Estimation of the minimal exercise intensity at maximal oxygen uptake

The purpose of the study was to investigate whether modification of a common approach that is used to determine the minimal exercise intensity at which V̇ O2 max is elicited (iV̇ O2 max) improves its accuracy, when compared to an iV̇ O2 max value refined to its lowest value, and a value derived using an approach considered to be the most suitable method of determining iV̇ O2 max. Eleven male cyclists (age 34 ± 8 yrs, body mass 81.6 ± 10.5 kg, height 1.84 ± 0.06 m; V̇ O2 max 4.44 ± 0.48 L∙min-1) performed three maximal incremental tests for the determination of iV̇ O2 max(R). iV̇ O2 max was also determined as: (a) the minimum intensity at which V̇ O2 max was attained (Method 1); the ratio of (V̇ O2 max – V̇ O2 at rest) to (C – V̇ O2 at rest), where C is calculated using the last two stages in the incremental test (Method 2a) and again where C is calculated using all stages in the incremental test (Method 2b). Methods 1, 2a, and 2b produced iV̇ O2 max values that were not significantly different from iV̇ O2 max(R). Method 1 produced an iV̇ O2 max value that was less variable and more similar to iV̇ O2 max(R) (CV = 1.5%; ICC = 0.99) than 2a (CV = 3.0%; ICC = 0.97) and 2b (CV = 4.1%; ICC = 0.95). Methods 1, 2a, and 2b may provide good estimates of iV̇ O2 max(R), but Method 1 appears to be the most robust method, and may be optimal for setting interval training intensities.