MORPHOLOGY AND ENZYMATIC CAPACITY IN ARM AND LEG MUSCLES IN 78-81 YEAR OLD MEN AND WOMEN
MORPHOLOGY AND ENZYMATIC CAPACITY IN ARM AND LEG MUSCLES IN 78-81 YEAR OLD MEN AND WOMEN
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DOI：
10.1111/j.1748-1716.1982.tb07054.x
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发表时间：
1982-01-01
期刊：
影响因子：
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通讯作者：
SALTIN, B
中科院分区：
文献类型：
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作者：
GRIMBY, G;DANNESKIOLDSAMSOE, B;SALTIN, B
对12名男性和12名女性78-81岁进行了研究，对右侧股外侧肌和肱二头肌进行了肌肉活检，并测量了膝关节伸展的等长和等速力量以及肘关节屈曲的等长力量。还进行了自行车测力计，测定次最大（50 W）和最大工作负荷下的心率和O2摄取量。体细胞质量通过测量全身K来估计。肌肉纤维组成方面的慢颤（ST = I型）和快颤（FT = II型）纤维没有性别和年轻的受试者从人口研究中得出的差异。股外侧肌的平均纤维面积分别为4.7和3.3 × 10 - 5。男性和女性分别为103 μ m2。这是从不到10%到30%的值发现久坐不动的年轻人。下降的主要是FT纤维，尤其是FTb纤维。相比之下，肱二头肌没有显示出任何匹配的纤维尺寸减小。萎缩纤维的数量是高的，所以是封闭的纤维和区域与类型分组（ST纤维）的频率，表明去神经再支配。这种异常在年轻时很少见。相关性分析表明，随着年龄的增长，只有一小部分的体细胞质量的减少可以解释为减少纤维面积和减少与年龄的两种纤维类型的肌纤维的数量必须假设。肌肉力量与平均肌纤维和FT面积呈正相关。比较骨骼肌形态的现有研究结果与那些在年轻的年龄组，很明显，在第八个十年的生活发生重大变化。对需氧和厌氧酶活性以及肌肉毛细血管供应的测量表明，维持了与年轻年龄组相当的水平。因此，工作业绩随年龄增长而下降的原因可能是数量上的变化，而不是质量上的变化。
Twelve men and twelve women 78-81 years of age were studied with muscle biopsies from the right vastus lateralis and biceps brachii and with measurements of isometric and isokinetic strength for knee-extension and isometric strength for elbow-flexion. Bicycle ergometry with determination of heart rate and O2 uptake at submaximal (50 W) and maximal work loads was also performed. Body cell mass was estimated from measurements of total body K. Muscle fiber composition with respect to slow twitch (ST = type I) and fast twitch (FT = type II) fibers did not differ between the sexes and the younger subjects drawn from population studies. The mean fiber areas in vastus lateralis averaged, 4.7 and 3.3 .times. 103 .mu.m2 in men and women, respectively. This is from less than 10 up to 30% of the values found in sedentary younger subjects. The decline dominated in FT fibers, especially FTb fibers. In contrast, biceps brachii did not show any matched fiber size reduction. The number of atrophic fibers was high and so was the frequency of enclosed fibers and areas with type grouping (ST fibers), indicating denervation-reinnervation. Such abnormalities are rarely seen at younger ages. Correlation analysis showed that only a minor part of the reduction in body cell mass with age could be explained by a reduction in fiber areas and that a reduction with age of the number of muscle fibers of both fiber types must be assumed. Positive correlations were observed between muscle strength and mean fiber and FT areas. Comparing the present findings of skeletal muscle morphology with those in younger age groups, it is apparent that during the 8th decade of life major changes do occur. The measurements of aerobic and anaerobic enzymatic activities and of muscle capillary supply showed that levels comparable to those of younger age groups are maintained. Thus, quantitative rather than qualitative changes may explain the reduction in work performance with age.