Okay, there are two things I’m going to tell you first is if you do a search you’ll find the following thread:
The second is that the important part of the thread is:
[quote]Okay you’ll hear people tell you that squatting is bad for the knees and truthfully it can be. That having been said it’s not if done correctly.
If you let your knees come together while squatting this places a great deal of stress on your ACL. Since your ACL is already being stressed by the quadriceps tendon pulling on the tibia let’s not agrivate the situation. However, if you keep your knees apart this is not an issue.
Keep in mind that this is addressing the angle of the femure so knee movement relative to foot position. If you’re standing with your feet close together of course your knees will be close together. The concern is when your knees come together during the movement.
The second concern deals with mechanical impingment. When you squat the axis of rotation is your knee. That is to state that your knee is working as a hinge.
When you squat very deep your calf and hamstring will connect. This connection will change the axis of rotation to the point of contact between the two muscles. This will cause your knee to be pulled “open” like a pair of scissors. (I really wish I could upload a pic into this forum). So long as your deep squat ends prior to this severe impingement you don’t have anything to worry about from the knee standpoint. This is why bouncing out of the bottom is the ultimate evil in a squat. It causes this scissoring motion of the knee and can cause great injury due to the force generated by the bounce motion.
The whole knees behind the toes thing is a common misconception. If you have long femurs then your knees are almost guaranteed to pass in front of your toes if you go past a 90 degree bend. My knees pass my toes well before parallel unless my feet are very widely spaced.
Couldn’t have said it better myself.