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.

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Context: Following concussion, a multi-faceted assessment is recommended, including tests of physical exertion. The current gold standard for exercise testing following concussion is the Buffalo Concussion Treadmill Test (BCTT); however, there is a lack of validated tests that utilize alternative exercise modalities. Objective: To assess the feasibility and concurrent validity of a novel cycling test of exertion compared to the BCTT. Design: Crossover Study Setting: University Sport-Medicine Clinic Patients: Twenty adults (aged 18–60 years) diagnosed with a Sport-Related Concussion Intervention: Participants completed the BCTT and a cycling test of exertion in a random order, approximately 48 hours apart. Main Outcome Measures: The primary outcome of interest was maximum heart rate [HRmax; beats per minute (bpm)]. Secondary outcomes of interest included whether the participant reached volitional fatigue (yes/no), symptom responsible for test cessation (Post Concussion Symptom Scale), and Symptom Severity on a Visual Scale (/10). Results: Of the 20 participants, 19 (10 male, 9 female) completed both tests. One participant did not return for the second test and was excluded from the analysis. No adverse events were reported. The median HRmax for the BCTT [171 bpm; (IQR: 139–184bpm)] was not significantly different than the median HRmax for the Cycle [173 bpm; (IQR: 160–182)] (z=–0.63, p=0.53). For both tests, the three most frequently reported symptoms responsible for test cessation were Headache, Dizziness, and Pressure in the head. Of interest, the majority of participants (64%) reported a different symptom responsible for test cessation on each test. Conclusion: The novel cycling test of exertion achieved similar HRmax and test duration and may be a suitable alternative to the BCTT. Future research to understand the physiological reason for the heterogeneity in symptoms responsible for test cessation is warranted.