In the basement of a Lee's Summit, Mo., school, seventh-graders pumped iron, ran on treadmills and took strides on elliptical machines as pop music thumped in the background.

It was no health club. It was gym class.

Bernard Campbell Middle School students tested their upper-body strength by scaling a rock wall instead of a lone rope hanging from the gym ceiling. Rather than competing to tag a person out during dodge ball, students challenged each other to maintain their target heart rate.

It's a new view on physical education - one that is taking hold in schools nationally as childhood obesity threatens to shorten life spans. Instead of focusing on sports and athleticism, physical education teachers want to get all their students moving.

"We've got kids in a health crisis," said Dawn Pond, the lead physical education teacher at Bernard Campbell, who used donated equipment to start the school's fitness center five years ago. "We feel like there has to be a change."

According to data from the Centers for Disease Control and Prevention, 15 percent of children and teens ages 6 to 19 are overweight - triple the proportion that were in 1980.

The changes are ushering out the images of gym class in which dodge ball and other games dominated and marginally athletic students worried about being picked last.

Today, schools across the nation are trying to pique students' interest in lifelong wellness with activities such as kayaking and in-line skating. Some are instituting cholesterol testing. Students are being educated on target heart rates and fat-burning zones.

Leading the way is a nonprofit organization called P.E.4LIFE.

"We want to make P.E. beneficial to all students, not just the athletes," said Brenda VanLengen, vice president of operations for the nonprofit organization.

The 3-year-old organization, which has an office in Kansas City, lobbies in Washington to improve funding for physical education and works with schools to change gym classes. The organization helps gym teachers find ways to incorporate innovative technology and equipment into class.

The effect can be seen in physical education classes around Kansas City, where teachers from 10 districts have attended the organization's institutes.

Walk into a gym class today and you see kids at Bernard Campbell Middle School strapping on heart monitors. Students at Blue Valley West High School are using software that analyzes their fitness test scores and tells them how to improve.

Amy Waters, physical education teacher at Nashua Elementary in the North Kansas City School District, plans to incorporate pedometers the school bought to keep students moving during downtime in PE class.

In the Blue Valley district, students focus on endurance and flexibility as well as cardiovascular and muscular strength. Veteran teacher Terry Flynn welcomes the change.

"P.E. has been stuck in a rut for the last 30 or 40 years," said Flynn, head of the physical education department at Blue Valley West High School.

The change in focus has been brewing since the mid-1990s, said Charlene Burgeson, executive director of the National Association for Sport and Physical Education, a professional organization for physical education teachers. In 1996, a surgeon general's report recommended 30 minutes of moderate exercise five times a week. That, along with the obesity crisis, has led physical education teachers to re-evaluate their curriculum.

"It refocused physical education on something that can be appealing and enjoyable," Burgeson said.

"We know that more activity promotes brain activity, and that translates to higher test scores," said Robert Oliver, physical education teacher at the Shawnee Mission district's Trailridge Middle School.

Justin Mawhirter, a seventh-grader at Bernard Campbell Middle School, relishes the time he spends in gym class. He especially enjoys his visits to the school's fitness center, where he tries to improve his record for crossing the rock wall. He now can conquer it in 28 seconds.

"It's a lot better than before," said Justin, speaking of his earlier gym class experiences. "It's nice to have our own choices and do individual workouts."

The activity in gym class has encouraged him to be more active outside of school, he said.

That's the goal, said Nancy Bailey, the health and physical education resource teacher for the Kansas City School District.

"Right now we have the three N's working against us: Nintendo, Nickelodeon and Netscape," she said. "But if we start using our physical education programs to the capacity they're capable of, we can get a handle on this."