THE ROLE OF INTERSEGMENTAL DYNAMICS DURING RAPID LIMB OSCILLATIONS
THE ROLE OF INTERSEGMENTAL DYNAMICS DURING RAPID LIMB OSCILLATIONS
复制标题
DOI：
10.1016/0021-9290(86)90137-5
复制
发表时间：
1986-01-01
影响因子：
2.4
通讯作者：
ZERNICKE, RF
中科院分区：
文献类型：
--
作者：
HOY, MG;ZERNICKE, RF
研究了肌肉、惯性和重力力矩对快速、多节段肢体振动的交互动力学效应。利用三段刚体运动方程，计算了成年脊椎猫抖足反应的稳态周期中髋关节、膝关节和踝关节的节间动力学。拍摄后肢运动轨迹以获得节段性运动学，并与电影同步记录三个关节的屈伸肌势。在摇爪反应中出现的节段性振荡是主动和被动肌腱力、惯性力和重力相互作用的结果。在稳态振荡期间，从近端关节(髋关节)到最远端关节(脚踝)，关节偏移的幅度、最大角速度和最大角加速度量值单调且显著增加。与这些运动学关系相反，髋部和膝部的净力矩的最大值在大小上是相同的，但显著低于踝关节的大净力矩。在踝关节和膝关节，屈肌和伸肌的力矩是相等的，但在臀部，屈肌的峰值力矩显著大于伸肌的力矩。髋部的肌力矩不仅起到抵消更远端节段的加速度的作用，还起到保持后肢姿势方向的作用。膝盖处的大肌力矩起着抵消爪子大角加速所产生的大惯性力矩的作用。在脚踝，肌肉瞬间控制着爪子加速的产生。在踝关节和膝关节，肌力矩通过显示和反转关节运动来控制肢体动力学，而对踝关节和膝关节力矩起作用的主动肌力则来自于主动肌腱单位的延长。与更远端的关节相比，横跨臀部的活跃肌肉主要是由于惯性力和重力矩之间的相互作用而缩短的。肌肉功能和运动数据解释了中央控制机制和多节段、摆动的肢体节段在爪子抖动反应期间发生的复杂相互作用的关键特征。
The interactive dynamic effects of muscular, inertial and gravitational moments on rapid, multisegmented limb oscillations were studied. Using three-segment, rigid-body equation of motion, hip, knee and ankle intersegmental dynamics were calculated for the steady-state cycles of the paw-shake response in adult spinal cats. Hindlimb trajectories were filmed to obtain segmental kinematics, and myopotentials of flexors and extensors at each of the three joints were recorded synchronously with the cine film. The segmental oscillations that emerged during the paw-shake response were a consequence of an interplay between active and passive musculotendinous forces, inertial forces, and gravity. During steady-state oscillations, the amplitudes of joint excursions, peak angular velocities, and peak angular acclerations increased monotonically and significantly in magnitude from the proximal joint (hip) to the most distal joint (ankle). In contrast to these kinematic relationships, the maximal values of net moments at the hip and knee were equal in magnitude, but of significantly lower magnitude than the large net moment at the ankle joint. At both the ankle and the knee, the flexor and extensor muscle moments were equal, but at the hip the magnitude of the peak flexor muscle moment was significantly greater than the extensor muscle moment. Muscle moments at the hip not only acted to counterbalnce accelerations of the more distal segments, but also acted to maintain the postural orientation of the hindlimb. Large muscle moments at the knee functioned to counterbalance the large inertial moments generated by the large angular accelerations of the paw. At the ankle, the muscle moments dominated the generation of the paw accelerations. At the ankle and the knee, muscle moments controlled limb dynamics by showing and reversing joint motions, and the active muscle forces contributing to ankle and knee moments were derived from lengthening of active musculotendinous units. In contrast to the more distal joints, the active muscles crossing the hip predominantly shortened as a result of the interplay among inertial forces and gravitational moments. The muscle function and kinetic data explain key features of the complex interactions that occur between central control mechanisms and multi-segmented, oscillating limb segments during the paw-shake response.