Infant leg and foot shaking may be caused by physiological factors, calcium deficiency, epilepsy and other factors. 1. Physiological factors: Due to the imperfect development of the cerebral cortex in infants and young children, they are not able to fully control the motor nerves, so the phenomenon of involuntary leg and foot shaking will occur only occasionally. With age, the brain and nervous system development is mature, it will get better on its own, without other abnormal manifestations. 2. Calcium deficiency: infants lack vitamin D, resulting in calcium deficiency, which lowers the blood calcium level in the body, and the symptoms of leg and foot shaking will often occur, accompanied by crying and restless sleep and other abnormal manifestations. 3. Epilepsy: When infants and young children have epileptic seizures, the symptoms of shaking legs and feet will also appear, which may also be accompanied by convulsions, vomiting, and bruising. If an infant’s legs and feet shake and there are other abnormal manifestations, it is recommended to take the child to the doctor for examination and treatment to avoid delaying the condition.