Geckos are exceptional at terrestrial locomotion and can move on diverse terrains and surface orientations. Geckos employ cyclical lateral bending of their flexible trunk and tail to coordinate their limb movements. In this study, using an optical motion capture system, we measured the kinematics of this lateral undulation pattern of geckos (Gekko gecko) at increasing locomotion velocity on horizontal plane, 45° inclined plane and vertical plane, respectively. We observed that geckos increased their stride frequency and stride length to increase the locomotion velocity; the effect of stride frequency on the locomotion velocity was greater than that of stride length. With increasing speed, the lateral undulation pattern changed from standing to travelling. The waveform of the trunk movement appeared as single-peak curves in a standing wave at low speeds and was propagated from head to tail in a travelling wave at high speeds. Analysis of the anatomical characteristics and axial angular kinematics of the two patterns revealed that the lateral undulation pattern results from girdle rotation and axial muscle activity. Thus, the travelling wave is the combined effect of the lateral trunk bending and deflection of the body relative to the motion direction.

中文翻译：

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壁虎攀爬运动学：横向起伏模式

壁虎在陆地运动方面非常出色，可以在不同的地形和表面方向上移动。壁虎利用它们灵活的躯干和尾巴的周期性横向弯曲来协调它们的四肢运动。在这项研究中，我们使用光学运动捕捉系统，分别测量了壁虎 (Gekko gecko) 在水平面、45° 斜面和垂直面上增加运动速度时的这种横向波动模式的运动学。我们观察到壁虎会增加步频和步幅以增加运动速度；步频对运动速度的影响大于步长。随着速度的增加，横向波动模式由站立变为行走。躯干运动的波形在低速时表现为驻波中的单峰曲线，在高速时以行波形式从头到尾传播。对两种模式的解剖特征和轴向角度运动学的分析表明，横向波动模式是由腰带旋转和轴向肌肉活动引起的。因此，行波是躯干侧向弯曲和身体相对于运动方向偏转的综合效应。