Some children are very involved in competitive sports, but many other youngsters get no exercise at all. That lack of exercise is tied to an increase in childhood weight problems.

Experts recommend children get at least 60 minutes of moderate to vigorous physical activity on most days to maintain good health and fitness and for healthy weight during growth.

An adolescent athlete can never stretch too much, experts say. Stretching to stay flexible is vital—particularly when a child reaches puberty and goes through a growth spurt.

The American Academy of Pediatrics and the American College of Sports Medicine now say that strength training is fine for kids, as long as they are supervised and don't try to lift too much weight.

Children should avoid specializing in a sport until they reach adolescence, the American Academy of Pediatrics recommends. Reason: for every prodigy who becomes a successful athlete, thousands of youths suffer physically or psychologically from being pushed to compete at a young age.

Most children depend on recreational and school sports for exercise and fun. But too many young athletes suffer needless injuries.

As concern grows over children's harmful weight, physical education gets less and less emphasis in many schools.

Kids need to move to build cognitive and motor skills and to learn that physical activity is fun.

Rising "screen time" can cost kids the exercise they need to keep fit.

Like adults, children should be physically active most, if not all, days of the week.

The sport helps build strength, flexibility, and cardiovascular endurance. Its all-around fitness benefits make it a good springboard to other activities.