单侧肢体电刺激或随意力量训练对双侧足背屈力量和肌肉动员能力的影响

关键词：交叉迁移  肌肉电刺激  随意收缩叠加法  最大随意收缩力量

Keywords:cross education  electromyostimulation  twitch interpolation  maximal voluntary contraction

摘要：

      目的：观察单侧肢体电刺激训练与随意力量训练是否可产生类似交叉迁移的现象，并采用电刺激与随意收缩叠加法（Twitch Interpolation，TI）评价神经系统动员肌肉力量的能力。方法：实验对象为18—30岁未经专项体育训练的健康男子大学生30名，随机分为电刺激训练组、随意收缩训练组和对照组，每组10名。训练选择右侧胫骨前肌，采用重复等长收缩模式。随意收缩训练组训练强度定为其最大随意收缩力量（MVC）的60%—70%；电刺激组的训练强度为其MVC的60%—70%；每周训练3次，每次3—5组共20min，隔日进行，周日休息，共训练6周。对照组保持日常生活和学习，期间不参加剧烈体育活动。结果：电刺激组训练侧和未训练侧的足背屈力量在训练后均有显著提高（右13.3%，左15.6%），且与随意收缩训练组相似（右15.3%，左14.8%），并与对照组(右2.5%,左-2.7%)差异有显著性（P＜0.05）；电刺激训练组双侧肌肉动员能力均有明显增强（右9.0%，左9.9%），与对照组相比差异具有显著性（P＜0.05）；随意收缩训练组的肌肉动员能力（7.4%，5.4%），与对照组相比差异没有显著性（P＞0.05）。 结论：6周单侧肢体电刺激训练和随意等长收缩训练不仅能够明显提高训练侧的肢体力量，亦能提高对侧未受训练肢体的肌肉力量，产生显著的交叉迁移效果。同时，训练导致的力量增长，特别是在电刺激组，与使用TI法观察到的肌肉动员能力的增长有关。

Abstract:

      Objective:To investigate the bilateral effect of unilateral electromyostimulation and voluntary isometric training on isometric dorsiflexion strength and capacity in muscle activation using twitch interpolation technique. Method: Thirty healthy male volunteers, aged 18-30 years, were randomly assigned into three groups(n=10 each): electromyostimulation(EMS), voluntary isometric contraction(VIM), and control(CON). In EMS and VIM groups, the right legs were trained, three sessions per week for six weeks. Each EMS session included percutaneous stimulation on the tibialis anterior muscle at 50Hz 50—100mA, to induce contraction force that was equivalent to 60%—70%maximum voluntary contraction(MVC), with duty cycles of 5s on, 10s off, for 15—20mins. The VIM session contained static dorsiflexion at 60%—70%MVC, 8 repetitions per set, for 3-5 sets, with 1 min resting intervals between sets. Result: Repeated measures ANOVA with Bonferroni adjustment showed significant(P＜0.05) increase in dorsiflexion MVC of both legs in both EMS (13.3% on the right side, 15.6% on the left) and VIM (15.3%, 14.8%), while CON showed no significant increase (2.5%, -2.7%, respectively). The muscle activation was significantly improved at both limbs in EMS group (P＜0.05, right 9.0%, left 9.9%) but not in VIM(7.4%, 5.4%) and the CON (0.6%, -0.3%) (P＞0.05), respectively. Conclusion: Unilateral electromyostimulation and voluntary isometric training significantly improved dorsiflexion strength not only at the exercised limb, but also at the contralateral limb. The increased capacity in muscle activation was responsible for much of the improved strength, particularly for the EMS training.