Enhanced availability of serotonin limits muscle activation during high-intensity, but not low-intensity, fatiguing contractions

Abstract

As serotonin release onto motoneurons may be scaled to the strength of muscle contraction, it may have different effects when neuromuscular fatigue is induced by contractions of different intensities. Enhanced levels of serotonin compromised voluntary activation of muscle when fatigue was induced by strong contractions but not weak contractions. This provides evidence that the serotonergic system has the greatest influence on fatigue that is generated with high neural drive to the target muscle.