I've heard good and bad about crunches for building ab muscles...some say there bad for your back, some say if you do them correctly they're not, etc. Any opinions? I'm laying on my back, hands crossed on my chest, rise slightly(hold position for about 5 seconds, suck in gut), and repeat several times. I'm careful to keep my back "tail" flat on the floor. I'm trying to increase definition in my abdominal muscles....I'm fit (trim, no gut, etc) and just want to increase definition in the abdominal area.
