COMPARATIVE STUDY OF GROUND REACTION FORCES AND MUSCLE ACTIVATION SEQUENCES DURING JUMP-LANDING TASKS IN FEMALE VOLLEYBALL PLAYERS WITH AND WITHOUT ANTERIOR CRUCIATE LIGAMENT HISTORY

This study investigates differences in ground reaction forces (GRFs) and muscle activation sequences during jump-landing tasks in female volleyball players with and without a history of anterior cruciate ligament (ACL) reconstruction. Twenty-four athletes were divided into two groups: twelve with prior ACL reconstruction and twelve matched controls. Participants performed standardized drop vertical jumps while GRFs were recorded via force plates and muscle activation patterns were measured using surface electromyography (sEMG) of the quadriceps, hamstrings, and gastrocnemius. Results revealed that the ACL-reconstructed group exhibited significantly higher peak vertical GRFs and delayed hamstring activation compared to controls, suggesting reduced neuromuscular control and increased knee joint loading. These findings underscore the need for targeted neuromuscular training in post-rehabilitation programs to mitigate the risk of re-injury and enhance safe return to sport in female athletes.