For a truly great set of abs that is not only firm, but functional and strong, you have to work the entire core. The core is made up of multiple muscles, not just your abdominals. This includes your lower back, oblique's,and deeper muscles like the transverse that help cinch your waist. As strong core supports your entire body, prevents lower back pain, and helps you performance other exercises correctly. One of the best ways to train your core is through balance movements.
Using a core balance disc during any exercise is a great way to challenge your muscles in far greater ways than you can through standard exercises like crunches or planks. If you are not quite sure how to use a balance disc, here are five great exercises to get you started. Be sure to keep you core tight throughout the exercise (think of pulling your belly button toward your spine), which will help you maintain balance and support your lower back
Kneel on balance disc with upper body straight (forming a 90 degree angle at the knees), toes lightly touching the floor.