Verification of Maximal Oxygen Uptake in Active Military Personnel during Treadmill Running

It is unclear whether verification tests are required to confirm "true"maximal oxygen uptake (Vo2max) in modern warfighter populations. Our study investigated the prevalence of Vo2max attainment in U.S. Army soldiers performing a traditional incremental running test. In addition, we examined the utility of supramaximal verification testing as well as repeated trials for familiarization for accurate Vo2max assessment. Sixteen U.S. Army soldiers (1 woman, 15 men; age, 21 ± 2 years; height, 1.73 ± 0.06 m; body mass, 71.6 ± 10.1 kg) completed 2 laboratory visits, each with an incremental running test (modified Astrand protocol) and a verification test (110% maximal incremental test speed) on a motorized treadmill. We evaluated Vo2max attainment during incremental testing by testing for the definitive VO2 plateau using a linear least-squares regression approach. Peak oxygen uptake (Vo2peak) was considered statistically equivalent between tests if the 90% confidence interval around the mean difference was within ±2.1 ml·kg-1·min-1. Oxygen uptake plateaus were identified in 14 of 16 volunteers for visit 1 (87.5%) and all 16 volunteers for visit 2 (100%). Peak oxygen uptake was not statistically equivalent, apparent from the mean difference in Vo2peak measures between the incremental test and verification test on visit 1 (2.3 ml·kg-1·min-1, [1.3-3.2]) or visit 2 (1.1 ml·kg-1·min-1 [0.2-2.1]). Interestingly, Vo2peak was equivalent, apparent from the mean difference in Vo2peak measures between visits for the incremental tests (0.0 ml·kg-1·min-1 [-0.8 to 0.9]) but not the verification tests (-1.2 ml·kg-1·min-1 [-2.2 to-0.2]). Modern U.S. Army soldiers can attain Vo2max by performing a modified Astrand treadmill running test. Additional familiarization and verification tests for confirming Vo2max in healthy active military personnel may be unnecessary.