Child Health and Exercise Program, McMaster University and McMaster Children's Hospital, Chedoke Site, Evel Building, Room 469, 555 Sanatorium Road, Hamilton, ON L8N 3Z5, Canada.
Early childhood is a critical period for the development of active living behaviours; however, very little is known about the physical activity levels of preschoolers from Canada. The objectives of this study were to (i) examine physical activity in a sample of Ontario preschoolers by using high-frequency accelerometry to determine activity and step counts; (ii) assess the relationship between step counts and physical activity; (iii) examine the influence of epoch length or sampling interval on physical activity; and (iv) compare measured physical activity to existing recommendations. Thirty 3- to 5-year-old children wore accelerometers to monitor habitual physical activity in 3-s epochs over a 7-day period. Preschoolers engaged in an average of 220 min of daily physical activity, 75 min of which were spent in moderate-to-vigorous physical activity (MVPA), and they accumulated 7529 ± 1539 steps·day(-1). Preschoolers who engaged in more MVPA also took more steps on a daily basis (r = 0.81, p