The isometric torque at which knee-extensor muscle reoxygenation stops
The isometric torque at which knee-extensor muscle reoxygenation stops
复制标题
DOI：
10.1249/mss.0b013e31802dd3cc
复制
发表时间：
2007-03-01
期刊：
影响因子：
--
通讯作者：
De Haan, Arnold
中科院分区：
文献类型：
--
作者：
De Ruiter, C. J.;Goudsmit, Jos F. A.;De Haan, Arnold
目的：我们研究了等长收缩过程中复氧(动脉血流入)停止时的膝关节伸肌扭矩，该扭矩是否依赖于最大扭矩能力(MTC)，以及增效剂之间是否存在差异。方法：采用髋关节和膝关节90度测力仪测量等长伸膝扭矩。在15名健康男性受试者(20-30岁)中，最大自主激活(通过叠加神经刺激建立)为90%。用近红外光谱仪(NIRS)测量股内侧肌(Vm)、股外侧肌(VL)和股直肌(RF)在20~45%MTC强度下收缩时肌肉氧合的变化，以5%的增量递增，随机顺序施加，分2天进行。在每个扭矩下，用充气压力袖带(450 Mm Hg)收缩，导致动脉完全闭塞，然后(休息10分钟)进行第二次收缩，不带袖带。结果：MTC范围为178~348 N-m。在无袖套的收缩过程中，最大脱氧量(所有氧气消耗)与有袖套时达到的最大脱氧量相似(P<；0.05)的扭矩(表示在无袖套的收缩过程中血流完全闭塞)，RF(35%MTC)显著高于两种VASI(25%MTC)。MTC与肌肉停止复氧的相对扭矩(%MTC)无显著相关性。结论：膝关节伸肌的复氧停止在低于先前报道的该肌肉血流的扭矩，这发生在不同力量的受试者中相同的%MTC，但不同增效剂的不同的%MTC。
Purpose: We investigated the knee-extensor torque at which reoxygenation (inflow of arterial blood) during an isometric contraction stopped, whether this torque depended on maximal torque capacity (MTC), and whether there were differences among the synergists. Methods: Isometric knee-extension torque was measured using a dynamometer with 90 angles in the hip and knee. Maximal voluntary activation (established with superimposed nerve stimulation) was > 90% in the 15 healthy male subjects (20-30 yr). Near-infrared spectroscopy (NIRS) was used to measure changes in muscle oxygenation of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle during submaximal isometric contractions at intensities of 20-45% MTC with 5% increments, applied in randomized order and divided over 2 d. At each torque, a contraction with an inflated pressure cuff (450 mm Hg), inducing full arterial occlusion, was followed (10 min of rest) by a second contraction without the cuff. Results: MTC ranged from 178 to 348 N-m. The torque at which maximal deoxygenation (all oxygen consumed) during contraction without the cuff became similar (P < 0.05) to the maximal deoxygenation reached with the cuff (indicative for complete occlusion of blood flow during the contraction without the cuff) was significantly higher for the RF (35% MTC) than for both vasti (25% MTC). There was no significant relation between MTC and relative (% MTC) torque at which muscle reoxygenation stopped. Conclusion: Knee-extensor reoxygenation stopped at lower torques than previously reported for blood flow in this muscle, and this occurred at the same % MTC in subjects of different strength but at different % MTC for the different synergists.