Beyond injury prevention: an iterative cycle architecture for musculoskeletal health and quality of life in sedentary adults

Abstract

The article addresses the gap between existing physical activity programming models and the needs of sedentary adults with musculoskeletal dysfunction and reduced health-related quality of life (HRQoL). The study aims to develop and substantiate an iterative cycle architecture integrating the PDCA model, Just-in-Time Adaptive Interventions (JITAI), and Self-Determination Theory (SDT), and to evaluate its feasibility through a 12-week intervention with a 3-month follow-up. A critical analysis of three established frameworks – classical periodization, FITT-based prescription, and JITAI – reveals that none fully addresses the programming challenge for this population: periodization lacks adaptability, FITT has no responsive adjustment mechanism, and JITAI operates without program-level architecture. The proposed iterative cycle fills this gap through four interconnected stages – assessment, individualized design, monitored implementation, and data-driven adjustment – repeated every two weeks. The intervention involved 27 sedentary adults and combined aerobic, resistance, stabilization, and proprioceptive training at 50–60% HRmax, monitored via accelerometry and training diaries. Post-intervention results showed significant improvements in posture, back muscle endurance, static balance, and pain, with gains maintained and in some domains – dynamic balance and joint mobility – continued to develop at the 3-month follow-up. A key theoretical contribution is the formal integration of SDT indicators into load prescription logic, treating motivational readiness as a structural determinant of program progression. The iterative cycle is proposed as a reproducible mid-range programming model applicable in rehabilitation, fitness, and health-promotion settings.