You Don't know squat

The most common mistake that people make when squatting is trying to squat on top of the knees. They fold the upper body over their lower body like an accordion (pictured left). This usually occurs with improper foot and knee placement; squatting with your feet pointed forward at a 12 o'clock angle and the knees not pushed out. This is a huge no-no that results in a shallow depth, knee pain, and eventually surgery. 

The proper technique is to have your feet a shoulder length apart, bare feet planted firmly on the ground at an 11 and 1 o'clock position (pictured left). Initiate the movement with your hips, not your knees. The biggest difference between a correct squat is that you are squatting between the knees instead of on top of them.