Question

Paheli participated in a 400 m race competition held at her school and won the race. When she came home she had mixed feelings of joy and pain as she had cramps in her leg muscles. After a massage, she was relieved of the pain. Answer the following questions related to the situation. [2 marks]

(a) What can be the possible reasons for the pain in her legs?

(b) Why did she feel comfortable after a massage?

Answer 1

(a)

• The possible reasons for the pain in her legs can be due to the accumulation of lactic acid in the muscles.

(0.5 marks)

• During heavy exercise or running, etc., the muscle cells respire anaerobically and produce lactic acid, which is an incomplete breakdown of glucose.

(0.5 marks)

(b)

• The massage gave her relief because it improved the circulation of blood.

(0.5 marks)

• This lead to an increased supply of oxygen to the muscle cells which helped in a complete breakdown of lactic acid into $C{O}_2$ and water. ​​​​​​

(0.5 marks)