Wow!
I conceptualise that as needing the same skills as gymnastics. It's not just about strength, is it, it's about things like an ability to rotate etc.
I used to coach aikido and the pinnacle of my achievement was being able to demonstrate a forward breakfall (i.e. a flying diagonal roll) on a hard surface, e.g. tarmac. That took quite a bit of skill for the likes of me, and would be absolute basic beginner for a gymnast, or, by the looks of it, wheelchair motocross, so it makes me really, really appreciate the skill involved in people who can do rather more impressive flips in the air and also appreciate the skill involved in a lot of other moves they do involving speed and turning.
Thanks for the link.