Erana said:
OH GOD THEIR KNEES WILL BE SO BAD IN 25 YEARS.
Really, that's exactly what I think in my brain, over and over when I see it.
I can imagine it would feel exhilarating at the time, but with a genetic predisposition to bad knees, I'm not interested in risking it.
I also have to wonder how badly they get scraped up, slamming into brick walls 'n such as they do.
No reason to worry, now. If they did things correctly, they'll be all fine until they're 70.
Speaking as a former Parkour trainee, the amount of damage done to you upon landing is indicated by how much SOUND that springs on impact. No kidding.
Although you can't hear it in the video, if you make no sound upon landing, you've not done any good damage to yourself, but if you stomp... That's a whole other story.
The less sound, the less damage basically. But they could had used a bit more rolls, as they pan out the damage from the velocity in a dramatically decreased manner...
Hope that remedies your worries, though.
OT; Well, I've done many practices, and they were ALL entertaining. When you've got a good group going, you can have fun AND train your body at the same time. Weird, right?