Will David Belle fit into this...has he done irreversible damage?
(No sarcasm at all) I just wonder.
I think that's already been answered in the thread, but his dad was a fitness fanatic and he did all sorts of conditioning as he grew up. In any case, I believe David's one of the biggest advocates of slow progression.
But he wasn't an adrenaline junkie like the kids who say they're doing parkour and then drop off a 15 foot building to impress their friends even though they landed badly and did a crappy roll.
But just to show that nobody's perfect, I heard that the Yamakasi had a lot of overuse injuries from the way they trained, though.
+1 to that

Seeing as David belle was the founder of parkour, and that he did years of conditioning, he probably knows what not to do

. Sure, he may be doing 15 foot drops, but he's been training for 20 odd years now, and I doubt he does them every day either.
For the people who think jumping off of 15 feet walls is cool, you are impressing the wrong people. Who do you want to impress? Random people on the street, or people you can train with?