Recent studies showed contrasting findings in morphological changes due to competitive soccer in adolescent players (SP). We present a prospective study in 315 consecutive adolescent (10-14 years) male elite SP and 53 healthy matched active controls (CON). All participants underwent a complete transthoracic two-dimensional echocardiography (TTE). The mean age in SP was 12.8 ± 0.65 years compared to 12.6 ± 0.8 years in CON. For all left ventricular (LV) dimensions, mean Z-score values were higher in SP. There was a significant Z-score increase in interventricular septum diastolic diameter (2.47z vs. 1.62z, p < 0.05), left ventricular posterior wall diastolic and systolic diameter (1.15z vs. 0.47z, p < 0.05 and 1.05z vs. - 0.4z, p < 0.05). Athletes had significant greater LV mass indexed for BSA (94 ± 12 g/m2 vs. 81 ± 13 g/m2, p < 0.05). There was no significant difference in LV function or diameters. Conclusion: Our findings suggest that elite soccer training in adolescent male is a type of sport predominantly related to cardiac resistance remodeling. Adolescent SP may develop supernormal left ventricular wall dimensions (+ 2.0 to + 2.5z). If in SP Z-scores, any LV dimension above + 2.5 is measured, primary or secondary cardiomyopathies should be excluded. What is Known: • Morphological cardiac adaptation in response to exercise depends on the type, duration, and intensity of training. • Morphological and functional changes due to competitive sports (athlete's heart) occur even in pre-adolescent athletes. What is New: • Our findings point out that German elite soccer training in adolescent male (10-14 years of age) is a type of sport predominantly related to cardiac resistance remodeling. • If in an adolescent competitive soccer player any LV dimension Z-score value above + 2.5 is measured, a primary or secondary cardiomyopathy should be excluded.
Keywords: Adolescent; Athletes; Echocardiography; Soccer; Sudden cardiac death; Z-scores.