Children’s leg cramps may be related to calcium deficiency, heavy exercise, cold stimulation and so on. 1. Calcium deficiency: due to the child’s rapid growth and development, the demand for calcium is higher, because calcium plays an important role in the process of muscle contraction, when the concentration of calcium ions is low, it can increase the excitability of the nervous system, so that the muscle spasms, the phenomenon of leg cramps. 2. Exercise: When children exercise vigorously, the muscles are in a state of tension, rapid contraction and relaxation time is too short, resulting in muscle spasms, and the production of a large number of lactic acid, calf cramps, aches and pains and other symptoms. 3. Cold stimulation: cold legs at night when sleeping, swimming in the water temperature is low, the calf muscle by the cold stimulation can appear spasm. There may be other reasons for children’s leg cramps, if the cramps continue to be unrelieved, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.