My son Will just finished his first season as a high school cross country runner, and he plans to run track this spring. As part of the team's offseason conditioning, the kids do a fair amount of strength and conditioning training.
You wouldn't guess it to look at me now, but when I was in my early teens, I spent a lot of time in the weight room. When I finished growing, I stood — and still stand — at 5 feet, 8 inches. On a good day.
My dad and brother are both a couple of inches taller than I am, and I've always wondered whether weightlifting had something to do with it. So is it safe for my 14-year-old son and his teammates to lift weights? Or does pumping iron at a young age risk stunting their growth?
Dr. Prescott Prescribes
The idea that weight training interferes with growth has a firm hold in the popular psyche. I can't say where this notion began, but it certainly took off in the wake of a study in the 1970s where Japanese researchers discovered that child laborers tended to be abnormally short. The researchers concluded that physical labor, which typically entailed many hours of lifting and moving heavy weights, had interfered with the children's growth.
Today, many parents — and some pediatricians — believe that children and young adolescents should not engage in weight training. The thinking goes that lifting weights can damage the epiphyseal (or so-called growth) plates, which is cartilage located at the end of long bones. Some also believe that weight training in young males is ineffectual due to a lack of testosterone.
In a comprehensive review published a few years ago in the journal Pediatrics, scientists reviewed 60 years of studies of children and weightlifting. That study effectively punctured each of these myths.
The researchers found no evidence that weight training, even in preteens, stunted growth or cause damage to growth plates. It also found that such training in children increased muscular strength in a “linear” fashion similar to adults. Their strength gains, it turns out, were tied much more to how often and strenuously they worked out rather than their ages.
Interestingly, while the children showed strength gains, they did not add muscle mass in the same way that adults — and especially men — did. So perhaps the fact that kids do not get “buff” may contribute to the myth that strength training is ineffectual in the young.
The literature shows that strength training can be an effective way for children to help develop balance and coordination. It can also set them on a lifetime path of staying physically active. And it can begin well before adolescence, between the ages of 7 and 12.
Of course, children should not be dead lifting, doing squats or using heavy weights, and any work with weights should be supervised. But many of the most effective strength exercises — push-ups, crunches, working with a medicine ball — don't require weights at all.
So don't worry about Will doing strength training. And as for your height? Don't blame the dumbbells.
Prescott, a physician and medical researcher, is president of the Oklahoma Medical Research Foundation. Cohen is a marathoner and OMRF's senior vice president and general counsel.