Evaluation of the "Step-Ramp-Step" Protocol: Accurate Aerobic Exercise Prescription with Different Steps and Ramp Slopes

The step-ramp-step (SRS) can assign constant-load exercise intensities from a ramp-incremental test. Its precision using different moderate-intensity (MOD) steps or ramp slopes has yet to be evaluated. Purpose To assess whether: i) a lower amplitude constant-load MOD is appropriate to determine the mean response time (MRT); ii) the method accurately corrects the dissociation in the VO2-PO relationship during ramp compared with constant-load exercise when using different ramp slopes. Methods Eighteen participants (7 females) performed three SRS tests including: i) step-transitions into MOD from 20 to 50 W (MOD50) and 80 W (MOD80); and ii) slopes of 15, 30, and 45 W·min-1. The VO2 and PO at the gas exchange threshold (GET) and the corrected respiratory compensation point (RCPCORR) were determined. Two to three 30-min constant-load trials evaluated the VO2 and PO at the maximal metabolic steady state (MMSS). Results There were no differences in VO2 at GET (1.97 ± 0.36, 1.99 ± 0.36, 1.95 ± 0.30 L·min-1), and RCP (2.81 ± 0.57, 2.86 ± 0.59, 2.84 ± 0.59) between 15, 30, and 45 W·min-1 ramps, respectively (P > 0.05). The MRT in seconds was not affected by the amplitude of the MOD or the slope of the ramp (range 19 ± 10 s to 23 ± 20 s; P > 0.05). The mean PO at GET was not significantly affected by the amplitude of the MOD or the slope of the ramp (range 130 ± 30 W to 137 ± 30 W; P > 0.05). The PO at RCPCORR was similar for all conditions ((range 186 ± 43 W to 193 ± 47 W; P > 0.05). Conclusions The SRS protocol accounts for the VO2 MRT when using smaller amplitude steps, and for the VO2 slow component when using different ramp slopes, allowing for accurate partitioning of the exercise intensity domains in a single test.