That's always going to be the challenge with a real-time motion system, to track the motion and keep the animation on the body believable. That was actually one of the technologies that Microsoft built, this idea of mapping the physical motion that you are doing to the actual motion you want the Avatar to display.
It doesn't always look how you expect. In other words, when you see someone throw a baseball, you've seen it hundreds of times before on TV, so you know how it should really look. Well, we aren't all professional baseball players. How many times have you heard someone say, "Oh, he throws like a girl!" Because there's some really weird, very simple motion or something. Now you don't want to see your character doing that, instead you want to see your character being the best pitcher in the major leagues. And that's one of things it can do, it can map that.
You can actually have the arm do a realistic motion of what you are doing, while the body goes through an animated, or procedural animation. We have that system in Unreal where you can blend different animations, so you can have a ragdoll effect on a leg, a running animation on an arm, a turning animation on the head. Microsoft has taken that one step further and does the mapping as well. So you can have a part of the body that's mapped, whereas another part is procedural.
