YOU MAY have seen them scaling walls or vaulting over obstacles in Penrith but then again, you may not.

James Wise, 15, and Robbie Mann, 17, prefer to go unnoticed when they train.

``We hardly ever attract a crowd,'' James said. ``And if we do we'd probably move on,'' Robbie said. ``Some people think you're breaking into something or learning how to burgle.''

But an elderly lady in the Blue Mountains was on the money when she commented on the boys' skill and agility.

James and Robbie practise parkour a discipline rather than a sport, as James explains: ``Parkour involves efficient movement from one point to another along a chosen route in an urban or natural environment.''

James, of Kurrajong, and Robbie, of Lawson, have been training every Saturday since October in Penrith at a place they've named The Epic Spot and have broadcast footage of their Penrith sessions to the world on YouTube.

James said one of the reasons for posting an online video was to encourage a few practising people in Sydney to train in Penrith.

``It's still our best spot,'' he said.

The Epic Spot is a wonderland of obstacles. In fact, Robbie pointed to a new one as we were speaking.

James said they kept out of the way of everyone when they trained one of the ethics of parkour is to avoid confrontation and to move on if asked.

James and Robbie met through the Sydney Parkour website and attend classes at the Australian Parkour Association.

Parkour is very physical calluses line their hands but the mental training is equally important.

They must overcome the obstacle in their minds before they move a muscle. Both James and Robbie agreed that many parkour lessons, not just one, were needed before they could venture out on their own.

``It's really easy to injure yourself when you're starting,'' Robbie said.

Strength training is also needed to avoid knee damage.

But more than this, the boys said parkour was a lifestyle. ``It's a choice ... eat healthily, drink healthily,'' James said. Robbie said he hadn't played his video games ``in ages'', James no longer watches television: ``We're doing something positive,'' Robbie said.

Visit the Sydney Parkour website, www.flexibility.com.au/blue/.