Attenuated activation of knee extensor muscles during fast contractions in older men and women.
Attenuated activation of knee extensor muscles during fast contractions in older men and women.
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DOI：
10.1007/s00421-020-04451-0
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发表时间：
2020-10
影响因子：
3
通讯作者：
Hunter SK
中科院分区：
文献类型：
--
作者：
Kwon M;Senefeld JW;Hunter SK
老年人的身体功能下降和福尔斯风险增加伴随着与年龄相关的腿部肌肉扭矩发育减少，尽管机制和潜在的性别差异尚不清楚。为了确定与年龄相关的扭矩发展减少的机械起源（神经与肌肉），我们比较了年轻和老年男性和女性之间膝伸肌电诱发和快速自主收缩期间扭矩发展（RTD）的峰值速率。单脉冲和双脉冲电刺激诱发20名年轻人膝伸肌收缩（23.0±0.8岁; 10名女性）和20名老年人（78.2±1.5岁; 10名女性），随后进行自主等长膝关节伸展收缩，扭矩发展尽可能快，与电诱发收缩期间的扭矩（10%-40%最大扭矩）相匹配。快速随意收缩时的RTD峰值比电诱发收缩时低41%（p<0.001），但老年人（44%）比年轻人（38%，p=0.04）更低，没有性别差异。快速自主收缩期间的峰值RTD在老年人收缩之间比年轻人收缩之间的差异更大（77%MVC 10 s-1 vs. 47%MVC 10 s-1，p<0.001）。此外，老年女性比老年男性表现出更大的变异性（81%MVC-1 vs. 72%MVC-1，p=0.04），在年轻人中没有性别相关的差异。老年人在自愿收缩期间的RTD比年轻人更慢，变化更大，特别是老年妇女。电诱发RTD的有限年龄相关差异表明，老年男性和女性膝伸肌扭矩发展较慢的主要机制涉及神经激活减少。
Reduced physical function and increased risk of falls in older adults are accompanied by age-related reductions in torque development of leg muscles, although the mechanisms and potential sex differences are not understood. To determine the mechanistic origins (neural vs. muscular) for the age-related reduction in torque development, we compared the peak rates of torque development (RTD) during electrically-evoked and fast voluntary contractions of the knee extensors between young and older men and women. Sets of single- and double-pulse electrical stimulations evoked contractions of the knee extensor muscles in 20 young (23.0±0.8 years; 10 women) and 20 older adults (78.2±1.5 years; 10 women), followed by voluntary isometric knee extension contractions with torque development as fast as possible that matched the torque during electrically-evoked contraction (10%–40% maximal torque). Peak RTD during fast-voluntary contractions was 41% less than electrically-evoked contractions (p<0.001), but more so for older adults (44%) than young (38%, p=0.04), with no sex differences. Peak RTD during fast-voluntary contractions was more variable between contractions for the older than young adults (77%MVC∙s−1 vs. 47%MVC∙s−1, p<0.001). Additionally, older women exhibited greater variability than older men (81%MVCs−1 vs. 72%MVCs−1, p=0.04) with no sex-related differences within the young adults. Older adults had slower and more variable RTD during voluntary contractions than young adults, particularly older women. The limited age-related differences in electrically-evoked RTD suggest the primary mechanism for the slower torque development of the knee extensor muscles in older men and women involve reduced neural activation.
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影响因子：
3.3
作者：
Hassanlouei, Hamidollah;Sundberg, Christopher W.;Hunter, Sandra K.
通讯作者：
Hunter, Sandra K.
影响因子：
5.5
作者：
Del Vecchio, Alessandro;Casolo, Andrea;Farina, Dario
通讯作者：
Farina, Dario
影响因子：
3
作者：
Izquierdo, M;Aguado, X;Häkkinen, K
通讯作者：
Häkkinen, K
影响因子：
3
作者：
Baudry, Stephane;Klass, Malgorzata;Duchateau, Jacques
通讯作者：
Duchateau, Jacques
影响因子：
3.3
作者：
Hunter, Sandra K.;Todd, Gabrielle;Taylor, Janet L.
通讯作者：
Taylor, Janet L.