eng Science and Education Publishing American Journal of Sports Science and Medicine 2333-4606 2020-06-23 8 1 23 35 10.12691/ajssm-8-1-5 AJSSM2020815 article Michael Ora Powell mopowell@ucsc.edu 1 Aviv Elor 2 Mircea Teodorescu 2 Sri Kurniawan 2 Department of Electrical and Computer Engineering, University of California - Santa Cruz, Santa Cruz, CA, USA Department of Computational Media, University of California - Santa Cruz, Santa Cruz, CA, USA Upper limb injury often requires repetitive and long-term physical rehabilitation which can result in low adherence due to the repetitive and internally motivated nature of the exercises. Immersive Virtual Reality (iVR) systems enhanced with games can address these challenges. These systems provide a platform for adaptable sensing and analytical tools to track progress, personalize therapy, and increase long term engagement. This paper explores such a system, through an iVR-based experience for upper-extremity rehabilitation called ¡°OpenButterfly,¡± where users follow movements to protect a virtual butterfly. OpenButterfly enables a dynamically controllable environment for individual exercise by utilizing motion capture, a biomechanical model of torque and angular momentum, and a biometric pipeline for brainwave, heartrate, and skin conductance analysis. We examine this experience for five adult users with varying degrees of injury over the course of eight weeks. Our results suggest that experiences like OpenButterfly provide strong platforms for long-term physical therapy engagement, analysis, and recovery. Lastly, this paper concludes with considerations for future research into adaptive iVR physio-rehabilitation. http://pubs.sciepub.com/ajssm/8/1/5/ajssm-8-1-5.pdf virtual reality biofeedback biomechanical simulation OpenSim rehabilitation exergame serious games