Abstract

Purpose/aim of the study: Generation of smooth movement relies on the central nervous system (CNS) having information from the visual, vestibular and somatosensory systems to effectively execute motor behaviour. Recently, cutaneous afferent inputs have been linked to lower leg motorneuron pools, resulting in a growing interest of adding texture to the plantar foot sole interface as a novel method to facilitate cutaneous feedback. The aim of this study was to characterize the changes in magnitude and temporal organization of muscle activity, and to investigate motor output changes from enhanced tactile feedback during perturbed gait termination.

Materials and methods: Thirty young adults experienced an unpredictable platform perturbation when completing planned gait termination. The study manipulated two experimental variables: 1) direction of platform tilt (anterior, posterior, medial, lateral), and 2) foot sensory facilitation (non-facilitated, facilitated). Upper and lower leg EMG onset, cessation time and integrated EMG (iEMG) were measured in addition to common gait parameters (walking velocity, step length, step width).

Results: Gait termination over a textured surface resulted in significantly earlier upper leg EMG onset times and modified iEMG of rectus femoris, vastus medialis and biceps femoris muscles.

Conclusions: Results of this study suggest that the addition of cutaneous feedback under the plantar-surface of the foot increases the ability to generate an earlier muscle response, consequently improving response ability to an unexpected perturbation. Secondly, enhanced tactile feedback appears to inform the CNS of the magnitude of the threat to the balance control system, providing additional insight into how the CNS uses enhanced tactile feedback during a gait termination task.

摘要

研究的目的/目的：平滑运动的产生依赖于中枢神经系统 (CNS) 具有来自视觉、前庭和体感系统的信息，以有效执行运动行为。最近，皮肤传入输入与小腿运动神经元池相关联，导致越来越多的兴趣将纹理添加到足底足底界面，作为一种促进皮肤反馈的新方法。本研究的目的是表征肌肉活动的幅度和时间组织的变化，并研究在扰动步态终止期间增强的触觉反馈引起的运动输出变化。

材料和方法： 30 名年轻人在完成计划的步态终止时经历了不可预测的平台扰动。该研究操纵了两个实验变量：1) 平台倾斜的方向（前、后、内侧、外侧），和 2）足部感觉促进（非促进、促进）。除了常见的步态参数（步行速度、步长、步宽）外，还测量了大腿和小腿肌电图开始、停止时间和综合肌电图 (iEMG)。

结果：步态终止了纹理表面造成显著前面大腿EMG起效时间和修改的股直肌，股内侧肌和股二头肌肌肉的IEMG。

结论：这项研究的结果表明，在足底表面下增加皮肤反馈增加了产生较早肌肉反应的能力，从而提高了对意外扰动的反应能力。其次，增强的触觉反馈似乎可以告知 CNS 对平衡控制系统的威胁程度，从而进一步了解 CNS 如何在步态终止任务期间使用增强的触觉反馈。