Impact of exercise-induced fatigue on the risk of stress fractures in the tibia during smash landing in female badminton players.

This study aimed to investigate the effects of exercise-induced fatigue on the risk of tibial stress fractures by comparing biomechanical parameters during backhand-side smash landings in elite female badminton players before and after fatigue. Thirteen elite female badminton players performed smash-landing trials before and after fatigue. The AnyBody Modeling System was used for inverse dynamics analysis, and finite element analysis was conducted using the AnyFE2Abq plugin to compute tibial stress and strain. After fatigue, the backhand rearcourt jump smash (BRJS) and the backhand lateral jump smash (BLJS) landing movements showed significantly increased peak tibial acceleration (p = 0.003; p = 0.008), vertical average loading rate (p = 0.024; p = 0.040), and vertical instantaneous loading rate (p = 0.007; p = 0.029. Moreover, the simulated tibialis anterior muscle force significantly decreased after fatigue (p = 0.004; p = 0.046). Finite element analysis further revealed markedly increased tibial stress and strain after fatigue, with peak stress and strain reaching multiple times the pre-fatigue values (peak stress: BRJS anterior medial, 224.0%; BRJS posterior, 213.2%; BLJS anterior medial, 348.6%; BLJS posterior, 522.8%; peak strain: BRJS, 241.1%; BLJS, 243.7%). Exercise-induced fatigue increased tibial acceleration and vertical loading rates during smash landings in elite female badminton players. Tibial stress and strain also increased, suggesting a potentially higher risk of tibial stress fracture.