Ozkaya Ozgur, As Hakan, Peker Arda, Burnley Mark, Jones Andrew M
Institution of Health Sciences, Ege University, Bornova, Izmir, TURKIYE.
Faculty of Sports Sciences, Ege University, Bornova, Izmir, TURKIYE.
Med Sci Sports Exerc. 2025 Jan 1;57(1):217-226. doi: 10.1249/MSS.0000000000003548. Epub 2024 Aug 26.
This study aimed to develop a new method that more closely represents the heavy to severe exercise domain boundary by evaluating the rates of blood lactate accumulation during the constant power output exercise bouts that are used in the assessment of the maximal lactate steady state (MLSS).
Eight well-trained male cyclists completed five exercise tests of up to 30 min for the determination of the traditional MLSS (MLSS TRAD ) and a further four maximal tests for the determination of critical power (CP). The rates of change of blood [lactate] between 10 min and the end of exercise in the MLSS tests were plotted against the corresponding power outputs, and a two-segment linear regression model was used to identify individualized break points in lactate accumulation versus power output (modified MLSS [MLSS MOD ]).
MLSS MOD was significantly higher than MLSS TRAD (297 ± 41 vs 278 ± 41 W, P < 0.001) but was not significantly different from CP (297 ± 41 W, P > 0.05); MLSS MOD and CP were closely aligned ( r = 0.97, bias = -0.52 W, SEE = 10 W, limits of agreement = -20 to 19 W). The rates of change of both blood [lactate] and V̇O 2 were significantly greater, and exercise intolerance occurred before 30 min, at a power output slightly above MLSS MOD .
A novel method for evaluating blood lactate kinetics during MLSS TRAD protocol produces MLSS MOD that is not different from CP and better represents the heavy to severe exercise domain boundary.
本研究旨在开发一种新方法，通过评估在用于评估最大乳酸稳态（MLSS）的恒定功率输出运动试验期间的血乳酸积累速率，更准确地界定重度到极重度运动领域的边界。
八名训练有素的男性自行车运动员完成了五项长达30分钟的运动测试，以确定传统的MLSS（MLSS TRAD），并另外进行了四项最大测试以确定临界功率（CP）。将MLSS测试中10分钟至运动结束时血[乳酸]的变化率与相应的功率输出进行绘图，并使用两段线性回归模型来确定乳酸积累与功率输出之间的个体化断点（改良MLSS [MLSS MOD]）。
MLSS MOD显著高于MLSS TRAD（297±41 vs 278±41 W，P<0.001），但与CP无显著差异（297±41 W，P>0.05）；MLSS MOD和CP紧密相关（r = 0.97，偏差=-0.52 W，SEE = 10 W，一致性界限=-20至19 W）。血[乳酸]和V̇O 2的变化率均显著更高，并且在30分钟之前，在略高于MLSS MOD的功率输出时出现运动不耐受。
一种在MLSS TRAD方案期间评估血乳酸动力学的新方法产生的MLSS MOD与CP无差异，并且能更好地代表重度到极重度运动领域的边界。
