A sound children's mind in a healthy children's body

oftheRomanpoetJuvenal(∼60–127AD). Juvenal’s intention with this phrase wasrather to teach his fellow Roman citizensthe right virtues worth praying for, thanmaking any scientiﬁc statement about theimpact of physical activity on the humanmind. But Juvenal’s phrase interpreted inthe latter context has turned true in lightof growing evidence from neurocognitiveresearch suggesting that physical ﬁtnessindeed enhances cognitive function (for areview see Hillman et al., 2008). A more recent but even more impor-tant question is how physical activity andtraining may inﬂuence the developingbrain during periods in which the brainmatures, learns and forms connections(Amso and Casey, 2006). In adult animalsand humans, physical exercise was in factshown to inﬂuence the brains cellular andmolecular layout by stimulating neuroge-nesis (e.g., transiently elevating levels ofbrain-derived neurotrophic factor impor-tant for brain plasticity and behavior)in brain regions like the hippocampus,known to underpin memory formation(for a review see Voss et al., 2013). Research like this in children is funda-mentalforthedevelopmentofappropriateeducational concepts optimally embed-ding sport activities into children’s schoolday. Reality however speaks a differentlanguage, since even in light of previ-ous research indeed suggesting improvedcognitive function with enhanced physi-cal ﬁtness (see e.g., Hillman et al., 2009;Pontifex et al., 2011; Voss et al., 2011;Chaddock et al., 2012), opportunities forphysical activities for children are progres-sively reduced, not only in school but alsoaround their home environment (Troianoet al., 2008). At the same time, societyis seeking for young sport talents in soc-cer, football, basketball, hockey, and otherfamous sports, progressively establishing aselection process segregating children intoan inactive group, receiving more schoolclass and less sport education, from thosetalents being intensively trained for a pos-sible professional sport career.That this development in sport edu-cation might be misleading was alreadysuggested by a number of recent cross-sectional studies showing improvedcognitive function with enhanced phys-ical ﬁtness (see e.g., Hillman et al.,2009; Pontifex et al., 2011; Voss et al.,2011; Chaddock et al., 2012). The study“The effect of physical activity on func-tional MRI activation associated withcognitive control in children: a random-ized controlled intervention” by LauraChaddock-Heyman and colleagues hasgained a large community-wide inter-est after publication, since it is the ﬁrstlong-term interventional functional MRIstudy addressing the open question howphysical activity inﬂuences cognitivecapacity together with the function ofspeciﬁc prefrontal regions in children. Thestudy published in Frontiers in HumanNeuroscience in March 2013 is the conse-quent next step in this research ﬁeld, sincethe cross-sectional studies conducted sofar bear the risk that instead of the physi-cal training itself, other hidden systematicbetween-group factors, such as genesandnutrition,mayexplainwhyphysi-cally active children outperformed theirlower ﬁt peers on tasks of cognitive con-trol (Hillman et al., 2009; Pontifex et al.,2011; Voss et al., 2011; Chaddock et al.,2012). Furthermore, only a few studieson children have combined cognitive test-ing with brain imaging to examine howphysical activity and aerobic ﬁtness relateto brain processes of enhanced cognitivefunction (Hillman et al., 2011). Recentevidencefromthefewbrainimagingstud-iespublishedsofarsuggestreducedneuralactivity in the prefrontal cortex togetherwith improved cognitive function in chil-dren with higher aerobic ﬁtness levels(Chaddock et al., 2011; Voss et al., 2011). These ﬁndings are in agreement withstudies comparing adult’s with children’scognitivecontrolcapacitiesdemonstratingreduced activity in the frontal cortex ofadults coupled with enhanced cognitiveperformance (see e.g., Diamond, 2006;Bunge and Crone, 2009). The study design used by Chaddock-Heyman and colleagues acknowledgesthese previous studies also when account-ing for the two main problems that occurwhen investigating the developing brain:First, an interventional study involvingchildren over a longer time period needsto control for the “normal” progress in