An elite marathon runner experiences a sudden decrease in performance despite maintaining pace. Which failure mode involving metabolic byproducts becomes likely when energy demand exceeds muscle clearance capacity?

💡 Explanation

Intense exercise can lead to the accumulation of hydrogen ions within muscle tissue, inhibiting glycolysis and ATP production, because the rate of production surpasses removal. Therefore, muscle fatigue is accelerated rather than reversed by enhanced buffering or oxidative capacity.

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