The age-old question in health and fitness is “how low should I go when I squat?” To answer this question, we must abide by “specificity of training”, which is just a fancy way of saying it depends on what you’re trying to accomplish from utilizing the squat in your training.
The demands of a Crossfit athlete who regularly needs to get into deep squat positions are very different than those of a basketball player. There is no cookie-cutter way and no one-size-fits all approach to squatting. Squatting is not inherently “bad” for your knees, hips, or ankles given that you have the mobility and proper control of the movement. Remember that the movement that is going to hurt you is the movement that your body is not ready for.
To understand knee movement during a squat we can look at the differences between two main types of squats: High-bar placement and Low-bar placement. A high-bar squat is your traditional squat pattern where the torso is upright and the knees travel forward more relative to the feet. This places greater torque demand on the knees and makes it a more quadriceps- dominant movement.
A low-bar squat is more of a hinge pattern and shifts the torque demands to the hips where it targets more of the posterior chain musculature. Depending on the demands of your sport, one of these movement patterns will be a better fit for you. Additionally, if you have knee pain when you squat, these are the factors you would want to take into consideration.