A cluster randomized controlled trial of a positive physical activity intervention.

Objective: Due to global urbanization, technological advancements, and increasing convenience in daily activities, reduced energy expenditure in all aspects of life has become a major public health concern. A positive physical activity (PPA) intervention was developed to promote physical activity and fitness among Hong Kong families. PPA utilizes positive affective attitudes to circumvent barriers to health behavior change by helping families associate feelings of enjoyment with physical activity. Zero-Time Exercise (ZTEx) was introduced and promoted as a foot-in-the-door approach. Method: Using a community-based collaborative approach, the research team worked with social service organizations, a government department, and schools to implement a cluster randomized controlled crossover trial at a citywide scale. A total of 1,983 eligible participants from 1,467 families were recruited from all 18 districts in Hong Kong. Data were collected using structured questionnaires and physical fitness assessments at preintervention and 1-month and 3-month follow-up. Results: PPA was effective in increasing ZTEx and ZTEx with family members at 1-month and 3-month follow-up and in improving balance and endurance at 3-month follow-up. Semistructured focus groups provided further support for the intervention effectiveness and added in-depth insights into the participants' motivational, interpersonal, and affective experiences. Conclusion: The results not only shed light on the intervention's effectiveness for physical activity and fitness but also demonstrated that the community-based collaborative approach was successful in engaging relevant stakeholders in an active and fruitful partnership with effective capacity building for program development.