Leo Jeffrey A, Sabapathy Surendran, Simmonds Michael J, Cross Troy J
1Menzies Health Institute Queensland, Griffith University, Gold Coast, QLD, AUSTRALIA; and 2Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN.
Med Sci Sports Exerc. 2017 Jul;49(7):1452-1460. doi: 10.1249/MSS.0000000000001226.
It is unclear whether the respiratory compensation point (RCP) may be used as a valid surrogate for critical power (CP). Accordingly, we sought to determine the measurement agreement between the CP and the RCP obtained during incremental cycling of varying ramp slopes.
Eleven recreationally active men completed three separate ramp-incremental cycling protocols, where the work rate increment was slow (SR, 15 W·min), medium (MR, 30 W·min), or fast (FR, 45 W·min). The RCP was obtained using the ventilatory equivalent for CO2 output method. The CP was determined via Morton's model for ramp-incremental exercise. The assumption that the RCP and the CP occur at equivalent external work rates was assessed by one-way repeated-measures ANOVA and by evaluating the concordance correlation coefficient (CCC) and typical error (root-mean-square error [RMSE]) for each ramp protocol, separately.
The external work rate corresponding to the RCP increased with increases in the ramp-incremental slope (P < 0.05). The RCP values in MR (268 ± 37 W) and FR (292 ± 41 W), but not SR (243 ± 35 W), were different (P < 0.05) from CP (247 ± 43 W). The degree to which the relationship between the CP and the RCP approximated the line of identity was relatively poor for SR (CCC = 0.73 and RMSE = 28 W), MR (CCC = 0.63 and RMSE = 36 W), and FR (CCC = 0.42 and RMSE = 55 W).
Our data confirm that the external work rate associated with the RCP is labile and that these power outputs display poor measurement agreement with the CP. Taken together, these findings indicate that the RCP does not provide an accurate estimation of CP.
尚不清楚呼吸补偿点（RCP）是否可作为临界功率（CP）的有效替代指标。因此，我们试图确定在不同坡度递增的骑行运动中获得的CP和RCP之间的测量一致性。
11名有休闲运动习惯的男性完成了三项独立的坡度递增骑行方案，其中工作负荷递增速度分别为慢（SR，15 W·min）、中（MR，30 W·min）或快（FR，45 W·min）。采用二氧化碳呼出通气当量法获得RCP。通过莫顿模型确定递增运动的CP。通过单向重复测量方差分析以及分别评估每个坡度方案的一致性相关系数（CCC）和典型误差（均方根误差[RMSE]），来评估RCP和CP在相同外部工作负荷时出现的假设。
与RCP相对应的外部工作负荷随坡度递增斜率的增加而增加（P<0.05）。MR组（268±37 W）和FR组（292±41 W）的RCP值与CP（247±43 W）不同（P<0.05），但SR组（243±35 W）并非如此。SR组（CCC = 0.73，RMSE = 28 W）、MR组（CCC = 0.63，RMSE = 36 W）和FR组（CCC = 0.42，RMSE = 55 W）中，CP与RCP之间关系接近恒等线的程度相对较差。
我们的数据证实，与RCP相关的外部工作负荷不稳定，且这些功率输出与CP的测量一致性较差。综上所述，这些结果表明RCP不能准确估算CP。
