Originally posted by Zep Tepi:

That is the correct way to hold a spear if you are also holding a shield. The overhand grip puts it over your shield and out of the way.

If you want to look cool, get an atgeir instead. The spin attack followed by a stab works great against draugr and wolves.

Not that there aren't spear plays where you reverse into an overhand grip, but the vast majority are done underhand (even underhand while over the shoulder).