Department of Rehabilitation Science, Kobe University Graduate School of Health Sciences, Tomogaoka, Suma-Ku, Kobe, Hyogo, Japan.
Miyabinosato Home-visit nursing care station, Patio Akashi 1F, Uozumicho, Nakao, Akashi, Hyogo, Japan.
PLoS One. 2018 May 10;13(5):e0195309. doi: 10.1371/journal.pone.0195309. eCollection 2018.
High plantar flexor moment during the stance phase is known to cause high plantar pressure under the forefoot; however, the effects on plantar pressure due to a change of gastrocnemius medialis (GM) activity during gait, have not been investigated to date. Reciprocal inhibition is one of the effects of electrical stimulation (ES), and is the automatic antagonist alpha motor neuron inhibition which is evoked by excitation of the agonist muscle. The aim of this study was to investigate the influences of ES of the tibialis anterior (TA) on plantar pressure and the GM activity during gait in healthy adults. ES was applied to the TAs of twenty healthy male adults for 30 minutes at the level of intensity that causes a full range of dorsiflexion in the ankle (frequency; 50 Hz, on-time; 10 sec, off-time; 10 sec). Subjects walked 10 meters before and after ES, and we measured the peak plantar pressure (PP), pressure time integral (PTI), and gait parameters by using an F-scan system. The percentage of integrated electromyogram (%IEMG), active time, onset time, peak time, and cessation time of TA and GM were calculated. PP and PTI under the forefoot, rear foot, and total plantar surface significantly decreased after the application of ES. Meanwhile, changes of gait parameters were not observed. %IEMG and the active time of both muscles did not change; however, onset time and peak time of GM became significantly delayed. ES application to the TA delayed the timing of onset and peak in the GM, and caused the decrease of plantar pressure during gait. The present results suggest that ES to the TA could become a new method for the control of plantar pressure via modulation of GM activity during gait.
在站立阶段，跖屈肌产生的力矩较高会导致前足下的足底压力较高；然而，迄今为止，还没有研究过步态中腓肠肌内侧（GM）活动的变化对足底压力的影响。交互抑制是电刺激（ES）的影响之一，是由兴奋引起的拮抗剂α运动神经元自动抑制。本研究旨在探讨胫骨前肌（TA）的 ES 对健康成年人步态中足底压力和 GM 活动的影响。将 ES 应用于 20 名健康男性成年人的 TAs，强度达到引起踝关节全背屈的程度（频率；50 Hz，通电时间；10 秒，断电时间；10 秒）。在 ES 前后，受试者行走 10 米，我们使用 F-scan 系统测量峰值足底压力（PP）、压力时间积分（PTI）和步态参数。计算 TA 和 GM 的积分肌电图百分比（%IEMG）、活动时间、起始时间、峰值时间和停止时间。ES 应用后，前足、后足和整个足底表面的 PP 和 PTI 显著降低。同时，观察到步态参数没有变化。%IEMG 和两块肌肉的活动时间没有变化；然而，GM 的起始时间和峰值时间明显延迟。ES 应用于 TA 延迟了 GM 的起始和峰值时间，导致步态中足底压力降低。本研究结果表明，ES 应用于 TA 可能成为通过调节步态中 GM 活动来控制足底压力的一种新方法。
