Immersive Virtual Reality-Based Exercise Intervention and Its Impact on Strength and Body Composition in Adults with Down Syndrome: Insights from the InDown Pilot Project

This pilot study examined the feasibility, usability, and physiological effects of a high-intensity exercise program delivered through immersive virtual reality (IVR) in adults with Down syndrome (DS). Twenty participants (mean age: 29.85 ± 9.37 years) completed a 12-week intervention using the FitXR exergame on Meta Quest 3, with two sessions per week. Usability, safety, and personal experiences were assessed via the System Usability Scale (SUS), Simulator Sickness Questionnaire (SSQ), and Game Experience Questionnaire (GEQ), while body composition and strength were measured using bioelectrical impedance analysis and standardized tests (handgrip dynamometry, Five Sit-to-Stand Test). Results indicated excellent usability (SUS: 92.88–95.03/100), minimal cybersickness (SSQ: 2.12 → 1.98/48), and high adherence (90%). Positive experiences increased significantly, with no negative experiences reported. Lower-limb strength has been considered as a primary outcome, which has shown to improve significantly (p = 0.018; Cohen’s d = 0.89), whereas upper-limb strength and body composition changes were minimal. These findings suggest that IVR-based exercise is a safe, engaging, and feasible strategy for promoting physical activity and enhancing functional strength in adults with DS. Further controlled trials with longer duration and nutritional strategies are warranted to optimize body composition outcomes.