Background

There are no prospective studies that would have compared the relationships of different types of physical activity (PA) and sedentary behavior (SB) with academic skills among children. We therefore investigated the associations of different types of PA and SB with reading and arithmetic skills in a follow-up study among children.

Methods
The participants were 186 children (107 boys, 79 girls, 6–8 yr) who were followed-up in Grades 1–3. PA and SB were assessed using a questionnaire in Grade 1. Reading fluency, reading comprehension and arithmetic skills were assessed using standardized tests at the end of Grades 1–3.

Results
Among all children more recess PA and more time spent in SB related to academic skills were associated with a better reading fluency across Grades 1–3. In boys, higher levels of total PA, physically active school transportation and more time spent in SB related to academic skills were associated with a better reading fluency across the Grades 1–3. Among girls, higher levels of total PA were related to worse arithmetic skills across Grades 1–3. Moreover, total PA was directly associated with reading fluency and arithmetic skills in Grades 1–3 among girls whose parents had a university degree, whereas these relationships were inverse in girls of less educated parents.

Conclusions
Total PA, physically active school transportation and SB related to academic skills may be beneficial for the development of reading skills in boys, whereas factors that are independent of PA or SB may be more important for academic skills in girls.

physical activity intervention

The aims of the physical activity intervention are 1) to increase total physical activity to at least two hours per day by increasing different types of physical activity, such as unstructured physical activity, organized sports in sports clubs, structured exercise in exercise clubs, commuting to and from school and physical activity during recess , 2) to increase the versatility of physical activity to develop physical, psychic, emotional, cognitive and social skills and functions, 3) to provide a variety of positive physical activity experiences to help each child find a suitable type of physical activity and to be able to enjoy exercise on the long-term, 4) to decrease sedentary behaviors, such as watching television and playing on computer, to a maximum of two hours per day and 5) to increase energy consumption to maintain energy balance and to prevent overweight. The children and their parents in the intervention group met our physical activity specialist seven times during the two-year intensive intervention period. The physical activity counseling visits occurred at baseline and 1.5, 3, 6, 12, 18 and 24 months after the baseline visit. Our physical activity specialist gave the children and their parents detailed and individualized instructions on physical activity and sedentary behavior to promote health and wellbeing. The children were offered a possibility to participate in exercise clubs, supervised by our trained exercise instructors, in the afternoons after school once a week. We will continue a less intensive physical activity intervention until adulthood.  The physical activity intervention has been planned to comply with the Finnish physical activity recommendations for children.
diet intervention

The aims of the diet intervention are 1) to decrease the intake of saturated fat and to increase the intake of unsaturated fat, 2) to increase the consumption of vegetables, fruit and berries, 3) to increase the consumption of foods containing lots of fibre, such as whole-grain products, 4) to decrease the intake of sugar and salt and 5) to avoid excess energy intake to prevent overweight among children and their parents. The children and their parents in the intervention group met our authorized nutritionist seven times during the two-year intensive intervention period. The diet counseling visits occurred at baseline and 1.5, 3, 6, 12, 18 and 24 months after the baseline visit. The nutritionist gave the children and their parents detailed and individualized instructions on diet to promote health and wellbeing. The children and their parents were also encouraged to participate in cooking clubs, supervised by nutritionists, where they were instructed to cook healthy meals and snacks. We will continue a less intensive diet intervention until adulthood. The diet intervention has been planned to comply with the Finnish nutrition recommendations.