A great interview, and one of the funnest gyms I've ever seen. There's also a whole host of instructional videos at the parkour visions youtube channel.
The explanation of the differences between Parkour and gymnastics was excellent. My favorite quote:
"we take the very basics of human movement – the ability to move on all
fours, the ability to run, the ability to jump, the ability to swing
from our hands and climb – and we apply those to increasingly complex