Muscle metabolism during graded quadriceps exercise in man
Muscle metabolism during graded quadriceps exercise in man
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DOI：
10.1113/jphysiol.2007.128348
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发表时间：
2007-06-15
影响因子：
5.5
通讯作者：
Kiens, Bente
中科院分区：
文献类型：
--
作者：
Helge, Jorn W.;Stallknecht, Bente;Kiens, Bente
这项研究的目的是检查局部肌肉代谢反应分级运动时，涉及的肌肉质量太小，引起显着的激素变化和局部血流限制。9名健康的禁食过夜的男性受试者进行膝关节伸展运动，两条大腿以最大功率（W-max）的25%踢45分钟（肺V-O2，V-max的23 +/- 1%），然后一条大腿以65%踢35分钟，另一条大腿以85% W-max踢35分钟（V-O2，V-max的40 +/- 1%）。进行[U-C-13]棕榈酸酯和[H-2（5）]甘油的引发恒定输注。从股动脉和两条股静脉采集血液样本，通过热稀释法测定大腿血流量。肌肉活检从m。两股外侧肌从休息到运动，在25%、65%和85% W-max下大腿血流量（0.3 +/- 0.1、2.5 +/- 0.2、3.5 +/-0.2、4.1 +/- 0.3 l min（-1））和氧摄取（0.02 +/- 0.01，0.27 +/- 0.03，0.48 +/- 0.04，0.55 +/- 0.05 l min（-1））增加（P < 0.05）。血浆脂肪酸在大腿处氧化（5 +/- 1，114 +/- 15，162 +/- 30，180 +/- 31 μ mol min（-1））增加（P < 0.05），而总大腿脂肪氧化（19 +/- 6，312 +/- 64，356 +/- 93，323 +/- 120 μ mol min（-1））从休息时增加（P < 0.05），但通过运动保持不变。大腿甘油摄取（1 +/- 1、16 +/- 4、24 +/- 10、39 +/- 8 μ mol min（-1））分别在25-65和85% W-max时从休息到运动显著增加。葡萄糖摄取和糖原分解总是随着运动强度的增加而增加。总之，在高血流量和氧气供应以及只有小的激素变化的情况下，肌肉中的总脂肪氧化从休息到轻度运动增加，但随后随着运动强度直到重度运动保持不变。然而，随着运动强度的增加，血浆游离脂肪酸的氧化增加，因此其他脂肪来源的氧化减少。这些发现与在涉及大肌肉质量的分级运动期间进行的全身测量形成对比，在此期间，脂肪氧化峰值在V-O2，V-max的60%左右。
The aim of the study was to examine local muscle metabolism in response to graded exercise when the involved muscle mass is too small to elicit marked hormonal changes and local blood flow restriction. Nine healthy overnight fasted male subjects performed knee extension exercise with both thighs kicking at 25% of maximal power (W-max) for 45 min (23 +/- 1% of pulmonary V-O2,V-max) followed by 35 min of kicking with one thigh at 65% and the other at 85% W-max (40 +/- 1% V-O2,V-max). Primed constant infusion of [U-C-13] palmitate and [H-2(5)]glycerol was carried out. Blood was sampled from a femoral artery and both femoral veins, and thigh blood flow was determined by thermodilution. Muscle biopsies were obtained from m. vastus lateralis of both thighs. From rest through exercise at 25, 65 and 85% W-max the thigh blood flow (0.3 +/- 0.1, 2.5 +/- 0.2, 3.5 +/- 0.2, 4.1 +/- 0.3 l min(-1)) and oxygen uptake (0.02 +/- 0.01, 0.27 +/- 0.03, 0.48 +/- 0.04, 0.55 +/- 0.05 l min(-1)) increased (P < 0.05). The plasma fatty acids oxidized in the thigh (5 +/- 1, 114 +/- 15, 162 +/- 30, 180 +/- 31 mu mol min(-1)) increased (P < 0.05) with exercise intensity, whereas the total thigh fat oxidation (19 +/- 6, 312 +/- 64, 356 +/- 93, 323 +/- 120 mu mol min(-1)) increased (P < 0.05) from rest, but remained unchanged through exercise. The thigh glycerol uptake (1 +/- 1, 16 +/- 4, 24 +/- 10, 39 +/- 8 mu mol min(-1)) increased significantly from rest through exercise at 25-65 and 85% W-max, respectively. Glucose uptake and glycogen breakdown always increased with exercise intensity. In conclusion, in the presence of a high blood flow and oxygen supply and only small hormonal changes, total fat oxidation in muscle increases from rest to light exercise, but then remains constant with exercise intensity up to heavy exercise. However, with increasing exercise intensity, oxidation of plasma free fatty acids increases and accordingly oxidation of other fat sources decreases. These findings are in contrast to whole body measurements performed during graded exercise involving a large muscle mass during which fat oxidation peaks at around 60% of V-O2,V-max.