It goes without saying that children who are obese would benefit from aerobic exercise. However, they're likely to find the idea of going for a jog or spending half an hour on a treadmill about as appealing as watching Congress debate the fine points of tax policy on C-SPAN.
Fortunately, there's an alternative form of exercise that plays to the strengths of plus-sized kids: weightlifting.
Before I continue, allow me to recap my recent column detailing why it's not only safe but also beneficial for children as young as 7 to start lifting weights with proper supervision. It doesn't stunt growth. It strengthens bones and connective tissue, which reduces the risk of injury when engaging in other physical activities. And it's far safer than playing contact sports like football or ice hockey.
Unfortunately, the idea of youth strength training is slow to catch on, so the opportunity to use it to combat childhood obesity is often missed.
Unlike aerobic exercise, strength training is inherently appealing because it involves short periods of activity followed by rest periods. It's true that 30 minutes on a treadmill is going to burn more calories than 30 minutes of lifting weights. But most likely an obese kid will hate the former, while he could enjoy — and even excel at — the latter.
"Obese kids aren't going to be very good at aerobic activities," Dr. Teri McCambridge, head of the Council of Sport Medicine and Fitness for the American Academy of Pediatrics, told me. "Forcing them to engage in it is hard on their joints and bad for their self-confidence."
David Stodden, who studies motor behavior in Texas Tech's Department of Health, Exercise and Sport Sciences, agrees. He laid out the potential consequences of pushing aerobic activity on obese children in a 2008 article in Quest, the journal of the National Assn. for Kinesiology and Physical Education in Higher Education. "There is a negative spiral of disengagement in physical activity with low motor competence," he wrote, "leading to increased weight and obesity."
Weight training, on the other hand, often leads to a positive-feedback loop, according to Avery Faigenbaum, a pediatric exercise scientist and professor at the College of New Jersey in Ewing, N.J.
"These kids are really strong," Faigenbaum told me. "The skinny kids are always impressed with how much the overweight kids can lift."
The benefits of this go beyond physical health, he added: "I see these obese kids come into my program, and you can tell they're depressed and have low self-esteem because they always get picked last for teams. But with weightlifting, all of a sudden they get respect and friends and an ego boost because they are good at something that is physical."
Faigenbaum also told me research shows that between 80% and 90% of obese youth stick with resistance training, compared with less than half who opt for aerobic training programs.
For example, researchers at USC's Department of Biokinesiology and Physical Therapy and the Keck School of Medicine and colleagues studied the effectiveness of resistance training for 22 overweight Latino adolescent males and found that all but one of them stuck with the program throughout a 16-week trial — an adherence rate of 95%. During that time, the teens reduced their body fat by almost 7%, increased their insulin sensitivity by 45% and had significant increases in muscle mass and overall body strength, according to a 2006 report in Medicine and Science in Sports and Exercise.
While aerobic activity may burn calories faster than resistance training, I firmly believe that when it comes to a healthy lifestyle, motivation rules all. There is no quick fix to being overweight or obese, and you can't sustain something you hate. For obese kids, lifting weights is an exercise they can excel at and enjoy. Kids don't care about cholesterol; they care about having fun.
And the sky is the limit after that. If weightlifting can build their self-confidence about fitness, obese children are more likely to tackle more challenging endeavors such as aerobic activities and pursuing a more healthful diet.
Faigenbaum has witnessed this phenomenon many times in the weightlifting programs he runs in cooperation with New Jersey school systems. "The most important part is to change their mind about their approach to physical activity," he told me.
Unfortunately, availability of weightlifting programs for children is an issue. Elementary and middle school students typically have little access to weight rooms, and even in high schools, the weightlifting portion of phys-ed class is usually limited.
Clinical childhood obesity programs also are reluctant to focus on heavier weightlifting that allows for muscle and strength development. Dr. Larry Yin, a pediatrician at Children's Hospital Los Angeles, told me his program recommends lots of walking and advises patients on how to incorporate this into everyday life. But when I asked him about weightlifting, he said, "We only recommend it for older kids who are specifically interested in getting stronger." Even then he suggests limiting children to lighter weights and having them do many repetitions, which is essentially an aerobic workout, not a strength-building one.
Yin also conducts motivational interviews and makes dietary recommendations at the family level, and I certainly don't wish to disparage his efforts. Nevertheless, the evidence indicates that the medical community should take a closer look at recommending weightlifting that gradually increases in intensity for obese children as a sport of choice to both improve health and their attitudes toward exercise.
Perhaps weightlifting should be what the doctor orders for obese children.
Fell is a certified strength and conditioning specialist in Calgary, Canada.