I have purchased foam yoga blocks that measure about 9″ x 8″ x 6″ and put them under my elbow when I am doing repetitive sweeps during polishing. Maybe it doesn’t seem like much, but when I’m in the groove, I will sit at my machine for several hours at a time. Have a good adjustable chair so you are at a good level and try not to hunch over while you work. Your back will appreciate it!