Residual force enhancement is attenuated for quick stretch conditions
Residual force enhancement is attenuated for quick stretch conditions
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对于快速拉伸条件，残余力增强会减弱
DOI：
10.1016/j.jbiomech.2022.111076
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发表时间：
2022
影响因子：
2.4
通讯作者：
Herzog Walter
中科院分区：
文献类型：
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作者：
Fukutani Atsuki;Herzog Walter
人们普遍认为，残余力增强的大小不受拉伸速度的影响。然而，我们最近发现，当拉伸速度过大时，猫比目鱼肌在原位的残余力增强的幅度减弱或消失。因此，本研究的目的是通过在去皮的兔腰肌和比目鱼肌纤维中进行非常快速的拉伸来扩展知识。带皮的腰肌（N = 17）或比目鱼肌（N = 13）肌纤维在肌节平均长度为2.7 μm时等长激活，然后在0.5或500 ms内主动拉伸至肌节平均长度为3.0 μm，然后在该长度处等长收缩。此外，在平均肌节长度为3.0 μm时进行纯等长参考收缩，以计算两种拉伸速度下残余力增强的幅度。0.5 ms牵拉（腰大肌101.5 ± 5.6%，比目鱼肌101.5 ± 2.3%）和500 ms牵拉（腰大肌106.2 ± 5.9%，比目鱼肌106.8 ± 5.1%）之间的残余力增强幅度存在显著差异，而肌肉之间的残余力增强幅度没有显著差异。与我们先前的发现一致，当拉伸速度非常大时，残余力增强的幅度可以变化。这一发现有助于阐明诱导剩余力增强的关键机制，并解释以前研究中获得的矛盾结果。
It is generally accepted that the magnitude of residual force enhancement is not affected by stretching velocity. However, we recently found that when the stretching velocity was too large, the magnitude of residual force enhancement was attenuated or vanished in cat soleus muscle in situ. Therefore, the purpose of this study was to extend the knowledge by conducting very quick stretches in skinned rabbit psoas and soleus muscle fibers. Skinned psoas (N = 17) or soleus (N = 13) muscle fibers were activated isometrically at an average sarcomere length of 2.7 μm, and then, actively stretched to an average sarcomere length of 3.0 μm in 0.5 or 500 ms, followed by an isometric contraction at that length. In addition, a purely isometric reference contraction was conducted at an average sarcomere length of 3.0 μm to calculate the magnitude of residual force enhancement for both stretch velocities. The magnitude of residual force enhancement was significantly different between 0.5 ms stretch (101.5 ± 5.6% for psoas, and 101.5 ± 2.3% for soleus) and 500 ms stretch (106.2 ± 5.9% for psoas, and 106.8 ± 5.1% for soleus) while the magnitude of residual force enhancement was not significantly different between muscles. In line with our previous finding, the magnitude of residual force enhancement can vary when the stretch velocity is very large. This finding can contribute to clarify the key mechanism for inducing residual force enhancement and to explain contradicting results obtained in previous studies.