This is a very tough variation of the traditional rollout that can't be done using an ab wheel.

With only one working arm, your body is forced to resist rotation. It's extremely challenging for the chest, shoulders, and lats.

The length of the barbell makes it difficult to keep the bar rolling straight, so it will also build wrist strength (radial and ulnar deviation).

Related:  Build Your Abs With a Barbell

Related:  The 10-Second Core Killer