Purpose: To investigate patterns of activity and inactivity in a birth cohort of children followed from 3 to 5 yr and to investigate whether changes in activity occurred over time.
Methods: Two hundred and forty-four children (44% female) were seen annually at 3, 4, and 5 yr. Physical activity and inactivity was measured by questionnaire (parent-proxy) and by Actical accelerometers for five consecutive days (24-h monitoring) each year in children and once in each parent for 7 d (69% with data).
Results: Retention of participants was high (92%). Viable accelerometry data were obtained for 76-85% of children at each age. Reliability estimates ranged from 0.80 (3 yr) to 0.84 (5 yr). Day of the week, season, sex, hours of childcare, or birth order did not affect daily average accelerometry counts (AAC) at any age. Parental activity correlated weakly with the child's activity at 3 and 4 yr (r values = 0.17-0.28), but only the father's activity remained a significant predictor of the child's activity after adjustment for confounders. Children spent approximately 90 min.d in screen time (television, videos, DVD, and computers) with an additional 90 min in other sedentary activities (reading, drawing, and music). Physical activity was significantly reduced at 4 and 5 yr compared with 3 yr in both sexes, whether measured as AAC (24-h data, awake time only, weekend days, weekdays), time in moderate or vigorous activity, or from parental reports of activity.
Conclusion: Levels of physical activity declined in boys and girls between the ages 3 and 4-5 yr, whether using objective measures or parental reports of activity.