A paradigm shift in locomotion mechanics: collision loss explains functional requirements

陆地运动在能量上是昂贵的，是哺乳动物等活跃生物体能量平衡的关键特征。经济的运动通常归因于步幅周期内能量的“恢复”。然而，这种观点留下了许多关于运动成本的来源以及这对动物功能设计意味着什么的问题。为了正确解释陆地形式的运动系统适应性修改的功能后果，有必要了解运动的机械成本的来源。这项研究计划是围绕着一种新的观点构建的，即地球运动需要与地面发生耗散碰撞，正是这种损失占了运动中的主要能量消耗。碰撞损失直到最近才被确认为人类运动中的一个因素，而在动物运动中通常被忽视。我的实验室已经成功地证明了碰撞损失在各种运动系统中的作用，如猿类的腕部运动和马的奔跑。对这种不同类型的运动的适用性强烈地表明，这一观点定义了动物运动的新范式。运动中碰撞成本观点的论证和验证将需要建模和实验评估之间的协调综合。这项研究计划有可能对哺乳动物运动研究的角度和总体运动策略的评估产生重大影响。尽管更复杂，但对地上运动的分析对生物生物学有更广泛的影响，无论是在哺乳动物的支系中，还是扩展到其他重要的群体中。适用问题的例子包括对灭绝的哺乳动物、始祖龙(恐龙)的运动的解释，或者人类祖先从四足动物到两足动物的转变。

Terrestrial locomotion is energetically expensive and is a critical feature of the energy balance of active organisms such as mammals. Economical locomotion is commonly attributed to 'recovery' of energy within the stride cycle. However, this perspective leaves unanswered a number of questions about the source of the cost of locomotion and what this means to the functional design of animal. In order to properly interpret the functional consequences of adaptive modifications of the locomotory system in terrestrial forms it is necessary to understand the source of the mechanical cost of locomotion. This program of study is constructed around the novel perspective that terrestrial locomotion requires dissipative collisions with the ground and it is this loss that accounts for the major energy expenditure in locomotion. Collision losses have only recently been identified as a factor in human locomotion, and have been generally neglected in animal locomotion. My lab has successfully demonstrated the role of collision loss in locomotion systems as varied as ape brachiation and horse galloping. Applicability to such diverse types of locomotion strongly suggests that this perspective defines a new paradigm in animal locomotion. Demonstration and verification of the collision cost perspective in locomotion will require a coordinated synthesis between modeling and experimental evaluation. The research program has the potential to provide a substantial influence on the perspective of locomotion research and the evaluation of movement strategies in mammals in general. Though more complex, the analysis of overground locomotion has more general implications for organismal biology, whether in mammalian clades or expanded to other important groups. Examples of applicable problems include the interpretation of locomotion in extinct mammals, archosaurs (dinosaurs) or the transition from quadrupedal to bipedal locomotion in human ancestors.