Fluckey J D, Dupont-Versteegden E E, Montague D C, Knox M, Tesch P, Peterson C A, Gaddy-Kurten D
Nutrition, Metabolism and Exercise Laboratory, Department of Geriatrics, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Acta Physiol Scand. 2002 Dec;176(4):293-300. doi: 10.1046/j.1365-201X.2002.01040.x.
Exposure to microgravity and/or spaceflight causes dramatic losses in both muscle and bone mass. In normal gravity, resistance exercise has been effectively used to increase muscle and bone mass. We tested a novel form of resistance exercise training using flywheel technology as a countermeasure to offset the loss of musculoskeletal mass during 4 weeks of adult rat hindlimb suspension (HS), an unloading model of microgravity. Male, Sprague-Dawley rats (6-month old) were operantly conditioned to perform resistance exercise, and then randomly assigned to groups of sedentary control (CON), HS, and HS with resistance exercise training (HSRT; 2 sets of approximately 21 repetitions, 3 days week(-1) for 4 weeks during suspension). In soleus, HS resulted in lower (P < 0.05) muscle mass to body mass ratio (approximately 50% of controls) and rates of protein synthesis. HSRT significantly attenuated the loss of muscle mass in soleus muscle, and rates of protein synthesis for soleus were similar for HSRT and controls. There were no differences among groups for mass or rates of protein synthesis in extensor digitorum longus. In cancellous regions of the distal femur, HS resulted in significant reductions of bone mineral density (BMD), but this was restored to control levels with HSRT. Cortical regions of the femur were not different among HS, HSRT or control groups. Together, these data suggest that resistance training using flywheel technology may be a promising tool to attenuate losses of the musculoskeletal system during periods of hindlimb unloading.
暴露于微重力和/或太空飞行会导致肌肉和骨量大幅减少。在正常重力环境下，抗阻运动已被有效用于增加肌肉和骨量。我们测试了一种使用飞轮技术的新型抗阻运动训练，作为一种对策来抵消成年大鼠后肢悬吊（HS）4周期间肌肉骨骼质量的损失，HS是一种微重力卸载模型。雄性Sprague-Dawley大鼠（6个月大）经过操作性条件训练以进行抗阻运动，然后随机分为久坐对照组（CON）、HS组以及进行抗阻运动训练的HS组（HSRT；在悬吊期间每周3天，共4周，进行2组约21次重复运动）。在比目鱼肌中，HS导致肌肉质量与体重之比降低（P<0.05）（约为对照组的50%）以及蛋白质合成速率降低。HSRT显著减轻了比目鱼肌肌肉质量的损失，并且HSRT组比目鱼肌的蛋白质合成速率与对照组相似。在趾长伸肌中，各组之间的质量或蛋白质合成速率没有差异。在股骨远端的松质骨区域，HS导致骨矿物质密度（BMD）显著降低，但通过HSRT可恢复到对照水平。股骨的皮质区域在HS组、HSRT组或对照组之间没有差异。总之，这些数据表明，使用飞轮技术的抗阻训练可能是一种有前景的工具，可减轻后肢卸载期间肌肉骨骼系统的损失。
