if you have back problems- consider something i did a long time ago. back was killing me neck wasn't much better. i rigged a chair to tilt several degrees backward. i had to make a lot of changes to permit working this way, but it allowed me to work much more comfortably. this may sound nutty, and might not be for everyone, but it worked for me. i worked this way for 2-3 years, and the pains seemed to go away. i sit normally now.
I must say that I've noticed a huge difference since switching to Airtact. I would always feel a pull of the muscle going through the right hip to the lower back when using the pedal for a long time. However, if I put both feet on a plinth that was level with the pedal and just used my toes and ball of foot on the pedal this helped to aleviate the pain by 90 - 95%. I can honestly say that since using Airtact it has stopped any of the low back/sciatic pain I used to suffer from.
Since using the PalmControl I have had far less problems with my back. It is nice to be able change my position frequently. I generally have my feet in closer to my chair now. I have also seen less neck strain since using a headrest.
Ergonomics is a big thing I emphasize in my classes. I think if you are having backproblems while engraving you are doing something wrong with your body position unrelated to the footpedal. Too many people try to adapt their body to a standard bench that they have , rather than adapting the bench to your individual physique and this can lead to a multiple of problems, some that will not be expereinced until years down the road.
You need to get your body first into a comfortable working position, per any good ergonomics study(either sitting or standing, your choice), then bring in whatever optical aid you are using (nothing, optivisor, microscope, etc) then go the end of your focal distance, and that is where the top of your engraving project,i.e., about an 1/8" above your vise top usually, is where you have , I say HAVE TO HAVE have your vise top. Of course whatever is supporting the vise, will have to be at the bottom of whatever type of vise you are using. Often this is much lower than most people imagine, depending on which vise style you have.
scott is on the money. you must be comfortable. you also must be free of tension or strains of any kind. you have to be loose and relaxed. this kind of work is plenty demanding. you simply don't do well if you're all tensed up. think of a singer or musician who works under tension. you can hear it in the voice or music. the engraver will show this in the work they do. it will show visually. when things get a bit tense, take a break. your muscles and eyes will do better work in the long run.
One thing that I notice with Sam is that he doesn't get up and move around. I suppose he is so absorbed in his work that he doesn't realize hours go by without him getting up and walking around.
I often stress to my patients that are having neck pain or back pain that staying in one position for too long (at a computer for example) can be so detrimental. I think my patients listen better than my husband!
Abigail
Something that I have fund that has helped with my back and right arm, is getting into the hot tub my wife made me buy her when I got my new boat. It sure does make a difference after engraving for a long time.
abigail is right. you, at least i, tend to stay put for long periods. time has a way of just rushing by. but i've luckily learned to relax whilst doing this work. it's not the problem it once was for me. older folks should take a break every now and then to get the blood circulating in their legs. this can cause serious problems for people with poor peripheral circulation, especially those who may be diabetic.