Adaptation of left ventricular morphology to long-term training in sprint- and endurance-trained elite runners.

Long-term studies on left ventricular (LV) adaptation have not been reported. The echocardiograms of 41 top-class runners (8 males and 6 females sprint-trained, 15 males and 12 females endurance-trained) were recorded at the beginning and after 1, 2, and 3 years of training. A one-way ANOVA and a linear regression analysis were conducted to determine changes and association between performance and LV values. Training resulted in an increase in performance and LV internal diameter at end-diastole (LVIDd) and decreases in end-diastolic interventricular septal wall thickness, and posterior wall thickness (PWTd). There were no significant differences in LV mass and LV ejection fraction (LVEF, %). The changes in PWTd were linked to enlargement of the LV. In athletes with unusual LV dilatation (>60 mm), LVIDd was related to performance and LVEF was >50%. Maximal wall thickness was <13 mm in all athletes. LV adaptations were independent of sex and type of training and related to the initial level of performance. We believe that LV enlargement in elite runners is a physiological adaptation and that the LVIDd is a predictor of running performance.