There is a known relationship between total physical activity (PA) and weight status in children; however, there is a paucity of data examining the prospective relationship between school day PA and obesity among rural elementary school children. A large number of cross-sectional studies have demonstrated that higher levels of PA are inversely associated with overweight and obesity in children. Longitudinal studies examining the prospective relationship between PA and weight status typically rely upon PA and weight data collected through the use of proxy measures (e.g., self-report), not objectively measured data. The majority of children spend around half of their waking hours in the school environment and as such, it is critical to understand how and when children are active at school. A review of school-based policies identified physical education (PE), classroom-based PA (CBPA), and recess as three of the primary intervention categories for increasing PA in children. It has been shown that rural children have greater odds of being obese and yet there is a lack information on how children in rural schools are accruing PA. The research presented in this dissertation narrows the identified research gaps about our understanding of the relationship between the rural school environment, PA, and children’s weight status.
To address the first aim in this dissertation, we assessed the prospective relationship between baseline PA and future weight status in rural elementary school children. Objectively measured height and weight data were collected with pedometer data in 866 rural elementary school children. Linear models were used to evaluate the association between baseline PA and future BMI. Our results indicated that baseline BMI is the strongest predictor of future BMI whereas there is no association between baseline PA and future BMI after controlling for baseline BMI. This relationship did not vary by age, sex, or school.
To address the second aim, we quantified school-day activity levels during various PA opportunities (i.e. CBPA, recess, PE) and evaluated the relationship between PA opportunities and children’s PA levels during the school day. Children from 1st, 3rd, and 5th grade were invited to participate and accelerometer data was collected on 230 children. Classroom schedules were provided by teachers and timestamped data from accelerometers were matched to the classroom schedules. Children accrued a mean of 27.5 minutes of moderate to vigorous PA (MVPA) during the school day and boys were more active than girls in our sample. We observed an interaction between PA domain and grade as the percentage of time in MVPA across domains varied by grade. Children were not meeting the recommended percentage of time in MVPA for PE or recess (≥ 50%). Only 10% of time during CBPA opportunities was spent in MVPA.
Results from these studies suggest that baseline school day PA is not associated with future BMI and that baseline BMI is the best predictor of future BMI. PA patterns during school day PA opportunities varies by sex and grade with boys being more active than girls across all domains. Although results from this dissertation help fill in research gaps, additional exploration of 1) casual effects of weight change in rural elementary school children, and 2) identifying strategies to increase MVPA during the school day PA opportunities are warranted.