A morning leg stretching calf belly cramps may be caused by the following reasons: 1, there may be disuse muscle atrophy, often seen in patients due to the existence of trauma to the lower limbs, or for other reasons need to be bedridden for a long time, resulting in the muscles of the lower limbs do not get enough exercise, followed by disuse muscle atrophy. The first is the contracture of the muscle itself, and the second is a significant decrease in muscle strength. This kind of patients in the morning if suddenly down to the ground to move the lower limbs, will cause the muscle to produce a transient spasm. 2, there may be excessive fatigue. If the patient did a very strenuous and long-term activity on the first day, it may cause the calf muscles to produce very serious fatigue. This is the time to get off the floor in the morning, a force may appear calf muscle spasm. 3, there may be some peripheral nerve lesions. The more common situation is that when the patient has an attack of severe sciatica, the intense pain will cause the patient to habitually curl up the lower limbs. If the lower extremity is suddenly straightened in the morning, this can cause a pulling stimulus on the sciatic nerve, which can lead to very severe pain. This produces radiating pain in the calf area and leads to calf cramps.