Fractal dynamics of human gait: Stability of long-range correlations in stride interval fluctuations
Fractal dynamics of human gait: Stability of long-range correlations in stride interval fluctuations
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DOI：
10.1152/jappl.1996.80.5.1448
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发表时间：
1996-05-01
影响因子：
3.3
通讯作者：
Goldberger, AL
中科院分区：
文献类型：
--
作者：
Hausdorff, JM;Purdon, PL;Goldberger, AL
分形动力学最近被发现在明显的“噪声”变化的步幅区间的人类行走。对这些步幅波动的动态分析揭示了一种自相似的模式：在一个时间尺度上的波动在统计上与多个其他时间尺度上的波动相似，至少超过数百步，而健康受试者以正常速度行走。为了研究这种分形特性的稳定性，我们分析了在正常、慢速和快速下步行1小时的健康受试者的数据。步幅间隔波动表现出与幂律衰减的长期相关性，在所有3种步行速率下，步幅可达1000步。相比之下，在按节奏行走时，这些长期相关性消失了；步幅间隔的变化是随机的（不相关的）和非分形的。自发行走期间观察到的长期相关性不受时间序列中漂移去除的影响。因此，自发步幅间隔的分形动力学通常是相当稳健的，并且是运动系统所固有的。此外，神经输出的这种分形特性可能与负责控制行走节奏的高级神经中枢有关。
Fractal dynamics were recently detected in the apparently ''noisy'' variations in the stride interval of human walking. Dynamical analysis of these step-to-step fluctuations revealed a self-similar pattern: fluctuations at one time scale are statistically similar to those at multiple other time scales, at least over hundreds of steps, while healthy subjects walk at their normal rate. To study the stability of this fractal property, we analyzed data obtained from healthy subjects who walked for 1 h at their usual, slow, and fast paces. The stride interval fluctuations exhibited long-range correlations with power-law decay for up to 1,000 strides at all 3 walking rates. In contrast, during metronomically paced walking, these long-range correlations disappeared; variations in the stride interval were random (uncorrelated) and nonfractal. The long-range correlations observed during spontaneous walking were not affected by removal of drifts in the time series. Thus the fractal dynamics of spontaneous stride interval are normally quite robust and intrinsic to the locomotor system. Furthermore, this fractal property of neural output may be related to the higher nervous centers responsible for the control of walking rhythm.