I like to rotate the Box Squat in from time to time as a different squatting variation. Besides just being another squatting variation I’ll use it to teach a client how to move their hips down and back in order to involve more of the glutes and hamstrings. I’ll also use it if a client is complaining about knee pain with regular old squatting. The Box Squat keeps the shin in more of a vertical position throughout the movement, thereby placing less strain on the knees.
You can squat to any depth, but if possible in the bottom position the crease at your hip should be at about the same height as your knees. You’re also going to take a slightly wider stance than you would with with an Olympic squat and have the toes pointed out slightly. As you descend, think about forcing your knees out to get more of the glutes involved, sit down and back and then reverse the movement while thinking about pushing your knees out again.