Background

Gait initiation in level walking is suggested to take three steps before reaching steady-state walking speed. In sloped gait, it is not clear if the general recommendation of level gait can be used.

Research question

The aim of this study was to investigate (1) if steady-state walking speed is reached within four steps in sloped gait, and (2) to what extent the number of initial steps cause differences in step length, cadence and ground reaction force (GRF).

Methods

Fourteen healthy participants walked on an instrumented ramp at inclinations of 0°, ±6°, ±12°, and ±18°, covering slight (clinical application) to steep (hiking and mountaineering) slopes. The starting position on the ramp was adjusted to collect each of the first to fourth step using a 12 infrared-camera motion capture system and two force plates. For each slope condition steady-state walking speed was determined using the ratio of the braking and propulsion impulse (ratio p_ap; $\frac{p_{braking}}{p_{propulsion}}$) and the resultant Centre of Mass (CoM) speed (vel_CoM). Statistical differences between steps were calculated by using a Friedman ANOVA and pairwise post-hoc Wilcoxon tests.

Results

In all inclinations, ≥90 % (uphill) and ≥95 % (downhill) of steady-state speed regarding ratio p_ap and maximum vel_CoM was reached with the 3rd step. In the level and uphill condition the 4th step showed a slight decrease in vel_CoM. In uphill and downhill condition, the acceleration was mainly generated due to the increase in cadence with significant increases between the 1st and 2nd step as well as between the 2nd and 3rd step. A significant increase in step length was only observed in the uphill conditions.

Significance

Steady-state walking speed was reached with the 3rd step and thus, walkways which allow for two initial steps seem to be appropriate for uphill and downhill gait analysis for inclinations up to ±18°.

中文翻译：

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倾斜步态的分析：步态启动后，需要多少步才能达到稳态步行速度？

背景

建议在达到稳态步行速度之前，在水平步行中启动步态要走三步。在倾斜步态中，尚不清楚是否可以使用水平步态的一般建议。

研究问题

这项研究的目的是调查（1）倾斜步态是否能在四步内达到稳态步行速度，以及（2）初始步数在多大程度上导致步长，踏频和地面反作用力的差异（ GRF）。

方法

十四名健康的参与者在倾斜度分别为0°，±6°，±12°和±18°的仪器坡道上行走，从轻微（临床应用）到陡峭（远足和登山）的斜坡。使用12台红外摄像机运动捕捉系统和两个测力板，调整坡道上的起始位置以收集第一到第四步的每一步。对于每个斜坡条件，使用制动和推进脉冲的比值确定稳态行走速度（比率_ap； $\frac{p_{b\mathrm{[R}\mathrm{一种}ķ\mathrm{一世}ñG}}{p_{p\mathrm{[R}Øpü升s\mathrm{一世}Øñ}}$）以及由此产生的质心（CoM）速度（vel _CoM）。使用Friedman ANOVA和成对事后Wilcoxon检验计算步骤之间的统计差异。

结果

在第三个步骤中，关于比率_ap和最大vel _CoM，在所有倾斜下，稳态速度的≥90％（上坡）和≥95％（下坡）。在水平和上坡条件下，第四步显示vel _CoM略有下降。在上坡和下坡条件下，加速度主要是由于踏频的增加而产生的，在第一步和第二步之间以及第二步和第三步之间踏步明显增加。仅在上坡条件下才观察到步长的显​​着增加。

意义

第三步达到了稳态行走速度，因此，允许两个初始步骤的人行道似乎适用于上坡和下坡步态分析，最大倾斜度为±18°。