No kidding? Active kids don't get fat?

Anyway, here it is:

The study is titled "Weekend Schoolyard Accessibility, Physical Activity, and Obesity: The Trial of Activity in Adolescent Girls (TAAG) Study." The full version is currently available online at the Science Direct Web site, under the Articles in Press section.

The study says school playgrounds can help fight against childhood obesity but many are locked and inaccessible to children on weekends – especially in poor and minority neighborhoods.

"Girls who lived near locked schools tended to be heavier, and neighborhoods with locked schools were disproportionately poor and had larger minority populations," said Molly M. Scott, lead author of the study and research analyst with RAND.

The RAND Health study didn't find a relationship between school accessibility and increased weekend physical activity rates but they still associated the number of locked schools with higher body mass index* for the girls.

That doesn't seem to make a lot of sense to me. If unlocked schools don't mean more physical activity, how will that help lose weight?

The study found differences in BMI and physical activity by the girls' race and socio-economic status, consistent with the findings of previous studies. Hispanic and African-American girls had 7.2 percent and 7.8 percent higher BMIs respectively than whites, and non-white girls recorded less physical activity than their white counterparts.

"Studies consistently find that people of different races have different BMIs, but the policy implications of that are often unclear," Scott said. "This study identifies locked schools as great points of policy intervention where gains in the fight against obesity could potentially be made."

Since the students in the study are not old enough to drive, researchers measured the girls' physical activity with accelerometers and looked at locations within a half-mile of the their homes -- a distance they might be expected to walk or ride their bikes. Researchers also examined data on the girls' weekend activity levels.

75% of the schools in the study were public schools, and playground and athletic facilities there were locked about as frequently as private schools. Public schools had the highest average number of active amenities and a significantly higher proportion of baseball fields, paved playing surfaces, basketball and handball courts and high-level gymnastics equipment.

More research is needed, Scott said, noting that the study did not measure whether the girls in the study actually used the school facilities for exercise. The fact that girls with higher BMIs tended to live in areas with locked schools also could signal that the girls live in a more stressful, high-crime area or a neighborhood with less access to stores that sell healthy food.


*Body mass index, or BMI, is a mathematical formula representing weight relative to height that can be used to determine whether a person is overweight or underweight.