Quote - Perhaps I'm wrong here, but from my understanding, in order to do motion capture, you need sensors attached to a moving subject in order to input the motion data.  Such systems are extremely expensive./quote]

Some motion capture apps use tracking (kinda like AE's tracking method).  So, ping pong balls on a black suit, which provides the needed contrast to allow the tracker to adequately capture the motion, but definitely, using sensors or even better, a "tracking suit" is the popular method in the industry.