Associations between physical fitness, objectively measured physical activity and academic performance

There is evidence that physical activity (PA) can improve the academic performance. We recruited healthy adolescent girls, aged 11–12 years, and measured their PA with the accelerometer ActiGraph GT3X for the consecutive 5 days. Physical fitness (PF) was measured with eight motoric tests and three anthropometry measures. Academic performance (AP) was assessed for the six academic narrated school subjects. The results revealed that the girls were more physically active during the week days and less active at weekend (557 vs. 516 counts/min). Physical education grade shows the highest overall correlations with the results of the PF test battery (r = 0.53–0.95, p < 0.01). Nevertheless, correlations surprisingly decrease for the combined daily PA (r = 0.45), especially the weekend PA (r = 0.28). Grade point average and PF correlated moderately (r = 0.43-0.64), while they were moderate to high for PA (r = 0.59–0.87). Many questions arose after the completion of the present study and several new topics opened up, such as the question of how parental education affects the duration of PA and AP of the children and the influence of the place of residence AP of the children