Physical Activity (PA) positively impacts a broad range of markers for health (King et al., 2019) and reduces the risk of mortality (Ekelund et al., 2026). The World Health Organisation (WHO) outline that almost 500 million people will develop noncommunicable diseases attributable to physical inactivity between 2020 and 2030 (WHO, 2022), with a global cost of $47·6 billion annually if urgent action is not taken by governments (Santos et al., 2023). Only 29% of European children and adolescents are currently sufficiently active (Steene-Johannessen et al., 2020), with 27.5% of the worlds adults not achieving global recommendations (Guthold et al., 2020). It is now well established that European and Global society are largely physically inactive (Strain et al. 2024).
Physical Activity levels track from youth into adulthood (Hayes et al., 2019) and current trends suggest youth participation is not increasing (Guthold et al., 2018). This highlights a substantial public health issue, as early incidence of risk factors for chronic disease associated with physical activity behaviours (PABs) are on the rise (Lascar et al., 2018, Song et al., 2019). The Lancet commission and the WHO Global Accelerated Action for the Health of Adolescents have highlighted a triple benefit to investment in youth health – immediate, lifelong and intergenerational, referencing PA as a research priority (Patton et al., 2016, WHO, 2017).
Expert consensus indicates that “a whole systems approach, with radical change at social, environmental, and systems levels, through multidisciplinary and cross-sectorial collaboration” is required (van Sluijs et al., 2021). The DEterminants of DIet and Physical Activity Knowledge Hub (DEDIPAC-KH) consortium identified major gaps in the depth, breadth and quality of data on multi-level and multidisciplinary determinants of PABs, limiting effective policy and intervention development (Brug et al., 2017; De Craemer et al., 2018).INDEEP addresses this by advancing our understanding of the determinants to inform targeted and effective interventions, policies and infrastructures (Pratt et al., 2023).
There is an immediate need to train a new generation of multidisciplinary Doctoral Candidates (DCs) who can examine best existing evidence on PAB determinants and map this knowledge onto the design of interventions and policy, helping to reshape the PAB system favourably (Rutter et al., 2017) and improve effectiveness and return on investment (Ding et al., 2019, Conner and Norman, 2017).
Consequently, the research objectives of INDEEP are:
1. Develop an innovative methodology to generate new knowledge on the biological, intrapersonal, interpersonal, social, environmental, and policy determinants of PABs by exploiting European large-scale cohort studies and a concept proof in a sample of European youths (12-14 years) from five European countries.
2. Identify vulnerable groups most likely to benefit from PAB interventions and policies.
3. Apply a comprehensive determinants system to identify key determinants to target when designing PAB interventions
4. Develop a co-creative Toolbox for practitioners grounded in behaviour change theory.
These objectives will deliver a harmonised multi-site dataset of PABs and associated determinants, supporting evidence-informed interventions and responding to gaps identified by WHO (2019) and the research community (Bauman et al., 2012; van Sluijs et al., 2021).
The methodologies developed will inform an INDEEP Toolbox to support the translation of research into real-world practice. Interdisciplinary training for Doctoral Candidates, combined with strong international expertise and collaboration, will help ensure the efficacy and impact of INDEEP outputs, and advance the state of the art.
