TWITCH POTENTIATION INDUCED BY STIMULATED AND VOLUNTARY ISOMETRIC CONTRACTIONS AT VARIOUS TORQUE LEVELS IN HUMAN KNEE EXTENSOR MUSCLES
TWITCH POTENTIATION INDUCED BY STIMULATED AND VOLUNTARY ISOMETRIC CONTRACTIONS AT VARIOUS TORQUE LEVELS IN HUMAN KNEE EXTENSOR MUSCLES
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DOI：
10.1002/mus.21871
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发表时间：
2011-03-01
期刊：
影响因子：
3.4
通讯作者：
Kawakami, Yasuo
中科院分区：
文献类型：
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作者：
Miyamoto, Naokazu;Yanai, Toshimasa;Kawakami, Yasuo
本研究的目的是比较人膝关节伸肌在相同强度刺激或自主收缩后抽动增强(TP)的程度。在最大自主收缩(MVC)扭矩水平的20%、40%和60%的情况下，通过80赫兹的经皮电刺激股四头肌或自主收缩，进行10S的等长伸膝。以超最大强度经皮刺激股神经，诱发抽动反应。在20%MVC扭矩水平下，刺激收缩后TP的幅度大于自主收缩后的幅度，而当收缩强度大于40%MVC时，刺激收缩引起的TP幅度小于自主收缩。我们认为，刺激和自主等长条件性收缩后TP差异的这种收缩强度依赖性是条件性收缩过程中运动单位募集模式不同的原因。肌肉神经43：360-366,2011
The purpose of this study was to compare the extent of twitch potentiation (TP) after stimulated or voluntary contractions at identical intensities for the human knee extensor muscles. Isometric knee extensions of 10 s. were performed at 20%, 40%, and 60% of maximal voluntary contraction (MVC) torque level, through percutaneous electrical stimulation of the quadriceps at 80 Hz or voluntary contraction. Twitch responses were evoked by stimulating the femoral nerve percutaneously with supramaximal intensity. The extent of TP after the stimulated contraction was greater than that after the voluntary contraction at the 20% MVC torque level, whereas a stimulated contraction induced a smaller extent of TP than did a voluntary contraction at contraction intensities higher than 40% MVC. We suggest that this contraction intensity dependence of differences in TP after stimulated and voluntary isometric conditioning contractions is responsible for differences in the recruitment pattern of motor units during the conditioning contractions. Muscle Nerve 43: 360-366, 2011