Decline in isokinetic force with age: Muscle cross-sectional area and specific force
Decline in isokinetic force with age: Muscle cross-sectional area and specific force
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DOI：
10.1007/s004240050392
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发表时间：
1997-07-01
影响因子：
4.5
通讯作者：
Conley, KE
中科院分区：
文献类型：
--
作者：
Jubrias, SA;Odderson, IR;Conley, KE
随着年龄的增长，人类产生的肌肉力量 (F) 会减少。然而，老年人力量减少与肌肉横截面积（CSA）之间的关系尚未得到充分记录。我们检查了 F 和 CSA 的变化，以确定肌肉萎缩和比力 (F/CSA) 对老年人力量产生下降的相对贡献，对肌球蛋白重链 (MHC) 亚型的比例进行了表征，以评估这是否与比力随年龄的变化有关。我们测量了 57 名年龄在 23-80 岁的男性和女性等速膝关节伸展的峰值力，并使用磁共振成像来确定股四头肌的收缩面积。对股外侧肌活组织检查中获取的 MHC 亚型分析显示与比力无关，F、CSA 和 F/CSA 随着年龄的增长而下降。 65 岁至 80 岁之间发生的 39% 的力量下降中，较小的 CSA 仅占一半左右。在这个年龄段，比力每年下降约 1.5%，总共下降 21%。因此，肌肉的数量变化（萎缩）不足以解释与衰老相关的力量损失。
Humans produce less muscle force (F) as they age. However, the relationship between decreased force and muscle cross-sectional area (CSA) in older humans is not well documented. We examined changes in F and CSA to determine the relative contributions of muscle atrophy and specific force (F/CSA) to declining force production in aging humans, The proportions of myosin heavy chain (MHC) isoforms were characterized to assess whether this was related to changes in specific force with age. We measured the peak force of isokinetic knee extension in 57 males and females aged 23-80 years, and used magnetic resonance imaging to determine the contractile area of the quadriceps muscle, Analysis of MHC isoforms taken from biopsies of the vastus lateralis muscle showed no relation to specific force, F, CSA, and F/CSA decreased with age. Smaller CSA accounted for only about half of the 39% drop in force that occurred between ages 65-80 years. Specific force dropped about 1.5% per year in this age range, for a total decrease of 21%. Thus, quantitative changes in muscle (atrophy) are not sufficient to explain the strength loss associated with aging.