School of Life Sciences, Coventry University, UK.
J Gerontol A Biol Sci Med Sci. 2018 Apr 17;73(5):579-587. doi: 10.1093/gerona/glx243.
There is currently a limited amount of literature investigating the age-related changes in eccentric muscle function in vitro. The present study uniquely uses the work loop (WL) technique, to better replicate in vivo muscle function, in the assessment of the age- and muscle-specific changes in acute and sustained concentric and eccentric power and recovery. Whole soleus or extensor digitorum longus (EDL) muscles were isolated from 10-week and 78-week-old mice and acute and sustained concentric and eccentric WL power assessed. Despite an age-related increase in body and muscle mass, peak absolute power for both muscles was unaffected by age. Peak concentric power normalized to muscle mass declined significantly for each muscle, while peak normalized eccentric power declined only for soleus. Fatigue resistance and recovery for the soleus did not differ between age or contraction type. Older EDL was less resistant to concentric fatigue, but was better able to withstand sustained eccentric activity than young EDL. We have shown that age-related changes in muscle quality are more limited for eccentric function than concentric function. A greater bodily inertia is likely to further reduce in vivo locomotor performance in older animals.
目前，关于体外研究与年龄相关的离心肌肉功能变化的文献有限。本研究采用工作循环（WL）技术，更好地复制体内肌肉功能，评估急性和持续向心和离心力量以及恢复的年龄和肌肉特异性变化。从 10 周龄和 78 周龄的小鼠中分离出整个比目鱼肌或趾长伸肌（EDL），并评估急性和持续向心和离心 WL 力量。尽管与年龄相关的体重和肌肉质量增加，但两种肌肉的绝对峰值功率均不受年龄影响。每个肌肉的峰值向心功率与肌肉质量的比值显著下降，而峰值向心功率与肌肉质量的比值仅下降。比目鱼肌的疲劳抵抗力和恢复力在年龄或收缩类型之间没有差异。老年 EDL 对向心疲劳的抵抗力降低，但比年轻 EDL 更能耐受持续的离心活动。我们已经表明，与向心功能相比，离心功能的肌肉质量变化与年龄相关的变化更为有限。更大的身体惯性可能会进一步降低老年动物的体内运动表现。
