http://AskTheTrainer.com Personal Trainer Michael Behnken, MS, NASM-CPT-PES, CSCS Sit ups and especially twisting sit ups are a great exercise for you. Unlike the crunch, sit ups are a functional exercise. Isolation exercises such as crunches, biceps curls, and leg extensions are not functional exercises. This is not to say you should abandon these exercises, but in order to have a complete exercise and achieve optimal results your program you must include functional exercises. Sit Ups are not really a forgotten abdominal exercise. The problem with situps is if you perform them improperly, you will overuse your hip flexors which could lead to posture problems which will increase the risk of injury. http://AskTheTrainer.com/posture-problems.html