At the typical walking speeds of healthy humans, step placement seems to be the primary strategy to maintain gait stability, with ankle torques and upper body momentum providing additional compensation. The average walking speeds of populations with an increased risk of falling, however, are much slower and may require differing control strategies. The purpose of this study was to analyse mediolateral gait stability and the contributions of the different control strategies at very slow walking speeds. We analysed an open dataset including kinematics and kinetics from eight healthy subjects walking at speeds from 0.1 to 0.6 m s−1 as well as a self-selected speed. As gait speed slowed, we found that the margin of stability (MoS) decreased linearly. Increased lateral excursions of the extrapolated centre of mass, caused by increased lateral excursions of the trunk, were not compensated for by an equivalent increase in the lateral centre of pressure, leading to decreased MoS. Additionally, both the ankle eversion torque and hip abduction torque at the minimum MoS event increased at the same rate as gait speed slowed. These results suggest that the contributions of both the ankle and the upper body to stability are more crucial than stepping at slow speeds, which have important implications for populations with slow gait and limited motor function.

中文翻译：

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上身和脚踝策略可以补偿在非常慢的步行速度下横向稳定性降低

在健康人的典型步行速度下，踏步似乎是保持步态稳定性的主要策略，脚踝扭矩和上身动量提供额外的补偿。然而，跌倒风险增加的人群的平均步行速度要慢得多，可能需要不同的控制策略。本研究的目的是分析中间外侧步态稳定性和不同控制策略在非常慢的步行速度下的贡献。我们分析了一个开放数据集，包括八名健康受试者以 0.1 到 0.6 ms-1 的速度以及自行选择的速度行走的运动学和动力学。随着步态速度减慢，我们发现稳定性裕度 (MoS) 呈线性下降。外推质心的横向偏移增加，由躯干横向偏移增加引起的压力没有通过横向压力中心的等效增加来补偿，导致 MoS 减少。此外，在最小 MoS 事件下，踝外翻扭矩和髋外展扭矩都以与步态速度减慢相同的速率增加。这些结果表明，脚踝和上身对稳定性的贡献比慢速行走更为重要，这对步态缓慢和运动功能有限的人群具有重要意义。