Evaluating Mailed Motivational, Individually Tailored Postcard Boosters for Promoting Girls' Postintervention Moderate-to-Vigorous Physical Activity.

backgroundWays to optimize boosters to assist girls to attain adequate moderate-to-vigorous physical activity following an intervention are unknown.

objectiveThis study's purpose was to (a) determine whether girls receiving mailed motivational, individually tailored postcard boosters following a 17-week physical activity intervention would have greater moderate-to-vigorous physical activity at 9-month follow-up as compared to girls not receiving them and those in a control group and (b) evaluate girls' perceptions of the booster intervention.

methodsSixth to seventh grade girls (n = 117) from two urban, Midwest schools with similar demographic characteristics participated in a 17-week physical activity intervention, and girls from a third school served as controls (n = 64). One (n = 54) of the two intervention schools was randomly assigned to receive 13 motivational, individually tailored postcards containing messages to encourage them to attain adequate physical activity during the postintervention period. Girls from the other intervention school (n = 63) did not receive postcards, and those in the control school did not receive any intervention. Moderate-to-vigorous physical activity was measured with accelerometers at postintervention and 9-month follow-up. Girls completed a postcard evaluation survey at 9-month follow-up.

resultsModerate-to-vigorous physical activity decreased significantly from postintervention to 9-month follow-up with no between-group differences or group-by-time interaction effect. On the basis of the survey, 27 (64.3%) girls received all postcards. Only 15 (35.7%) read all that they had received. Evaluations of postcards tended to be favorable. DISCUSSION: Mailed booster postcards to promote physical activity among girls' postintervention were not effective. Strategies to achieve this objective warrant investigation.