A Web-Based Physical Activity Promotion Intervention for Inactive Parent-Child Dyads: Protocol for a Randomized Controlled Trial

Background Low levels of physical activity are associated with numerous adverse health outcomes, yet sedentary lifestyles are common among both children and adults. Physical activity levels tend to decline steeply among children aged between 8 and 12 years, even though children’s behavioral patterns are largely governed by familial structures. Similarly, parents’ activity levels have been generally reported as lower than those of nonparents of comparable age. For this reason, family-based physical activity promotion interventions are a potentially valuable and relatively underresearched method for mitigating physical activity declines as children develop into adolescents and for increasing physical activity in parents. Objective This study aims to assess the efficacy, feasibility, and acceptability of a novel theory-based web-based physical activity promotion intervention among parent-child dyads in Finland who do not meet physical activity recommendations at baseline. Methods Participants (target N=254) will be recruited from the general population using a panel company and advertisements on social media and randomly assigned to either an immediate intervention group or a waitlist control group. The intervention consists of 4 web-based group workshops over the course of 10 weeks, web-based tasks and resources, and a social support chat group. Data on physical activity behavior and constructs from the integrated behavior change model will be collected through self-report surveys assessing physical activity, autonomy support, autonomous motivation, attitude, subjective norm, perceived behavioral control, intention, self-monitoring, habit, and accelerometer measurements at baseline, post intervention, and 3 months post intervention. Exit interviews with participants will assess the feasibility and acceptability of the intervention procedures. Results This study will reveal whether the intervention changes leisure-time physical activity among intervention participants relative to the control group and will examine the intervention’s effects on important theoretical predictors of physical activity. It will also yield data that can be used to refine intervention materials and inform further implementation. Trial recruitment commenced in September 2023, and data collection should be completed by December 2024. Conclusions The planned intervention has potential implications for both theory and practice. Practically, the use of an entirely web-based intervention may have scalable future uses for improving physical activity in 2 key populations, while also potentially informing on the value of dyadic, family-based strategies for encouraging an active lifestyle as an alternative to strategies that target either parents or children independently. Further, by assessing change in psychological constructs alongside potential change in behavior, the intervention also allows for important tests of theory regarding which constructs are most linked to favorable behavior change outcomes. Trial Registration ClinicalTrials.gov NCT06070038; https://clinicaltrials.gov/study/NCT06070038 International Registered Report Identifier (IRRID) DERR1-10.2196/55960


Scientific quality, novelty and innovativeness of research
Significance of project; objectives and hypotheses; ambitiousness and state of the art of objectives (possible novel concepts and approaches or development across disciplines); scientific impact of research; potential for breakthroughs or exceptionally significant outcomes; etc.This project will develop and evaluate a theory-based intervention to promote sustained physical activity participation among sedentary parents and their children.It is a well written proposal.It is based on state-of-theart science, e.g.regarding use of theory in intervention development.Objectives, research questions and hypotheses are very clear and sound as well.The topic of increasing physical activity of sedentary parents and children is of high importance.However, the study as such is not really innovative or novel.These kind of theory-driven studies have been performed before.Still, if successful, the study outcome will have major societal (Public Health) impact, as the results must be translated into practice guidelines.The project will certainly have scientific impact.Methods are very well described.It is clear what will be done, and everything make sense.It is a lot of work, but it absolutely appears feasible.Measurements are well chosen and the rationale for choosing them are discussed.Good discussion on sample and power calculation.Smart to use the panel company to recruit.Scientifically this is state-of-the-art.Still, the proposal is not totally convincing that an intervention consisting of 8 intervention 'steps/modules' will lead to sustained physical activity behaviour change (i.e.beyond 12 months after baseline).Will the proposed relatively minimal intervention of short duration be able to counteract in a sustained way the upward behavioural pressures that are put on a child by the 'toxic environment' we live in?Also, it was somewhat unclear what the inclusion criteria is regarding level of physical activity.How sedentary must the parent and child(ren) be, and is it both that has to be sedentary?The track record of this applicant is outstanding.This project builds very well on previous work from his group.Research group is very well selected.Together they are very capable to conduct this research.

Significance of research collaboration and researcher mobility
Significance of national and/or international research collaboration (i.e.collaborators engaged in the project with their own funding) including complementary expertise and research environment of collaborators in terms of project implementation; significance of planned mobility for implementation of research plan and researcher training; etc.
Several well selected strong international collaborators with added (as well as overlapping) expertise to the project.Some mobility visits are included.Provide further comments if responsible science aspects above (3.1.1 -3.1.4)have not been properly considered.

3.2.2
Additional comments on societal effects and impact You are also encouraged to comment on the societal effects and impact, including principles of sustainable development.

Justifications and comments
Please justify the selections above by briefly describing the main strengths and weaknesses of the application.

Strengths:
The proposal is from a technical perspective written in a state-of-the-art manner. q The project is well planned. q The topic is important. q The research group is strong with strong collaborations.
q Weaknesses: It lacked a bit of innovativeness.
q It was somewhat unclear with the inclusion criteria. q (bearing in mind extent to which the proposed research may include high risks); materials, research data and methods; human resources and management of research tasks; research environment including research infrastructures; identified potential scientific or methodological problem areas and mitigation plan; etc.

2
Competence of applicant(s), quality of research collaboration 2.1 Competence of applicant(s) and complementary expertise of applicant's research team (project personnel) Merits and scientific expertise of applicant in terms of project implementation; complementary expertise of applicant's research team (i.e.project personnel directly working/funded for the project); competence of applicant(s) in terms of supervising PhD candidates or postdoctoral researchers; support for researcher training within project; etc.
of equality and non-discrimination within project or in society at large Yes

4
Overall assessment and rating 4.1 Main strengths and weaknesses of project Please select major strengths and weaknesses of the application.Give justifications for the selection in sub-item 4.2.4.1.1Main strengths (select all relevant aspects): ☑ scientific quality ☐ innovativeness and novelty value ☑ impact within scientific community ☑ feasibility of research plan ☐ significance and added value of consortium (if applicable) ☑ competence of applicant/s in terms of project implementation ☑ complementary expertise of research team (in terms of project implementation) ☑ significance of collaborative networks in terms of project implementation ☑ researcher training including researcher mobility 4.1.2Main weaknesses (select all relevant aspects): ☐ scientific quality ☐ innovativeness and novelty value ☐ impact within scientific community ☐ feasibility of research plan ☐ significance and added value of consortium (if applicable) ☐ competence of applicant/s in terms of project implementation ☐ complementary expertise of research team (in terms of project implementation) ☐ significance of collaborative networks in terms of project implementation ☐ researcher training including researcher mobility 4.2