Daily Mobility Exercises by Dr. Kelly Starrett Forums General Toes Forward + Knees Out Squatting and Long-term Knee Health Re: Toes Forward + Knees Out Squatting and Long-term Knee Health

#72962

One of the key reasons to squat with your feet turned out no more than 10-12 degrees is the exact reason demonstrates in the video Kaitlin linked. This is to help create torque in the hip by engaging the ER group. THis is the key group in not letting the knee drop into a valgus position. 

Another key reason to squat with the toes relatively straight forward is to use the internal ligaments of the knee to stabilize itself. By this I mean ER of the femur on the planted tibia takes slack out of the ACL and limits the amount of anterior translation the femur can have on the tibia. This basically stops the femur from having excessive sheer force on the meniscus. 
No doubt Rippetoe is a great coach. Just think of it as a difference in philosophy.