Who can tell me a great move to get a flat stomach when working out? I do a lot of knee raises to my stomach as well as traditional abs crunches on the floor. However, I am looking for more alternatives to keep my stomach tight and fit. I have seen great videos on YouTube but never made the effort to include these exercises in my own routine because they seem to be modify variations of abs workouts I already do. What are some of the beneficial moves you do to keep a fit stomach?