Rashaad Gomez stretches before practising parkour in a park in New York October 7, 2013. Parkour, the free-wheeling outdoor sport of vaulting, bouncing, jumping and flipping through the urban jungle, has inspired a new breed of indoor fitness centers where buildings are boxes, sidewalks are mats and caverns are foam pits. Fitness experts say the soft landings, controlled environment and instruction in these gyms have transformed the risky pastime of urban youth into a fitness option accessible to just about everyone. REUTERS/Carlo Allegri (UNITED STATES - Tags: SOCIETY HEALTH)