I didn't know exactly where to post this. Anyway, sometime last year or the year before I don't even remember I was diagnosed with this by my general practioner. I had been complaining of pain in my left knee. It only hurt when I moved it certain positions. Also it hurt really bad when I did squats. I just couldn't do them anymore, it felt like there was no cartilage just bone against bone. Anyone the doc said no impact type exercises, no squats, no running. I could do certain exercises though like leg presses and hack squat machine. The doctor also gave me a hand out that said no sudden changes in exercise. Well I was told I could do non-impact type stuff so I tried one of those eliptical machines in the gym one day. Nope that was a mistake, in pain again!. This was a month after I was diagnosed. Also I waited about 1 month and did squats and was fine. Well, a few weeks ago I decided to try sprints. Well it didn't hurt at first just felt kind of out of place, then it hurt but I kept doing it and eventually the pain disappeard. I stoped for a about 2 weeks recently and tried to go back and do it again last week, nope I couldn't do it pain again!. I've cut fat easily enough without cardio before so I guess I am stuck with just walking!. Anyway these past couple days I haven't even been doing any cardio or walking but it just starting hurting again!. It sucks!. Maybe its just stiff or something?. Most of the time I am not in pain at all though. Anyone elese have this problem?.