Promoting active outdoor play and healthy dietary behaviours through the co-creation of supporting physical and social environments for and with primary school-aged children living in underserved neighbourhoods in Europe: the protocol of the B-Challenged project.

An alarmingly low number of children meet public health guidelines for physical activity and dietary behaviours, increasing their risk of lifestyle-related diseases.

• This concern motivated the development of the B-Challenged project protocol.
• The project targets children aged 6-12 years in underserved neighbourhoods across five European countries.
• The focus is on both active outdoor play and healthy dietary behaviours before, during, or after outdoor play.

The B-Challenged project employs child-centred Participatory Action Research (PAR) combined with systems dynamics methods across five European countries.

• Each country engages 15-20 child co-researchers aged 9-12 years.
• Each country also engages 15-20 adult actors, such as youth workers and local policy makers.
• The project is conducted in underserved neighbourhoods in Europe.
• The approach combines PAR with systems dynamics methods to map and address drivers of children's behaviours.

The project is structured in two phases: a mapping phase and an implementation/co-creation phase.

• Phase one maps the main drivers of children's active outdoor play and related dietary behaviours by analysing existing cohort data and conducting child-centred PAR.
• Phase two involves co-creating and implementing systemic actions targeting local physical and social environments.
• Actions in phase two are co-created by child co-researchers and adult actors together.
• Ethics approval for the mapping phase was already obtained at the time of publication; approval for implementation and evaluation was pending from five local research institutions.

A mixed-methods design will be used to evaluate three distinct outcomes of the B-Challenged project.

• Evaluation outcome 1: whether actions positively contributed to systems change and 6- to 12-year-olds' outdoor play and related dietary behaviours, with 140 children per country.
• Evaluation outcome 2: the process of conducting multi-actor, child-centred PAR and implementing co-created actions.
• Evaluation outcome 3: whether child-centred PAR positively contributed to child co-researchers' feelings of empowerment.
• The total evaluation sample involves 140 children per country across five countries.

The project incorporates child-friendly methods, materials, and language throughout, and explicitly addresses ethical challenges.

• Participating children, one of their parents/caregivers, and adult actors provided informed consent before participating.
• Child-friendly methods and materials are applied throughout the project.
• Ethical challenges and potential solutions are discussed as part of the protocol.
• The project is registered under NCT07136376.

Project results will be disseminated both locally and internationally through multiple channels targeting diverse audiences.

• Dissemination targets include the scientific community, health and policy-making professionals, children, and other citizens.
• Both local and international dissemination channels and activities are planned.
• The dissemination strategy reflects the multi-stakeholder nature of the project.