Children’s leg pain may be due to strenuous exercise, calcium deficiency, viral colds and other reasons. 1. Strenuous exercise: such as running, climbing, jumping rope and other activities of a large number of sports, will lead to an increase in anaerobic fermentation in the leg muscles, resulting in excessive accumulation of lactic acid in the leg muscles, which leads to the child’s leg muscles appearing symptoms of soreness. 2. Calcium deficiency: usually occurs in children with rapid growth and development. Rapid growth can lead to vitamin D or calcium deficiency in the body. Failure to get enough calcium and vitamin D from food or other sources can lead to muscular aches and pains in the knees or legs. 3. Viral colds: When a viral infection causes a cold, in addition to fever, headache, runny nose and other symptoms, it can also lead to the occurrence of benign myositis, resulting in the child’s leg soreness. When a child’s legs are sore, it is recommended that parents take their children to a professional hospital in a timely manner for X-ray examination, trace element examination, blood routine and other appropriate tests to clarify the cause of the disease, and then take targeted treatment.