It depends on what program you're using - are you using MED? Just my personal opinion, but MED is absolutely terrible for designing/animating models in...I might look into something better suited for animating. I use Milkshape which is pretty good and fairly cheap, and I hear Blender is excellent, though I don't use it myself. I know there are some great animation tutorials for Milkshape, and I bet there are for blender too.