The stability ball ab rollout is a great exercise if you don't have an ab wheel available. But it's also a good choice if the standard ab rollout is too difficult for you right now.

It's essentially a partial rollout since your body isn't going down as far. You can start with a large ball, move to a smaller one as your core gets stronger, and finally do the ab wheel with the full range of motion.

Related:  Big, Thick, Chunky Ab Training

Related:  Band-Resisted Rollouts for Abs