The wear pattern on my Brooks Glycerin 17 shows that the heel section wore out more than the fore-foot, so I am a heel striker.  There are indications from the sole usage pattern of over-pronation, as well.  The net impact of this uneven and worn parts of my Brooks Glycerin 17 caused extremely severe pain in my sciatic nerve, which was alleviated with our BIG Relief with✛K✛™ but, a few days later, I had to buy new running shoes.