They’re not wearing helmets…
Second video: I would like to see that the producers of Jackass get a hold of some of these.
I’ve seen the powerisers before, they have a website but i’m not sure what it is. According to it, however, it’s impossible to stand still on them, you have to stay in constant motion.
I dread to think what that does to your spine.
Although, looking at them, it does seem that the frame absorbs most of the shock.