Researchers found that of more than 1,700 teens, those who played on at least two sports teams per year were 73 percent less likely to be overweight or obese than those who did not. Those who walked or biked to school four to five times per week were 67 percent less likely to have weight problems.

The findings, however, can't prove those activities prevented the weight problems, or whether something else could explain the link.

Overall, the connection shouldn't come as a surprise to most people, said Dr. William Stratbucker, a pediatrician at the Helen DeVos Children's Hospital Healthy Weight Center in Grand Rapids, Michigan.

"I think this is info that a lot of consumers will see as common sense. If your child is on sports teams, they're less likely to be obese," said Stratbucker, who was not involved with the new study.

The researchers say, however, past research on different activities, including walking to school, recreational activities and playing sports, have reported conflicting results on whether they actually cut down on obesity.

ALMOST A THIRD OBESE

The researchers surveyed students and parents from New Hampshire and Vermont public schools over seven years - starting about 2002. The surveys were conducted over the telephone and recorded several pieces of information, including what activities the students participated in and the students' height and weight.

The researchers used the information that was recorded once the students entered high school, which gave them information on 1,718 teens.

Overall, 29 percent of the teens were overweight or obese.

The researchers, who published their study in the journal Pediatrics on Monday, then looked at which activities seemed to be linked to the least risk of weight problems.

About three out of four teens played on a sports team, and the researchers found that those who played at least two sports per year were least likely to be obese.

Of the 492 teens that didn't play on a team, about 40 percent were overweight or obese. That's compared to about 22 percent of the 927 that played at least two sports.

Keith Drake, the study's lead author from Dartmouth Medical School's Hood Center for Children and Families in Lebanon, New Hampshire, said that playing multiple team sports may help more than just playing one because those teens probably stay more active throughout the entire year.

"It does give kids a consistent way to participate in moderate to vigorous activity," Drake told Reuters Health.

He added, however, that simply playing one sport is probably good for kids, too.

As for walking or biking to school, Drake and his colleagues found those who commuted more than three days per week were least likely to be obese.

Meanwhile, extracurricular and recreational physical activities didn't seem linked to weight.

NOT ALL SPORTS CREATED EQUAL

The study did have some limitations, including that the information was reported by the students and parents, which could introduce errors.

But overall, Stratbucker told Reuters Health that the study shows that it's important for parents to encourage their kids to remain moderately to vigorously active all year long.

He cautioned, however, that just being in a sport does not mean teens are active.

"If a sport is what they want to do and it's limited in moderate to vigorous activity, they're going to have to find that moderate to vigorous activity somewhere else," he said.

Drake added that it's also important to make those opportunities available to teens.

"I think finding efforts to promote sports participation helps in our obesity prevention efforts. And this study - I think - speaks to paying more attention to that," he said.

SOURCE: bit.ly/L9suBT Pediatrics, online July 16, 2012.

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