Optimizing sedentary interaction surfaces: A biomechanical framework for multifactorial ergonomic design

This study investigates the biomechanical effects of backrest inclination angles (0°, 10°, 20°) during prolonged sitting, aiming to establish evidence-based ergonomic design guidelines. A 3-hour standardized office protocol integrated surface electromyography (sEMG), interface pressure mapping, and validated subjective questionnaires to comprehensively assess neuromuscular activity, pressure distribution, and temporal effects on BP neural network-based comfort prediction models. Statistical analyses revealed significant postural fatigue accumulation, particularly in weight-bearing regions (gluteal, lumbar, and femoral areas). Distinct angle-dependent neuromuscular adaptations were observed: trapezius and biceps femoris exhibited fatigue patterns at 0°/20°, contrasting with recovery patterns in biceps femoris/gastrocnemius complex (10°), rectus abdominis activation (0°), and erector spinae recruitment (20°). The temporal-integrated prediction model demonstrated superior performance, reducing mean square error by 23.19% (shoulder), 42.34% (lumbar), 68.44% (biceps femoris), and 76.34% (gastrocnemius) compared to non-temporal models. These findings establish a quantitative framework for understanding muscle-specific postural adaptation mechanisms, confirming the critical influence of temporal factors and inclination angles on neuromuscular responses. By emphasizing the necessity of multifactorial optimization integrating biomechanical and perceptual metrics, this research advances ergonomic design principles, refines seating comfort prediction algorithms, and provides clinically relevant solutions for preventing occupational musculoskeletal disorders associated with prolonged sitting.