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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >Integration of biomechanical compliance, leverage, and power in elephant limbs
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Integration of biomechanical compliance, leverage, and power in elephant limbs

机译：整合大象肢体的生物力学顺应性，杠杆作用和力量

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摘要

The structure and motion of elephant limbs are unusual compared with those of other animals. Elephants stand and move with straighter limbs (at least when walking), and have limited speed and gait. We devised novel experiments to examine how the limbs of elephants support and propel their mass and to explore the factors that may constrain locomotor performance in these largest of living land animals. We demonstrate that elephant limbs are remarkably compliant even in walking, which maintains low peak forces. Dogma defines elephant limbs as extremely "columnar" for effective weight support, but we demonstrate that limb effective mechanical advantage (EMA) is roughly one-third of that predicted for their size. EMA in elephants is actually smaller than that in horses, which are only one-tenth their mass; it is comparable to human limb values. EMA drops sharply with speed in elephants, as it does in humans. Muscle forces therefore must increase as the limbs become more flexed, and we show how this flexion translates to greater volumes of muscle recruited for locomotion and hence metabolic cost. Surprisingly, elephants use their forelimbs and hindlimbs in similar braking and propulsive roles, not dividing these functions among limbs as was previously assumed or as in other quadrupeds. Thus, their limb function is analogous to four-wheel-drive vehicles. To achieve the observed limb compliance and low peak forces, elephants synchronize their limb dynamics in the vertical direction, but incur considerable mechanical costs from limbs working against each other horizontally.
机译：与其他动物相比，大象肢体的结构和运动是不寻常的。大象站立和移动时笔直的腿（至少在行走时），速度和步态有限。我们设计了新颖的实验来检查大象的肢体如何支撑和推动大象的体重，并探索可能限制这些最大的陆地动物运动能力的因素。我们证明，即使在行走时，大象肢体也非常顺从，从而保持了较低的峰值力。教条将大象的四肢定义为有效支撑体重的“支柱”，但是我们证明了四肢的有效机械优势（EMA）约为其预计大小的三分之一。大象的EMA实际上比马的小，只有它们的质量的十分之一；它可与人的肢体价值相媲美。象人类一样，大象中的EMA也会急剧下降。因此，当四肢变得更加弯曲时，肌肉力量必须增加，并且我们展示了这种弯曲如何转化为招募更多的用于运动的肌肉，并因此而增加了代谢成本。出人意料的是，大象将它们的前肢和后肢以类似的制动和推进作用使用，而不是像以前所假定的那样或在其他四足动物中将这些功能分配在四肢之间。因此，它们的肢体功能类似于四轮驱动车辆。为了达到观察到的肢体顺应性和较低的峰值力，大象在垂直方向上同步了它们的肢体动力学，但是由于肢体在水平方向上互相作用而产生了可观的机械成本。

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  • 作者

    Lei Ren; Charlotte E. Miller; Richard Lair; John R. Hutchinson;

  • 作者单位

    Structure and Motion Laboratory, The Royal Veterinary College, London NW1 0TU, United Kingdom School of Mechanical, Aerospace and Civil Engineering, University of Manchester, Manchester M60 1QD, United Kingdom;

    Structure and Motion Laboratory, The Royal Veterinary College, London NW1 0TU, United Kingdom;

    National Elephant Institute, Thai Elephant Conservation Center, Lampang 52000, Thailand;

    Structure and Motion Laboratory, The Royal Veterinary College, London NW1 0TU, United Kingdom;

  • 收录信息 美国《科学引文索引》(SCI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    dynamics; Proboscidea; gait; locomotion; scaling;

    机译：动力学;象鼻虫步态;运动缩放;

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