Yes I do have Rheumatoid and osteo arthritis, but for the most part it's been in my wrist and elbows. I did go with the spd m424 pedals and that helped a lot over the 520s. I really don't think the 520s have a big enough platform and the 424s do. I'll have to see if medicare will pay for some kind of doctor to get checked out. Maybe my RA doctor could, I'll have to check it out, thanks again guys.