Test–retest reliability of pulmonary oxygen uptake and muscle deoxygenation during moderate- and heavy-intensity cycling in youth elite-cyclists

ABSTRACT

To establish the test–retest reliability of pulmonary oxygen uptake (V̇O₂), muscle deoxygenation (deoxy[haem]) and tissue oxygen saturation (StO₂) kinetics in youth elite-cyclists. From baseline pedalling, 15 youth cyclists completed 6-min step transitions to a moderate- and heavy-intensity work rate separated by 8 min of baseline cycling. The protocol was repeated after 1 h of passive rest. V̇O₂ was measured breath-by-breath alongside deoxy[haem] and StO₂ of the vastus lateralis by near-infrared spectroscopy. Reliability was assessed using 95% limits of agreement (LoA), the typical error (TE) and the intraclass correlation coefficient (ICC). During moderate- and heavy-intensity step cycling, TEs for the amplitude, time delay and time constant ranged between 3.5–21.9% and 3.9–12.1% for V̇O₂ and between 6.6–13.7% and 3.5–10.4% for deoxy[haem], respectively. The 95% confidence interval for estimating the kinetic parameters significantly improved for ensemble-averaged transitions of V̇O₂ (p < 0.01) but not for deoxy[haem]. For StO₂, the TEs for the baseline, end-exercise and the rate of deoxygenation were 1.0–42.5% and 1.1–5.5% during moderate- and heavy-intensity exercise, respectively. The ICC ranged from 0.81 to 0.99 for all measures. Test–retest reliability data provide limits within which changes in V̇O₂, deoxy[haem] and StO₂ kinetics may be interpreted with confidence in youth athletes.

KEYWORDS:

• Oxygen utilization
• oxidative metabolism
• microvascular blood flow
• near-infrared spectroscopy
• reproducibility

Acknowledgments

We gratefully acknowledge the commitment and loyalty of the participants and the logistic support of Mr Roland Wafler, coach of the Austrian Cycling Federation.

Author contributions

AN, BCB and CAW conceived and designed the study and drafted the manuscript. AN, BP, MZ and CR performed the experiments and data analysis. All authors revised and approved the final version of the manuscript.

Disclosure statement

No conflicts of interest, financial or otherwise, are declared by the authors.

Supplementary material

Supplemental data for this article can be accessed online https://doi.org/10.1080/02640414.2020.1792115.