A dude in my gym is in a wheelchair with an absolutely shredded upper body. This fucker rolls up to the cable fly contraptions with the pullup bar and literally climbs up hand over hand before busting out 15-20 pullups and then climbing down. I worked in a few times and can't keep up. He can climb up, do 20 pullups and climb down and I still haven't recovered from my 10 pullups and I'm no slouch.