MEDICAL PHYSIOLOGY

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: -Muscle fatigue has a number of possible causes including impaired blood flow, ion imbalance within the muscle, nervous fatigue, loss of desire to continue, and most importantly, the accumulation of lactic acid in the muscle.

Detailed explanation-3: -Glycolysis converts glucose to pyruvate, water and NADH, producing two molecules of ATP. Excess pyruvate is converted to lactic acid which causes muscle fatigue.

Detailed explanation-4: -By definition, a muscle begins to experience fatigue as soon as its maximal force or power capacity starts to decline. When the task involves sustaining a maximal contraction, the decline in performance parallels the increase in fatigue.