Snyder Ann C, Parmenter Mark A
Department of Human Movement Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA.
J Strength Cond Res. 2009 Sep;23(6):1833-40. doi: 10.1519/JSC.0b013e3181ad3362.
Maximal steady state (MSS) speed can be determined from blood lactate concentration (HLa); however, this method is not optimal. The purpose of this study was to determine whether near-infrared spectroscopy (NIRS) technology could be used to detect a breakpoint in percent oxygen saturation (StO2) of the muscle and whether the determined breakpoint exercise intensity could be used to determine MSS exercise intensity. Sixteen distance runners and triathletes (men = 9, VO2max = 64.9 +/- 4.9 ml x kg(-1) x min(-1), women = 7, VO2max = 50.8 +/- 7.0 ml x kg(-1) x min(-1)) completed an incremental exercise test. A change from linearity when plotting StO2 or HLa vs. running speed was defined as the breakpoint. The subjects then completed constant speed runs to determine maximal lactate steady state (MLSS). In 12 subjects, breakpoints were identified for both HLa and StO2 values. Predicted MLSS velocities from HLa breakpoint (12.76 +/- 1.63 km x h(-1)), StO2 breakpoint (12.84 +/- 1.58 km x h(-1)), and 4 mM HLa (13.49 +/- 1.71 km x h(-1)) methods from the incremental test did not differ from MLSS speeds (13.04 +/- 2.03 km x h(-1)). A Bland and Altman analysis of agreement between the MLSS and the StO2 breakpoint speeds resulted in a mean difference of 0.14 +/- 0.36, whereas the mean difference between MLSS and HLa breakpoint speeds was 0.19 +/- 0.43. During the incremental test, no StO2 breakpoint was determined in 2 subjects, whereas 2 subjects had no HLa breakpoint. The results of this study lead us to conclude that the NIRS determination of StO2 is a noninvasive technique that is comparable with HLa in determining MSS intensity and therefore appropriate for use in determining exercise training intensity.
最大稳态（MSS）速度可通过血乳酸浓度（HLa）来确定；然而，这种方法并非最佳。本研究的目的是确定近红外光谱（NIRS）技术是否可用于检测肌肉氧饱和度百分比（StO2）的断点，以及所确定的断点运动强度是否可用于确定MSS运动强度。16名长跑运动员和铁人三项运动员（男性9名，最大摄氧量[VO2max]=64.9±4.9毫升·千克⁻¹·分钟⁻¹，女性7名，VO2max=50.8±7.0毫升·千克⁻¹·分钟⁻¹）完成了递增运动测试。绘制StO2或HLa与跑步速度关系图时线性关系的变化被定义为断点。然后受试者完成恒速跑步以确定最大乳酸稳态（MLSS）。在12名受试者中，确定了HLa和StO2值的断点。递增测试中，根据HLa断点（12.76±1.63千米·小时⁻¹）、StO2断点（12.84±1.58千米·小时⁻¹）和4毫摩尔HLa（13.49±1.71千米·小时⁻¹）方法预测的MLSS速度与MLSS实际速度（13.04±2.03千米·小时⁻¹）无差异。对MLSS和StO2断点速度之间的一致性进行Bland-Altman分析，平均差异为0.14±0.36，而MLSS和HLa断点速度之间的平均差异为0.19±0.43。在递增测试中，2名受试者未确定StO2断点，而2名受试者没有HLa断点。本研究结果使我们得出结论，NIRS对StO2的测定是一种非侵入性技术，在确定MSS强度方面与HLa相当，因此适用于确定运动训练强度。
