Spencer Matthew D, Amano Tatsuro, Kondo Narihiko, Kowalchuk John M, Koga Shunsaku
Kobe Design University, Kobe, Hyogo, Japan; The University of Western Ontario, London, Ontario, Canada; and.
Kobe University, Kobe, Hyogo, Japan.
J Appl Physiol (1985). 2014 Nov 15;117(10):1199-206. doi: 10.1152/japplphysiol.00060.2014. Epub 2014 Sep 25.
The present study compared peak muscle deoxygenation ([HHb]peak) responses at three quadriceps sites during occlusion (OCC), ramp incremental (RI), severe- (SVR) and moderate-intensity (MOD) exercise. Seven healthy men (25 ± 4 yr) each completed a stationary cycling RI (20 W/min) test to determine [HHb]peak [at distal and proximal vastus lateralis (VLD and VLP) and rectus femoris (RF)], peak V̇O2 (V̇O(2peak)), gas exchange threshold (GET), and peak work rate (WR(peak)). Subjects also completed MOD (WR = 80% GET) and SVR exercise (WR corresponding to 120% V̇O(2peak)) with absolute [HHb] (quantified by multichannel, time-resolved near-infrared spectroscopy) and pulmonary VO2 (V̇O(2p)) monitored continuously. Additionally, [HHb] and total hemoglobin ([Hb]tot) were monitored at rest and during subsequent OCC (250 mmHg). Site-specific adipose tissue thickness was assessed (B-mode ultrasound), and its relationship with resting [Hb]tot was used to correct absolute [HHb]. For VLD and RF, [HHb]peak was higher (P < 0.05) during OCC (VLD = 111 ± 38, RF = 114 ± 26 μM) than RI (VLD 64 ± 14, RF = 85 ± 20) and SVR (VLD = 63 ± 13, RF = 81 ± 18). [HHb]peak was similar (P > 0.05) across these conditions at the VLP (OCC = 67 ± 17, RI = 69 ± 17, SVR = 63 ± 17 μM). [HHb] peaked and then decreased prior to exercise cessation during SVR at all three muscle sites. [HHb]peak during MOD was consistently lower than other conditions at all sites. A "[HHb] reserve" exists during intense cycling at the VLD and RF, likely implying either sufficient blood flow to meet oxidative demands or insufficient diffusion time for complete equilibration. In VLP this [HHb] reserve was absent, suggesting that a critical PO2 may be challenged during intense cycling.
本研究比较了在闭塞（OCC）、斜坡递增（RI）、高强度（SVR）和中等强度（MOD）运动期间，股四头肌三个部位的肌肉脱氧峰值（[HHb]peak）反应。七名健康男性（25±4岁）每人完成了一次固定自行车RI（20W/分钟）测试，以确定[HHb]peak[在股外侧肌远端和近端（VLD和VLP）以及股直肌（RF）处]、峰值摄氧量（V̇O2peak）、气体交换阈值（GET）和峰值工作率（WRpeak）。受试者还完成了MOD（WR=80%GET）和SVR运动（WR对应于120%V̇O2peak），同时通过多通道时间分辨近红外光谱法连续监测绝对[HHb]和肺摄氧量（V̇O2p）。此外，在静息状态和随后的OCC（250mmHg）期间监测[HHb]和总血红蛋白（[Hb]tot）。评估了各部位的脂肪组织厚度（B型超声），并利用其与静息[Hb]tot的关系对绝对[HHb]进行校正。对于VLD和RF，OCC期间的[HHb]peak较高（P<0.05）（VLD=111±38，RF=114±26μM），高于RI（VLD 64±14，RF=85±20）和SVR（VLD=63±13，RF=81±18）。在这些条件下，VLP处的[HHb]peak相似（P>0.05）（OCC=67±17，RI=69±17，SVR=63±17μM）。在SVR期间，所有三个肌肉部位的[HHb]在运动停止前达到峰值然后下降。MOD期间所有部位的[HHb]peak始终低于其他条件。在VLD和RF进行高强度骑行期间存在“[HHb]储备”，这可能意味着要么有足够的血流来满足氧化需求，要么扩散时间不足无法实现完全平衡。在VLP中不存在这种[HHb]储备，这表明在高强度骑行期间临界氧分压可能受到挑战。
