What are the best sources of info for overall knee health/rehab. I am getting pain on the outside of my left knee trying to do the third world squat. I don't know if I have tight/loose/weak/overstrong/overstretched thighs/acls/plc/lcls/calves, etc.

But I think something is out of line. I want to read about how to determine proper knee mechanics, how to tell if something is off, and how to fix it. Some exercises that expose whats wrong. What should read up on/look into?

Edit: In case anyone is still reading this and curious, what really fixed it for me was the couch stretch and super couch stretch. I found that I had a lot more flexibility/mobility in my right leg. I think my left quad/hip flexor was just super tight/cramped and there was too much tension when my leg was bent so far. With a lot of couch stretch and lots of time in the third-world squat, my pain went away.

Additionally hip adductor stretches helped a lot as well. I found with my back curved and legs in butterfly stretch, my left knee would hurt. I started sitting up straight and really getting my legs far down in the butterfly stretch. Then when I bent my back again slightly my left knee didn't hurt anymore. I take this as a sign that perhaps my left knee was getting injured slightly when I was doing butt wink/slight lower back bending deep in the third-world squat. Developing the flexibility to avoid this bending/butt wink ensured that my knee stopped getting hit. So I guess it was a lot of things.