Promoting physical activity and health in Hong Kong primary school children through a blended physical literacy intervention: protocol and baseline characteristics of the "Stand plus Move" randomized controlled trial

Background: Children predominantly remain sedentary in a traditional classroom. This study aimed to demonstrate the design and baseline characteristics of a three-armed intervention program that targeted enhancements in children's physical literacy (PL), physical activity (PA), sleep, and executive functions by constructing an active classroom environment in primary schools. The blended approach involved organized PA participation during recess combined with changes to the classroom environment in response to the emphasis on nurturing children's PL in Hong Kong. Methods: This blended "Stand + Move" intervention adopted a randomized controlled trial design to investigate its effectiveness in improving health-related aspects. Three groups were compared: (1) PA recess intervention, (2) blended (sit-stand desks and PA recess) experimental, and (3) control groups. In this 13-week intervention (from March to September 2019), 76 students (59.2% girls) were recruited and randomly assigned to the three groups. The primary outcomes were children's PL and PA. The secondary outcomes were children's sleep and executive functions. Results: Baseline data were evaluated. The mean age was 9.6 years [standard deviation = 0.61, range 9.0-12.0]. There were no significant differences between trial arms at baseline concerning any of the outcomes (all P = 0.06-0.89). Overall, 22.4% met the recommended PA guidelines, 36.8% met the sleep guidelines, and 10.5% met both guidelines. Three aspects of executive functions were evaluated: inhibition, executive control, and planning. Over half of the participants reported satisfaction with their perceived sleep quality. Conclusions: The designed intervention is regarded as an innovative strategy that incorporates sit-stand desks and PA breaks to reconstruct children's traditional classroom environment. The baseline results suggest that intervention was satisfactory in reducing students' sitting time and increasing their PA engagement. We demonstrated the benefits of this intervention on children's PL, various sleep patterns, and executive functions. As expected, the designed intervention changes made to the classroom improved children's health behaviors, as well as the support from stakeholders at schools and the children's families. Our results also provided the desired evidence for policy reforms in teaching and learning strategies.