Neuromuscular Fatigue During Brazilian Jiujitsu Matches: Analysis of Upper and Lower Limbs

Purpose: To determine the effects of repeated Brazilian jiujitsu (BJJ) matches on neuromuscular fatigue in forearm- fl exor and knee-extensor muscles. Methods: Twelve BJJ athletes (8 men and 4 women) performed a simulated BJJ tournament composed of four 8-minute matches interspersed by 16-minute intervals. Neuromuscular fatigue was assessed via prematch to postmatch(es) reductions in maximal voluntary isometric contraction (MVIC), voluntary activation, and potentiated twitch force (Ptw pot ) in the forearm- fl exor and knee-extensor muscles. Results: The MVIC of the knee extensors and forearm fl exors reduced from prematch 1 to postmatch 2 and remained suppressed until postmatch 4 ( P < .034). The voluntary activation of the knee extensors declined only after match 4, whereas the voluntary activation of the forearm fl exors did not change throughout the matches ( P = .102). Ptw pot of knee extensors decreased from prematch 1 to postmatch 1 ( P < .001) and remained reduced until postmatch 4 ( P < .001). Ptw pot of the forearm fl exors reduced after every match ( P < .010), with complete recovery occurring only before the second match ( P = .99). The magnitude of the prematch-to-postmatch reduction in Ptw pot was lower in knee extensors than in forearm fl exors ( P = .044). Conclusions: Repeated BJJ matches induced neuromuscular fatigue, mainly due to impairments in muscle contractile function (ie, peripheral fatigue). The time between BJJ matches seems to be insuf fi cient to allow complete recovery of neuromuscular function, which may in fl uence performance during subsequent matches.