Acute Change of Footwear Limits Performance and Alters Foot Strike Patterns During Anticipated and Unanticipated 90° Change of Direction.

BACKGROUND: Footwear influences performance and injury risk during change-of-direction (COD) movements. However, few studies have investigated how different shoe types influence COD biomechanics, particularly under ecologically valid conditions such as at sharp angles and under unanticipated conditions. This study examined the impact of barefoot, minimalist, and standard sport shoes on biomechanical and performance parameters during 90° COD tasks. METHODS: Forty-one participants (14 females and 27 males) completed a randomized crossover study, performing anticipated and unanticipated 90° COD tasks under three footwear conditions: barefoot, minimalist shoes, and habitual standard sport shoes. Kinematic, kinetic, and lower leg muscle activity data were collected using motion capture, force plates, and surface electromyography. RESULTS: Standard sport shoes resulted in faster COD completion times, significantly higher approach velocity, and greater braking and propulsion forces than minimalist and barefoot condition (p < 0.05). Minimalist and barefoot condition led to altered foot strike patterns, reduced knee flexion, and lower GRF magnitudes. Unanticipated trials increased neuromuscular demand, reducing approach velocity and altering GRF distribution across all footwear conditions. After controlling for approach velocity, footwear effects remained significant in most kinetic and kinematic measures. CONCLUSION: These findings highlight the importance of footwear choice for performance and biomechanical outcomes during challenging COD tasks.