Anticipatory and Reactionary EMG and Knee Joint Kinematics Between Male and Female Athletes during Single-Leg Landing Tasks: Relevance to Non-Contact ACL Injuries

Abstract

Background: Females are more likely to suffer anterior cruciate ligament (ACL) injuries. Muscle activity may be responsible in preventing ACL tears during jump-landings. Purpose: To determine a) whether sex differences exist in knee joint motion and muscle activity during preparatory and landing phases of single leg drop-jumps (SLJ) and b) whether an association between preparatory muscle activity and sex and landing knee joint motion exist. Methods: 33 male and 21 female athletes were recruited. Standardized biomechanical and electromyography procedures were used to record joint motion and muscle activity during the SLJ. Results: No sex differences in knee motion and muscle activity were found in preparatory and landing phases (p>0.05). Sex was not associated with knee motion in landing phases (p>0.05). Preparatory rectus femoris and medial hamstring muscle activity was associated with knee motion during landing phases (p<0.05). Conclusion: SLJ mechanics do not explain female injury risk in this athletic population.