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Seasonal Variation in Objectively Measured Physical Activity Among Finnish Boys and Girls Aged 7 to 15 Years
- Presented on 24 October 2012
Aim The aim was to evaluate seasonal variations in physical activity. This study is part of the pilot phase of the Finnish Schools on the Move program in 2010-2012.
Methods The study population consisted of 119 boys and girls from grades 1 to 9 (7 to 15 years of age) from 6 schools. Children’s physical activity was monitored four times over the 1.5-year follow-up period: in autumn 2010, spring 2011, autumn 2011, and spring 2012. Physical activity was assessed objectively using the ActiGraph accelerometer for 7 consecutive days. The cut-off value of 2,296 counts per minute  was used for moderate-to-vigorous physical activity (MVPA). Seasonal variations in MVPA time, and the proportion of children meeting Finnish recommendations of at least 60 minutes of MVPA/day , were analysed. The results were examined as a whole group and in two age-groups: younger (grades 1-6) and older (grades 7-9) children.
Results Mean MVPA time was 55 min/day in autumn 2010 and 52 min/day in autumn 2011. In spring 2011 and spring 2012, mean MVPA times were 60 and 56 min/day, respectively. The difference in MVPA time between autumn and spring was 4 min/day, which equals 8% of MVPA time (p<0.005 for seasonal difference). The percentage of children meeting the 60 minutes of MVPA/ day in autumn was 39% in 2010 and 34% in 2011; in spring the respective values were 48% in 2011 and 40% in 2012. The results were similar in both genders and age-groups. On average, younger children had 22 min/day more MVPA time than older children (p<0.001). For younger children there was no seasonal difference in weekend MVPA times.
Conclusions Finnish school-aged children are more active in spring than in autumn. The mean difference in MVPA time between these two seasons was 4 min/day, meaning 8% of total MVPA time.
References  Evenson, K.R.; Catellier, D.J.; Gill, K.; Ondrak, K.S. and McMurray, R.G. Calibration of two objective measures of physical activity for children. Journal of sports sciences, 2008. 26(14), 1557.  Tammelin, T. and Karvinen, J. (editors). Physical activity recommendations for school-aged children. Finnish report, abstract in English. 2008. Opetusministeriö ja Nuori Suomi ry. Reprotalo Lauttasaari Oy, Helsinki.