Background

Control of dynamic balance in human walking is essential to remain stable and can be parameterized by the margins of stability. While frontal and sagittal plane margins of stability are often studied in parallel, they may covary, where increased stability in one plane could lead to decreased stability in the other. Hypothetically, this negative covariation may lead to critically low lateral stability during step lengthening.

Research question

Is there a relationship between frontal and sagittal plane margins of stability in able-bodied humans, during normal walking and imposed step lengthening?

Methods

Fifteen able-bodied adults walked on an instrumented treadmill in a normal walking and a step lengthening condition. During step lengthening, stepping targets were projected onto the treadmill in front of the participant to impose longer step lengths. Covariation between frontal and sagittal plane margins of stability was assessed with linear mixed-effects models for normal walking and step lengthening separately.

Results

We found a negative covariation between frontal and sagittal plane margins of stability during normal walking, but not during step lengthening.

Significance

These results indicate that while a decrease in anterior instability may lead to a decrease in lateral stability during normal walking, able-bodied humans can prevent lateral instability due to this covariation in critical situations, such as step lengthening. These findings improve our understanding of adaptive dynamic balance control during walking in able-bodied humans and may be utilized in further research on gait stability in pathological and aging populations.

中文翻译：

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健全人行走前后稳定边缘与中外侧稳定边缘的关系

背景

控制人类行走中的动态平衡对于保持稳定至关重要，并且可以通过稳定性边界进行参数化。虽然额面和矢状面的稳定性边缘经常被并行研究，但它们可能是共变的，其中一个平面的稳定性增加可能导致另一个平面的稳定性降低。假设，这种负协变可能会导致步长期间的横向稳定性极低。

研究问题

在正常步行和强加步长期间，身体健全的人的正面和矢状面稳定性边缘之间是否存在关系？

方法

十五名身体健全的成年人在仪器跑步机上以正常步行和步长条件行走。在步长延长过程中，步长目标被投射到参与者面前的跑步机上，以施加更长的步长。使用线性混合效应模型分别评估正常步行和步长延长的正面和矢状面稳定性边缘之间的协变。

结果

我们发现在正常步行过程中，额状面和矢状面的稳定性边缘之间存在负协变，但在步长期间则不然。

意义

这些结果表明，虽然前部不稳定的减少可能会导致正常行走期间横向稳定性的降低，但身体健全的人可以防止由于这种协变在关键情况下（例如步长加长）造成的横向不稳定。这些发现提高了我们对健全人行走过程中适应性动态平衡控制的理解，并可用于进一步研究病理和老龄化人群的步态稳定性。