Originally Posted by Arturo Garcia
Adam: you listed Weighed pull-ups as your #4. I have done some weighed chin-ups and pull-ups and personally I don't feel they use the abs MUCH more than regular unweighed chins or pulls.
Interesting you say that; there's an article here that did an informal study that demonstrated that the bodyweight chinup had more activation of the major ab muscles than any other exercise.
(sorta wfs if you're ok with giant bodybuilders)