Summary.-The 42 members of a university track team were Ss in a comparative study of those athletes classified as sprinters and those classed as runners. The two groups were compared on 28 physiological and behavioral variables, including height, weight, body surface, metabolism rate, respiration rate, vital capacity, blood pressure, pulse rate, vertical jump, reaction time, scholastic aptitude, reading ability, and grade-point average. Greatest differences were found in measures of pulse rate (especially those observed after periods of vigorous physical activity), in vital capacity, and in vertical jump ability. Distance runners tended to be somewhat taller but lighter than sprinters and to surpass sprinters on most measures of scholastic aptimde and achievement. Track is so much a sport of specialized events that many participants and spectators think of it not in a generic sense but as a series of distinct and only nominally related sports activities. Comments of college track athletes and coaches make it particularly clear that there is a sharp distinction between concepts of on the one hand and on the other. Few college track athletes seriously train and compete in both and sprinting events, and most have come to view themselves quite rigidly in one category or the other well before reaching college age. Coaches and recruiters, too, us~~ally refer to runners and sprinters as if the two are categories which are mutually exclusive. The roles seem to be nearly as sharply distinguished as those of the lineman and back in football, and yet the bases are far less conspicuous in crack events than in football and some other sports. Just what are the characteristics that distinguish the runner from the sprinter at the college level of uack competition? It is this question that the research reported in this paper attempted to answer. METHOD Subjects Forty-two track athletes on the varsity and freshman squads of one university were studied. Each S was classified as runner or sprinter on the basis of the event or events for which he was training and competing. Those engaged in running events one-half mile or more in length were classified as distance runners, while those participating in running events of shorter length were classed as sprinters. The category of sprinting included those competing in relays and hurdling as well as those in the dashes. Competitors in field and jumping events were excluded. By the criteria described above, 15 members of the track team were classi