title: The exercise intensity at maximal oxygen uptake (i⩒O2max): Methodological issues and repeatability.
abstract: The minimum exercise intensity that elicits ⩒O2max (i⩒O2max) is an important variable associated with endurance exercise performance. i⩒O2max is usually determined during a maximal incremental exercise test; however, the magnitude and duration of the increments used influence the i⩒O2max value produced by a given test. The aims of this study were twofold. The first was to investigate whether the i⩒O2max value produced by a single cycle ergometer test (i⩒O2max(S)) was repeatable. The second was to determine if i⩒O2max(S) represents the minimum intensity at which ⩒O2max is elicited when compared to a refined i⩒O2max value (i⩒O2max(R)) derived from repeated tests. Seventeen male cyclists (age 33.9 ± 7.7 years, body mass 80.9 ± 10.2 kg, height 1.82 ± 0.05 m; VO2max 4.27 ± 0.62 L min(-1)) performed four maximal incremental tests for the determination of i⩒O2max(S) and i⩒O2max(R) (3 min stages; 20 W increments). Trials 1 and 2 were identical and used for assessing the repeatability of i⩒O2max(S), trials 3 and 4 began at different intensities and were used to determine i⩒O2max(R). i⩒O2max(S) showed good test-retest repeatability for i⩒O2max (CV = 4.1%; ICC = 0.93), VO2max (CV = 6.3%; ICC = 0.88) and test duration (CV = 6.7%; ICC = 0.89). There was no significant difference between i⩒O2max(S) and i⩒O2max(R) (303 ± 40 W vs. 301 ± 42 W) (P < .05). The present results suggest that i⩒O2max determined directly during a maximal incremental test is repeatable and provides a very good estimate of the minimum exercise intensity that elicits ⩒O2max.
authors.affiliation: a People and Organisational Development , De Montfort University , Leicester , UK.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Merry
authors.affiliation: b School of Sport, Health and Applied Science , St Mary's University , Twickenham , UK.
authors.forename: Mark
authors.initials: M
authors.lastname: Glaister
authors.affiliation: c School of Life Sciences , Northumbria University , Newcastle upon Tyne , UK.|d Water Research Group, School of Environmental Sciences and Development , Northwest University , Potchefstroom , South Africa.
authors.forename: Glyn
authors.initials: G
authors.lastname: Howatson
authors.affiliation: e GlaxoSmithKline Human Performance Laboratory , Brentford , UK.
authors.forename: Ken
authors.initials: K
authors.lastname: Van Someren
mesh_terms: D000328:Adult; D054874:Athletic Performance / Q000502:physiology*; D001642:Bicycling / Q000502:physiology; D016552:Ergometry / Q000379:methods / Q000592:standards*; D015444:Exercise / Q000502:physiology; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D015203:Reproducibility of Results
keywords: Cycle ergometry; exercise intensity; maximal oxygen uptake; repeatability