The oxygen uptake - work-output relationship of runners during graded cycling exercise: sprinters vs. endurance runners.

In order to study oxygen consumption (VO2) for a given work load at the exhaustive level of a graded cycling exercise in well-trained runners, a progressive cycle ergometer exercise test was performed on 9 sprinters and 12 endurance runners, all in good national standing; 12 sedentary men served as control subjects. The relationship between VO2 and work-output appeared to be linear in most of the subjects, but a plateau phenomenon was observed in two sprinters and two endurance runners. An upwards curvilinear increase in VO2 was noticed during the last two minutes of exercise in four endurance runners, but not in any of the sprinters. The four endurance runners with this unexpected increase in VO2 had a significantly higher (p < .01) "peak VO2" (mean = 75.3 ml.kg.-1.min.-1) than the rest of the endurance runners (mean = 55.1), and a significantly higher (p < .001) peak VO2 than the sprinters (mean = 46.0). It is concluded that the plateau phenomenon appears in runners during graded cycle ergometry, though rather seldom. It is less clear if the endurance runners showing the upwards curvilinear increase in VO2 possess a better aerobic performance capacity towards the end of progressive exercise. Nevertheless, the linear relationship between VO2 and work load does not appear to be the only one observed in runners during graded exercise.