In the weightlifting world, athletes will back squat with the bar sitting “high” on the back. In the powerlifting world, athletes will roll the bar down to a “low” position on the back.
The difference in the lifts are found in the musculature. The high-bar squat is going to use the anterior muscles to move the bar (hips, quads, and abs). The low-bar squat is going to use the posterior muscles to move the bar (hamstrings, quads, and low-back).
Now, this isn’t to say that you don’t use the posterior muscles in the high-bar and anterior muscles in the low-bar… you definitely use all of these muscles when squatting in general. But mechanically, your body is going to favor the front or back muscles more depending on the angles at the hip and knee.
As an example, here’s a beautiful picture I drew below:
On the left, you can see that the hip angle is smaller than the picture on the right . Where there is more flexion at the hip, less flexion is required at the knee (the opposite is also true). So the low-bar squat on the left requires less flexion in the knee than does the high-bar squat on the right.
As a result, the low-bar squat is easier on the knees where the high-bar squat is easier on the back and hips.
But assuming you don’t have pain, which one should you choose?
I answer that question today in this video below: