Children at the age of 13 are in their adolescent stage of development, growing faster and having more active bone growth, so it is easy to cause calcium deficiency during this period, causing spasms in the muscles of the legs, which can lead to leg cramps. The cramps are especially noticeable at night when sleeping. Therefore, after a 13-year-old child has leg cramps, he or she must pay more attention to keeping warm, and then eat more calcium-rich foods such as shrimp, soy products, dairy products, and lean meat. And you can take calcium tablets and vitamin D orally to promote the absorption of calcium, which is good for growth and development and can also relieve the symptoms of leg cramps.