Application of V o ₂to the Critical Power Model to Derive the Critical V o ₂

Succi, PJ, Dinyer, TK, Byrd, MT, Voskuil, CC, and Bergstrom, HC. Application of Vo2 to the critical power model to derive the critical Vo2. 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 Vo2 to estimate the critical Vo2 (CVo2) and (b) to compare the CVo2 with the Vo2 at CP (Vo2CP), the ventilatory threshold (VT), respiratory compensation point (RCP), and the CVo2 without the Vo2 slow component (CVo2slow). Nine subjects performed a graded exercise test to exhaustion to determine Vo2peak, VT, and RCP. The subjects performed 4 randomized, constant power output work bouts to exhaustion. The time to exhaustion (TLim), the total work (WLim), and the total volume of oxygen consumed with (TVo2) and without the slow component (TVo2slow) were recorded during each trial. The linear regressions of the TVo2 vs. TLim, TVo2slow vs. TLim, and WLim vs. TLim relationship were performed to derive the CVo2, CVo2slow, and CP, respectively. A 1-way repeated-measures analysis of variance (p ≤ 0.05) with follow-up Sidak-Bonferroni corrected pairwise comparisons indicated that CVo2 (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), Vo2CP (36.76 ± 4.31 ml·kg-1·min-1; p < 0.001), and CVo2slow (38.26 ± 2.43 ml·kg-1·min-1; p < 0.001). However, CVo2slow was not different than Vo2CP (p = 0.140) or RCP (p = 0.235). Thus, the CP model can be applied to Vo2 to derive the CVo2 and theoretically is the highest metabolic steady state that can be maintained for an extended period without fatigue. Furthermore, the ability of the CVo2 to quantify the metabolic cost of exercise and the inefficiency associated with the Vo2 slow component may provide a valuable tool for researchers and coaches to examine endurance exercise.