## 4 Discussion
Concurrently, the shorter T_vGRF observed in individuals with FAI compared to the healthy population indicates a quicker attainment of peak vGRF upon landing, which may be a mechanism they adopt to rapidly stabilize body posture and reduce ankle joint loading. Additionally, the lack of significant differences in the peak vGRF, LR, and k\({}_{\text{leg}}\) indicators in this study's results also supports the above discussion, indicating the unique adaptability of individuals with FAI in their landing strategies, relying more on the knee flexion angle to maintain the overall lower-limb mechanical performance stability [28]. This result highlights that in rehabilitation training, in addition to focusing on the movement strategies of the ankle and knee joints, consideration should also be given to how to improve the overall lower-limb mechanical performance of individuals with FAI through training, thereby enhancing their sports efficiency and reducing the risk of injury. However, it is noteworthy that under barefoot conditions, there was no significant difference in the ankle-joint plantar flexion angle between individuals with FAI and the healthy population. This finding suggests that despite the compromised stability of the ankle joint in individuals with FAI, they can still exhibit biomechanical characteristics similar to those of the healthy population in barefoot conditions. This may imply that barefoot activity provides a more natural environment for individuals with FAI, aiding in the re-establishment of the proprioceptive system around the ankle joint, thereby improving posture control and coordination. However, due to previous injuries, individuals with FAI may have reduced proprioception and neuromuscular control of the ankle joint, which could affect their performance in movements without external support [29; 25]. This is consistent with [PERSON] et al. [17], who suggested that individuals with CAI might derive significant biomechanical benefits from wearing shoes, reducing the ankle-joint plantar flexion angle and providing additional support and stability. [PERSON] et al. [30] further confirmed through experimentation that moderate ankle joint support can promote the utilization of the knee and hip joints to share the load during single-leg drop landing movements, thereby optimizing muscle coordination and joint control. Therefore, for individuals with FAI, wearing appropriate footwear during tasks such as landing may enhance foot stability and provide necessary support, enabling more precise neuromuscular feedback and adjustment during movement, optimizing movement mechanics, and reducing the risk of injury. Thus, footwear conditions play a crucial role in the movement process of individuals with FAI. Wearing shoes may assist individuals with FAI in more easily controlling the motion of the ankle joint, while barefoot conditions may help them approximate the biomechanical characteristics of the healthy population in certain aspects, especially in training for proprioception and balance capabilities. As [PERSON] et al. [31] demonstrated, footwear conditions are an undeniable factor when assessing ankle-foot kinematics and dynamics. This emphasizes the need to consider the impact of footwear conditions comprehensively and to customize treatment plans according to the individual circumstances and needs of individuals with FAI.