School of Science and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia.
School of Biomedical Sciences, University of Queensland, St Lucia, Queensland 4072, Australia.
Biol Lett. 2021 Feb;17(2):20200612. doi: 10.1098/rsbl.2020.0612. Epub 2021 Feb 3.
Geometric scaling predicts a major challenge for legged, terrestrial locomotion. Locomotor support requirements scale identically with body mass (), while force-generation capacity should scale as it depends on muscle cross-sectional area. Mammals compensate with more upright limb postures at larger sizes, but it remains unknown how sprawling tetrapods deal with this challenge. Varanid lizards are an ideal group to address this question because they cover an enormous body size range while maintaining a similar bent-limb posture and body proportions. This study reports the scaling of ground reaction forces and duty factor for varanid lizards ranging from 7 g to 37 kg. Impulses (force×time) () and peak forces () scaled higher than expected. Duty factor scaled and was higher for the hindlimb than the forelimb. The proportion of vertical impulse to total impulse increased with body size, and impulses decreased while peak forces increased with speed.
几何缩放预测了对腿部、陆地运动的主要挑战。运动支持要求与体重（）成比例缩放，而力产生能力应该按比例缩放，因为它取决于肌肉横截面积。哺乳动物在较大体型时通过更直立的肢体姿势来补偿，但尚不清楚四足动物如何应对这一挑战。巨蜥是解决这个问题的理想群体，因为它们在保持弯曲肢体姿势和身体比例相似的情况下，体型范围非常广泛。本研究报告了从 7 克到 37 公斤的巨蜥的地面反作用力和作用系数的缩放。冲量（力×时间）（）和峰值力（）的缩放高于预期。作用系数按比例缩放，后肢比前肢高。垂直冲量与总冲量的比例随体型增加而增加，而冲量随速度增加而减少，峰值力随速度增加而增加。
