Muscle fibre conduction velocity varies in opposite directions after short- vs. long-duration muscle contractions
Muscle fibre conduction velocity varies in opposite directions after short- vs. long-duration muscle contractions
复制标题
短时与长时肌肉收缩后，肌纤维传导速度沿相反方向变化
DOI：
10.1007/s00421-021-04613-8
复制
发表时间：
2021
影响因子：
3
通讯作者：
N. Place
中科院分区：
文献类型：
--
作者：
J. Rodríguez;N. Place
肌肉收缩对肌纤维传导速度的影响通常是针对特定持续时间和强度的收缩进行研究，大多数研究集中在长时间收缩期间/之后传导速度的下降。在此，我们对不同持续时间和强度的自发性收缩后传导速度的变化进行了系统的分析。方法在膝关节伸肌等距最大自主收缩（MVCs） 1、3、6、10、30和60秒前后，以及在MVC力的10、30、50、70和90%的短暂（3 s）收缩后，测量股外侧肌的传导速度。在每次宫缩后的10分钟内测量。结果(1)短时间（≤10 s） MVCs后（1 s）传导速度立即升高（12±2%，P< 0.05），然后迅速（15 s内）恢复到对照水平；(2) 3-s、6-s和10-s MVCs后传导速度的增加幅度相似（P < 0.05）；(3)短暂收缩后传导速度的增加幅度随着收缩强度的增大而增大（在MVC力的10、30、50、70和90%时，传导速度分别增加了4.6、7.7、11.4、14.8和15.2%）；(4) 30s后传导速度没有立即下降（P < 0.05）；(5)长时间（≥30 s） mvc后1 s传导速度未达到最小。结论短暂（≤10 s）的肌肉收缩可引起传导速度的短期升高，持续时间为15 s，而长时间（≥30 s）的肌肉收缩可引起传导速度的长期降低，持续时间大于2 min。
IntroductionThe effects of muscle contractions on muscle fibre conduction velocity have normally been investigated for contractions of a given duration and intensity, with most studies being focused on the decline on conduction velocity during/after prolonged contractions. Herein, we perform a systematic analysis of the changes in conduction velocity after voluntary contractions of different durations and intensities.MethodsConduction velocity was estimated in thevastus lateralisbefore and after knee extensor isometric maximal voluntary contractions (MVCs) of 1, 3, 6, 10, 30 and 60 s, and after brief (3 s) contractions at 10, 30, 50, 70, and 90% of MVC force. Measurements were made during the 10-min period following each contraction.Results(1) Conduction velocity was increased immediately after (1 s) the MVCs of brief (≤ 10 s) duration (12 ± 2%,P< 0.05), and then returned rapidly (within 15 s) to control levels; (2) the extent of the increase in conduction velocity was similar after the 3-s, 6-s, and 10-s MVCs (P> 0.05); (3) the magnitude of the increase in conduction velocity after a brief contraction augmented with the intensity of the contraction (increases of 4.6, 7.7, 11.4, 14.8, and 15.2% for contractions at 10, 30, 50, 70, and 90% of MVC force, respectively); (4) conduction velocity was not decreased immediately after the 30-s MVC (P> 0.05); and (5) conduction velocity did not reach its minimum 1 s after the long (≥ 30 s) MVCs.ConclusionsBrief (≤ 10 s) muscle contractions induce a short-term increase in conduction velocity, lasting 15 s, while long (≥ 30 s) contractions produce a long-term decrease in conduction velocity, lasting more than 2 min.