I'm really worried Teddy or Sophie can get it. What does it feel like? I usually check their knees quite often, Teddy is not overweight, well none of them are but he does jump A LOT on and off beds, couches, etc. As soon as he learned how to jump that high he wouldn't stop. I stretch him everyday anad massage him and when i feel their knees it feels like a pop. Is this normal? None of them seem to hurt or anything.. My knees kinda pop, and that's normal...