Force-velocity-power and force-pCa relationships of human soleus fibers after 17 days of bed rest.
Force-velocity-power and force-pCa relationships of human soleus fibers after 17 days of bed rest.
复制标题
卧床休息 17 天后人比目鱼肌纤维的力-速度-功率和力-PCA 关系。
DOI：
10.1152/jappl.1998.85.5.1949
复制
发表时间：
1998
影响因子：
3.3
通讯作者：
R. Fitts
中科院分区：
文献类型：
--
作者：
J. Widrick;K. Norenberg;J. Romatowski;C. Blaser;M. Karhánek;J. Sherwood;S. Trappe;T. Trappe;D. Costill;R. Fitts
后肢悬吊后，大鼠比目鱼肌肌纤维的峰值功率和钙敏感性降低。为了检测人类对不负重的反应，我们从8名成年男性卧床前和卧床后17天(BR)后立即进行比目鱼肌活检。单个化学蒙皮纤维安装在力传感器和伺服控制的位置马达之间，并以最大(等张特性)和/或次最大(对钙的敏感性)水平的游离钙激活。凝胶电泳法显示BR前后的纤维均表达I型肌球蛋白重链。从一名受试者获得的BR后纤维显示峰值功率和对钙的敏感性增加。相比之下，从其余7名受试者身上获得的BR后纤维的峰值功率平均下降了11%(P<；0.05)，每个人的峰值功率下降了7%-27%。这些受试者的BR后纤维直径较小，在与峰值功率相关的缩短速度下产生的力减少21%。然而，在BR后的光纤中，峰值功率输出时的缩短速度提高了13%，这部分补偿了它们较低的力。这七个受试者的BR后纤维对游离钙的敏感性也降低(P<；0.05)。这些结果表明，BR后人类下肢伸肌功能能力的降低可能部分是由于跨桥收缩机制的改变所致。
Soleus muscle fibers from the rat display a reduction in peak power and Ca2+ sensitivity after hindlimb suspension. To examine human responses to non-weight bearing, we obtained soleus biopsies from eight adult men before and immediately after 17 days of bed rest (BR). Single chemically skinned fibers were mounted between a force transducer and a servo-controlled position motor and activated with maximal (isotonic properties) and/or submaximal (Ca2+ sensitivity) levels of free Ca2+. Gel electrophoresis indicated that all pre- and post-BR fibers expressed type I myosin heavy chain. Post-BR fibers obtained from one subject displayed increases in peak power and Ca2+ sensitivity. In contrast, post-BR fibers obtained from the seven remaining subjects showed an average 11% reduction in peak power (P < 0.05), with each individual displaying a 7-27% reduction in this variable. Post-BR fibers from these subjects were smaller in diameter and produced 21% less force at the shortening velocity associated with peak power. However, the shortening velocity at peak power output was elevated 13% in the post-BR fibers, which partially compensated for their lower force. Post-BR fibers from these same seven subjects also displayed a reduced sensitivity to free Ca2+ (P < 0.05). These results indicate that the reduced functional capacity of human lower limb extensor muscles after BR may be in part caused by alterations in the cross-bridge mechanisms of contraction.
精英跑步大师和久坐男子的单肌纤维的力-速度和力-功率特性。
DOI：
10.1152/ajpcell.1996.271.2.c676
发表时间：
1996
期刊：
The American journal of physiology.
影响因子：
--
作者：
Widrick,JJ;Trappe,SW;Costill,DL;Fitts,RH
通讯作者：
Fitts,RH