I think I alreadyRegine blogged about Kick-ass Kung-Fu last year. It's a mixed reality game that merges virtual and real worlds to let players control a Kung-Fu game with their movements.

What is interesting is that, the designers conducted some studies about its usage:, 46 persons tried the system: Hämäläinen, P., Ilmonen, T., Höysniemi, J., Lindholm, M. & Nykänen, A. (2005). Martial Arts in Artificial Reality. In Proceedings of Conference of Human Factors in Computing Systems (CHI 2005), 2-7 April 2005, Portland, Oregon, USA.

Various factors are studied. However the most interesting investigation is certainly the motion exageration which seems to be an intriguing factor to investigate. I guess it might contribute to the 'fun' of the game.

According to our experience, Kick Ass Kung-Fu can augment and motivate martial arts and acrobatics training, at least at beginner and intermediate levels. For more advanced technique and combat training, the users wanted the game to be more realistic. Our low-level computer vision system allows multiple players and practically all weapons, but in the future, we will consider model based computer vision for increased realism. Using a skeleton model would enable you to block attacks and interact more realistically with the virtual environment. However, realism poses challenges in interaction design as well as technology, since it is nontrivial to control an avatar that reacts to the environment. Currently, the mapping between the user and the avatar is one-to-one, except with respect to vertical position. The mapping breaks if the avatar can trip over virtual obstacles without real-world counterparts, or if impact forces are applied to the avatar.

Although motion exaggeration was found fun in the game, many experienced martial artists requested a training mode with realistic motion and enemies.The Kick Ass Kung-Fu user interface can be considered to develop motor skills and fitness, but from an educational point of view, this is only part of the experience.