McElroy Eric J, Wilson Robbie, Biknevicius Audrone R, Reilly Stephen M
Department of Biology, College of Charleston, Charleston, SC 29412, USA.
J Exp Biol. 2014 Mar 1;217(Pt 5):735-42. doi: 10.1242/jeb.095620. Epub 2013 Nov 6.
The role of different limbs in supporting and propelling the body has been studied in many species with animals appearing to have either similarity in limb function or differential limb function. Differential hindlimb versus forelimb function has been proposed as a general feature of running with a sprawling posture and as benefiting sprawled postured animals by enhancing maneuvering and minimizing joint moments. Yet only a few species have been studied and thus the generality of differential limb function in running animals with sprawled postures is unknown. We measured the limb lengths of seven species of lizard and their single-limb three-dimensional ground reaction forces during high-speed running. We found that all species relied on the hindlimb for producing accelerative forces. Braking forces were forelimb dominated in four species and equally distributed between limbs in the other three. Vertical forces were dominated by the hindlimb in three species and equally distributed between the forelimb and hindlimb in the other four. Medial forces were dominated by the hindlimb in four species and equally distributed in the other three, with all Iguanians exhibiting hindlimb-biased medial forces. Relative hindlimb to forelimb length of each species was related to variation in hindlimb versus forelimb medial forces; species with relatively longer hindlimbs compared with forelimbs exhibited medial forces that were more biased towards the hindlimbs. These results suggest that the function of individual limbs in lizards varies across species with only a single general pattern (hindlimb-dominated accelerative force) being present.
不同肢体在支撑和推动身体方面所起的作用，已在许多物种中得到研究，这些动物的肢体功能似乎要么相似，要么存在差异。后肢与前肢功能的差异，已被认为是 sprawling 姿势奔跑的一个普遍特征，并且通过增强机动性和最小化关节力矩，使采取 sprawling 姿势的动物受益。然而，仅对少数物种进行了研究，因此，具有 sprawling 姿势的奔跑动物中肢体功能差异的普遍性尚不清楚。我们测量了七种蜥蜴的肢体长度，以及它们在高速奔跑时单肢的三维地面反作用力。我们发现，所有物种都依靠后肢产生加速力。在四个物种中，制动力以前肢为主，而在其他三个物种中，制动力在四肢之间平均分布。在三个物种中，垂直力以后肢为主，而在其他四个物种中，垂直力在前肢和后肢之间平均分布。在四个物种中，内侧力以后肢为主，在其他三个物种中平均分布，所有鬣蜥科动物的内侧力都偏向于后肢。每个物种的后肢与前肢长度之比，与后肢和前肢内侧力的变化有关；与前肢相比后肢相对较长的物种，其内侧力更偏向于后肢。这些结果表明，蜥蜴个体肢体的功能因物种而异，仅存在一种普遍模式（后肢主导加速力）。
