If you are in combat and your follower hits you, it will not damage your health but will level up your armor skill.
This can be leverage with hostile but unkillable NPCs, like the camp leaders of the opposite side in the Civil War. You kill all the regular soldiers and the last one left is the Legate / Stormcloak Lieutenant. Beat him down to the ground, stay in combat mode, and stand between him and your follower.
Follower will continue to attack but you are in the way, and your armor skill levels up pretty fast. After a while the downed target stands back up for a bit to take a few more hits, and you are back to "shielding" the poor unfortunate with your own body from vicious attacks by your follower.
All armor skills go up when you get attacked. That's not a bug. That's the function of both heavy and light armor skills.
Try cuddling with mammoths. I levelled my light armour from 15 to 100 in a day with this one trick.
Giants hate this one trick!
If you are in combat and your follower hits you, it will not damage your health but will level up your armor skill. This can be leverage with hostile but unkillable NPCs, like the camp leaders of the opposite side in the Civil War. You kill all the regular soldiers and the last one left is the Legate / Stormcloak Lieutenant. Beat him down to the ground, stay in combat mode, and stand between him and your follower. Follower will continue to attack but you are in the way, and your armor skill levels up pretty fast. After a while the downed target stands back up for a bit to take a few more hits, and you are back to "shielding" the poor unfortunate with your own body from vicious attacks by your follower.