It's time for parkour.

The typically outdoor, urban practice consists of moving through an environment in the most efficient way possible by running and leaping over such obstacles as railings and steps.

The men and women of parkour, known as traceurs and traceuses, respectively, get together in what is known as a jam and attempt to clear challenges using their bodies.

As with any physical activity, injury is possible, but seeking guidance from those with more experience can help mitigate the risks.

That's where the NY Parkour Academy comes in.

"The risks are real and you can hurt yourself," said Exo Dae, the academy's head instructor. "But if you get around the right people, you most likely won't."

Classes at the NY Parkour Academy, which return this Sunday, cover the basic techniques and movements of parkour. Fair warning: they can be physically exhausting.

"[Students] will get a workout," said Dae. "They should come with an open mind and prepare to have fun and condition. Conditioning is key."

Don't expect to go up against your fellow traceurs or traceuses, either. Parkour, which is also currently featured in the movie "Brick Mansions," is not meant to be a competition. Rather, the training regimen, which utilizes techniques from military obstacle-course training, tests the pracitioner's own ability.

"I define it," said Dae, "as the art of physical conversation with one's environment through movement."

NY Parkour Academy classes are held Sundays from 3-5 p.m. at the East River Park Amphitheater on the East River Promenade, enter at 478 Cherry St; $25, nyparkour.com/academy.