A modified step-ramp-step protocol to prescribe constant-speed exercise in treadmill running

Purpose This study investigated whether a running-adapted version of the cycling-based "step-ramp-step" (SRS) protocol would improve prediction of (V) over dotO(2) in treadmill exercise compared to the traditional prescriptive approach. Methods Fourteen healthy individuals (6 females; 25 +/- 6 years; 66.1 +/- 12.7 kg) performed a treadmill-based SRS protocol including a ramp-incremental test to task failure followed by two constant-speed bouts within the moderate-(MODstep-below estimated lactate threshold; theta(LT)), and heavy-intensity domains (HVYstep-between theta(LT) and respiratory compensation point; RCP). Using the uncorrected (V) over dotO(2)-to-speed relationship from the ramp exercise, three constant-speed bouts were performed at 40-50% between: baseline and theta(LT) (CSEMOD); theta(LT) and RCP (CSEHVY); and RCP and peak (CSESEV). For CSEMOD, CSEHVY, and CSESEV measured end-exercise (V) over dotO(2) was compared to predicted (V) over dotO(2) based on the: (i) "SRS-corrected" (V) over dotO(2)-to-speed relationship (where MODstep and HVYstep were used to adjust the (V) over dotO(2) relative to speed); and (ii) linear "uncorrected" data. Results Average treadmill speeds for CSEMOD and CSEHVY were 7.8 +/- 0.8 and 11.0 +/- 1.4 km center dot h(-1), respectively, eliciting end-exercise (V) over dotO(2) of 1979 +/- 390 and 2574 +/- 540 mL center dot min(-1). End-exercise (V) over dotO(2) values were not different compared to SRS-predicted (V) over dotO(2) at CSEMOD (mean difference: 5 +/- 166 mL center dot min(-1); p = 0.912) and CSEHVY (20 +/- 128 mL center dot min(-1); p = 0.568). The linear "uncorrected" estimates were not different for CSEMOD (- 91 +/- 172 mL center dot min(-1); p = 0.068) but lower for CSEHVY (- 195 +/- 146 mL center dot min(-1); p < 0.001). For CSESEV (running speed: 13.8 +/- 1.7 km center dot h(-1)), the end-exercise (V) over dotO(2) was not different from peak (V) over dotO(2) achieved during the ramp (3027 +/- 682 vs. 2979 +/- 655 mL center dot min(-1); p = 0.231). Conclusion In healthy individuals, the SRS protocol more accurately predicts speeds for a target (V) over dotO(2) compared to traditional approaches.