Men are more fatigable than strength-matched women when performing intermittent submaximal contractions
Men are more fatigable than strength-matched women when performing intermittent submaximal contractions
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DOI：
10.1152/japplphysiol.01342.2003
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发表时间：
2004-06-01
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;Critchlow, A;Enoka, RM
本研究的目的是比较力量匹配的男性和女性肘部屈肌进行一系列间歇性次极大收缩的时间到任务失败（n = 20, 18-34岁）。疲劳任务包括以最大自主收缩（MVC）扭矩的50%进行等距收缩（收缩6秒，休息4秒）。男性和女性的MVC扭矩相似[64.8 +/- 9.2 (SD) vs. 62.2 +/- 7.9 N.m；P[0.05]。然而，尽管扭矩水平相似，但女性的任务失败时间更长（1,408 +/- 1,133 vs. 513 +/- 194秒；P < 0.05）。男性和女性的平均动脉压、心率和感知劳累等级的开始和结束值相似，但女性的增长率较低。女性肘部屈肌的矫直肌电图（AEMG； %峰值MVC）的平均增长率较低：在任务失败时，男性的AEMG高于女性（72±28比50±21%；P < 0.05），尽管疲劳收缩开始时的AEMG值相似（32 +/- 9比36 +/- 13%）。这些结果表明，对于肘关节屈肌进行的间歇性收缩，1)完成任务失败的时间上的性别差异不能用男性和女性的绝对力量来解释，而是涉及到在灌注条件下存在的另一种机制，2)男性需要更快地增加下降驱动以保持相似的扭矩。
The purpose of this study was to compare the time to task failure for a series of intermittent submaximal contractions performed with the elbow flexor muscles by men and women who were matched for strength (n = 20, 18-34 yr). The fatigue task comprised isometric contractions at 50% of maximal voluntary contraction (MVC) torque (6-s contraction, 4-s rest). The MVC torque was similar for the men and women [64.8 +/- 9.2 (SD) vs. 62.2 +/- 7.9 N.m; P > 0.05]. However, the time to task failure was longer for the women (1,408 +/- 1,133 vs. 513 +/- 194 s; P < 0.05), despite the similar torque levels. The mean arterial pressure, heart rate, and rating of perceived exertion started and ended at similar values for the men and women, but the rate of increase was less for the women. The rate of increase in the average of the rectified electromyogram (AEMG; % peak MVC) for the elbow flexor muscles was less for the women: the AEMG was greater for the men compared with the women at task failure (72 ± 28 vs. 50 ± 21%; P < 0.05), despite similar AEMG values at the start of the fatiguing contraction (32 +/- 9 vs. 36 +/- 13%). These results indicate that for intermittent contractions performed with the elbow flexor muscles 1) the sex difference in time to task failure was not explained by the absolute strength of the men and women, but involved another mechanism that is present during perfused conditions, and 2) men required a more rapid increase in descending drive to maintain a similar torque.