24-hour Movement Behaviour study-Lithuanian protocol: a comprehensive overview of behaviours and health outcomes in adolescents.

The 24-hour Movement Behaviour (24-h MovBeh) paradigm, encompassing physical activity (PA), sedentary behaviour (SB) and sleep patterns, is recognised as a holistic approach to adolescent health. It emphasises promoting PA, reducing SB and ensuring sufficient sleep, especially in school environments. Understanding the links between lifestyle factors and health outcomes is crucial for clinical and public health, informing interventions for lifestyle changes among adolescents. This study aims to assess adherence to 24-h MovBeh among Lithuanian adolescents, examining the patterns, inter-relationships and impacts on socio-demographic status, 24-h MovBeh, health-related fitness, blood pressure, body composition, dietary patterns, health-related quality of life, mental health, physical and exercise motivation, other lifestyles and health indicators, and academic performance. The 24-h MovBeh study is a prospective cohort study beginning in 2025 with baseline data collected in schools. It will recruit 500 primary and secondary school adolescents (11-14 years old) from Klaipeda and Kaunas, Lithuania. The study will evaluate 11 main categories: Socio-demographic status, 24-h MovBeh, health-related fitness, blood pressure, body composition, dietary patterns, health-related quality of life, mental health, physical and exercise motivation, other lifestyles and health indicators, and academic performance. Statistical analysis will estimate adherence to 24-h MovBeh and its inter-relationships with individual and environmental factors and health outcomes. The 24-h MovBeh study will be a crucial step towards establishing a monitoring system for health and lifestyle outcomes, benefiting researchers, policymakers, adolescents, and parents, while laying the groundwork for future intervention studies.