Index of Difficulty between Multiple Joint Movements Using Fitts Law

Fitts Law has become an important tool in the design of Human Computer Interface (HCI). It predicts the time required to move to an object given the distance to the object's center and its size. Over the years, Fitts law has been tested on various single joints such as the elbow, wrist, and finger In order to broaden the applicability of the law to more complex tasks, we propose to extend Fitts law to model the movement of multiple joints. We show experimental results indicating that Fitts law can indeed be usefully extended for multiple joints, The new law creates a valuable metric in the design of efficient human-robot-interaction, prosthetic limb-controllers, physiotherapeutic exercises, sports equipment and HCI.