Electronic Thesis and Dissertation Repository


Doctor of Philosophy


Health and Rehabilitation Sciences


Dr. Trish Tucker


The overall purpose of this dissertation was to explore young children’s (18 months to 5 years) physical activity and sedentary time. Study 1 assessed the physical activity and sedentary time among a sample of toddlers from London, Canada using two data processing approaches. Study 2 explored the impact of three different early learning environments, and their respective characteristics (e.g., staff behaviours, equipment, sedentary opportunities, etc.), on preschoolers’ activity levels. Study 3 examined differences in two popular accelerometers used to measure young children’s physical activity and sedentary time to better understand measurement discrepancies.

Study 1 revealed that toddlers engaged in 37.27 (SD = 3.79) to 49.40 mins/hr of sedentary time, 9.79 to 18.78 mins/hr of light physical activity (LPA), 0.82 to 3.95 mins/hr of moderate-to-vigorous physical activity (MVPA), and 10.60 to 22.73 mins/hr of total physical activity (TPA), based on the Trost et al. and the Canadian Health Measures Survey cut-points respectively; these rates were significantly different.

The results of Study 2 identified that preschoolers in Full-Day Kindergarten (FDK) accumulated significantly more MVPA (3.33 mins/hr) than those in centre- (1.58 mins/hr) and home-based (1.75 mins/hr) childcare, and significantly more TPA (20.31 mins/hr) than those in centre-based childcare (18.36 mins/hr). For FDK, the Active Opportunities, Sedentary Opportunities, Sedentary Environment, and Fixed Play Environment subscales of the Environment Policy Assessment and Observation (EPAO) tool significantly impacted both MVPA and TPA. For centre-based childcare, only Sedentary Environment was found to impact MVPA and TPA. No subscales were influential of children’s MVPA or TPA in home-based childcare.

The results of Study 3 suggest that, regardless of epoch length, Actical accelerometers, compared with ActiGraph accelerometers, reported significantly higher rates of sedentary time (15s: 42.7 mins/hr vs. 33.5 mins/hr; 60s: 39.4 mins/hr vs. 27.1 mins/hr). ActiGraph accelerometers captured significantly higher rates of MVPA (15s: 9.2 mins/hr vs. 2.6 mins/hr; 60s: 8.0 mins/hr vs. 1.27 mins/hr) and TPA (15s: 31.7 mins/hr vs. 22.3 mins/hr; 60s: 39.4 mins/hr vs. 25.2 mins/hr) in comparison to Actical accelerometers.

In sum, these articles serve as foundational studies for future work in paediatric exercise science and health promotion as well as in the betterment of young Canadians’ health.