Raju Sharma, a 10th standard student participated in 100 meter sprint. During running he developed painful muscle contraction and fell down. The physical education teacher rushed to him and gave a hot water massage. Raju Sharma slowly recovered from the cramp. Identify the right explanation.

Because of the quick movement, the muscles lose their elasticity and are stressed. The inflammation developed during this process causes cramp. After hot water massage the inflammation subsides and the pain gets relieved.

During vigorous physical activity, aerobic respiration in the muscles increases which leads to the accumulation of more $$\mathrm{CO_2}$$ in the muscles. This causes cramps. Later $$\mathrm{CO_2}$$ was relieved upon hot water massage resulting in pain relief.

During vigorous physical activity, lactic acid accumulates in the muscles due to anaerobic respiration. This causes the cramps. Hot water massage improves the circulation of blood and $$\mathrm{O_2}$$ in the muscles. As a result lactic acid is converted into $$\mathrm{CO_2}$$ and water. Thus the pain gets relieved.

During quick movements, the nerves will not co-operate with the muscles. There is a stimulus which is taken to spinal cord and the effector function was done by motor neurons which cause cramp. On hot water massage the stimulus was subsided. Thus the pain gets relieved.