Antonio, a fifth-grader in Oakland, California, started off the new school year by spending more time in the principal's office than in the classroom.

So it was to his surprise that he was asked to be a "junior coach" by the coach of an urban fitness program called Sports4Kids.

There was a hitch; however, Antonio could only keep his position if he improved his behavior both on and off the playground.

A month later, Antonio's teacher reported that he had made "a complete 180 degree turn around" in both attitude and schoolwork. Now Antonio has a reputation of being one of the best junior coaches in his school.

Sports4Kids is a non-profit organization based in San Francisco, California, which gives former "troublemakers" the opportunity to transform themselves into positive role models and leaders.

Jill Vialet founded Sports4Kids in 1996, after a frustrated elementary principal serendipitously asked her if she had any innovative ideas on how to help kids stay out of trouble during recess. At the time, Vialet was the Executive Director of MOCHA (Museum of Children's Art in Oakland) and was successfully connecting artists with elementary school classrooms.

Eleven years later, the program started by Vialet has influenced the lives of more than 52,000 children in many low-income communities, by introducing safe and creative ways to get kids to play and be more physically active.

"The mission of Sports4Kids is to improve the health and well-being of children by increasing opportunities for physical activity and safe, meaningful play," said Vialet.

Beyond San Francisco, the program is now used in 131 low-income public schools in Baltimore, Boston, and Washington D.C., and future plans include expanding it to more cities.

Health counselor Jane Jacobs said that cultivating an environment in which youths can feel safe is key to preventing behavioral issues, depression and anxiety.

"When a child does not feel comfortable or safe in an environment which has been expressly designed for children's play, such as a playground or children's park, it can cause anxiety and increased stress in the child," she said.

Coaching the fifth- and sixth-graders on how to be leaders and role models for their younger peers on and off the playground is what makes the Sports4Kids approach so uniquely effective, said those involved with the program.

"One of the most powerful things we can pass on to the next generation is a sense of their place in the world and specifically, in the communities in which they reside," says Vialet.

The program also discourages participants to shun the violence that sometimes takes place in professional sports.

Sports4Kids relies on three rules to ensure a safe playing environment for all levels and abilities to partake in:

—Respect the Game

— Respect all players, coaches, referees, league officials, fans, and equipment

— Keep a Positive Attitude

And principals and teachers say it's working. According to a 2006 study:

— 94 percent of principals indicated that since having Sports4Kids, students are more physically active.

— 85 percent of principals said the program has cut down on the number of students standing or sitting at the edge of the playground during recess.

— 70 percent of principals reported that over the most recent school year the number of fights happening on the playground was less than the previous year.

— 76 percent of teachers said there is more cooperation between students.

— 64 percent of teachers said that playground conflicts are less likely to continue in the classroom.

— 61 percent of teachers said students are more focused in the classroom.