During intense exercise, muscle fatigue can lead to force production failure. Which mechanism explains why cross-bridge cycling ceases when intracellular conditions reach a critical state?

💡 Explanation

During intense exercise, inorganic phosphate (Pi) accumulates due to ATP hydrolysis. Elevated Pi directly inhibits the myosin ATPase activity, thus preventing cross-bridge cycling because the energy needed for the power stroke is absent; therefore, the mechanism of force production failure is Pi accumulation, rather than glycogenolysis, NADH accumulation or a calcium imbalance.

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