i get acute tendonitis in my right knee if and only if i descend (walking or running) an incline of more than about 8-10 percent for more than about 150 yds. it happens every time those conditions are met. so i don't do it very often. if have to i'll even descend backwards to avoid the pain. fortunately, i've never, ever, had a problem while riding my bike, which i do a lot.

i'm pretty sure i know when and how i got it (1982, descending too fast down a mountainside into Gardner Mt carrying a heavy backpack, after several days of overextending my physical limitations with said pack ) and i think it could probably be fixed with a little arthroscopic surgery, but i have no plans to do so.

good luck with the doctor.