Correlates of physical activity in fifth-grade students in Ho Chi Minh City, Vietnam.

Studies investigating correlates of physical activity (PA) using objective PA measurements among primary school-aged children are limited in Asia, particularly Vietnam. This study examined psychosocial and environmental factors associated with PA among fifth-grade students in eight primary schools in Ho Chi Minh city, Vietnam. Bivariate analyses showed that for every month increase in students' age, an increase of 66 steps/day (p<0.05) was found; boys had 1442 more steps/day than girls (p<0.001); and students from lower income households had 1169 steps/day less than those from higher income households (p<0.01). For every unit increase in self-efficacy, perceived social influences, intention to be physically active, and parental support for PA, an increase of 220, 200, 522, and 117 steps/day (p<0.01) was found respectively. In multivariable analysis, only intention and parental support for PA remained significant (p<0.01). About 21% of variation in daily steps was explained by demographic characteristics and an additional 13% by psychosocial influences. In conclusion, intention to be physically active and parental support are important factors and should be considered when designing PA interventions in school/community-based settings.

Psychometric properties of questionnaires to measure social ecological influences in Vietnamese children.

Physical activity data in primary school-aged children are limited in Vietnam. Although tools to measure social ecological influences on physical activity are validated in English, they are not available in Vietnamese. Due to cultural and contextual differences, their psychometric properties need to be tested. Five scales were translated into Vietnamese and evaluated for internal consistency and test re-test reliability, including self-efficacy, perceived social influences, and beliefs self-administered by students, and parental support for physical activity and parental perceived safety of the neighbourhood, self-administered by parents. Compared to the original scales, two items from the parental perceived neighbourhood safety were removed due to the cultural context. Another item of the self-efficacy scale was also removed as it correlated poorly with the other items in the scale at both administrations. The adjusted scales were found to be reliable and appropriate for use among students and parents to measure social ecological influences on physical activity in the Vietnamese context.