Muscle fatigue occurs due to
All of the above
Substrate shortage is one of the causes of metabolic fatigue. Substrates are depleted during exercise, resulting in a lack of intracellular energy sources for muscle contractions. In essence, the muscle stops contracting because it lacks the energy to do so.
Fatigue is a feeling of tiredness or exhaustion or a need to rest because of lack of energy or strength. Fatigue may result from overwork, poor sleep, worry, boredom, or lack of exercise.