Abstract：
Climbing animals theoretically should optimize the energetic costs of vertical climbing while also maintaining stability. Many modifications to climbing behaviors have been proposed as methods of satisfying these criteria, focusing on controlling the center of mass (COM) during ascent. However, the link between COM movements and metabolic energy costs has yet to be evaluated empirically. In this study, we manipulated climbing conditions across three experimental setups to elicit changes in COM position, and measured the impact of these changes upon metabolic costs across a sample of 14 humans. Metabolic energy was assessed via open flow respirometry, while COM movements were tracked both automatically and manually. Our findings demonstrate that, despite inducing variation in COM position, the energetic costs of climbing remained consistent across all three setups. Differences in energetic costs were similarly not affected by body mass; however, velocity had a significant impact upon both cost of transport and cost of locomotion, but such a relationship disappeared when accounting for metabolic costs per stride. These findings suggest that climbing has inescapable metabolic demands driven by gaining height, and that attempts to mitigate such a cost, with perhaps the exception of increasing speed, have only minimal impacts. We also demonstrate that metabolic and mechanical energy costs are largely uncorrelated. Collectively, we argue that these data refute the idea that efficient locomotion is the primary aim during climbing. Instead, adaptations towards effective climbing should focus on stability and reducing the risk of falling, as opposed to enhancing the metabolic efficiency of locomotion.
摘要：
从理论上讲，攀爬动物应优化垂直攀爬的能量成本，同时保持稳定性。已经提出了对攀爬行为的许多修改作为满足这些标准的方法。重点控制上升过程中的质心(COM)。然而,COM运动与代谢能量成本之间的联系尚未进行实证评估。在这项研究中,我们在三个实验设置中操纵爬升条件，以引起COM位置的变化，并测量了14个人样本中这些变化对代谢成本的影响。代谢能量通过开放流呼吸测量法进行评估，而COM运动是自动和手动跟踪的。我们的研究结果表明,尽管会引起COM位置的变化，在所有三个设置中，攀登的能量成本保持一致。能量成本的差异同样不受体重的影响；然而，速度对运输成本和运动成本都有重大影响，但是当考虑到每步的代谢成本时，这种关系就消失了。这些发现表明，攀爬具有由身高增加驱动的不可避免的代谢需求，试图减轻这种成本，也许除了提高速度，只有最小的影响。我们还证明，代谢和机械能成本在很大程度上是不相关的。总的来说，我们认为，这些数据反驳了有效运动是攀爬过程中的主要目标的观点。相反，对有效攀爬的适应应侧重于稳定性和降低跌倒风险，与提高运动的代谢效率相反。
