Children's intervention participation is associated with more positive beliefs towards active school transportation among parents.

Insufficient physical activity among children is a critical issue and health promoting initiatives are required to reverse this trend. In response to the current situation, a school-based intervention aiming to increase physical activity with the aid of active school transportation (AST) was implemented in one municipality in northern Sweden. By adopting the framework of the Theory of Planned Behavior, we aimed to analyse beliefs among parents whose children were or were not involved in the AST intervention. All municipality schools were included. There were 1024 responses from parents, comprising 610 who responded either 'yes' or 'no' to participating in the intervention. An adjusted linear regression analysis showed that children's intervention participation was significantly associated with more positive beliefs towards AST among parents. These results indicates that it is possible to influence beliefs that are important in the parental decision-making process by the use of an AST intervention. Therefore, to make children's active transport to school the more favorable choice for parents, it seems to be worthwhile to not only give children the opportunity to participate but also to involve parents and address their beliefs when designing interventions.