As I know, armour user is used to make dwarves move faster while wearing armour, very useful for dwarves in full steel for example. It is trained primarily through the dwarf letting his armour absorb the hit, which begins to become problematic for elite dwarves who can parry and block most attacks through sparring or live combat with ease. After seeing Skullsploder's ingenious barrack design in the Ultimate Melee Dwarves thread, which involved the dwarf falling down 2 z levels when they dodged during sparring, so the impact itself would give some armour user skill. I applied this to my current fort, and it was worked decently well although it delayed sparring a bit it didn't matter since they were already at the peak of their ability in most other skills (Axedwarf, Shield User). For fun, I decided to just give them each 2 master work wooden shields to perhaps train misc object user on the way (useless in fort mode usually, but I thought it would help their shield bash when they are in live combat). Now, I forgot about this and believed them to be having a master work steel battle axe, so regularly sent them to kill an isolated human soldier, which is where it gets weird. As expected, once the human was subdued I checked the reports and they were hilariously bashing him in the head with their wooden shields, which was deflected by his bronze helm. But during this, they were
actively gaining armour user at a hugely rapid rate, going from Great to Master in
mere minutes of bashing him in the head with wooden shields. They are gaining armour user skill as I speak. Is this common knowledge? When I searched up dual wielding shields on the forums, I didn't get anything mentioning this.
Edit: Both my axe lords are legendary armour user right now, from great armour user. They are gaining quite literally hundreds of EXP from just bashing the human with their shield, almost as fast as Danger Room gaining speeds.
Picture of the report for clarity:
Yes, that is 29 pages of shield bashing. Within the first page he was incapitated by a kick to shin, although it is more than 29 pages but the combat reports just reset due to how long ago and how many pages there are.