Sex-specific biomechanical profiles in recreational alpine skiing: an integrated analysis of kinematics, muscle activation, and plantar pressure

While epidemiological data highlight higher knee injury rates among female alpine skiers compared to male skiers, particularly anterior cruciate ligament ruptures, biomechanical risk factors remain underexplored. This study investigates sex-specific biomechanical differences in recreational skiers to clarify potential disparities in movement strategies between sexes. Sixteen recreational skiers (nine females, seven males) performed standardized skiing tasks while joint kinematics, muscle activation, and foot forces were measured bilaterally using inertial sensors, surface electromyography, and pressure insoles, and analyzed separately for the inside and outside leg. Results showed distinct movement strategies between sexes. Males exhibited a "hip-dominated" steering strategy, with greater bilateral knee and ankle flexion (p < 0.001, d = 0.65 and 0.72, respectively), outside hip internal rotation (p < 0.001, d = 1.21), and bilateral biceps femoris activation (p < 0.001, d = 0.72-0.78). Conversely, females relied on a "knee-dominated" strategy, exhibiting increased valgus at the outside knee (p < 0.001, d = 1.18), greater rectus femoris activation in the inside leg (p = 0.005, d = 0.52), and higher forefoot plantar pressure on the outside limb (p < 0.001, d = 0.64). These sex-specific movement strategies may inform future prospective research on biomechanical risk factors for knee injuries in recreational alpine skiers. The results highlight the potential value of sex-specific training programs emphasizing balanced muscle co-activation and of equipment design considerations tailored to female-specific movement strategies.