Again, I like to focus on endurance when it comes to abs because they’re stabilizers. I wouldn’t really do anything under 20 reps. If you can do a bodyweight move for say 50 reps, then adding some resistance and control to cut that number in half is a smart way to go. But I also don’t consciously think about reps — instead I think about feel. I don’t want to get to that point where my rep speed decreases. At that point, I’m done. I don’t want to break down too much muscle tissue. The speed shouldn’t be hindered over the course of a set. Once that slows down you hit that breakdown point.
