A sprinter is positioned in the starting blocks of a 100-metre race.
Explain how the nervous, muscular and circulatory systems work together from the "on your marks" command to the first few seconds of the race. (5 marks)
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Sample Answer
“On your marks” phase:
- The nervous system heightens alertness and prepares motor pathways for action.
- This causes heart rate to begin increasing through nerve signals to the heart.
- As a result, the circulatory system prepares to deliver more oxygen to muscles.
“Set” position:
- Nerve signals activate muscles to create tension in legs and arms.
- This muscle tension enables explosive force production when the gun fires.
- Meanwhile, blood flow increases to leg muscles through vasodilation.
- This increased blood flow ensures muscles have oxygen for immediate use.
Gun fired – first seconds:
- The nervous system sends rapid signals to leg muscles.
- These signals trigger powerful muscle contractions in quadriceps and glutes.
- Consequently, the sprinter drives forcefully off the blocks.
- Heart rate increases rapidly because muscles demand more oxygen.
- This coordination between all three systems produces maximum acceleration.
System integration:
- The interaction shows how nerve signals control both muscle action and heart response.
- While the nervous system coordinates movement, the circulatory system supports energy needs.
- Therefore, successful sprint starts require all three systems working together instantly.
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Sample Answer
“On your marks” phase:
- The nervous system heightens alertness and prepares motor pathways for action.
- This causes heart rate to begin increasing through nerve signals to the heart.
- As a result, the circulatory system prepares to deliver more oxygen to muscles.
“Set” position:
- Nerve signals activate muscles to create tension in legs and arms.
- This muscle tension enables explosive force production when the gun fires.
- Meanwhile, blood flow increases to leg muscles through vasodilation.
- This increased blood flow ensures muscles have oxygen for immediate use.
Gun fired – first seconds:
- The nervous system sends rapid signals to leg muscles.
- These signals trigger powerful muscle contractions in quadriceps and glutes.
- Consequently, the sprinter drives forcefully off the blocks.
- Heart rate increases rapidly because muscles demand more oxygen.
- This coordination between all three systems produces maximum acceleration.
System integration:
- The interaction shows how nerve signals control both muscle action and heart response.
- While the nervous system coordinates movement, the circulatory system supports energy needs.
- Therefore, successful sprint starts require all three systems working together instantly.