Quadriceps strength and fatigue assessed by magnetic stimulation of the femoral nerve in man
Quadriceps strength and fatigue assessed by magnetic stimulation of the femoral nerve in man
复制标题
通过股神经磁刺激评估人体股四头肌的力量和疲劳
作者：
M. Polkey;D. Kyroussis;C. Hamnegard;G. Mills;M. Green;J. Moxham
目前还没有一种评估股四头肌力量的非自愿方法，既能最大限度地激活肌肉，又能为受试者所接受。在10名正常受试者和10名疑似肌无力患者中，我们使用磁刺激股神经引起等长收缩，并测量抽搐张力（TwQ），表面肌电图以及最大随意收缩力（MVC）。所有受试者均在最大刺激器输出的平均83%时达到超最大值。当超最大时，TwQ是可重复的（平均变异系数3.6%，范围0.7-10.9），并与MVC良好相关（r2 = 0.83，P < 0.001）。在7名正常受试者，我们测量了TwQ之前和之后的疲劳协议; 20分钟后，TwQ的平均值为55%（范围29-77%）的基线，并保持大幅减少，在90分钟。磁股神经刺激是一种无痛，超极大的方法评估股四头肌的力量和疲劳，这是可能的价值在临床和生理研究。John Wiley & Sons，Inc.
There is no nonvolitional method of assessing quadriceps strength which both supramaximally activates the muscle and is acceptable to subjects. In 10 normal subjects and 10 patients with suspected muscle weakness we used magnetic stimulation of the femoral nerve to elicit an isometric twitch and measured twitch tension (TwQ), surface electromyogram in addition to the maximum voluntary contraction force (MVC). Supramaximality was achieved in all subjects at a mean of 83% of maximum stimulator output. When supramaximal, TwQ was reproducible (mean coefficient of variation 3.6%, range 0.7–10.9) and correlated well with MVC (r2 = 0.83, P < 0.001). In 7 normal subjects we measured TwQ before and after a fatiguing protocol; after 20 min TwQ was a mean of 55% (range 29–77%) of baseline and remained substantially reduced at 90 min. Magnetic femoral nerve stimulation is a painless, supramaximal method of assessing quadriceps strength and fatigue which is likely to be of value in clinical and physiological studies. © 1996 John Wiley & Sons, Inc.