Sports · 2
What physiological cause forces marathon runners to suddenly slow down when they 'hit the wall'?
Answer
Glycogen depletion
When a marathon runner's stored glycogen — the body's primary carbohydrate fuel — is exhausted around mile 20, muscles must abruptly shift to burning fat, which is a less efficient energy source. This sudden transition causes the dramatic slowdown known as 'hitting the wall.'
💡 Did you know?
Marathon runners experience 'hitting the wall' around mile 20 because glycogen depletion forces muscles to switch energy sources suddenly.
Other options people guess
- Severe dehydration
- Lactic acid buildup
- Potassium deficiency
Topics
- marathon
- running
- endurance
- physiology
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