Take the “work” out of “workout” for your teen

By age 15, fewer than a third of kids take part in moderate-to-vigorous physical activity on a daily basis. Rima Himelstein, M.D. talks about the importance of exercise and the role of strength training in a fitness program.

by Rima Himelstein, M.D.

Published Apr. 11, 2013, 5:50 a.m. ET

Say the word "exercise" to teens, and they are as likely to look for an escape route as if you asked them to do the dishes. They'll probably say they're "too tired," not realizing that a burst of physical activity will give them a burst of energy. In fact, most nine-year-olds are completely unaware that they are engaging in vigorous activities for about three hours a day— they call it "play." But by the time they're 15, fewer than a third of kids take part in moderate-to-vigorous physical activity (MVPA) on a daily basis.

Why sweat it? For children and teens, as well as adults, MVPA can improve bone health, improve cardio-respiratory and muscular fitness, and decrease body fat levels. For the mind, exercise increases the body's own endorphins (those "feel-good" hormones) and can relieve depression.

How much is enough? School-aged children need at least 60 minutes a day of MVPA that is developmentally appropriate and enjoyable. That's right: exercise can and should be fun, as part of play, games and sports, for example: hiking, skateboarding, brisk walking, jumping rope, running, dancing, and team sports such as soccer, basketball and hockey.

Strength training is a component of a well-rounded fitness program. Strength training and bone-strengthening exercises should be included for 20 to 30 minutes three times a week. Sit-ups, rope climbing, weight lifting, and resistance bands are examples of strength training; jump-roping, running, and skipping strengthen the bones.

Is strength training safe for the growing teen? Some people think that strength training will stunt growth, or that it is only for athletes who compete. In fact, well-designed and supervised youth strength-training programs that follow recommended guidelines and safety precautions are accepted as safe and effective by the American Academy of Pediatrics and other medical societies—and they are recommended for all school-age children. And in just 8 to 12 weeks, a well-designed strength-training program can lead to improved strength and other benefits.

What is a good age to start strength training? There is no minimum age requirement for strength training, but a child should have the maturity to accept and follow directions (usually around 7 or 8). Each youth should have a program tailored to his or her needs.

Here are the basic steps of a strength training program:

Warm-up for 5 to 10 minutes: stretching, aerobic exercise, and repetitions of light resistance increase body temperature and blood flow to muscles.
Learn the exercise with no weight: no-load repetitions are used to develop balance, control, and proper technique.
Pick the right weight: it should feel a little heavier than the teen is accustomed to lifting.
Do a set: at the end of 10 repetitions, it should feel "too hard" to do it again at first. Teens are encouraged to do one to two sets of 8 to 15 repetitions. If the teen can't complete at least 10 repetitions per set with a given weight, then the weight is too heavy. If he or she can do 3 sets of 20 repetitions, then the weight is too light.
Take a break: 1 to 3 minutes of rest between sets is generally enough.
Target the major muscle groups: exercises should include all major muscle groups (chest, shoulders, back, abdomen, arms, legs, balancing exercises across joints and upper and lower body).
Work the core: exercises that strengthen the abdomen and lower back should be included in every strength training program.
Mix it up: use more than one form of resistance, such as body weight, resistance bands, free weights, or medicine balls.
Cool down: repeat the warm-up exercises and stretches for 5 to 10 minutes to maintain blood flow to muscles during recovery.
Take a bigger break: rest muscle groups at least a day between strength-training sessions.

Will strength training help my teen in his or her sport? The best way to increase strength and motor performance in a sport is through resistance training exercises that closely simulate the actions of the specific sport, duplicating sport-specific joint velocities and angular movements.

Strength training is not for everyone. Check with your teen's doctor before starting a strength training program. The AAP suggests that certain youth like those with heart conditions (such as cardiomyopathy) or pulmonary hypertension should avoid strength training exercises.

Safety first and foremost. Responsible coaching and supervision are key to preventing injuries related to strength training in youth. The focus should be on proper technique and not on the heaviest weights. The goal should be strengthening muscles, not making them bigger. Normal muscle soreness needs to be distinguished from pain. Remember the saying "no pain…no gain?" It's wrong! If there's pain, then stop that exercise.

My advice: join your teen with their MVPA and strength training – have fun and stay healthy together. That's a win-win!