Test‐retest variability of VO2max using total‐capture indirect calorimetry reveals linear relationship of VO2 and Power

This study aimed to analyze the intra‐individual variation in VO2max of human subjects using total‐capture and free‐flow indirect calorimetry. Twenty‐seven men (27 ± 5 year; VO2max 49‐79 mL•kg−1•min−1) performed two maximal exertion tests (CPETs) on a cycle ergometer, separated by a 7 ± 2 day interval. VO2 and VCO2 were assessed using an indirect calorimeter (Omnical) with total capture of exhalation in a free‐flow airstream. Thirteen subjects performed a third maximal exertion test using a breath‐by‐breath calorimeter (Oxycon Pro). On‐site validation was deemed a requirement. For the Omnical, the mean within‐subject CV for VO2max was 1.2 ± 0.9% (0.0%‐4.4%) and for ergometer workload P max 1.3 ± 1.3% (0%‐4.6%). VO2max values with the Oxycon Pro were significantly lower in comparison with Omnical (P