Different to some of the famous beliefs, crunches are said to be one of the best methods of toning your abs muscles. Actually, you can perform any kind of crunches as they are stronger and suitable for everyone. Pilates is yet another perfect method of toning and strengthening your abs. You can even perform 12 session challenging exercise which includes rolling up for ten reps for two times in a day. If you perform these ab exercises for a few months then you are sure to tighten your muscles and see a perfect six pack abs.
You can even try a roman chair or a knee-up exercise at the gym. However, if you normally perform side twists, bends and leg-ups they are still not going to work for you even though your abs may appear stronger but it may just not be the same which you would like to have.