The Impact of Performance-Specific Feedback from a Virtual Coach in a Virtual Reality Exercise Application

Virtual reality (VR) exercise applications are promising tools, e.g., for at-home training and rehabilitation. However, existing applications vary significantly in key design choices such as environments, embodiment, and virtual coaching, making it difficult to derive clear design guidelines. A prominent design choice is the use of embodied virtual coaches, which guide user interaction and provide feedback. In a user study with 76 participants, we investigated how different levels of performance specificity in feedback from an embodied virtual coach affect intermediate factors, such as VR experience, motivation, and coach perception. Participants performed lower-body movement exercises, i.e., Leg Raises and Knee Extensions, commonly used in knee rehabilitation. We found that highly performance-specific feedback led to higher scores compared to medium specificity for perceived realism, as well as the anthropomorphism and sympathy of the virtual coach, but did not affect motivation. Based on our findings, we propose the design suggestion to include precise, performance-specific details when creating feedback for a virtual coach. We observed a descriptive pattern of higher scores in the low specificity condition compared to the medium condition on most measures, which raises the possibility that less specific feedback may, in some cases, be perceived more positively than moderately specific feedback. These findings provide valuable insights into how design choices impact relevant intermediate factors that are crucial for maximizing both workout effectiveness and the quality of the virtual coaching experience.