Pop music rolls through Sue Erickson's classroom at Jarrett Middle School as her students hop around a rubber mat like drops of water bouncing across a hot skillet. They have the beat — in their feet and in their chest — and even when they're sweaty and out of breath, it almost never feels like a sixth-grade PE class.

"It's a funny thing," Erickson said. "They don't realize they're exercising. I have to explain that dance is exercising."

But something special is happening here, and in public school classrooms like it statewide. As more PE teachers embrace a philosophy that stresses personal achievement over athletic skills — the new wave in physical education — they are creating healthier children who are more attuned to learning because they exercise more.

At the back of the room on this morning, barefooted and doing his best to keep up with the class, was one of the nation's leading advocates for exercise in the classroom: John Ratey, a psychiatrist at Harvard University who says fitness improves brain power.

In Honolulu to lecture educators about his beliefs, Ratey dropped into Erickson's class. He couldn't resist the rubber mat, called a Geo-Motion Mat.

"It's hard to do the first time," he said, grinning. "I could see the challenge. It certainly got my heart rate up."

Ratey's beliefs about the connection between exercise and learning have become a cornerstone of what some educators refer to as "the new PE."

Schools across the country, including many in Hawai'i, are adopting ways to keep students interested in fitness beyond the classroom. That focus grew from the discovery about five years ago that 20 percent of the nation's 4-year-olds were considered obese, Ratey said.

FOR BODY AND MIND

In response, teachers began using activities — small sided games, circuit training, dance — that involved the entire class 100 percent of the time.

But Ratey takes the benefits of regular exercise a step further than the accepted norm: Not only does exercise create a healthy body, but it also creates better thinkers.

A healthy mind learns more, he said, thanks to a protein produced by physical activity — brain-driven neurotropic factor. It's what Ratey likes to call Miracle-Gro for the brain.

"Exercise gets all our brain cells moving," he said. "This provides the soil for this to occur. People who have high qualities of this stuff learn quicker."

The 61-year-old Ratey has studied the effects of exercise on mental health since the mid-1970s, when U.S. runner and Olympic gold medalist Frank Shorter helped spark a nationwide running boom. Ratey has long viewed exercise as a way to deal with depression, anxiety and attention deficit disorders.

He started researching its connections to learning in 1995 but it was not until about 2004 that he found real proof that exercise boosted learning.

A PE teacher in the Naperville School District in Illinois had sparked a fitness revolution, Ratey said. After the teacher began grading students on effort in events like the mile run rather than skills such as throwing a baseball, they became fitter and smarter, Ratey said. In 1999, Naperville's students scored first in science and sixth in math in the Trends in International Mathematics and Science Study.

'BRAIN BREAKS'

It doesn't take much exercise to keep a child's brain alert, he said. Studies have found that four minute "brain breaks" before each class — jumping jacks, push-ups, knee bends, anything that increases a child's heart rate for a few minutes — can improve learning.

"Exercise is like taking a little bit of Ritalin and a little bit of Prozac," he said. "It makes you focused, less impulsive, less fidgety and more motivated."

Ratey was the keynote speaker last week at a state conference of PE teachers; his presence drew about 500 people, which was several hundred more than anticipated. His core message was to get more children moving.

Dave Randall, the state Department of Education's educational specialist for health and physical education, said a lot of PE teachers in Hawai'i are looking for ways to engage their students. Ratey's research, though, has sparked interest and it fits nicely with programs that stress fitness over skill, he said.

"Our goal was to create lifelong physically fit people," Randall said. "To get the research that backs the academic improvement for the kids who are involved, that's the golden goose for us."

INCREASED INTEREST

By stressing personal improvement, children who are not skilled athletes no longer find themselves marginalized during team sports in PE class or bored waiting in line for their turn, Randall said. Suddenly, their interest level in fitness — and their ability to learn in other classes- soars.

"They are not being compared to each other," he said. "They are being compared to themselves."

Denise Darval-Chang, the Honolulu district resource teacher for health and PE, watched Ratey from across the classroom. A proponent of finding ways to get unathletic children to enjoy sports, Darval-Chang said that exercise can promote personal discovery and boost self-esteem.

In some ways, Ratey's philosophy isn't new, said Darval-Chang, a long-time canoe paddler.

"I think he is just substantiating something that those of us who are movers have known all along," she said. "I think what he has done is the homework and gotten the research."

At Jarrett, a new generation of movers is taking flight and Erickson sees it every day. Her students, many of whom get little exercise outside of PE sessions, have become confident, kinder people, she said.

"You start feeling better and you really don't know why, but you just know you feel better," she said. "Then they hook it to exercise and they get kind of excited about it."

Once her students figure out that exercise is changing them, they can't seem to get enough of it.

"It's huge here, right now," she said. "They learn that it helps them in all parts of their life, not just in PE."