Aging or sedentary behavior can decrease motor capabilities causing a loss of autonomy. Prevention or re-adaptation programs that involve practice of physical activities can be precious tools to fight against this phenomenon. “Serious” video game have the potential to help people to train their body mainly due to the immersion of the participant in a motivating interaction with virtual environments. We propose here to discuss the results of a preliminary study that evaluated a training program using the well-known WiiFit game and Wii balance board device in participants of different ages. Our results showed that participants were satisfied with the program and that they progressed in their level of performance. The most important observation of this study, however was that the presence of a real human coach is necessary in particular for senior participants, for security reasons but also to help them to deal with difficulties with immersive situations.