Faculty of Kinesiology, University of Calgary, Calgary, Alberta, CANADA.
Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, ITALY.
Med Sci Sports Exerc. 2020 Sep;52(9):2011-2019. doi: 10.1249/MSS.0000000000002343.
The oxygen uptake (V[Combining Dot Above]O2) 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.
This 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.
Ten heathy volunteers (5 women; age: 30 ± 7 yr; V[Combining Dot Above]O2max: 54 ± 6 mL·kg·min) performed in the following series: a 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 V[Combining Dot Above]O2 at lactate threshold (LT) and RCP. The PO at LT was determined by the linear regression of the V[Combining Dot Above]O2 versus PO relationship after adjusting ramp data by the difference between the ramp PO at the steady-state V[Combining Dot Above]O2 from MOD and 100 W. Linear regression between the V[Combining Dot Above]O2-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.
All participants completed 30 min of constant-power exercise at the SRS-estimated RCP achieving steady-state V[Combining Dot Above]O2 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 V[Combining Dot Above]O2.
In 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.
呼吸补偿点（RCP）处的耗氧量（V[Combining Dot Above]O2）与最大代谢稳态密切相关。然而，当代递增 ramp 运动方案无法确定 RCP 处的功率输出（PO）。
本研究旨在测试“阶梯 ramp 阶梯”（SRS）自行车方案估算 RCP 处 PO 的功效，并验证 RCP 作为最大代谢稳态替代物的有效性。
10 名健康志愿者（5 名女性；年龄：30 ± 7 岁；V[Combining Dot Above]O2max：54 ± 6 mL·kg·min）进行以下系列测试：适度向 100 W（MOD）过渡，然后递增 ramp（30 W·min），并在 30 分钟恢复期后，过渡至接近 50%POpeak（HVY）。ramp 期间的通气和气体交换数据用于确定乳酸阈（LT）和 RCP 处的 V[Combining Dot Above]O2。通过从 MOD 和 100 W 的 ramp PO 之间的差值调整 ramp 数据，对 V[Combining Dot Above]O2 与 PO 关系的线性回归确定 LT 处的 PO。LT 和 HVY 相关的 V[Combining Dot Above]O2-PO 值的线性回归通过外推提供了 RCP 处的 PO。参与者随后在 SRS 估算的 RCP 和高于此 PO5%的位置进行 30 分钟恒功率测试。
所有参与者均在 SRS 估算的 RCP 处完成 30 分钟恒功率运动，达到 3176 ± 595 mL·min 的稳态 V[Combining Dot Above]O2，与 ramp 确定的 RCP（3095 ± 570 mL·min）无差异（P = 0.80），且参与者内高度一致（偏差=-26 mL·min，r = 0.97，变异系数=2.3%±2.8%）。在 SRS 估算的 RCP 之上 5%的位置，有 4 名参与者无法完成 30 分钟，且所有人（除 2 人外）均出现血乳酸和 V[Combining Dot Above]O2 的非稳态反应。
在以自身最佳踏频骑行的健康个体中，SRS 方案和 RCP 能够准确预测与最大代谢稳态相关的 PO。
