# Explain why athletes who sprint a 100 m race continue to breathe rapidly for several minutes after they cross the finish line, even though the race is over.

> Pearson Edexcel International GCSE Biology (4BI1) — 2.7 Respiration · Explain · 4 marks

> During a 100 m sprint, muscle cells respire anaerobically as well as aerobically. After the race, the athletes stop running but their breathing rate remains elevated for some time.

## Mark scheme (4 marks)

1. During the sprint, muscles respired anaerobically and produced lactic acid
2. After the race, extra oxygen is needed to break down / oxidise the lactic acid
3. This extra oxygen required is called the oxygen debt
4. Rapid breathing allows more oxygen to be taken in / delivered to tissues to repay the oxygen debt

## Related

- [Revision notes for Pearson Edexcel International GCSE Biology (4BI1)](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

---
Source: [GradeNine](https://www.gradenine.co.uk/q/explain-why-athletes-who-sprint-a-351578e5) · Published by Druglandscape Ltd.