If you've ever played a Kinect game, you'll know that sometimes it can be difficult to work out exactly where to move your body. Researchers from Microsoft and the Department of Computer Science at the University of Illinois have created a prototype system called LightGuide that could help with that and more besides — it projects visual feedback onto users' arms to help teach them correct movements for a variety of tasks. For example, an amateur martial arts trainee could be instructed by the system exactly how far to extend his or her arm while punching so as best to avoid injury.

LightGuide uses the Kinect camera to track an arm in 3D space, and visual cues such as arrows and shadows are projected onto it to help guide the user's movements. The researchers found that users were able to perform various actions significantly faster after training with the new system, and say they want to extend the concept to other parts of the body.