i think it's fine, i've been doing real situps and i've even used the ab machine at the gym. Now, when i'm not super lazy, i do the insanity cardio abs, and it's not easy on the stomach! i personally think its better to keep the core strong, so you won't have as many problems with muscles.
UC for 8 years, before finally kicking its butt and having a permanent ileostomy April 17 2007!
-I have gone to find myself, if i get back before i return, keep me here-
No matter what kind of day you are having, take five minutes to sing loudly and dance like a fool!