Comparative dynamicsof physical activity in children aged11–13

Introduction: Physical activity is essential forchildren’s health and quality of life. However, less than 20%of children worldwide meet the WHO’s physical activityrecommendations, and activity levels often decreaseduring weekends. In Bulgaria, students are generallyinactive during the school week and spend weekends insedentary screen-related behaviors. This study aims toassess the duration and type of physical activity amongBulgarian students aged 10 to 13, with a focus on differencesbetween weekdays and weekends. Methods: The studyinvolved 387 students (221 girls, 166 boys) from grades 5to 7. Physical activity was measured using Axivity AX3motion sensors worn continuously for 7 consecutive days.Data were excluded if wear time was less than 6 hoursper day. Parents also provided information regardingtheir children’s extracurricular activities. Results anddiscussion: Fifth-grade students exhibited slightly moresedentary behavior on weekends compared to weekdays,although the difference was not statistically significant.In contrast, sixth- and seventh-grade students showed amarked increase in sedentary time on weekends, especiallyboys, who spent up to 60.5 minutes more sitting. Highintensityphysical activity declined significantly across allgrades during weekends. Conclusion: As children age,their overall physical activity decreases—most noticeablyon weekends and among boys. To counter this trend, it isessential to implement school-based initiatives, promote active breaks, and launch educational campaigns targetingfamilies and communities.