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. (a) What can be the possible reasons for the pain in her legs? (b) Why did she feel comfortable after a massage?
ScienceClass 7CBSEAnswered 27 Mar 2026
Answer
Soln:
a) Pain in her legs might be because of the accumulation of lactic acid in her muscles. During heavy physical activity muscle, cells respire anaerobically, producing lactic acid.
b) The massage gave her relief because it improves the circulation of blood, leading to an increased supply of oxygen
to the muscle cells, which helps the incomplete breakdown of lactic acid into CO2 and water.
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