Background: Inadequate opportunities for physical activity at school and overall low levels of activity contribute to the high prevalence of overweight and obesity in American-Indian children.
Methods: A school-based physical activity intervention was implemented which emphasized increasing the frequency and quality of physical education (PE) classes and activity breaks. Changes in physical activity were assessed using the TriTrac-R3D accelerometer in a subsample of 580 of the students (34%) randomly selected from the Pathways study cohort. Baseline measures were completed with children in second grade. Follow-up measurements were obtained in the spring of the fifth grade.
Results: Intervention schools were more active (+6.3 to +27.2%) than control schools at three of the four sites, although the overall difference between intervention and control schools (approximately 10%) was not significant (P>0.05). Boys were more active than girls by 17 to 21% (P < or =.01) at both baseline and follow-up.
Conclusions: Despite the trend for greater physical activity at three of four study sites, and an overall difference of approximately 10% between intervention and control schools, high variability in accelerometer AVM and the opportunity to measure physical activity on only 1 day resulted in a the failure to detect the difference as significant.