Quantification and Modeling of Ankle Stiffness During Standing Balance
Quantification and Modeling of Ankle Stiffness During Standing Balance
复制标题
站立平衡过程中踝关节刚度的量化和建模
DOI：
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发表时间：
2020
影响因子：
4.6
通讯作者：
Hyunglae Lee
中科院分区：
文献类型：
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作者：
Varun Nalam;Ermyntrude Adjei;Hyunglae Lee
目的：探讨站立平衡时踝关节刚度调节的影响因素，并评价线性刚度模型的可靠性。方法：采用双轴机器人平台和视觉反馈显示器，在受试者控制不同程度的踝关节肌肉共收缩、压力中心（CoP）和踝关节负荷的同时，量化矢状面和额平面的踝关节刚度。结果：40例受试者的结果显示，踝关节矢状面僵硬度随这三个因素水平的增加而线性增加。将这些因素的变化从安静站立时的基线测量值与体重标准化踝关节刚度的变化联系起来的线性模型具有很高的可靠性（R2 = 0.83）。踝关节前平面刚度随踝关节肌肉共收缩和踝关节负荷的增加而增加，但线性关系不明显。当CoP向中侧向移动时，也表现出明显的非线性趋势。因此，线性模型对踝关节前平面刚度的可靠性较低（R2 = 0.37）。结论：在站立平衡过程中，如果综合考虑踝关节肌肉激活、CoP和踝关节负荷，踝关节矢状面僵硬可以用线性模型很好地解释。然而，线性模型不能捕捉高度可变和非线性的踝关节前平面刚度特征。意义：本研究结果可为下肢机器人及其控制器的发展提供参考。此外，踝关节刚度模型可以作为制定患者特定踝关节康复方案的基线。
Objective: This study investigates the factors contributing to the modulation of ankle stiffness during standing balance and evaluates the reliability of linear stiffness models. Methods: A dual-axis robotic platform and a visual feedback display were used to quantify ankle stiffness in both the sagittal and frontal planes while subjects controlled different levels of ankle muscle co-contraction, center-of-pressure (CoP), and loading on the ankle. Results: Results of 40 subjects demonstrated that ankle stiffness in the sagittal plane linearly increased with the increasing level of these three factors. The linear model relating the change in these factors from the baseline measurements during quiet standing to the change in weight normalized ankle stiffness resulted in high reliability (R2 = 0.83). Ankle stiffness in the frontal plane increased with the increasing ankle muscle co-contraction and ankle loading, but the linearity was less obvious. It also exhibited a clear nonlinear trend when CoP was shifted mediolaterally. Consequently, the reliability of the linear model was low for ankle stiffness in the frontal plane (R2 = 0.37). Conclusion: During standing balance, ankle stiffness in the sagittal plane could be well explained by a linear model if ankle muscle activation, CoP, and ankle loading were collectively considered. However, the linear model cannot capture highly variable and nonlinear ankle stiffness characteristics in the frontal plane. Significance: The outcomes of this study could benefit the development of lower-extremity robots and their controllers. Furthermore, the ankle stiffness models could be used as a baseline in developing patient-specific ankle rehabilitation protocols.
影响因子：
1.4
作者：
Buchanan, TS;Lloyd, DG;Besier, TF
通讯作者：
Besier, TF
影响因子：
2.4
作者：
Sartori, Massimo;Farina, Dario;Lloyd, David G.
通讯作者：
Lloyd, David G.