It is well known that unaccustomed eccentric exercise leads to delayed onset muscle soreness (DOMS), which can produce long-lasting effects on muscle function. Indicators in maximal voluntary isokinetic concentric contraction, muscle soreness, the range of motion, and surface electromyography (EMG). Repeated bout effect (RBE) is a phenomenon reported in studies where there is a decrease in the muscle damage of limbs that performed lengthening contractions following eccentric exercise in the trained limbs. The purpose of this review is to highlight the effect of neural factors of maximal isometric contractions at lengthening angle on the activation of muscle following maximal isokinetic eccentric contractions of the lower limbs by examining the change in motor unit activity obtained from EMG. We will review the mechanism that underlies the RBE with special emphasis on (1) muscle damage induced by eccentric exercise, (2) the role of RBE on eccentric exercise, (3) the role of surface EMG activity on RBE, and (4) general summary and conclusions. Future, studies should focus on establishing if maximal voluntary isometric contraction (MVC) protect other populations (i.e., trained people) or muscle groups (i.e., knee flexors) against exercise-induced muscle damage (EIMD), as well as investigate different mechanisms for MVC induced protection.
延遲性肌肉酸痛是因為離心運動後,作用肌群有明顯的肌肉酸痛現象,也是運動引起肌肉細微損傷典型的間接評估指標之一;其他常見間接評估指標,計有:肌力與肌肉收縮速率短暫下降、引起肌肉腫脹與僵硬、關節活動範圍減少、肌肉收縮時肌電訊號之平均數功率頻率下降、以及運動單元電位的徵招與傳導速率下降。預先進行離心運動所產生的保護適應現象,稱為重複訓練效應。本篇針對下肢等長運動後的保護效果,其表層肌電訊號反應進行回顧探討,依研究相關性分為四部分:離心收縮與肌肉損傷、離心收縮與保護效果、保護效果與表層肌電訊號、結語。未來可針對不同族群、肌群,探討預先等長運動對離心運動造成肌肉損傷的保護效果,以及潛在的機制。