A child’s legs and body will shake violently a few times at night just after falling asleep may be caused by bedtime excitement, calcium deficiency, nightmares, seizures and other reasons. 1. Bedtime excitement: before going to bed, the spirit has been in a state of excitement and exuberance. When you go to bed, the spirit has not been completely relaxed, and the body and legs will shake violently. 2. Calcium deficiency: Calcium deficiency in children can lead to musculoskeletal contractions and spasms, causing shaking, which is more likely to happen at night when sleeping. 3. Nightmares: If a child’s legs and body shake violently at night just after falling asleep, accompanied by facial expressions of panic and fear, it is usually caused by nightmares. 4. Epilepsy: Abnormal discharges of the brain nerves cause the legs and body to shake. If a child falls asleep at night and his legs and body shake violently, if it occurs frequently, it is recommended to consult a doctor as soon as possible, improve the relevant examination, confirm the cause of the disease and then treatment.