Neuromechanics of foot function during dynamic balance reactions

这项研究计划旨在更好地了解如何实现与环境接触的感觉信息，以及如何将足部的机械因素相互关联，以便在运动过程中产生有效和功能性的平衡反应。该方案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。有几个组成部分的调查，将建立在以前的发现，在正在进行的研究计划。第一部分将确定足部感觉减少/促进对步态期间对意外扰动产生平衡反应的能力的影响。其次，细导线肌电图（EMG），一种可以定量记录下肢非常特定的深层肌肉的肌肉活动的方法，以及表面EMG将用于了解用于对意外步态扰动产生平衡反应的肌肉活动模式。第三部分将涉及了解机械调节（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性重要平衡反应的贡献。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。当参与者的足部感觉正常、足部感觉降低（通过体温过低）以及足部感觉得到促进时，将执行这些条件。这种方法将允许从环境中接收机械接触信息的过程的完整评估，以及有多少信息被转移到CNS，然后到肌肉活动，最后到功能平衡反应。因此，通过选择性地减少或促进来自足部的感觉，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，这种理解可以为辅助设备的进步提供重要信息，该辅助设备将有助于老年人的足底表面机械感受，这些老年人由于与年龄相关的足底感觉恶化而有跌倒的风险。

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.