Reduced strength after passive stretch of the human plantarflexors
Reduced strength after passive stretch of the human plantarflexors
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DOI：
10.1152/jappl.2000.89.3.1179
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发表时间：
2000-09-01
影响因子：
3.3
通讯作者：
MacDougall, JD
中科院分区：
文献类型：
--
作者：
Fowles, JR;Sale, DG;MacDougall, JD
本研究的目的是评估人类受试者在急性最大耐受被动拉伸（PSmax）后的力量表现。10名年轻人（6名男性和4名女性）接受了30分钟的周期性PSmax（13次拉伸，每次135 s，超过33分钟）和类似的对照期（Con），踝关节跖屈肌没有拉伸。等长肌力测量与Pre相比，最大自主收缩在PSmax或Con后5 min（28%）和5 min（21%），15 min（13%），PSmax后30、45、60 min分别为12%、10%、9%（P < 0.05）。运动单位激活和肌电图显着抑制后PSmax，但已恢复15分钟。一个额外的测试试验证实，扭矩关节角度的关系可能已经暂时改变，但在后。这些数据表明，长时间拉伸的单一肌肉减少自愿的力量长达1小时后，拉伸作为受损的激活和收缩力在早期阶段的赤字和受损的收缩力在整个期间的赤字。
The purpose of this study was to assess strength performance after an acute bout of maximally tolerable passive stretch (PSmax) in human subjects. Ten young adults (6 men and 4 women) underwent 30 min of cyclical PSmax (13 stretches of 135 s each over 33 min) and a similar control period (Con) of no stretch of the ankle plantarflexors. Measures of isometric strength (maximal voluntary contraction), with twitch interpolation and electromyography, and twitch characteristics were assessed before (Pre), immediately after (Post), and at 5, 15, 30, 45, and 60 min after PSmax or Con. Compared with Pre, maximal voluntary contraction was decreased at Post (28%) and at 5 (21%), 15 (13%), 30 (12%), 45 (10%), and 60 (9%) min after PSmax (P < 0.05). Motor unit activation and electromyogram were significantly depressed after PSmax but had recovered by 15 min. An additional testing trial confirmed that the torque-joint angle relation may have been temporarily altered, but at Post only. These data indicate that prolonged stretching of a single muscle decreases voluntary strength for up to 1 h after the stretch as a result of impaired activation and contractile force in the early phase of deficit and by impaired contractile force throughout the entire period of deficit.