I love the ab wheel. It is a functional and more complete movement than many core exercises. Remember to build up to this exercise properly if this is new to you. Here are some of my fave movements with the wheel.
AB WHEEL WORKOUT
Kneeling rollout, arcing to side
Kneeling rollout, alternate arcing to side
Standing drop to knees rollout
Standing rollout into wall, wall acts as safety stop
One knee rollout
Alternating one knee rollout
Kneeling rollout on Bosu® ball
NOTE: Perform 3 rounds consisting of 30 seconds with break between rounds. Vary duration and break time.