Does Objectively Measured Physical Activity Intensity During School Differ by Level of Aerobic Capacity and Demographics Among Elementary Students?

Abstract

PURPOSE: The purpose of this study is to examine if the amount and intensity of objectively measured physical activity (PA) differs by level of aerobic capacity and gender, socio-economic status (SES), and race among 4th grade children. METHODS: Participants included 1859 4th graders from 26 central Texas elementary schools (m age=9.5; 48.5% female; 54.7% white) across 3 years. Aerobic capacity was dichotomized based on if their Pacer score was in the Healthy Fitness Zone (HFZ) for the FitnessGram. Percent of time spent in sedentary (S), light- (L), moderate- (M), and vigorous- (V) intensity PA were assessed during the school day for one week via accelerometers. Gender and race (white, non-white) were also taken from FitnessGram data. Socio-economic status (SES) was assessed by eligibility for free or reduced lunch. A MANOVA was run to examine differences between HFZ status and percent of time spent in S, L, M, and V PA. RESULTS: The MANOVA showed a main effect for HFZ status on PA (p<.001); where children in the HFZ for Pacer had lower levels of S (p.20). There was a significant interaction between HFZ and SES (p < .01). For those in the HFZ, higher SES students spent more time in V(d=.27), but were no different than lower SES students in S, L, or M. For those not in the HFZ, lower SES students spent more time in S (d=.33), and less in L (d=-.37) than did higher SES students. CONCLUSIONS: Children in the HFZ spent more time in MVPA. Males spent more time being active compared to females. For those not in the HFZ, low SES is associated with more time in S and less time in L. For HFZ, low SES is associated with lower levels of V PA. These data extend existing research comparing pacer scores with objective measures of activity to children. Results indicate that interventions that target this age may need to be tailored to girls and those lower in SES. NIH R01HD070741