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Nutrition and Food Sciences



Increasing children’s physical activity (PA) at school is critical to obesity prevention and health promotion. Implementing novel, low-cost PA programs offers potential to contribute to children’s in-school PA, particularly in resource-constrained schools. This evaluation describes implementation fidelity, reach, and dose of two PA programs in the Fueling Learning through Exercise (FLEX) Study.


Thirteen diverse, low-income Massachusetts elementary schools were recruited and randomized to the 100 Mile Club walking/running program (n = 7) or CHALK/Just Move classroom activity break PA program (n = 6). Intervention programs were delivered across two school years. Surveys with program champions/teachers and children, in-session measurement of children’s PA by accelerometry (Actigraph GT3X) in a subset of schools, and key informant interviews were used to collect information on implementation, including fidelity, dose, reach, and sustainability, and to calculate an implementation score.


Six CHALK/Just Move schools implemented the program in both years. Two schools randomized to 100 Mile Club did not implement at all, and only three schools implemented both years. Implementing schools had similar implementation scores (range = 0–3; 100 Mile Club = 2.0 vs. CHALK/Just Move = 1.9) but fidelity to core and enhanced elements differed between programs. In 100 Mile Club schools, dose of program delivered was greater than in CHALK/Just Move schools (34.9 vs. 19.7 min per week). Dose of PA received per session was also greater in 100 Mile Club schools (n = 55, 2 schools) compared with CHALK/Just Move schools (n = 160, 2 schools) (13.6 min vs. 2.7 min per session). A slightly higher proportion of eligible children participated in CHALK/Just Move compared to 100 Mile Club (54.0% vs. 31.2%). Both programs were well received by champions/teachers and students.


Program implementation varied across programs and schools, and erosion in delivery was seen over the two years. However, among implementing schools, additional PA was delivered and received, and the programs were generally well-received. Although school resource issues remain barriers to implemention, this evaluation demonstrates that low-cost programs may enhance PA opportunities. Future research should evaluate how multiple programs can be implemented to increase children’s PA at school.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.