Physical activity levels across the early primary years

Purpose: To examine physical activity levels in kindergarten and grade 2 in cross-sectional cohorts and a longitudinal sample.

Methods: Ninety-six kindergarten children (Mage=5y 7m, 58% boys) from 8 British Columbia schools participated in 2010-11, and 101 grade 2 children (Mage=7y 9m, 52%, boys) participated in 2012-2013. A sub-cohort of 21 children were tracked from kindergarten to grade 2. Physical activity (PA) was assessed for 7 days in kindergarten and grade 2 using Actigraph GT1M accelerometers.

Results: Comparing the kindergarten and grade 2 cohorts using independent t-tests, PA levels (Light PA and MVPA) were significantly lower in grade 2 and sedentary behaviour was significantly higher, specifically: Light PA = 220 and 186 min/day, MVPA = 134 and 100 min/day, and sedentary behaviour = 367 and 439 min/day. Repeated measures ANOVA revealed a similar pattern for the tracking sample. On average, children participated in 31 fewer min/day of Light PA, 42 fewer min/day of MVPA, and 68 more min/day of sedentary behaviour in grade 2. All differences were significant at p<.001. Tracking correlation coefficients (ICCs) over the two years were: .59, .30, and .77 for total PA, MVPA, and sedentary behaviour, respectively.

Conclusions: Both the cross-sectional cohorts and the longitudinal cohort revealed that in grade 2 PA levels were lower by approximately 60 min/day, with a concomitant increase in sedentary behavior. A greater understanding of the determinants of this concerning trend, as well as investigation of approaches to help children maintain higher PA levels across these early primary years, are needed.