Gastrocnemius spasm, or “calf cramp”. It is the most common type of painful spasm, characterized by a sudden onset of tonic painful spasm of the gastrocnemius muscle, pulling and twisting, lasting from tens of seconds to several minutes or more, and the pain is indescribable. Many friends will have this experience: turn over or stretch your legs in the middle of the night, you will cramp. The pain is unbearable, especially in the middle of the night when the cramp often wakes people up in pain, and the pain does not stop for a long time and affects their sleep. Slightly more serious, by the next day will be a little sore, uncomfortable feeling, and if it occurs once, it will occur frequently during that time. So what the heck is going on here! Gastrocnemius cramp causes Many people think that leg cramps are due to a lack of calcium and can be treated with a little calcium supplement. In fact, when sleeping, calf cramps are caused by various reasons, not only because of calcium deficiency. 1, sleep cold Inadequate preparation for exercise in a cold environment, or swimming in the summer water temperature is low, are likely to cause leg cramps. Sleeping at night without covers, the calf muscles are stimulated by the cold and will spasm so much that it hurts to wake up. 2, continuous muscle contraction too fast When strenuous exercise, the whole body is in a state of tension, the leg muscles contract too fast, the relaxation time is too short, the local metabolites lactic acid increased, the muscle contraction and relaxation is difficult to coordinate, thus causing calf muscle cramps. 3, metabolism problems When the exercise time is long, and the amount of exercise, sweating and more, and no timely replenishment of salt, the body lost a lot of fluid and electrolytes, resulting in the accumulation of metabolic waste. Poor local blood circulation in the muscles, prone to spasm. 4, excessive fatigue climbing, climbing, calf muscle fatigue is most likely to occur. Because it is a foot to support the weight of the whole body, the force required to lift the leg muscles will be six times the weight of the person, when it is fatigued to a certain extent, spasm will occur. 5, lack of calcium calcium ions play an important role in the process of muscle contraction. When the concentration of calcium ions in the blood is too low, the muscle is easily excited and spasms. Adolescents are growing rapidly and are prone to calcium deficiency, so leg cramps often occur. 6, poor sleep posture, such as prolonged supine, so that the quilt pressed on the feet, or prolonged prone, so that the feet against the bed, forcing some muscles in the calf for a long time in absolute relaxation, causing muscle “passive contracture”.