During a marathon, a runner's leg muscles experience failure despite sufficient oxygen. Why does this muscle failure occur when ATP supply cannot meet demand?

💡 Explanation

Muscle failure occurs because ATP depletion reduces the cross-bridge detachment rate. The myosin head remains attached to actin longer, slowing contraction cycles, and ultimately leading to muscle fatigue; therefore, detachment failure occurs, rather than simple neurotransmitter failure or calcium depletion.

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