A stretching calf cramps, due to the following reasons: First, due to prolonged non-exercise, many patients sit and stand for a long time, do not exercise, this will lead to disuse atrophy of the calf muscles, will make the calf muscles muscle strength to a large extent decreased. Patients stretching process, the whole body muscles will be in a certain period of time to maintain a relatively tense state, the calf part of the muscle will be due to long-term tension and spasm. Second, due to poor posture, many patients in sitting and standing, often habitually tiptoe. This process will keep the calf muscles tense for a long time, and then there is a tendency for spasms to occur. If the patient stands up and stretches, a sudden cramp in the calf may occur. Third, as a result of sciatica, the attack of this type of disease will often have severe pain in the lower limbs, and the patient will have the habit of keeping the lower limbs contracted and curled up. At this time, if the patient stretches, in the process of straightening the lower limb, it will pull the sciatic nerve, and then induce severe pain in the lower limb, which can also cause calf cramps.