College of Physical Education and Sports, Beijing Normal University, Beijing, China.
College of Physical Education and Sports, Beijing Normal University, Beijing, China.
Knee. 2024 Jun;48:207-216. doi: 10.1016/j.knee.2024.04.004. Epub 2024 May 10.
Most studies on cutting have focused on the biomechanics of the knee and lower-limb muscle activation characteristics, with less consideration given to the influence of motor experience on control strategies at the joint level. This study aimed to investigate the differences in knee stability and inter-joint coordination between high- and low-level athletes when cutting at different angles.
A Vicon motion capture system and a Kistler force table were used to obtain kinematic and ground reaction force data during cutting. Joint dynamic stiffness and vector coding were used to assess knee stability and inter-joint coordination. Uncontrolled manifold analysis was used to clarify whether there was synergy among lower-limb joints to maintain postural stability during cutting.
During the load acceptance phase, skilled subjects had the smallest joint stiffness at 90° compared with novice subjects (P < 0.05). Compared with novice subjects, skilled subjects had smaller knee-hip ellipse areas at 90° and 135° (P < 0.05), but larger knee-ankle ellipse areas at 135° (P < 0.05). The synergy index in load acceptance was significantly higher (P < 0.05) for skilled subjects at 90° and 135°.
Advanced subjects can adjust joint control strategies to adapt to the demands of large-angle cutting on the change of direction. Advanced subjects can reduce knee stability for greater flexibility during cutting compared with novice subjects. By increasing the degree of synergy among the lower-limb joints, advanced athletes can maintain high postural stability.
大多数关于变向切割的研究都集中在膝关节的生物力学和下肢肌肉激活特性上，而对运动经验对关节水平控制策略的影响关注较少。本研究旨在探讨高水平和低水平运动员在不同角度变向切割时膝关节稳定性和关节间协调性的差异。
使用 Vicon 运动捕捉系统和 Kistler 力台获取变向切割过程中的运动学和地面反作用力数据。采用关节动态刚度和向量编码评估膝关节稳定性和关节间协调性。采用非受控制流形分析来阐明下肢关节在变向切割过程中是否存在协同作用以维持姿势稳定性。
在承受负荷阶段，与新手相比，熟练组在 90°时的关节刚度最小（P<0.05）。与新手相比，熟练组在 90°和 135°时膝关节-髋关节椭圆面积较小（P<0.05），但在 135°时膝关节-踝关节椭圆面积较大（P<0.05）。在承受负荷阶段，熟练组的协同指数在 90°和 135°时显著更高（P<0.05）。
高级运动员可以调整关节控制策略，以适应大角度变向对方向变化的要求。与新手相比，高级运动员在变向切割时可以降低膝关节稳定性，以提高灵活性。通过增加下肢关节之间的协同程度，高级运动员可以保持较高的姿势稳定性。
