The shaking of the feet when the baby exerts himself may be due to physiological reasons, or it may be caused by epilepsy and so on. 1. physiological reasons: the baby is too small, the development of the nervous system is not perfect, so the cerebral cortex for the foot muscle control ability is relatively weak, the baby is subjected to some stimulation or exertion, it will lead to foot muscle shaking phenomenon, as the baby grows up, it will get better. 2. epilepsy: epilepsy is mainly caused by excessive discharges of neurons in the brain, and when epileptic seizures occur, there will be movement disorders of the baby’s feet shaking. If the symptom of baby’s feet shaking when exertion is not relieved after lifestyle modification, you should consult a doctor in time to clarify the cause of the disease and carry out treatment under the guidance of the doctor.