what is happening when your muscle burns
When you exercise and isolate a muscle group, lactic acid, produced naturally by your body, begins to build around that muscle. As the lactic acid surround the muscle, it results in a burning sensation. While the burn is often associated with becoming stronger, the feeling of heat and fatigue often ends your workout. After a certain number of repetitions, the lactic acid causes muscle fatigue as it interacts in the calcium in your body.