Nothing hard core (crunches of any sort), but
workouts that engage your core
for balance and stability are okay (yoga, tai chi, Pilates, etc...) and were actually reccomended for me. I didn't do them because I felt like a hippo, and my abdominal wall has since torn from lack of, well...anything. Right above my belly button it's bruised and you can feel an indentation where the sides have separated from each other.