Theory and Principles
Theory and Principles give a structure to design and development. Without the underlying theory, which has been developed and added to over many years, the designer or developer is only guessing. Pure intuition can only take you so far. Principles, Elements, and underlying theory are our keystones to quality in design and development. And while some of these fields of theory may at first seem not to apply to a study of interactivity and game-based learning, I hope to demonstrate that there is in fact a rich tapestry of dependency that connects them all.
But such lofty goals will have to wait; for now, here are two offerings that may be of interest, animation and biomechanics.
In the case of animation, the original 12 principles of animation as codified by Disney help give moving pictures a sense of life. These were the principles an entire industry was established upon. But over time, more prinples of animation were developed, which I will refer to as the extended principles of animation, and the physics of animation. Each of these, if incorporated into your work, will improve the final result.
The way living things move is important not only when we want to recreate them in digital art or animation, but many new solutions and products come from studying biomechanical movement of bipeds, quadrapeds, birds, and insects. While this page does not exactly present a theory of biomechanics, it does have many useful resources that may help you understand the movement you are interested in.