Hak Laura, van Dieën Jaap H, van der Wurff Peter, Houdijk Han
L. Hak, PhD, Research Institute MOVE, Faculty of Human Movement Sciences, VU University, Amsterdam, the Netherlands.
J.H. van Dieën, PhD, Research Institute MOVE, Faculty of Human Movement Sciences, VU University.
Phys Ther. 2014 Oct;94(10):1480-8. doi: 10.2522/ptj.20130431. Epub 2014 Jun 5.
The asymmetry in step length in prosthetic gait is often seen as a detrimental effect of the impairment; however, this asymmetry also might be a functional compensation. An advantage of a smaller step length of the nonprosthetic leg, and specifically foot forward placement (FFP), might be that it will bring the center of mass closer to the base of support of the leading foot and thus increase the backward margin of stability (BW MoS).
The purpose of this study was to characterize differences in step length, FFP, and the concomitant difference in BW MoS between steps of the prosthetic and nonprosthetic legs (referred to as prosthetic and nonprosthetic steps, respectively) of people after transtibial amputation.
This was an observational and cross-sectional study.
Ten people after transtibial amputation walked for 4 minutes on a self-paced treadmill. Step length and FFP were calculated at initial contact. The size of the BW MoS was calculated for the moment of initial contact and at the end of the double-support phase of gait.
Step length (5.4%) and FFP (7.9%) were shorter for the nonprosthetic step than for the prosthetic step. The BW MoS at initial contact was larger for the nonprosthetic step, but because of a significant leg × gait event interaction effect, BW MoS did not differ significantly at the end of the double-support phase.
All participants were relatively good walkers (score of E on the Special Interest Group in Amputee Medicine [SIGAM] scale).
The smaller step length and FFP of the nonprosthetic step help to create a larger BW MoS at initial contact for the nonprosthetic step compared with the prosthetic step. Hence, step length asymmetry in people after transtibial amputation might be seen as a functional compensation to preserve BW MoS during the double-support phase to cope with the limited push-off power of the prosthetic ankle.
在假肢步态中，步长不对称常常被视为损伤的有害影响；然而，这种不对称也可能是一种功能补偿。非假肢侧腿步长较小，尤其是足部向前放置（FFP）的一个优势可能是，它会使重心更接近领先足部的支撑基底，从而增加向后的稳定裕度（BW MoS）。
本研究的目的是描述经胫截肢者假肢侧和非假肢侧腿的步长、FFP差异，以及与之相伴的BW MoS差异（分别称为假肢步和非假肢步）。
这是一项观察性横断面研究。
10名经胫截肢者在自定速度的跑步机上行走4分钟。在初始接触时计算步长和FFP。在初始接触时刻和步态双支撑期结束时计算BW MoS的大小。
非假肢步的步长（5.4%）和FFP（7.9%）比假肢步短。非假肢步在初始接触时的BW MoS更大，但由于显著的腿×步态事件交互效应，在双支撑期结束时BW MoS没有显著差异。
所有参与者步行能力相对较好（在截肢医学特别兴趣小组[SIGAM]量表上得分为E）。
与假肢步相比，非假肢步较小的步长和FFP有助于在初始接触时为非假肢步创造更大的BW MoS。因此，经胫截肢者的步长不对称可能被视为一种功能补偿，以在双支撑期保持BW MoS，应对假肢踝关节有限的蹬地力量。
