Explain how causes of fatigue differ between the ATP-PCr system and the glycolytic system during high-intensity exercise. (4 marks)
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- The ATP-PCr system experiences fatigue solely from phosphocreatine depletion after 10-15 seconds of maximal effort.
- This occurs because stored PCr becomes exhausted without producing any fatiguing by-products.
- Heat is the only by-product, which enables rapid recovery within 2 minutes.
- Therefore, ATP-PCr fatigue is temporary and quickly reversible.
- The glycolytic system fatigues due to lactic acid accumulation in muscle cells.
- Lactic acid forms when glucose breaks down anaerobically, accumulating faster than removal rates.
- As a result, the acid interferes with enzyme function and muscle contraction.
- Consequently, glycolytic fatigue persists longer, requiring 30-60 minutes for complete recovery.
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Sample Answer
- The ATP-PCr system experiences fatigue solely from phosphocreatine depletion after 10-15 seconds of maximal effort.
- This occurs because stored PCr becomes exhausted without producing any fatiguing by-products.
- Heat is the only by-product, which enables rapid recovery within 2 minutes.
- Therefore, ATP-PCr fatigue is temporary and quickly reversible.
- The glycolytic system fatigues due to lactic acid accumulation in muscle cells.
- Lactic acid forms when glucose breaks down anaerobically, accumulating faster than removal rates.
- As a result, the acid interferes with enzyme function and muscle contraction.
- Consequently, glycolytic fatigue persists longer, requiring 30-60 minutes for complete recovery.