Kids are taking in too many calories. The tendency is to put a child on a diet, but that is going to create pound flexing. Parents should focus on weight maintenance and helping the child grow into his weight along with encouraging regular physical activity. Children this age are developing their bone structures. Research shows weightlifting can be counter-productive to bone development by putting kids at risk for growth plate injuries.
Long distance running for young children can cause fractures.
If a fracture goes through a growth plate, even after healing, the plate cannot produce new bone, and a bone-length discrepancy may occur. Which Olympic sports are child-friendly John Czarnecki of the Training Room in Troy rates the various Olympic sports according to whether a prepubescent child can safely participate. Young children involved in any sport require close supervision of an adult and age-appropriate adaptations. For instance, bobsledding with young children should involve slow-moving courses and safety equipment. Young children should focus on skill development, not contact.