Document Type



Objectives - To describe the objectively-measured physical activity (PA) characteristics of a diverse sample of 6th grade girls to examine influences on PA, and to report compliance with PA guidelines.

Design - Cross-sectional study.

Setting - Six locations across the United States.

Participants - 1578 6th grade girls. Actigraph accelerometers were worn for 7 days, and data for 6 days were included in the analyses.

Main exposure - Race/ethnicity, free-or-reduced price lunch (FRPL), and geographic region.

Main outcome measure - Six operational definitions of adequate activity (60 min or 30 min of daily MVPA at or above 4.6, 3.8 or 3.0 METS (metabolic equivalents)) were applied to examine whether girls met physical activity guidelines.

Results - Average time spent in sedentary, light, moderate, and vigorous activities was 460, 342, 18, and 6 min/day, respectively. White girls were more active than girls in other race/ethnic groups, and girls who did not receive FRPL were more active than girls who did. Girls in western states were most active. Percentages of girls in compliance with the 6 thresholds for adequate activity varied widely, and ranged from 0.6% to 99.8%.

Conclusions - When physical activity is measured objectively and a 4.6 MET cupoint for MVPA is applied, most 6th grade girls fall below guidelines for adequate physical activity. One notable finding was the impact of different accelerometer scoring protocols on estimates of compliance. Conceptual and empirical work is needed to define appropriate physical activity for youth using objective physical activity measures.

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