To proceed with the finding, the researchers assigned 408 participants from the Gothenburg region to two hours of extra play and motion activities per week, in collaboration with a local sports club. This was twice the normal amount of curricular physical activity.
The schools were chosen carefully for this study and the scientists highlighted that they are comparable with respect to the number of boys and girls, the fraction of pupils with foreign background and the average level of income, unemployment and education of parents.
The effect of the intervention was assessed by comparing the achievement of the national learning goals by the children four years prior and five years after the implementation. They then compared the results to the control groups in three schools that did not receive extra physical activity.