Sex differences in the fatigability of arm muscles depends on absolute force during isometric contractions
Sex differences in the fatigability of arm muscles depends on absolute force during isometric contractions
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DOI：
10.1152/jappl.2001.91.6.2686
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发表时间：
2001-12-01
影响因子：
3.3
通讯作者：
Enoka, RM
中科院分区：
文献类型：
--
作者：
Hunter, SK;Enoka, RM
在低强度到中等强度的收缩中，女性的耐力比男性要长。该研究的目的是：1)确定次最大等长收缩的绝对目标力和耐力时间之间的关系；2)比较男性（26.3 +/- 1.1 (SE) yr）和女性（27.5 +/- 2.3 yr）在肘关节屈肌疲劳收缩时的压力反应和肌肉激活模式。男性的最大自主收缩力（MVC）更大（393 +/- 23比177 +/- 7 N），这意味着男性的平均目标力（MVC的20%）更大（79.7 +/- 6.5比36.7 +/- 2.0 N）。女性的疲劳收缩耐力时间长118% （1806 +/- 239 vs. 829 +/- 94）。男性（31 +/- 2%）和女性（30 +/- 2%）精疲力竭时肘关节屈肌矫正肌电图（%MVC）的平均值相似。相比之下，女性疲劳时的心率和平均动脉压（MAP）较低（分别为94 +/- 6 vs 111 +/- 7次/分，121 +/- 5 vs 150 +/- 6 mmHg）。疲劳收缩过程中目标力和MAP变化与耐力时间呈指数相关(r(2) = 0.68和r(2) = 0.64)， MAP变化与目标力呈线性相关（r(2) = 0.51）。当进行次最大收缩时，男性和女性的疲劳程度差异与绝对收缩强度有关，并受到远端肌肉激活机制的限制。
Women are capable of longer endurance times compared with men for contractions performed at low to moderate intensities. The purpose of the study was 1) to determine the relation between the absolute target force and endurance time for a submaximal isometric contraction and 2) to compare the pressor response and muscle activation patterns of men [26.3 +/- 1.1 (SE) yr] and women (27.5 +/- 2.3 yr) during a fatiguing contraction performed with the elbow flexor muscles. Maximal voluntary contraction (MVC) force was greater for men (393 +/- 23 vs. 177 +/- 7 N), which meant that the average target force (20% of MVC) was greater for men (79.7 +/- 6.5 vs. 36.7 +/- 2.0 N). The endurance time for the fatiguing contractions was 118% longer for women (1,806 +/- 239 vs. 829 +/- 94 s). The average of the rectified electromyogram (%MVC) for the elbow flexor muscles at exhaustion was similar for men (31 +/- 2%) and women (30 +/- 2%). In contrast, the heart rate and mean arterial pressure (MAP) were less at exhaustion for women (94 +/- 6 vs. 111 +/- 7 beats/min and 121 +/- 5 vs. 150 +/- 6 mmHg, respectively). The target force and change in MAP during the fatiguing contraction were exponentially related to endurance time (r(2) = 0.68 and r(2) = 0.64, respectively), whereas the change in MAP was linearly related to target force (r(2) = 0.51). The difference in fatigability of men and women when performing a submaximal contraction was related to the absolute contraction intensity and was limited by mechanisms that were distal to the activation of muscle.