Cramps are not necessarily a calcium deficiency, but need to be combined with the actual situation for a comprehensive analysis of the relevant causes. The common reasons are as follows: first, muscle cold, such as swimming, direct contact with cold water in the pool, can cause local cramps in the calf muscles, that is, cramping performance. Prevention method is to enter the pool before the limb muscle warm-up exercises, as well as slow entry into the water so that the body can adapt to the water temperature. Second, excessive fatigue or strenuous exercise, such as long-distance running or sprinting can also occur calf muscle cramps, the cause of muscle overwork and strenuous exercise related. Drastic changes in the potential inside and outside the cell membrane of the muscle occur for a short period of time, which can lead to calf muscle spasms and twitches. In summary, calcium deficiency can lead to cramps, but cramps are not necessarily a calcium deficiency. Patients can go to the hospital to draw blood to check the trace elements, do not over-activity, pay attention to rest, but also can be adjusted by calcium supplementation. Patients need to rest more, do not force exercise, temporarily can not walk too much, to avoid overexertion on the body to form a serious injury.