Background and Purpose
Nationwide, a majority of youth fail to meet current physical activity (PA) recommendations, making physical inactivity among youth an important public health concern (1). While past research has identified several settings (i.e. schools, home, neighborhood, etc.) that impact youth PA levels (2-3), the afterschool environment has recently emerged as an influential setting with the potential to substantially impact youth PA levels (4).  With an estimated 8 million youth (age 5-18 years old) attending ASP in the United States, these programs represent an ideal setting to promote PA among a diverse group of children (5). However, very little is known about ASPs characteristics associated with children’s MVPA and time spent sedentary. The purpose of the current study was to examine the relationship between ASP contextual factors, specifically size of indoor and outdoor play space, type of activity (free play vs. organized PA), program length, and MVPA and time spent sedentary among children attending a diverse sample of ASPs.

Objectives
To examine the association of the ASP contextual characteristics and their relationship with MVPA and time spent sedentary while attending an ASP.

Methods
Twenty ASPs across the South Carolina were selected to evaluate the impact of program contextual factors on children’s PA levels. A total of 1,302 children (5-12yrs, 53% boys) wore accelerometers for 4 non-consecutive days while attending the ASPs. The physical size of the indoor and outdoor play space ASP used each day were measured via a measuring wheel (indoor) and GIS (outdoor), and inventoried via direct observation. The type of activity was evaluated via direct observation using the System for Observing Staff Promotion of Activity and Nutrition and classified as a ratio of free-play (e.g., children released to play on playground and open green spaces) to organized (e.g., adult-led structured games) activity offerings based on the percentage of observational scans during physical activity time either indoors or outdoors. Time allocated for PA opportunities was determined from each ASPs’ daily schedule. PA and sedentary behavior were measured using accelerometers (ActiGraph GT3X models) (6-7). Time (min/d) spent in MVPA and sedentary indoors and outdoors was estimated using built-in light sensors (Lux values) (8). The analysis was conducted only on children attending the ASP for at least 60 minutes on a given day. Children’s MVPA and time spent sedentary (min/d) during indoor and outdoor opportunities were evaluated separately in relation to size of the play space, type of activity provided, and amount of time allocated for PA using mixed model regressions.

Results
Girls and boys accumulated an average of 18.1 and 24.2min of MVPA/d. When comparing indoor and outdoor MVPA, approximately equal portions of activity were accumulated in each activity location. Girls obtained 9.0min of indoor MVPA/d (49.7%) and 9.1mins of outdoor MVPA/d (51.3%), while boys accumulated 12.4min of indoor MVPA/d (51.3%) and 11.8min of outdoor MVPA/d (49.7%). Regarding outdoor MVPA, each additional acre of play space was associated with a 2.8 and 1.5 min/d increase in outdoor MVPA for boys and girls, respectively, and a 2.1 min/d increase in outdoor sedentary behavior for boys. A higher free-play to organized activities ratio was associated with a 3.5 and 3.0 min/d increase in outdoor MVPA for boys and girls, respectively. Examining indoor activity levels, a higher ratio of free-play to organized activities was associated with a 2.4 min/d increase in indoor MVPA for boys. Time spent sedentary indoors increased by 0.5 and 0.7 min/d with each additional increase in 1,000ft2 of indoor activity space for boys and girls, respectively, while a higher free-play to organized activities ratio was associated with a 5.5 and 8.3 min/d increase in indoor sedentary behavior for girls. Length of time allocated for PA during the ASP was unrelated to MVPA and time spent sedentary.

Conclusions
These findings suggest limited influence of the physical size of play space on children’s MVPA and sedentary behaviors during an ASP and that modifiable programmatic structure, in the form of the type of activity opportunities provided (free-play vs. organized games) was related to both MVPA and time spent sedentary. These are important findings, in that increasing physical play space is not a feasible or realistic strategy for ASPs. Conversely, more children were physically active indoors with the presence of more organized activities, yet this was related to a decrease in MVPA. Thus, future studies should develop effective strategies to increase PA levels by taking into account indoor and outdoor play opportunities.

Implications for Practice and Policy
While the ASP play space was associated with children’s PA, the impact of this was minimal. Additional contextual factors impacting ASP youth PA, such as programming high quality PA experiences, are likely to lead to greater improvements in MVPA and reductions in sedentary behaviors. Policies, therefore, should target the PA programming to ensure children are afforded opportunities to be physically active while attending as ASP.

References

1. Troiano RP, Berrigan D, Dodd KW, Masse LC, Tilert T, McDowell M. Physical activity in the United States measured by accelerometer. Med Sci Sports Exerc. 2008; 40(1): 181-188.
2. Davison KK, Lawson CT. Do attributes in the physical environment influence children's physical activity? A review of the literature. International Journal of Behavioral Nutrition and Physical Activity. 2006; 3(19).
3. Ferreira I, et al. Environmental correlates of physical activity in youth – a review and update. Obesity Reviews. 2007; 8(2):129-154.
4. Sallis JF, McKenzie TL. Physical education's role in public health. Res Q Exerc Sport. 1991; 62: 124–137.
5. Afterschool Alliance. America After 3 pm: A Household Survey on Afterschool in America; 2009.
6. Matthews, CE, Chen KY, et al. Amount of time spent in sedentary behaviors in the United States, 2003-2004. American Journal of Epidemiology. 2008; 167(7): 875-881.
7. Evenson, KR, Catellier DJ, et al. Calibration of two objective measures of physical activity for children. J Sports Sci. 2008;26(14): 1557-1565.
8. Flynn JI, Coe DP, Larsen CA, Rider BC, Conger SA, Bassett DR Jr. Detecting Indoor and Outdoor Environments Using the ActiGraph GT3X?+ Light Sensor in Children. Med Sci Sports Exerc. 2013.

Support / Funding Source
NIH: 1R01HL112787