The physical therapist showed me how to turn the handle only rotating my lower arm. The Go has to be at the proper level about waist high for me. I keep my upper arm next to my body and it and my shoulder does not move. I guess some muscles move there but none that hurt me later. I don't have to put out extra oomph it is smooth turning now that I learned the proper way for me. I can cut for a couple of hour and have no pain or aches.