Sex-related differences in foot shape of adult Caucasians--a follow-up study focusing on long and short feet

Development of a footwear sizing system for diabetic feet

The number of diabetic patients is increasing rapidly who have vulnerable feet and might be easily affected by different adversities. Since there is no available footwear sizing system for diabetic patients, manufacturers produce diabetic footwear of different sizes and fittings based on other available footwear sizing systems, which may result in inappropriate fitting. To get footwear with proper fittings, diabetic patients may go for customized or bespoke footwear based on their foot conditions, which is very costly. This study attempts to explore the foot complications of diabetic patients and categorize their feet to create a new sizing system using foot measurements from 102 male diabetic patients based on three dimensions of human feet, namely foot length, ball girth, and instep circumference. K-means data clustering is followed to categorize the data into three broad groups, namely small, medium, and large groups for footwear sizing. The developed footwear sizing system uses a sizing interval of 8 mm and a fitting interval of 6 mm. This study suggests a total of 11 sizes along with 24 different fittings for the footwear manufacturers for producing diabetic footwear. This newly developed footwear sizing system has a total of 79.41 % coverage where there are 10, 10, and 4 fittings in the small, medium, and large groups, respectively. The proposed footwear sizing system can help footwear manufacturers understand the proper size and fit of diabetic patients' feet so that they can make appropriate footwear for diabetic patients economically.

Foot shape assessment techniques for orthotic and footwear applications: a methodological literature review

Introduction

Foot shape assessment is important to characterise the complex shape of a foot, which is in turn essential for accurate design of foot orthoses and footwear, as well as quantification of foot deformities (e.g., hallux valgus). Numerous approaches have been described over the past few decades to evaluate foot shape for orthotic and footwear purposes, as well as for investigating how one's habits and personal characteristics influence the foot shape. This paper presents the developments reported in the literature for foot shape assessment.

Method

In particular, we focus on four main dimensions common to any foot assessment: (a) the choice of measurements to collect, (b) how objective these measurement procedures are, (c) how the foot measurements are analyzed, and (d) other common characteristics that can impact foot shape analysis.

Results

For each dimension, we summarize the most commonly used techniques and identify additional considerations that need to be made to achieve a reliable foot shape assessment.

Discussion

We present how different choices along these two dimensions impact the resulting foot assessment, and discuss possible improvements in the field of foot shape assessment.

Do foot type classifications differ between male and female netball players? A cluster analysis

We must better understand the foot type classifications of netball players to develop sex and size-specific shoe lasts. Five hundred and two representative-level netball players (n = 251 male; n = 251 female) had their feet three-dimensionally scanned. A validated MATLAB code was used to extract six different foot measurements from these scans automatically. We then used a two-step cluster analysis and chi-squared tests to classify foot types and determine the effect of sex on each cluster, respectively. Five foot types were identified (Extra long-and-wide, Long-and-wide, Flat, Tapered and Short-and-narrow), with sex significantly affecting foot type classification. The feet of players wearing smaller shoe sizes were often Short-and-narrow and Tapered, whereas the feet of players wearing larger sizes tended to be more Extra long-and-wide and Long-and-wide. These results highlight that netball players have a wide variety of foot types; manufacturers should use these data to develop future grading systems to improve the fit and functionality of netball-specific footwear.

Do the feet of male and female netball players differ in shape? Implications for shoe design

A large proportion of netball players suffer foot-related problems and pain and are dissatisfied with current netball-specific footwear. To improve the fit and functionality of netball-specific shoes, we must understand the shape of these players' feet and determine whether any sex differences exist. Five hundred and two representative-level netball players (n = 251 male; n = 251 female) had their feet three-dimensionally scanned. We then used a validated MATLAB code to automatically extract 10 measurements to characterise each participant's foot shape. Differences between men and women for the absolute values and those normalised to foot length and stature were identified using independent samples t-tests with a Bonferroni adjusted alpha level. The size and shape of male netball players' feet differed significantly from their female counterparts. Males had significantly larger absolute and normalised foot measurements than females, notably at the ball of the foot, heel and instep (p < 0.001). Netball shoe manufacturers should develop unique lasts for each sex and foot size and should offer a more extensive range of shoe lengths and widths to netball players. Such considerations will help optimise shoe fit and comfort and, in turn, reduce foot-related problems and pain associated with ill-fitting footwear.

Correlation analysis between body mass index and foot length in Chinese adolescents: a regional study

This study aims to analyse the relationship between body mass index and foot length in Chinese adolescents and to provide theoretical guidance for preventing a flat foot in Chinese adolescents. This study recruited 1477 students aged 14-23 years. The participants' height, weight, and body mass index were measured, as well as baseline data, including age, gender and foot length. Differences in foot length (bilateral) and flat foot distribution were statistically significant except for the normal foot and high arch foot distribution based on different body mass index groups. Linear correlation analysis demonstrated that body height, weight and body mass index were positively correlated with bilateral foot length regardless of gender. Body mass index acted as a risk factor for flat foot (bilateral) through disordered multi-classification logistic regression analysis. Body mass index was positively correlated with left and right foot length regardless of gender and acted as a risk factor for a flat foot in Chinese adolescents. Practitioner summary: Significant differences exist in the anthropometric data of various races and ethnic groups. The study was investigated in the form of a cross-sectional study. BMI was positively correlated with bilateral foot length and acted as a risk factor for a flat foot in Chinese adolescents.

Effect of Sex-Specific Running Shoes on Female Recreational Runners

Alterations in running shoe design have been studied and used in the prevention of injury and enhancement of performance allowing running shoe companies to market to a variety of runners based on skill level, foot-strike pattern, and even sex. These alterations have been shown to affect biomechanical and physiological variables associated with running. Some shoe companies have designed shoes specifically for biological female runners due to the morphological differences found between male and female feet. The purpose of this study is to determine if sex-specific running shoes can alter female runner biomechanics or physiology. Female runners were asked to run in the male and female models of the Altra Torin 4 Plush shoe to determine if there were differences in ground reaction forces (GRFs), sagittal plane joint angles and moments, oxygen consumption (VO2), respiratory exchange ratio (RER), and perceived level of comfort while running; There were no significant differences in GRFs, sagittal joint angles and moments, VO2, RER, or perceived comfort; There were no differences in measured biomechanical or physiological variables between the female and male version of the shoes suggesting that the alterations made to the female-specific shoe do not provide any additional benefit to female recreational runners.

Stature estimation from various three-dimensional anthropometric foot measurements of Taiwanese female population

Predicting a victim's stature from a dismembered body or human remains is a challenge in forensic practice. Lower extremity dimensions, such as the foot, are essential measurements for stature estimation. However, there is no available information on stature prediction generated from Taiwanese female foot measurements in the forensic science field. Hence, this study aims to investigate the correlations between various foot dimensions and stature and develop population-specific stature-prediction equations for Taiwanese females. Bilateral data of 12 foot dimensions were collected from 1058 females aged from 18 to 59 years using three-dimensional scanning. A pairedt-test is performed to evaluate bilateral differences, and linear and stepwise regression analyses are performed to generate stature predictions. The results indicate significant bilateral differences in the majority of the foot measurements. All measurements are positively correlated with stature (p < .05). Higher correlation coefficients with stature are observed in length-related foot dimensions, followed by girth- and breadth-related dimensions. The foot length on both sides is selected as an accurate and reliable parameter to conduct linear stature-predicting regression for Taiwanese females because it exhibits the highest explanation rate (right: 54.1%; left: 50.8%) and lowest estimating standard error (right: 3.883 cm, left: 4.020 cm) among the 12 foot measurements. Based on the results of the stepwise regression analysis, several stature-prediction equations consisting of various foot measurements are established. The findings of this study can provide helpful information for predicting the stature of Taiwanese females from fragmentary foot remains.

Differences in foot dimensions between children and adolescents with and without Down syndrome

PURPOSE

This study compared the differences in foot dimensions between children with and without Down syndrome using three-dimensional (3D) foot scans.

METHODS

51 children with and 51 children without Down syndrome had a 3D scan taken of their right foot to compare the absolute and normalised (for height or foot length) measurements.

RESULTS

Normalised foot length was shorter in children with Down syndrome (MD -11.62 mm, 95% CI -15.06 to -8.18, p < 0.001). When normalised for foot length, ball of foot length (MD 2.87 mm, 95% CI 1.17 to 4.58, p = 0.001), diagonal and horizontal foot width (MD 3.65 mm, 95% CI 1.65 to 5.66, p < 0.001; MD 4.80 mm, 95% CI 2.88 to 6.72, p < 0.001, respectively), ball and instep girth (MD 10.60 mm, 95% CI 5.96 to 15.25, p < 0.001; MD 7.92 mm, 95% CI 3.02 to 12.82, p = 0.002, respectively) and fifth toe height (MD 3.14 mm, 95% CI 2.22 to 4.07, p < 0.001) were greater in children with Down syndrome.

CONCLUSIONS

Children with Down syndrome have shorter, wider feet with greater girth and fifthtoe height measurements relative to children without Down syndrome. These findings have implications for footwear fit and the manufacturing of population-specific footwear.IMPLICATIONS FOR REHABILITATIONFootwear-fitting issues arise as a result of the unique foot shape of children with Down syndrome.There are substantial variations in the foot shape of children with and without Down syndrome.Children with Down syndrome require wider, deeper footwear at a given length to accommodate their foot dimensions.These findings have implications for the manufacturing of population-specific footwear.

The Influence of Gender, Age, and Body Mass Index on Arch Height and Arch Stiffness

Arch structure and arch function play an important role in maintaining balance, bearing body weight, and absorbing ground reaction forces. However, arch structure and arch function are known to vary extensively and may be affected by factors such as gender, age, and obesity. Therefore, the purpose of this study was to examine the influence of gender, age, and body mass index (BMI) on arch height and arch stiffness. A total of 173 participants (aged 57.60 ± 11.19 years, mean BMI 25.12 ± 3.93 kg/m²) participated in this cross-sectional study. A 3-dimensional laser scanner was used to measure foot structure information in each subject, from which arch height and arch stiffness were calculated. The results showed that women had low-arched feet compared with men (p = .001), and no arch stiffness difference was found. Older individuals tended to have a stiffer arch than middle-aged and younger individuals (p < .05), and no arch height difference was found. BMI had an impact on arch height (p < .05) but not arch stiffness. Finally, a weak positive relationship existed between arch height and arch stiffness (r = 0.32, p < .01). The findings suggest that gender, age, and obesity have a certain impact on arch structure and arch stiffness. Figuring out the relationship between these factors and arch structure may be helpful in understanding the bases of foot deformity and foot dysfunction.

A data-driven classification of 3D foot types by archetypal shapes based on landmarks

The taxonomy of foot shapes or other parts of the body is important, especially for design purposes. We propose a methodology based on archetypoid analysis (ADA) that overcomes the weaknesses of previous methodologies used to establish typologies. ADA is an objective, data-driven methodology that seeks extreme patterns, the archetypal profiles in the data. ADA also explains the data as percentages of the archetypal patterns, which makes this technique understandable and accessible even for non-experts. Clustering techniques are usually considered for establishing taxonomies, but we will show that finding the purest or most extreme patterns is more appropriate than using the central points returned by clustering techniques. We apply the methodology to an anthropometric database of 775 3D right foot scans representing the Spanish adult female and male population for footwear design. Each foot is described by a 5626 × 3 configuration matrix of landmarks. No multivariate features are used for establishing the taxonomy, but all the information gathered from the 3D scanning is employed. We use ADA for shapes described by landmarks. Women’s and men’s feet are analyzed separately. We have analyzed 3 archetypal feet for both men and women. These archetypal feet could not have been recovered using multivariate techniques.

Analysis of 1.2 million foot scans from North America, Europe and Asia

For decades, footwear brands have developed products using outdated methods and measurements, working with limited insight into the foot shapes and dimensions of their target customers. The integration of 3D scanning technology into footwear retail stores has made it possible for this research to analyze a database containing a large number of male and female 3D foot scans collected across North America, Europe, and Asia. Foot scans were classified into length classes with 5mm length increments; mean width, instep height, and heel width were calculated for each length class. This study confirms the existence of many statistically significant differences in mean foot measurements amongst the regions and between the sexes, and a large dispersion of foot measurements within each group of customers. Therefore, shoes should be developed separately for each group, region, and sex, and at least 3 shoe widths per length class are required to provide a proper fit for 90% of customers. Beyond this, our analysis asserts that a shoe designed for a single group will fit a different segment of the population in another group, and that existing last grading tables should be updated to reflect the foot dimensions of current consumers.

A review of the methodology and applications of anthropometry in ergonomics and product design

Anthropometry is a key element of ergonomic studies for addressing the problem of fitting the tasks/products to user characteristics, but there is a gap between anthropometric data and their application for designing ergonomic products and environments. This research was conducted to review the literature on the methodology and applications of anthropometry for the ergonomic design of products and environments, and to identify where further research is needed to improve its application and evaluation protocols. One hundred and sixteen papers meeting the inclusion criteria were reviewed. Although a number of anthropometric investigations have been conducted to improve the design of products/environments for different users, further research seems to be necessary, particularly for special groups, such as children, the elderly and people with disabilities. Different anthropometric measurement methods/techniques and fitting criteria are discussed regarding their applicability for various design applications. This review also highlights methodological issues (sampling considerations and prototype evaluation and testing) that should be considered in future research to ensure a user-centred approach of the design process. Practitioner Summary: A literature review was conducted on the methodology and applications of anthropometry for the ergonomic design of products/environments. This review emphasises the need for anthropometric research to design for special groups, such as children, the elderly and people with disabilities, and methodological issues that should be considered in future research. Abbreviations: 1D: one-dimensional; 2D: two-dimensional; 3D: three-dimensional; HF/E: Human Factors/Ergonomics; PCA: Principal Components Analysis; CA: Cluster Analysis; DHM: Digital Human Modelling.

A comparative study of standing fleshed foot and walking and jumping bare footprint measurements

Approximating true fleshed foot length and forefoot width from crime scene footprints is primarily based on anecdotal observations and fails to consider effects of different dynamic activities on footprint morphology. A literature search revealed numerous variables influencing footprint formation including whether the print was formed statically or dynamically. The aim of this study was to investigate if length and width measurements of the fleshed foot differ to the same measurements collected from walking and jumping footprints. Measurements of standing right foot length and forefoot width were collected from thirteen participants. Walking and jumping right footprints were then obtained using an Inkless Shoeprint Kit and digitally measured with GNU Image Manipulation Programme. Descriptive analysis compared standing fleshed foot length and forefoot width against the same measurements taken from walking and jumping footprints with and without ghosting. Results suggested walking footprint length with ghosting (x¯ = 268.61 mm) was greater than standing fleshed foot length (x¯ = 264.3 mm) and jumping footprint length with ghosting (x¯ = 261.57 mm). However, standing fleshed foot length was found to be greater than walking (x¯ = 254.85 mm) or jumping (x¯ = 255.63 mm) footprint lengths without ghosting. Forefoot widths showed standing fleshed foot width (x¯ = 105.66 mm) was greater than walking (x¯ = 95.63 mm) or jumping (x¯ = 98.03 mm) footprint widths. This study identifies variation in measurements of the standing fleshed foot and those of walking and jumping footprints, including variability between different dynamic states.

Taiwanese adult foot shape classification using 3D scanning data

This study classifies the foot shapes of Taiwanese using 3D foot scanning data from 2000 males and 1000 females. Nine foot dimensions relative to foot length and absolute measures in the common foot length categories were applied to compare the gender differences. Using foot breadth in % foot length (% FL), ball of foot length in % FL and arch height in % FL as feature parameters, three foot shape types for males and females can be classified. Significant gender differences were found in seven of the nine foot dimensions. Females had greater ball of foot length than males (0.2% FL). When comparing feet of the same foot length, males had greater breadth, girth and height dimensions than females, except for toe height. In addition, ethnic differences in foot shape were also observed. The findings can provide very useful information for building gender-specific shoe lasts and designing footwear insoles.

PRACTITIONER SUMMARY

3D foot scanning data of 2000 males and 1000 females were classified into three different footshapes for males and females, respectively. Gender and ethnic differences on foot shape were also compared. The finding scan provide very useful information for gender-specific shoe last design and footwear production.

Foot morphology in Spanish school children according to sex and age

The aim of this study was to analyse the differences in foot dimensions in a sample of Spanish school-aged children. A total of 497 boys and 534 girls from Spain participated in the study. Measurements of both feet were obtained using a 3D foot digitiser, and shoe sizes were recorded and then estimated based on foot length measurements. The variations in foot measurements underwent a gradual increase with age in both boys and girls. Gender differences appeared at the age of 8-9 years, when the girls in the sample were found to wear smaller shoes than those they should have worn. Most foot dimensions begin to differ between boys and girls at the age of 8 years. The girls in the sample studied used footwear that was too small for their foot length, probably because they looked for a better width fit.

Inter-joint sharing of total support moments in the lower extremities during gait in narrow-heeled shoes of different heights

The study aimed to investigate the influence of the base and height of shoe heels on the total support moment (Ms) and individual joint contributions during gait. Fifteen healthy females walked barefoot and with narrow-heeled shoes (heel heights: 3.9, 6.3 and 7.3 cm) while kinematic and kinetic data were measured. Compared with the barefoot condition, the subjects maintained unaltered Ms in the sagittal plane in shod conditions. This was achieved by increasing the knee extensor moment to compensate for the diminished ankle plantarflexor moments in medium and high heel conditions. In the frontal plane, subjects in shod conditions had to sustain an increased Ms for balance control during late single-leg stance with increased knee abductor and ankle pronator moments as a result of the reduced base of the heels. The results will be helpful for future shoe designs to reduce fall risks and prevent relevant musculoskeletal problems.

Load distribution to minimise pressure-related pain on foot: a model

The optimal force distribution to minimise pain or discomfort at the foot-shoe interface is still not known. Most shoe-related products attempt to distribute the load uniformly without much consideration to the bony and soft tissue regions. An experiment was conducted to first determine the pressure pain threshold (PPT) and tissue deformation on the plantar surface of the foot. Circular probes of areas 0.5, 1.0 and 2.0 cm(2) at indentation speeds of 0.5, 1 and 2 mm/s showed that PPT depends on the location stimulated, area of stimulation and the indentation speed. The results also showed that tissue stiffness is quite low for small deformations ( < 4 mm), but significantly higher at large deformations (>4 mm). The stiffness at the larger deformation region was positively correlated with PPT (r = 0.63, p < 0.001). The data were further used to develop a model with PPT, deformation and stimulated area.

PRACTITIONER SUMMARY

Pressure at which there is an onset of pain is higher when a larger area of soft tissue is stimulated. Bony areas may be better suited to bear load on smaller areas to minimise pressure-related pain. Thus, manipulating supporting surface stiffness and surface contours can help minimise pain.