Balmaseda M T, Koozekanani S H, Fatehi M T, Gordon C, Dreyfuss P H, Tanbonliong E C
Department of Physical Medicine, Ohio State University, Columbus.
Arch Phys Med Rehabil. 1988 Dec;69(12):1009-12.
We analyzed the effects of an ankle-foot orthosis (AFO) on the ground reaction forces, the position of the center of pressure, and the timing of stance phase events during walking in 18 healthy volunteers between the ages of 19 and 38 years. The magnitude and direction of the ground reaction forces and the locus of the center of pressure were recorded every one-sixtieth of a second during free-speed ambulation. The horizontal force components of the ground reaction force were plotted vectorially, and the vertical force component was displayed by its magnitude expressed in percentage body weight. All this information was superimposed on the subject's footprint and statistically analyzed, comparing right to left, narrow to wide, and ipsilateral to contralateral use of an AFO. The results showed a significant reduction in the mean duration of the stance phase of 4.83% (p less than 0.05) with the AFO. This reduction was due primarily to the significant reduction during midstance of 7% (p less than 0.025), which was more pronounced with the use of the wide AFO. Using an AFO also resulted in a mean increase of 20% (p less than 0.05) in the vertical force magnitude at the end of push-off. With the use of an AFO, there was a shift of the point of impact at heel strike to a more posterior location and a shift of the trajectory of the center of pressure to a more lateral position throughout the stance phase. These changes should be kept in mind when prescribing an ankle-foot orthosis.
我们分析了踝足矫形器（AFO）对18名年龄在19至38岁之间的健康志愿者行走时地面反作用力、压力中心位置以及站立相事件时间的影响。在自由速度行走过程中，每六十分之一秒记录一次地面反作用力的大小和方向以及压力中心的轨迹。地面反作用力的水平力分量以矢量形式绘制，垂直力分量以体重百分比表示的大小显示。所有这些信息都叠加在受试者的足迹上并进行统计分析，比较使用AFO时左右、窄与宽以及同侧与对侧的情况。结果显示，使用AFO时站立相的平均持续时间显著缩短了4.83%（p<0.05）。这种缩短主要是由于支撑中期显著缩短了7%（p<0.025），使用宽AFO时更为明显。使用AFO还导致蹬离末期垂直力大小平均增加了20%（p<0.05）。使用AFO时，足跟触地时的撞击点向后移位，并且在整个站立相期间压力中心轨迹向更外侧移位。在开具踝足矫形器处方时应牢记这些变化。
