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?
Answers
(a)Most probable reason for pain and cramps in her legs is the accumulation of lactic acid.
During rigorous exercise, breathing is not able to meet the oxygen demands of all the body parts. The oxygen obtained by breathing will be first supplied to essential organs and then to other organs. In such a case, there is not sufficient oxygen for the muscles to break down glucose aerobically and carry out aerobic respiration. To meet the energy demand of the exercising muscles, anaerobic respiration is carried out. This results in the formation and accumulation of lactic acid in the muscles. Lactic acid can cause cramps.
(b) When the legs are massaged, the pain is relieved as the lactic acid accumulated is burnt.
During massaging, the blood supply is increased and this increased the amount of oxygen coming to the leg muscles. This oxygen is used to burn out the lactic acid. She feels better as the lactic acid is no more present.