Hill S W, Patla A E, Ishac M G, Adkin A L, Supan T J, Barth D G
Department of Kinesiology, University of Waterloo, Ontario, Canada.
J Biomech. 1999 May;32(5):545-9. doi: 10.1016/s0021-9290(98)00168-7.
Our goal was to document the kinetic strategies for obstacle avoidance in below-knee amputees. Kinematic data were collected as unilateral below-knee traumatic amputees stepped over obstacles of various heights in the walking path. Inverse dynamics were employed to calculate power profiles and work during the limb-elevation and limb-lowering phases. Limb elevation was achieved by employing a different strategy of intra-limb interaction for elevation of the prosthetic limb than for the sound limb, which was similar to that seen in healthy adult non-amputees. As obstacle height increased, prosthetic side knee flexion was increased by modulating the work done at the hip, and not the knee, as seen on the sound side. Although the strength of the muscles about the residual knee was preserved, the range of motion of that knee had previously been found to be somewhat limited. Perhaps more importantly, potential instability of the interface between the stump and the prosthetic socket, and associated discomfort at the stump could explain the altered limb-elevation strategy. Interestingly, the limb-lowering strategy seen in the sound limb and in non-amputees already features modulation of rotational and translational work at the hip, so an alternate strategy was not required. Thus, following a major insult to the sensory and neuromuscular system, the CNS is able to update the internal model of the locomotor apparatus as the individual uses the new limb in a variety of movements, and modify control strategies as appropriate.
我们的目标是记录膝下截肢者避免障碍物的动力学策略。当单侧膝下创伤性截肢者跨过步行路径中不同高度的障碍物时，收集运动学数据。采用逆动力学方法计算肢体抬高和降低阶段的功率分布和功。与健全的成年非截肢者类似，假肢肢体抬高采用了与健全肢体不同的肢体内部相互作用策略。随着障碍物高度增加，假肢侧膝关节屈曲通过调节髋部而非健全侧所见的膝部所做的功而增加。尽管残膝周围肌肉的力量得以保留，但此前发现该膝关节的活动范围有所受限。或许更重要的是，残端与假肢接受腔之间界面的潜在不稳定性以及残端相关的不适感可以解释肢体抬高策略的改变。有趣的是，健全肢体和非截肢者中所见的肢体降低策略已经具有髋部旋转和平移功的调节，因此不需要替代策略。因此，在感觉和神经肌肉系统受到重大损伤后，中枢神经系统能够在个体在各种运动中使用新肢体时更新运动装置的内部模型，并适当地修改控制策略。
