Xu Lin, Rabotti Chiara, Mischi Massimo
IEEE Trans Neural Syst Rehabil Eng. 2016 Dec;24(12):1284-1293. doi: 10.1109/TNSRE.2015.2493358. Epub 2015 Oct 26.
Vibration exercise (VE) has been suggested to improve muscle strength and power performance, due to enhanced neuromuscular demand. However, understanding of the most appropriate VE protocols is lacking, limiting the optimal use of VE in rehabilitation programs. In this study, the fatiguing effect of vibration at different frequencies was investigated by employing a force-modulation VE system. Twenty volunteers performed 12-s isometric contractions of the biceps brachii with a load consisting of a baseline force of 80% of their maximum voluntary contraction (MVC) and a superimposed sinusoidal force at 0 (control condition with no vibration), 20, 30, and 40 Hz. Mechanical fatigue was estimated by assessment of MVC decay after each task while myoelectric fatigue was estimated by analysis of multichannel electromyography (EMG) signals recorded during VE. EMG conduction velocity, spectral compression, power, and fractal dimension were estimated as indicators of myoelectric fatigue. Our results suggest vibration, in particular at 30 Hz, to produce a larger degree of fatigue as compared to control condition. These results motivate further research aiming at introducing VE in rehabilitation programs with improved training protocols.
由于神经肌肉需求增加，振动训练（VE）被认为可以提高肌肉力量和功率表现。然而，目前缺乏对最合适的VE方案的了解，这限制了VE在康复计划中的最佳应用。在本研究中，通过使用力调制VE系统，研究了不同频率振动的疲劳效应。20名志愿者进行了肱二头肌12秒的等长收缩，负荷包括其最大自主收缩（MVC）的80%的基线力以及在0（无振动的对照条件）、20、30和40Hz的叠加正弦力。通过评估每个任务后MVC的衰减来估计机械疲劳，而通过分析VE期间记录的多通道肌电图（EMG）信号来估计肌电疲劳。EMG传导速度、频谱压缩、功率和分形维数被估计为肌电疲劳的指标。我们的结果表明，与对照条件相比，振动，特别是30Hz的振动，会产生更大程度的疲劳。这些结果促使进一步的研究，旨在将VE引入具有改进训练方案的康复计划中。
