The immediate effect of arch support insoles on the biomechanics of the lower limbs during the forward lunge step in badminton.

Background: The lunge step in badminton involves frequent impacts that contribute to lower-limb injuries. Although arch support insoles (ASI) are widely used for sports protection, studies on their application in badminton are limited, and internal loading during the lunge maneuver has rarely been examined. This study aimed to investigate the immediate effects of functional arch support insoles on lower-limb biomechanics and patellofemoral joint loading during a forward lunge in badminton. Methods: Sixteen students from a badminton class at the University of Physical Education performed a forward lunge using both original and arch support insoles. Kinematic and kinetic data were collected using a motion capture system and a force platform, while patellofemoral joint loading was estimated Results: Compared with the original insole, the arch support insole results in a smaller knee external rotation angle ( Conclusion: The results indicate that ASI altered ankle cushioning strategies, producing lower vertical ground reaction force loading rates. Furthermore, changes in hip and knee metrics suggest a potential reduction in dynamic knee valgus patterns. These results suggest that ASI may be able to reduce injury risk in badminton. However, ASI may also increase patellofemoral joint loading due to greater knee extension moments. Thus, balancing injury prevention and potential risks is crucial. Future research should investigate individualized fit strategies and the long-term biomechanical effects of ASI.