Explain how the three energy systems interplay during a 400 m sprint race. (6 marks)
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Sample Answer
- First 10 seconds: ATP-PCr system dominates providing immediate energy for explosive start
- 10-30 seconds: Glycolytic system becomes predominant as ATP-PCr depletes
- 30-60 seconds: Continued dominance of glycolytic system with increasing aerobic contribution
- Systems operate simultaneously but with varying contributions throughout race
- Accumulation of lactic acid leads to fatigue in final stages
- Recovery requires replenishment of ATP-PCr stores and removal of lactic acid
Show Worked Solution
Sample Answer
- First 10 seconds: ATP-PCr system dominates providing immediate energy for explosive start
- 10-30 seconds: Glycolytic system becomes predominant as ATP-PCr depletes
- 30-60 seconds: Continued dominance of glycolytic system with increasing aerobic contribution
- Systems operate simultaneously but with varying contributions throughout race
- Accumulation of lactic acid leads to fatigue in final stages
- Recovery requires replenishment of ATP-PCr stores and removal of lactic acid