The narrow stance back squat is a rarely used variation that places more emphasis on the quads but also limits depth. It may be done specifically in a lifter’s pulling stance to strengthen the legs for the pull, or can be done periodically with an extremely narrow stance for variety.
 
Place the feet in your pulling stance, or as close to each other as desired. The closer the feet, the more straight-forward they should be directed. The knees should move in line with the feet.
 
Note that a significantly narrow stance will restrict hip mobility, meaning depth will be shallower than your normal squat if maintaining proper back extension as you should.
  Notes
The closer the feet are placed and the more the toes are directed forward, the more the knees should move forward in the squat as well. If being used specifically to strengthen the snatch or clean pull, the feet and knees should be oriented exactly how they are in that lifter’s pull.
 
Purpose
The narrow-stance back squat can be used to strengthen a lifter’s pull from the floor in the snatch and clean, or to emphasize quad strength.
 
Programming
The narrow-stance back squat would most often be used once weekly in addition to normal back squats and front squats. Generally sets of 3-5 reps are most effective at loading appropriate for the goals of that squat session—likely 10-20% lower than what would be used in the lifter’s normal stance.