On Oblivion
Heavy Armor determines how much heavy armor protects you and how fast it degrades. Heavy Armor includes iron, steel, dwarven, orcish, ebony, and daedric, in order of effectiveness, least to greatest. Heavy Armor is governed by Endurance and is a Combat skill
here is the available heavy armor though out the game
available at level 1
iron helm iron boots iron gauntlets iron greaves iron cuirass iron shield
available at level 3
steel helm steel boots steel gauntlets steel greaves steel cuirass steel shield
available at level 6 dwarvan helm dwarvan boots dwarvan gauntlets dwarvan greaves dwarvan cuirass dwarvan shield
available at level 10 orcish helm oricsh boots orcish gauntlets orcish greaves orcish cuirass orcish shield
available at level 15 ebony helm ebony boots ebony gauntlets ebony greaves ebony cuirass ebony shield
available at level 20
daedric helm daedric boots daedric gauntlets daedric greaves daedric cuirass daedric shield
blade helm blade boots blade greaves blade cuirass
leagon helm leagon boots leagon greaves leagon cuirass leagon shield
 Skill Perks
At Novice, armor degrades 1.5 times as fast.
At Apprentice, armor degrades normally.
At Journeyman, armor degrades 50% slower.
At Expert, EQUIPPED armor loses half of its weight, letting you move faster and carry more.
At Master, EQUIPPED armor weighs nothing
You gain 1.25 experience points for every hit you take while wearing heavy armor.
- The easiest way to train is to simply let enemies hit you while wearing heavy armor. Put the difficulty slider down to it's lowest level, get a good Restoration spell to hand and you can let enemies hit you over and over for as long as you like.
- Find a decent summoning spell. Use it and attack your summoned monster three times(preferably with the weakest weapon available you can find, so you don't kill it) and then let it hit away at you while you take it's attacks. If you've completed the Recommendation quests in the Mages Guild then you should create a custom summoning spell with the weakest magnitude but the longest duration. This is good for Conjuration training as well.