I took the advice to keep my shins near-vertical in most of my squatting. I wasn't playing any sports (just powerlifting) and over time I've discovered that I've lost strength in my knees in the knees-over-toes position. This is the position the knees assume when braking a quick run or descending into a powerful jump.
I've started doing higher bar squats which get the knees out a little farther over the toes, as well as some occasional front squats. They've helped, but I've still been feeling very unstable in the knees forward position.
Lately I've adopted daily bodyweight Hindu squats so my knees could get some strength in that position, but recently I discovered that quarter/half Hindu squats are even better. This is the position that PTs have been trendily warning people from getting into. But if you don't use it, you'll lose it. I'm regaining strength in that position and my knees are feeling better.
To see what I mean, stand up straight. Rise up onto the balls of your feet and let your knees bend so that they go way forward of the toes. Keep the torso upright and descend just a few inches so that your torso remains upright and you end up well above a parallel squat.
I'd lost the ability to maintain that position at all. I'm reacquiring it now. I do high rep bodyweight-only sets of Hindu squats to the full and half positions. I will hold both every few reps or so.
It's sad that the trend for the past few years has been to treat knees-forward as unnatural and even dangerous. I trace it to one style of squatting suited to multi-ply geared powerlifting becoming enormously popular. We've been pretending that quads aren't that important for athletic movement and that athletes never have their knees way in front of their toes on the field. But being strong in the knees forward position isn't just the prerogative of athletes; it's a basic trait of healthy knees. Being able to good-morning squat several hundred pounds while being too weak in the knees to squat with knees forward screams of imbalance.
