Abstract
This study aimed to compare the knee and ankle joint load characteristics of high and low Tai Chi postures, focusing on three typical Tai Chi movements: Wild Horse Mane (WHM), Repulse Monkey (RM), and Wave Hand in Cloud (WHC). It further explored how different postures affect lower limb loading in practitioners with varying skill levels to provide optimal guidance for Tai Chi practice. A total of 26 male participants were enrolled, divided into the professional group (PG, n = 13) and the interest group (IG, n = 15). A three-dimensional (3D) high-speed motion capture system was employed to record participants' Tai Chi movements, while a force platform was used concurrently to collect kinematic and dynamic data. For the knee joint, both groups exhibited significantly higher peak moments in the sagittal and coronal planes during the low posture than the high posture across all three movements (p < 0.05). During WHM, significant differences in peak ankle moments (sagittal and coronal planes) were noted between the two groups. In RM, the IG showed significantly higher peak ankle moments (sagittal and coronal planes) than the PG (p < 0.05). A significant positive correlation was found between posture/skill level and lower limb joint loading, with the knee joint being most affected. Professional practitioners should strengthen the muscles surrounding the knee and ankle joints to enhance joint protection during high-intensity practice and prevent chronic sports injuries resulting from long-term joint fatigue. For amateurs, a gradual transition from high to low postures is recommended to adapt to and enhance joint load-bearing capacity. Additionally, beginners should prioritize ankle flexibility training to improve ankle stability and lower injury risk.