Center of mass velocity-based predictions in balance recovery following pelvis perturbations during human walking
Center of mass velocity-based predictions in balance recovery following pelvis perturbations during human walking
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DOI：
10.1242/jeb.129338
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发表时间：
2016-05-15
影响因子：
2.8
通讯作者：
van der Kooij, H.
中科院分区：
文献类型：
--
作者：
Vlutters, M.;van Asseldonk, E. H. F.;van der Kooij, H.
在许多简单的步行模型中，脚的放置决定了压力中心的位置和地面反作用力分量，而人类可以在脚接触后调节这些方面。由于这些差异，目前还不清楚模型的预测在多大程度上对人类行走有效。然而，模型模拟和人体实验数据都表明，质心（COM）速度在调节稳定行走中起着重要作用。在这里，扰动的人类行走进行了研究，以确定在脚跟罢工和脚趾关闭与脚放置位置相对于COM，即将到来的压力中心的位置相对于COM，和地面的反作用力的水平COM速度的关系。10名健康受试者在0.63和1.25 m/s（-1）的跑步机行走时，在脚趾离地时接受不同程度的骨盆内外侧和前后扰动。在脚跟罢工后的扰动，恢复中外侧扰动涉及中外侧脚的位置调整成比例的中外侧COM速度。与此相反，对于前后扰动，没有显着的前后脚放置调整发生在这个脚跟罢工。然而，在这两个方向上的COM速度在脚跟罢工线性相关的压力中心的位置在随后的脚趾。这种关系受到步行速度的影响，是，对于缓慢的速度，在与COM速度为基础的控制策略，以前应用的线性倒立摆模型。最后，步态相持续时间的变化表明，行动的时机可以发挥重要作用，扰动恢复。
In many simple walking models, foot placement dictates the center of pressure location and ground reaction force components, whereas humans can modulate these aspects after foot contact. Because of the differences, it is unclear to what extent predictions made by models are valid for human walking. Yet, both model simulations and human experimental data have previously indicated that the center of mass (COM) velocity plays an important role in regulating stable walking. Here, perturbed human walking was studied to determine the relationship of the horizontal COM velocity at heel strike and toe-off with the foot placement location relative to the COM, the forthcoming center of pressure location relative to the COM, and the ground reaction forces. Ten healthy subjects received mediolateral and anteroposterior pelvis perturbations of various magnitudes at toe-off, during 0.63 and 1.25 m s(-1) treadmill walking. At heel strike after the perturbation, recovery from mediolateral perturbations involved mediolateral foot placement adjustments proportional to the mediolateral COM velocity. In contrast, for anteroposterior perturbations, no significant anteroposterior foot placement adjustment occurred at this heel strike. However, in both directions the COM velocity at heel strike related linearly to the center of pressure location at the subsequent toe-off. This relationship was affected by the walking speed and was, for the slow speed, in line with a COM velocity-based control strategy previously applied by others in a linear inverted pendulum model. Finally, changes in gait phase durations suggest that the timing of actions could play an important role during the perturbation recovery.