Rubenson Jonas, Lloyd David G, Besier Thor F, Heliams Denham B, Fournier Paul A
School of Human Movement and Exercise Science, The University of Western Australia, Crawley, WA, 6009, Australia.
J Exp Biol. 2007 Jul;210(Pt 14):2548-62. doi: 10.1242/jeb.02792.
Although locomotor kinematics in walking and running birds have been examined in studies exploring many biological aspects of bipedalism, these studies have been largely limited to two-dimensional analyses. Incorporating a five-segment, 17 degree-of-freedom (d.f.) kinematic model of the ostrich hind limb developed from anatomical specimens, we quantified the three-dimensional (3-D) joint axis alignment and joint kinematics during running (at approximately 3.3 m s(-1)) in the largest avian biped, the ostrich. Our analysis revealed that the majority of the segment motion during running in the ostrich occurs in flexion/extension. Importantly, however, the alignment of the average flexion/extension helical axes of the knee and ankle are rotated externally to the direction of travel (37 degrees and 21 degrees , respectively) so that pure flexion and extension at the knee will act to adduct and adbuct the tibiotarsus relative to the plane of movement, and pure flexion and extension at the ankle will act to abduct and adduct the tarsometatarsus relative to the plane of movement. This feature of the limb anatomy appears to provide the major lateral (non-sagittal) displacement of the lower limb necessary for steering the swinging limb clear of the stance limb and replaces what would otherwise require greater adduction/abduction and/or internal/external rotation, allowing for less complex joints, musculoskeletal geometry and neuromuscular control. Significant rotation about the joints' non-flexion/extension axes nevertheless occurs over the running stride. In particular, hip abduction and knee internal/external and varus/valgus motion may further facilitate limb clearance during the swing phase, and substantial non-flexion/extension movement at the knee is also observed during stance. Measurement of 3-D segment and joint motion in birds will be aided by the use of functionally determined axes of rotation rather than assumed axes, proving important when interpreting the biomechanics and motor control of avian bipedalism.
尽管在探索双足行走诸多生物学方面的研究中已经对行走和奔跑鸟类的运动学进行了检验，但这些研究在很大程度上限于二维分析。我们利用从解剖标本构建的鸵鸟后肢五节段、17自由度运动学模型，对最大的鸟类双足动物鸵鸟在奔跑（约3.3米/秒）时的三维关节轴排列和关节运动学进行了量化。我们的分析表明，鸵鸟奔跑时大部分节段运动发生在屈伸过程中。然而，重要的是，膝关节和踝关节平均屈伸螺旋轴的排列相对于行进方向向外旋转（分别为37度和21度），这样膝关节处的单纯屈伸将使胫跗骨相对于运动平面内收和外展，而踝关节处的单纯屈伸将使跗跖骨相对于运动平面外展和内收。肢体解剖学的这一特征似乎为摆动肢体避开支撑肢体所需的下肢主要侧向（非矢状面）位移提供了条件，取代了否则将需要的更大内收/外展和/或内旋/外旋，从而使关节、肌肉骨骼几何结构和神经肌肉控制更简单。不过，在整个奔跑步幅中，关节的非屈伸轴仍会发生显著旋转。特别是，髋关节外展以及膝关节的内/外和内翻/外翻运动可能在摆动期进一步促进肢体间隙，并且在支撑期也观察到膝关节有大量非屈伸运动。使用功能确定的旋转轴而非假定轴将有助于测量鸟类的三维节段和关节运动，这在解释鸟类双足行走的生物力学和运动控制时被证明是很重要的。
