Berry Helen R, Tate Rothwelle J, Conway Bernard A
Centre for Excellence in Rehabilitation Research, Department of Biomedical Engineering, University of Strathclyde, Glasgow, United Kingdom.
Strathclyde Institute for Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom.
PLoS One. 2017 Apr 5;12(4):e0173846. doi: 10.1371/journal.pone.0173846. eCollection 2017.
Transcutaneous spinal direct current stimulation (tsDCS) is a non-invasive neuromodulatory intervention that has been shown to modify excitability in spinal and supraspinal circuits in animals and humans. Our objective in this study was to explore the functional neuromodulatory potential of tsDCS by examining its immediate and lasting effects over the repeated performance of a whole body maximal exercise in healthy volunteers. Using a double-blind, randomized, crossover, sham-controlled design we investigated the effects of 15 min of anodal tsDCS on repeated vertical countermovement jump (VCJ) performance at 0, 20, 60, and 180 minutes post-stimulation. Measurements of peak and take-off velocity, vertical displacement, peak power and work done during countermovement and push-off VCJ phases were derived from changes in vertical ground reaction force (12 performance parameters) in 12 healthy participants. The magnitude and direction of change in VCJ performance from pre- to post-stimulation differed significantly between sham and active tsDCS for 7 of the 12 VCJ performance measures (P < 0.05). These differences comprised of a post-sham fatigue in VCJ displacement/work done, peak to peak power and take-off velocity, and a resilience to this fatigue effect post-active tsDCS. In addition there was also an enhancement of countermovement performance and total work done (P < 0.05). These changes did not vary across repeated VCJ performances over time post-tsDCS (P > 0.05). Our original findings demonstrate that one single session of anodal tsDCS in healthy subjects can prevent fatigue and maintain or enhance different aspects of whole body explosive motor power over repeated sets of VCJs performed over a period of three hours. The observed effects are discussed in relation to alterations in central fatigue mechanisms, muscle contraction mode during jump execution and changes in spinal cord excitability. These findings have important implications for power endurance sport performance and for neuromotor rehabilitation.
经皮脊髓直流电刺激（tsDCS）是一种非侵入性神经调节干预措施，已被证明可改变动物和人类脊髓及脊髓上回路的兴奋性。本研究的目的是通过检查tsDCS对健康志愿者全身最大运动重复表现的即时和持久影响，来探索其功能性神经调节潜力。我们采用双盲、随机、交叉、假刺激对照设计，研究了15分钟阳极tsDCS对刺激后0、20、60和180分钟重复垂直反向运动跳跃（VCJ）表现的影响。通过测量12名健康参与者垂直地面反作用力的变化（12个表现参数），得出反向运动和蹬地VCJ阶段的峰值和起跳速度、垂直位移、峰值功率和做功。在12项VCJ表现测量指标中，有7项指标在假刺激和活性tsDCS之间，刺激前到刺激后的VCJ表现变化幅度和方向存在显著差异（P<0.05）。这些差异包括假刺激后VCJ位移/做功、峰峰值功率和起跳速度的疲劳，以及活性tsDCS后对这种疲劳效应的恢复能力。此外，反向运动表现和总做功也有所增强（P<0.05）。这些变化在tsDCS后的不同时间重复VCJ表现中没有差异（P>0.05）。我们的原始研究结果表明，健康受试者单次阳极tsDCS可预防疲劳，并在三小时内重复进行的多组VCJ中维持或增强全身爆发力的不同方面。结合中枢疲劳机制的改变、跳跃执行过程中的肌肉收缩模式以及脊髓兴奋性的变化，对观察到的效应进行了讨论。这些发现对耐力运动表现和神经运动康复具有重要意义。
