Confirmation of Treadmill VO2max in Sprinters and Long Distance Runners

Abstract

A plateau in oxygen uptake (VO2) despite an increase in work rate is often not observed during continuous incremental exercise tests. Indirect criteria including respiratory exchange ratio (R > 1.10) and blood lactate concentration ([La-] > 8.0 mM) are frequently used to confirm maximal oxygen uptake (VO2max) in the absence of a plateau in VO2. Recently, a test to directly confirm VO2peak was developed for healthy males performing cycle ergometry (J Appl Physiol 100: 764-770, 2006). PURPOSE: The purpose of this investigation was to determine whether long distance runners and sprinters routinely display a VO2 plateau during continuous incremental treadmill tests, and if not, whether the highest VO2 observed was in fact VO2max. METHODS: Nine male long distance runners (age 21 ± 1 yrs, VO2max 71.0 ± 2.8 mL·kg−1·min−1) and six male sprinters (age 26 ± 3 yrs, VO2max 55.9 ± 5.8 mL·kg−1·min−1) ran to volitional exhaustion at a constant treadmill speed previously determined to elicit 4 mM blood [La-]. This continuous incremental test consisted of two-minute stages with 2% grade increments. A VO2 plateau was defined as less than half the expected increase in VO2 between the last two completed stages. Following a 15 minute recovery period, subjects performed a constant work rate test to exhaustion at a steeper grade. Data were analyzed by paired-samples t-test. RESULTS: None of the long distance runners and one of the sprinters achieved a plateau on the continuous incremental test. However, by combining the data from the continuous incremental test and the constant work rate test, all subjects exhibited a discontinuous plateau in VO2. Peak VO2 on the continuous incremental test for the long distance runners (70.6 ± 2.8 mL·kg−1·min−1) was not significantly different (P = 0.12) from peak VO2 on the constant work rate test (69.2 ± 2.5 mL·kg−1·min−1). Peak VO2 on the continuous incremental test for the sprinters (55.6 ± 5.9 mL·kg−1·min−1) was not significantly different (P = 0.09) from peak VO2 on the constant work rate test (53.4 ± 5.0 mL·kg−1·min−1). CONCLUSIONS: Trained competitive sprinters and long distance runners do not routinely exhibit a plateau at VO2max during continuous incremental treadmill tests. Peak VO2 on a continuous incremental treadmill test can be directly confirmed as VO2max by performing an additional higher work rate test following a short rest.