Running is what triggered it originally years ago. Ligament and cartilage problems I think it was. Could barely walk on it for 2 or 3 months after. I have to be very selective about the sport I do now. I helped a friend move house a few weeks ago and somehow that has messed it up again. But now I know what it is so I know when to stop and deal it it better. I miss being young!

My knee which feels like it exploded says otherwise.