Sometimes I have back weakness. It doesn't hurt, but after a long ride I'll be very stiff. If there is a period of time when I don't ride like winter I'll experience it more extremely. To diminish this condition I try to exercise my lower back. Stretching helps as well.

Another related condition to bicycling fever is low bone density. So occasionally I take a long walk or a short run to give some density to the skeleton. Gotta keep the bones dense!