Describe how fuel sources contribute to fatigue during the final stretch of a 400-metre race. (3 marks)
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Sample Answer
- The 400m relies heavily on the glycolytic system which uses glucose as fuel for the final stretch.
- This system produces ATP quickly but creates lactic acid as a by-product.
- Lactic acid builds up rapidly in muscles, making them increasingly acidic and reducing their ability to contract.
- Additionally, the intense effort uses up muscle glucose stores quickly.
- These combined effects cause severe fatigue, forcing runners to slow dramatically in the final metres.
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Sample Answer
- The 400m relies heavily on the glycolytic system which uses glucose as fuel for the final stretch.
- This system produces ATP quickly but creates lactic acid as a by-product.
- Lactic acid builds up rapidly in muscles, making them increasingly acidic and reducing their ability to contract.
- Additionally, the intense effort uses up muscle glucose stores quickly.
- These combined effects cause severe fatigue, forcing runners to slow dramatically in the final metres.