Efficacy of constant load verification testing to confirm VO₂ max attainment

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiorespiratory Fitness Assessment

Background:

• Maximal oxygen uptake (VO2 max) measurement has a long history, but the precise attainment of 'true' VO2 max is not well-defined.
• Current criteria, including the VO2 plateau and secondary measures, have limitations in frequency and validity for confirming VO2 max.
• Verification tests (VER) are used to validate VO2 max from incremental tests (INC), but existing research is limited.

Purpose of the Study:

• To investigate the efficacy of the verification test (VER) in confirming 'true' maximal oxygen uptake (VO2 max).
• To analyze differences in VO2 max estimates between incremental (INC) and verification (VER) protocols.
• To explore the influence of participant fitness level on the accuracy of VO2 max verification.

Main Methods:

• Analyzed data from 109 participants undergoing both incremental (INC) and verification (VER) tests.
• VER was conducted at 105% or 110% of peak power output (PPO) following the INC test.
• Calculated differences in VO2 max, intraclass correlation coefficient (ICC), standard error of the mean (SEM), and minimum difference (MD).

Main Results:

• VO2 max was significantly higher (2%, P<0.05) during the incremental test (INC) compared to the verification test (VER).
• High correlation (ICC=0.99) was observed between protocols, with low SEM and MD, suggesting good reliability.
• However, 11% of participants showed a higher VO2 max in the verification phase, indicating failure to confirm 'true' VO2 max.

Conclusions:

• The verification test (VER) does not reliably confirm 'true' maximal oxygen uptake (VO2 max) in all individuals.
• Lower fitness levels were associated with a greater discrepancy in VO2 max values between INC and VER protocols.
• Further research is needed to refine methods for accurately determining 'true' VO2 max, especially across diverse fitness populations.