Kinematic variability, fractal dynamics and local dynamic stability of treadmill walking.
Kinematic variability, fractal dynamics and local dynamic stability of treadmill walking.
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DOI：
10.1186/1743-0003-8-12
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发表时间：
2011-02-24
影响因子：
5.1
通讯作者：
Dériaz O
中科院分区：
文献类型：
--
作者：
Terrier P;Dériaz O
电动粉碎机广泛用于研究或临床治疗。文献中已经报道了与地面行走（OW）相比，跑步机行走（TW）引起的运动学、动力学和能量学变化较小。本研究的目的是表征OW和TW之间的差异，在步幅到步幅的变异性。经典（标准差，SD）和非线性（分形动力学，局部动态稳定性）的方法。此外，还对不同变异性指标之间的相关性进行了分析。20名健康受试者以随机顺序进行10分钟TW和OW。三轴加速计记录躯干加速度。运动变异性计算为标准化步幅中加速度模式的平均SD（MeanSD）。通过步幅间隔的去趋势波动分析（DFA）评估分形动力学（标度指数α）。通过计算加速度信号的最大李雅普诺夫指数来估计系统的短期和长期动态稳定性。与OW相比，TW没有改变运动学步态变异性（多变量T2，p = 0.87）。相反，TW显着修改分形动力学（t检验，p = 0.01），以及短期和长期的局部动态稳定性（T2 p = 0.0002）。各变异性指标间除MeanSD与TW动态稳定性呈显著负相关外（3 × 6典型相关，r = 0.94），其余指标间无相关性。跑步机诱导的步幅间隔和步态稳定性增加的相关性较低的模式，但没有修改健康受试者的运动变异性。这可能是由于跑步机行走引起的感知信息的变化，这将影响步态的运动控制，因此特别是改变连续步幅之间的非线性依赖关系。因此，在每个方案设计中，步行类型（即跑步机或地上）是重要的考虑因素。
Motorized treadmills are widely used in research or in clinical therapy. Small kinematics, kinetics and energetics changes induced by Treadmill Walking (TW) as compared to Overground Walking (OW) have been reported in literature. The purpose of the present study was to characterize the differences between OW and TW in terms of stride-to-stride variability. Classical (Standard Deviation, SD) and non-linear (fractal dynamics, local dynamic stability) methods were used. In addition, the correlations between the different variability indexes were analyzed. Twenty healthy subjects performed 10 min TW and OW in a random sequence. A triaxial accelerometer recorded trunk accelerations. Kinematic variability was computed as the average SD (MeanSD) of acceleration patterns among standardized strides. Fractal dynamics (scaling exponent α) was assessed by Detrended Fluctuation Analysis (DFA) of stride intervals. Short-term and long-term dynamic stability were estimated by computing the maximal Lyapunov exponents of acceleration signals. TW did not modify kinematic gait variability as compared to OW (multivariate T2, p = 0.87). Conversely, TW significantly modified fractal dynamics (t-test, p = 0.01), and both short and long term local dynamic stability (T2 p = 0.0002). No relationship was observed between variability indexes with the exception of significant negative correlation between MeanSD and dynamic stability in TW (3 × 6 canonical correlation, r = 0.94). Treadmill induced a less correlated pattern in the stride intervals and increased gait stability, but did not modify kinematic variability in healthy subjects. This could be due to changes in perceptual information induced by treadmill walking that would affect locomotor control of the gait and hence specifically alter non-linear dependencies among consecutive strides. Consequently, the type of walking (i.e. treadmill or overground) is important to consider in each protocol design.
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影响因子：
3.3
作者：
Hausdorff, JM;Purdon, PL;Goldberger, AL
通讯作者：
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影响因子：
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10.1682/jrrd.2007.02.0022
发表时间：
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影响因子：
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10.1016/j.physa.2007.02.061
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2007-07-01
影响因子：
3.3
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1.4
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