So I take it the best way to train heavy armor is let myself get hit? Can I level it up relatively fast by having a weak enemy (wolf or that big rat) hit me constantly?
Well, that's how I've gotten some Heavy armor points
Just let a bandit hit you for 2% of your HP for a long time. However, I'm almost positive that the harder the enemy the faster it goes up. I remember getting +1 to blocking, heavy armor and 1h when fighting a giant.
Would make sense for it to be "the more damage you take, the faster you level"...