A “Step-Ramp-Step” Protocol to Identify Running Speed and Power Associated with the Maximal Metabolic Steady State

Abstract

Purpose: A previously established Step-Ramp-Step (SRS) exercise protocol was able to accurately predict the work rate associated with the maximal metabolic steady state (MMSS) in cyclists. The purpose of this study was to determine whether a modified SRS protocol could predict the running speed and power associated with the MMSS. Methods: Fifteen (8 male; 7 female) runners ( VO 2max 54.5 [6.5] mL•kg −1 •min −1 ) were recruited for this investigation composed of four to five visits. In the first visit, runners performed a moderate intensity step (MOD), an incremental exercise test, and a heavy intensity step (HVY), on a motorized treadmill. This SRS protocol was used to predict the running speed and power associated with the MMSS (i.e., the SRS-MMSS), where running power was assessed by a wearable device (Stryd) attached to each runner's shoe. Subsequent visits were used to confirm the maximal lactate steady state (MLSS) as a proxy measure of the MMSS (i.e., the MLSS-MMSS) and to validate the SRS-MMSS speed and power estimates. Results: The estimated SRS-MMSS running speed (7.2 [0.6] mph) was significantly lower than confirmed running speed at MLSS-MMSS (7.5 [0.8] mph; bias = 3.6%, P = 0.005); however, the estimated SRS-MMSS running power (241 [35] W) was not different than the MLSS-MMSS confirmed running power (240 [37] W; bias = −0.6%; P = 0.435). VO 2 at SRS-MMSS (3.22 [0.49] L•min −1 ) was not different than respiratory compensation point (3.26 [0.58] L•min −1 ; P = 0.430). Similarly, VO 2 at MLSS-MMSS (3.30 [0.54] L•min −1 ) was not different than respiratory compensation point ( P = 0.438). Conclusions: The SRS protocol allows MMSS, as measured by MLSS, to be accurately determined using running power (Stryd), but not speed, in a single laboratory visit.

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

“…The SRS protocol has been demonstrated to be a valid and effective tool to predict, from a ramp-incremental test, the PO associated with the GET and the RCP and, more broadly, any PO eliciting at steady state any target VO 2 response during cycling (5,13) and running (19) exercise. However, whether such predictive accuracy would remain true when manipulating either the moderate-intensity step transitions used to com-pute the MRT and the slopes of the ramp test was unknown.…”

“…Because of the dissociation between the VO 2 and PO responses obtained from ramp-incremental compared with constant-load exercise, recent studies have proposed the use of the SRS protocol to correct for this dissociation during cycling (5,12,13) and running (19), so that the corrected ramp-incremental PO at the RCP reflected the PO at MMSS. This principle is based on the consistent findings that the metabolic rate ( VO 2 ) at the RCP coincides with the metabolic rate at the MMSS (5,12,13,25,29).…”

Fractal correlation properties of heart rate variability as a marker of exercise intensity during incremental and constant-speed treadmill running

“…All runners visited the laboratory for an initial maximal incremental exercise test (van Rassel et al, 2022). Twelve of these runners (see Table 1 for description) also performed a series of 4 to 5 constant-speed running bouts to determine the running speed 5% below MLSS, at MLSS, and 5% above MLSS, and to perform a repeat trial at the determined speed associated with MLSS (van Rassel et al, 2023).…”

“…Of relevance to the present study, the maximal exercise test involved a moderate intensity step-transition (MOD; 6 min at 1.9 m·s -1 , 6 min at 2.4 m·s -1 , and 6 min at 1.9 m·s -1 ) followed by incremental treadmill running (an initial speed of 1.9 m·s -1 and increasing by ∼0.2 m·s -1 [i.e., 0.5 mph] per min) until volitional exhaustion (van Rassel et al, 2022). Incremental tests were considered maximal if a plateau in V̇ O 2 was observed (i.e., < 150 mL·min -1 ) despite an increase in running intensity, or if subjects HR was ± 10 bpm of their age-predicted max, RER was greater than 1.15, or [BLa] was at least 8 mmol·L -1 upon test completion.…”

“…The MLSS was identified as the highest treadmill speed where the difference between the [BLa] at 10 and 30 min was ≤ 1 mmol·L -1 and at least 30 min of exercise was performed (Beneke & von Duvillard, 1996). The constant-speed sessions consisted of 5 min of treadmill running at 1.9 m·s -1 , followed by treadmill running at the pre-determined testing speed (van Rassel et al, 2022). Constant-speed sessions were performed until running tests were completed at speeds 5% above, 5% below, and at MLSS.…”