Katerina Hauskova of Czech Republic watches a parkour instructor defy gravity at Iron Dragon Crossfit Box. Gao Erqiang / China Daily

Subcultural coolness oozes through the masonry and stone pillars of Iron Dragon Crossfit Box, a cross-fit gym and "big boy's playhouse" in Shanghai that services the city's only Ninja Warrior program.

Recently, there has been talk of setting up a Chinese version of the popular US game show American Ninja Warrior, where contestants race around obstacle courses but forego the black masks, throwing stars and badly dubbed death threats.

"The hope eventually is that we all are able to get the TV show running in China, and also the courses to develop the athletes," said Australian-Chinese Mark Soo, a pit bull of a man from Brisbane, Queensland who runs Iron Dragon and also trains celebrities. Kyle Shapiro's LINK Parkour helps run the Ninja Warrior program.

"The top guys are usually the parkour guys," added the 38-year-old Soo, also the founding father of Eternity Fitness, which does cross-fit boot camps. "They are typically the most versatile and suitable for these kinds of challenges. And it's always evolving."

His 1,200-square-meter gym for the physically gifted is full of supersized graffiti, spray-painted motivational slogans, punch bags, circus rings, ropes and even skateboard ramps.

Its motley crew of "circus silk" trainers, hand balancers, Muay Thai kickboxers and fitness-fanatic regulars look like they are ready to deploy to the battlefield. They sniff at broken ankles and neck braces.

"The principle was to create the ultimate big boy's playhouse, where all your fitness dreams can come true," quipped Soo.

While Pudding, an instructor from Sichuan province, was practicing gravity-defying somersaults off a skateboard ramp one evening, a Swedish man with the face of a young Brad Pitt maintained a one-arm handstand in an adjoining room.

"I'm a full-time stuntman, so I kind of had to broaden my skillset because parkour nowadays is such an important part of it," said Joel Adrian, 25. He came to China to study wushu but now works in movies.

Katerina Hauskova of Czech Republic said parkour is all about freedom of expression.

"We're doing things you're not supposed to. We're crossing borders," said Hauskova. "It's freedom. People say, 'Don't climb that rail. But we say, 'Why not?'"

She studies sport medicine in Shanghai and had just returned to the gym from a six-month sabbatical after tearing her meniscus (knee) while performing a side flip.

"We're kind of weirdos here in Shanghai," she said. "It's not like where I come from, where it's more normal to see people doing parkour."

Adrian said it is slowly gaining traction.

"A couple of years ago, this gym would have gone out of business. The rent is crazy. But now the market is ready for it," he said.

"It's like a reaction against the mushrooming of slick and fancy gyms around the city. It's raw and gritty. You can throw chalk around here and no one cares."

matthewhodges@chinadaily.com.cn