Ok, there is a lot of good and bad information in this thread, and as someone who has been around since weightlifting shoes started going "mainstream" I'd like to step in and clear a few things up.
Firstly, there is absolutely NOTHING wrong with going butt to ground (aka ATG) when squatting. As a matter of fact, the increased range of motion insures that you work your entire posterior chain. The myth that this is bad on your knees seems to have permeated the fitness world by word of mouth and ignorant doctors. The fact is, if you are using a controlled descent then your knees and the tendons/muscles around them will strengthen and you should have no issue going ATG. The folks that develop knee issue from squats usually have poor form or do silly "dive-bomb" style squats when they hit the bottom portion of the lift as fast they can with hopes that tight hip flexors will "spring" them back out of the hole and past any sticking point - now that is bad for the knees!
As for weightlifting shoes, keep in mind there are different styles of lifting weights. For simplicity we will stick with the main two: Olympic weightlifting and Power Lifting. Both styles require a different type of shoe because the mechanics used are different. Olympic weightlifting requires explosive movement and quick descent under the bar.
Let's take the Olympic clean and jerk for example. A raised heel shoe allows one to drop very low, possibly below what they could achieve without a heel, with less stress on the knee. This allows you to "catch" the bar easier when performing the clean. Since you can drop under the bar faster and lower, you do not need to bring the weight as height during the triple extension phase (lifting the weight off the ground).
Now with a high-bar squat, commonly referred to as an Olympic squat, you typically drop your butt straight down. This keeps the bar inline with your heels - if your try to stick your butt out your feel like you are falling forward and you begin to strain your back. This forward lean or "dump" you feel becomes more emphasized the heavier the load gets. A raised heel shoe in this situation allows you to "sit-back" in your squat, removing some of the forward lean you feel. It seems counter-intuitive that a raised heel would prevent your from feeling as though you are being pushed forward, but in actuality the heel changes your mechanics and forces you to arch back with your shoulders, tighten your core and flare your knees a bit - correcting your squat form.
With power lifting the obvious goal is to just move as much weight as possible. The ranges of motion are usually much shorter and power lifters go out of their way to decrease the ROM even greater by using wider stances and a wider grip for benching. The common power lift squat makes use of what is known as low-bar squatting. The bar is placed as far down the traps as comfortable for the lifter - this takes the forward lean issue out of the equation because now the bar is perfectly in line with the heels of the feet.
The low-bar squat requires a lot of core strength and puts more emphasis on the posterior chain, especially the glutes and hams, over the quad muscles. The introduction of a raised heel shoe with a low bar squat is somewhat counter-productive in this situation. I'm tired of typing, but I think you get the point. There's more info over at weightlifting shoe resource if you are interested.
The only time I've ever seriously hurt myself in the gym is when I decided to deadlift 585 pounds barefoot. I barely noticed it at the time, but I walked around with what felt like a broken foot for nearly a month before finally going to a podiatrist where I was diagnosed with a Lisfranc fracture and some kind of tweak in my extensor digitorum brevis.
I go barefoot when I'm going light but it's Chuck's for me when going heavy.
Trust me, it's not worth this type of injury when powerlifting.
I began this Primal journey on December 30th, 2009 and in that time I've lost over 80 LBS and more than 35 inches.
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^ I'm not so sure if wearing shoes would have protected you from that fracture ... do weightlifting shoes have arch support?
I've squatted up to 400lbs using Five Fingers. Shoes with a heel will make it easier to squat heavier but are not required.
@Abu - I don't see how lifting shoes would "position your knee" any better than could be done in any other shoe/unshoe. Knee position is all about foot positioning
I didn't like the rules you gave me, so I made some of my own.
Strong people are harder to kill than weak people, and more useful in general. - Mark Rippetoe
I lift barefoot and I've seen video of Paul Anderson lifting barefoot too (it's primal). The 20 reps squatting is usually used for weight gaining, which I'm assuming isn't you goal. I use 3 sets of 5 and recently gained the strength to be able to squat 300 pounds, so maybe it would work for you. I'm 6'2'' and a lean 185 pounds.
Paul Anderson lifted way more weight and he managed to do it barefoot.The only time I've ever seriously hurt myself in the gym is when I decided to deadlift 585 pounds barefoot. I barely noticed it at the time, but I walked around with what felt like a broken foot for nearly a month before finally going to a podiatrist where I was diagnosed with a Lisfranc fracture and some kind of tweak in my extensor digitorum brevis.
I go barefoot when I'm going light but it's Chuck's for me when going heavy.
Trust me, it's not worth this type of injury when powerlifting.