This study examines the impact of support leg kinematics on kicking performance and its direct relationship with ball velocity and spin. Seventy-eight players performed maximal instep kicks each with their preferred and non-preferred leg, which were recorded with a three-dimensional motion capture system. Linear mixed models were used to analyze the effects of discrete data of lower limb on ball velocity and spin. Professional male players exhibited significantly smaller hip internal-external rotation range of motion (ROM) and angular velocity compared to other groups (p < 0.05). In professional players, the preferred leg kicks showed greater knee flexion-extension ROM, flexion angular velocity, and extension angular velocity than the non-preferred leg kicks (p < 0.01). Regression analysis revealed that hip and knee extension angular velocities, as well as knee flexion-extension ROM, positively influenced kicking performance, while hip adduction-abduction ROM had a negative impact. These findings emphasize the critical role of the support leg in modulating ball velocity, ball spin, and stability during instep kicking. Training should prioritize hip and knee extension strength for power generation and frontal plane stability for postural control. This study offers novel insights into support leg kinematics across competitive levels, with implications for coaching and performance enhancement. Future research should explore phase-specific support leg dynamics during kicking.

This study aimed to investigate the differences in proprioceptive changes at different time points (Pre vs. Post vs. 90 min vs. 24 h) before and after ischemic preconditioning. It followed a within-subject, self-controlled design, and a total of 21 trained male participants were assessed using two-point discrimination threshold tests on thigh and knee joint position sense testing. The results demonstrated that ischemic preconditioning effectively improved proprioceptive accuracy (two-point discrimination, right lower limb, p < 0.001; two-point discrimination, left lower limb, p < 0.001; knee position sense, right lower limb, p = 0.001; knee position sense, left lower limb, p = 0.014) and stability (two-point discrimination, right lower limb, p < 0.001; two-point discrimination, left lower limb, p = 0.002; knee position sense, right lower limb, p < 0.001; knee position sense, left lower limb, p = 0.003), with the optimal time point for enhancement identified at 90 min. This research suggests administering IPC 90 min before warm-up or competition to enhance athletic performance.