I've been playing for 30+ years. Started with footstools (there was nothing else back then). I've tried the various alternatives and used a large Dynarette for many years. To guarantee the proper height I also took a particular chair with me whenever I played. Now I'm back to using a footstool because the use of the dynarette started causing some numbness. Over the years, I've found that the back problems I had were not caused so much by the footstool as by lack of exercise, flexibility, etc. I've been using the footstool with no problems, but I do exercise regularly to keep myself relatively limber and to have adequate muscle strength.