Why would you externally rotate the shoulder to bring the lats in when squatting at 4:10? Did he mean internally rotate (like bending the bar around your neck)?
If you listen, he wants the lats to help with extension but also stiffen the trunk. A cue I've heard is basically like what hes saying: pull the bar down into your upper back (almost like doing the top end of a behind the neck pullup) to really lock in the lats. This really stiffens up your torso, creates proximal stability, and prevents (thoracic/lumbar) forward lean.
@@ChristopherHoleTraining I got to give it to him. Nobody before or since has went to such great lengths to avoid a proper squat. It's rather inspiring.