摘要：Costa PNC, Musialowski R, Palma A. Central and Peripheral Fatigue in Physical Effort: A Mini-Review. JEPonline 2019;22(5):220-226. Fatigue is considered to be a defensive mechanism of the organism, as a means to preserve the neuromuscular system when facing intense physical effort situations, reducing the capacity of producing force. However, there is evidence of peripheral mechanisms, pointing to changes in the neuromuscular junction and the muscle fiber membrane (sarcolemma) that lead to a marked decrease in the mechanisms of ATP production, which to a certain extent hinders the connection between myosin and actin. The result is a type of fatigue, together with the combined accumulation of muscle metabolite sub-products such as extracellular K+, H+, ADP, Pi ions, Mg+, and La-, as well as the formation of reactive oxygen species, the decrease in the resting potential of the membrane, and the ATP and PC production plus changes in the calcium pump of the sarcoplasmic reticulum. When a central fatigue is detected, there are neuromuscular junction faults as a result of the neural signal alteration that reaches the muscle, as well as other aspects, such as: increased K+, H+, inorganic phosphate, bradykinin, prostaglandin, ammonia, and decreased plasma glucose, muscle and liver glycogen, hyperemia, plasma tryptophan and 5-hydroxytryptophan. However, the motivation reduction, pain tolerance, deficit of reasoning and attention, decreased peripheral motor coordination, central nervous structures, transmission of electrical impulses from the spinalcord to the motor nerves and motor neuron recruitment are also considered as indicators ofcentral fatigue. These factors depend on the intensity, frequency, duration, types ofexercises, locations where the exercises are performed, environmental factors, and levels ofindividual physiological conditioning and biochemical adaptations. Coaches and athletesshould adjust their athletes’ training loads and nutritional aspects to minimize the deleteriouseffects of fatigue to obtain performance improvement.
