Deschenes Michael R, McCoy Raymond W, Holdren Ashley N, Eason Margaret K
Department of Kinesiology, The College of William and Mary, Williamsburg, VA 23187-8795, USA.
Eur J Appl Physiol. 2009 Apr;105(6):889-97. doi: 10.1007/s00421-008-0974-5. Epub 2009 Jan 6.
Muscle unloading results in decreased strength. This is partly attributed to reduced neural activation. This study examined whether men and women experienced different adaptations to muscle unloading. Ten men (21.4 +/- 0.8 years; mean +/- SE) and ten women (20.9 +/- 0.2 years) were subjected to 1 week of muscle unloading. Muscle function was quantified during knee extensions before, and following unloading. Electromyography (EMG) was assessed during maximal isometric contractions before, and after unloading. Results showed greater (P < 0.05) unloading-induced decrement in muscle performance in women than men. The loss of peak torque was significantly correlated (r = 0.69) with the decline in EMG consequent to unloading, and women displayed significantly larger reductions in EMG. These findings indicate that: (1) women are more affected by muscle unloading than men, and (2) gender-related differences in strength declines are associated with similar disparities in the nervous system's capacity to maximally stimulate muscle.
肌肉失用会导致力量下降。这部分归因于神经激活的减少。本研究调查了男性和女性对肌肉失用是否有不同的适应性变化。10名男性(21.4±0.8岁;平均值±标准误)和10名女性(20.9±0.2岁)经历了为期1周的肌肉失用。在失用前后,对膝关节伸展过程中的肌肉功能进行了量化。在最大等长收缩过程中,分别于失用前后评估了肌电图(EMG)。结果显示,与男性相比,女性因失用导致的肌肉性能下降幅度更大(P<0.05)。峰值扭矩的损失与失用后肌电图的下降显著相关(r=0.69),并且女性的肌电图下降幅度明显更大。这些发现表明:(1)女性比男性更容易受到肌肉失用的影响,(2)力量下降的性别差异与神经系统最大程度刺激肌肉的能力的类似差异有关。