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Purpose - To determine the annual rate at which physical activity changes in girls during middle school using both objective and self-report measures of physical activity.

Methods - Participants were 6th and 8th grade girls from the control schools in the Trial of Activity for Adolescent Girls (TAAG). Random cross-sectional samples initially were drawn from 6th grade girls (n=786) and two years later from 8th grade girls (n=1545). A cohort of 501 girls was in both the 6th and 8th grade samples. The girls wore an accelerometer for six days and completed the 3-Day Physical Activity Recall (3DPAR). Data were summarized using 3.0-4.6- and 6.5-MET cutpoints for accelerometry and self-reported physical activity. Analyses were performed using repeated measures ANOVA in PROC MIXED.

Results - More than 40% of the girls were White, approximately 20% were African-American, and 20% were Hispanic. The annual percent decrease in physical activity in the cross-sectional sample was approximately 4% (-1.76 min MVPA/day), using accelerometer data. The percent decrease in physical activity based on self-report data was higher, 6-13%, depending on the physical activity variable. Declines tended to be larger in African-American girls, but the ethnic differences were not statistically significant.

Conclusions - Based on comparisons of cross-sectional samples of 6th and 8th grade girls, objectively-measured physical activity declined at a rate of 4% per year.


Pate, R. R., Stevens, J., Webber, L. S., Dowda, M., Murray, D. M., Young, D. R., & Going, S. (2009). Age-related change in physical activity in adolescent girls. Journal of Adolescent Health, 44(3), 275-282.

DOI: 10.1016/j.jadohealth. 2008.07.003

NOTICE: This is the author's version of a work that was accepted for publication in Journal of Adolescent Health. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Adolescent Health, Vol. #44, Issue #3, (2009), DOI: 10.1016/j.jadohealth.2008.07.003

© Journal of Adolescent Health, 2009, Elsevier

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