Muscle strength in the lower extremity does not predict postinstruction improvements in the landing patterns of female athletes.

摘要

STUDY DESIGN: Preinstruction and postinstruction testing in a laboratory setting. OBJECTIVES: To examine the predictive relationship between lower extremity muscle strength and the immediate postinstruction changes in landing patterns of female athletes. We hypothesized that greater strength would be associated with larger postinstruction improvements in landing patterns. BACKGROUND: Female athletes in high-demand sports may be predisposed to anterior cruciate ligament injury because of poor landing patterns. Instruction has been shown to improve landing patterns. Lower extremity muscular strength may determine the potential for instruction to alter landing patterns. METHODS AND MEASURES: Thirty-seven female collegiate athletes in high-demand sports participated. Strength was assessed in the following muscle groups: trunk extensors and flexors, hip abductors and extensors, knee flexors and extensors, and ankle plantar flexors. Strength testing was followed by kinetic and kinematic analysis of a drop vertical jump task. Athletes then received verbal instruction on how to improve their landing technique and were retested. Landing variables of interest were force absorption time, peak vertical ground reaction force (vGRF), peak knee flexion and abduction angle, and peak external knee abduction moment. Preinstruction and postinstruction landing variables data were compared. Linear regression models were created with strength values as independent variables and landing variables as dependent variables. RESULTS: After instruction, athletes significantly increased their force absorption time and peak knee flexion angle, while decreasing their peak vGRF, peak knee abduction angle, and peak external knee abduction moment (P<.001). None of the regression models were statistically significant (P>.05). CONCLUSIONS: A brief instructional session promotes short-term improvements in the landing patterns of collegiate female athletes, but muscular strength was a poor predictor of the improvements.