Applicability of VO2max criteria: discontinuous versus continuous protocols

Area of Science:

• Exercise Physiology
• Sports Science
• Cardiorespiratory Fitness Assessment

Background:

• Maximal oxygen uptake (VO2max) is a key indicator of cardiorespiratory fitness.
• Established protocols exist to elicit VO2max, but their effectiveness in achieving specific criteria varies.
• The Taylor et al. (1955) protocol, in both discontinuous and continuous formats, is used to assess physiological responses.

Purpose of the Study:

• To compare the classic discontinuous Taylor et al. (1955) protocol with a continuous version.
• To evaluate maximal physiological responses during both protocols.
• To assess the quantitative values and achievement rates of VO2max criteria.

Main Methods:

• Ten healthy males (24.1 ± 2.5 yr) performed both discontinuous (DT) and continuous (CT) versions of the Taylor protocol.
• Maximal oxygen uptake (VO2max), ventilation, heart rate (HR), respiratory exchange ratio (RER), and blood lactate were measured.
• VO2max criteria included a VO2 plateau, age-adjusted maximal HR, RER ≥ 1.15, and lactate ≥ 8 mmol·L⁻¹.

Main Results:

• VO2max, ventilation, and HR values were similar between DT and CT (P < 0.05).
• RER and lactate values were significantly higher in the DT compared to the CT (P < 0.05).
• Achievement rates for RER (90% CT, 100% DT) and lactate (90% CT, 100% DT) were higher than for a VO2 plateau (50% CT, 60% DT) or HR criteria (40% CT, 10% DT).

Conclusions:

• A VO2 plateau is not essential for defining VO2max and has limited utility as a primary criterion.
• The achievement of secondary criteria, particularly RER and lactate, strongly indicates that the highest VO2 value obtained is indeed VO2max.
• Continuous protocols may offer advantages in achieving secondary VO2max criteria compared to discontinuous protocols.