Association of environment and policy characteristics on children's moderate-to-vigorous physical activity and time spent sedentary in afterschool programs.

BACKGROUND Afterschool programs are an important setting in which to promote children's physical activity. This study examines the association of environmental and policy characteristics on the moderate-to-vigorous physical activity and sedentary behavior of children attending afterschool programs. METHODS A total of 1302 children attending 20 afterschool programs across South Carolina wore accelerometers (ActiGraph GT3X+) for up to 4non-consecutive days. Policy-level characteristics were evaluated using the Healthy Afterschool Program Index-Physical Activity scale. Physical activity space was measured using a measuring wheel (indoor, ft(2)) and Geographical Information Systems software (outdoor, acres). The structure (free-play or organized) of activity opportunities was evaluated via direct observation. Time spent in moderate-to-vigorous physical activity and sedentary, both indoors and outdoors, was estimated using accelerometry. RESULTS For every 5000 ft(2) of utilized indoor activity space an additional 2.4 and 3.3 min/day of sedentary behavior was observed among boys and girls, respectively. A higher ratio of free-play to organized play was associated with higher indoor sedentary behavior among boys and girls (3.9 min/day and 10.0 min/day, respectively). For every 1 acre of outdoor activity space used, an additional 2.7 min/day of moderate-to-vigorous physical activity was observed for boys. A higher free-play to organized play ratio was associated with higher outdoor moderate-to-vigorous physical activity for boys and girls (4.4 and 3.4 min/day increase, respectively). Policy characteristics were unrelated to moderate-to-vigorous physical activity levels and time spent sedentary. CONCLUSION Findings indicate that policies and size of activity space had limited influence on moderate-to-vigorous physical activity and sedentary behavior, suggesting that a programmatic structure may be a more effective option to improve moderate-to-vigorous physical activity levels of children attending afterschool programs.