Abs Sense
For most of us, when it comes to ab workouts logic flies out the window! Some believe that as long as you push the muscles intensely, there's no benefit in doing more sets. Fans of multi-set workouts say muscles need repeated stress to grow!
Many folks trying to build definition for the abs do 5 sets of 10 reps of bench squats.. then turn around and do 5 sets of 100 crunches! This is done under the belief that the abs respond differently to working out than other muscle groups. However, in this case variety is the key to success! Try doing several different exercises, using a variety of equipment, like an exercise ball!
Whether you do one set or a dozen... remember that the abs don't respond differently to exercise than any other muscle group -- and that proper diet is the second part of the puzzle!