Collections > Electronic Theses and Dissertations > The Effect of Instructions on Lower Extremity Biomechanics and Performance Measures

The type of instructions given during completion of an anterior cruciate ligament injury prevention program may influence its effect on injury prevention and performance benefits. Research has yet to identify the impact of different instructions on injury prevention variables - knee abduction angle, knee flexion angle, hip adduction angle, vertical ground reaction force - and performance variables - vertical jump height and stance time. A crossover research design was used. Participants received injury prevention and performance based instructions in counterbalanced order. Separate paired T-test's were performed between change scores for each condition to determine the effect of different instructions on the dependent variables. A significant decrease in magnitude of hip adduction was found at initial contact when given injury prevention instructions and a significant decrease in magnitude of stance time resulted when given performance enhancement instructions during both landing tasks. A significant increase in magnitude of jump height resulted when given performance enhancement instructions.