Individual differences in intrinsic ankle stiffness and their relationship to body sway and ankle torque.
Individual differences in intrinsic ankle stiffness and their relationship to body sway and ankle torque.
复制标题
DOI：
10.1371/journal.pone.0244993
复制
发表时间：
2021
期刊：
影响因子：
3.7
通讯作者：
Reynolds RF
中科院分区：
文献类型：
--
作者：
Sakanaka TE;Lakie M;Reynolds RF
站立时，当使用大扰动测量时，当摇摆尺寸较大时，以及当背景力矩较小时，脚踝固有刚度较小。然而，个体固有的踝关节僵硬有很大的差异。在这里，我们确定个体差异是否对姿势控制有影响。我们研究了不同个体之间的踝关节僵硬、踝关节扭矩和身体摆动之间的关系。19名站立受试者通过测量扭矩对小的、短暂的扰动的反应来评估脚踝僵硬。0.2和0.9度的扰动大小(都持续140毫秒)分别测量短期和长期僵硬，而参与者要么安静地站在固定平台上，要么被潜意识地倾斜以降低稳定性(0.1赫兹正弦；0.2和0.4度)。自发性身体摇摆分量(自然随机相对快速的姿势调整)和背景踝关节扭矩是从扰动之前的节段计算得出的平均值。结果表明，第一，踝关节固有刚度与踝关节扭矩呈正相关，且这种关系对于长期僵硬的影响更大。第二，踝关节固有僵硬与身体摆动呈负相关，但与扭矩的关系相比，这种关系对短程僵硬的影响更强。我们得出结论，尽管这两个参数之间的因果关系尚不清楚，但较高的短程固有踝关节僵硬与减少自发摆动有关。这些结果表明，在摇摆非常小的正常安静站立状态下，脚踝固有僵硬最重要的决定因素可能是静止。在不太稳定的条件下，固有的踝关节僵硬可能更多地依赖于踝关节扭矩。
When standing, intrinsic ankle stiffness is smaller when measured using large perturbations, when sway size is large, and when background torque is low. However, there is a large variation in individual intrinsic ankle stiffness. Here we determine if individual variation has consequences for postural control. We examined the relationship between ankle stiffness, ankle torque and body sway across different individuals. Ankle stiffness was estimated in 19 standing participants by measuring torque responses to small, brief perturbations. Perturbation sizes of 0.2 & 0.9 degrees (both lasting 140 ms) measured short- and long-range stiffness respectively, while participants either stood quietly on a fixed platform or were imperceptibly tilted to reduce stability (0.1 Hz sinusoid; 0.2 & 0.4 deg). The spontaneous body sway component (natural random relatively rapid postural adjustments) and background ankle torque were averaged from sections immediately before perturbations. The results show that, first, intrinsic ankle stiffness is positively associated with ankle torque, and that this relationship is stronger for long-range stiffness. Second, intrinsic ankle stiffness is negatively associated with body sway, but, in contrast to the relationship with torque, this relationship is stronger for short-range stiffness. We conclude that high short-range intrinsic ankle stiffness is associated with reduced spontaneous sway, although the causal relationship between these two parameters is unknown. These results suggest that, in normal quiet standing where sway is very small, the most important determinant of intrinsic ankle stiffness may be stillness. In less stable conditions, intrinsic ankle stiffness may be more dependent on ankle torque.
登录
查看更多内容
影响因子：
5.5
作者：
Loram, ID;Maganaris, CN;Lakie, M
通讯作者：
Lakie, M
影响因子：
3.4
作者：
Duarte, Marcos;Freitas, Sandra M. S. F.
通讯作者：
Freitas, Sandra M. S. F.
影响因子：
5.5
作者：
DAY, BL;STEIGER, MJ;MARSDEN, CD
通讯作者：
MARSDEN, CD
影响因子：
2
作者：
Aramaki, Y;Nozaki, D;Yano, H
通讯作者：
Yano, H
影响因子：
2.4
作者：
HUNTER, IW;KEARNEY, RE
通讯作者：
KEARNEY, RE