Department of Kinesiology, University of Georgia, Athens, GA 30602, USA.
Med Sci Sports Exerc. 2013 May;45(5):869-75. doi: 10.1249/MSS.0b013e31827e0eb6.
To determine whether near-infrared spectroscopy (NIRS) measurements of muscle mitochondrial function could detect the expected differences between endurance-trained athletes (n = 8) and inactive subjects (n = 8).
Muscle oxygen consumption (mV˙O2) of the vastus lateralis was measured with continuous-wave NIRS using transient arterial occlusions. The recovery rate of mV˙O2 after electrical stimulation was fit to an exponential curve, with the time constant (Tc) used as an index of mitochondrial capacity. Whole-body peak oxygen uptake was determined by indirect calorimetry during a continuous ramp protocol on a cycle ergometer.
Whole-body peak oxygen uptake values for endurance-trained and inactive controls were 73.5 ± 9.1 and 33.7 ± 5.9 mL·kg·min, respectively (P < 0.001). The recovery rates of mV˙O2 after exercise for endurance training were 18.4 ± 3.2 and 18.8 ± 2.5 s, whereas those for inactive controls were 32.4 ± 5.2 and 34.9 ± 5.9 s for the shallow and deep channels, respectively (P < 0.001 for comparison between groups). Resting mV˙O2 was 0.52%·s ± 0.22%·s for endurance athletes and 0.77%·s ± 0.82%·s for inactive controls (P = 0.42).
The recovery rates of mV˙O2 after exercise in endurance athletes were almost twofold faster than inactive subjects measured with NIRS, consistent with previous studies using muscle biopsies and magnetic resonance spectroscopy. Our results support the use of NIRS measurements of the recovery of oxygen consumption to assess muscle oxidative capacity.
确定近红外光谱（NIRS）测量肌肉线粒体功能是否能够检测到经过耐力训练的运动员（n=8）和不活动受试者（n=8）之间的预期差异。
使用连续波 NIRS 通过短暂动脉闭塞测量股外侧肌的肌肉耗氧量（mV˙O2）。电刺激后 mV˙O2 的恢复速率拟合为指数曲线，时间常数（Tc）用作线粒体容量的指标。在自行车测功计上进行连续斜坡方案时，通过间接热量测定法确定全身峰值摄氧量。
经过耐力训练和不活动对照组的全身峰值摄氧量值分别为 73.5±9.1 和 33.7±5.9 mL·kg·min（P<0.001）。运动后 mV˙O2 的恢复速率在耐力训练中为 18.4±3.2 和 18.8±2.5 s，而在不活动对照组中分别为 32.4±5.2 和 34.9±5.9 s（组间比较 P<0.001）。静息 mV˙O2 对于耐力运动员为 0.52%·s±0.22%·s，对于不活动对照组为 0.77%·s±0.82%·s（P=0.42）。
与使用肌肉活检和磁共振波谱学的先前研究一致，使用 NIRS 测量运动后 mV˙O2 的恢复，耐力运动员的恢复速度几乎是不活动受试者的两倍。我们的结果支持使用 NIRS 测量耗氧量的恢复来评估肌肉氧化能力。
