Introduction: The traditional maximal oxygen uptake (VO(2max)) protocol has received criticism for being an unnatural form of exercise, lacking ecological validity and producing different VO(2max) responses depending on protocol duration and work rate increments.
Purpose: The purpose of this investigation was to design and test a new VO(2max) protocol allowing subjects to self-pace their work rate while maintaining an incremental test structure.
Methods: 16 untrained subjects completed a self-paced VO(2max) protocol (SPV) and a traditional VO(2max) test in a counter-balanced, crossover design. The SPV used incremental 'clamps' of ratings of perceived exertion (RPE) over 5 × 2-min stages (10-min duration) while allowing subjects to vary their power output (PO) according to the required RPE.
Results: Subjects achieved significantly higher (p < 0.05) VO(2max) values (40 ± 10 ml/kg/min vs 37 ± 8 ml/kg/min) and peak POs (273 ± 58 W vs 238 ± 55 W) in the SPV. Higher VO(2max) values were observed in the SPV even when a plateau (VO(2)-time slope <0.05 l/min) occurred in the traditional test. No differences were found between any other measured physiological variable (minute ventilation, heart rate and respiratory exchange ratio).
Conclusions: As SPV is a closed-loop test (10-min duration) that allows subjects to self-pace their work rate, it disregards the need for experimenters to estimate starting work rates, stage lengths and increments in order to bring about volitional exhaustion in 8-10 min. The observation that the SPV may also elicit higher VO(2max) values than a traditional test warrants further research in this area and its consideration as standard measure to elicit VO(2max).