I'm an 18 year old female and I gain muscle fairly easily if I try. I am slightly underweight (5'5" and 107 lbs on a small/medium frame) and I recently started doing crunches. My obliques(Is that the right term to describe the sides of your stomach?) have significantly more tone but the middle of my stomach looks larger now. I do have a little bit of extra skin from losing 49 lbs since last year ( it was all antideppressant weight gain) but am I doing crunches wrong and building muscle OUT instead of IN? My muscle tone seems to just be building out and my stomach looks fatter instead of flatter. Sorry if that was confusing http://www.healthboards.com/ubb/smile.gif

Building muscle is exactly that, BUILDING.
If you are not overweight and you're adding muscle to any part of your body that isn't covered in fat you have to expect that part to become bigger because the muscle is getting bigger.

The fact that you are underweight probably accentuates this.
try other weight training exercises as well and bring the rest of your muscle into proportion with your stomach muscles.

Yeah, I should concentrate on other parts of my body, as well as my stomach. Thanks so much http://www.healthboards.com/ubb/smile.gif