It is probably no surprise to anyone that I think we can learn from how children build strength and then apply what they do to our own training. Children seem to know how to build amazing strength on their own simply by learning how to move and exploring their surroundings.
No one teaches a child how to crawl. They learn how to do it through the spirit of exploration. No one teaches a child how to walk - sure they encourage the child to walk, but a child just figures it out through determination and adventure. The same is true for squatting. No adult needs to teach a child how to squat, though every adult could probably learn how to squat from watching a child.
You may be thinking, "but these are just movements, this is not strength training." It absolutely is strength training though. A child builds a tremendous foundation of strength while they are growing and developing. They even engage in real strength training once they establish a foundation for strength. Have you ever seen a child try to pick up a heavy ball? They test their strength and build new strength by attempting to lift things up off of the floor. Why do they do this? For the joy of exploration.
Kids are instinctual strength training geniuses. If a child tries to pick up a watermelon, they squat down, wrap their arms around it (think atlas stone) and try to stand. If they can't move it, they may try again. If they still have no luck, they simply move on. They don't keep trying over and over until they hurt themselves. If they can pick it up, however, they take it for a stroll. They walk around with their heavy object - for a little while at least. Kids simply know how to build amazing strength. And we dont.
We should really consider approaching our strength training through the eyes of a child. Let's look at the squat for example. What if we trained the squat the way a child does: from the ground up. Think back to the watermelon example I used above. What kind of squat does this resemble? The Zercher deadlift/squat. It is the way a child would train the squat.
The Zercher squat is the perfect bulletproof squat. With the Zercher, it is hard to squat more weight than you can hold. It has a built in "safety" factor to it, thus lessening your chance of injury. Also, the Zercher reflexively engages your core. It zips you up without you having to mentally tighten your muscles. They just tighten up on their own. When you attempt a Zercher squat, your body becomes one solid muscle. This makes you really strong and "real world" strong.
If you really want to get strong, you could employ the Zercher the way a child does, you could lift your bar from the floor, take a walk with your weight for a certain distance and then repeat again. This will make your body strong enough to stop bullets, it is that tough.
Anyway, walk with the bar or not, in my opinion, the Zercher is the best way to squat - IF you simply want to be strong, healthy, and resilient. Those things are things that I want. If you want to be a powerlifter, then Zerchers may not be the best squat to train with. HOWEVER, they can certainly lay a solid foundation to perform back squats from.
Speaking of powerlifting, If you are not a powerlifter, do you really need to do back squats? Just a question, if you like back squats, great. Have at them. You'll never see a child do back squats though. I know, I am taking an idea to the extreme, but think about it anyway. And, while you think about that, also imagine how you will never see a child perform an overhead squat. ;)
Anyway, I really do think children do a lot of things very well and very right. Kids know how to train the squat. And, kids know how to become bulletproof. If becoming bulletproof resinates with you, Zerchers can be a great tool to use in that quest. They are kid tested and mother approved.