The Reactive Virtual Trainer

In this masters project, we set out to improve interaction of the virtual trainer with users. The goal was a trainer that supports a user with his workout goals like a real sports trainer: assist technically with an exercise and motivate the user to keep working hard. From this broad goal we have picked two main topics: we tried to make users perform exercises at a speci�ed intensity and we have worked on motivating users by adjusting the feedback the trainer gives. We have developed and implemented a software architecture for the virtual trainer, and evaluated our work with the prototype. Challenging a user with an exercise and motivating users during a workout are perhaps the most important tasks of a sports trainer. Working out at di�erent intensities gives di�erent training results: For example increased stamina or increased strength. Usually a human sports trainer looks at the users training goals and level of �ttness to compile a workout that challenges the user and lets him achieve his goal. Many people sport not purely for fun, but to achieve some goal: For example lose weight or to be healthy. Those people sometimes rely on peers or the sports trainer for motivation. To challenge a user, we started with two basic ideas: Performing an exercise faster is more intense and an exercise is most challenging when done at the optimal intensity. The trainer moves faster or slower, with the intention that the user picks up the change in speed. We measured the exercise speed using a wiimote and we measured the intensity using a heartrate sensor. The evaluations showed that our prototype can in uence the users speed in an intuitive way. To make users work out at a speci�c (optimal) intensity needs some more work, because the intensity of an exercise di�ers for each user. Regarding motivation, we have applied aspects of several psychological models of motivation, politeness and mood to the virtual trainer. The trainer has a mood that is in uenced by the users performance and the trainer chooses feedback of varying politeness, depending on that mood. We made videos of a baseline trainer and two trainer versions with motivational enhancements. We have showed these videos to users and asked them to compare the trainer versions on various aspects in a questionnaire. Participants found the rude trainer and the friendly trainer more motivating than the baseline, the motivational factors competency and relatedness were rated higher. Participants found the rude trainer and the friendly trainer assisted them better. The rude trainer and the friendly trainer scored higher for positive character traits and the baseline trainer scored highest on negative character traits. We have developed a software architecture for this project, looking at previous work in this area of software design. We have used a multi agent approach, where multiple agents generate behavior in parallel. The design has performed well, we did not encounter major issues, any changes needed during implementation �t in with the original design. This project results in a system that intuitively in uences the speed at which a user performs an exercise. Previous work only in uenced users verbally. The other contribution is a trainer with aspects of several psychological models for generating feedback, which is new for virtual sports trainers. Finally, we have designed and implemented a software architecture for a sports trainer application. Future work could develop a system to optimally challenge a user during a workout or build on our results to better motivate users.