疲劳期间人体比目鱼肌的反射抑制

Reflex inhibition of human soleus muscle during fatigue.

Garland S J, McComas A J

Department of Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.

J Physiol. 1990 Oct;429:17-27. doi: 10.1113/jphysiol.1990.sp018241.

Human soleus muscles were fatigued under ischaemic conditions by intermittent stimulation at 15 Hz. When maximal voluntary plantarflexion was then attempted, the loss of torque was found to be associated with a reduction in voluntary EMG activity. 2. The decrease in EMG activity could not have been due to 'exhaustion' of descending motor drive in the central nervous system since fatigue had been induced by electrical stimulation of peripheral nerve fibres. Similarly, the decrease could not be explained by changes at the neuromuscular junction or muscle fibre membrane, since changes in the M wave (evoked muscle compound action potential) were relatively modest. 3. When the excitability of the soleus motoneurones was tested during fatigue, using the H (Hoffmann) reflex, it was found to be significantly reduced. Control experiments with ischaemia or electrical stimulation, but without fatigue, failed to demonstrate any significant effects on reflex excitability. 4. The findings in this study favour the concept of reflex inhibition of alpha-motoneurones during fatigue.

通过以15赫兹的频率进行间歇性刺激，使人的比目鱼肌在缺血条件下疲劳。随后尝试最大自主跖屈时，发现扭矩的丧失与自主肌电图活动的减少有关。2. 肌电图活动的减少不可能是由于中枢神经系统中下行运动驱动的“耗尽”，因为疲劳是通过外周神经纤维的电刺激诱发的。同样，这种减少也不能用神经肌肉接头或肌纤维膜的变化来解释，因为M波（诱发的肌肉复合动作电位）的变化相对较小。3. 在疲劳期间使用H（霍夫曼）反射测试比目鱼肌运动神经元的兴奋性时，发现其显著降低。缺血或电刺激但无疲劳的对照实验未能显示对反射兴奋性有任何显著影响。4. 本研究中的发现支持疲劳期间α运动神经元反射抑制的概念。

Reflex inhibition of human soleus muscle during fatigue.