Stability Ball Plank to Tighten Your Tummy Michelle Douglas Nutrition & Fabulous Body Coach December 11, 2009Here’s another great exercise to help you tone and tighten those tummy muscles! The stability ball plank is a variation of the standard plank. Related posts: 2 Moves to Tighten Your Tummy How to lose tummy fat Here’s a lower body workout to burn fat and tighten that butt!