The purpose of this study was to compare physical activity in fifth-grade primary school children using a questionnaire and an accelerometer. A total of 34 participants (15 boys and 19 girls) aged 10–11 years participated in this study. A questionnaire and an accelerometer were used to assess and exercise time and moderate-to-vigorous physical activity (MVPA), respectively. Participants were classified into two groups, i.e., meeting ≥60 min/day MVPA group and non-meeting MVPA ≥60 min/day MVPA group, based on the results of questionnaire assessment and MVPA was compared. Except for all children and girls on weekdays, the exercise time assessed by the questionnaire was significantly different from the MVPA measured by the accelerometer. There were significant differences in MVPA between the meeting ≥60 min/day MVPA group and non-meeting MVPA ≥60 min/day MVPA group on weekends in all children and on weekdays and all-days in boys. Agreement between physical activity guideline meeting and non-meeting, as assessed by questionnaire and accelerometer, showed significant agreement only for all children in weekends (φ=0.35, p<0.05). In conclusion, our study suggested that it is not appropriate to use the exercise time assessed by the questionnaire and MVPA assessed by the accelerometer as equivalent measures of activity for fifth-grade students.
