Fig. 1From: Temporal trends in physical activity levels across more than a decade – a national physical activity surveillance system among Norwegian children and adolescentsNumber of participants that were invited, participated, provided valid PA data and were included in the main analyses of the present study by PANCS cohort and age group. *1119 of the invited had previously participated in 2005 when aged 9, of which 731 chose to participate when aged 15 years in 2011Back to article page