Cramps occur in leg extension, often including the following two aspects: first, leg cramps are caused by hypocalcemia, hyperkalemia, and osteoporosis and other diseases in the body, or the environmental temperature is too low resulting in muscle stress, these factors can lead to painful spasms in the legs, that is, cramps; second, the leg is suddenly straightened, the gastrocnemius muscle caused by a short period of sudden pull, can stimulate the gastrocnemius muscle to occur painful Therefore, we should pay attention to keep the calcium and potassium ions in the internal environment stable, prevent osteoporosis, prevent the legs from getting cold, and move slowly when stretching the legs, not too fast and too strongly, which can prevent cramps.