From heart to motion : advancing physical activity measurement in children

Physical activity (PA) is a fundamental determinant of health across the lifespan, recognized as a key factor in the prevention and treatment of disease. In childhood and adolescence, regular PA supports healthy growth, cardiorespiratory fitness, psychological well-being, and the development of lifelong health behaviours. The overarching aim of this dissertation is to address this challenge by developing, validating, and applying improved methods for measuring PA using accelerometry in children and adolescents, with a particular focus on those with congenital heart disease.