I'm doing chris's routine and I don't feel like my abs are really getting worked enough. I'm going to try throwing them in on day 2 for now, and I might do it twice a week later on down the road... I'm just not sure what I should be doing as far as reps/sets go. Does anyone use a swiss ball? And I'd like to use weights as well so I'm not just spinning my wheels doing 50 crunches.