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  • A “Step–Ramp–Step” Protocol...
    IANNETTA, DANILO; INGLIS, ERIN CALAINE; POGLIAGHI, SILVIA; MURIAS, JUAN M; KEIR, DANIEL A

    Medicine and science in sports and exercise, 2020-September, Volume: 52, Issue: 9
    Journal Article

    The oxygen uptake (VCombining Dot AboveO2) at the respiratory compensation point (RCP) closely identifies with the maximal metabolic steady state. However, the power output (PO) at RCP cannot be determined from contemporary ramp-incremental exercise protocols. PURPOSEThis study aimed to test the efficacy of a “step–ramp–step” (SRS) cycling protocol for estimating the PO at RCP and the validity of RCP as a maximal metabolic steady-state surrogate. METHODSTen heathy volunteers (5 women; age30 ± 7 yr; VCombining Dot AboveO2max54 ± 6 mL·kg·min) performed in the following seriesa moderate step transition to 100 W (MOD), ramp (30 W·min), and after 30 min of recovery, step transition to ~50% POpeak (HVY). Ventilatory and gas exchange data from the ramp were used to identify the VCombining Dot AboveO2 at lactate threshold (LT) and RCP. The PO at LT was determined by the linear regression of the VCombining Dot AboveO2 versus PO relationship after adjusting ramp data by the difference between the ramp PO at the steady-state VCombining Dot AboveO2 from MOD and 100 W. Linear regression between the VCombining Dot AboveO2–PO values associated with LT and HVY provided, by extrapolation, the PO at RCP. Participants then performed 30-min constant-power tests at the SRS-estimated RCP and 5% above this PO. RESULTSAll participants completed 30 min of constant-power exercise at the SRS-estimated RCP achieving steady-state VCombining Dot AboveO2 of 3176 ± 595 mL·min that was not different (P = 0.80) from the ramp-identified RCP (3095 ± 570 mL·min) and highly consistent within participants (bias = −26 mL·min, r = 0.97, coefficient of variation = 2.3% ± 2.8%). At 5% above the SRS-estimated RCP, four participants could not complete 30 min and all, but two exhibited non–steady-state responses in blood lactate and VCombining Dot AboveO2. CONCLUSIONSIn healthy individuals cycling at their preferred cadence, the SRS protocol and the RCP are capable of accurately predicting the PO associated with maximal metabolic steady state.