Overuse or injuries are common causes for painful muscle contractions, which can involve neck, chest, back, abdominal, calf, and front & back thigh muscles, and they can be experienced in one's hands, arms, and toes. After stretching and massaging the affected muscle, consuming foods or beverages containing Lactic Acid is one strategy to reduce muscle tension when working out, despite the buildup of lactic acid in muscle tissue during strenuous exercise being actually a common cause of muscle cramps. This happens from insufficient oxygen not being able to oxidize lactic acid, which would otherwise get rid of it from muscle... Full Text