Crompton R H, Yu L, Weijie W, Günther M, Savage R
Department of Human Anatomy and Cell Biology, University of Liverpool.
J Hum Evol. 1998 Jul;35(1):55-74. doi: 10.1006/jhev.1998.0222.
It is universally accepted that the postcranial skeleton of the early hominid Australopithecus afarensis shows adaptations, or at least exaptations, towards bipedalism. However, there continues to be a debate concerning the likely form of terrestrial bipedality: whether gait was erect, like our own, or "bent-hip, bent-knee" like the bipedalism of living chimpanzees. In this study we use predictive dynamic modelling to assess the mechanical effectiveness of AL-288-1 under both hypotheses, on the basis of data on segment proportions from the literature. AL-288-1's proportions are incompatible with the kinematics of chimpanzee bipedalism, but compatible with the kinematics of either erect or "bent-hip, bent-knee" human gait. In the latter case, neither the ankle nor the knee joint would have contributed substantial mechanical work to propulsion of the body, and net energy absorption is predicted for these joints, which would have resulted in increased heat load. Such an ineffective gait is unlikely to have lead to selection for "bipedal" features in the postcranial skeleton.
人们普遍认为，早期原始人类阿法南方古猿的颅后骨骼显示出对双足行走的适应性，或者至少是预适应。然而，关于陆地双足行走可能的形式仍存在争议：步态是像我们人类一样直立，还是像现存黑猩猩的双足行走那样“弯臀屈膝”。在这项研究中，我们基于文献中关于身体各部分比例的数据，使用预测动态模型来评估在这两种假设下AL - 288 - 1的机械效率。AL - 288 - 1的比例与黑猩猩双足行走的运动学不兼容，但与直立或“弯臀屈膝”的人类步态的运动学兼容。在后一种情况下，踝关节和膝关节都不会为身体推进贡献大量的机械功，并且预计这些关节会有净能量吸收，这将导致热负荷增加。这样一种低效的步态不太可能导致对颅后骨骼中“双足”特征的选择。
