Modulation of motor unit discharge rate and H-reflex amplitude during submaximal fatigue of the human soleus muscle

摘要: Declining motor unit discharge rates and H-reflex amplitude have been observed in separate experiments during fatiguing submaximal contractions humans. The purpose of this experiment was to investigate rate, amplitude, twitch contractile properties concurrently a isometric contraction the ankle plantarflexors. Eleven healthy subjects performed low force (25% maximal voluntary (MVC)) or high (42–66% MVC). Hoffmann (H)-reflexes, muscle compound action potentials (M-waves), properties, discharges were recorded from soleus muscle. In low-force fatigue task, firing rate increased gradually over time, whereas resting significantly depressed at 15% endurance time remained quasiconstant for rest task. This suggests that processes mediating depression are relatively independent those modulating high-force decline average accompanied by decrease prolongation half-relaxation (HRT) completion Overall, modulated parallel with changes HRT, consistent wisdom hypothesis.