Adolescent Girls, Sports, and Body Mass Index

By Kristi Ayars

I would like to interpret for people some research findings that, if applied, will help girls of middle-school and high-school age prevent obesity. Here is a brief summary: Attention has been drawn to today’s trend toward fatter children in our society. Reports from the 1999 to 2002 National Health and Nutrition Examination Survey showed that 16.5 percent of children ages 6 to 19 were overweight. Furthermore, 31.5 percent of children were at risk for being overweight or obese. In response, another study funded by the federal government picked all types and sizes of schools from urban and rural areas around the nation, with all ethnic groups represented.

Two confidential in-school surveys were given a year apart to more than 90,000 7th- through 12th-graders. A random selection of female subjects yielded data from 1,004 girls. It was found that the girls who reported participating in sports activities five or more times per week had a significantly lower body mass index than the girls who exercised only one or two times a week. [Citation: Mitchell, K., & Pauls, J. (2006). Adolescent Health Study: An Analysis of Female Adolescent Sports-related Activity Patterns on Body Mass Index over Time. Journal of Women’s Health Physical Therapy, 30(2), 5-9.]

Applying this research is easy: Middle school– and high school–age girls need to exercise at least five days a week. The type of exercise is not important; what matters is vigorous participation. If a girl who falls into the overweight or obese category sticks with the five-day-a-week fitness habit, she will find that during the course of a year, her body mass index will decrease.

What is the body mass index? Take a person’s weight and height, subtract frame size and muscle mass, and you get a calculation of about how much fat is being carried per unit of height. The adolescent body is growing rapidly; thus, it is better to keep track of body mass index than it is to merely step on a scale and keep track of weight. You want to be putting on weight in adolescence, but in the form of bone density and muscle mass, not fat. Of course there are other factors that play into people’s being overweight, but getting started with a fitness habit at this crucial age brings other benefits, too. These include thicker bones, stronger and more shapely muscles, improved mood and sense of well-being, and better posture and coordination. And it really boosts a person’s confidence to discover she has the ability to stick with healthy habits for the long term.

The Chico Public Library has pedometers that people can check out. These little gadgets keep track of how many steps a person takes each day. Even just trying to fit in a few hundred more (vigorous) paces during lunch could be the first step toward reducing the risk of obesity and all the difficulties and health problems that come from being overweight. As always, consult a physician before beginning any exercise program. If a person has been medically cleared by a physician but wants more specifics on how to get started, how to prevent injuries, and how to avoid aches and pains, an experienced physical therapist can help.

Kristi Ayars, PT, DPT, Simply Results Physical Therapy in Chico, CA