At 66, my back as occasional flareups from sitting wrong or lifting things wrong; relieving pressure by riding in a somewhat stretched-out position is usually the best thing I can do to ease the discomfort.

To that end, all my bikes have clip-on aero bars that comfortably stretch my back. The pedaling motion seems to work as well as physical therapy would.

It works for me because my discomfort is from simple compression. If you have damaged disks or other structural problems, consult a doctor, of course.