Muscle fatigue: what, why and how it influences muscle function

Abstract

Much is known about the physiological impairments that can cause muscle fatigue. It is known that fatigue can be caused by many different mechanisms, ranging from the accumulation of metabolites within muscle fibres to the generation of an inadequate motor command in the motor cortex, and that there is no global mechanism responsible for muscle fatigue. Rather, the mechanisms that cause fatigue are specific to the task being performed. The development of muscle fatigue is typically quantified as a decline in the maximal force or power capacity of muscle, which means that submaximal contractions can be sustained after the onset of muscle fatigue. There is even evidence that the duration of some sustained tasks is not limited by fatigue of the principal muscles. Here we review experimental approaches that focus on identifying the mechanisms that limit task failure rather than those that cause muscle fatigue. Selected comparisons of tasks, groups of individuals and interventions with the task-failure approach can provide insight into the rate-limiting adjustments that constrain muscle function during fatiguing contractions.

El acoplamiento excitación-contracción en el músculo esquelético: preguntas por responder a pesar de 50 años de estudio

“…La fatiga muscular se define como la dificultad para mantener el rendimiento o trabajo muscular en términos de potencia (fuerza y velocidad), esperado o requerido (86)(87)(88).…”

“…El mecanismo fisiológico que explica el fenómeno de la fatiga del músculo esquelético no está claro y el tema se sigue considerando controversial; se han propuesto varias hipótesis para explicarlo (86)(87)(88)90), la mayoría relacionadas con alteraciones del mecanismo de acoplamiento excitación-contracción.…”

Fatores clínicos, funcionais e inflamatórios associados à fadiga muscular e à fadiga autopercebida em idosas da comunidade

“…Muscle fatigue can be defined as the reduction, induced by the capacity of the neuromuscular system to generate strength, work or power 1,3,4 . Its setup may be related to neurological, metabolic, electrophysiological, mechanical, subjective among others, which interfere in the synchronous functioning between the central nervous system (CNS) and the peripheral paths 5,6 .…”

Comparação de protocolos de corrida para determinação de diferentes limiares

“…Particularmente, grande atenção pode ser observada com relação à fadiga muscular, pois a melhor compreensão deste fenômeno possibilita maior controle sobre o risco do surgimento de lesões e melhor direcionamento das estratégias de treinamento. A fadiga muscular é caracterizada por uma gradual redução na capacidade de produção de força, que pode ser associada a alterações na atividade eletromiográfica ou à exaustão da função contrátil 1 .…”