Sure it works, but you need to heal them as well (tip: you can train your healing skill as well). You should also you a low damage weapon (i.e. no DI on your suit or weapon).
Personally I prefer Despise for training my warriors. Level 1 (Lizardmen) is great for getting to 60 or 70 in Melee, Anatomy, and Tactics. Level 2 (Ettins and Earth Elementals) is perfect for training to around 90 or 95. The Third level (Ogres and specifically Ogre Lords) can take you all the way to 120, though I normally switch to Stone Harpies at 110 and Daemons at 115.
