I just started another fort to test something and took four of my first migrant wave and recruited them. They all were zero skill in all military categories. I set them all to train continually. Before spring had arrived they were at 4 (less than 100 xp from 5), 5, 5 and 6 in spear, 8+ in fighter, and 2 to 4 in sheild. They were equipped with iron spears and wooden sheilds from the start, and I added leather boots and gloves as I acquired the materials.
Assuming things work as it did in my last .25 fort, and so far it appears to be doing so, I expect all four of these dwarves to hit Spearmaster by the beginning of the third year of the fort. In my last fort I had five dwarves that survived a fight against 32 elves (half sword, half bow), 8 war bears, 6 crossbow gobs and 6 macegobs with the only injury coming from the recruit that "found" the orcs while off duty just after I stopped the alert due to the elven ambush. The newst recruit of the six took an (un)lucky shot to teh face and died instantly, while his recruit partner almost lasted long enough for his captain to get to him and save him from getting his head pounded for the fourth and final time, leaving me with four basically unhurt spearmasters (i think one had a bruised leg) and two dead newbs.
Basically, use squads of 2 to 5 dwarves on constant training for six months to a year, after which point actual combat experience will give them better training. Stopping training to kill larger animals, as suggested above, will definitely help.
And, of course, you could always set up a danger room if you don't want to wait two or three game years for your troops to reach legendary.