I'm sure that you are aware, most of your customers must be suffering from back pain. I suffer often, especially when doing anything physical, such as collecting the packages and assembling the machine. I was in severe pain by the end of the assembly but was happy to notice that the pain was reduced after only one day of doing the exercises. I find now (it has been a few days) that most of my pain is coming from muscles that I have not had to work in a long time, such as my wrists, forearms and neck/shoulder area. I think this is all good though. My stamina on the machine has improved from around 3 minutes per session to 8:30 this morning. Once my moving parts get accustomed to the extra work, I am confident that my spine will be much improved and I will be able to get more active in sports again.