Validity and test-retest reliability of the VO2 Master metabolic analyser: A laboratory and artistic gymnastics-specific evaluation

Purpose: This study assessed validity and reliability of the mobile metabolic analyser VO2 Master under laboratory and gymnastics-specific conditions for assessment of oxygen uptake (VO2) and minute ventilation (VE). Methods: For validity testing six metabolic rates (from 1.0 to 4 L·min-1) were reproduced by a metabolic simulator (VacuMed) and VE and VO2 were measured by two different VO2 Master devices (serial number 3209 and 3212). To evaluated test-retest reliability nine German junior national squad gymnasts (age 16.4 ± 1.0 years; height 168.2 cm; weight 59.4 kg) performed a circle test and nine (seven male and 2 female) athletic adults (age 29.7 ± 4.9 years; height 177.8 ± 7.4 cm; weight 71.3 ± 6.6 kg) performed a floor-specific test. Validity was assessed by Deming regression analysis, Bland-Altman plots, concordance correlation coefficient (CCC) and mean percentage error (MPE), for VE and VO2. Test-retest reliability was analysed using standard error of measurement (% SEM), the intra-class correlation coefficient (ICC2,1) and Bland-Altman plots for VO2mean, VO2peak, O2 deficit and O2 integral. Results: The VO2 Masters shows a MPE of 10.44 ±1.48%. and 7.56 ±1.97 % (3212) and 6.73 ±1.93 % and 7.56 ±1.45 % for VO2 and VE. The CCCs of 0.97 and 0.99 for VO2 and 0.98 for VE indicate a substantial to almost perfect agreement between VacuMed and VO2 Masters. In CT, VO2mean, VO2peak, O2 deficit and O2 integral showed ICCs between 0.74 and 0.95. and % SEM of ≤10% and ≤5%. In FST, VO2mean, VO2peak, O2 deficit and O2 integral showed ICCs between 0.76 and 0.94 and values of ≤10% and ≤5% for % SEM. Conclusions: The VO2 Master is a practicable, reliable and valid metabolic analyser to measure VO2 and VE during short term exercises like artistic gymnastics routines.