(notice the "head back" position)
I get a lot of questions about Mark Rippetoe's recommendation to look slightly downward when squatting. I haven't spoken to him about the point, but I understand the reason for his recommendation and agree. His chapter on squatting in Starting Strength is absolutely fantastic. I think it goes without saying that this is highly recommended reading.
I don't spend a lot of time with head position in the Squat Rx videos, but I do have some of my own opinions on the matter and touch on them in Squat Rx #4. Here are the main points:
When squatting, you want to keep the head "back". NOT hyperextending the neck and staring at the ceiling lights, but driving the head backward and the chin slightly tucked. I've tried it every which way, but I've always preferred looking straight ahead while squatting - everything else just makes me dizzy. I avoid squatting in front of a mirror at all costs, by the way.
(Chin forward but again, notice the "head back" position)
Head positioning is important because body positioning often follows the lead of the head. Proper technique cues will depend on what the trainee is doing. If the lumbar is flexing, they probably need to think "HEAD UP!" or "CHEST OUT!" during the lift. If they aren't using the hips (and using the lumbar and/or knees instead), they need to think "HIPS!".
Cued improperly or lacking experience, a lifter who drives the chin (or chest) skyward can force the hips forward prematurely, increasing knee flexion, and actually make things harder than normal - to bring this back to normal, and involve the posterior chain a useful cue is "(weight on/drive with) HEELS!".
Huh? So, what do I do with my head?Very simply, keep your head back and look where you are comfortable. The answer to all of this minutiae is practice. Novice squatters who are preoccupied with head positioning, posterior chain engagement, outward rotation of the hips, etc. will suffer from analysis paralysis. Practice, a lot of weight and volume, and occasional technical polishing, will work out the fine nuances, including head positioning.