Well, yes. Crunches will build up the muscle and thus produce more definition, but if there's a layer of fat hiding it, cardio and diet modification are necessary as well. I have very little body fat, so I skip right to the good stuff.See, I don't know if ab crunches can really trim or eliminate the fat (adipose) tissue around one's belly. They're supposed to strengthen the ab muscles; thus people with chronic back pain are often encouraged by physical therapists to do core training and ab-strengthening exercises to support their back muscles. Cardio (brisk walking, jogging) is thought to have more effect on burning fat than ab crunches do.
