-Give them a "theory exam" before putting them in the military. Legendary+5 record keeper ought to do.
-Use an obsidian farm to make them legendary miners, engravers and masons as well without requiring a huge map. Legendary stone crafter and mechanic is also a bonus so they can make their own obsidian blades.
-Put the butcher shop in the barracks, screw miasma, we got waterfalls against that.
-AFAIK you gain armor skill by falling off things(atleast adventurers do) so station them on a bridge at z-1 and have somebody spam the related lever.
-Make them swim for better effects, careful not to drown them.
-pump operating, as said before.
-Their first taste of combat comes from hunting deer released in an old stripmine. They will try to ambush the target and if you pair them up with a bogged down recruit, they will chase after it forever untill you deselect the hunting labor and undraft the noisemaker.
-Next, give them an axe and send them out in the woods, preferably underground ones.
-Have them work on the farms in their spare time.
-Train them as siege operators, marksdwarves and wrestlers, in that order.
-Only then you give them an XXwooden weaponXX(put it on fire and dump it in water when it reaches the desired % of charcoal) and let them fight against captive animals untill you run out so they aren't dabbling anymore when they realy start to spar.
That ought to reduce injuries.