Influence of lateral destabilization on compensatory stepping responses
Influence of lateral destabilization on compensatory stepping responses
复制标题
DOI：
10.1016/0021-9290(95)00053-4
复制
发表时间：
1996-03-01
影响因子：
2.4
通讯作者：
Perry, SD
中科院分区：
文献类型：
--
作者：
Maki, BE;McIlroy, WE;Perry, SD
以往对姿势扰动的补偿性步进的研究主要集中在向前或向后的步进；然而，向其他方向步进的能力同样具有重要的功能，因为日常生活中遇到的扰动通常包括横向成分。本研究的主要目的是从以下几个方面确定侧向失稳对代偿性踏步反应的影响：(1)摆动腿的选择，(2)摆动腿的准备卸载，(3)摆动轨迹的空间和时间特征。使用一种新颖的多方向移动平台，在8个水平方向上对10名健康年轻人进行了瞬时摄动。扰动的大小在很大范围内发生了不可预测的变化，受试者被指示尽量不要踩，以阻止预先计划的“意志性”脚步移动。在对侧向失稳的步进反应中，96%的主要策略是摆动被扰动卸载的腿。这种策略允许更快的抬脚，但需要更长、更复杂的摆动轨迹，而不是摆动受干扰的腿。与向前和向后两步相比，在扰动中增加一个横向分量，平均导致下地时间减少20%(90ms)，步长增加20%(7 Cm)，摆动持续时间增加70%(110ms)。结果清楚地表明，对非矢状扰动的补偿性步进反应强烈地受到生物力学约束和承受力的影响，而这些约束和承受力并不影响传统上研究的向前和向后步进行为。这些发现强调了从多个方向评估姿势反应的必要性，以便更充分地了解如何在日常生活的紧急情况下保持平衡。
Previous studies of compensatory stepping, in response to postural perturbation, have focussed on forward or backward stepping; however, the ability to step in other directions is of equal functional importance, since the perturbations encountered in daily life may often include a lateral component. The primary objective of this study was to determine how lateral destabilization affects the compensatory stepping response, in terms of: (1) swing-leg selection, (2) preparatory unloading of the swing leg, and (3) spatial and temporal characteristics of the swing trajectory. A novel multi-directional moving platform was used to apply transient perturbations in eight horizontal directions, in 10 healthy young adults. Perturbation magnitude was varied unpredictably over a wide range and subjects were instructed to try not to step, so as to discourage preplanned 'volitional' foot movement. The predominant strategy, seen in 96% of stepping responses to lateral destabilization, was to swing the leg that was unloaded by the perturbation. This strategy allowed a much more rapid foot-lift but required a longer and more complex swing trajectory, compared to responses where the perturbation-loaded leg was swung. When compared to forward and backward steps, the addition of a lateral component to the perturbation led to a 20% (90 ms) reduction in time to foot-off, a 20% (7 cm) increase in step length and a 70% (110 ms) increase in swing duration, on average. The results clearly demonstrate that compensatory stepping responses to non-sagittal perturbations are strongly influenced by biomechanical constraints and affordances that do not affect the forward and backward stepping behaviour that has been studied traditionally. These findings underscore the need to assess postural responses in multiple directions, in order to understand more fully how balance is maintained in the exigencies of everyday life.