Anatomical, physiological, and kinesiological study of bipedal capability in the Japanese macaque

习惯性的两足动物只在活着的灵长类动物中观察到，而活着的人类是高度专业化的两足动物。这一事实导致了研究人类两足动物适应过程的比较材料的缺乏。为了解决这个问题，我们对两足猕猴进行了形态学、生理学和运动学方面的研究，以进行传统的货币表演。实验是与索猴表演协会(熊本)进行的，研究了在跑步机上运动时的运动能量学和运动学。我们检查了两名受试者(10岁和4岁)的运动能量学。能量消耗估计为以体重为标准的二氧化碳产生率。步行速度为1.5~4.5公里/小时。两足步行和四足步行的能量消耗与步行速度呈线性相关。两足行走的成本比四足行走的成本高约30%，在年长的受试者中，这些比率在年轻受试者中高出20%-25%，这些比率在每个人中都是相当恒定的，无论行走速度如何。我们试探性地使用(经验上已知的)正常呼吸商(0.85)将观测到的二氧化碳产生率转换为耗氧量，并获得了先前研究中揭示的类似值。使用双摄像机系统进行的运动学分析表明，与正常(实验)猴子相比，受训猴子的步幅更大，步幅频率更低。这些特征与较大的后肢关节角度相关，受训猴子的膝关节表现出类似人类的双膝动作。这会导致躯干在单肢支撑阶段向上平移，这在正常猴子的双肢支撑阶段可以观察到。这些运动学特征表明，这些训练有素的猕猴通过发展更像人类的两足步态来节省两足行走的成本，这表明了两足行走的潜力和可塑性。

Habitual bipedalism is only observed in humans among living primates whereas living humans are highly specialized bipeds. This fact causes a lack of comparative material to study adaptive process of human bipedalism. To cope with this problem, we conducted a morphological, physiological and kinesiological study on bipedally trained macaques for traditional money performance. Experiments were conducted with the Suo Monkey Performance Association (Kumamoto) and investigated tocomotor energetics and kinematics during locomotion on a treadmill. We examined locomotor energetics on two subjects (10 and 4 yrs in age). Energy expenditure was estimated as the rate of CO2 production standardized by the body mass. The walking velocity was 1.5-4.5 km/h. Energetic costs increased linearly correlated with walking velocities in bipedal and quadrupedal walk. Cost of bipedal walk was greater than that of quadrupedalism by ca, 30% in the elder subject and by 20-25% in the younger subject These ratios are rather constant in each individual regardless of walking velocity. We tentatively converted the observed CO2 production rate to oxygen consumption using a (empirically known) normal respiratory quotient (0.85) and obtained similar values revealed in previous studies. Kinematic analysis by using a two video camera system revealed that the trained monkeys took longer strides and fewer stride frequencies compared with normal (experimental) monkeys. These features are correlated with larger joint angles of the hindlimb and the knee joint of the trained monkey exhibited a human-like double knee action. This causes an upward translation of the trunk during the single limb support phase, which is observed in the double limb support phase in the normal monkeys. These kinematic features suggest that these trained macaques saved the costs of bipedalism by developing more human like bipedal gait, indicating the potential and plasticity for bipedalism.