Fatigability and recovery of arm muscles with advanced age for dynamic and isometric contractions.
Fatigability and recovery of arm muscles with advanced age for dynamic and isometric contractions.
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DOI：
10.1016/j.exger.2012.10.006
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发表时间：
2013-02
影响因子：
3.9
通讯作者：
Hunter, Sandra K.
中科院分区：
文献类型：
--
作者：
Yoon, Tejin;Schlinder-Delap, Bonnie;Hunter, Sandra K.
这项研究确定了年龄相关机制是否会增加最大速度动态收缩期间手臂肌肉的疲劳，就像下肢发生的情况一样。我们比较了年轻人（n = 10，20.8 ± 2.7 岁）和老年男性（n = 16，73.8 ± 6.1 岁）在动态和等长姿势疲劳任务期间和恢复过程中的肘部屈肌疲劳情况。每项任务均维持至失败，同时支持相当于最大自主等长收缩 (MVIC) 扭矩 20% 的负载。经颅磁刺激 (TMS) 用于评估椎上疲劳（叠加抽搐，SIT）和肌肉松弛。对于等长任务，老年男性的失败时间比年轻人长（9.5±3.1 分钟 vs. 17.2±7.0 分钟，P=0.01），但对于动态任务则相似（6.3±2.4 分钟 vs. 6.0±2.0 分钟，P = 0.73）。老年人的初始峰值放松率比年轻人慢，并且与两项任务失败的时间较长相关（P<0.05）。肘部屈曲期间的低初始功率与等长任务和动态任务之间的最大力竭时间差异（减少）相关（r = -0.54，P = 0.015）。在两项疲劳任务后，SIT 随年龄的增长而下降，尽管 SIT 的恢复与老年人（两次训练）的 MVIC 恢复相关，但与年轻人无关。在动态疲劳任务中，老年男性的肱二头肌和肱桡肌肌电图活动（%MVIC）大于年轻人（P<0.05），但在等长任务中相似。肌肉机制和更大的相对肌肉活动（肌电图活动）解释了老年人在动态任务中与年轻人相比肘屈肌更容易疲劳。然而，与年轻男性相比，老年男性的 MVC 扭矩恢复更多地依赖于椎上疲劳的恢复。
This study determined whether age-related mechanisms can increase fatigue of arm muscles during maximal velocity dynamic contractions, as occurs in the lower limb. We compared elbow flexor fatigue of young (n=10, 20.8 ± 2.7 years) and old men (n=16, 73.8 ± 6.1 years) during and in recovery from a dynamic and an isometric postural fatiguing task. Each task was maintained until failure while supporting a load equivalent to 20% of maximal voluntary isometric contraction (MVIC) torque. Transcranial magnetic stimulation (TMS) was used to assess supraspinal fatigue (superimposed twitch, SIT) and muscle relaxation. Time to failure was longer for old men than young for the isometric task (9.5±3.1 vs. 17.2±7.0 min, P=0.01) but similar for the dynamic task (6.3±2.4 min vs. 6.0±2.0 min, P = 0.73). Initial peak rate of relaxation was slower for the old men than young, and associated with a longer time to failure for both tasks (P<0.05). Low initial power during elbow flexion was associated with the greatest difference (reduction) in time to failure between the isometric task and dynamic task (r =−0.54, P=0.015). SIT declined after both fatigue tasks similarly with age, although recovery of SIT was associated with MVIC recovery for the old (both sessions) but not the young. Biceps brachii and brachioradialis EMG activity (%MVIC) of old men were greater than young during the dynamic fatiguing task (P<0.05), but similar during the isometric task. Muscular mechanisms and greater relative muscle activity (EMG activity) explain the greater fatigue during dynamic task for the old men compared with young in elbow flexor muscles. Recovery of MVC torque however relies more on recovery of supraspinal fatigue among older men than the young men.
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影响因子：
5.5
作者：
FUGLEVAND, AJ;ZACKOWSKI, KM;ENOKA, RM
通讯作者：
ENOKA, RM
影响因子：
3.3
作者：
Dalton, Brian H.;Power, Geoffrey A.;Rice, Charles L.
通讯作者：
Rice, Charles L.
影响因子：
3.3
作者：
Hunter, Sandra K.;Todd, Gabrielle;Taylor, Janet L.
通讯作者：
Taylor, Janet L.
影响因子：
2.5
作者：
HESS, CW;MILLS, KR;MURRAY, NMF
通讯作者：
MURRAY, NMF
DOI：
10.1113/jphysiol.2012.228890
发表时间：
2012-06-01
期刊：
The Journal of physiology
影响因子：
--
作者：
Goodall S;González-Alonso J;Ali L;Ross EZ;Romer LM
通讯作者：
Romer LM