Final answer:
Fatigue factors are categorized as metabolic, like exhaustion of ATP energy reserves and lactic acid buildup, and electrolyte imbalance, such as the disruption of Na+ and K+ levels. These contribute to a decrease in muscle contraction capability.
Step-by-step explanation:
Factors contributing to fatigue can be categorized into metabolic and electrolyte imbalance factors. An example of a metabolic factor is the exhaustion of energy reserves, where the body consumes available ATP (adenosine triphosphate) during high-intensity physical activities like sprinting. Lactic acid buildup is another metabolic factor that occurs due to anaerobic respiration in muscles during strenuous exercises, leading to a decrease in intracellular pH. On the other hand, an electrolyte imbalance, such as changes in Na+ and K+ levels, can affect the muscle membrane potential and interrupt normal Ca++ flow, which is essential for muscle contraction.
These two categories of factors play significant roles in diminishing the muscle's ability to sustain contractions, thus leading to fatigue. As ATP reserves decline or as Na+ and K+ levels become imbalanced, muscles become less capable of maintaining prolonged activity.