So, we’re left here with two important moment arms to discuss: a) the moment arm between the hips and the bar and b) the moment arm between the knees and the bar.
The primary determinant of the how long these moment arms are is the length of your thigh. The shorter your thighs, the less moment you’ll have to overcome when you squat. This is why guys with longer torsos relative to their legs have reputations as good squatters.