One-thousand, two one-thousand ... for a second Mike Simmonds is airborne. He leaps across two boulders that are impossibly far apart and in that moment he finds what he calls "exquisite peace".

Simmonds, 21, is a parkour athlete. The sport evolved from French military training and its name comes from the French word parcour (the path).

The basic idea is to get from one point to another, moving your body as efficiently as possible to go around, over, under or through whatever obstacles may be in the way.

It looks like urban acrobatics, part b-boy dance, part gymnastics, but mostly it just looks cool.

So cool that Simmonds and his friend from school days Bjorn de Klerk got hooked about four years ago, when they were both teenagers. "We were pretty naughty at school and sometimes we'd jump over walls and stuff. Then we learnt about parkour groups and that it was actually a sport," says Simmonds.

Today, he and De Klerk are instructors with Concrete Foundation which operates in Joburg North. It's one of a number of parkour training academies in Gauteng.

It's this incarnation of parkour that signals a new wave for the sport, a shift from the mid-'90s fringe sub-culture into the mainstream. Now parkour training classes are available to those who don't necessarily have the muscle-bound physique of Taylor Lautner in the 2015 parkour-inspired film Tracers, even to those who can't remember when last they touched their toes.

The movie title was derived from the French slang traceur, which is what parkour athletes call themselves.

"Parkour is for everyone, because movement is for everyone," says De Klerk. Yes, he's buffed and ripped but De Klerk says he's never been a gym freak - his toned and strong body (and calloused hands) are thanks to parkour, also thanks to a healthy diet and lifestyle, he insists.

When he turns 21 this month, De Klerk jokes, he'll be making a toast with water. The no-booze sacrifice is worth it because the philosophy behind parkour is his life now. The mental muscle bit complements the endorphin rush from the sheer physicality of the sport.

He makes his point with some show and tell. He rushes towards a brick wall, bouncing off it with a backflip to land comfortably on his feet. He shows off the "corkscrew", propelling himself into the air, twisting his body before returning to terra firma with the control and fluidity of a world-class gymnast.

De Klerk also tells of working with an 11-year-old with cerebral palsy. When she arrived for her first lessons she dragged her left foot when she walked. Months later, they got her running. "It's all about using the body's natural movement," he says.

He adds: "You become the master of yourself, your own body. Knowing your limitations and your strengths is a massive confidence booster. Parkour teaches you that there are obstacles in life but you can overcome them."

Parkour could have gone underground and become about anti-social vandals and thugs being a nuisance in the city, we didn't want that

Concrete Foundation includes parkour classes for pensioners and school children. For De Klerk, his parkour training has exposed him to opportunities working as a stuntman and body double for Hollywood A-listers.

Angelique Reichel is one of a small group of women shaking up the boys-only identity of parkour in South Africa. Reichel's caution is that parkour isn't just the cool moves and YouTube video-worthy stuff. As she talks, she squats low and shuffle-jumps to one side - this is how you could get under a table, she says.

"About two years ago I was on holiday and was standing between two rocks. I was too scared to jump between them even though I would have done it easily as a child. That's when I knew I had a fear of moving and I knew I had to break that thinking," the 25-year-old says.

Concrete Foundation founder Dyllon Davidson acknowledges that commercialising parkour may have bruised its street cred. But he says the real damage has come from traceur wannabes watching a few YouTube videos then thinking they can leap off buildings or run through traffic jams tumbling off car bonnets.

Davidson says: "You must start from the beginning, working with every person's personal progression before getting to advanced moves. It's also about developing your mind and yourself holistically, this is where parkour training comes in."

For Paul Gray, chairman of Parkour South Africa, a community of traceurs established nine years ago, the mainstreaming of the sport is a good thing.

As he and a crew gather for a jam session (as traceurs call meet-ups) in Newtown, jumping on and off walls, bollards and stair rails on a Sunday morning, he says traceurs have a code of discipline and camaraderie.

"Parkour could have gone underground and become about anti-social vandals and thugs being a nuisance in the city, we didn't want that.

"The philosophy of parkour is 'be strong to be useful', it's not about one-upmanship ... You push yourself and the space you're in to the limit, you unlearn saying 'I can't' and take responsibility for yourself, for the spaces where you practise and for others in that space," says Gray.

Gray's words contain a residue of the military origins of parkour: fraternity, accountability and a take-no-prisoners mentality. At the same time parkour is ditching its elitist and exclusionary image.

There's an absence of hierarchy and an embrace of the freedom of movement, however and wherever it takes you. Its strong core means that whatever swirls at the edges is just movement, not what sways you.