Individuals with stroke often have difficulty modulating their lateral foot placement during gait, a primary strategy for maintaining lateral stability. Our purpose was to understand how individuals with and without stroke adapt their lateral foot placement when walking in an environment that alters center of mass (COM) dynamics and the mechanical requirement to maintain lateral stability. The treadmill walking environments included: 1) a Null Field- where no forces were applied, and 2) a Damping Field- where external forces opposed lateral COM velocity. To evaluate the response to the changes in environment, we quantified the correlation between lateral COM state and lateral foot placement (FP), as well as step width mean and variability. We hypothesized the Damping Field would produce a stabilizing effect and reduce both the COM-FP correlation strength and step width compared to the Null Field. We also hypothesized that individuals with stroke would have a significantly weaker COM-FP correlation than individuals without stroke. Surprisingly, we found no differences in COM-FP correlations between the Damping and Null Fields. We also found that compared to individuals without stroke in the Null Field, individuals with stroke had weaker COM-FP correlations (Paretic <; Control: p =0.001, Non-Paretic <; Control: p =0.007) and wider step widths (p =0.001). Our results suggest that there is a post-stroke shift towards a non-specific lateral stabilization strategy that relies on wide steps that are less correlated to COM dynamics than in individuals without stroke.

中文翻译：

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多变环境中足部横向放置协调的中风后适应


中风患者通常难以在步态过程中调节脚外侧的位置，而这是维持侧向稳定性的主要策略。我们的目的是了解患有和未患有中风的人在改变质心 (COM) 动力学和维持横向稳定性的机械要求的环境中行走时如何调整其横向足部位置。跑步机行走环境包括：1) 零场 - 没有施加力，2) 阻尼场 - 外力与横向 COM 速度相反。为了评估对环境变化的响应，我们量化了横向 COM 状态和横向足部放置 (FP) 之间的相关性，以及步宽平均值和变异性。我们假设与零场相比，阻尼场会产生稳定效果并降低 COM-FP 相关强度和步长。我们还假设患有中风的个体的 COM-FP 相关性明显弱于没有中风的个体。令人惊讶的是，我们发现阻尼场和零场之间的 COM-FP 相关性没有差异。我们还发现，与零场中没有中风的个体相比，中风个体的 COM-FP 相关性较弱（麻痹 <；对照：p = 0.001，非麻痹 <；对照：p = 0.007）和更宽的步长（p = 0.001）。我们的结果表明，中风后存在向非特异性横向稳定策略的转变，该策略依赖于宽步，与未中风的个体相比，与 COM 动态的相关性较小。