Socio-ecological correlates of physical activity in a nationally representative sample of adolescents across Ireland and Northern Ireland.

Physical activity (PA) is associated with a range of health benefits for adolescents. Few adolescents meet one hour daily of moderate-to-vigorous physical activity (MVPA). The World Health Organisation (WHO) now recommends an 'on average' accumulation. In light of these updates, comparing correlates associated with meeting versus not meeting the PA guidelines provides limited understanding of adolescent behavioural choices. The aim of this study was to fractionate PA behaviour and investigate influential socio-ecological correlates across a diverse range of PA categories. A nationally representative sample (N = 6,563; age = 13.5 ± 1.9 years; male = 46.2%) completed a researcher supervised self-report survey. Empirically established instruments assessing the socio-ecological correlates of PA were included. Levels of MPVA were categorised into (60mins.MVPA.daily), (60mins.MVPA.5-6 days), (60mins.MVPA.3-4 days) or (60mins.MVPA.0-2 days). Descriptive statistics, chi-square analyses and multivariate blockwise binary logistic regression models were run separately for each PA category. Few were daily active (12.7%), 33.6% active, 36.5% somewhat active and 17.2% were inactive. Results showed that correlates differed in terms of direction and strength, depending on individual activity status. Increasing age was positively associated with being somewhat active, but not with being active or daily active. Attending an 'all-girls school' was negatively associated with daily active. High interpersonal support from family, friends or teachers was negatively associated with inactive or somewhat active, reducing the likelihood of adolescents remaining in these unhealthy PA categories. This novel information is useful for exploring previously established inconsistent relationships with PA. More sensitive categorisation and intervention tailoring to diverse PA categories is required.