Hicheur Halim, Terekhov Alexander V, Berthoz Alain
Laboratoire de Physiologie de la Perception et de l'Action, Collège de France, Paris, France.
J Neurophysiol. 2006 Sep;96(3):1406-19. doi: 10.1152/jn.00289.2006. Epub 2006 Jun 21.
To study intersegmental coordination in humans performing different locomotor tasks (backward, normal, fast walking, and running), we analyzed the spatiotemporal patterns of both elevation and joint angles bilaterally in the sagittal plane. In particular, we determined the origins of the planar covariation of foot, shank, and thigh elevation angles. This planar constraint is observable in the three-dimensional space defined by these three angles and corresponds to the plane described by the three time-varying elevation angle variables over each step cycle. Previous studies showed that this relation between elevation angles constrains lower limb coordination in various experimental situations. We demonstrate here that this planar covariation mainly arises from the strong correlation between foot and shank elevation angles, with thigh angle independently contributing to the pattern of intersegmental covariation. We conclude that the planar covariation of elevation angles does not reflect central constraints, as previously suggested. An alternative approach for analyzing the patterns of coordination of both elevation and joint (hip, knee, and ankle) angles is used, based on temporal cross-correlation and phase relationships between pairs of kinematic variables. We describe the changes in the pattern of intersegmental coordination that are associated with the changes of locomotor modes and locomotor speeds. We provide some evidence for a distinct control of thigh motion and discuss the respective contributions of passive mechanical factors and of active (arising from neural control) factors to the formation and the regulation of the locomotor pattern throughout the gait cycle.
为了研究人类在执行不同运动任务（向后、正常、快走和跑步）时的节段间协调性，我们分析了矢状面内双侧的抬高和关节角度的时空模式。具体而言，我们确定了足、小腿和大腿抬高角度的平面协变的起源。这种平面约束在由这三个角度定义的三维空间中是可观察到的，并且对应于每个步周期中三个随时间变化的抬高角度变量所描述的平面。先前的研究表明，抬高角度之间的这种关系在各种实验情况下都会限制下肢的协调性。我们在此证明，这种平面协变主要源于足和小腿抬高角度之间的强相关性，而大腿角度独立地对节段间协变模式有贡献。我们得出结论，抬高角度的平面协变并不像先前所认为的那样反映中枢约束。基于运动学变量对之间的时间互相关和相位关系，我们采用了一种分析抬高和关节（髋、膝和踝）角度协调性模式的替代方法。我们描述了与运动模式和运动速度变化相关的节段间协调模式的变化。我们为大腿运动的独特控制提供了一些证据，并讨论了被动机械因素和主动（源于神经控制）因素在整个步态周期中对运动模式的形成和调节的各自贡献。
