Outline TWO causes of fatigue when an athlete performs a 100 metre sprint. (3 marks)
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Sample Answer
Any 2 of the following
- Phosphocreatine stores run out within 10 seconds of maximal sprinting. This means the ATP-PCr system cannot make enough ATP for explosive movements, forcing the body to use slower energy systems and causing speed to drop.
- Neural fatigue happens when fast-twitch muscle fibres work continuously. The brain and nerves cannot keep sending strong signals throughout the sprint, so muscles produce less force even when in the final metres.
- Lactic acid builds up as the glycolytic system works near the sprint’s end. This makes muscles more acidic and prevents them contracting properly in the final metres, causing runners to slow down at the finish.
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Sample Answer
Any 2 of the following
- Phosphocreatine stores run out within 10 seconds of maximal sprinting. This means the ATP-PCr system cannot make enough ATP for explosive movements, forcing the body to use slower energy systems and causing speed to drop.
- Neural fatigue happens when fast-twitch muscle fibres work continuously. The brain and nerves cannot keep sending strong signals throughout the sprint, so muscles produce less force even when in the final metres.
- Lactic acid builds up as the glycolytic system works near the sprint’s end. This makes muscles more acidic and prevents them contracting properly in the final metres, causing runners to slow down at the finish.