The Biomechanical Effects of Fatigue on Drop-Jump Performance in Basketball Athletes

Abstract

Anterior Cruciate Ligament (ACL) injuries have high occurrences in the sport of basketball due to the high amounts of landing, cutting, and other sudden deceleration maneuvers. During landing, studies have prospectively linked insufficient amounts of knee flexion, greater knee valgus angles, and greater knee valgus moments accompanied by greater vertical ground reaction force to increased risk of ACL injuries. These mechanisms have shown to be increased in a fatigued state therefore suggesting an athlete may be at greater risk for ACL injury when they are fatigued. Research to support this claim, however, is inconclusive. PURPOSE: To examine the difference in peak knee flexion angle (pKFA), peak knee valgus angle (pKVA), peak knee valgus moment (pKVM), and peak vertical ground reaction force (vGRF) pre and post fatigue during the landing phase of a drop jump task in basketball athletes. METHODS: Twenty-five subjects participated in the study and performed three drop jump trials before and after a fatigue protocol involving repeated counter movement jumps touching a customized target specific to each subject. Data was captured using a Qualisys 9-camera motion capture system sampling at 240-Hz and two AMTI force plates sampling at 2400-Hz. RESULTS: Paired t-tests showed subjects landed with significantly greater pKFA post fatigue (p < .05) while pKVA, pKVM, and pGRF showed no difference pre- and post-fatigue (p > .05). CONCLUSION: Subjects in this study adopted a safer landing strategy post fatigue, hence, suggesting our study did not support the claim that athletes would be at greater risk for ACL injuries in a fatigued state.