Nuhr Martin, Crevenna Richard, Gohlsch Bärbel, Bittner Christian, Pleiner Johannes, Wiesinger Günther, Fialka-Moser Veronika, Quittan Michael, Pette Dirk
Universitätsklinik für Physikalische Medizin und Rehabilitation, AKH Wien, Währringer Gürtel 18-20, 1090 Vienna, Austria.
Eur J Appl Physiol. 2003 Apr;89(2):202-8. doi: 10.1007/s00421-003-0792-8. Epub 2003 Feb 28.
The present study was undertaken to investigate in a randomized controlled trial the effects of chronic (10 weeks, 4 h per day, 7 days per week) low-frequency (15 Hz) stimulation (CLFS) of the knee extensor and hamstring muscles of both legs in healthy volunteers via surface electrodes. A control group (n=10) underwent the same treatment (sham stimulation) as the CLFS-treated group (n=10), except that stimulation intensity was kept at a level which did not evoke contractions. Biopsy samples were taken before the onset and after cessation of stimulation from the right vastus lateralis muscle of all subjects. The biopsy samples were analyzed for changes in myosin heavy chain (MHC) isoforms and activities of citrate synthase (CS) and glyceraldehyde phosphate dehydrogenase (GAPDH) as markers of aerobic-oxidative and anaerobic pathways of energy metabolism, respectively. In addition, functional properties, i.e., oxygen consumption (VO(2)) and work capacity, were assessed. Sham stimulation did not affect the functional properties and had no detectable effect on MHC isoform and enzyme activity patterns. Conversely, CLFS induced changes in the MHC isoform pattern in the fast-to-slow direction with an approximately 20% decrease in the relative concentration of MHCIId/x (from 28% to 22%) and an approximately 10% increase in the relative concentration of MHCI (from 30% to 34%). In addition, CLFS led to a approximately 9% increase in the activity of CS concomitant with an approximatley 7% decrease in the activity of GAPDH. This increase in aerobic-oxidative capacity was accompanied by improved work capacity and VO(2) at the anaerobic threshold by 26% and 20%, respectively.
本研究旨在通过随机对照试验，利用表面电极对健康志愿者双腿的股四头肌和腘绳肌进行慢性（10周，每天4小时，每周7天）低频（15赫兹）刺激（CLFS），以探究其效果。对照组（n = 10）接受与CLFS治疗组（n = 10）相同的治疗（假刺激），不同之处在于刺激强度保持在不会引起肌肉收缩的水平。在所有受试者的右侧股外侧肌，于刺激开始前和停止后采集活检样本。对活检样本进行分析，以检测肌球蛋白重链（MHC）亚型的变化，以及分别作为能量代谢有氧氧化和无氧途径标志物的柠檬酸合酶（CS）和甘油醛-3-磷酸脱氢酶（GAPDH）的活性。此外，还评估了功能特性，即耗氧量（VO₂）和工作能力。假刺激不影响功能特性，对MHC亚型和酶活性模式也无明显影响。相反，CLFS导致MHC亚型模式从快肌向慢肌方向转变，MHCIId/x的相对浓度降低约20%（从28%降至22%），MHCI的相对浓度增加约10%（从30%增至34%）。此外，CLFS使CS的活性增加约9%，同时GAPDH的活性降低约7%。有氧氧化能力的这种增加伴随着工作能力的改善，无氧阈值时的VO₂分别提高了26%和20%。
