Gender differences in foot shape: a study of Chinese young adults

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.

Gender differences in footwear characteristics between half and full marathons in China: a cross-sectional survey

There are concerns about the risk of injuries caused by marathons in China. Since male and female runners have different injury risks, gender differences in running shoe functionality should be further complemented. A supervised questionnaire survey of 626 marathon runners was collected. The questionnaire was categorized into four sections: (1) participant profile, (2) importance of shoe properties, (3) functional evaluation of shoe properties and (4) importance ranking of shoe properties. The Mann-Whitney U test, Fisher's exact test of cross tabulation and Chi-square test, and two-way ANOVA were used to analyze the results of this survey. The significance level was set at P < 0.05. The full marathon participants were older than the half marathon participants. There was no gender difference in the importance of shoe features to elite runners. In addition, women are more concerned about upper elasticity and have higher requirements for running shoes than men. Women were more focused on injury prevention, while men were more focused on running performance. Heel cushioning was identified by all participants as the most important running shoe feature. There were no gender differences between elite players' demand for running shoes, but significant gender differences were found between genders at other running levels.

Methodological and statistical approaches for the assessment of foot shape using three-dimensional foot scanning: a scoping review

OBJECTIVE

The objectives of this study were to: (i) review and provide a narrative synthesis of three-dimensional (3D) foot surface scanning methodological and statistical analysis protocols, and (ii) develop a set of recommendations for standardising the reporting of 3D foot scanning approaches.

METHODS

A systematic search of the SCOPUS, ProQuest, and Web of Science databases were conducted to identify papers reporting 3D foot scanning protocols and analysis techniques. To be included, studies were required to be published in English, have more than ten participants, and involve the use of static 3D surface scans of the foot. Papers were excluded if they reported two-dimensional footprints only, 3D scans that did not include the medial arch, dynamic scans, or derived foot data from a full body scan.

RESULTS

The search yielded 78 relevant studies from 17 different countries. The available evidence showed a large variation in scanning protocols. The subcategories displaying the most variation included scanner specifications (model, type, accuracy, resolution, capture duration), scanning conditions (markers, weightbearing, number of scans), foot measurements and definitions used, and statistical analysis approaches. A 16-item checklist was developed to improve the consistency of reporting of future 3D scanning studies.

CONCLUSION

3D foot scanning methodological and statistical analysis protocol consistency and reporting has been lacking in the literature to date. Improved reporting of the included subcategories could assist in data pooling and facilitate collaboration between researchers. As a result, larger sample sizes and diversification of population groups could be obtained to vastly improve the quantification of foot shape and inform the development of orthotic and footwear interventions and products.

Firefighters' feet: Differences by sex and weight-bearing

Firefighters have reported their protective boots to be bulky and ill-fitting, which they believe restrict the lower body movement on the unpredictable fireground. This study used 3D foot scanning to compare the shape of firefighters' feet to the general population, the shape of female firefighters' feet to males, and the impact of the heavy fire gear on foot shape. The results found the foot breadth of firefighters was larger than the general population and the feet of female firefighters were slimmer than males. Furthermore, it revealed that the feet of firefighters became longer, wider, and flatter when bearing the weight of fire gear. Protective boots should be designed based on the foot shape and dimensions of the actual population, with consideration of sex differences and the impact of weight-bearing for their safety.

Foot deformation analysis with different load-bearing conditions to enhance diabetic footwear designs

In-depth analyses of foot surface measurements upon weight bearing are crucial to understand how the dorsal and plantar surfaces of the foot deform during motion to enhance the fit of footwear, which is particularly important for diabetic patients with stringent fit requirements to redistribute the plantar weight forces. This study analyzes diabetic foot deformations under 3 different weight bearing conditions (no weight bearing, half weight bearing, and 80% weight bearing) by using a novel foot scanning method that enables efficient scanning of the dorsal and plantar surfaces of the foot simultaneously. The feet of 48 patients with diabetes mellitus (DM) are scanned. With increased load on the feet, the width of the forefoot increases by 9.7%-10.4%, height of the midfoot decreases by 15.1%-18.2%, forefoot and midfoot rotate to the medial side by 16.9%-23.9% while the rearfoot rotates to the lateral side by 15.2% simultaneously, and the plantar of the foot increases contact with the floor by 11.4%-23.0%. Gender differences in foot shape are also found between males and females, males have a broader foot than females for the same foot length. Precise anthropometric information of foot changes and deformation therefore enables adequate foot protection, fit and comfort when designing footwear. This research contributes to shoe design considerations that focus on the deformation of the foot under different loads.

Relationship of Body Mass Index and Footprint Morphology to the Actual Height of the Medial Longitudinal Arch of the Foot

The medial longitudinal arch height of the foot is linked to individual characteristics such as sex and body mass index, and these characteristics have been shown to be associated with conditions such as flat feet. In this cross-sectional descriptive study, we examined the medial longitudinal arch morphology in an adult population to determine if there are differences related to sex and body mass index, and values were obtained for the foot posture index. Normalized anthropometric measurements and arch indices were calculated from footprints. Groups, defined by sex and body mass index, were compared, and the correlations between body mass index and the variables were determined. In the population studied (266 women and 177 men), significant differences between men and women for the foot posture index and normalized arch measurements were found. Analysis of the variables related to body mass index indicated there were significant differences in arch indices. Significant differences and positive correlations were also found between the arch index and body mass index for the left and right feet among the men and women studied. The results obtained allow us to reflect on and analyze whether the medial longitudinal arch morphology classification methods used in the clinical and research setting are adequate or whether the influence of factors such as body mass index can generate confusion.

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.

Foot Morphology in Chinese Adolescents Aged Between 13 to 18 Years Varies by Gender and Age

Background

We recently reported age and gender differences in foot shape and size in Chinese school children aged between 7–12 years. This study aimed to analyze age and gender differences in foot shape and size in Chinese adolescents aged between 13–18 years.

Material/Methods

The study included 1,252 adolescent boys and 1274 adolescent girls from seven regions in China. Twelve measurements of foot shape were recorded using a video filming system. One-way analysis of variance (ANOVA) compared the changes in the measurements with age. An independent t-test was used to analyze gender-associated differences in foot size and shape.

Results

In adolescent boys, foot length and width increased significantly at 13–14 years and heel width, arch height, and fifth metatarsal head height increased until 18 years (P<0.05). In adolescent girls, most foot measurements ceased to increase after 15 years, except for arch height. Adolescent boys showed significantly larger foot length, width, height, and girth compared with adolescent girls (P<0.05) (Cohen’s d effect size >0.8). Adolescent boys showed a significant increase in ball width and girth, and instep length and height compared with adolescent girls, who had a longer medial foot length and higher fifth metatarsal head height compared with adolescent boys (P<0.05) (Cohen’s d effect size >0.5).

Conclusions

Age and gender associated differences were found in foot measurements in Chinese adolescents, aged between 13–18 years. These differences should be considered by shoe manufacturers and when making clinical decisions about normal foot development.

Artificial neural networks in the selection of shoe lasts for people with mild diabetes

This research addressed the selection of shoe lasts for footwear design to help relieve the pain associated with diabetic neuropathy and foot ulcers. A reverse engineering (RE) technique was used to convert point clouds corresponding to scanned shoe lasts and diabetic foot data into stereo lithograph (STL) meshes. A slicing algorithm was developed and was used to find relevant girth features of diabetic foot and the shoe lasts. An artificial neural network, termed self-organizing map (SOM), classified 60 sets of shoe lasts into similar groups. Foot shapes of three mild diabetic patients were entered into the SOM feature categories to match with suitable shoe lasts. By conducting expert questionnaire analysis of the characteristic girths featured data with analytic hierarchy process (AHP), the weights of the girths were obtained. Grey relational analysis (GRA) was then used to calculate the correlation between foot girth and the corresponding range of shoe lasts. The most suitable shoe last for each patient with a mild diabetic foot can be determined by calculating the relative fitness function for each patient. By correlating diabetic foot with suitable shoe lasts, this study demonstrated an effective strategy for designing shoes for patients with mild diabetes, which can then be manufactured to meet customized requirements.

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.

Foot Morphology in Chinese School Children Varies by Sex and Age

Background

Knowledge of children’s foot shape is essential for podiatric healthcare and footwear design. Differences in foot shapes relative to sex and age were demonstrated among white children; however, no study has examined the foot characteristics of Asian children according to sex and age. This study aimed to analyze the age- and sex-associated differences in foot measurements in Chinese children.

Material/Methods

We recruited 1240 boys and 1303 girls from China as participants for the present study. Foot dimensions were recorded by a video filming system, and 12 foot-shape measurements were acquired. One-way ANOVA was used to calculated the changes in measurements with age for boys and girls. Scores were analyzed as raw and normalized to foot length using the independent-samples t test.

Results

Most measurements increased significantly at 7–8 and 8–9 years for girls and 8–9 and 10–11 years for boys. Arch height, instep length, and heel width showed greatest increases for both sexes ages 7–12 years (P<0.05). Sex differences in measurements mainly occurred at 8, 9, and 11 years. When we analyzed the normalized measurements of the same age children, instep length, heel width, ball girth, and instep girth were significantly different between boys and girls (P<0.05).

Conclusions

Sex- and age-associated differences were identified in the foot morphology of the Chinese school-aged children in this study. These differences should be considered when making clinical decisions about normal foot development and manufacturing shoes for Chinese school children.

Study on the foot shape characteristics of the elderly in China

BACKGROUND

With aging, the feet of the elderly above 60 years old in China present degenerative changes, deformities, and diseases, which significantly affect their daily activities.

OBJECTIVES

The authors aimed to study the morphological characteristics of the feet and identify the foot type according to size (length and width) and defect characteristics of elderly feet in China.

METHODS

A convenient sample of 1000 subjects above 60 years old was recruited mainly in the regions of Shanghai, Shaanxi, Henan, Hebei, and Sichuan in China. Foot images were collected, and 800 (male 398, female 402) valid questionnaires were recovered. A total of 800 elderly subjects as the test group were invited to measure their foot sizes by means of a Footprint Collector (Tong Yuan Tang Health Management Limited, Qingdao in Shandong province). The foot type of the elderly was compared with that of the general adult Chinese population as the control group using the t-test for independent samples.

RESULTS

Hallux valgus (46.9%) and flat foot (50.0%) were the most common foot shape deformities. The most frequent foot diseases were foot scaling (91.2%) and calluses (96.3%). The medial width of the first metatarsal-toe joint of the elderly was significantly higher (elderly female, 44.95±4.86mm; elderly male, 48.55±4.94mm) than that of the general adult population (adult female, 40.18±3.43mm; adult male, 43.22±3.20mm) (p<0.01).

CONCLUSION

The foot length of the elderly was not significantly different from that of the general adult Chinese population. The width of the first metatarsal-toe joint in the forefoot of the elderly was significantly higher than that of the general adult Chinese population, which was consistent with the result that a high proportion of elderly subjects presented hallux valgus.

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 deformation during walking: differences between static and dynamic 3D foot morphology in developing feet

The complex functions of feet require a specific composition, which is progressively achieved by developmental processes. This development should take place without being affected by footwear. The aim of this study is to evaluate differences between static and dynamic foot morphology in developing feet. Feet of 2554 participants (6-16 years) were recorded using a new scanner system (DynaScan4D). Each foot was recorded in static half and full weight-bearing and during walking. Several foot measures corresponding to those used in last construction were calculated. The differences were identified by one-way ANOVA and paired Student's t-test. Static and dynamic values of each foot measure must be considered to improve the fit of footwear. In particular, footwear must account for the increase of forefoot width and the decrease of midfoot girth. Furthermore, the toe box should have a more rounded shape. The findings are important for the construction of footwear for developing feet.