Severe-intensity constant-work-rate cycling indicates that ramp incremental cycling underestimates Vo_2max in a heterogeneous cohort of sedentary individuals

In the absence of a Vo₂-work-rate plateau, debate continues regarding the best way to verify that the peak Vo₂ achieved during incremental exercise (Vo_2peak) is the “true Vo_2max.” Oft-used “secondary criteria” have been questioned in conjunction with the contention that a severe-intensity constant-work-rate “verification bout” should be considered the “gold standard.” The purpose of this study was to compare the Vo_2peak during ramp incremental cycling (RAMP-INC) by a heterogeneous (with respect to body composition and sex) cohort of sedentary individuals with the Vo_2peak during severe-intensity constant-work-rate cycling (CWR) performed after RAMP-INC at the highest work rate achieved. A secondary purpose was to determine the degree to which traditional and newly-proposed age-dependent secondary criteria (RER, HR) identified RAMP-INC which CWR confirmed were characterized by a submaximal Vo_2peak. Thirty-five healthy male (n = 19: 33.4 ± 6.3 yrs) and female (26.8 ± 3.6 yrs) sedentary participants performed RAMP-INC followed by CWR. The Vo_2peak values from the two tests were correlated (r = 0.96; p < 0.01; mean CV = 24%); however, Vo_2peak for CWR was significantly greater (29.6 ± 7.2 v. 28.6 ± 6.8 mL·min^-1·kg^-1; p < 0.01) with a mean bias of 0.98 mL·min^-1·kg^-1 (z = -2.9, p < 0.01). Both traditional and newly-proposed criterion values for RER were achieved during RAMP-INC by 33 of 35 participants (including 21 of 23 who registered a higher Vo_2peak on CWR). The traditional HR criterion value was achieved on only seven tests (three of which were confirmed to be characterized by a submaximal Vo_2peak) while use of less stringent newly-proposed criteria resulted in acceptance of an additional seven tests of which five were confirmed to be submaximal. Severe-intensity CWR to limit of tolerance indicates that RAMP-INC underestimates Vo_2max in sedentary individuals and both traditional and newly-proposed secondary criteria are ineffective for identifying such tests.