Rosendal L, Blangsted A K, Kristiansen J, Søgaard K, Langberg H, Sjøgaard G, Kjaer M
National Institute of Occupational Health, Copenhagen, Denmark.
Acta Physiol Scand. 2004 Dec;182(4):379-88. doi: 10.1111/j.1365-201X.2004.01356.x.
Local muscle metabolic responses to repetitive low-force contractions and to intense static contractions were studied by microdialysis in humans.
Microdialysate and electromyography (EMG) were sampled from the trapezius muscle, mixed venous blood samples were taken and perceived exertion was rated (0-9) before and during 20 min of standardized repetitive arm movement (REP), 60 min recovery (R1), and 10 min 90 degrees sustained arm position (SUS) at 20% maximum voluntary contraction, followed by 60 min recovery (R2) in six healthy male participants (28-33 years).
Average muscle activity was 8 +/- 2% of EMGmax-RMS (mean +/-SEM) during REP and 22 +/- 5% of EMGmax-RMS during SUS. Perceived exertion increased from 0 to 3.2 +/- 0.5 during REP and from 0 to 8.5 +/- 0.3 during SUS. During REP interstitial muscle lactate increased from 2.1 +/- 0.2 to 2.9 +/- 0.2 mmol L(-1) (P < 0.001) and returned to the baseline level during R1, while dialysate [K+] increased from 3.8 +/- 0.2 to 4.7 +/- 0.2 mmol L(-1) (P < 0.002) and returned to 3.8 +/- 0.2 mmol L(-1) during R1. In contrast, plasma lactate and [K+] remained unchanged. During SUS interstitial muscle lactate increased from 2.3 +/- 0.2 to 3.3 +/- 0.3 mmol L(-1) (P < 0.003), increased further to 6.5 +/- 1.3 mmol L(-1) post-exercise (P < 0.001) and returned to baseline levels during R2. Dialysate [K+] increased from 3.9 +/- 0.2 to 4.6 +/- 0.2 mmol L(-1) (P < 0.05) and returned to baseline level during R2. Plasma lactate increased significantly during SUS whereas plasma [K+] was unchanged. During REP and SUS interstitial pyruvate was unchanged but increased in the post-exercise period proportional to the exercise intensity.
The microdialysis technique was effective in revealing muscle metabolic events that were not found systemically. Furthermore, the trapezius muscle showed an anaerobic metabolism during low-force contraction, which could indicate inhomogeneous muscle activation.
通过微透析技术研究人体局部肌肉对重复性低强度收缩和高强度静态收缩的代谢反应。
在6名健康男性参与者（28 - 33岁）中，于标准化重复性手臂运动（REP）20分钟、恢复60分钟（R1）、20%最大自主收缩下90度持续手臂姿势（SUS）10分钟以及随后的恢复60分钟（R2）过程中，从斜方肌采集微透析液和肌电图（EMG）样本，采集混合静脉血样本并评估主观用力程度（0 - 9级）。
REP期间平均肌肉活动为EMGmax - RMS的8±2%（均值±标准误），SUS期间为EMGmax - RMS的22±5%。主观用力程度在REP期间从0增加到3.2±0.5，在SUS期间从0增加到8.5±0.3。REP期间，肌肉间质乳酸从2.1±0.2 mmol/L增加到2.9±0.2 mmol/L（P < 0.001），并在R1期间恢复到基线水平，而透析液[K⁺]从3.8±0.2 mmol/L增加到4.7±0.2 mmol/L（P < 0.002），并在R1期间恢复到3.8±0.2 mmol/L。相比之下，血浆乳酸和[K⁺]保持不变。SUS期间，肌肉间质乳酸从2.3±0.2 mmol/L增加到3.3±0.3 mmol/L（P < 0.003），运动后进一步增加到6.5±1.3 mmol/L（P < 0.001），并在R2期间恢复到基线水平。透析液[K⁺]从3.9±0.2 mmol/L增加到4.6±0.2 mmol/L（P < 0.05），并在R2期间恢复到基线水平。SUS期间血浆乳酸显著增加，而血浆[K⁺]保持不变。REP和SUS期间肌肉间质丙酮酸无变化，但运动后与运动强度成比例增加。
微透析技术有效地揭示了全身性未发现的肌肉代谢事件。此外，斜方肌在低强度收缩期间表现出无氧代谢，这可能表明肌肉激活不均匀。
