Yogev Assaf, Arnold Jem, Nelson Hannah, Clarke David C, Guenette Jordan A, Sporer Ben C, Koehle Michael S
Environmental Physiology Laboratory, The University of British Columbia, School of Kinesiology, Vancouver, BC, Canada.
Department of Biomedical Physiology and Kinesiology and Sports Analytics Group, Simon Fraser University, Burnaby, BC, Canada.
Front Sports Act Living. 2023 Aug 4;5:1143393. doi: 10.3389/fspor.2023.1143393. eCollection 2023.
Wearable near-infrared spectroscopy (NIRS) measurements of muscle oxygen saturation (SmO) demonstrated good test-retest reliability at rest. We hypothesized SmO measured with the Moxy monitor at the vastus lateralis (VL) would demonstrate good reliability across intensities. For relative reliability, SmO will be lower than volume of oxygen consumption (V̇O) and heart rate (HR), higher than concentration of blood lactate accumulation ([BLa]) and rating of perceived exertion (RPE). We aimed to estimate the reliability of SmO and common physiological measures across exercise intensities, as well as to quantify within-participant agreement between sessions.
Twenty-one trained cyclists completed two trials of an incremental multi-stage cycling test with 5 min constant workload steps starting at 1.0 watt per kg bodyweight (W·kg) and increasing by 0.5 W kg per step, separated by 1 min passive recovery intervals until maximal task tolerance. SmO, HR, V̇O, [BLa], and RPE were recorded for each stage. Continuous measures were averaged over the final 60 s of each stage. Relative reliability at the lowest, median, and highest work stages was quantified as intraclass correlation coefficient (ICC). Absolute reliability and within-subject agreement were quantified as standard error of the measurement (SEM) and minimum detectable change (MDC).
Comparisons between trials showed no significant differences within each exercise intensity for all outcome variables. ICC for SmO was 0.81-0.90 across exercise intensity. ICC for HR, V̇O, [BLa], and RPE were 0.87-0.92, 0.73-0.97, 0.44-0.74, 0.29-0.70, respectively. SEM (95% CI) for SmO was 5 (3-7), 6 (4-9), and 7 (5-10)%, and MDC was 12%, 16%, and 18%.
Our results demonstrate good-to-excellent test-retest reliability for SmO across intensity during an incremental multi-stage cycling test. V̇O and HR had excellent reliability, higher than SmO. [BLa] and RPE had lower reliability than SmO. Muscle oxygen saturation measured by wearable NIRS was found to have similar reliability to V̇O and HR, and higher than [BLa] and RPE across exercise intensity, suggesting that it is appropriate for everyday use as a non-invasive method of monitoring internal load alongside other metrics.
可穿戴式近红外光谱技术（NIRS）对肌肉氧饱和度（SmO）的测量在静息状态下具有良好的重测信度。我们假设，使用Moxy监测仪在股外侧肌（VL）测量的SmO在不同强度下都将表现出良好的信度。对于相对信度，SmO将低于耗氧量（V̇O）和心率（HR），高于血乳酸积累浓度（[BLa]）和主观用力程度分级（RPE）。我们旨在评估不同运动强度下SmO及常见生理指标的信度，并量化各次测试之间的受试者内一致性。
21名受过训练的自行车运动员完成了两次递增多阶段自行车测试，每次测试从1.0瓦/千克体重（W·kg）开始，以0.5 W/kg的步长递增，每个工作负荷保持5分钟，中间间隔1分钟的被动恢复时间，直至达到最大任务耐受量。记录每个阶段的SmO、HR、V̇O、[BLa]和RPE。连续测量值取每个阶段最后60秒的平均值。最低、中间和最高工作阶段的相对信度用组内相关系数（ICC）进行量化。绝对信度和受试者内一致性用测量标准误（SEM）和最小可检测变化（MDC）进行量化。
两次测试之间的比较表明，所有结果变量在各运动强度下均无显著差异。不同运动强度下SmO的ICC为0.81 - 0.90。HR、V̇O、[BLa]和RPE的ICC分别为0.87 - 0.92、0.73 - 0.97、0.44 - 0.74、0.29 - 0.70。SmO的SEM（95%CI）为5%（3 - 7）、6%（4 - 9）和7%（5 - 10），MDC为12%、16%和18%。
我们的结果表明，在递增多阶段自行车测试中，SmO在不同强度下具有良好至优秀的重测信度。V̇O和HR具有优秀的信度，高于SmO。[BLa]和RPE的信度低于SmO。通过可穿戴式NIRS测量的肌肉氧饱和度在不同运动强度下与V̇O和HR具有相似的信度，且高于[BLa]和RPE，这表明它作为一种非侵入性方法，与其他指标一起用于日常监测内部负荷是合适的。
