NEWARK -- Sports4Kids, which operates in about 170 schools in eight cities across the U.S., and which now hopes to expand into Newark and several other urban New Jersey districts, uses recess play to try to improve the way kids interact and learn.

When he first heard about a California-based nonprofit group that tries to improve schools' classroom environment by teaching kids to play recess games, Newark principal James Carlo was a bit reluctant."I don't know why we would need to pay somebody to come and do that," said Carlo, principal of the Newton Street School in the city's Central Ward.

Then a coach from the group Sports4Kids arrived at his school's blacktopped playground, carrying a purple mesh bag full of footballs, basketballs and jump ropes. Instead of recess marked by kids running around and "getting carried away," the students played organized games like "four square" and football, then lined up quietly to come inside, Carlo said.

"He organized games. He taught them playground etiquette," the principal said. "He transformed the atmosphere on the playground in a day."

Recess and kids' play have come under the microscope across the U.S. as schools try to improve academic performance, at the same time experts ranging from the American Academy of Pediatrics to the National Institute for Play say kids need time to play.

"Our intent is to improve the school climate," said Jill Vialet, president and founder of the organization -- she compares it to Teach for America -- that puts coaches into urban schools. They use games to teach conflict resolution, develop leadership, and reduce bullying, teasing and other negative behavior.

The program costs roughly $50,000 per school, Vialet said, of which participating schools pay $23,500. Many of the coaches are from AmeriCorps. The Robert Wood Johnson Foundation recently gave $18.7 million, over the next four years, to help the program expand into 27 cities.

In many urban schools, Vialet said, kids don't know how to play games, leading to "chaotic" recess periods, after which they're unable to settle down in the classroom.

"When I was growing up, there was a lot of opportunity for unsupervised play. I was taught a real culture of play by other kids in the neighborhood," Vialet said. "Now many kids haven't had the opportunity. For lower-income kids, there are concerns about neighborhood safety. For a lot of kids, video games and 'screen time' fill the vacuum."

In some cities, such as Atlanta, Vialet said, kids have also lost recess time because school districts, focused on improving academics, use recess as a chance to grab more instructional time.

By drawing chalk game boards on playground blacktops and teaching kids conflict resolution tools like "rock-paper-scissors," Sports4Kids tries to make recess time count.

The "coach" at each school also creates a peer leadership program, runs an after-school group and organizes some interscholastic sports, Vialet said.

"What we really focus on is the unstructured times of the day," Vialet said. "Our staff creates structured recess, but in doing that they're giving kids the skills and tools they need to take ever greater responsibility for play."

Sports4Kids cites studies and articles showing its benefits. Suspensions dropped in some Baltimore schools, according to Education Week; teamwork and cooperation skills improved at a school in Boston, and transferred to the classroom, according to the Harvard Family Research Project.

At the Robert Wood Johnson Foundation, special advisor on program development Nancy Barrand called Sports4Kids a "very innovative model that provides a lot of benefits to the school."

In demonstrations last month on school playgrounds in Newark, Irvington and Roselle, they also impressed a tough crowd: kids.

"He taught us how to play different games," said Jaylin VanDyke, 11, a 5th grader at Newton Street School.

"It was fun. Fantastic," said fourth-grader Ny-Asia Jones, 10. "We weren't fighting, we were just playing fair."

An 1800s-era building in a gritty part of Newark, most of Newton Street School's students come from families poor enough to qualify for free lunches.

There's a new climbing structure there -- a city synagogue and other volunteers raised funds for it -- but recess often consists of kids running around.

Principal Carlo said he doesn't have the money for Sports4Kids in September but would like to find a grant to fund it in the future. He suggested if kids were taught the games, after a while the program could catch on, on its own.

"Lunch is a difficult time, as structured as we try to make it," Carlo said. "It was nice having someone whose only worry was the playground. It really did make a visible difference."

In Roselle, School Superintendent Elnardo Webster said he was so impressed by Sports4Kids he plans to hire the program for four elementary schools.

He predicts it will allow kids to focus back on school an hour earlier, after recess.

"Our principals are excited," Webster said. "It brings kids back from lunch and recess better ready for instruction. We think it's going to make a big difference."