We have previously demonstrated increased voltage of septal, right and left ventricular depolarization in 1,299 athletic students compared to 151 sedentary controls. In the present investigation we have studied the prevalence of hypertrophy and the correlation between hypertrophy and other ECG findings. An increase of Q waves of more than 0.2 mV was associated with increased indices of right and left ventricular hypertrophy. Right ventricular hypertrophy was associated with an increased prevalence of incomplete right bundle branch block and increased parameters of septal and left ventricular hypertrophy. Left ventricular hypertrophy was associated with increased indices of septal and right ventricular hypertrophy and with bradycardia. Furthermore, left ventricular hypertrophy was characterized by ST elevation and increased T wave amplitudes, but not by repolarization abnormalities. Thus, our data point to a harmonious hypertrophy. Based on our findings we suggest the following normal limits in young people (20-30 years) according to the 97.5 percentile regarding the Sokolow index: for athletic students 5.3 (males) and 3.6 mV (females), for sedentary controls 4.0 (males) and 3.6 mV (females). It remains to be clarified whether these values are also valid in top athletes.