  Fitts' law is a fundamental tool in measuring the capacity of the human motor
system. However, it is, by definition, limited to aimed movements toward
spatially expanded targets. We revisit its information-theoretic basis with the
goal of generalizing it into unconstrained trained movement such as dance and
sports. The proposed new measure is based on a subject's ability to accurately
reproduce a complex movement pattern. We demonstrate our framework using
motion-capture data from professional dance performances.
