h e C h o i c e Response-Time  Test  p values Contrasts  R e a c t i o n time  Movement time  T o t a l time  L v s M-H  0.1530  0.1298  0.1037  M vs H  0.0880  0.9142  0.4562  Multivariate F  6  6=11.16,  p=0.0049  47  F i g u r e 5-  R e l a t i o n between performance on the G r i p - S t r e n g t h T e s t and a n t e c e d e n t l e v e l s of muscle t e n s i o n . Each p o i n t r e p r e s e n t s the average of 12 s u b j e c t s over 5 t r i a l s . (Note: the " f a t i g u e " scale i s inverted.)  48  49  Table 10 Means and S t a n d a r d D e v i a t i o n s ( i n K i l o g r a m s ) F o r t h e Two Measures o f G r i p S t r e n g t h  Maximum s c o r e  Fatigue score  Mean  S.D.  Mean  S.D.  L  50.3  6.41  0.79  2.32  M  47.3  6.83  3.52  6.84  H  ^5-7 •  4.82  2.91  4.19  Tension Condition  Table 11 P r o b a b i l i t y Values f o r the G r i p - S t r e n g t h Test  p value Contrasts  Maximum s c o r e  Fatigue score  L v s M«H  0.0003  0.0898  M vs H  O.O969  0.7423  Multivariate F  4 ) 8  = 6 . 6 l , p=0.0119  50  icance  (p=0.0969).  Both orthogonal  c o n t r a s t s of the f a t i g u e  measure f a i l e d t o reach s i g n i f i c a n c e . D i s c u s s i o n o f Experiment 2 I n Experiment 1 muscle t e n s i o n l e v e l s as h i g h as 10 uV RMS were observed i n c o l l e g i a t e w r e s t l e r s one hour p r i o r to a competitive  event.  However, a l l p r e v i o u s s t u d i e s o f the  r e l a t i o n s h i p between muscle t e n s i o n and performance  included  h i g h t e n s i o n c o n d i t i o n s r a n g i n g from one e i g h t h t o maximal contraction.  Such l e v e l s of c o n t r a c t i o n produced  of 100 t o 1000 uV RMS  on.the a p p a r a t u s employed i n the p r e -  sent t h e s i s , f a r above the h i g h e s t l e v e l s recorded p e r i m e n t 1.  readings  Thus, a l t h o u g h  i n Ex-  t h e r e are many r e p o r t s i n the  l i t e r a t u r e t h a t h i g h muscle t e n s i o n l e v e l s can d i s r u p t p e r ( c f . R u s s e l l , 1932), t h e r e i s l i t t l e ,  formance  i f any,  e v i d e n c e t h a t such d i s r u p t i o n can be produced by i n EMG  a c t i v i t y w i t h i n the normal r e s t i n g range.  increases Therefore,  the purpose o f Experiment 2 was t o determine whether such i n c r e a s e s i n muscle t e n s i o n c o u l d cause a d i s r u p t i o n i n the performance of the t h r e e motor  tasks.  The r e l a t i o n between a n t e c e d e n t l e v e l s o f muscle t e n s i o n and performance was the same f o r b o t h the HandSteadiness  and G r i p - S t r e n g t h  Tests.  I n b o t h c a s e s medium  and h i g h l e v e l s of p r e - t r i a l muscle t e n s i o n were a s s o c i a t e d w i t h poor performance.  The r e s u l t s of the C h o i c e Response-  Test,were e q u i v o c a l ; none of the o r t h o g o n a l significant.  contrasts  was  51  A l t h o u g h i t i s d i f f i c u l t t o d i r e c t l y a p p l y the r e s u l t s of l a b o r a t o r y t e s t s of motor performance t o r e a l compe t i t i v e s i t u a t i o n s , there are three reasons f o r suspecting t h a t the s i g n i f i c a n t d i s r u p t i o n o f performance produced by h i g h l e v e l s of muscle t e n s i o n i n t h i s experiment may  perhaps  be even l e s s than t h a t o c c u r r i n g d u r i n g some a t h l e t i c competitions . F i r s t l y , i n E x p e r i m e n t 1,  the EMG  a c t i v i t y o f the  w r e s t l e r s was m o n i t o r e d a p p r o x i m a t e l y 1 hour b e f o r e r a t h e r t h a n i m m e d i a t e l y p r i o r t o t h e i r matches. t h a t EMG  I f one assumes  l e v e l s i n c r e a s e w i t h the approach o f impending  c o m p e t i t i o n , t h e r e i s r e a s o n t o b e l i e v e t h a t the h i g h e s t muscle t e n s i o n l e v e l s r e c o r d e d i n Experiment 1,  and r e p r o -  duced i n Experiment 2, were l o w e r than those which would a c t u a l l y o c c u r i n the c r i t i c a l p e r i o d j u s t b e f o r e c o m p e t i t i o n . S e c o n d l y , i n Experiment 2, performance was  disrupted  a f t e r r e l a t i v e l y s h o r t p e r i o d s of i n d u c e d muscle t e n s i o n . These p e r i o d s ranged from 10 minutes f o r the Hand-Steadiness T e s t t o 40 minutes f o r the G r i p - S t r e n g t h T e s t .  However,  many a t h l e t e s , i n c l u d i n g the w r e s t l e r s o f the f i r s t e x p e r iment, have commented t h a t t h e y seem tense days b e f o r e " b i g " events. T h i r d l y , the t e s t s used i n Experiment 2 were s i m p l e i n comparison t o the complex a c t i v i t i e s i n v o l v e d i n most s p o r t i n g e v e n t s . 'The r e s u l t s o f many e x p e r i m e n t s have e s t a b l i s h e d t h a t the performance of s i m p l e t a s k s i s more d i f -  52  f i c u l t t o d i s r u p t than i s the performance of more complex tasks. Thus, the r e s u l t s of Experiment 2 s t r o n g l y suggest., t h a t the e l e v a t e d muscle t e n s i o n l e v e l s e x p e r i e n c e d by a t h l e t e s p r i o r t o a c o m p e t i t i v e event may d i s r u p t t h e i r performance. GENERAL DISCUSSION The g e n e r a l purpose of t h i s t h e s i s was t o determine whether f u t u r e r e s e a r c h i n v o l v i n g EMG b i o f e e d b a c k as a p r e c o m p e t i t i o n muscle r e l a x a t i o n t e c h n i q u e f o r c o m p e t i t i v e a t h l e t e s was w a r r a n t e d .  More s p e c i f i c a l l y the g o a l s were  f i r s t t o determine i f t h e r e were i n c r e a s e s i n the muscle t e n s i o n o f competing a t h l e t e s p r i o r t o c o m p e t i t i o n e v e n t s , and second t o determine whether such i n c r e a s e s c o u l d a f f e c t the  performance of motor t a s k s .  The r e s u l t s of Experiment 1  e s t a b l i s h e d t h a t a s i g n i f i c a n t i n c r e a s e i n the l e v e l s of muscle t e n s i o n of the r i g h t f o r e a r m f l e x o r group d i d o c c u r i n a t h l e t e s p r i o r t o a competion e v e n t .  I n Experiment 2 such  i n c r e a s e s i n muscle t e n s i o n d i s r u p t e d the performance of b o t h the  Hand-Steadiness and G r i p - S t r e n g t h T e s t s .  Thus, the  r e s u l t s o f the p r e s e n t t h e s i s j u s t i f y f u t u r e r e s e a r c h i n t o the  use o f the EMG b i o f e e d b a c k r e l a x a t i o n t e c h n i q u e ; a  t e c h n i q u e w h i c h w i l l h o p e f u l l y reduce c o m p e t i t i v e a t h l e t e s * p r e - c o m p e t i t i o n muscle t e n s i o n l e v e l s t h e r e b y i m p r o v i n g t h e i r a t h l e t i c performance.  5 3  Methodological Innovations The'experiments c o m p r i s i n g the p r e s e n t t h e s i s d i f f e r e d from p r e v i o u s s t u d i e s o f t h e , r e l a t i o n between muscle t e n s i o n and performance i n s e v e r a l i m p o r t a n t ways.  Although  t h e e f f e c t i v e n e s s o f EMG b i o f e e d b a c k as a method o f c o n t r o l l i n g EMG a c t i v i t y i n c l i n i c a l s i t u a t i o n s had been w e l l e s t a b l i s h e d , i t had n e v e r been used as a " r e s e a r c h " t o o l i n the s t u d y o f t h e r e l a t i o n s h i p between muscle t e n s i o n and p e r formance.  The use o f t h i s b i o f e e d b a c k t e c h n i q u e i n E x p e r i -  ment 2 p r o v i d e d a method o f v a r y i n g muscle t e n s i o n l e v e l s , f a r more a c c u r a t e than methods used by p r e v i o u s i n v e s t i g a t o r s . The p r e c i s i o n o f the s t u d y was a l s o improved by u s i n g the s e n s i t i v e RMS measure o f EMG a c t i v i t y .  This recording tech-  n i q u e had n o t been p r e v i o u s l y used i n i n v e s t i g a t i o n s o f EMGbehaviour  relations.  The p r e s e n t s t u d i e s a p p a r e n t l y comprise  the f i r s t  attempt t o s t u d y the r e l a t i o n s h i p between muscle t e n s i o n and performance i n such a way t h a t t h e r e s u l t s can be d i r e c t l y a p p l i e d t o t h e p r a c t i c a l problem performance.  of improving a t h l e t i c  T h i s was a c c o m p l i s h e d b y t h e a d o p t i o n o f  several methodological innovations s p e c i f i c a l l y  designed  to i n c r e a s e t h e a p p l i c a b i l i t y o f t h e r e s u l t s o f the experiments. monitored  Muscle t e n s i o n l e v e l s o f c o m p e t i t i v e a t h l e t e s were i n t h e a c t u a l c o m p e t i t i v e s i t u a t i o n i n Experiment  1, and t h e e f f e c t s o f "normal"  v a r i a t i o n s i n muscle t e n s i o n  on s p o r t - r e l a t e d t a s k s were s t u d i e d i n Experiment  2; whereas,  p r e v i o u s i n v e s t i g a t o r s i n t h i s a r e a have used s u b j e c t s s e l e c t e d from the s t u d e n t p o p u l a t i o n a t l a r g e t o s t u d y t h e e f f e c t s o f extreme l e v e l s o f muscle t e n s i o n on a r b i t r a r y motor and m e n t a l t a s k s , always i n l a b o r a t o r y s i t u a t i o n s . Moreover, t h e muscle t e n s i o n l e v e l s s t u d i e d i n Experiment 2 were i n d u c e d p r i o r t o t h e performance o f t h e b e h a v i o u r a l tests.  A l t h o u g h t h e e f f e c t o f h i g h l e v e l s o f muscle t e n s i o n  on performance i s p r o b a b l y more d i s r u p t i v e when t e n s i o n i s induced and e x p e r i m e n t a l t a s k s a r e performed a t t h e same t i m e , t h e r e i s l e s s o p p o r t u n i t y f o r a p p l y i n g t h e r e s u l t s from such procedures to a c t u a l a t h l e t i c  competition.  M u s c l e T e n s i o n and S u b j e c t i v e T e n s i o n The word " t e n s i o n " i s commonly used i n two d i f f e r e n t contexts.  I t i s used t o d e s c r i b e the s t a t e o f an i n d i v i -  d u a l ' s muscles o r h i s mental o r s u b j e c t i v e s t a t e .  The f a c t  t h a t a s i n g l e term i s used i n b o t h cases emphasizes t h e common tendency i n everyday s i t u a t i o n s t o equate s u b j e c t i v e and m u s c u l a r t e n s i o n and t h e tendency i n c l i n i c a l o r e x p e r i m e n t a l c o n t e x t s t o use measures o f muscle t e n s i o n as a b a s i s f o r i n f e r r i n g t h e n a t u r e o f an i n d i v i d u a l ' s s u b j e c t i v e state.  However, t h e r e l a t i o n between muscular and s u b j e c -  t i v e t e n s i o n i s n o t a s i m p l e one, and t h u s , a d i s c u s s i o n o f the  r e l a t i o n between these two c o n d i t i o n s i s w a r r a n t e d here  to c l a r i f y t h e i m p l i c a t i o n s o f the p r e s e n t s t u d i e s . One o f the main reasons f o r e q u a t i n g muscle t e n s i o n with subjective tension i s that a c h r o n i c a l l y high l e v e l of  55-  muscle t e n s i o n i s one  of the many p e r i p h e r a l symptoms f r e -  q u e n t l y observed i n s u b j e c t s c o m p l a i n i n g s u b j e c t i v e t e n s i o n or a n x i e t y .  of h i g h l e v e l s of  F o r example, the s o - c a l l e d  t e n s i o n headache which i s assumed to r e s u l t from the e f f e c t s of h i g h l e v e l s of m u s c u l a r t e n s i o n o f - t h e f r o n t a l i s muscle, f r e q u e n t l y r e c u r s i n s u s c e p t i b l e p a t i e n t s o n l y when t h e y have been s u b j e c t e d Stoyva,  to s t r e s s f u l s i t u a t i o n s (Budzynski,  & A l d e r , 1970).  Perhaps the most common p r a c t i c a l  a p p l i c a t i o n of the r e l a t i o n between muscle t e n s i o n and j e c t i v e t e n s i o n i s the s o - c a l l e d p o l y g r a p h test.  sub-  or l i e d e t e c t o r  B a s i c a l l y t h i s t e s t i n v o l v e s r e c o r d i n g a number of  p h y s i o l o g i c a l c o r r e l a t e s of s u b j e c t i v e t e n s i o n o r a n x i e t y i n a c o n t r o l l e d s i t u a t i o n i n which o t h e r f a c t o r s which  can  i n f l u e n c e these measures a r e " c o n t r o l l e d " . P r i o r t o i n t e r r o g a t i o n the s u b j e c t i s seated and i s i n s t r u c t e d t o r e l a x .  i n a comfortable  The  position  assumption i s t h a t i n such  c o n t r o l l e d s i t u a t i o n s , the s u b j e c t i v e t e n s i o n a s s o c i a t e d w i t h t e l l i n g a l i e w i l l be r e f l e c t e d i n i n c r e a s e d EMG i v i t y and changes i n o t h e r p e r i p h e r a l measures.  The  actvalidity  of t h i s assumption has been u p h e l d i n a v a r i e t y of l a b o r a t o r y t e s t s ( c f . Smith, 1967)• Because t h e r e are c o r r e l a t i o n s between r e s t i n g l e v e l s and  s u b j e c t i v e s t a t e s of anxiety or tension,  EMG  there  has been a tendency t o assume t h a t the two are c a u s a l l y r e lated.  W h i l e t h e r e i s no doubt t h a t i n c r e a s e s i n s u b j e c t i v e  t e n s i o n of an i n d i v i d u a l can r e l i a b l y produce i n c r e a s e s i n  56 muscle t e n s i o n when o t h e r f a c t o r s which c a n i n f l u e n c e muscle tension are held constant,  t h e r e i s no e v i d e n c e t h a t changes  i n r e s t i n g EMG l e v e l s can d i r e c t l y produce changes i n l e v e l s of a n x i e t y .  Apparently,  at l e a s t with respect to tension,  the b r a i n c o n t r o l s t h e muscles and n o t v i c e v e r s a .  Never-  t h e l e s s , s e v e r a l i n v e s t i g a t o r s have t r i e d t o reduce a n x i e t y by u s i n g b i o f e e d b a c k t o reduce EMG a c t i v i t y .  The f u t i l i t y  of t h e approach i s ' demonstrated by t h e study o f R a s k i n e t al.  (1973)'  They used an EMG b i o f e e d b a c k t e c h n i q u e  t o reduce  the f r o n t a l i s muscle t e n s i o n l e v e l s o f 10 s u b j e c t s c l a s s e d as c h r o n i c a l l y tense i n d i v i d u a l s . The r e d u c t i o n o f f r o n t a l i s muscle t e n s i o n reduced t h e i n c i d e n c e o f t e n s i o n headaches and  t h e r e l a t e d symptom o f i n s o m n i a , b u t t h e r e was no r e -  duction i n the subjects' reports of anxiety.  Other a t t e m p t s  t o reduce a n x i e t y by r e d u c i n g muscle t e n s i o n have a l s o been unsuccessful  ( G a r r e t t & S i l v e r , 1972; Wickramasekera, 1972).  S i m i l a r l y t h e r e was no r e a s o n t o b e l i e v e from E x p e r iment 2 t h a t t h e v a r i o u s muscle t e n s i o n l e v e l s assumed by the s u b j e c t s had an e f f e c t on t h e i r s u b j e c t i v e s t a t e .  Thus,  a p p a r e n t l y h i g h l e v e l s o f muscle t e n s i o n , even when they a r e not a s s o c i a t e d w i t h h i g h l e v e l s o f s u b j e c t i v e t e n s i o n , can d i s r u p t performance.  Therefore,  i n actual  competitive  s i t u a t i o n s such as t h a t i n Experiment 1, when b o t h muscle t e n s i o n and s u b j e c t i v e t e n s i o n a r e h i g h , t h e b i o f e e d b a c k t e c h n i q u e can a p p a r e n t l y be used t o reduce muscle t e n s i o n b u t n o t s u b j e c t i v e tension (Raskin e t a l . ,  1973)-  A l t h o u g h performance  57  might a l s o be improved b y r e d u c i n g s u b j e c t i v e t e n s i o n , t h i s i s c l e a r l y o u t o f the realm o f p r e s e n t i n v e s t i g a t i o n s . P h y s i o l o g i c a l Mechanisms Although  i t was n o t t h e purpose o f t h i s t h e s i s t o  e l a b o r a t e on t h e p h y s i o l o g i c a l b a s i s o f h i g h l e v e l s o f muscle t e n s i o n o r o f t h e i r d i s r u p t i v e e f f e c t s on performance, the p r e s e n t  f i n d i n g s can be p a r t i a l l y i n t e g r a t e d i n t o c u r r e n t  physiological theories. I t i s w e l l documented t h a t t h e p r e s e n c e o f p h y s i c a l o f p s y c h o l o g i c a l s t r e s s can cause a l t e r a t i o n s i n i n d i v i d u a l s ' s u b j e c t i v e s t a t e s as w e l l as i n d u c i n g a number o f p e r i p h e r a l r e s p o n s e s such as i n c r e a s e d h e a r t r a t e , e l e v a t e d b l o o d  pres-  s u r e , a c c e l e r a t e d b l o o d f l o w t o t h e t i s s u e s , and e l e v a t e d b l o o d g l u c o s e c o n c e n t r a t i o n s which a r e mediated by the r e lease of the catacholamines adrenergic  n o r a d r e n a l i n and a d r e n a l i n from  f i b e r s o f the sympathetic  the a d r e n a l medullae (Guyton, 1971).  nervous system and from This increase i n c i r -  c u l a t i n g n o r a d r e n a l i n and a d r e n a l i n may a l s o be r e s p o n s i b l e f o r t h e i n c r e a s e d muscle t e n s i o n l e v e l s a s s o c i a t e d w i t h subjective states of stress. H u t t e r and L o e w e n s t e i n (1955) i s o l a t e d the i l i o f i b u l a r i s muscle and i t s e f f e r e n t sympathetic  f i b e r s from  a f r o g and bathed t h e muscle i n R i n g e r s o l u t i o n .  A number  of t e s t s were conducted t o determine the e f f e c t o f s e l e c t e d c h e m i c a l a g e n t s on t h e c o n t r a c t i l e p r o p e r t i e s o f t h e muscle. They found a s i g n i f i c a n t i n c r e a s e i n the f r e q u e n c y  o f min-  58  i a t u r e end-plate p o t e n t i a l s occurred f o l l o w i n g a d d i t i o n of n o r a d r e n a l i n o r a d r e n a l i n to the R i n g e r s o l u t i o n "bathing the i s o l a t e d muscle.  Therefore,  the s y m p a t h e t i c a l l y mediated  r e l e a s e of n o r a d r e n a l i n and a d r e n a l i n i n response to s t r e s s f u l s i t u a t i o n s c o u l d be a f a c t o r i n the i n c r e a s e d muscle t e n s i o n commonly a s s o c i a t e d w i t h s t r e s s f u l The  situations.  d i s r u p t i v e e f f e c t s of muscle t e n s i o n on  the  performance of the motor s k i l l s  of Experiment 2 i s more  d i f f i c u l t to e x p l a i n .  i t i s tempting  Although  to i n t e r p r e t  the r e s u l t s i n terms of nervous or m u s c u l a r f a t i g u e , n e i t h e r e x p l a n a t i o n seems t o t a l l y s a t i s f a c t o r y . i n muscles ( A s t r a n d , 1970;  Demonstrable f a t i g u e  d e V r i e s , 1976)  which i n n e r v a t e them ( A s t r a n d , 1970;  or i n the neurons  Merton, 1954)  generally  r e q u i r e s much g r e a t e r c o n t r a c t i o n over l o n g e r p e r i o d s time than i n Experiment  of  2.  S t r a t e g i e s o f A p p l i e d Research The  two  experiments c o m p r i s i n g  the p r e s e n t t h e s i s  are b e s t viewed as the f i r s t step i n a much l a r g e r p r o j e c t designed  t o improve the performance of a t h l e t e s by u s i n g  biofeedback  techniques  muscle t e n s i o n .  to reduce p r e - c o m p e t i t i o n  l e v e l s of  Thus, i t i s a p p r o p r i a t e t o d i s c u s s the  r e l a t i o n s h i p of the p r e s e n t  s t u d i e s t o the u l t i m a t e g o a l  and the s t r a t e g i e s of f u t u r e r e s e a r c h which may of them.  EMG  grow out  I n so d o i n g i t i s advantageous to c o n t r a s t the  a p p l i e d approach used i n the p r e s e n t  s t u d i e s w i t h the more  59  t h e o r e t i c a l l y o r i e n t e d approach t h a t seems t o c h a r a c t e r i z e research  i n the area of p h y s i c a l  education.  I t i s i n t e r e s t i n g to note that, although the area of p h y s i c a l education  i s "by i t s v e r y n a t u r e a p p l i e d , t h e o r e t i c a l  r e s e a r c h h o l d s a more eminent p o s i t i o n t h a n a p p l i e d  research—  p r o b a b l y because o f t h e i n f l u e n c e o f r e l a t e d by more t h e o r e t i c a l l y - o r i e n t e d d i s c i p l i n e s such as p h y s i o l o g y  and p s y c h -  o l o g y — a n d i s t h e r e f o r e funded t o a g r e a t e r e x t e n t .  Because  applied research  i s o f t e n t e c h n i c a l l y complex y e t c o n c e p t u a l l y  unsophisticated,  t h e r e i s a tendency i n most a r e a s o f , t h e be-  h a v i o u r a l sciences t o concentrate  almost e x c l u s i v e l y on "pure"  research  conducted i n l a b o r a t o r y s e t t i n g s .  Research on the  question  o f EMG-behaviour r e l a t i o n s r e v i e w e d e a r l i e r i n  Chapter k e f f e c t i v e l y i l l u s t r a t e s the p o i n t that i t i s f r e q u e n t l y d i f f i c u l t t o a p p l y the r e s u l t s o f pure l a b o r a t o r y research  t o even t h e most b a s i c a p p l i e d i s s u e s .  Thus, t h e r e  i s c e r t a i n l y room i n an a p p l i e d d i s c i p l i n e such as p h y s i c a l education  f o r more a p p l i e d  Although previous  research. s e c t i o n s o f the p r e s e n t t h e s i s  have s t r e s s e d t h e importance o f r e s e a r c h  i n field  situa-  t i o n s , i n v e s t i g a t o r s w o r k i n g i n such s e t t i n g s f r e q u e n t l y e n c o u n t e r a v a r i e t y o f c o n t r o l problems w h i c h can be r e a d i l y c i r c u m v e n t e d i n t h e more c o n t r o l l e d c o n f i n e s o f t h e l a b oratory.  Thus, " f i e l d " r e s e a r c h  is. frequently unconvincing  because o f t h e l a c k o f e x p e r i m e n t a l  c o n t r o l , but the r e s u l t s  of c o n t r o l l e d l a b o r a t o r y s t u d i e s a r e f r e q u e n t l y to apply to " r e a l - l i f e "  situations.  difficult  The p r e s e n t s t u d i e s  60 i l l u s t r a t e how l a b o r a t o r y and f i e l d s t u d i e s can be e f f e c t i v e l y combined. I s i t worthwhile  embarking on a p r o j e c t d e s i g n e d t o  improve a t h l e t i c performance by r e d u c i n g muscle t e n s i o n l e v e l s ?  pre-competition  The f i r s t s t e p i n answering t h i s  q u e s t i o n was t o determine whether c o m p e t i t i v e a t h l e t e s do i n f a c t have e l e v a t e d muscle t e n s i o n l e v e l s p r i o r t o competition.  C l e a r l y t h e o n l y way o f a n s w e r i n g t h i s q u e s t i o n  was t o measure muscle t e n s i o n l e v e l s i n c o m p e t i t i v e a t h l e t e s p r i o r to a c t u a l competitive events.  Once i t was e s t a b l i s h e d  t h a t a t l e a s t some c o m p e t i t i v e a t h l e t e s have e l e v a t e d muscle t e n s i o n l e v e l s p r i o r t o c o m p e t i t i o n , the n e x t step was t o determine whether such i n c r e a s e s c o u l d d i s r u p t performance. Although  t h i s q u e s t i o n must a l s o be u l t i m a t e l y answered i n  actual competitive s i t u a t i o n s , i n i t i a l laboratory i n v e s t i g a t i o n i n t o the problem had two advantages. f o r e an e x p e r i m e n t e r  F i r s t l y , be-  s h o u l d even c o n s i d e r d i s r u p t i n g t h e  p r a c t i c e s e s s i o n s o f s e r i o u s c o m p e t i t i v e a t h l e t e s , he o r she s h o u l d have r e a s o n a b l e a i d the a t h l e t e .  evidence  t h a t the r e s e a r c h  Attempts t o p r e m a t u r e l y  will  apply research  i d e a s b e f o r e t h e y have been s u b s t a n t i a t e d tend t o reduce, the p o s s i b i l i t i e s o f g a i n i n g t h e c o o p e r a t i o n o f s u b j e c t s at a l a t e r date.  Secondly,  the q u e s t i o n o f the r e l a t i o n  between muscle t e n s i o n and performance i s b a s i c a l l y a p a r a m e t r i c problem which can be more e f f e c t i v e l y s t u d i e d , a t least i n i t i a l l y ,  i n a c o n t r o l l e d l a b o r a t o r y environment.  61  Now t h a t Experiment 2 and t h e p r e l i m i n a r y s t u d i e s on which i t was b a s e d have p r o v i d e d  some b a s i c i n f o r m a t i o n  concerning  the r e l a t i o n s h i p between muscle t e n s i o n and performance, i t w i l l be e a s i e r t o study t h i s r e l a t i o n i n a c t u a l a t h l e t i c environments. The  n e x t step i n t h i s p r o j e c t w i l l be t o study the  r e l a t i o n between muscle t e n s i o n and performance i n a c t u a l c o m p e t i t i v e a t h l e t e s , and i f t h e r e i s a r e l a t i o n , t o u l t i m a t e t r a i n these a t h l e t e s t o assume those l e v e l s o f EMG most c o n d u c i v e t o good performance.  Moving i n t o t h e " f i e l d "  w i t h t h i s r e s e a r c h w i l l i n v o l v e a d o p t i n g a new protocol.  activity  experimental  R a t h e r t h a n s t u d y i n g t h e means o f l a r g e groups  of s u b j e c t s , t h e r e s e a r c h w i l l c e n t r e around t h e a n a l y s i s of a few c o o p e r a t i v e a t h l e t e s .  The main c o n c e r n w i l l be  t o f i n d what l e v e l s o f EMG a c t i v i t y a r e most e f f e c t i v e f o r a p a r t i c u l a r a t h l e t e engaging i n a p a r t i c u l a r s p o r t .  At t h i s  n e x t stage group means w i l l be l a r g e l y i r r e l e v a n t . D u r i n g e a r l y phases o f t h i s f i n a l stage o f r e s e a r c h i t w i l l be i m p o r t a n t  t o s e l e c t s u b j e c t s which a r e c o o p e r a t i v e  and a r e competing i n s p o r t s c o n d u c i v e t o data  collection.  S k i l l s such as t a r g e t s h o o t i n g , b a s e b a l l p i t c h i n g , s h o t p u t t i n g , and b a s k e t b a l l f r e e - t h r o w  s h o o t i n g l e n d themselves  t o o b j e c t i v e i n v e s t i g a t i o n . The r e s u l t s o f t h e p r e s e n t exp e r i m e n t s suggest t h a t b e s t r e s u l t s w i l l be o b t a i n e d  with  s p o r t s i n v o l v i n g hand s t e a d i n e s s and upper body s t r e n g t h .  Chapter 6 SUMMARY AND EMG "biofeedback  CONCLUSIONS  has been used t o t r a i n s u b j e c t s t o  c o n t r o l t h e i r l e v e l s o f muscle t e n s i o n . ment o f t h i s t e c h n i q u e  The r e c e n t  develop-  r a i s e d t h e p o s s i b i l i t y t h a t compet-  i t i v e a t h l e t e s c o u l d enhance t h e i r performance by l e a r n i n g t o c o n t r o l t h e i r l e v e l s o f muscle t e n s i o n i n t h e p e r i o d ' p r i o r to competition.  Although  I t has been r e p o r t e d  that  the p r e s e n c e o f p s y c h o l o g i c a l o r p h y s i o l o g i c a l s t r e s s o r s c o u l d cause an i n c r e a s e i n muscle t e n s i o n l e v e l s , t h e r e was no e m p i r i c a l e v i d e n c e which demonstrated t h a t such i n c r e a s e s are e x p e r i e n c e d  by competitive a t h l e t e s p r i o r t o important  events. I n Experiment 1 t h e r e was a s i g n i f i c a n t i n c r e a s e i n the muscle t e n s i o n l e v e l s o f c o m p e t i t i v e w r e s t l e r s p r i o r t o an i m p o r t a n t match.  Experiment 2 was t h e n conducted t o de-  termine whether t h e i n c r e a s e s i n muscle t e n s i o n o f the magn i t u d e n o t e d i n Experiment 1 were s u f f i c i e n t t o d i s r u p t the performance o f s p o r t - r e l a t e d motor t a s k s .  The s u b j e c t s '  performance on a Hand-Steadiness, a C h o i c e Response-Time, and a G r i p - S t r e n g t h Task was a s s e s s e d  a f t e r low, medium, o r  h i g h t e n s i o n l e v e l s were assumed w i t h t h e a i d o f EMG b i o feedback.  H i g h a n t e c e d e n t l e v e l s o f muscle t e n s i o n s i g 62  63  n i f i c a n t l y d i s r u p t e d the performance o f "both the G r i p S t r e n g t h and the Hand-Steadiness T e s t s . Thus, the r e s u l t s of the p r e s e n t t h e s i s  justify  f u t u r e r e s e a r c h i n t o the use o f the EMG b i o f e e d b a c k r e l a x a t i o n t e c h n i q u e ; a t e c h n i q u e which w i l l h o p e f u l l y reduce c o m p e t i t i v e a t h l e t e s ' p r e - c o m p e t i t i o n muscle t e n s i o n l e v e l s , t h e r e b y i m p r o v i n g t h e i r a t h l e t i c performance.  REFERENCES A l e x a n d e r , B. An e x p e r i m e n t a l t e s t of assumptions r e l a t i n g the use o f e l e c t r o m y o g r a p h i c b i o f e e d b a c k as a g e n e r a l r e l a x a t i o n t e c h n i q u e . P s y c h o p h y s i o l o g y , 1975, 12 (6),  656-662.  ~  Andrews, J . Neuromuscular r e - e d u c a t i o n o f the h e m i p l e g i c w i t h the a i d of the e l e c t r o m y o g r a p h . A r c h i v e s of P h y s i o l o g y and M e d i c a l R e h a b i l i t a t i o n , 1964, 45, 530B a s m a j i a n , J . M u s c l e s A l i v e (3rd e d . ) . & W i l k i n s , 1974.  Baltimore:  Williams  B e l l , H. E f f e c t s o f e x p e r i m e n t a l l y - i n d u c e d muscular t e n s i o n and f r e q u e n c y o f m o t i v a t i o n a l i n s t r u c t i o n s on p u r s u i t r o t o r performance. P e r c e p t u a l and Motor S k i l l s , 1959i  9, 111-115.  :  ~  B l a n c h a r d , E,, & Young, L. C l i n i c a l a p p l i c a t i o n s o f b i o feedback t r a i n i n g : a r e v i e w of e v i d e n c e . A r c h i v e s o f G e n e r a l P s y c h i a t r y , 1974, 30, 573-589Broadbent, D., & Gregory, M. D i v i s i o n of a t t e n t i o n and the d e c i s i o n theory of s i g n a l d e t e c t i o n . Proceedings of the R o y a l S o c i e t y , 1963, 158, 222-231. Broadbent, D., & Gregory, M. On the i n t e r a c t i o n o f S-R c o m p a t i b i l i t y with other v a r i a b l e s a f f e c t i n g r e a c t i o n t i m e . B r i t i s h J o u r n a l o f P s y c h o l o g y , 1965, 56, 61-67. B u d z y n s k i , T., & S t o y v a , J . An i n s t r u m e n t f o r p r o d u c i n g deep r e l a x a t i o n by means o f a n a l o g i n f o r m a t i o n f e e d back. J o u r n a l of A p p l i e d B e h a v i o u r a l A n a l y s i s , 1969,  2, 231-237:  B u d z y n s k i , T., S t o y v a , J . , & A l d e r , C. Feedback-induced muscle r e l a x a t i o n : a p p l i c a t i o n t o t e n s i o n headache. J o u r n a l of B e h a v i o u r a l Therapy and E x p e r i m e n t a l P s y c h i a t r y , 1970, 1, 205-211. C o u r t s , F. The i n f l u e n c e of p r a c t i c e on the dynamogenic e f f e c t of muscular t e n s i o n . J o u r n a l o f E x p e r i m e n t a l P s y c h o l o g y , 1942, 29, 504-511": d e V r i e s , H. Brown,  P h y s i o l o g y o f E x e r c i s e (2nd e d . ) . 1976. 64  Dubuque:  65  D i C a r a , L. L e a r n i n g i n the autonomic nervous system. S c i e n t i f i c American, 1970, 221 ( l ) , 31-39. Finn, J.D. M u l t i v a r : U n i v a r i a t e and M u l t i v a r i a t e A n a l y s i s of V a r i a n c e . F a c u l t y of E d u c a t i o n a l S t u d i e s , State U n i v e r s i t y of New York a t B u f f a l o . 1972. Freeman, G. The f a c i l i t a t i v e and i n h i b i t o r y e f f e c t s of muscular t e n s i o n upon performance. American J o u r n a l of Psychology, 1933, 45' 17-52. Freeman, "G. The optimal muscular t e n s i o n s f o r v a r i o u s performances. American J o u r n a l of Psychology, 1938, 51, 1 4 6 - 1 5 0 . : ; G a r r e t t , B., & S i l v e r , M. The use of EMG and alpha b i o feedback to r e l i e v e t e s t a n x i e t y i n c o l l g g e s s t u d e n t s . Read before the American P s y c h o l o g i c a l A s s o c i a t i o n Meeting, Washington, DC, 1972. Guyton, A. Textbook of M e d i c a l P h y s i o l o g y Toronto: Saunders, 1971.  (4th e d . ) .  Hardyck, C , P e t r i n o v i c h , L., & E l l s w o r t h , D. Feedback of speech muscle a c t i v i t y d u r i n g s i l e n t reading: rapid extinction. Science, 1966, 154, 1467-1468. Haynes, S., Moseley, D., & McGowan, W. Relaxation t r a i n i n g and biofeedback i n the r e d u c t i o n of f r o n t a l i s muscle t e n s i o n . Psychophysiology, 1975, 12 ( 5 ) , 5 4 7 - 5 5 2 . Hutter, 0., & Loewenstein, W. Nature of neuromuscular f a c i l i t a t i o n by sympathetic s t i m u l a t i o n i n the f r o g . J o u r n a l of P h y s i o l o g y , 1955, 130, 559-571. Jacobson, E. P r o g r e s s i v e R e l a x a t i o n . of Chicago, 1938.  Chicago:  University  James, J . , & Horton, D. RMS and average measurements of EMG waveforms (1st ed.). Boston: Cyborg, 1976. Luthe, W. (Ed.). 'Autogenic Therapy (5 v o l s . ) . Grune & S t r a t t o n , 1 9 6 9 .  New  York:  M a r i n a c c i , A., & Horande, M. Electromyogram i n neuromuscular r e - e d u c a t i o n . B u l l e t i n of the Los Angeles N e u r o l o g i c a l S o c i e t y , I960, 2 5 , 57-71. Merton, P. V o l u n t a r y s t r e n g t h and f a t i g u e . P h y s i o l o g y , 1954, 123-,- 553-  Journal of  66 M i l l e r , N. L e a r n i n g o f v i s c e r a l and g l a n d u l a r r e s p o n s e s . S c i e n c e . 1 9 6 9 , l 6 j , 434-445. P a r k e r , N. I n f l u e n c e o f induced muscular t e n s i o n on a t i m e - e s t i m a t i o n motor t a s k . J o u r n a l o f Motor B e h a v i o u r .  1973, i (2), 111-120.  P i n n e o , L. The e f f e c t s o f i n d u c e d muscle t e n s i o n d u r i n g t r a c k i n g on l e v e l o f a c t i v a t i o n and on performance. J o u r n a l o f E x p e r i m e n t a l P s y c h o l o g y . 1 9 6 1 , .62, 523-531. R a s k i n , M., Johnson, G., & Rondestvedt, J . C h r o n i c a n x i e t y t r e a t e d by f e e d b a c k - i n d u c e d muscle r e l a x a t i o n : a p i l o t s t u d y . A r c h i v e s o f G e n e r a l P s y c h i a t r y , 1973, 28, 2 6 3 266.  R u s s e l l , J . R e l a t i v e e f f i c i e n c y o f r e l a x a t i o n and t e n s i o n i n p e r f o r m i n g an a c t o f s k i l l . J o u r n a l of General P s y c h o l o g y , 1932, 6, 330-3^3S e l y e , H. S t r e s s Without D i s t r e s s . L i p p i n c o t t , 1974. S m i t h , B. (1),  The p o l y g r a p h . 25-31.  New York:  S c i e n t i f i c American, :  J.B. 1 9 6 7 , 216  "  Smith, L. E f f e c t o f muscular s t r e t c h , t e n s i o n , and r e l a x a t i o n upon t h e r e a c t i o n time and speed o f movement o f a supp o r t e d l i m b . The Research Q u a r t e r l y . 1964, 35 (4), 546-  553.  S t a u f f a c h e r , J . The e f f e c t o f induced muscular t e n s i o n upon v a r i o u s phases o f the l e a r n i n g p r o c e s s . J o u r n a l o f E x p e r i m e n t a l P s y c h o l o g y , 1937, 21, 26-46. Thompson, R., L i n d s l e y , D., & Eason, R. E x p e r i m e n t a l Methods and I n s t r u m e n t a t i o n i n P s y c h o l o g y (1st e d . ) . New York: M c G r a w - H i l l , 1 9 6 6 . Wickramasekera, I . I n s t r u c t i o n s and EMG feedback i n s y s t e m a t i c d e s e n s i t i z a t i o n : a case r e p o r t . B e h a v i o u r a l Therapy, 1 9 7 2 , ^ , 4 6 0 - 4 6 5 . Wolpe, J . P s y c h o t h e r a p y by R e c i p r o c a l I n h i b i t i o n . S t a n f o r d : S t a n f o r d U n i v e r s i t y P r e s s , 1958. Z aichowsky, L. Combating s t r e s s : what about r e l a x a t i o n t r a i n i n g and b i o f e e d b a c k ? Mouvement, 1975, £, 3 0 9 - 3 1 2 .  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0077115/manifest

Comment

Related Items