Activation of fast-twitch fibers assessed with twitch potentiation
Activation of fast-twitch fibers assessed with twitch potentiation
复制标题
通过抽搐增强评估快肌纤维的激活
DOI：
10.1002/mus.23290
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发表时间：
2012
期刊：
影响因子：
3.4
通讯作者：
Ishii N
中科院分区：
文献类型：
--
作者：
Sasaki K;Tomioka Y;Ishii N
简介：短暂肌肉激活后抽搐反应的增强（称为抽搐增强）已被证明在快肌纤维中比在慢肌纤维中更加明显。因此，我们通过研究其对先前收缩强度的依赖性，探索了抽搐增强作为快速收缩纤维激活的非侵入性测量的可能性。方法：在10-100%最大随意收缩（MVC）强度的6 s随意收缩之前和之后立即，用胫后神经的超大刺激诱发跖屈肌的抽搐收缩。结果：除低强度收缩（< 30%MVC）外，自主收缩引起抽搐增强，其幅度随收缩强度的增加而增加（P< 0.001）。结论：这些结果与“纤维激活的层次顺序”的概念相一致，表明肌颤增强的幅度反映了短收缩过程中快肌颤纤维的激活。肌肉神经46：218-227，2012
Introduction: The augmentation of twitch response following brief muscle activation, called twitch potentiation, has been shown to be much more pronounced in fast‐twitch than in slow‐twitch fibers. We thus explored the possibility of twitch potentiation as a noninvasive measure of fast‐twitch fiber activation, by studying its dependence on the intensity of preceding contraction.Methods: Twitch contraction of plantar flexor muscles was evoked with supramaximal stimulation of the posterior tibial nerve, before and immediately after 6‐s voluntary contractions at intensities of 10–100% of maximal voluntary contraction (MVC).Results: Except for low‐intensity contractions (< 30%MVC), voluntary contraction induced twitch potentiation, the magnitude of which increased with increasing contraction intensity (P< 0.001). The shortened contractile process was associated with the potentiation.Conclusions: These results are consistent with the concept of “hierarchical order of fiber activation”, suggesting that the magnitude of twitch potentiation reflects the activation of fast‐twitch fibers during a brief contraction. Muscle Nerve 46: 218–227, 2012