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Abstract
Background: It’s important to determine the plantar pressure distribution of school children by applying static and dynamic foot analyses using a pedobarography device. However, it’s difficult to obtain clear interpretations from results which can be explained by a large number of plantar pressure variables. The aim of this study is to use Principal Component Analysis (PCA) to predict main components for reducing the size of big data sets, provide a practical overview and minimize information loss on the subject of plantar pressure assessment in youths.
Methods: In total, 112 school children were included in the current study (average age 10.58 ± 1.27 years, body mass index 18.86 ± 4.33 kg / m2). During the research, a Sensor Medica Freemed pedobarography device was used to obtain plantar pressure data. Each foot was divided into six anatomical regions and evaluated. Global and regional plantar pressure distribution, load and surface areas, pressure time integrals, weight ratios and geometric foot properties were calculated.
Results: PCA yielded ten principal component (PC) that together account for 81.88% of the variation in the data set and represent new and distinct patterns. Thus, 137 variables affecting the subject were reduced to ten components.
Conclusions: Static and dynamic plantar pressure distribution, which is affected by many variables, can be reduced to ten components by PCA, making the research results more concise and understandable.
The number of trials required to obtain a reliable representation of the plantar pressure pattern is an important factor in the assessment of people with insensate feet or the use of plantar pressure data as a basis for fabrication of foot orthoses. Traditionally, the midgait method has been used for the collection of pressure data, but the large number of walking trials required by this method can increase the risk of injury to the plantar surface of the insensate foot. As a result, the two-step method of plantar pressure data collection has been advocated. The purpose of this investigation was to determine the degree of variability in regional plantar pressure measurements using the midgait and two-step methods of data collection. Plantar pressure data were collected from ten volunteers (five men and five women) between the ages of 20 and 35 years in 20 trials using both data-collection protocols. The results of the study indicate that three to five walking trials are needed to obtain reliable regional peak pressure and pressure-time integral values when the two-step data-collection protocol is used. Although either method can be used for pressure data collection, one method should be used consistently when repeated assessments are required.
Twelve subjects between the ages of 24 and 35 years walked barefoot over a pressure platform with the following insole materials placed directly on top of the platform: 1) PPT, 2) Spenco, and 3) Viscolas. Maximum vertical force, vertical force-time integral as well as maximum plantar pressure data were collected for the rearfoot, midfoot, and forefoot regions. The results were not significant for maximum vertical force and vertical force-time integral among the three insole materials when compared to barefoot-only walking. There was, however, a significant reduction in forefoot maximum plantar pressure among the three materials compared to barefoot-only walking. In the rearfoot region, a reduction in maximum plantar pressure was seen only with PPT and Spenco.
Ten subjects between the ages of 19 and 29 years walked and performed four aerobic movements over a force and pressure platform. Peak plantar pressure and peak vertical force data were collected three times on the dominant leg as each subject performed all of the five activities. Peak vertical forces acting on the lower extremities for the low impact aerobic movements were significantly less when compared with the high impact movements. As was expected, no differences were found in peak vertical forces between walking and the low impact aerobic movements. Peak plantar pressures for walking were not significantly different when compared with any of the four aerobic movements studied.
Plantar pressure-measurement technology is being increasingly used by podiatric physicians and surgeons in both clinical practice and research. The authors present normal reference-range values for peak pressure, mean pressure, and pressure-time integral obtained from 30 healthy subjects using a two-step recording technique and the EMED-SF system, as background for proposed clinical trials. Normative data of this type are essential for clinical practice in the comparison of plantar pressure-measurement values of individual patients with those of normal, asymptomatic feet.
A variety of plantar pressure and force measures were explored in 22 healthy individuals with excessive pronation. The measures were obtained while the subjects wore a thin-soled athletic shoe alone, a modified Root foot orthosis made from a neutral cast, and a flat noncast insole with a 6 degrees varus rearfoot post. The data obtained from subjects wearing the noncast insole differed only minimally from those obtained while they were wearing the shoe only. In contrast, the modified Root orthosis had a profound effect on foot function. Heel forces and pressures were reduced, and the rearfoot contact area was increased. Measures of force in the midfoot demonstrated substantial increases in load in this region, but the increase in area associated with the contoured device resulted in no increase in midfoot pressure measurements. Forefoot pressures were reduced both medially and laterally with the cast device in place.
INTRODUCTION AND OBJECTIVES: Healthy feet are important for overall health and well-being. Previous studies of older subjects showed that those with a lowered arch had an increased odds of having foot deformities, pain, and hyperpronation in gait. (1–3) No investigation to date has comprehensively characterized foot biomechanics in a large sample of healthy active young subjects.
METHODS: Foot structure, function, and arch height flexibility (AHF) were measured in 1,052 incoming cadets to the United States Military Academy. Based on the previously established standing arch height index (AHI), 70% of subjects exhibited planus foot structures. (4,5) To examine the effects of AHF on dynamic barefoot plantar pressure, 1,414 planus feet were further categorized by AHF. Those that fell within the highest and the lowest quintiles were defined as flexible and stiff AHF, respectively, while the middle 3 quintiles were categorized as referent.
RESULTS: Descriptive statistics and normality testing were performed using SPSS software version 22 (IBM, Chicago, IL, USA). A Generalized Linear Model with an identify link function was used to examine the effects of AHF category while accounting for potential dependence in bilateral data. The Wald Chi-square was calculated for each dependent variable with significance set at p < 0.05. Post hoc pairwise comparisons for all pairs were performed using the Generalized Chi Square test at P < 0.017.
CONCLUSIONS: A significant difference was found in Center of Pressure Excursion Index (CPEI) and Peak Pressure (PP). Post hoc pairwise comparisons showed a significant difference between flexible versus stiff AHF: those with flexible AHF exhibited reduced CPEI (greater hyperpronation) while those with stiff AHF showed elevated PP. Results suggest that, in addition to AHI, the arch flexibility may affect dynamic foot function. This was a part of larger study. Additional studies are needed to examine the effects of AHI and AHF on regional plantar loading and overuse injuries.
High plantar pressures contribute to skin breakdown in patients with diabetes mellitus and peripheral neuropathy. The primary purpose of this study was to determine the point during the stance phase of walking that corresponds with forefoot peak plantar pressures. Results indicate that peak plantar pressures occurred at 80% +/- 5% of the stance phase of gait in subjects with diabetes and transmetatarsal amputation, as well as in control subjects. Improved methods of footwear design or walking strategies proposed to patients should focus on the demands of the foot during the late stance phase of walking in order to increase available weightbearing area or to decrease forces, which will minimize plantar pressures and reduce trauma to the neuropathic foot.
