Study protocol of a population-based cohort investigating Physical Activity, Sedentarism, lifestyles and Obesity in Spanish youth: the PASOS study

Introduction Physical activity (PA) is essential to healthy mental and physical development in early life. However, the prevalence of physical inactivity, which is considered a key modifiable driver of childhood obesity, has reached alarming levels among European youth. There is a need to update the data for Spain, in order to establish if current measures are effective or new approaches are needed. Methods and analysis We present the protocol for Physical Activity, Sedentarism, lifestyles and Obesity in Spanish youth (PASOS). This observational, nationally representative, multicentre study aims to determine the PA levels, sedentary behaviours and prevalence of physical inactivity (defined as