squat help please

[f=ma]

I squat close stance, olympic, high bar style. I'm just doing my own pyramiding 5x5 right now and currently acclimating into my program. meaning that I am working with lighter weights for the next 2-3 weeks (relatively speaking, of course). I tried a slightly difference stance today which I love. it is feet slightly closer than shoulder width, toes 15 degrees outward or so. with light weight (for me), i am perfectly upright, tight core, arched lower back with my ass on my calves..

so I tried a few reps at slightly higher than this weeks scheduled working weight just to feel the difference stance out with tougher weight and it was immediately apparent that my hips are coming up in my ascent before they should, causing me to lose my upright position.. its certainly not turning into a GM but i want to improve. is there any kind of suggested assistance I can add to my routine to keep my form the way it should be? thanks.. sorry if this is a dumb question.

edit: i want to add that I have outstanding ham/glute/hip flexibility which i work on EOD and i dont think that is part of my prob

[slashkills]

You can do good mornings, sumo sldl, and snatch grip deads. Anything that strengthens your back will help. Id say though that a little bit of lean is common and ok. If your being honest with yourself and its not turning into a goodmorning then you are probably fine.

[mastermonster]

If your goal is bodybuilding or olympic lifting your extreme narrow stance is probably OK to stay with. If powerlifting is your goal you'll probably need to start widening your stance out to some degree, wheather you want to compete raw, equipped, monolift or walked out. For most that extreme narrow stance is not going to give you your best potential for a huge squat. As you try to get heavier and heavier you will probably see these problems amplify. Widening out will make it much easier to stay upright. It also incorporates other large muscles as primary movers such as the hams and glutes as well as the adductors. Narrow, these are not nearly as envolved and it is more of a quad move. As mentioned if your goal is not powerlifting your narrow stance may suit your goals more. You probably won't be doing heavy singles, doubles or triples as a bodybuilder. It just depends on what you want from the squat. Good luck whatever your goals are!