Evaluate the importance of different fuel sources and their efficiency of ATP production for athletes competing in different duration events. (8 marks)
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Sample Answer
Evaluation Statement
- Fuel source selection and ATP production efficiency fundamentally determine athletic performance across different event durations.
- Evaluation based on: fuel availability, ATP yield efficiency, and event-specific demands.
Short Duration Events (10-15 seconds)
- Phosphocreatine provides the only fuel source for explosive efforts like shot put or 100m sprint starts.
- This system produces ATP most rapidly, enabling maximum power output immediately.
- However, limited PCr stores exhaust within seconds, making it unsuitable for longer efforts.
- The trade-off between speed and capacity proves ideal for brief maximal performances.
Medium Duration Events (30 seconds – 2 minutes)
- Glucose becomes the primary fuel through anaerobic breakdown during 400m runs or 100m swims.
- This produces ATP quickly but inefficiently, with only partial glucose breakdown occurring.
- Lactic acid accumulation limits duration despite adequate glucose availability.
- Athletes must balance intensity against rapidly increasing fatigue from metabolic by-products.
Long Duration Events (over 3 minutes)
- Both carbohydrates and fats fuel aerobic metabolism in marathons and distance cycling.
- Complete fuel oxidation yields far more ATP per glucose molecule than anaerobic systems.
- Fat provides virtually unlimited energy but requires more oxygen per ATP produced.
- Efficiency allows sustained performance though at lower intensities than anaerobic metabolism permits.
Final Evaluation
- Event duration dictates optimal fuel source selection more than any other factor.
- ATP production efficiency inversely relates to production speed across all systems.
- Athletes cannot choose their fuel source; duration and intensity determine it automatically.
- Understanding these relationships helps athletes pace efforts appropriately for their event.
Show Worked Solution
Sample Answer
Evaluation Statement
- Fuel source selection and ATP production efficiency fundamentally determine athletic performance across different event durations.
- Evaluation based on: fuel availability, ATP yield efficiency, and event-specific demands.
Short Duration Events (10-15 seconds)
- Phosphocreatine provides the only fuel source for explosive efforts like shot put or 100m sprint starts.
- This system produces ATP most rapidly, enabling maximum power output immediately.
- However, limited PCr stores exhaust within seconds, making it unsuitable for longer efforts.
- The trade-off between speed and capacity proves ideal for brief maximal performances.
Medium Duration Events (30 seconds – 2 minutes)
- Glucose becomes the primary fuel through anaerobic breakdown during 400m runs or 100m swims.
- This produces ATP quickly but inefficiently, with only partial glucose breakdown occurring.
- Lactic acid accumulation limits duration despite adequate glucose availability.
- Athletes must balance intensity against rapidly increasing fatigue from metabolic by-products.
Long Duration Events (over 3 minutes)
- Both carbohydrates and fats fuel aerobic metabolism in marathons and distance cycling.
- Complete fuel oxidation yields far more ATP per glucose molecule than anaerobic systems.
- Fat provides virtually unlimited energy but requires more oxygen per ATP produced.
- Efficiency allows sustained performance though at lower intensities than anaerobic metabolism permits.
Final Evaluation
- Event duration dictates optimal fuel source selection more than any other factor.
- ATP production efficiency inversely relates to production speed across all systems.
- Athletes cannot choose their fuel source; duration and intensity determine it automatically.
- Understanding these relationships helps athletes pace efforts appropriately for their event.