Arnold Jem I, Yogev Assaf, Nelson Hannah, van Hooff Martijn, Koehle Michael S
School of Kinesiology, The University of British Columbia, Vancouver, BC, Canada.
Department of Pathology and Laboratory Medicine, The University of British Columbia, Vancouver, BC, Canada.
Front Physiol. 2024 Aug 14;15:1449384. doi: 10.3389/fphys.2024.1449384. eCollection 2024.
Wearable near-infrared spectroscopy (NIRS) can be used during dynamic exercise to reflect the balance of muscle oxygen delivery and uptake. This study describes the behaviour and reliability of postexercise reoxygenation with NIRS as a function of exercise intensity at four muscle sites during an incremental cycling test. We discuss physiological components of faster and slower reoxygenation kinetics in the context of sport science and clinical applications. We hypothesised that reoxygenation would be slower at higher intensity, and that locomotor muscles would be faster than accessory muscles. We quantified test-retest reliability and agreement for each site.
Twenty-one trained cyclists performed two trials of an incremental cycling protocol with 5-min work stages and 1-min rest between stages. NIRS was recorded from the locomotor vastus lateralis and rectus femoris muscles, and accessory lumbar paraspinal and lateral deltoid muscles. Reoxygenation time course was analysed as the half-recovery time (HRT) from the end of work to half of the peak reoxygenation amplitude during rest. Coefficient of variability (CV) between participants, standard error of the measurement (SEM) within participants, and intraclass correlation coefficient (ICC) for test-retest reliability were evaluated at 50%, 75%, and 100% peak workloads. A linear mixed-effects model was used to compare differences between workloads and muscle sites.
HRT was slower with increasing workload in the VL, RF, and PS, but not DL. VL had the fastest reoxygenation (lowest HRT) across muscle sites at all workloads (HRT = 8, 12, 17 s at 50%, 75%, 100% workload, respectively). VL also had the greatest reliability and agreement. HRT was sequentially slower between muscle sites in the order of VL < RF < PS < DL, and reliability was lower than for the VL.
This study highlights the potential for using wearable NIRS on multiple muscle sites during exercise. Reoxygenation kinetics differ between local muscle sites with increasing intensity. Moderate-to-good reliability in the VL support its increasing use in sport science and clinical applications. Lower reliability in other muscle sites suggest they are not appropriate to be used alone, but may add information when combined to better reflect systemic intensity and fatigue during exercise at different intensities.
可穿戴近红外光谱技术（NIRS）可在动态运动过程中用于反映肌肉氧输送与摄取的平衡。本研究描述了在递增式自行车测试期间，NIRS测量的运动后复氧情况及其可靠性与运动强度的关系，该测试涉及四个肌肉部位。我们在运动科学和临床应用背景下讨论了快速和慢速复氧动力学的生理组成部分。我们假设高强度时复氧会更慢，且运动肌的复氧速度会比辅助肌更快。我们对每个部位的重测信度进行了量化。
21名受过训练的自行车运动员进行了两次递增式自行车测试，每个工作阶段持续5分钟，阶段间休息1分钟。使用NIRS记录运动肌股外侧肌和股直肌，以及辅助肌腰旁肌和三角肌的情况。复氧时间过程分析为从工作结束到休息期间复氧峰值幅度一半时的半恢复时间（HRT）。在50%、75%和100%峰值工作量时，评估了参与者之间的变异系数（CV）、参与者内部的测量标准误差（SEM）以及重测信度的组内相关系数（ICC）。使用线性混合效应模型比较工作量和肌肉部位之间的差异。
在股外侧肌（VL）、股直肌（RF）和腰旁肌（PS）中，随着工作量增加HRT变慢，但在三角肌（DL）中并非如此。在所有工作量下，VL在各肌肉部位中复氧最快（HRT最低）（在50%、75%、100%工作量时，HRT分别为8秒、12秒、17秒）。VL的可靠性和一致性也最高。HRT在肌肉部位之间依次变慢，顺序为VL < RF < PS < DL，且其可靠性低于VL。
本研究突出了在运动期间对多个肌肉部位使用可穿戴NIRS的潜力。随着强度增加，局部肌肉部位的复氧动力学有所不同。VL具有中等到良好的可靠性，这支持了其在运动科学和临床应用中越来越多的使用。其他肌肉部位较低的可靠性表明它们不适宜单独使用，但在联合使用时可能会增加信息，以更好地反映不同强度运动期间的全身强度和疲劳情况。
