Kirby C R, Ryan M J, Booth F W
Department of Physiology and Cell Biology, University of Texas Medical School, Houston 77225.
J Appl Physiol (1985). 1992 Nov;73(5):1894-9. doi: 10.1152/jappl.1992.73.5.1894.
Although various exercise paradigms have been tested, none has completely prevented muscle atrophy during non-weight bearing. Because loaded eccentric contractions occur during normal daily activity but are absent during non-weight bearing, this investigation tested whether eccentric resistance training could prevent soleus muscle atrophy during non-weight bearing. Adult female rats were randomly assigned to either weight bearing +/- intramuscular electrodes or non-weight bearing +/- intramuscular electrodes groups. Electrically stimulated maximal eccentric contractions (4 sets of 6 repetitions at approximately 0.2 fiber lengths/s, 128 degrees range of motion) were performed on anesthetized animals at 48-h intervals during the 10-day experiment. Non-weight bearing significantly reduced soleus muscle wet weight (28-31%) and noncollagenous protein content (30-31%) compared with controls. Eccentric exercise training during non-weight bearing attenuated but did not prevent the loss of soleus muscle wet weight and noncollagenous protein by 77 and 44%, respectively. The potential of eccentric exercise training as an effective and highly efficient counter-measure to non-weight-bearing atrophy is demonstrated in the 44% attenuation of soleus muscle noncollagenous protein loss by eccentric exercise during only 0.035% of the total non-weight-bearing time period.
尽管已经测试了各种运动模式，但没有一种能在非负重期间完全防止肌肉萎缩。由于在正常日常活动中会出现负重离心收缩，而在非负重期间则不存在，因此本研究测试了离心阻力训练是否能在非负重期间防止比目鱼肌萎缩。成年雌性大鼠被随机分为负重 +/- 肌内电极组或非负重 +/- 肌内电极组。在为期10天的实验中，每隔48小时对麻醉的动物进行电刺激最大离心收缩（4组，每组6次重复，速度约为0.2纤维长度/秒，运动范围为128度）。与对照组相比，非负重显著降低了比目鱼肌的湿重（28 - 31%）和非胶原蛋白含量（30 - 31%）。非负重期间的离心运动训练分别使比目鱼肌湿重和非胶原蛋白的损失减少了77%和44%，但并未阻止这种损失。在仅占非负重总时长0.035%的时间内进行离心运动，比目鱼肌非胶原蛋白损失减少44%，这证明了离心运动训练作为一种有效且高效的对抗非负重萎缩措施的潜力。
