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，以及脚的机械考虑是如何相互关联的，以便在运动过程中有有效和功能上的平衡反应。该方案将允许在非常专门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/力是如何转化为神经信号的，然后是如何作为功能结果产生的。调查的几个组成部分将建立在正在进行的研究计划中之前的发现基础上。第一个部分将确定足部感觉减少/便利对步态期间对意外干扰产生平衡反应的能力的影响。其次，细丝肌电图(EMG)，一种可以定量记录非常特定的下肢深部肌肉活动的方法，以及表面EMG将被用来了解肌肉活动模式，用于对意外的步态扰动产生平衡反应。第三个部分将涉及了解机械调节(拱形支撑、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变为功能性平衡恢复模式(运动学和运动学分析)，以成功保持平衡。这些将系统地评估足部感觉和足部力学在运动过程中对功能性显著平衡反应的贡献。实验条件包括水平表面步态和扰动步态，其中意外的外部扰动可能涉及表面平移或改变表面方向。当参与者有正常的足感、减少的足感(通过体温降低)和促进足感时，就会出现这些情况。这种方法将允许对从环境中接收机械接触信息的过程进行完整的评估，以及有多少信息被传递到中枢神经系统，然后传递到肌肉活动，最后传递到功能平衡反应。因此，通过选择性地减少或促进脚部的感觉，可以系统地评估机械感受器的贡献。这项研究计划的预期意义在于两个重要领域。首先，量化足底表面机械感受对运动平衡控制的贡献。其次，这一认识可以为一种辅助装置的发展提供重要信息，该装置将促进老年人的足底表面机械接收，这些老年人由于年龄相关的脚底感觉恶化而面临摔倒的风险。

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.