Even in today's digitally focused world, kids still love to play outside.

But there comes an age — typically about 10 — when youngsters begin spending more hours playing "Minecraft" than playing outside.

"The younger age-group kids naturally want to be outside and want to play more," said Chelsea Hendrick, a research project manager at Pennington Biomedical Research Center. "The older you get, kids spend more time looking at screens, watching TV and doing indoor activities that take a lot less physical activity."

Researchers at Pennington are searching for ways to increase activity among these adolescents and teens, and to improve their lifelong health.

The Tiger Kids study, begun in January, closely follows the physical activity of 10- to 16-year-olds, tracking participants' movements and asking questions through the week to determine exactly how active they are, while forming a picture of their social and dietary habits. 

"We are really trying to find ways to increase kids’ physical activity and reduce the amount of time they spend sedentary or not moving very much and in general improve their overall health," Hendrick said.

A 2008 study published in the Journal of the American Medical Association found that between the ages of 9 and 15, children's physical activity dropped by one-third. National guidelines recommend an hour of vigorous activity a day for children and teens, but only 40 percent of high school students meet that. 

The problem is that a sedentary lifestyle often leads to unhealthy weight gain, and in Louisiana, 1 in 3 children is overweight or obese, Pennington has found.

That's not typically something they will outgrow. Overweight adolescents have a 70 percent chance of becoming overweight adults, according to the U.S. Department of Health and Human Services. 

Eleven-year-old Laird May was one of the first to join the Tiger Kids study early this year. He is a competitive swimmer and has friends who still enjoy playing outside and riding bicycles around their Denham Springs neighborhood. He's probably more active than many youngsters his age, said his father, Bryan May. 

Yet the youngster is aware of fellow students who don't do much. 

"Some of them kind of like to stay in the house a lot," Laird said. 

When he joined the study, Laird went to the Pennington campus to answer surveys and take medical tests and scans that show such things as body fat and bone density. For one week, he wore an accelerometer and GPS unit around his waist to track where he went during the day — school, a park or the swimming pool — and how fast he moved. This technology helps researchers understand the intensity of a youngster's activity. 

"We can not only tell they took 7,000 steps that day, but that 3,000 of those are at a moderate or vigorous level," Hendrick said.

After school and on the weekend, Laird also answered questions from the research team. Short questions would pop up on a Pennington-issued iPod. They asked who he was hanging out with and how he was feeling. 

These tests and surveys help researchers understand how the kids' lives are structured and how physical activities fit in. What aspects of their lives help them become more active? What prevents activity?

"If they live in a neighborhood full of sidewalks that is walking distance to a park or walking distance to a grocery store, that is going to promote physical activity to that child," Hendrick said. "If they live on a really busy street or live in a neighborhood with a high crime rate, those are things that would negatively influence the amount of physical activity they would get."

The study takes one week, and then two years later, participants return for one more week of testing to determine whether anything changed. About half the spots in the study have been filled, Hendrick said. 

Data from the study will aid design programs to help children and teens keep playing and stay healthy, Hendrick said. 

For Laird's parents, joining the study meant a chance to contribute to science, but it also allowed them to learn more about their son. After monitoring his eating habits, they know he likes a little too much junk food, his dad said. 

"It helped us," May said, "learning that stuff and trying to help him eat better and being more active when he's not swimming or with his friends."

Families who join the Tiger Kids study can earn $100 and learn health information such as blood sugar, cholesterol levels, bone density and body fat percentages. Learn more at pbrc.edu/clinical-trials.

Follow Kyle Peveto on Twitter, @kylepeveto.