Foot-strike angle affects performance and injury risk during cutting in soccer athletes

Female soccer athletes experience elevated rates of non-contact anterior cruciate ligament injuries, particularly during cutting tasks that require rapid energy absorption and generation at the knee. This study examined the effects of sex and fatigue on knee joint power and foot‑strike angle during unanticipated cutting in cleated footwear. Twenty athletes (10 M/10F) completed unanticipated cuts before and after a standardized fatigue protocol. Kinematic and kinetic data were collected, and knee joint power and foot‑strike angle were calculated using standard inverse dynamics. Neither sex nor fatigue significantly influenced peak positive knee joint power (p > 0.05), although greater power was associated with faster approach velocities (p = 0.040). In contrast, peak negative knee joint power was greater in females, indicating a greater rate of energy absorption at the knee (p = 0.027). Foot‑strike angle differed by sex (p = 0.026), with females demonstrating greater angles at initial contact. A moderate negative correlation was observed between foot‑strike angle and peak negative knee joint power (r = -0.64, p = 0.005). These findings suggest that sex-related differences in cutting strategy may influence how energy is absorbed at the knee, with foot‑strike emerging as a potential contributor to these mechanical patterns.