I agree with Patrice. My mother used to tell me, "If you can't BE tall, STAND tall." I always think of this when my back gets tired. I try to sit tall when I am sewing. My issues are not so much my back as my sciatic nerve in my hip. I have had this problem since my 45 year old son was born and they hit the nerve when giving me an intramuscular shot. I can't sit too long at one time. That is why I move around a lot when sewing, sew, iron, sew.