Box squats work great for me but unless I keep in mind to arch hard and drive my traps into the bar, my chest collapses forward badly. This happens free squatting as well but I get away with it a lot more off the box. Correcting this is helping my equipped squat a lot.
On a side note this is why I love the PL community: those are BIG NAMES giving you the benefit of their experience for free. Priceless. You don't see that in many sports.
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