QUANTIFICATION OF LOWER EXTREMITY DYNAMIC CAPABILITY: IMPLICATIONS FOR ANTERIOR CRUCIATE LIGAMENT INJURY AND CHANGE OF DIRECTION ABILITY by

..................................................................................................................... xii CHAPTER I: OVERVIEW..................................................................................................1 CHAPTER II: BACKGROUND AND SIGNIFICANCE ...................................................3 I. Statement of the problem ...................................................................................... 3 II. Current understanding of ACL injury ................................................................... 4 Sex differences in kinematics, kinetics, and electromyography ........................ 5 Sagittal plane kinematics and kinetics .................................................... 5 Frontal plane kinematics and kinetics .................................................... 8 Muscle Activation.................................................................................... 9 III. Potential causes of higher ACL injury rates in females ..................................... 11 Influence of muscle strength on movement behavior ...................................... 12 Influence of sensorimotor control on movement behavior ............................ 15 How is sensorimotor control related to lower extremity injury risk? ............. 18 IV. Lower extremity dexterity as a novel theoretical construct ............................... 20 V. Quantifying lower extremity dexterity ............................................................... 22 VI. Summary ............................................................................................................ 23 CHAPTER III: THE LOWER EXTREMITY DEXTERITY TEST AS A MEASURE OF LOWER EXTRMEITY DYNAMICAL CAPABILITY .............................................26 Introduction .............................................................................................................. 27 Methods .................................................................................................................... 28 Subjects ........................................................................................................... 28 Procedures ...................................................................................................... 29 Statistical Analysis .......................................................................................... 34 Results ...................................................................................................................... 35