I love parkour. Its a great sport. It involves muscle agility and mind. The only bad thing is, it comes at a price. Parkour is a sport which includes jumping over and across things and vaulting. Every once in a while, you mess up. 2 bad for me. I had to learn the hard way. I got injured pretty badly.
Ya, parkour is great, but I'm not sure it can be considered a sport. I've been doing it for a couple of years and most traceurs I meet describe it more as an art form. I'm personally more fond of free-running, because I prefer an atmosphere where a little show-boating is acceptable. I mean, why would you be out there if you weren't trying to have some fun. I've been trying to learn a wall spin, but I'm not having much success.
Some real nasty stuff can happen to you out there in that concrete jungle. Especially clipping your feet during monkey faults and stuff. As long as people don't start trying to roof jump until they're really ready, though, its usually not that bad. Hope the injury wasn't dehibilitating.
Parkour is great, I've been doing it for a while and like it a lot and it also keeps you fit.