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

Abstract

Figueiredo, PS, Looney, DP, Pryor, JL, Doughty, EM, McClung, HL, Vangala, SV, Santee, WR, Beidleman, BA, and Potter, AW. Verification of maximal oxygen uptake in active military personnel during treadmill running. J Strength Cond Res 36(4): 1053–1058, 2022—It is unclear whether verification tests are required to confirm “true” maximal oxygen uptake (V̇o2max) in modern warfighter populations. Our study investigated the prevalence of V̇o2max 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 V̇o2max 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 V̇o2max attainment during incremental testing by testing for the definitive V̇O2 plateau using a linear least-squares regression approach. Peak oxygen uptake (V̇o2peak) 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 V̇o2peak 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, V̇o2peak was equivalent, apparent from the mean difference in V̇o2peak 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 V̇o2max by performing a modified Astrand treadmill running test. Additional familiarization and verification tests for confirming V̇o2max in healthy active military personnel may be unnecessary.

Verification Phase Confirms V̇O2max in a Hot Environment in Sedentary Untrained Males

“…Observation of a GXT V̇O 2 plateau is an inconsistent phenomenon, and GXT V̇O 2 plateau in a hot environment is no exception. Our low GXT V̇O 2 plateau rate (17%) is consistent with previous studies involving trained cyclists in the heat (25%) (17), children and adolescents (27%) (13), normal weight adults (17%) (4), and overweight adults and adults with obesity (46%) (45) although others have observed higher rates (38,41). The 17% GXT V̇O 2 plateau rate and the low secondary criteria attainment (Table 2) indicate that the verification phase is necessary to confirm a V̇O 2max in a hot condition; otherwise, the use of the term V̇O 2peak is most appropriate.…”

“…The 17% GXT V̇O 2 plateau rate and the low secondary criteria attainment (Table 2) indicate that the verification phase is necessary to confirm a V̇O 2max in a hot condition; otherwise, the use of the term V̇O 2peak is most appropriate. Our 100% verification phase confirmation rate is on par with the 92% confirmation rate shown using the same protocol in trained cyclist in the heat (17) and the vast majority of studies in sedentary (6–8,10–12,20) and military (41) populations in temperate conditions. Aggregate verification phase V̇O 2max values using supramaximal protocols in sedentary populations have spanned nonsignificant, higher, or lower mean differences versus GXT values in temperate conditions ((6,8,10,13,20,45); for a review, see [21]).…”

“…It was essential to determine if T gi and BLa were statistically equivalent before testing to assess whether thermal strain and acidosis carryover from the GXT were present, which may influence verification phase responses (17,26). For V̇O 2max , we defined our upper and lower equivalence boundaries from historical thresholds for V̇O 2 plateau (±2.1 mL·kg −1 ·min −1 ) (40) consistent with others (41), clinically meaningful changes in T gi (±0.55°C) (42), and steady-state metabolic measurements (BLa ±10% of pre-GXT) (43). If our 90% confidence interval (CI) lied within these boundaries, statistical equivalency was achieved.…”