Anti-fatigue action exerted by the sympathetic nervous system in the rabbit digastric muscle.

Stimulation of the cervical sympathetic trunk, at frequencies within the physiological range, consistently elicits a partial recovery of the contractile force in the fatigued digastric muscle. This action, together with the tension potentiation induced by the sympathetic system in the non-fatigued muscle, could improve the muscular performance under the physiological conditions associated with increase in the sympathetic outflow.