Single muscle fiber function with concurrent exercise or nutrition countermeasures during 60 days of bed rest in women
Single muscle fiber function with concurrent exercise or nutrition countermeasures during 60 days of bed rest in women
复制标题
DOI：
10.1152/japplphysiol.00560.2007
复制
发表时间：
2007-10-01
影响因子：
3.3
通讯作者：
Trappe, Todd
中科院分区：
文献类型：
--
作者：
Trappe, Scott;Creer, Andrew;Trappe, Todd
关于女性骨骼肌特性的信息有限，并采取对策计划来保护卸载引起的萎缩。目前的研究验证了一个假设，即同时进行有氧运动和阻力运动训练计划将保持大小d的慢肌纤维和快肌纤维的收缩功能。第二个目的是检验富含亮氨酸的高蛋白饮食会部分减弱单纤维特征的假设。在卧床休息前和第59天，从对照组（BR; n = 8）、营养组（BRN; n = 8）或运动组（BRE; n = 8）中获得股外侧肌活检。研究了单个肌纤维的直径、峰值力（P.）收缩速度和功率。BR组的肌球蛋白重链（MHC）I直径（-14%）、P.（-35%）和功率（-42%）和MHC IIa直径（-16%）和P.（-31%; P = 0.06）减少（P <0.05），MHC混合纤维增加（P < 0.05）。BRN个体中MHC I（-19至-44%）和IIa（-21%至-30%）纤维的大小和功能以及MHC分布的变化与BR组中的结果相似。在BRE条件下，MHC I和IIa的大小和收缩功能在卧床休息期间得到保留。这些数据表明，在60天的卧床休息期间，同时进行的运动计划保留了股外侧肌的肌细胞轮廓。为了对抗肌肉萎缩和长期卸载的功能，本研究中使用的运动处方计划应被视为大腿肌肉的可行训练计划，而所使用的营养干预不能被推荐作为骨骼肌的对策。
There is limited information on skeletal muscle properties in women with unloading and countermeasure programs to protect the unloading-induced atrophy. The current investigation tested the hypothesis that a concur-rent aerobic and resistance exercise training program would preserve size d contractile function of slow- and fast-twitch muscle fibers. A secondary objective was to test the hypothesis that a leucine-enriched high-protein diet would partially attenuate single fiber characteristics. Vastus lateralis muscle biopsies were obtained before and on day 59 of bed rest from a control (BR; n = 8), nutrition (BRN; n = 8), or exercise (BRE; n = 8) group. Single muscle fibers were studied for diameter, peak force (P.), contractile velocity, and power. Those in the BR group had a decrease (P < 0.05) in myosin heavy chain (MHC) I diameter (-14%), P. (-35%), and power (-42%) and MHC IIa diameter (- 16%) and P. (- 3 1 %; P = 0.06) and an increase (P < 0.05) in MHC hybrid fibers. Changes in size and function of MHC I (-19 to -44%) and IIa (-21% to -30%) fibers and MHC distribution in BRN individuals were similar to results in the BR group. In BRE conditions, MHC I and IIa size and contractile function were preserved during bed rest. These data show that the concurrent exercise program preserved the myocellular profile of the vastus lateralis muscle during 60-day bed rest. To combat muscle atrophy and function with long-term unloading, the exercise prescription program used in this study should be considered as a viable training program for the upper leg muscles, whereas the nutritional intervention used cannot be recommended as a countermeasure for skeletal muscle.