Preschoolers may not get enough time to engage in physical activity at childcare centers, according to a new study.

While it's recommended children get 120 minutes of physical activity per day, researchers found kids had an average of 48 minutes per day to engage in physical activity at preschool.

That amount of time is "considerably suboptimal,” lead author Dr. Pooja S. Tandon of Seattle Children’s Research Institute told Reuters Health in a statement.

Tandon and her coauthors observed 98 kids age three to five years in 10 privately funded childcare centers for at least four full days, categorizing their time into naptime, indoor free play, outdoor free play, indoor teacher-led play, outdoor teacher-led play or not a play opportunity.

The kids also wore accelerometers to measure their activity levels throughout the day.

Almost three quarters of total time was sedentary, with 13 percent spent on light activity and 14 percent on moderate to vigorous physical activity. Kids only had opportunity for active play for an average of 48 minutes per day, and did not spend the whole time being active.

Best-practice guidelines suggest preschools should aim for 60 minutes of teacher-led play time and 60 minutes of unstructured activity time, the authors write in the journal Pediatrics.

The study found children tended to be more active outdoors and during free play rather than indoors or during teacher-led play.

“Children need daily opportunities for physical activity not only for optimal weight status but because physical activity promotes numerous aspects of health, development and well-being,” Tandon said.

Preschools may cite weather, limited play space, prioritizing academics, safety and comfort as barriers to more active play time, but these are not insurmountable barriers, she said.

“Every time we look at places or programs where children could be active or we’d expect them to be active, they’re not as active as we hope,” said James F. Sallis of San Diego State University Research Foundation. He is senior author of another study published in the same issue of Pediatrics.

He and his coauthors found that kids and teens who wore accelerometers to dance classes also did not get as much physical activity as one might expect, and tended to be less active than kids spending the same amount of time on sports practice.

“One of the things that might surprise parents about the results of this study is you can’t just assume if you sign your child up for an activity-related program that they’re getting enough activity,” he said.

Based on 264 girls from 66 classes, kids got an average of about 17 minutes of moderate to vigorous physical activity, with only 8 percent of kids and 6 percent of adolescents getting the U.S. Centers for Disease Control and Prevention's recommended 30 minutes of activity per class.

You wouldn’t expect preschool, dance class, sports practice or gym class to consist of constant activity, Sallis told Reuters Health by phone, as some time needs to be spent on skill-based instruction.

But “we in public health who are concerned about an epidemic of inactivity are encouraging all sectors of society to think about how they can help children be more active,” he said. “One of the things we would like to come out of this is dance teachers adopting a goal that kids get a fair amount of activity in their programs, and in youth sports and preschools.”

Parents should ask about the classes they are signing their kids up for, and try to sit in on a class to get an idea of how active the kids are, he said.