Saturday morning I was kneeling on the floor and as I got up, I twisted my knee. It really hurt and I struggled to put any weight on it. I was about to get in the car for an hour and a half journey as a passenger so I did, and by the time we got where we were going it was fine. Sunday morning I was kneeling - it happened again. I sat down for about an hour and once again it was fine. Same again this evening. I'm going to take it to the doctors tomorrow, but I like to be forewarned. Anybody know what I've done?