Toward a multidimensional fitness paradigm: a critical review and agenda for science, practice, and policy

This study aims to critically re-evaluate classical definitions of physical fitness proposed by leading institutions such as the American College of Sports Medicine (ACSM), the World Health Organization (WHO), and the National Academy of Sports Medicine (NASM). Despite their physiological robustness, these definitions no longer capture the multidimensional determinants of human functionality in modern life. The paper introduces a multidimensional fitness paradigm that reframes fitness as a biopsychosocio-emotional capacity integrating physical, mental, social, occupational, and digital dimensions. A narrative critical review of transdisciplinary literature was conducted across the fields of behavioral science, social epidemiology, occupational health, and digital medicine. Conceptual, methodological, and operational gaps in existing frameworks were identified and critically appraised. Drawing from the biopsychosocial model, self-determination theory, behavior change frameworks (COM-B), and digital ethics literature, the study synthesized theoretical foundations and proposed measurable indicators for five interacting dimensions of fitness. Cross-cutting themes such as equity, ethics, data governance, and cultural variability were analyzed to ensure applicability across diverse populations. The review reveals that traditional physiological metrics-such as cardiorespiratory endurance, strength, and body composition-are necessary but insufficient to account for overall human functioning. Evidence demonstrates that cognitive control, emotion regulation, social connectedness, occupational balance, and digital literacy substantially influence wellbeing, resilience, and sustainable performance. The proposed multidimensional model operationalizes fitness through integrated indicators and suggests a validation roadmap encompassing reliability, validity, feasibility, and fairness. Furthermore, illustrative applications in clinical, workplace, and municipal contexts demonstrate how multidimensional fitness can guide personalized interventions and policy innovations. The multidimensional fitness paradigm expands the conceptual boundaries of fitness from a purely physiological construct to an integrative biopsychosocio-digital framework. By embedding ethical, cultural, and technological considerations, it offers a roadmap for 21st-century health promotion and sustainable performance. The study concludes with a 10-point research and policy agenda emphasizing equity, data ethics, and cross-sectoral integration, positioning fitness as both a scientific construct and a societal compass for human flourishing. The framework is presented as a conceptual proposal: its structure, indicators, and applications remain to be empirically validated.