I took me two years to do a roll-up after recovering from a serious injury!
I teach the roll down phase first when clients are very weak. The eccentric contraction builds up their strength, lessens frustration, unnecessary gripping and the potential for injury.
I tell them to bear the discomfort (not the same as pain!) in the front of the neck (which improves as they get stronger) but to stop if they feel they need it. I also ask clients to rest if/when they feel the work in the back of the neck, usually a compensatory strategy with muscles not relevant to the action coming in to help very weak anterior neck muscles. I find that these front of throat muscles are really important to provide support for our head (especially those with forward head posture) and my clients have much better health now in that part of their body too because of their Pilates practice.
Here is a link for a beautifully explained anatomical explanation of sit-ups and Ab Curls: http://bit.ly/I1S7nk. This applies to Roll Ups too, except for the difference between legs bent or straightened, putting less stress on hip flexors because of the relationship shifts between points of origins and insertion.
It IS a good core exercise, but I recommend extending actively through the legs and heels as one comes up. I also recommend, as Marie Powers mentioned, to inhale as the arms come up toward the ceiling, and exhale as the arms drop towards the torso. It also helps to press your feet against a wall if you are having trouble coming up. Half roll-ups are the way to go if you find yourself “jerking” to come up all of the way. Scapula must be snug to the back and not lifting toward the ears. Pressing through the crown of the head (with chin tucked a bit) when one comes up, helps to NOT work the neck or shoulders too much. R Laney-Meers, Jackson, MS
As a Stott instructor I agree with Joanne D-C on the options offered. Our neck muscles need to be strengthened; avoiding this and other exercises because it “hurts” the neck is not the answer, practise a little at a time.
I have also found that adding a soft foam head pad under the lumbar spine assists those of us who are very inflexible in that area resulting in a smoother, more controlled roll up with no jerking.
I agree with Joanne and my clients with healthy backs roll up and down. The movement is introduced through baby steps. It’s not what you teach but how you teach it that makes the difference.