The purpose of this study was to analyze morphological and functional changes in the left ventricular muscle mass and vessel diameters of the arteries in young competitive athletes of various sports and evaluate the correlation between the heart and arterial vessel under the training environment in this latter half of the growth period. The subjects were 51 male college student athletes (mean age, 19.6±0.4 years) of 6 competitive sports (archery, weight lifting, swimming, short-distance races, middle-distance races, and long-distance races) . The diameters of the right and left common carotid arteries, right and left radial arteries, right and left foot dorsal arteries, and the aorta and the left ventricular muscle mass (LVM) were measured by Doppler echocardiography. To minimize the influences of the physique and body weight associated with growth and sport types, all data obtained by measurement were corrected by body surface area. The sum of the diameters of all the above arteries (total arterial diameter : TAD) was obtained to evaluate its correlation with the left ventricular muscle mass. The diameter of the foot dorsal artery was significantly higher in the long-distance runners than in the sprinters (P<0.05) . The diameter of the radial artery according to the 6 types of sport was the highest for weight lifting, followed in order by archery, longdistance races, middle-distance races, swimming, and short-distance races, showing a significant difference between weight lifting and short-distance races (P<0.05 ) . TAD was high for generalized endurance sports and correlated with the left ventricular muscle mass (r=0.893) . Thus, the arterial diameters significantly differed among competitive sports and were particularly increased for endurance exercise. The diameters of the local arteries used for local exercise were also increased. When TAD as a new parameter and its ratio per body surface area were calculated, there was a high correlation between the heart (left ventricular muscle mass) and the arterial diameter. These results suggest that exercise adaptation can he evaluated in the arterial system in svstemic circulation as well as the nervous and muscular systems.