patricej

i think i'd have to agree with those who "worry" it might not be your safest option.
a power cutter is bound to be heavier than a standard rotary cutter.
your two conditions together increase the chance of accidents with such a device.

here are some things you might be able to do to reduce your discomfort when cutting:
1. check the height of your cutting surface. if it's too low, you can't cut in a comfortable position. your surface should be at at least high enough to reach just below your belly button. i recently indulged myself in a fancy-shmancy ironing center. it's just a small cabinet with leaves on each side that create a long, rectangular surface. the pad comes off, so it doubles as my cutting table.
2. sharpen your blades often and change your blades to new ones more frequently.
3. check out some of the ergonomic cutters now on the market. can you get to a quit show? that would be a good chance to test a variety of cutters without spending money first in search of just the right cutter.

the Simplicity electric strip cutter can do a very nice job cutting long strips, but it does take practice. a lot of practice. (i also found that it's easier to get a clean, straight cut if i starch the heck out of the fabric first.) i use mine to cut binding strips. i always run scraps through mine first each time i use it so i can retrain myself and find "the zone".