Department of Kinesiology and Physical Education, Faculty of Science, Wilfrid Laurier University, 75 University Ave. West, Waterloo, ON N2L 3C5, Canada.
Department of Human Health and Nutritional Sciences, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.
Foot (Edinb). 2022 Sep;52:101904. doi: 10.1016/j.foot.2022.101904. Epub 2022 Jan 6.
Foot orthoses (FO) are used as a treatment for biomechanical abnormalities, overuse injuries, and neuropathologies, but study of their mechanism remains inconclusive. The neuromotor paradigm has proposed that FOs may manipulate sensory input from foot sole skin to reduce muscle activity for movement optimization. This review argues that a FO likely alters the incoming mechanical stimuli transmitted via cutaneous mechanoreceptors and nociceptors as the foot sole interfaces with the surface of the orthotic. Thus, all FOs with or without intentional sensory facilitation, likely changes sensory information from foot sole cutaneous afferents. Additionally, in light of understanding and applying knowledge pertaining to the cutaneous reflex loop circuitry, FO's increasing sensory input to the motorneuron pool can change EMG to either reflex sign (increase or decrease). The purpose of this scoping review was to synthesize FO and sensory augmentation literature and summarize how FO designs can capitalize on foot sole skin to modulate lower limb electromyography (EMG). Six database searches resulted in 30 FO studies and 22 sensory studies that included EMG as an outcome measure. Results revealed task and phase specific responses with some consistencies in EMG outcomes between testing modalities, however many inconsistencies remain. Electrical stimulation reflex research provides support for a likely sensory-to-motor factor contributing to muscle activity modulation when wearing FOs. The discussion divides trends in FO treatment modalities by desired increase or decrease in each compartment musculature. The results of this review provides a benchmark for future academics and clinicians to advance literature in support of a revised neuromotor paradigm while highlighting the importance of foot sole skin in FO design.
足矫形器（FO）被用作治疗生物力学异常、过度使用损伤和神经病理学的方法，但对其机制的研究仍不确定。神经运动范式提出，FO 可能通过足底皮肤的感觉输入来操纵感觉输入，以优化运动的肌肉活动。本综述认为，FO 可能会改变足底与矫形器表面接触时通过皮肤机械感受器和伤害感受器传递的传入机械刺激。因此，所有具有或不具有有意感觉促进作用的 FO 都可能改变足底皮肤传入的感觉信息。此外，鉴于对皮肤反射回路电路的理解和应用知识，FO 对运动神经元池的感觉输入增加可以改变肌电图（增加或减少）。本综述的目的是综合 FO 和感觉增强文献，并总结 FO 设计如何利用足底皮肤来调节下肢肌电图（EMG）。六项数据库搜索共得到 30 项 FO 研究和 22 项感觉研究，其中 EMG 作为一个结果测量。结果显示，在某些测试模式之间存在与任务和阶段相关的特定反应，但仍存在许多不一致之处。电刺激反射研究为 FO 治疗方式提供了支持，即当穿着 FO 时，感觉输入可能对肌肉活动调节产生影响。讨论通过每个肌肉部位的期望增加或减少来划分 FO 治疗方式的趋势。本综述的结果为未来的学者和临床医生提供了一个基准，以支持修订后的神经运动范式的文献，并强调了 FO 设计中足底皮肤的重要性。
