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?
a) During heavy exercise like running a deficiency of oxygen is created in the muscle cells. This deficiency leads to anaerobic respiration in the muscle cells. During anaerobic respiration glucose which is present in the muscle cells breaks down into lactic acid which gets accumulated in the muscle cells of the legs thus causing pain and cramps.
b) While massaging, the flow of blood in the blood vessels (circulation) increases thus increasing the oxygen supply to the muscle cells. The proper supply of oxygen leads to complete breakdown of glucose.