Assessment of Physical Activity among Hong Kong Primary Schoolchildren by Questionnaire

Abstract

PURPOSE: To evaluate the test-retest reliability and validity of the 7-day recall physical activity questionnaire by ActiGraph monitor among primary schoolchildren in Hong Kong. METHODS: Nineteen boys (mean ± SE: age=10.8 ± 0.2 yr, BMI=18.8 ± 0.8 kg-2) and 50 girls (mean ± SE: age=10.3 ± 0.1 yr, BMI=17.2 ± 0.5 kg-2) completed a 7-day recall physical activity questionnaire on two occasions, one week apart. The questionnaire was modified from The Children's Leisure Activities Study Survey (CLASS) (Telford et al., 2004). All of the children wore an ActiGraph monitor during waking hours for seven consecutive days. Activity counts were recorded into the time spent in moderate and vigorous physical activity, using the age-specific cut-off points developed by Freedson and co-workers (1998). Intraclass correlations coefficient (ICCs) were analyzed to determine the consistency of the questionnaire. Validity of the questionnaire was determined by performing Pearson coefficient correlations, and mean difference and 95% CI between questionnaire and ActiGraph data in time spent on activity. RESULTS: Repeatability of the self-reported duration in moderate activity was higher at weekends (ICC = 0.64, P<0.05) compared to that on weekdays (ICC = 0.36, P<0.05). Desirable consistency in reported vigorous activities, however, was only shown during weekdays (ICC = 0.70, P<0.05). Self-reported duration in overall time on physical activity showed moderate stability (ICC = 0.60, P<0.05). No difference were found in the total time spent in moderate and vigorous physical activity per day (mean difference = −4.7min, 95% CI: −13.7-4.3min, P>0.05), and self-reported time spent in total physical activity was moderately correlated to that assessed by accelerometer (r = 0.44, P<0.05). However, children overestimated the duration in vigorous activity (mean difference = 5.9min, 95% CI = 2.8–9.0min, P<0.05). CONCLUSIONS: The findings suggested that the 7-day recall physical activity questionnaire has moderate reliability and validity in assessing the overall physical activity among Hong Kong primary schoolchildren. However, children overestimated their levels of vigorous activity by self-report questionnaire.