Locomotor function shapes the passive mechanical properties and operating lengths of muscle
Locomotor function shapes the passive mechanical properties and operating lengths of muscle
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DOI：
10.1098/rspb.2013.2914
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发表时间：
2014-05-22
影响因子：
4.7
通讯作者：
Azizi, E.
中科院分区：
文献类型：
--
作者：
Azizi, E.
运动肌肉通常扮演不同的角色，作为产生机械能的马达，产生力的支柱和消耗机械能的制动器。在许多脊椎动物的肌肉中，这些功能并不是相互排斥的，单个肌肉经常执行一系列机械不同的任务。这种功能的多样性模糊了肌肉运动功能与其机械特性之间的关系。我用蟾蜍跳跃作为一个模型系统来比较主要产生机械能的肌肉和主要消耗机械能的肌肉。在跳跃过程中，后肢肌肉主动缩短以产生机械能并推动动物进入空中，而在着陆过程中，前肢肌肉主动延长以消耗机械能。执行不同机械功能的肌肉作用于力-长度曲线的不同区域。这些发现表明，肌肉的活动长度可能是由力量产生和肌节稳定性之间的潜在权衡决定的。此外，后肢和前肢肌肉的被动力长度特性不同，表明被动刚度在体内起着限制肌肉运作长度的作用。这些结果通过提供肌肉运动功能与其机械特性之间的明确联系，使我们了解脊椎动物肌肉的变化。
Locomotor muscles often perform diverse roles, functioning as motors that produce mechanical energy, struts that produce force and brakes that dissipate mechanical energy. In many vertebrate muscles, these functions are not mutually exclusive and a single muscle often performs a range of mechanically diverse tasks. This functional diversity has obscured the relationship between a muscle's locomotor function and its mechanical properties. I use hopping in toads as a model system for comparing muscles that primarily produce mechanical energy with muscles that primarily dissipate mechanical energy. During hopping, hindlimb muscles undergo active shortening to produce mechanical energy and propel the animal into the air, whereas the forelimb muscles undergo active lengthening to dissipate mechanical energy during landing. Muscles performing distinct mechanical functions operate on different regions of the force-length curve. These findings suggest that a muscle's operating length may be shaped by potential trade-offs between force production and sarcomere stability. In addition, the passive force-length properties of hindlimb and forelimb muscles vary, suggesting that passive stiffness functions to restrict the muscle's operating length in vivo. These results inform our understanding of vertebrate muscle variation by providing a clear link between a muscle's locomotor function and its mechanical properties.