Jenkins D G, Quigley B M
Department of Human Movement Studies, University of Queensland, St. Lucia, Australia.
Eur J Appl Physiol Occup Physiol. 1990;61(3-4):278-83. doi: 10.1007/BF00357613.
The purposes of this investigation were to determine the validity of critical power (CP) as a measure of the work rate that can be maintained for a very long time without fatigue and to determine whether this corresponded with the maximal lactate steady-state (lass,max). Eight highly trained endurance cyclists (maximal oxygen uptake 74.1 ml.kg-1.min-1, SD 5.3) completed four cycle ergometer tests to exhaustion at pre-determined work rates (360, 425, 480 and 520 W). From these four co-ordinates of work and time to fatigue the regression of work limit on time limit was calculated for each individual (CP). The cyclists were then asked to exercise at their CP for 30 min. If CP could not be maintained, the resistance was reduced minimally to allow the subject to complete the test and maintain a blood lactate plateau. Capillary blood was sampled at 0,5,10,20 and 30 min into exercise for the analysis of lactate. Six of the eight cyclists were unable to maintain CP for 30 min without fatigue. In these subjects, the mean power attained was 6.4% below that estimated by CP. Mean blood lactates (n = 8) reached a steady-state (8.9 mmol.l-1 SD 1.6) during the last 20 min of exercise indicating that CP slightly overestimated lass,max, Individual blood lactates during the last 20 min of exercise were more closely related to the gamma-intercept of the CP curve (r = 0.78, P less than 0.05) than either CP (0.34, NS) or mean power output (r = 0.42, NS).
本研究的目的是确定临界功率（CP）作为衡量在很长一段时间内可维持且不产生疲劳的工作率指标的有效性，并确定其是否与最大乳酸稳态（LASS，max）相对应。八名训练有素的耐力自行车运动员（最大摄氧量74.1 ml·kg⁻¹·min⁻¹，标准差5.3）以预定的工作率（360、425、480和520瓦）完成了四次自行车测力计力竭测试。根据这四个工作和疲劳时间的坐标，计算出每个个体的工作极限对时间极限的回归（CP）。然后要求自行车运动员以其CP进行30分钟的运动。如果无法维持CP，则将阻力最小化降低，以使受试者完成测试并维持血乳酸平台期。在运动开始后的0、5、10、20和30分钟采集毛细血管血样以分析乳酸。八名自行车运动员中有六名无法在不疲劳的情况下维持CP 30分钟。在这些受试者中，达到的平均功率比CP估计值低6.4%。平均血乳酸（n = 8）在运动的最后20分钟内达到稳态（8.9 mmol·l⁻¹，标准差1.6），这表明CP略微高估了LASS，max。在运动的最后20分钟内，个体血乳酸与CP曲线的γ截距的相关性（r = 0.78，P < 0.05）比与CP（0.34，无显著性差异）或平均功率输出（r = 0.42，无显著性差异）更为密切。
