Ab work without strain?

you could try plank holds on your elbows, those are a pretty good workout and shouldn't cause much stress to the back or neck

If you're having neck pain while doing crunches, you're pulling on your neck which is a no-no. Finger tips behind the ears and just touching. Not hanging onto. Look at the ceiling and make your abs do the work.

Belly dancing is excellent for core work too.

Reverse crunches and knee ups........ Do you have a bar you can hang from? Bring both your knees up to your abs. Do lots of them. Do some of them, with a twist, as your knees come up. I have neck problems too. You really still can do any kind of crunches and sit ups, just make sure you are making your abs do the work, dont pull on your neck, only fingertips behind your ears, as someone else here said.

sit ups can wreak havoc on your back but... crunches? They barely register as exercise. How are you doing them?

Just wanted to echo those who mentioned squats and deadlifts, and overhead presses as ab workouts. These massive compound movements have done more to strengthen my core than I thought was possible. Flat-land sit ups are now ridiculously easy and I credit squats for that more than anything.

gmallan I wish I could like your comment! I'm doing Clinical Pilates with my physio and my core is getting so strong! Even my abs are defined. Win win I say. I recommend getting an exercise ball. My favourite core strengthening exercises at the moment are:
Pike Jackknife -Get into the push up position but rest your lower shins on the ball. Use your core muscles to lift your bum as high in the air as possible then back down. Making sure the movements are slow and controlled. LOVE THIS ONE!

Slalem Tucks -Same push up position with you shins on the ball. Slowly alternating bring both your knees to each shoulder, returning to said push up position between reps.

Circus Trick 1 -I guess the physio didn't have another name for it. Do you remember as a kid laying down on your back and bringing your legs over your head lifting your back off the floor? Well one of the tricks is like this. Except, you hold the big exercise ball between your feet whilst doing it. Try to make sure that once you lift the ball off the ground with your feet that your legs remain reasonably straight. Tap the ball behind your head, then tap the floor with bent legs when finishing each rep.

Circus Trick 2 -Lay on your back. Grab the ball with your feet and hold it in the air with straight legs. Slowly rotate the ball with your feet, in a scissor like motion. This is amazing for the core!

Pilates. Make sure you take a class with Pilates because a live instructor can show you modifications for your strength level. If you start out with the modified moves, you will quickly build enough strength to do the more advanced ones.