The rider is called a "Monkey" in sidehack racing. I think it's because they have the grip of a monkey to swing back and forth the way they do. Have a bunch of pics of Sidehacks from the Superbike Internationals way back when, at Laguna Seca. Got to meet Gary Nixon (personal hero), Yvon Duhamel and a few others and signed my Bell driver cap in the pits.

What got me was the Monkey bumping along on the burms...with his bum. Definitely went through a set of leathers/race. Balzy Bike racing at its craziest...except for ice racing and the chariot racers!

Thanks for that Jon...brought back some fun memories.