This talk will look at how Virtual Reality technology can be used to understand and improve movement performance in both sport and health related contexts. The first part will look at how the theory of perception/action coupling can explain why this technology is useful, by focusing on how information picked up by our senses is used by our brains to guide our action-based decisions. The second part will look at concrete examples of how this technology has been used to study decision making in sport. By manipulating the visual information presented to the brain in the virtual world and by measuring when and how the participant responds in the real world, new insights into players' decision-making abilities, including expert/novice differences, have been obtained. By capitalizing on the versatility of this technology, examples of how it has been used in health-related context will also be shown (gait in people with Parkinson's, balance in older adults). The third and final part will explore the benefits of applying this kind of technology in applied settings (sports performance and rehabilitation).