Question

After undeegoing sternous exercise we feel pain in muscles does adequate.oxygen reach the muscles

Answer 1

At the time of doing heavy exercise, oxygen don't reaches the muscles of the boat and hence makes the muscles cells to perform anaerobic respiration. This results to the formation of lactic acid there. This causes cramp. This caused cramp only results to the pain.

Answer 2

Sometimes, during strenous exercise, the demand of oxygen in the muscles increases, but the heart is unable to provide enough oxygen. Therefore, to generate energy, the muscles respire in the absence of oxygen (anaerobically) which breaks down glucose into lactic acid. But this lactic acid can slowly poison our muscles and can cause cramps (severe muscle pain). To get rid of these cramps, we respire deeply so that the inhaled oxygen breaks down lactic acid.

Hope this helps :)