The exercise intensity at maximal oxygen uptake (i⩒O_2max): Methodological issues and repeatability

Abstract

The minimum exercise intensity that elicits ⩒O_2max (i⩒O_2max) is an important variable associated with endurance exercise performance. i⩒O_2max is usually determined during a maximal incremental exercise test; however, the magnitude and duration of the increments used influence the i⩒O_2max value produced by a given test. The aims of this study were twofold. The first was to investigate whether the i⩒O_2max value produced by a single cycle ergometer test (i⩒O_2max(S)) was repeatable. The second was to determine if i⩒O_2max(S) represents the minimum intensity at which ⩒O_2max is elicited when compared to a refined i⩒O_2max value (i⩒O_2max(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; VO_2max 4.27 ± 0.62 L min⁻¹) performed four maximal incremental tests for the determination of i⩒O_2max(S) and i⩒O_2max(R) (3 min stages; 20 W increments). Trials 1 and 2 were identical and used for assessing the repeatability of i⩒O_2max(S), trials 3 and 4 began at different intensities and were used to determine i⩒O_2max(R). i⩒O_2max(S) showed good test–retest repeatability for i⩒O_2max (CV = 4.1%; ICC = 0.93), VO_2max (CV = 6.3%; ICC = 0.88) and test duration (CV = 6.7%; ICC = 0.89). There was no significant difference between i⩒O_2max(S) and i⩒O_2max(R) (303 ± 40 W vs. 301 ± 42 W) (P < .05). The present results suggest that i⩒O_2max determined directly during a maximal incremental test is repeatable and provides a very good estimate of the minimum exercise intensity that elicits ⩒O_2max.

Keywords:

• Cycle ergometry
• exercise intensity
• maximal oxygen uptake
• repeatability

Acknowledgements

The authors would like to thank all the athletes who participated in this investigation for their enthusiasm and dedication to the project.

Disclosure statement

No potential conflict of interest was reported by the authors.