McFadyen B J, Carnahan H
Département de Physiothérapie, Faculté de Médicine, Université Laval,Québec, Canada.
Exp Brain Res. 1997 May;114(3):500-6. doi: 10.1007/pl00005659.
The control of locomotion has been studied from various perspectives related to the tasks of pattern generation, equilibrium control or adaptation to the environment. The last of these locomotor components has received comparably less attention, specifically pertaining to anticipatory adjustments. Continuing the work which has been conducted on both humans and cats, the present paper explores the nature of the differences in anticipatory locomotor adjustments for obstacle avoidance versus the accommodation to level changes. Six subjects walked in six different environments including no obstructions, a simple obstacle, two different level changes (a platform and stairs), and a combination of an obstacle with each respective level change. Full dynamic analyses allowed comparison of muscle torques as well as muscle power generated and absorbed at the lower limb joints across conditions. It was found that the previously shown robust lower limb reorganization characterized by a knee flexor generation strategy was upheld in all conditions when the obstacle was present. Pure level changes involved an augmentation of the ongoing hip strategy inherent in normal level walking. In the compound environment of obstructed level changes, subjects chose to combine an augmentation of hip flexor power with a reorganization to active knee flexion. The results are discussed from the point of view of general principles of mechanical coordination and the exploitation of intersegmental dynamics for foot transport.
人们从与运动模式生成、平衡控制或环境适应任务相关的各种角度对运动控制进行了研究。这些运动组成部分中的最后一个受到的关注相对较少，特别是与预期调整有关的方面。在对人类和猫进行研究的基础上，本文探讨了在避障与适应高度变化时预期运动调整的差异本质。六名受试者在六种不同环境中行走，包括无障碍物、一个简单障碍物、两种不同的高度变化（一个平台和楼梯），以及障碍物与每种高度变化的组合。完整的动态分析允许比较不同条件下下肢关节产生和吸收的肌肉扭矩以及肌肉功率。结果发现，当存在障碍物时，先前显示的以屈膝肌产生策略为特征的强大下肢重组在所有条件下都得以维持。单纯的高度变化涉及正常平地行走中固有的持续髋部策略的增强。在有障碍物的高度变化的复合环境中，受试者选择将髋屈肌力量的增强与向主动屈膝的重组相结合。从机械协调的一般原则以及利用节段间动力学进行足部运动的角度对结果进行了讨论。
