Sylvester Adam D, Kramer Patricia A
Department of Mechanical, Aerospace and Biomedical Engineering, The University of Tennessee, Knoxville, TN 37996, USA.
Am J Phys Anthropol. 2008 Apr;135(4):484-8. doi: 10.1002/ajpa.20752.
Many reasons for the emergence of bipedalism have been proposed, including postural arguments which highlight that a sub-optimal form of bipedalism ("shuffling") might have been used by protohominids to cover short distances between resources that require bipedal standing. Bipedal shuffling may have been employed because it avoids the cost of raising the trunk from the quadrupedal orientation, which we assume is the habitual locomotor stance of protohominids. To date, these postural proposals have not been analytically assessed, a lack we rectify herein. Our model seeks to specify a threshold distance, below which bipedal shuffling uses less energy than quadrupedalism. Parameters for the model include the mechanical cost of transport, the ratio of bipedal to quadrupedal cost, and the cost associated with raising the trunk. We found that, using reasonable model parameters, open distances of approximately 9-16 m support the use of bipedal shuffling. Protohominids may have used shuffling as an energetically effective way to traverse between resource patches.
关于两足行走出现的原因，人们提出了很多观点，其中包括姿势方面的观点，这些观点强调原始人类可能曾采用一种不太理想的两足行走形式（“拖着脚走”）来在需要两足站立的资源之间短距离移动。两足拖着脚走可能是因为它避免了将躯干从四足姿势抬起的成本，我们假设四足姿势是原始人类习惯性的运动姿态。迄今为止，这些姿势方面的观点尚未得到分析评估，我们在此弥补这一不足。我们的模型旨在确定一个阈值距离，在该距离以下，两足拖着脚走比四足行走消耗的能量更少。该模型的参数包括运输的机械成本、两足与四足成本的比率以及与抬起躯干相关的成本。我们发现，使用合理的模型参数，大约9 - 16米的开阔距离支持两足拖着脚走的方式。原始人类可能曾将拖着脚走作为在资源斑块之间移动的一种能量高效的方式。
