Department of Evolutionary Anthropology, Duke University, Durham, North Carolina.
UMR 7179 C.N.R.S., M.N.H.N. Département Adaptations du Vivant, Muséum National d'Histoire Naturelle, Paris, France.
Am J Phys Anthropol. 2018 Nov;167(3):602-614. doi: 10.1002/ajpa.23688. Epub 2018 Aug 29.
In this study, we explore whether ground reaction forces recorded during horizontal walking co-vary with the shape of the long bones of the forelimb in strepsirrhines. To do so, we quantify (1) the shape of the shaft and articular surfaces of each long bone of the forelimb, (2) the peak vertical, mediolateral, and horizontal ground reaction forces applied by the forelimb during arboreal locomotion, and (3) the relationship between the shape of the forelimb and peak forces.
Geometric morphometric approaches were used to quantify the shape of the bones. Kinetic data were collected during horizontal arboreal walking in eight species of strepsirrhines that show variation in habitual substrate use and morphology of the forelimb. These data were then used to explore the links between locomotor behavior, morphology, and mechanics using co-variation analyses in a phylogenetic framework.
Our results show significant differences between slow quadrupedal climbers (lorises), vertical clinger and leapers (sifaka), and active arboreal quadrupeds (ring-tailed lemur, ruffed lemur) in both ground reaction forces and the shape of the long bones of the forelimb, with the propulsive and medially directed peak forces having the highest impact on the shape of the humerus. Co-variation between long bone shape and ground reaction forces was detected in both the humerus and ulna even when accounting for differences in body mass.
These results demonstrate the importance of considering limb-loading beyond just peak vertical force, or substrate reaction force. A re-evaluation of osseous morphology and functional interpretations is necessary in light of these findings.
在本研究中，我们探索了在树栖食虫目动物中，水平行走时记录的地面反作用力是否与前肢长骨的形状有关。为此，我们量化了（1）前肢长骨的轴和关节表面的形状，（2）前肢在树栖运动中施加的垂直峰值、内外侧峰值和水平峰值地面反作用力，以及（3）前肢形状与峰值力之间的关系。
使用几何形态测量方法来量化骨骼的形状。在 8 种具有不同习惯性基质使用和前肢形态的树栖食虫目动物中进行水平树栖行走时，收集了运动学数据。然后，我们使用系统发育框架中的共变分析来探索运动行为、形态和力学之间的联系。
我们的结果表明，在地面反作用力和前肢长骨的形状方面，慢四足攀爬者（懒猴）、垂直攀爬和跳跃者（狐猴）以及活跃的树栖四足动物（环尾狐猴、皱领狐猴）之间存在显著差异，推动和内侧定向的峰值力对肱骨的形状影响最大。即使考虑到体重差异，在肱骨和尺骨中都检测到了长骨形状和地面反作用力之间的共变关系。
这些结果表明，在评估骨骼形态和功能解释时，除了垂直峰值力或基质反作用力外，还需要考虑肢体受力。
