Was reading Gérard Vroomen's blog recently and thought of this thread. He has four recent posts that might help out some of us here (links below). Now before anyone goes and reads them and starts saying this is even more counter-intuitive as he suggests that lowering bar height isn't always the best, hear me out. I think that this thread and Vroomen are getting at the same thing, that much of your positioning on the bike comes from the core. Lowering bars just to slam your stem isn't going to help if you aren't focused on your body positioning (flat back, rotated pelvis, more aggressive posture, etc.) and your core (keeping elbows bent, weight off hands, etc.)
I recently lowered my bars about an inch but didn't focus on my core positioning because I thought it would all just come. Needless to say I was pretty much the same as before, my butt hurt, my hands got sore, and I wasn't using the proper muscle groups in my legs. Not to mention my elbows were locked and my handling suffered because rather than compensating for the lower bars with my body I just extended my arms. The last couple of days I've been focused on rotating forward and keeping my elbows bent and I feel much better on the bike.
Great thread all!
arm positioning pt. 1
arm postioning pt. 2
Body positioning vs bar height pt. 1
Body positioning vs bar height pt. 2
Edit: I'll throw this link in as well for
core exercises