Structural and functional cardiac adaptations to a 10-week school-based football intervention for 9-10-year-old children

The present study investigated the cardiac effects of a 10-week football training intervention for school children aged 9-10 years using comprehensive transthoracic echocardiography as a part of a larger ongoing study. A total of 97 pupils from four school classes were cluster-randomized into a control group that maintained their usual activities (CON; two classes, n=51, 21 boys and 30 girls) and a football training group that performed an additional 3x40min of small-sided football training per week (FT; two classes, n=46, 23 boys and 23 girls). No baseline differences were observed in age, body composition, or echocardiographic variables between FT and CON. After the 10-week intervention, left ventricular posterior wall diameter was increased in FT compared with CON [0.4 +/- 0.7 vs -0.1 +/- 0.6 (+/- SD) mm; P<0.01] as was the interventricular septum thickness (0.2 +/- 0.7 vs -0.2 +/- 0.8mm; P<0.001). Global isovolumetric relaxation time increased more in FT than in CON (3.8 +/- 10.4 vs -0.9 +/- 6.6ms, P<0.05) while the change in ventricular systolic ejection fraction tended to be higher (1.4 +/- 8.0 vs -1.1 +/- 5.5%; P=0.08). No changes were observed in resting heart rate or blood pressure. In conclusion, a short-term, school-based intervention comprising small-sided football sessions resulted in significant structural and functional cardiac adaptations in pre-adolescent children.