Follow-Up Study of Objectively Measured Physical Activity Levels in 3- to 4-year-old Finnish Children

Introduction In previous studies, most of which were cross-sectional, age has been found to associate with physical activity (PA). The aim of the present study was to evaluate whether the PA of 3-year-old children changed over the course of a one-year follow-up.

Methods Physical activity levels of children born in 2007 were assessed during two measurement periods: from August to October in 2010 and in 2011. The accelerometer (ActiGraph GT3X) data was collected on 5 consecutive days (3 weekdays and 2 weekend days). Valid, 8h/d, PA data for at least 3 days (2 weekdays and 1 weekend day) were obtained from 46 children (23 boys) in both years. During the first measurement the children were 39 (4) months old and during the second 50 (4) months old. Parents were instructed to keep the accelerometers on their children’s hip during all waking hours except during water-based activities. The cut-points established by van Cauwenberghe (2010) and 5-second epoch duration were used in this study. The Mann-Whitney U-test and Independent t-test were applied to identify differences between genders, weekdays and age.

Results Overall daily PA was calculated as mean counts per minute (cpm) for genders, weekdays, weekend days and both measurement sections separately. The overall PA was significantly higher among 4-year-old children (735±148 cpm) than among 3-year-olds (618±121cpm).

Discussion Children were physically more active at the age of 4 than 3 on average, and boys were more active than girls at the age of 4. Girls’ lower activity levels on weekends are inconsistent with previous studies. Only few previous studies have reported an increase with age in children under school age (Jackson et al. 2003). The reason for this inconsistency between the results remains unclear, but it may be due to interindividual variation. Gender segregation seems to begin early in childhood.

References Jackson D, Reilly J, Kelly L, Montgomery C, Grant S & Paton J (2003) Obes Res, 11(3):420–5. Van Cauwenberghe E, Labarque V, Trost S, De Bourdeadhuij I & Cardon G (2010) Int J of Pediatr Obes, Early Online, 1–8