At 8:30 PM on a recent Friday night, in spite of the windiest, most bitter weather the city has seen this season, the basement gym of the Complexe sportif Claude-Robillard was filled with fifty teenage boys jumping off mats, doing backflips off balance beams and crawling around on the ground. They're not gymnasts-they're "traceurs;" people who use the cityscape in the summer in the same way these boys use the gym in the winter. It's somewhere between sport, dance, philosophy and showing off. It's called parkour.

"Parkour is gymnastics without technique," says Eric Corbeil, who at thirty-four is probably the oldest person at the practice. He's not a traceur, but was drafted by the gym's owner because of his twenty-two-year gymnastics background. He helps participants bulk up on that technique they're missing. "You could break your neck or your back if you fall the wrong way, so we show them how to fall and roll on their shoulder."

I spoke to one seventeen-year-old who was introduced by friends to the art of using the city as a gym. He cracked a goofy grin when I asked him what his parents thought of him doing this: "They just tell me to be safe, not to kill myself," he said before bounding off in that awkward, teenage way to bounce off a few more walls.

Parkour, also called "free running," is an improvisational way of moving around buildings, sidewalks, railings, stairs or any other urban structures. Participants use no more equipment than the average jogger, and the way they use the urban landscape is something like skateboarding without the skateboard. Traceurs are a property owner's worst nightmare as they will scale walls, leap over deep gaps and bounce off of handrails. At the same time, they are an architect's dream as they create new ways to interact with space.

Jonathan Rooney organizes the practices and is the founder of the website PK514.com. It takes a certain type of person to excel at the sport, since it requires nearly equal parts stamina, ego and creativity. "I've been doing parkour all my life but I didn't really know that's what it was," he says over the phone. "[It's] freedom. It's exactly what I want to do. I have a little monkey inside of me and I need to release it."

It takes an amazing amount of physical strength and energy to practice parkour, hence the large number of would-be traceurs building up their stamina in a basement gymnasium on a Friday night. While it may seem from an outsider's perspective to be a free-for-all, there are specific moves to get from place to place. In one exercise, groups of five students practice moving quickly across the floor like spiders; in another they take a running leap at a five-foot stack of foam blocks, catapult themselves over it, and land with a roll. There are many wipeouts.

Urban maneuvering is also an exercise in problem-solving. In parkour, a city's landscape is transformed into an obstacle course it was never built to be, and traceurs must figure out how to fluidly get from point A to point B without killing themselves or otherwise getting into trouble. Corbeil says he heard about a kid in Toronto who got stuck scaling a wall-the fire department was called, and the boy was fined several hundred dollars.

"That's when the danger starts, when you push your limits," said Rooney. "For example, if it's a jump, you always calculate the distance. [You say,] 'That's twelve feet, and in the gym I can do fifteen feet, so I can do it.' But what if there's weird little gravel? You take it into account. Or sometimes it's a mental block-you just look back and say, 'Why can't I jump? What's scaring me?'"

Sébastien Foucan is one of the founders of the worldwide parkour movement. He talks about the philosophical aspect of going where everyone has gone before, in a way no one has thought of before. "Life is made of obstacles and challenges-to overcome them is to progress," his website says, "[It's about] being fluid like water ... In practice, focus your attention on yourself more than on the outside world."

Interestingly enough, parkour is already on its way to being commoditized. A decent pair of sneakers is all the equipment one really needs to get started and Nike was quick to pick up on this for their "Angry Chicken" spot for Presto Sneakers. In the ad, a man-in this case, Foucan-is running away from a chicken and eventually evades it by turning himself into a horizontal plank and walking up walls. The spot (by the advertising firm Traktor) has won multiple awards, including gold at Cannes in 2003. You can also buy parkour clothing at Foucan's website, and I've seen PK514 clothing on people about town.

While parkour is still on the fringes, there are already variations within the community itself. Some see it as a simple, non-flashy exercise in fluidity. Some, primarily in England, are turning up the sparkle, adding flourishes to their already-tricky tricks and appropriating the term "free running." (Depending on who you speak to, the term refers to both "classic" and "fancy" parkour styles.)

While the practice has been profiled in several big-name magazines, parkour hasn't yet hit the mainstream, probably due to the intense physical strength and risk-taking it involves. It requires the type of person who is strong enough, brazen enough and skilled enough to hurl themselves at and around concrete structures like a ball in a squash court. Just as skateboarding and snowboarding had their detractors when they first came into the spotlight, the people who practice parkour have a resilient spirit. And if the numbers at Rooney's practices are any indication, watch out-in ten or twenty years, this could be the next Olympic sport.

Melissa Wheeler is getting to know Montreal's culture creators. Her column appears every two weeks. Read more columns by Melissa Wheeler.