Neuromechanics of foot function during dynamic balance reactions

这项研究计划是为了更好地了解与环境接触的感觉信息是如何实现的，以及足部的机械考虑是如何相互关联的，以便在运动过程中产生有效和功能性的平衡反应。该计划将允许在非常专业的方法和科学技术方面培训高素质的人员。潜在的动机是了解脚下的接触压力/力如何转化为神经信号，然后如何产生功能结果。调查的几个组成部分将建立在正在进行的研究项目的先前发现的基础上。第一个组成部分将确定足感减少/促进对步态中意外扰动产生平衡反应的能力的影响。其次，细丝肌电图（EMG）是一种可以定量记录下肢非常特定的深层肌肉活动的方法，而表面肌电图将用于了解肌肉活动模式，用于对意外的步态扰动产生平衡反应。第三部分将包括理解机械调节（足弓支撑，鞋类）对产生平衡反应的影响。这些实验将评估运动和肌肉激活模式是否转化为功能平衡恢复模式（运动学和动力学分析）以成功保持平衡。这些将系统地评估足部感觉和足部力学对运动过程中功能显著平衡反应的贡献。实验条件将包括水平表面步态和扰动步态，其中意想不到的外部扰动可能涉及表面平移或改变表面方向。这些条件将在参与者有正常的足感、减少的足感（通过低温）和促进的足感时进行。这种方法可以完整地评估从环境中接收机械接触信息的过程，以及有多少信息被转移到中枢神经系统，然后转移到肌肉活动，最后转移到功能平衡反应。因此，通过选择性地减少或促进足部的感觉，可以系统地评估机械感受器的作用。这项研究计划的预期意义在于两个重要领域。首先，量化足底-体表机械接收对运动平衡控制的贡献。其次，这种理解可以为一种辅助装置的发展提供重要信息，这种辅助装置可以促进由于年龄相关的脚底感觉恶化而有跌倒风险的老年人的足底机械接受。

This research program is to provide a better understanding of how sensory information about contact with the environment is realized and how mechanical considerations of the foot are interrelated in order to have efficient and functional balance reactions during locomotion. This program will allow for the training of highly qualified personnel in very specialized methodological and scientific techniques. The underlying motivation is to understand how contact pressures/forces under the feet are being transformed into neural signals and then how that is produced as functional outcomes. There are several components of investigation that will build upon previous findings in the ongoing research program. The first component will determine the effects of foot sensation reduction/faciltation on the ability to generate balance reactions to unexpected perturbations during gait. Secondly, fine-wire electromyography (EMG), a method that can quantitatively record muscle activity from very specific deep muscles of the lower limb, and surface EMG will be used to understand the muscle activity patterns used to generate balance reactions to unexpected gait perturbations. The third component will involve understanding the effects of mechanical modulations (arch support, footwear) on producing balancing reactions. These experiments will evaluate if the movements and muscle activation patterns transform into functional balance recovery patterns (kinematic and kinetic analysis) to successfully maintain balance. These will systematically evaluate the contribution of the foot sensation and foot mechanics towards functionally significant balance responses during locomotion. The experimental conditions will consist of level surface gait and perturbed gait where unexpected external perturbations may involve surface translation or change surface orientation. These conditions will be performed when the participants have normal foot sensation, reduced foot sensation (via hypothermia) and when the foot sensation is facilitated. This approach will allow for a complete evaluation of the process of receiving mechanical contact information from the environment and how much of the information is transferred into the CNS, then to muscle activity and finally to functional balance responses. Thus by selectively reducing or facilitating the sensation from the feet the contribution of the mechanoreceptors can be systematically evaluated. The expected significance of this research program is in two areas of importance. Firstly, quantifying the contribution of plantar-surface mechanoreception to the balance control of locomotion. Secondly, this understanding could provide important information for the advancement of an assistive device that would facilitate plantar-surface mechanoreception for older adults whom are at risk of falling due to age-related deterioration of the sensation from the bottom of the feet.