Biomechanics of locomotion in Asian elephants
Biomechanics of locomotion in Asian elephants
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DOI：
10.1242/jeb.035436
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发表时间：
2010-03-01
影响因子：
2.8
通讯作者：
Heglund, N. C.
中科院分区：
文献类型：
--
作者：
Genin, J. J.;Willems, P. A.;Heglund, N. C.
大象是现存最大的陆生动物，体重可达五吨，肩高可达三米。这些特殊的尺寸提供了某些优点（例如，运动的特定质量能量成本降低），但也有缺点（例如，力与身体体积成正比，而支撑组织强度取决于其横截面积，这使得大象比小型动物相对更脆弱）。为了更好地了解体型如何影响步态力学，我们利用力平台对 34 头亚洲象 (Elephas maximus) 在 0.4-5.0 m s(-1) 的整个速度范围内的质心 (COM) 运动进行了研究。维持 COM 每单位距离运动所需的质量比机械功类似于 0.2 J kg(-1) m(-1)（约为其他动物平均值的 1/3，尺寸范围从 35 克袋鼠到 70 公斤人类）。在低速时，COM 的动能和势能之间的类似钟摆的交换减少了这项功，在 1.4 m s(-1) 时最大能量交换约为 60%。在高速行驶时，大象使用弹跳机制，尽管没有空中阶段，但 COM 的动能和势能之间几乎没有交换。大象在提高速度的同时，将 COM 的垂直摆动从约 3 厘米减少到 1 厘米。
Elephants are the biggest living terrestrial animal, weighing up to five tons and measuring up to three metres at the withers. These exceptional dimensions provide certain advantages (e.g. the mass-specific energetic cost of locomotion is decreased) but also disadvantages (e.g. forces are proportional to body volume while supportive tissue strength depends on their cross-sectional area, which makes elephants relatively more fragile than smaller animals). In order to understand better how body size affects gait mechanics the movement of the centre of mass (COM) of 34 Asian elephants (Elephas maximus) was studied over their entire speed range of 0.4-5.0 m s(-1) with force platforms. The mass-specific mechanical work required to maintain the movements of the COM per unit distance is similar to 0.2 J kg(-1) m(-1) (about 1/3 of the average of other animals ranging in size from a 35 g kangaroo rat to a 70 kg human). At low speeds this work is reduced by a pendulum-like exchange between the kinetic and potential energies of the COM, with a maximum energy exchange of similar to 60% at 1.4 m s(-1). At high speeds, elephants use a bouncing mechanism with little exchange between kinetic and potential energies of the COM, although without an aerial phase. Elephants increase speed while reducing the vertical oscillation of the COM from about 3 cm to 1 cm.