PUB - Publikationen an der Universität Bielefeld

Even though positive effects of being physically active are commonly known, only a few parts of the world population are sufficiently ac- tive. The World Health Organization (WHO) states that this problem affects 31% of the adult’s world population and 80% of the adolescent population. Appropriate levels of physical activity (PA) are essential to prevent obesity in childhood and to keep a Quality of Life (QOL) in old age but are also essential to prevent other Noncommunicable Diseases (NCDs). Thus, physical inactivity is growing into a severe problem globally, and there is a growing need to motivate people to become more physically active during their lifetime. One primary cause that raises PA levels is having a peer or help from professionals. However, having assistance is not possible in every situation. It might be challenging to find and schedule with a partner or to commute to other places. Roboticist introduced Socially Assistive Robot (SAR) as an assistive tool for exercising, cognitive or rehabilitation tasks. This thesis explores SAR in the context of exercising along four features that have been partly targeted but not yet thoroughly investigated. These features are a) the social role of the robot, b) encouragement c) embodiment and d) adaptation. First, this thesis looks at the mo- tivational effects of exercising with SAR concerning features a) - c). Second, this thesis questions how a system can adapt to the user, and whether adaptivity or adaptability is enough to close the gap between user needs and system behavior. I conducted studies that test the dif- ferent features by assessing subjective ratings of the robot as well as measurable motivational variables (e.g., time spent exercising with the robot) in a bodyweight workout scenario. The results show that features a) - c) have a positive influence on user’s exercising time. Additionally, users perceive a robot compan- ion as more likable than a robot instructor or a human partner. Fur- thermore, an adaptive robot increases the associated competence and quality of relationship compared to an adaptable robot. However, the results also show that the robot does not always have to exercise along with the user. In situations where it is not possible, the robot could also only give encouraging feedback. This thesis backs up earlier find- ings of using SAR by replicating motivational group exercising ef- fects found in Human-Human Interaction (HHI). Thus, the evidence that SARs are a suitable tool for rehabilitative interventions increases which may convince health experts to consider SAR as a useful thera- peutic tool. Nevertheless, this thesis evaluated the effects only during short-term interactions. Thus, proving that the found effects are long- lasting is essential for future studies.