1. Results Baseline and Post-Intervention MVPA values by Season Table 1. Descriptive statistics of MVPA levels. N = Number of participants in each seasonal category of groups. Mean (SD) = Number of minutes engaged in MVPA. ANOVA revealed significant between-group differences for baseline MVPA (F (3, 148) = 2.85, p<.05), but not post-intervention (F (3, 63) = 0.52, p<.05). Between-Group Differences in MVPA: Baseline and Post-Intervention Table 2. Between-group differences testing. Results of between-group t-tests at baseline and post- intervention. Negative t values represent lower mean MVPA values of first seasonal group. Higher t values represent higher mean MVPA values of second group. Winter groups were significantly less active at baseline than Spring (t (90) = -2.68, p<.01) and Summer groups ( t (80) = -2.83, p <.01). Exploring Physical Activity Outcomes from a Pediatric Obesity Intervention: Does Season of the Year Matter? Kelsey Borner MA 1,2, Katrina M Poppert 1,2, Cathleen Odar Stough MA 1,2, Kelsey Dean MS RD LD 1, Meredith Dreyer Gillette PhD 1,3 Susana Patton PhD 1,4 Ann M Davis PhD MPH ABPP 1,4 1 Center for Children’s Healthy Lifestyles & Nutrition, Kansas City, Missouri 2 University of Kansas, Clinical Child Psychology Program, Lawrence, Kansas 3 Children’s Mercy Hospitals and Clinics, Kansas City, Missouri 4 Department of Pediatrics, The University of Kansas Medical Center Background Physical activity (PA) promotion is a critical component of physical obesity interventions, but studies show inconsistent changes to PA post-intervention (Cliff et al., 2010). One reason for this may be due to seasonal changes in PA, since youth are naturally less active during the winter versus spring and summer months (e.g., Rowlands et al., 2009; Belanger et al., 2009). However, the science examining a seasonal impact on PA within pediatric obesity interventions is lacking. The current study examines moderate-to-vigorous PA (MVPA) levels and changes in MVPA according to season of start date (i.e., Winter, Spring, Summer, Fall) using PA data gathered from youths participating in a 12-week family-based behavioral group (FBBG) pediatric obesity intervention. Conclusions There may be a seasonal impact on patterns of PA among youths participating in pediatric obesity interventions, indicating that interventions should consider describing PA outcomes by season, echoing the call of Cliff and colleagues (2010) for more evidenced-based approaches to PA. Given the relationship between time spent outside and PA, future interventions should modify PA promotion strategies to account for seasonal differences. As we continue to build this literature toward evidenced-based PA, future interventions should consider: 1) Utilizing modern techniques for accounting for missing data to account for participant attrition, and 2) Analyzing changes in MVPA levels dependent on levels discretionary time to account for differences in availability of discretionary time for PA (i.e., in school versus out of school). Acknowledgments The authors wish to thank the parents and children who participated in our interventions and contributed the data for the current analyses. We would also like to acknowledge funding from the Health Care Foundation of Greater Kansas City, the Kansas City YMCA, and the The Junior League of Kansas City, Missouri. For more information contact: For more information contact: Kelsey Borner, M.A.; 2020 Dole Human Development Center, 1000 Sunnyside Avenue Lawrence, KS 66045; kborner@ku.edu Methods Participants 142 children between the ages of 5 and 18 (M=10.36; SD=2.81 years) Baseline BMI Percentile=97.58, SD=3.05; Baseline BMI z-score=2.19, SD=0.46 Participants were 51% female and represented a variety of races (46.30% African American, 28.40% Caucasian, 22.22% Latino, 3.09% other). Measures Physical Activity. The ActiGraph Actometer (Actigraph LLC, Pensacola, FL) measured MVPA with 60-second epochs. Participants wore the monitors on the non-dominant hip for 7 days; valid days included at least 6 hours of wear time. The two weekdays and one weekend day with the greatest amount of valid wear time were used for analyses. Minutes of moderate, vigorous, and very vigorous activity were combined to create MVPA as a single variable; minutes of MVPA were adjusted for wear time. Intervention and Procedures Healthy Hawks (Davis et al., 2013) is a 12-week FBBG with concurrent parent and child weekly sessions (conducted in English or Spanish), which include behavioral, nutrition, and exercise education, as well as supervised physical activity. 20 Healthy Hawks groups were conducted between April 2006 and January 2013. Participants were recruited at health fairs and community events; eligible children had a BMI over the 85 th percentile. Results Continued Within-Group Differences in MVPA from Baseline to Post-Intervention Table 3. Results of within-group difference testing. N = Number of participants in each seasonal category of groups. Mean (SD) = number of minutes engaged in MVPA. Most seasonal groups decreased MVPA levels from baseline to post-intervention and Spring groups significantly decreased MVPA following intervention (t (17) = 2.86; p <.01). Winter groups increased MVPA over course of intervention (n.s.). BaselinePostPaired Samples Test NMean (SD)N tdfp Spring1855.426 (46.96)1836.907 (34.51)18.52 (27.52)2.85517.011 Fall859.71 (24.19)840.63 (23.65)19.08 (27.98)1.9297.095 Winter1230.53 (22.24)1238.83 (37.03)-8.31 (31.12)-.92511.375 Summer1657.35 (49.58)1655.71 (35.83)1.67 (21.64).30815.762 References Cliff, D. P., Okely, A. D., Morgan, P. J., Jones, R. A., & Steele, J. R. (2010). The impact of child and adolescent obesity treatment interventions on physical activity: a systematic review. Obesity reviews, 11(7), 516-530. Rowlands, A. V., Pilgrim, E. L., & Eston, R. G. (2009). Seasonal changes in children's physical activity: an examination of group changes, intra-individual variability and consistency in activity pattern across season. Annals of human biology, 36(4), 363-378. Bélanger, M., Gray-Donald, K., O'loughlin, J., Paradis, G., & Hanley, J. (2009). Influence of weather conditions and season on physical activity in adolescents. Annals of epidemiology, 19(3), 180-186. Davis, A. M., Daldalian, M C., Mayfield, C. A, Dean, K., Black, W. R., Sampilo, M. L., Gonzalez-Mijares, M., & Suminski, R. (2013). Outcomes from an Urban Pediatric Obesity Program Targeting Minority Youth: The Healthy Hawks Program. Childhood Obesity, 9(6), 492-500. Data Analysis Between group differences were analyzed by one-way ANOVAs and independent samples t-tests. Within-group changes (from baseline to post-intervention) were analyzed by paired-samples t-tests. Four seasons (Spring, Summer, Fall, Winter) were determined by groups’ baseline start date according to calendar cut-offs for appropriate years. BaselinePost SeasonNMean (SD)N MVPA Spring5455.28 (42.39)2250.92 (64.23) MVPA Fall1651.27 (27.18)1136.67 (25.06) MVPA Winter3835.77 (27.40)1841.35 (34.56) BaselinePost tdfpt p Winter vs. Spring-2.67990.009-.56838.574 Winter vs. Summer-2.82765.006-1.18832.243 Winter vs. Fall-1.90252.063.39027.699 Spring vs. Summer-.69196.491-.26836.790 Spring vs. Fall.35768.723.70531.486 Summer vs. Fall1.01351.3161.52125.141