The authors investigated, using computer-assisted one-dimensional echocardiography, the influence of systematic two-year sports training on the heart of children engaged in sports (ice hockey n = 20) and a control group of boys not engaged in sports training (n = 25) of the same age (12.6 +/- 0.3 years). At the beginning of the investigation and after two years' training between the two groups no significant differences were found in the following parameters: fractional systolic reduction of the inner diameter of the left ventricle, fractionated systolic enlargement of the interventricular septum, relative width of the left ventricular wall, index of asymetricity of left ventricular hypertrophy and weight of the left ventricle. In none of the investigated parameters the values in sportsmen were beyond the physiological range. The authors did not observe in sportsmen a tendency towards concentric or assymetric hypertrophy of the left ventricle.