A test to establish maximum O2 uptake despite no plateau in the O2 uptake response to ramp incremental exercise

The O-2 uptake (Vo(2)) response to ramp incremental (RI) exercise does not consistently demonstrate plateau-like behavior at the limit of tolerance, and hence the requirements for a maximum Vo(2) commonly are not met, despite apparent maximum effort. We sought to determine whether an appended step exercise (SE) test at a work rate greater than that achieved in a preceding ramp test would establish the plateau criterion. Seven healthy male adults performed RI cycle ergometry (20 W/min) to the limit of tolerance, followed by 5-min recovery (20 W) and then an SE test at 105% (RISE-105) of the final work rate (WRpeak) achieved during RI. Five of these subjects also performed an RI test followed by SE at 95% WRpeak (RISE-95). Vo(2) was measured breath by breath using a turbine and mass spectrometer. The average of the final 15 s of RI or SE was used to establish respective Vo(2) peaks. When Vo(2) peak was approached, a constant Vo(2) value (e. g., a plateau) was not discernable during any RI or SE component of the tests. Although the WRpeak [mean (SD)] was higher during the SE portion [359 W (SD 31)] than during the RI portion [341 W ( SD 29)] of the RISE-105, the peak V. O2 was not different [SE, 4.30 1/min ( SD 0.51); RI, 4.33 1/min ( SD 0.52); P = 0.49; n = 7]. Similarly, in the RISE-95 test, WRpeak was 310 W (SD 31) for the SE portion and 326 W (SD 32) for the RI portion, yet the peak V. O2 values were not different [SE, 4.12 1/min (SD 0.53); RI, 4.11 1/min (SD 0.48); P = 0.78; n = 5]. The lack of notable difference between the Vo(2) peaks established at different WRpeak values in our RISE protocols provides the plateau criterion for verification of maximum Vo(2) in a single test session, even when the data response profiles do not themselves evidence a plateau.