If Boyle believes the low back is the limiting factor in squats why not do belt squats? What’s he going to do when one of his trainees gets hurts loading a single leg squat with monster weights?
When I first found Boyle I got sucked in to his hype, he sounded like a really experienced guy. It didn’t take too long until I realized he doesn’t constantly change his program because he’s growing, it’s because he has no idea what works so he won’t stand behind or stick with anything.