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 MA1,2, Katrina M Poppert 1,2, Cathleen Odar Stough MA1,2, Kelsey Dean MS RD LD1, Meredith Dreyer Gillette PhD1,3 Susana Patton PhD1,4 Ann M Davis PhD MPH ABPP1,4

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 4Department 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).

AcknowledgmentsThe 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: Kelsey Borner, M.A.; 2020 Dole Human Development Center, 1000 Sunnyside Avenue Lawrence, KS 66045; kborner@ku.edu

MethodsParticipants• 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 85th percentile.

Results ContinuedWithin-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.).

 Baseline Post Paired Samples Test

N Mean (SD) N Mean (SD) Mean (SD) t df p

Spring 18 55.426 (46.96) 18 36.907 (34.51) 18.52 (27.52) 2.855 17 .011

Fall 8 59.71 (24.19) 8 40.63 (23.65) 19.08 (27.98) 1.929 7 .095

Winter 12 30.53 (22.24) 12 38.83 (37.03) -8.31 (31.12) -.925 11 .375

Summer 16 57.35 (49.58) 16 55.71 (35.83) 1.67 (21.64) .308 15 .762

ReferencesCliff, 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.

  Baseline Post

Season N Mean (SD) N Mean (SD)

MVPA Spring 54 55.28 (42.39) 22 50.92 (64.23)

MVPA Fall 16 51.27 (27.18) 11 36.67 (25.06)

MVPA Winter 38 35.77 (27.40) 18 41.35 (34.56)

 Baseline Post

t df p t df p

Winter vs. Spring -2.679 90 .009 -.568 38 .574

Winter vs. Summer -2.827 65 .006 -1.188 32 .243

Winter vs. Fall -1.902 52 .063 .390 27 .699

Spring vs. Summer -.691 96 .491 -.268 36 .790

Spring vs. Fall .357 68 .723 .705 31 .486

Summer vs. Fall 1.013 51 .316 1.521 25 .141