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HOP'N after-school project: an obesity prevention randomized controlled trial

David A Dzewaltowski1*, Richard R Rosenkranz12, Karly S Geller12, Karen J Coleman3, Gregory J Welk4, Tanis J Hastmann12 and George A Milliken5

Author Affiliations

1 Department of Kinesiology, Kansas State University, Manhattan, KS 66506, USA

2 Department of Human Nutrition, Kansas State University, Manhattan, KS 66506, USA

3 Research and Evaluation, Southern California Permanente Medical Group, Pasadena, CA 91101, USA

4 Department of Kinesiology, Iowa State University, Ames, IA 50011, USA

5 Department of Statistics, Kansas State University, Manhattan, KS 66506, USA

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International Journal of Behavioral Nutrition and Physical Activity 2010, 7:90  doi:10.1186/1479-5868-7-90

Published: 13 December 2010



This paper reports the primary outcomes of the Healthy Opportunities for Physical Activity and Nutrition (HOP'N) after-school project, which was an effectiveness trial designed to evaluate the prevention of childhood obesity through building the capacity of after-school staff to increase physical activity (PA) and fruit and vegetable (FV) opportunities.


We conducted a three-year, nested cross-sectional group randomized controlled effectiveness trial. After a baseline assessment year (2005-2006), schools and their after-school programs were randomized to the HOP'N after-school program (n = 4) or control (n = 3), and assessed for two subsequent years (intervention year 1, 2006-2007; intervention year 2, 2007-2008). Across the three years, 715 fourth grade students, and 246 third and fourth grade after-school program participants were included in the study. HOP'N included community government human service agency (Cooperative Extension) led community development efforts, a three-time yearly training of after-school staff, daily PA for 30 minutes following CATCH guidelines, a daily healthful snack, and a weekly nutrition and PA curriculum (HOP'N Club). Child outcomes included change in age- and gender-specific body mass index z-scores (BMIz) across the school year and PA during after-school time measured by accelerometers. The success of HOP'N in changing after-school program opportunities was evaluated by observations over the school year of after-school program physical activity sessions and snack FV offerings. Data were analyzed in 2009.


The intervention had no impact on changes in BMIz. Overweight/obese children attending HOP'N after-school programs performed 5.92 minutes more moderate-to-vigorous PA per day after intervention, which eliminated a baseline year deficit of 9.65 minutes per day (p < 0.05) compared to control site overweight/obese children. Active recreation program time at HOP'N sites was 23.40 minutes (intervention year 1, p = 0.01) and 14.20 minutes (intervention year 2, p = 0.10) greater than control sites. HOP'N sites and control sites did not differ in the number of FV offered as snacks.


The HOP'N program had a positive impact on overweight/obese children's PA and after-school active recreation time.

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