I'm looking at this article, and it's a very intelligent template (despite the dubious 2xtabata, 2x a week idea) which i'm thinking of trying. But how the hell can you do 5x5 pushup/prone jacknife with an exercise ball? I can't load this exercise, so i'm lost as to why the authors included it. I was thinking of doing a one arm bench/sit up from the bench/crunch on the floor kind of thing. Anyone got any ideas?