Mechanics of locomotion in lizards.
Mechanics of locomotion in lizards.
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发表时间：
1997-08
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通讯作者：
C. T. Farley;KO T.CHRISTINE
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作者：
C. T. Farley;KO T.CHRISTINE
在每一步的运动中，落叶松的躯干都会向侧面弯曲，因此，它们的运动似乎与哺乳动物的运动有着根本的不同。本研究的目的是确定蜥蜴是否使用相同的两个基本步态作为其他腿的动物，或者他们是否使用一个机械独特的步态，由于躯干侧向弯曲。力平台和运动学测量显示，两种蜥蜴，Coleonyx variegatus和Eumeces skiltonianus，使用两个基本的步态类似于哺乳动物的步行和小跑步态。在这两种步态中，由于质心的横向运动引起的动能波动小于总外部机械能波动的5%。在行走步态中，两个物种都像倒立的双足一样在站立的四肢上跳跃。质心的动能和重力势能的波动大约有180度的相位差。蜥蜴保存多达51%的外部机械能所需的运动由倒立摆机制。这两个物种也使用弹跳步态，类似于哺乳动物小跑，其中动能和质心的重力势能的波动几乎完全相同。旅行1 m（1.5 J kg-1）所需的特定质量外部机械功与其他腿动物相似。因此，尽管蜥蜴的躯干有明显的侧向弯曲，但其运动机制与其他有腿动物的运动机制相似。
Lizards bend their trunks laterally with each step of locomotion and, as a result, their locomotion appears to be fundamentally different from mammalian locomotion. The goal of the present study was to determine whether lizards use the same two basic gaits as other legged animals or whether they use a mechanically unique gait due to lateral trunk bending. Force platform and kinematic measurements revealed that two species of lizards, Coleonyx variegatus and Eumeces skiltonianus, used two basic gaits similar to mammalian walking and trotting gaits. In both gaits, the kinetic energy fluctuations due to lateral movements of the center of mass were less than 5% of the total external mechanical energy fluctuations. In the walking gait, both species vaulted over their stance limbs like inverted pendulums. The fluctuations in kinetic energy and gravitational potential energy of the center of mass were approximately 180 degrees out of phase. The lizards conserved as much as 51% of the external mechanical energy required for locomotion by the inverted pendulum mechanism. Both species also used a bouncing gait, similar to mammalian trotting, in which the fluctuations in kinetic energy and gravitational potential energy of the center of mass were nearly exactly in phase. The mass-specific external mechanical work required to travel 1 m (1.5 J kg-1) was similar to that for other legged animals. Thus, in spite of marked lateral bending of the trunk, the mechanics of lizard locomotion is similar to the mechanics of locomotion in other legged animals.