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HMS, BM 2025 HSC 19 MC

During a training session, a runner completes 40 m high intensity sprints with a 2 minute recovery period between each.

Which of the following explains the runner's rate of recovery and the efficiency of ATP production during the recovery periods between sprints?

  1. The lactic acid system is responsible for recovery, leading to the production of lactate and slower resynthesis of ATP.
  2. The ATP-PCr system is quickly replenishing phosphocreatine stores, allowing for a fast recovery and efficient ATP production.
  3. The lactic acid system is primarily used during recovery, allowing for efficient ATP production, but it takes several minutes to recover.
  4. The ATP-PCr system is slower to replenish phosphocreatine stores, leading to inefficient ATP production and more time is needed to recover.
Show Answers Only

\(B\)

Show Worked Solution

  • B is correct: Alactacid system rapidly restores phosphocreatine stores within 2-3 minutes, enabling quick ATP resynthesis between sprints

Other Options:

  • A is incorrect: Lactic acid system produces lactate during work, not recovery; recovery removes lactate, doesn’t produce it
  • C is incorrect: Lactic acid system creates ATP during exercise, not recovery; recovery period removes accumulated lactate
  • D is incorrect: Alactacid system replenishes quickly (50% in 30 seconds, 100% in 2-3 minutes), not slowly