EFFECT OF THE SLOW-COMPONENT RISE IN OXYGEN-UPTAKE ON VO2MAX

During constant-rate high-intensity (CRHI) exercise lasting longer tha n 3 min, VO2 has been reported to exceed VO2max measured with a tradit ional graded exercise test (GXT). This could be because VO2max was not achieved on the GXT or because the factors responsible for the slow-c omponent rise in VO2 alter VO2max. The objective of this study was to test the hypothesis that the slow-component rise in VO2 measured durin g CRHI running leads to a total VO2 that exceeds VO2max measured durin g a running GXT. VO2max was determined in eight highly trained individ uals using data collected from five grade-incremented, treadmill-runni ng GXT. Each subject demonstrated a definitive plateau of VO2 as a fun ction of exercise intensity. Three VO2max values based on different ap proaches for representing the VO2max plateau were obtained. Subjects a lso completed two exhaustive CRHI bouts of treadmill running lasting 7 -13 min at speeds estimated from the ACSM equation to elicit an averag e of 99 +/- 5% VO2max. The mean (+/-SD) VO2peak determined during the CRHI runs (4.17 +/- 0.9 I . min(-1)) was not different from or less th an the three VO2max values (4.19-4.32 +/- 0.09 I . min(-1)). We conclu de that in highly trained individuals, the slow-component rise in VO2 during CRHI treadmill running does not lead to a total VO2 that exceed s the VO2max measured during a running graded exercise test.