Mechanical properties of the gastrocnemius aponeurosis in wild turkeys
Mechanical properties of the gastrocnemius aponeurosis in wild turkeys
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DOI：
10.1093/icb/icp006
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发表时间：
2009-07-01
影响因子：
2.6
通讯作者：
Roberts, Thomas J.
中科院分区：
文献类型：
--
作者：
Azizi, Emanuel;Halenda, Gregory M.;Roberts, Thomas J.
在许多肌肉中，肌腱结构包括肌外游离肌腱和片状腱膜。在游离肌腱和腱膜中，胶原束主要沿着肌肉的作用线纵向定向。通常假设该轴代表这些结构的载荷方向。这种假设对于自由肌腱来说是有根据的，但是腱膜经历更复杂的加载机制。与自由肌腱不同，腱膜围绕肌腹的大部分，因此当收缩肌肉凸起以保持恒定体积时，腱膜与肌肉的作用线平行（纵向）和垂直（横向）加载。鉴于这种双轴加载模式，了解腱膜纵向和横向的机械特性至关重要。在本研究中，我们对来自野生火鸡腓肠肌外侧腱膜的分离组织样本进行单轴测试，以确定纵向（沿肌肉作用线）和横向（与作用线正交）加载的样本的机械特性。我们发现腱膜纵向的杨氏模量明显高于横向的杨氏模量。我们的结果还表明，腱膜在纵向和横向上都可以充当高效弹簧，几乎不会因滞后而损失能量。我们还测试了腱膜的失效特性，以量化这些结构在肌肉力量产生过程中运行的可能安全系数。这些结果为理解腱膜作为双轴加载生物弹簧的机械功能提供了重要基础。
In many muscles, the tendinous structures include both an extramuscular free tendon as well as a sheet-like aponeurosis. In both free tendons and aponeuroses the collagen fascicles are oriented primarily longitudinally, along the muscle's line of action. It is generally assumed that this axis represents the direction of loading for these structures. This assumption is well founded for free tendons, but aponeuroses undergo a more complex loading regime. Unlike free tendons, aponeuroses surround a substantial portion of the muscle belly and are therefore loaded both parallel (longitudinal) and perpendicular (transverse) to a muscle's line of action when contracting muscles bulge to maintain a constant volume. Given this biaxial loading pattern, it is critical to understand the mechanical properties of aponeuroses in both the longitudinal and transverse directions. In this study, we use uniaxial testing of isolated tissue samples from the aponeurosis of the lateral gastrocnemius of wild turkeys to determine mechanical properties of samples loaded longitudinally (along the muscle's line of action) and transversely (orthogonal to the line of action). We find that the aponeurosis has a significantly higher Young's modulus in the longitudinal than in the transverse direction. Our results also show that aponeuroses can behave as efficient springs in both the longitudinal and transverse directions, losing little energy to hysteresis. We also test the failure properties of aponeuroses to quantify the likely safety factor with which these structures operate during muscular force production. These results provide an essential foundation for understanding the mechanical function of aponeuroses as biaxially loaded biological springs.