Abstract
Introduction: High rates of physical inactivity that rapidly deteriorate during adolescence are a global public health crisis. In Aotearoa New Zealand (NZ) this coincides with relatively high levels of negative wellbeing outcomes and requires immediate action. Improving physical activity (PA) participation levels and the quality of PA opportunities for adolescents in NZ may enhance holistic wellbeing outcomes. Understanding the PA and wellbeing context experienced by adolescents is critical for developing PA promotion initiatives that encourage lifelong participation and optimal wellbeing outcomes. I investigated potential population-level PA interventions and their influence on the current and future PA and wellbeing of NZ adolescents.
Methods: I reviewed and critiqued the Sport NZ Outcomes Framework focusing on physical activity, wellbeing, and equity. This provided an underpinning theoretical framework for my thesis. I then conducted a literature review that focussed on adolescents and what determined whether they remained physically active into early adulthood. This informed my choice of exposure and outcome variables that I used in subsequent quantitative analysis of existing data. By analysing data from the Active NZ Young People Survey, I quantified the determinants of future PA participation for a nationally representative sample of NZ adolescents aged 12-17 years (n=6906). These results provided baseline data for two simulation models I subsequently developed to test the potential impact of hypothesised PA promotion interventions targeted at adolescents in NZ. The first model examined the potential impact of interventions within secondary school settings. The second model examined the potential impact of active transport interventions for adolescents.
Results: The Sport NZ Outcomes Framework outlined the connection between population-level PA participation and national wellbeing outcomes. I found that it could be improved by: acknowledging a more holistic range of wellbeing outcomes, making culture an overarching principle in the framework, and promoting local population autonomy in decision-making processes for PA and wellbeing promotion.
My literature review revealed several hypothesised adolescent determinants of sustained PA participation into adulthood. Of these determinants, five displayed a clear and positive association with future PA.
Descriptive analysis of Active NZ data for adolescents revealed differences between sociodemographic groups for the following determinants of future PA participation: weekly PA amount, PA types, PA settings, physical literacy, and social support. Lower scores were noted for adolescents who were older, Asian, gender diverse and living in low socio-economic neighbourhoods.
Our first modelling results revealed that all four simulated secondary school interventions benefitted the current PA determinants of future PA for NZ adolescents. The magnitude of change for each determinant varied substantially according to the specific intervention condition, which demonstrates the need for a nuanced approach to intervention depending on the school context.
Our second modelling results suggest that adolescent-focused active commuting to school interventions will likely have a wide range of short and long-term PA and wellbeing impacts for NZ adolescents. Compared to Western interventions, Māori-centered approaches to active transport may have additional impacts, but this requires further evaluation.
Conclusions: Population-level PA interventions tailored to adolescents and relevant to the surrounding context can positively influence current and future PA behaviours and wellbeing. Implications from our findings may help guide future approaches and policies within the local and national PA system and improve wellbeing frameworks and intervention development internationally. However, my findings were limited by the quality of existing data and gaps in the intervention literature. Therefore, future work should focus on collecting more comprehensive longitudinal PA and wellbeing data and evaluating effective real-life adolescent-focused interventions.