MICROANATOMY

Detailed explanation-1: -Fatigue often develops when substrates for ATP generation are depleted and/or when metabolic by-products accumulate in contracting muscle and the blood. Reductions in intramuscular levels of ATP, phosphocreatine and glycogen, and low blood glucose (hypoglycemia) can impair skeletal muscle performance.

Detailed explanation-2: -Depletion of required substrates such as ATP or glycogen within a muscle result in fatigue as the muscle is not able to generate energy to power contractions.

Detailed explanation-3: -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.

Detailed explanation-4: -Fatigue develops rapidly during physical activities requiring a rate of ATP production that exceeds the aerobic capacity of the muscle fibers. Thus, this type of fatigue is closely related to the need for ATP produced by anaerobic metabolism.