Final answer:
Muscle fatigue is connected to cellular respiration through ATP production and the management of lactic acid; insufficient oxygen during vigorous exercise causes a switch to anaerobic glycolysis, building lactic acid which may lead to fatigue.
Step-by-step explanation:
The relationship between muscle fatigue and cellular respiration lies primarily in the muscles' capacity to produce ATP and manage by-products of energy production like lactic acid. When muscles are engaged in strenuous exercise, the demand for ATP surpasses the oxygen supply needed for aerobic respiration. In the absence of sufficient oxygen, muscles revert to anaerobic glycolysis, producing ATP along with lactic acid, which can lead to muscle fatigue.
This is because lactic acid lowers the intracellular pH, which adversely affects enzymes and proteins, potentially impairing muscular function. Furthermore, during sustained muscular activity, ATP can be depleted, and the energy to contract muscles diminishes, leading to fatigue.