Fitness gadgets come and go. Only a few stand the test of time. Here's one gizmo that does: the ab wheel.
The ab wheel rollout might be the most comprehensive exercise you can do to strengthen your midsection. It challenges every bit of your anterior core musculature, as well as your lower back, lats, and shoulder complex (to keep you from "breaking" into an overly-extended position).
Continuing to build that strength is going to keep your low back healthy. That same strength will help you transfer force from your lower body to your upper body, and vice versa. The stronger your trunk, the more weight it can handle before becoming a weak link in your squat and deadlift.
But what happens after you can hammer 10 or 15 solid reps of traditional rollouts? Well, you can continue to add volume, but eventually you'll see diminishing returns if that's your only form of progression.
Here are five advanced ways to keep moving forward with your rollouts. About 2-4 sets of 5-10 reps will work best. As you get to the top end of that rep range, opt for more challenging version.
Adding a weight vest is one of the simplest ways to increase the difficulty. This is the baseline progression; it can be added to any of the following progressions as necessary.
Just throw on a vest. From your knees, squeeze your glutes and abs. This will pull your ribs down and your pelvis under, making a cylinder between your rib cage and pelvis.
From there, position your weight on your hands and think about reaching over your head without breaking your cylinder position.
Once you get out as far as you can, reverse the motion by pushing your hands down into the floor, as if you were doing a straight arm pulldown. This will keep you from starting the concentric portion of the exercise with a "hips back" action, which takes the tension off. ("Hips back" is an uneducated newbie move, by the way, and you see it all the time in most gyms.) Repeat for 2-4 sets of 5-10.
No vest? No problem. You can increase the amount of your bodyweight you handle by elevating your knees on a box, just like you'd do for push-ups.
More isn't better here, though a 12-18 inch box works best. It gets awkward if you increase much higher than that.
Slowing down the tempo or adding a pause is a surefire way to make your rollout more challenging. Try for 5-10 second eccentrics (negatives) or add in a 5-10 second iso-hold at the end position.
Moving from kneeling rollouts to standing rollouts is a huge jump, but one way to bridge the gap is by using a wall as a built-in end point.
Start a few feet from a wall and perform them the same way you would kneeling, just on your feet. Once you get to the wall, return to the starting position.
Start with 5 reps. Once you can do those perfectly, move back 6-12 inches. Start conservatively and brace hard. When you get to the wall, it's easy to lose tension as you reverse direction.
For a new twist, try doing rollouts with a heavy medicine ball. A slam-style ball works best; it doesn't roll as smoothly, making it more challenging.
Using a hand-over-hand action, walk the medicine ball out as far as you can without overextending at your lower back, then return to the starting position.
You can use a pretty heavy ball on these. Just be prepared for a more intense triceps and shoulder pump than any of the other variations.