Objective:The present study examined physical activity(PA)levels and differences in PA by gender and grades during school recess periods. Method:PA levels of two hundred and thirty children(55% boys, 42%younger)from two elementary schools in Japan were measured with accelerometry for seven consecutive days. Time spent in sedentary, light PA, moderate PA, vigorous PA during break(25 minutes)and lunch recess(15 minutes), and total recess(40 minutes)was determined. Two-way analysis of variance was used to examine differences in PA variables by gender and grades. Results:Data of one hundred and eighty four children(52% boys, 56% younger)was available. Time spent in sedentary, light PA, moderate PA, and vigorous PA was 8.5±4.9, 12.9±3.8, 1.6±1.2, and 2.9±2.8 minutes during break, and 3.5±2.5, 9.5±2.2, 1.4±0.9, and 1.6±1.4 minutes during lunch recess, respectively. There were no significant interactions between gender and grades. Significant main effects of PA variables were found for gender and grades. Boys had fewer sedentary time(p=0.017)and higher vigorous PA time(p<0.001)than girls during total recess. Younger engaged in more sedentary(p=0.045)and less light(p=0.023)and moderate PA(p=0.006)than older at break. On the other hand, at lunch recess, younger had significantly longer light(p=0.015)and vigorous PA(p<0.001)and shorter sedentary time(p<0.001)than older. Conclusion:Overall, boys were less sedentary and engaged in PA at higher intensity levels than girls during school recess. Different pattern in PA was shown between break and lunch recess by grades.
