I find that I have more problems with my back when I sit and sew as opposed to using the sewing machine on my quilt frame while standing. Following the advice of a fellow quilter, I put my sewing machine on my breakfast bar and completed a small sewing project while standing up. I was concerned about the ease of using the foot pedal, but it was no problem.
One drawback about using my breakfast bar is that it takes away from my pressing and cutting surface.
However, sewing while standing is definitely do-able.
The jury is still out whether or not sewing while standing will become my preferred method.