• The study sample included 8,061 children from the Northern Finland Birth Cohort 1986.   Baseline data included parent-reported motor function at age 8 years old.  This was then compared with self-reported physical activity, predicted cardiorespiratory fitness (cycle ergometer test), obesity (body weight and height), and academic achievement (grades) at age 16 years old.
• Structural equation models with unstandardized (B) and standardized (β) coefficients were used to test whether, and to what extent, physical activity, cardiorespiratory fitness, and obesity at age 16 mediated the association between childhood motor function and adolescents’ academic achievement.
• Physical activity was associated with a higher grade-point average, and obesity was associated with a lower grade-point average in adolescence.
• Furthermore, compromised motor function in childhood had a negative indirect effect on adolescents’ academic achievement via physical inactivity (B = –0.023, 95% confidence interval = –0.031, –0.015) and obesity (B = –0.025, 95% confidence interval = –0.039, –0.011), but not via cardiorespiratory fitness.
•  These results suggest that physical activity and obesity may mediate the association between childhood motor function and adolescents’ academic achievement.
• Compromised motor function in childhood may represent an important factor driving the effects of obesity and physical inactivity on academic underachievement.

Marko T. Kantomaa, Emmanuel Stamatakis, Anna Kankaanpää, Marika Kaakinen, Alina Rodriguez, Anja Taanila, Timo Ahonen, Marjo-Riitta Järvelin, and Tuija Tammelin. (2013). Physical activity and obesity mediate the association between childhood motor function and adolescents’ academic achievement. PNAS 2013 110(5), 1917-1922. doi: 10.1073/pnas.1214574110