After 5 years, you should be good to do whatever you want. Just work up to your maximum gradually, just as you normally would do.

Jan

I do full situps, started doing them 6 months post op. Crunches have bothered me ever since I had a Tummy tuck a few years ago. Walking can build your core. Just always make sure it is engaged with everything you do. Medicine ball is also good to use.

#1 core builder are planks. Do them in sets of three for as long as you can hold every time.

I have found that the swiss ball ( the huge pilates ball) is a godsend for my tortured abs. I had 5 or 6 hernias (lost count) over 5yrs and gave up on my abs til I got one and used it nightly...no effort, just hanging over it backwards and rolling side to side, back and forth etc, pushing up agaist a sofa or wall and sitting on it...in 2 months I got abs of steel without hurting my abdoment or hernia sites...thrilled!
Sharon

planks and planks with one leg up in the air
and side planks, and side planks with one leg up in the air.
holding each as long as you can. breathing through it all.