Question

Paheli participated in a 400m 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.​ ​
(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) During heavy exercise, a deficiency of oxygen is created in the muscle cells. This deficiency leads to anaerobic respiration in the muscle cells, where partial breakdown of glucose produces lactic acid.


Lactic acid gets accumulated in the muscle cells causing cramps.​

(b) While massaging, the flow of blood in the blood vessels increases thus increasing the oxygen supply to the muscle cells. The proper supply of oxygen leads to complete breakdown of lactic acid into water and carbon dioxide.​ This relieves the pain.