What’s it take to build a pro-level midsection? Cellucor’s Craig Capurso enumerates the 18 most-important rules when it comes to bringing out your abs. Everyone, it seems, has an opinion on the best way to train abs. Whether it’s doing bodyweight ab exercises for higher reps to keep the midsection tight and trim, or weighted moves for lower reps to build up the bricks of the six-pack, the differences are as diverse as the qualifications of the fitness professionals who espouse them.