Stand Up, Head Up, Stretch Up: Exploring Opportunities for Context-Aware Adaptive Stretching in MR for Microbreaks among Sedentary Workers

Prolonged desk work has become a major source of musculoskeletal strain, leading to fatigue, discomfort, and reduced mobility among sedentary professionals. Although prior interventions such as standing desks and exergames promote movement, most overlook cumulative postural imbalance and environmental constraints that shape ergonomic risk. We present Adaptive Stretching Pipeline (ASP), a mixed-reality (MR) system that delivers personalized stretching guidance during work breaks. ASP continuously monitors posture through joint-angle and duration analysis and leverages a vision-language model (VLM) to assess workspace supports such as desks or walls. Based on an integrated need-scoring model, the system generates adaptive MR stretching sessions targeting fatigued body regions during microbreak. A three-phase formative study informed the system design, including expert interviews on clinical stretching practices, workplace observations to identify environmental supports, and stretch video analysis to construct a stretching library. A user study with 15 participants compared ASP to a Bend and randomised condition. Our results provide initial evidence that such adaptive mechanisms can shape perceived effort, engagement, and time perception in short-term interactions.