When I train my abs (on very rare occasions).. I like to use a stability ball for my sit ups, leg lifts and crunches.
I have found that simple, quality exercises are better than crazy wild ones done in excess. Always use slow, controlled movements.. contract HARD at the top and make sure to breath properly, exhaling all of the air out of your tummy as you squeeze!
(via sweatyfitness)Source: muffintop-less