Pandy M G, Berme N
Mechanical Engineering Department, Stanford University, CA 94305.
J Biomech. 1989;22(6-7):725-33. doi: 10.1016/0021-9290(89)90023-7.
A three-dimensional model for normal gait formulated in Part 1 is now altered to simulate the dynamics of pathological walking. Mechanisms fundamental to the production of a normal gait pattern are systematically removed, in order to assess contributions from individual gait determinants. Four separate pathological cases are studied: a model neglecting ankle plantarflexor activity; absence of stance knee flexion-extension and foot and knee interaction; both pelvic list and transverse pelvic rotation removed; and finally, a model with all major gait determinants missing. These are used collectively to show that stance knee flexion-extension and foot and knee interaction successively dominate lower-extremity dynamical response during the single support phase of normal gait. The hip abductor muscles, while effecting pelvic list, serve to stabilize this limb, rather than actively determine whole-body vertical acceleration. Mechanisms compensating for a loss in joint motion are also explored. Complete ankle loss may be successfully compensated with increased hip abductor muscle activity; the loss of both ankle and knee, however, demand unacceptable levels of vertical pelvic displacement.
在第一部分中建立的正常步态三维模型现经修改，以模拟病态行走的动力学。为了评估各个步态决定因素的作用，系统地去除了产生正常步态模式的基本机制。研究了四个不同的病理案例：一个忽略踝跖屈肌活动的模型；缺乏站立期膝关节屈伸以及足部与膝关节相互作用的模型；同时去除骨盆倾斜和骨盆横向旋转的模型；最后，一个缺少所有主要步态决定因素的模型。这些案例共同表明，在正常步态的单支撑期，站立期膝关节屈伸以及足部与膝关节相互作用相继主导下肢的动力学响应。髋外展肌在影响骨盆倾斜的同时，起到稳定该肢体的作用，而不是主动决定全身垂直加速度。还探讨了补偿关节运动损失的机制。完全丧失踝关节功能时，可通过增加髋外展肌活动成功进行补偿；然而，踝关节和膝关节功能均丧失时，则需要不可接受的骨盆垂直位移水平。
