Torque Production of the Dorsiflexors During Lengthening Contractions at Different Velocities in Young and Old

................................................................................................................................... ii ACKNOWLEDGEMENTS ........................................................................................................... iii TABLE OF CONTENTS ............................................................................................................... iv LIST OF ABBREVIATIONS ........................................................................................................ vi LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii LIST OF APPENDICES ................................................................................................................ ix CHAPTER 1: INTRODUCTION ................................................................................................... 1 1.1 BACKGROUND MUSCLE PHYSIOLOGY ....................................................................... 1 1.2 TIBIALIS ANTERIOR ......................................................................................................... 2 1.2.1 Anatomy and Function of the Tibialis Anterior ............................................................. 2 1.2.2 Muscle Model of Choice ................................................................................................ 2 1.3 AGE RELATED CHANGES................................................................................................ 3 1.3.1 Motor Neuronal Death .................................................................................................... 3 1.3.2 Change in Motor Unit Structure and Function ............................................................... 4 1.3.3 Passive Elements ............................................................................................................ 4 1.4 LENGTHENING VELOCITY ............................................................................................. 5 CHAPTER 2: METHODS .............................................................................................................. 7 2.1 PARTICIPANTS ................................................................................................................... 7 2.2 EXPERIMENTAL SETUP ................................................................................................... 7 2.3 RECORDING........................................................................................................................ 9 2.4 BASELINE MEASUREMENTS .......................................................................................... 9 2.5 LENGTHENING VELOCITIES ........................................................................................ 13 2.6 Data and Statistical Analysis ........................................................................................... 13 CHAPTER 3: RESULTS .............................................................................................................. 17