Application of V̇o 2 to the Critical Power Model to Derive the Critical V̇o 2

Abstract Succi, PJ, Dinyer, TK, Byrd, MT, Voskuil, CC, and Bergstrom, HC. Application of V̇ o 2 to the critical power model to derive the critical V̇ o 2 . J Strength Cond Res 36(12): 3374–3380, 2022—The purposes of this study were to (a) determine whether the critical power (CP) model could be applied to V̇ o 2 to estimate the critical V̇ o 2 (CV̇ o 2 ) and (b) to compare the CV̇ o 2 with the V̇ o 2 at CP (V̇ o 2 CP), the ventilatory threshold (VT), respiratory compensation point (RCP), and the CV̇ o 2 without the V̇ o 2 slow component (CV̇ o 2 slow). Nine subjects performed a graded exercise test to exhaustion to determine V̇ o 2 peak, VT, and RCP. The subjects performed 4 randomized, constant power output work bouts to exhaustion. The time to exhaustion (T Lim ), the total work (W Lim ), and the total volume of oxygen consumed with (TV̇ o 2 ) and without the slow component (TV̇ o 2 slow) were recorded during each trial. The linear regressions of the TV̇ o 2 vs. T Lim , TV̇ o 2 slow vs. T Lim , and W Lim vs. T Lim relationship were performed to derive the CV̇ o 2 , CV̇ o 2 slow, and CP, respectively. A 1-way repeated-measures analysis of variance ( p ≤ 0.05) with follow-up Sidak-Bonferroni corrected pairwise comparisons indicated that CV̇ o 2 (42.49 ± 3.22 ml·kg −1 ·min −1 ) was greater than VT (30.80 ± 4.66 ml·kg −1 ·min −1 ; p < 0.001), RCP (36.74 ± 4.49 ml·kg −1 ·min −1 ; p = 0.001), V̇ o 2 CP (36.76 ± 4.31 ml·kg −1 ·min −1 ; p < 0.001), and CV̇ o 2 slow (38.26 ± 2.43 ml·kg −1 ·min −1 ; p < 0.001). However, CV̇ o 2 slow was not different than V̇ o 2 CP ( p = 0.140) or RCP ( p = 0.235). Thus, the CP model can be applied to V̇ o 2 to derive the CV̇ o 2 and theoretically is the highest metabolic steady state that can be maintained for an extended period without fatigue. Furthermore, the ability of the CV̇ o 2 to quantify the metabolic cost of exercise and the inefficiency associated with the V̇ o 2 slow component may provide a valuable tool for researchers and coaches to examine endurance exercise.