Exemplar Problems

Question 5

What factors contribute to muscle fatigue during prolonged physical activities?

Solution: Muscle fatigue during prolonged activities is influenced by several factors. The primary factor is the accumulation of lactic acid, a byproduct of anaerobic respiration, which can interfere with muscle contraction mechanisms. Additionally, ion imbalances, particularly involving calcium and potassium ions, can disrupt the electrical gradients necessary for muscle contraction. Furthermore, prolonged exertion leads to the depletion of energy reserves, like glycogen, and reduced levels of ATP, hindering the muscle’s ability to contract effectively. These factors combined result in decreased muscle strength and endurance, manifesting as muscle fatigue.