Alterations of neuromuscular function after an ultramarathon

Groupe Analyse du Mouvement, Faculté des Sciences du Sport, Université de Bourgogne, 21078 Dijon Cedex, France Neuromuscular fatigue of the knee extensor (KE) and plantar flexor (PF) muscles was characterized after a 65-km ultramarathon race in nine well-trained runners by stimulating the femoral and tibial nerves, respectively. One week before and immediately after the ultramarathon, maximal twitches were elicited from the relaxed KE and PF. Electrically evoked superimposed twitches of the KE were also elicited during maximal voluntary contractions (MVCs) to determine maximal voluntary activation. MVC and maximal voluntary activation decreased significantly after the ultramarathon ( 30.2 ± 18.0% and 27.7 ± 13.0%, respectively; P