An explorative investigation of functional differences in plantar center of pressure of four foot types using sample entropy method.
An explorative investigation of functional differences in plantar center of pressure of four foot types using sample entropy method.
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DOI：
10.1007/s11517-016-1532-7
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发表时间：
2017-04
影响因子：
3.2
通讯作者：
Wang L
中科院分区：
文献类型：
--
作者：
Mei Z;Ivanov K;Zhao G;Li H;Wang L
在不同类型足部的生物力学研究中，经常使用由足底压力得出的时间或空间参数。然而，目前还没有关于足外翻、足外翻、拇外翻和正常足站立时压力中心复杂性和规律性的比较研究。我们的目的是分析这四种足部类型之间的COP样本熵特征是否有所不同。在我们的实验中，40名正常足部受试者，40名足内翻患者，19名外翻患者和36名拇外翻患者。使用FootScan®系统收集COP数据。我们使用样本熵来量化被调查的四种足型的几个参数。这是站立阶段COP的内侧-外侧(M/L)和前后(A/P)方向的位移，以及COP的垂直地面反力。为了充分检验样本熵方法量化COP组分的潜力，我们给出了两种情况的结果：计算归一化COP组分的样本熵，以及利用COP组分的原始数据计算样本熵。我们还探讨了在计算站姿阶段COP数据的样本熵时，参数m(匹配长度)和r(容差范围)的最佳值是什么。统计结果表明，一些因素对COP组分的样本熵有显著影响。左足和右足的非标准化A/P值的样本熵在正常足与外翻之间、正常足与拇外翻之间存在差异。正常足和下腔静脉患者右脚归一化M/L位移的样本熵不同。A/P和M/L位移的测量变量可用于足部功能的研究。
In the study of biomechanics of different foot types, temporal or spatial parameters derived from plantar pressure are often used. However, there is no comparative study of complexity and regularity of the center of pressure (CoP) during the stance phase among pes valgus, pes cavus, hallux valgus and normal foot. We aim to analyze whether CoP sample entropy characteristics differ among these four foot types. In our experiment participated 40 subjects with normal feet, 40 with pes cavus, 19 with pes valgus and 36 with hallux valgus. A Footscan® system was used to collect CoP data. We used sample entropy to quantify several parameters of the investigated four foot types. These are the displacement in medial–lateral (M/L) and anterior–posterior (A/P) directions, as well as the vertical ground reaction force of CoP during the stance phase. To fully examine the potential of the sample entropy method for quantification of CoP components, we provide results for two cases: calculating the sample entropy of normalized CoP components, as well as calculating it using the raw data of CoP components. We also explored what are the optimal values of parameters m (the matching length) and r (the tolerance range) when calculating the sample entropy of CoP data obtained during the stance phases. According to statistical results, some factors significantly influenced the sample entropy of CoP components. The sample entropies of non-normalized A/P values for the left foot, as well as for the right foot, were different between the normal foot and pes valgus, and between the normal foot and hallux valgus. The sample entropy of normalized M/L displacement of the right foot was different between the normal foot and pes cavus. The measured variable for A/P and M/L displacements could serve for the study of foot function.