Children's Cooperation Denmark (Child-COOP): Promoting Healthy Physical Activity Behaviour in Children Aged 6-12 Years: a 3-year System Dynamics Trial

The Child-COOP trial was developed according to the United Kingdom Medical Research Council's framework for developing and evaluating complex interventions. Two feasibility studies were initiated in 2021 and still running - and Child-COOP was subsequently adapted and adjusted.

INTRODUCTION Lack of physical activity (PA) and sedentary lifestyle in Danish children is a major challenge. New strategies are needed to combat this development. Early awareness and promotion of healthy PA behaviour is important, as PA behaviour in childhood often is manifested across adolescence and into adulthood. Social inequity in health is also mirrored in PA behaviour among children. Children in families with few resources are known to be less physically active compared to peers in more affluent families. One way to promote healthy PA behaviour in children, which also considers inequity challenges, is to develop more health-enhancing active leisure communities. Unfortunately, dropout from active leisure communities is common in the transition from childhood to adolescence. These high dropout rates call for identification of initiatives that encourage children to engage in active leisure communities throughout childhood and youth. However, both sedentary behaviour and moderate-to-vigorous PA have been found to be independent predictors for health status, and they are not mutually related. Hence, focussing solely on reaching the recommended levels of daily PA is not sufficient. Instead, a comprehensive strategy is warranted to ensure that more time is spent on light, moderate and vigorous PA and less time on sedentary activity. Promoting (initiating and sustaining) a healthy PA behaviour is not an easy task because PA behaviour is shaped by a complex interplay between a wide range of factors at individual, family, community and society levels. Interventions building on a participatory system dynamics approach has been suggested as a feasible way to address such complex problems as they combine the current evidence base on prevention, best practice and local wisdom to achieve new knowledge and create solutions. A participatory system dynamics approach implies that a variety of engagement and solutions at different system levels may occur at both the interpersonal and organisational levels. This strategy has already proven successful in several international childhood obesity prevention interventions. The participatory system dynamics approach remains to be tested in a large-scale Danish context. During the past year, our research group has tested the participatory system dynamics approach in different settings in Denmark. We propose to conduct a participatory system dynamics trial across ten communities in five municipalities to create local solutions to promote healthy PA behaviour in Danish schoolchildren through Child-COOP.

AIM

The overall aim is to evaluate a participatory system dynamics approach to promote (increase and sustain) healthy PA behaviour in 6- to 12-year-old schoolchildren in local communities in Denmark through the following sub-aims:

• Measuring the effectiveness on the children's PA behaviour by assessing changes in time spent sedentary and time spent at light, moderate and vigorous intensity at three-year follow-up
• Estimating changes at system level such as assessing changes in community systems, community networks structure, policy and practice at three-year follow-up
• Identifying health-economic implications by assessing both a cost consequence analysis and an explorative analysis of the derived effects at three-year follow-up
• Conducting a process evaluation to map a final systems program theory on "what works for whom under what circumstances" to be used as a framework in future recommendations and up-scaling.