The 3-min all-out exercise test (3 MT) is purported to estimate critical power (CP) and anaerobic work capacity (W′) and serve as an exercise mode for measuring maximum oxygen uptake (V˙O2max). Reliability analysis of the 3 MT has been confined to CP, not W′, and verification of “true” V˙O2max was exclusive to a graded exercise test (GXT).
Purpose: We conducted a reliability analysis of the 3 MT and compared V˙O2max values from the 3 MT with a GXT and an exhaustive square-wave verification bout.
Methods: Upon completion of a custom GXT and square-wave verification protocol, 11 subjects of various aerobic powers completed two 3 MTs (separate visits). CP, W′, average power during 150 s from the 3 MT, and V˙O2max values were assessed using typical error (TE), coefficient of variation (CV), and intraclass correlation (α).
Results: CP (W) (trial 1 = 206 ± 47, trial 2 = 206 ± 42) did not differ between 3 MT trials (P = 0.37) and was reliable (TE = 15 W, CV = 7%, α = 0.93). W′ was less reliable (TE = 2864 J, CV = 28%, α = 0.76) but did not alter power–duration estimates from the two 3 MTs (P > 0.05). Variability for V˙O2max (TE (mL·kg−1·min−1)) between the GXT and the verification bout (1.16) was more consistent than the first (2.03) or second (2.69) 3 MT.
Conclusions: The 3 MT yields reliable estimates of CP and consistent estimates of the power–duration relationship. Power for 150 s, in comparison with W′, is a more reliable metric of short-term power performance. The square-wave protocol is recommended over the 3 MT for verifying true V˙O2max.