Behavioural Epidemiology of Physical Activity

Physical activity is important for young people’s current and future health. However, it appears that many young people are not active enough to enjoy these health benefits. We also know that children do less physical activity when they become older, particularly during teenage years. Identifying ways to maintain and promote young people’s levels of physical activity is therefore important for public health.

Physical activity behaviour is complex, not just consisting of sports activities but including behaviours such as walking the dog, cycling to school, playing in the playground and physical education lessons. How active young people are is influenced by many factors, such as their preference for physical activity, the provision of footpaths in the neighbourhood, weather and how much their parents support them in being physically active. How these factors work together in promoting physical activity and how to use this knowledge to promote increases in physical activity is still largely unknown.

The Behavioural Epidemiology of Physical Activity Group therefore aims to improve the long-term health of young people by:
- developing and evaluating interventions to increase physical activity in young people
- increasing our understanding of where, when and how physical activity interventions in young people may be applied

Physical activity during childhood is important for both contemporary and future health. Evidence suggests that young people’s levels of physical activity are insufficient for health. More importantly, physical activity on average declines with age. Identifying ways to maintain and, where applicable, promote physical activity in young people is therefore a key public health issue.

Physical activity is a complex behaviour, influenced by a combination of factors from multiple ecological levels, including individual, socio-cultural, policy and environmental-level factors. The relative importance of these factors and how they interact is still largely unknown. Moreover, our current understanding is largely based on cross-sectional evidence, limiting our ability to draw conclusions about causality and inform intervention development.

The two main aims of the Behavioural Epidemiology of Physical Activity Group are to:
- develop and evaluate interventions to promote physical activity in young people
- use observational research to further understand where, when and how physical activity interventions in young people may be targeted

Intervention development and evaluation are a core part of the programme. Using a structured and iterative approach, we undertake explanatory trials to understand the feasibility and effectiveness of specific intervention strategies based on our previous observations. This approach allows for a greater understanding of the causal mechanisms behind behaviour change, and the potential effectiveness of specific components of future, more complex, interventions to be evaluated later. An example is the development and evaluation of a physical activity promotion intervention targeted at families, instead of the child alone. Here, we will use the intervention mapping approach to guide intervention development, and design a high quality evaluation including objective measurement of family-based physical activity.

To inform future intervention development, we will continue to increase our understanding of physical activity behaviour, its influences and consequences throughout the different stages of childhood, with a predominant focus on prospective data. An example dataset we will use for this is the International Children’s Activity Database (ICAD). ICAD is an open-access dataset which aims to overcome comparability issues of single studies and currently holds data for over 30 000 children world-wide. We will both utilize the existing ICAD dataset as well as strengthen it by adding additional data to increase its utility for longitudinal analyses and the identification of influences on behaviour.

In summary, this programme aims to develop and evaluate interventions to change young people’s activity behaviour through a thorough understanding of the patterns, consequences, correlates and determinants of the behaviour of interest. The work will lead to the evaluation of comprehensive physical activity promotion interventions at different stages of childhood with the aim of improving the long-term health of young people.