Back Squat Bar Placement

For the back squat, we need to position the bar in a way that keeps it secure and comfortable while also reinforcing the posture we want.
Squeeze the shoulder blades back together and extend the upper back as you brace your trunk. This will help keep the back more rigid, which also makes maintaining upright posture easier.
The retraction of the shoulder blades will also gather the upper traps to create a muscular area to position the bar—it should never be in contact with the bony points of your spine.
Place the bar in the meat of the upper traps between their tops and the tops of your shoulders.
Use a jerk width or narrower grip. This will help with the scapular retraction and upper back extension.
Keep the elbows down but slightly behind the bar. Moving them too directly under the bar will make it harder to maintain the shoulder blade and upper back position, and lifting them too high will encourage the upper back to round and the trunk to lean forward.
Some lifters find it helpful to grip the bar tightly, but for others it makes maintaining the position harder—do what works best for you. If you grip tightly, make sure it doesn’t cause you to push up on the bar—keep it settled completely on the shoulders.