ORIGINAL RESEARCH article
Front. Physiol.
Sec. Exercise Physiology
Volume 16 - 2025 | doi: 10.3389/fphys.2025.1547662
This article is part of the Research TopicExercise and the Oxygen Cascade: From the Lungs to the MuscleView all articles
V ̇O2 Linear Onset Kinetics Spanning Steady and Non-Steady State Exercise
Provisionally accepted
- 1Queensland University of Technology, Brisbane, Australia
- 2Queensland Academy of Sport, Sunnybank, Queensland, Australia
- 3Faculty of Medicine in Pilsen, Charles University, Plzen, Plzen Region, Czechia
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
The traditional method for quantifying the kinetics of the increase in the body's consumption of oxygen (V ̇O2) during exercise transitions to steady state involves application of a monoexponential function. Anomalies exist to question the validity of this method, as they show the initial (~ 1 min) of this V ̇O2 response is linear. Fourteen highly endurance trained subjects (12 males, 2 females) completed a ramp incremental cycling protocol, as well as 8 different constant load trials at 43 to 148 % of their critical power (CP). For the initial five exercise bouts, the linear fit of the initial segment was significantly more accurate (lower standard error of estimates; SE) compared to the mono-exponential fit (p<0.001). There were two different systematic profiles of the linear onset (LO) V ̇O2 slope from different bouts of increasing exercise intensities; 1) a sustained increase (increased kinetics) (n = 7), and 2) a plateau or decrease (impaired kinetics) (n = 7). Both sub-groups were similar in all measures of cardio-respiratory and muscular endurance. The LO V ̇O2 kinetics method is superior to the traditional approach as it was a more valid representation of the initial V ̇O2 response, can be applied to both steady and non-steady state exercise intensities, requires less than 2 min of exercise, but across multiple bouts, and identifies more complex physiology than the monoexponential method. Added research is needed to discern the most valid methods to measure LO V ̇O2 kinetics, and to learn more about its physiological determinants compared to the traditional mono-exponential method.
Keywords: Cycling, endurance exercise, training, Plateau, critical power, Oxygen Consumption
Received: 18 Dec 2024; Accepted: 26 Jun 2025.
Copyright: © 2025 Robergs, O'Malley, Dewilde, D'Auria and Krouzecky. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Robert Andrew Robergs, Queensland University of Technology, Brisbane, Australia
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.