Chad Zwadlo and Mitch Andrejka take turns leaping and flipping across benches, steps and tiers of concrete outside of Orchestra Hall's Peavey Plaza.

Cops on the downtown Minneapolis beat often want to know what they're doing.

"Parkour," they say, explaining that it's a way of moving from one point to the other as efficiently as possible and how parkour and its more acrobatic cousin, free running, have turned into a YouTube-inspired phenomenon.

That's usually enough to satisfy the cops. But the full meaning of parkour, its advocates say, is as much a philosophy as a sport.

"If you go to a playground and watch the kids on it, you won't usually see them walking up the stairs, sitting down and going down the slide to the bottom," said Andrejka, 23, a recent college graduate who teaches parkour and free running at Gleason's Gymnastic School in the Twin Cities. "You'll see them climbing up the side, going halfway down the slide and jumping off the rest of the way. As they grow up, society tells them not to do that, to walk on the sidewalk, go around that wall."

Parkour, he says, is breaking free of those mental barriers and moving "as we are meant to."

The movement is gaining legs, so to speak, thanks to parkour scenes in popular movies such as the opening chase in "Casino Royale," the 2006 James Bond film starring Daniel Craig. The first show of "The Office" in 2009 opened with the main characters doing a bumbling attempt at it, while shouting "Parkour!"

A free-running class at Gleason's is growing in popularity with tween and teen boys, even surprising owner Larry Gleason.

"I didn't know what parkour or free running was," he said. "But I liked the idea because it reminds me of what I used to do when I was a kid. We used to jump off the cliffs by the Mississippi and run and flip over stuff ... and the gym seems like a great place to train people for it. I didn't expect it to become as popular as it has: We've got about 40 to 50 students, and it's a demographic that gymnastic schools usually don't attract."

The interest in parkour, which has origins in France, is growing worldwide, according to Mark Toorock, founder of the website American Parkour, which attracts 90,000 unique visitors a month.

"It's just going out and playing. It strips away all the advertising, all the flashing lights and sounds and noises and artificial colors, flavors, smells and feelings and brings us back to something real and fun and intrinsic in human beings," said Toorock.

He credits Zwadlo, 27, of Eagan, for influencing the Twin Cities parkour scene. According to parkourmeetup.com, the area has upwards of 500 members; between 25 and 30 show up to train, generally at Peavey Plaza. And Zwadlo is one of a very few who make a living from the sport.

"That's what I do 40 hours a week," he says, although that includes coaching a boys' gymnastics team. "I'm pretty much living the dream right now. If I'm working I'm in the gym teaching it, otherwise I'm out here doing it."

Sheila Mulrooney Eldred is a Twin Cities freelance writer.