Terada Masafumi, Morgan Kristin D, Gribble Phillip A
College of Sport and Health Science, Ritsumeikan University, Integration Core Building 602, 1-1-1 Noji-higashi, Kusatsu, Shiga 525-8577, Japan.
Department of Biomedical Engineering, University of Connecticut, A.B. Bronwell Building, Room 307, 260 Glenbrook Road, Unit 3247, Storrs, CT 06269-3247, USA.
Clin Biomech (Bristol). 2019 Oct;69:39-43. doi: 10.1016/j.clinbiomech.2019.06.020. Epub 2019 Jun 29.
The aim of the current study was to assess movement strategies during a single leg balance in chronic ankle instability individuals with unstable postural control strategy identified by Nyquist and Bode analyses in conjunction with sample entropy.
Thirty-three participants with self-reported chronic ankle instability and 22 healthy controls performed single-leg eyes closed static balance trials. The sagittal and frontal plane kinematics in the lower extremity and trunk as well as center of pressure trajectories were recorded during three, 20-second trials. The Nyquist and Bode stability analyses, which classify center of pressure waveforms as stable based on the resulting gain and phase margins, were performed to identify the presence of postural control deficits. Sample entropy was implemented to analyze movement strategies during the task.
Based on the Nyquist and Bode stability analyses, we included 19 out of 33 chronic ankle instability participants with unstable postural control strategy and 16 out of 22 controls with stable postural control strategy in the final analyses. Chronic ankle instability participants demonstrated a significantly lower sample entropy value in sagittal and frontal plane trunk kinematics and sagittal plane hip kinematics compared to the controls. No between-group differences existed in other kinematic measures.
The lower sample entropy values in participants with chronic ankle instability indicates that those with postural control deficits may increase reliance on the trunk and hip joint contributions to the maintenance of postural control, reflecting changes in the sensorimotor constraints on movement patterns during the task.
本研究旨在评估慢性踝关节不稳个体在单腿平衡时的运动策略，这些个体通过奈奎斯特和伯德分析结合样本熵确定存在不稳定的姿势控制策略。
33名自我报告有慢性踝关节不稳的参与者和22名健康对照者进行了单腿闭眼静态平衡试验。在三次20秒的试验中记录下肢和躯干在矢状面和额状面的运动学以及压力中心轨迹。进行奈奎斯特和伯德稳定性分析，根据所得增益和相位裕度将压力中心波形分类为稳定，以确定姿势控制缺陷的存在。采用样本熵分析任务期间的运动策略。
基于奈奎斯特和伯德稳定性分析，最终分析纳入了33名慢性踝关节不稳参与者中19名姿势控制策略不稳定的参与者以及22名对照者中16名姿势控制策略稳定的参与者。与对照组相比，慢性踝关节不稳参与者在矢状面和额状面躯干运动学以及矢状面髋关节运动学方面的样本熵值显著更低。其他运动学指标在组间无差异。
慢性踝关节不稳参与者较低的样本熵值表明，存在姿势控制缺陷的个体可能增加对躯干和髋关节在维持姿势控制方面贡献的依赖，反映了任务期间对运动模式的感觉运动约束的变化。
