Background

Flatfoot has a very high incidence of obese children. Functional parameters such as plantar pressures and center of pressure (COP) are sensitive to foot type. However, previous foot biomechanical studies of obese children rarely excluded the flatfoot as a prerequisite of the participants involved.

Research question

This study aimed to determine whether it is essential to define flatfoot as a subject screening criterion in the foot biomechanical study for obese children.

Methods

Foot types were classified by arch index (AI). Totally 21 obese children with flatfoot (OF group) along with matched control groups of obese children with normal foot (ON group) and normal-weighted children with flatfoot (NF group) were selected from our database. Barefoot walking trails were conducted using Footscan® plate system. Peak force (PF), peak pressure (PP), pressure-time integral (PTI), contact area (CA) and COP data were recorded. Independent t-test and effect size were used to compare the data between the study group and the control groups. Intraclass correlation coefficient was used to measure the between-trail reliability for the dependent variables.

Results

In comparison with the OF group, an upward trend for PF, PP and PTI was found for the ON group, while an opposite tendency for the NF group. The OF group displayed a significant larger CA under the midfoot region than the NF group even if there is no significant difference for AI. The OF group displayed a more medial shift of COP progression compared to the ON group. But no significant differences were found for COP parameters between the OF group and the NF group.

Significance

This study provided substantial evidence to support that prospective foot biomechanical research on the obese group needs to identify the flatfoot as one of the subject screening criteria to carry out more reliable results without producing confounding effects.

中文翻译：

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影响肥胖儿童足底压力和压力中心的混合因素：肥胖和扁平足。

背景

扁平足肥胖儿童的发病率很高。诸如足底压力和压力中心（COP）的功能参数对脚型敏感。但是，先前对肥胖儿童的足部生物力学研究很少将扁平足排除为参与者的先决条件。

研究问题

这项研究旨在确定是否有必要将扁平足定义为肥胖儿童足部生物力学研究的主题筛选标准。

方法

足部类型通过足弓指数（AI）进行分类。从我们的数据库中，总共选择了21名肥胖的扁平足儿童（OF组）以及相匹配的正常脚肥胖儿童对照组（ON组）和正常体重的扁平足儿童（NF组）。使用Footscan®板系统进行了赤脚步行。记录峰值力（PF），峰值压力（PP），压力-时间积分（PTI），接触面积（CA）和COP数据。使用独立的t检验和效应量比较研究组和对照组之间的数据。类内相关系数用于度量因变量的踪迹间可靠性。

结果

与OF组相比，ON组的PF，PP和PTI呈上升趋势，而NF组则呈相反的趋势。即使AI并无显着差异，OF组的足中部CA也比NF组大。与ON组相比，OF组的COP进程显示出更多的内侧偏移。但是OF组和NF组之间的COP参数没有显着差异。

意义

这项研究提供了充分的证据来支持对肥胖人群的前脚生物力学研究需要确定扁平足是对象筛查标准之一，以进行更可靠的结果而不产生混杂效应。