School of Sport and Exercise Sciences, University of Kent, Canterbury, Kent, England, UK.
School of Sport and Exercise Sciences, University of Kent, Canterbury, Kent, England, UK.
Exp Gerontol. 2023 May;175:112156. doi: 10.1016/j.exger.2023.112156. Epub 2023 Mar 28.
In-vivo techniques using near-infrared spectroscopy (NIRS) have been developed to assess skeletal muscle mitochondrial oxidative capacity. However, the test-retest and day-to-day reliability of NIRS-derived mitochondrial oxidative capacity has yet to be established in older individuals. Therefore, the primary aim of this study was to determine the day-to-day and test-retest reliability of NIRS-derived mitochondrial oxidative capacity in older adults. The secondary aim was to examine the relationship between NIRS-derived mitochondrial capacity and whole-body aerobic fitness.
Twenty-four healthy individuals (19 M, 5F; aged 60 ± 4 years; maximal oxygen uptake (V̇O) = 41.2 ± 6.8 ml.kg.min) completed three visits to the laboratory. Visit one assessed isometric maximal voluntary contractions of the knee extensors and aerobic capacity through an incremental exercise test. In visits two and three participants completed two measurements of NIRS-derived mitochondrial oxidative capacity in the vastus lateralis (VL).
NIRS-derived mitochondrial oxidative capacity was found to have good to excellent day-to-day reliability (Day 1 vs Day 2; coefficient of variation (CV) = 7.0 %; standard error of measurement (SEM) = 5.2; intra-class correlation coefficient (ICC) = 0.94) and test re-test reliability (Day 1 [Test 1 vs Test 2]; CV = 5.0 %; SEM = 3.7; ICC 0.97 and Day 2 [Test 1 vs Test 2]; CV = 6.3 %; SEM = 4.9; ICC = 0.93). NIRS-derived mitochondrial oxidative capacity was found to be significantly correlated with V̇O (r = -0.61; R = 0.37; P = 0.002), oxygen uptake at the gas exchange threshold (r = -0.49; R = 0.24; P = 0.02), and oxygen uptake at the respiratory compensation point (r = -0.57; R = 0.32; P = 0.004).
NIRS provides a reliable method for deriving a measure of VL mitochondrial oxidative capacity in highly active older adults and demonstrates a significant relationship with measures of whole-body aerobic fitness.
使用近红外光谱（NIRS）的体内技术已被开发用于评估骨骼肌线粒体的氧化能力。然而，NIRS 衍生的线粒体氧化能力的测试-重测和日常可靠性尚未在老年人中得到确定。因此，本研究的主要目的是确定老年人中 NIRS 衍生的线粒体氧化能力的日常和测试-重测可靠性。次要目的是检查 NIRS 衍生的线粒体容量与全身有氧健身之间的关系。
24 名健康个体（19 名男性，5 名女性；年龄 60±4 岁；最大摄氧量（V̇O）=41.2±6.8ml.kg.min）完成了三次实验室访问。第一次访问评估了股四头肌的等长最大自愿收缩和通过递增运动测试的有氧能力。在第二次和第三次访问中，参与者在股外侧肌（VL）上完成了两次 NIRS 衍生的线粒体氧化能力测量。
NIRS 衍生的线粒体氧化能力具有良好到极好的日常可靠性（第 1 天与第 2 天；变异系数（CV）=7.0%；测量标准误差（SEM）=5.2；组内相关系数（ICC）=0.94）和测试-重测可靠性（第 1 天[测试 1 与测试 2]；CV=5.0%；SEM=3.7；ICC 0.97 和第 2 天[测试 1 与测试 2]；CV=6.3%；SEM=4.9；ICC=0.93）。NIRS 衍生的线粒体氧化能力与 V̇O（r=-0.61；R=0.37；P=0.002）、换气阈下的摄氧量（r=-0.49；R=0.24；P=0.02）和呼吸补偿点下的摄氧量（r=-0.57；R=0.32；P=0.004）呈显著相关。
NIRS 提供了一种可靠的方法来测量高度活跃的老年人股外侧肌线粒体的氧化能力，并与全身有氧健身的测量结果显示出显著的关系。
