Influence of contextual task constraints on preferred stride parameters and their variabilities during human walking.
Influence of contextual task constraints on preferred stride parameters and their variabilities during human walking.
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DOI：
10.1016/j.medengphy.2015.06.010
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发表时间：
2015-10
影响因子：
2.2
通讯作者：
Adamczyk PG
中科院分区：
文献类型：
--
作者：
Ojeda LV;Rebula JR;Kuo AD;Adamczyk PG
走路并不总是一项自由和不受阻碍的任务。日常活动，如成对、成组或在结构化的人行道上行走，会限制可接受的步态模式，导致运动行为与更多自我选择的步态不同。这种不同的环境可能导致与典型实验室实验中观察到的步态不同的步态表现，例如，在跑步机行走时。我们试图通过比较不同条件下在地面上和在跑步机上行走时的步态参数及其变异性，来系统地衡量这些任务限制的影响。我们从安装在脚上的惯性传感器重建了脚的运动，并表征了受试者在直线走廊和跑步机上走在地面上时的向前、横向和角度脚的放置。在地面上行走有三种不同的形式：没有约束(自选，SS)；故意改变行走速度(Self-Varied，SV)；以及跟随编程为变速的玩具步速汽车(Extran-Varied，EV)。我们预计，这些条件将在统计上显示出步长和速度之间以及步长和步幅周期之间的相似关系。我们还预计，跑步机步行(TM)将在两个方面有所不同：第一，步长和步长的变化符合与正常关系相反的斜率的恒速限制；第二，步长会减少，导致在地面条件下没有观察到的步长和速度的组合。结果表明，所有地面条件都使用相似的步长-速度关系，跑步机步行的变异性符合恒速约束线，正如预期的那样。在TM和EV条件下都观察到步长缩短，这表明由于意识的提高或为意外的变化或问题做准备而产生的适应。我们还评估了受限和非受限任务中的步幅变异性。我们观察到，在跑步机行走中，侧向变异性减少而向前变异性增加，通常观察到的足部较宽位置和外部脚部旋转之间的相关性被消除。步态参数及其变异性明显受行走任务的环境和限制条件的影响。
Walking is not always a free and unencumbered task. Everyday activities such as walking in pairs, in groups, or on structured walkways can limit the acceptable gait patterns, leading to motor behavior that differs from that observed in more self-selected gait. Such different contexts may lead to gait performance different than observed in typical laboratory experiments, for example, during treadmill walking. We sought to systematically measure the impact of such task constraints by comparing gait parameters and their variability during walking in different conditions over-ground, and on a treadmill. We reconstructed foot motion from foot-mounted inertial sensors, and characterized forward, lateral and angular foot placement while subjects walked over-ground in a straight hallway and on a treadmill. Over-ground walking was performed in three variations: with no constraints (self-selected, SS); while deliberately varying walking speed (self-varied, SV); and while following a toy pace car programmed to vary speed (externally-varied, EV). We expected that these conditions would exhibit a statistically similar relationship between stride length and speed, and between stride length and stride period. We also expected treadmill walking (TM) would differ in two ways: first, that variability in stride length and stride period would conform to a constant-speed constraint opposite in slope from the normal relationship; and second, that stride length would decrease, leading to combinations of stride length and speed not observed in over-ground conditions. Results showed that all over-ground conditions used similar stride length-speed relationships, and that variability in treadmill walking conformed to a constant-speed constraint line, as expected. Decreased stride length was observed in both TM and EV conditions, suggesting adaptations due to heightened awareness or to prepare for unexpected changes or problems. We also evaluated stride variability in constrained and unconstrained tasks. We observed that in treadmill walking, lateral variability decreased while forward variability increased, and the normally-observed correlation between wider foot placement and external foot rotation was eliminated. Preferred stride parameters and their variability appear significantly influenced by the context and constraints of the walking task.