In a country where more than 10 million children ages 6 to 17 are considered overweight and almost half of these are severely obese, it's more important than ever to educate young people about the importance of physical activity and a healthy lifestyle.

Parents and teachers who think children get enough exercise at school may be surprised to learn that only 44 percent of students in elementary, middle, and high school receive physical education according to a survey conducted by the National Association for Sport and Physical Education (USA Today, March 22, 2000). Parents and teachers can take an active role in their children's or students' health by incorporating physical activity with other home and classroom activities.

Kenneth H. Cooper, M.D., M.P.H., founder of The Cooper Aerobics Center, has been a proponent of improved youth fitness for 20 years. In his book, Fit Kids! The Complete Shape-Up Program from Birth to High School, Dr. Cooper recommends the following for an effective kid fitness program:

Daily 30 to 60 minutes of lifestyle physical activity (active play, indoor/outdoor chores, taking the stairs, bike riding, etc.) Three to four days a week Minimum of 30 minutes of aerobic activity or active sports Three days a week, preferably daily Flexibility exercise Two to three days a week Muscle strength training and calisthenics

A structured exercise session consists of a warm-up, aerobic phase, cool down, and strength training.

Warm-up During the warm-up, children do light activity for two to eight minutes. This makes the muscles more elastic and increases flexibility. Try jumping jacks, fast walking, calisthenics, and simple stretching. Aerobic phase Typically lasts 15 to 40 minutes. Walking fast, running, swimming, cycling, and playing soccer or other sports or activities that have an endurance factor are all good ways to strengthen the heart and reduce children's risk for developing heart disease, the leading cause of death in the United States. Cool down A three to five minute cool-down allows the heart rate to return to normal. Walking slowly and doing flexibility exercises that stretch the calves, thighs, lower back, and upper body are good ways to cool down. Strength training This phase of an exercise session should include exercises to increase the strength and power of the major muscle groups of the body, including muscles in the back, legs, and chest. Children and teens can focus on strength training after a cool down or on alternate days. Pushups, pull-ups, crunches, and lunges are a few examples of strength-development activities.