He couldn't use a trials bike if he wants it to be UCI legal. I don't think UCI says anything about not having a saddle, probably because nobody thought of it.

I was thinking that it would be nearly impossible to do since you have to be standing on the peddles the entire time and really putting a ton of weight on the bars in order to get up a good spin, but with that gear it could work out since he won't have to spin so much. He's clearly a beefy guy, so that's probably good.

Oh. And 50 years old? Jesus.