Muscle soreness tends to develop 24-48 hours after physical activity, especially if you’ve been using your body in ways it’s not used to. This, counter to popular belief, is not caused by a buildup of lactic acid, but microscopic tears in muscle tissue. Any time the body flexes a muscle and also puts pressure on it- such as jogging on concrete or the impact of a punching bag, tiny tears appear. This is not a bad thing, as every time the body rebuilds itself it makes the muscl