Dimensional differences for evaluating the quality of footwear fit

Mathematical model for footwear upper material consumption estimation

Appropriate material consumption estimation since the design phase for footwear fabrication is a vital issue as material costs account for a sizeable portion of the overall production cost of a pair of shoes. This paper presents a mathematical model to predict the calculation of footwear upper material consumption to improve the utilization ratio of materials through a suitable nesting map onto leather. The proposed model concentrates on the two-dimensional geometry of footwear components and the application of rich mathematical concepts. The model reflects the outlines of individual footwear components while determining the area using definite integral calculus. Five distinct rotational kinds are applied for component arrangements that correlate to the physiognomy of leather because nesting onto the leather is intractable. The simple concept of a minimal-area polygonal enclosure is applied to maximize material utilization with minimum waste. Finally, the model was verified for four consecutive Oxford footwear sizes by comparing actual upper material consumption with predicted upper material consumption. The noble contribution of this analysis is to use ImageJ software to compute upper material consumption in real case analysis through image processing techniques and separate estimation of wastes, especially the fourth waste. The results of the comparison study show that the proposed model can reduce average material requirements by 2.06 %. This minimization of waste could be beneficial in terms of economic and environmental sustainability. Therefore, this study can be applied to estimate more accurately the amount of upper material required for footwear fabrication and support better utilization of material in the footwear industry.

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.

Sexual dimorphism and determination using foot outlines, foot print angles, and foot indices

Sex determination is one of the fundamental procedures in the forensic investigation during personal identification. Foot dimensions, prints, indices, and angles are assessment tools used by podiatrists and forensic anthropologists. The arch index remains a tool for clinical evaluation of the incidence of pes planus by clinicians. This cross-sectional study was performed to investigate sexual dimorphism and discriminate sex using foot and footprint dimensions, foot angles, and foot indices among the Ebira ethnic group of Nigeria. Bilateral foot outlines and prints were obtained from 317 females and 283 males using a digital Vernier caliper, improvised footpad, and A4 paper. The results revealed that in the right foot and print, the males' bare right foot length (BRFL), bare right foot breadth (BRFB), right arch index (RAI), right Chippaux-Smirak index (RCSI), right footprint angle (RFPA), right ball angle (RBA), and all the measurements of the corresponding toes in the prints are significantly greater (p < 0.05) than the females. The same trend was also observed in the left footprint except for the left ball angle (LBA). The stepwise, binary logistics regression model for sex determination showed that bare left foot breadth (BLFB) and bare right foot length (BRFL) were the single best predictors of sex with an accuracy of 72.5% and 71.7% accuracy. Other foot variables marginally increased the percentage accuracy at each step. The receiver operating characteristic (ROC) curve analysis confirmed the sexing potential of the bare left foot breadth and bare right foot length to be 79%. Sexual dimorphism exists in all the foot dimensions, arch indices, Chippaux-Smirak indices, footprint angles, and ball angles, except the left ball angle. The sexual dimorphism in the foot variables forms the basis of sex determination, with left foot breadth and right foot length as the best sex predictors. Therefore, 25 cm can be regarded as the cut-off point for foot length and 9 cm as the cut-off point for foot breadth among this tribe.

Modelling the thermal microenvironment of footwear subjected to forced ventilation

In this paper, we develop a mathematical model of the thermal microenvironment in footwear that considers forced ventilation of the footwear cavity. The developed model was validated using a newly developed thermal foot-manikin system and the results show that the model effectively predicts the total dry thermal insulation of footwear under various dynamic conditions. The footwear cavity model is then integrated with a thermoregulation model, and the integrated model effectively predicts changes in foot skin temperature resulting from forced ventilation (0-90 L/min). At an air temperature of 26.4 °C and a foot thermal comfort temperature of 32.2 °C, the required minimum ventilation rate was found to be 5.4-24.6 L/min, which corresponds to a total static thermal insulation of footwear of 0.10-0.20 m2·K·W-1. This indicates that ventilation can adequately control the thermal microenvironment of the footwear cavity, thereby maintaining foot thermal comfort. Practitioner summary: An adverse footwear thermal microenvironment results in foot thermal discomfort and foot hygiene problems. We hypothesise that forced ventilation may enable thermal control of footwear microenvironments. A mathematical model was developed which can determine the forced ventilation rate required in a given type of footwear to create foot thermal comfort.

Are habitually barefoot children compelled to wear ill-fitting school shoes? A cross-sectional study

Background

Research shows that ill-fitting shoes can negatively impact the development of the pediatric foot, in a very direct manner. The primary aim of the study was to determine if the dimensions of available prescribed school shoes fit the foot dimensions of habitually barefoot South African children and adolescents.

Methods

A cross-sectional observational study was conducted where static standing foot measurements of children and adolescents from urban and rural schools were obtained with a mobile caliper. The maximum heel-toe-length and foot width with an added 10 mm toe- and width fit allowance to each participant, were compared to the corresponding school shoe length and shoe width available in retail. A mixed model ANOVA was used to compare foot dimensions between gender, age and side.

Results

Six hundred and ninety-eight school children (N = 698) (431 girls; 267 boys; average age 10.86 years, SD = 2.55) were participants. A total of seventy-seven (N = 77) black coloured prescribed school shoes currently available in retail ranging from different styles and brands were measured. Results show that, comparing the shoe length and maximum heel-toe-length of participants, as well as taking 10 mm toe allowance into account, fifty-nine percent (59%) of children wore shoes that were not the correct length. With regards to the shoe width and the added 10 mm of width fit allowance, ninety-eight percent (98%) of the shoes worn by participants were too narrow for their feet.

Conclusions

Results confirmed that school shoes currently available in retail, are not suited for the habitually barefoot population studied. It is recommended that the shoe manufacturing industry should consider the shoe width of school shoes for children and adolescents in habitually barefoot populations to avoid the long-term negative effect of ill-fitting shoes on the pediatric foot.

Safety footwear: A survey of end-users

This paper presents the results of an extensive survey concerning the experience of safety footwear end-users. Safety footwear has been in widespread use across many industries worldwide since the 1970s, and has become an essential part of industrial Personal Protective Equipment. The number of women entering predominantly male industrial environments, and requiring safety footwear is rising, and this is accompanied by anecdotal reports of ill-fitting and uncomfortable footwear. This research proactively compares the opinions of women and men regarding their experience of safety footwear. A systematically designed survey aims to substantiate previously anecdotal knowledge around safety footwear, including key drivers for end-user purchases, wear habits and comfort issues (establishing any differences between women and men). Chi-squared testing was used to assess statistical significance and ensure robustness of findings. The responses and resulting analysis confirmed that comfort and fit were key drivers for all end users; women and men have different wear habits (women wear their safety footwear less frequently and for shorter periods of time than men - likely due to the reported comfort issues); a significant proportion of women (60%) found their safety footwear less comfortable than their regular footwear, however, 45% of men also reported the same, which has not been reported anecdotally. In general, the users of safety footwear accepted a level of discomfort in at least one area of the foot before deeming footwear 'uncomfortable'. The significant analysis performed on the captured data has, to the authors knowledge, never before been undertaken for this breadth of industry, age and gender with 632 responses received. This makes it the largest study of this field to date.

Footprint Curvature in Spanish Women: Implications for Footwear Fit

The incorrect adjustment of footwear produces alterations in the foot that affect quality of life. The usual measurements for shoe design are lengths, widths and girths, but these measures are insufficient. The foot presents an angle between the forefoot and the rearfoot in the transverse plane, which is associated with foot pronation, hallux valgus and metatarsus adductus. Here, we aimed at identifying the groups formed by the angulations between the forefoot and rearfoot using a sample of footprints from 102 Spanish women. The angle between the forefoot and rearfoot was measured according to the method described by Bunch. A cluster analysis was performed using the K-means algorithm. Footprints were grouped into three types: curved, semi-curved and straight, according to the degrees of angulation between the forefoot and rearfoot. There is great variability in the morphology of the foot. Based on our findings, to achieve a better footwear fit, we propose the manufacture of three types of lasts with different curvatures.

Determination of optimal shoe fitting for children tennis players: Effects of inner-shoe volume and upper stiffness

The purpose of this study was to determine the optimal inner-shoe volume for children tennis players. Sixteen participants, aged from 8 to 12 years old assessed comfort of 6 shoes, which were a combination of 3 lasts (thin, medium and wide) and 2 upper constructions (flexible and stiff), while a sock equipped with textile sensors was measuring the pressure applied on their foot. The thin last was based on the proportion of an adult last. The widest shoes produced the lowest pressure on the 1st and 5th metatarsal heads, the medial midfoot and the medial and lateral heel (p < 0.05), whilst they were perceived the most comfortable for the 3rd and 5th metatarsal heads, the 5th metatarsal base and the medial and lateral heel (p < 0.05). These outcomes indicated that footwear manufacturers should design wider shoes for children than for adults.

Everyday footwear: An overview of what we know and what we should know on ill-fitting footwear and associated pain and pathology

Footwear has been used to protect feet for millennia with socially exclusive population adopting stylish and fashionable shoes with expensive materials. In terms of historic timeline, only more recently footwear has been worn by all classes in the western world as an integral part of their apparel. Traditionally, footwear has been constructed from natural materials, mainly leather, but has recently benefitted from the flexibility that technology has provided with a plethora materials and new design innovations. Although it has expanded the availability for a variety of consumers, the choice and fit continue to be problematic with many individuals wearing shoes that are ill-fitting. Provision of specific footwear advice for problem feet is poorly evidenced and is heavily practitioner dependant limiting its efficacy. There is limited understanding as to the changes that can occur from regularly wearing footwear that is unsuitable in shape, style and construction which is referred to as ill-fitting. Current research on the effect that everyday footwear has on foot function and pain focuses mainly on women's shoes, particularly high heels. Defining what is a good fitting shoe, that does not damage the foot or mechanics of walking, may need to be individualised, but best fit is based on loose historical parameters rather than research evidence. The aim of this overview is to highlight aspects of current research, establishing what is known about the effect's shoes have on the feet as well as exploring the mythology around footwear fit and advice that is often historical in nature.

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.

How do we fit underground coal mining work boots?

Acceptable footwear fit, particularly width, is subjective and vaguely quantified. Proper shoe fit is important because it affects both comfort and the potential to prevent injury. Although mismatches between the feet of underground coal miners and their internal boot dimensions are known, no research has been undertaken to determine the impact of these mismatches on worker perceptions of fit, comfort and pain. This study aimed to quantitatively assess mining work boot fit relative to underground coal miners' subjectively rated work boot fit and comfort, reported foot problems, lower limb pain and lower back pain in order to develop evidence-based work boot fit recommendations. Traditional footwear fitting methods based predominantly on foot length are insufficient for underground coal mining-specific footwear. Instead, fit at the heel, instep and forefoot must be considered when fitting underground coal mining work boots, in conjunction with the traditional length measurement.Practitioner summary: Underground coal miners report their work boots fit but are uncomfortable. This study assessed actual fit relative to perceived fit, comfort, foot problems, lower limb pain and lower back pain of 197 miners. Fit at the heel, instep and forefoot must be considered when fitting mining work boots.

Incorrectly fitted footwear, foot pain and foot disorders: a systematic search and narrative review of the literature

Background

Correct footwear fitting is acknowledged as being vitally important, as incorrectly fitted footwear has been linked to foot pathology. The aim of this narrative review was to determine the prevalence of incorrectly fitted footwear and to examine the association between incorrectly fitted footwear, foot pain and foot disorders.

Methods

A database search of Ovid MEDLINE and CINAHL yielded 1,681 citations for title and abstract review. Eighteen articles were included. Findings were summarised under the categories of (i) children, (ii) adults, (ii) older people, (iii) people with diabetes and (iii) occupation- or activity-specific footwear. Differences in footwear fitting between sexes were also explored.

Results

Between 63 and 72% of participants were wearing shoes that did not accommodate either width or length dimensions of their feet. There was also evidence that incorrect footwear fitting was associated with foot pain and foot disorders such as lesser toe deformity, corns and calluses. Specific participant groups, such as children with Down syndrome and older people and people with diabetes were more likely to wear shoes that were too narrow (between 46 and 81%).

Conclusion

A large proportion of the population wear incorrectly sized footwear, which is associated with foot pain and foot disorders. Greater emphasis should be placed on both footwear fitting education and the provision of an appropriately large selection of shoes that can accommodate the variation in foot morphology among the population, particularly in relation to foot width.

Development of a Footwear Sizing System in the National Football League

Context:

Footwear performance and injury mitigation may be compromised if the footwear is not properly sized for an athlete. Additionally, poor fit may result in discomfort and foot injury such as fifth metatarsal stress fracture, foot deformities, turf toe, and blisters. Current footwear fitting methods consist of foot length and width measurements, which may not properly describe the shape of the individual foot, correlated with shoe size descriptors that are not standardized. Footwear manufacturers employ a range of sizing rubrics, which introduces shoe size and shape variability between and even within footwear companies. This article describes the synthesis of literature to inform the development and deployment of an objective footwear fitting system in the National Football League (NFL). The process may inform athletic footwear fitting at other levels of play and in other sports.

Evidence Acquisition:

Literature related to footwear fitting, sizing, and foot scanning from 1980 through 2017 was compiled using electronic databases. Reference lists of articles were examined for additional relevant studies. Sixty-five sources are included in this descriptive review.

Study Type:

Descriptive review.

Level of Evidence:

Level 5.

Results:

Current methods of footwear fitting and variability in the size and shape of athletic footwear complicate proper fitting of footwear to athletes. An objective measurement and recommendation system that can match the 3-dimensional shape of an athlete’s foot to the internal shape of available shoe models can provide important guidance for footwear selection. One such system has been deployed in the NFL.

Conclusion:

An objective footwear fitting system based on 3-dimensional shape matching of feet and shoes can facilitate the selection of footwear that properly fits an athlete’s foot.

The three-dimensional shapes of underground coal miners' feet do not match the internal dimensions of their work boots

Mining work boots provide an interface between the foot and the ground, protecting and supporting miners' feet during lengthy coal mining shifts. Although underground coal miners report the fit of their work boots as reasonable to good, they frequently rate their boots as uncomfortable, suggesting that there is a mismatch between the shape of their feet and their boots. This study aimed to identify whether dimensions derived from the three-dimensional scans of 208 underground coal miners' feet (age 38.3 ± 9.8 years) differed from the internal dimensions of their work boots. The results revealed underground coal miners wore boots that were substantially longer than their feet, possibly because boots available in their correct length were too narrow. It is recommended boot manufacturers reassess the algorithms used to create boot lasts, focusing on adjusting boot circumference at the instep and heel relative to increases in foot length. Practitioner Summary: Fit and comfort ratings suggest a mismatch between the shape of underground coal miners' feet and their boots exists. This study examined whether three-dimensional scans of 208 miners' feet differed from their boot internal dimensions. Miners wore boots substantially longer than their feet, possibly due to inadequate width.

Footprint analysis and prevalence of flatfoot: a study among the children of South 24 Parganas, West Bengal, India

The present study envisages the morphological differences in anthropometric measurements on footprints among the preschool children and analyzes its manifestation in the different weight category. This study also focuses on the diagnosis of flatfoot among the studied population. Data has been collected from 160 participants (80 boys and 80 girls) from Bengali Hindu caste population aged 3 to 6 years. Anthropometric measurements included height, weight and body mass index. Other measurements on foot morphology included foot length, foot breadth diagonal, foot breadth horizontal, ball of the foot length, outside ball of the boot length, heel breadth, and toe lengths T1, T2, T3.T4, T5. Staheli’s Plantar Arch Index, Chippaux-Smirak Index and foot angle were calculated. Various statistical tests like t-test, Pearson’s correlation and ANOVA were performed. Among all the variables, foot breadth horizontal showed statistically significant difference between boys and girls (p<0.05). All the footprint dimensions showed a significant (p<0.05) positive correlation with height and weight in both the boys and the girls. However, the Staheli’s Plantar Arch Index showed a significant (p<0.05) negative correlation with height and weight and Chippaux-Smirak Index showed a significant (p<0.05) negative correlation with height only among both the boys and the girls. Significant differences (ANOVA) were found between the foot morphology of children in three different weight categories (underweight, healthy and overweight) except the foot angle, and both indices. The present study evinces that weight affects the foot structure of the children. The prevalence of flatfoot was found to be 57.5% among the children with no significant difference (p<0.05) between the boys and the girls. The results thus provide a podium for intricate studies in the future. Timely prognosis of flatfoot in children can instigate early rectification of flat-footedness.

A reliable measure of footwear upper comfort enabled by an innovative sock equipped with textile pressure sensors

Footwear comfort is essential and pressure distribution on the foot was shown as a relevant objective measurement to assess it. However, asperities on the foot sides, especially the metatarsals and the instep, make its evaluation difficult with available equipment. Thus, a sock equipped with textile pressure sensors was designed. Results from the mechanical tests showed a high linearity of the sensor response under incremental loadings and allowed to determine the regression equation to convert voltage values into pressure measurements. The sensor response was also highly repeatable and the creep under constant loading was low. Pressure measurements on human feet associated with a perception questionnaire exhibited that significant relationships existed between pressure and comfort perceived on the first, the third and the fifth metatarsals and top of the instep. Practitioner Summary: A sock equipped with textile sensors was validated for measuring the pressure on the foot top, medial and lateral sides to evaluate footwear comfort. This device may be relevant to help individuals with low sensitivity, such as children, elderly or neuropathic, to choose the shoes that fit the best.

Soccer players' fitting perception of different upper boot materials

The present study assessed the influence of upper boot materials on fitting perception. Twenty players tested three soccer boots only differing in the upper boot material (natural calf leather, natural kangaroo leather and synthetic leather). Players reported fitting perception and preference on specific foot areas using a perceived fitting scale. Ratings were averaged for every foot area. Repeated measures ANOVA was used to analyze the differences between boots. The kangaroo leather boots were perceived tighter and closer to the preferred fitting in general fitting, metatarsals area and instep area. The synthetic leather boots were perceived as the loosest and as the most distant boot from the preferred fitting in medial front area and instep area. In conclusion, the type of upper boot material influences the fitting perception of soccer players. The kangaroo leather was the material whose fitting was perceived closest to the players fitting preference.

Evolution of perceived footwear comfort over a prolonged running session

BACKGROUND

The purpose of this study was to investigate the subjective perception of overall footwear comfort over a prolonged running session.

METHODS

Ten runners performed two similar sessions consisting of a 13-km trail run (5 laps of 2.6 km) as fast as possible. The overall footwear comfort was evaluated before running and at the end of each lap with a 150-mm visual analogic scale, as well as speed, heart rate and rate of perceived exertion.

RESULTS

The results showed that both overall footwear comfort and speed decreased consistently during the run session, and significantly after 44 min of running (i.e. the 3rd lap). It could be hypothesized that the deterioration of overall footwear comfort was explained by mechanical and energetical parameter changes with time and/or fatigue occurring at the whole body, foot and footwear levels.

CONCLUSION

These results justify the use of a prolonged running test for running footwear comfort evaluation.

Subjective evaluation of running footwear depends on country and assessment method: a bi-national study

This study examined (1) the perception of running shoes between China (Beijing) and Singapore and (2) whether running shoe preference depended on assessment methods. One hundred (n = 50 each country) Chinese males subjectively evaluated four shoe models during running by using two assessment procedures. Procedure 1 used a visual analogue scale (VAS) to assess five perception variables. Procedure 2 was a 'head-to-head' comparison of two shoes simultaneously (e.g. left foot: A and right foot: B) to decide which model was preferred. VAS scores were consistently higher in Beijing participants (p < .001), indicating a higher degree of liking. Singapore participants used the lower end but a wider range of the 15 cm scale for shoe discrimination. Moderate agreement was seen between the VAS and 'head-to-head' procedures, with only 14 out of 100 participants matched all 6 pairwise comparisons (median = 4 matches). Footwear companies and researchers should be aware that subjective shoe preference may vary with assessment methods. Practitioner Summary: Footwear preference depends on country and assessment methods. Running shoe perception differed between Beijing and Singapore Chinese, suggesting that footwear recommendation should be country-specific. Individuals' shoe preference measured by visual analogue scale when wearing complete pairs may not reflect that when directly comparing different models in left and right feet.

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.

Comparing 3D foot scanning with conventional measurement methods

BACKGROUND

Foot dimension information on different user groups is important for footwear design and clinical applications. Foot dimension data collected using different measurement methods presents accuracy problems. This study compared the precision and accuracy of the 3D foot scanning method with conventional foot dimension measurement methods including the digital caliper, ink footprint and digital footprint.

METHODS

Six commonly used foot dimensions, i.e. foot length, ball of foot length, outside ball of foot length, foot breadth diagonal, foot breadth horizontal and heel breadth were measured from 130 males and females using four foot measurement methods. Two-way ANOVA was performed to evaluate the sex and method effect on the measured foot dimensions. In addition, the mean absolute difference values and intra-class correlation coefficients (ICCs) were used for precision and accuracy evaluation. The results were also compared with the ISO 20685 criteria.

RESULTS

The participant's sex and the measurement method were found (p < 0.05) to exert significant effects on the measured six foot dimensions. The precision of the 3D scanning measurement method with mean absolute difference values between 0.73 to 1.50 mm showed the best performance among the four measurement methods. The 3D scanning measurements showed better measurement accuracy performance than the other methods (mean absolute difference was 0.6 to 4.3 mm), except for measuring outside ball of foot length and foot breadth horizontal. The ICCs for all six foot dimension measurements among the four measurement methods were within the 0.61 to 0.98 range.

CONCLUSIONS

Overall, the 3D foot scanner is recommended for collecting foot anthropometric data because it has relatively higher precision, accuracy and robustness. This finding suggests that when comparing foot anthropometric data among different references, it is important to consider the differences caused by the different measurement methods.

The impact of different footwear characteristics, of a ballet flat pump, on centre of pressure progression and perceived comfort

BACKGROUND

Uncomfortable shoes have been attributed to poor fit and the cause of foot pathologies. Assessing and evaluating comfort and fit have proven challenging due to the subjective nature. The aim of this paper is to investigate the relationship between footwear characteristics and perceived comfort.

METHODS

Twenty-seven females assessed three different styles of ballet pump shoe for comfort using a comfort scale whilst walking along a 20 m walkway. The physical characteristics of the shoes and the progression of centre of pressure during walking were assessed.

RESULTS

There were significant physical differences between each style, square shoe being the shortest, widest and stiffest and round shoe having the least volume at the toe box. Centre of pressure progression angle was centralised to the longitudinal axis of the foot when wearing each of the three shoes compared to barefoot. Length, width and cantilever bending stiffness had no impact on perceived comfort.

CONCLUSION

Wearing snug fitting flexible soled round ballet flat pump is perceived to be the most comfortable of the shoe shapes tested producing a faster more efficient gait. Further investigations are required to assess impact/fit and upper material on perceived comfort to aid consumers with painful feet in purchasing shoes.

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.

Evaluation of the accuracy of shoe fitting in older people using three-dimensional foot scanning

Background

Ill-fitting footwear is a common problem in older people. The objective of this study was to determine the accuracy of shoe fitting in older people by comparing the dimensions of allocated shoes to foot dimensions obtained with a three-dimensional (3D) scanner.

Methods

The shoe sizes of 56 older people were determined with the Brannock device^®, and weightbearing foot scans were obtained with the FotoScan 3D scanner (Precision 3D Ltd, Weston-super-mare, UK). Participants were provided with a pair of shoes (Dr Comfort^®, Vista, CA, USA), available in three width fittings (medium, wide and extra wide). The dimensions (length, ball width and ball girth) of the allocated shoes were documented according to the last measurements provided by the manufacturer. Mean differences between last dimensions and foot dimensions obtained with the 3D scanner were calculated to provide an indication of shoe fitting accuracy. Participants were also asked to report their perception of shoe fit and comfort, using 100 mm visual analogue scales (VAS).

Results

Shoe size ranged from US size 7 to 14 for men and 5.5 to 11 for women. The allocated shoes were significantly longer than the foot (mean 23.6 mm, 95% confidence interval [CI] 22.1 to 25.2; t₅₅ = 30.3, p < 0.001), however there were no significant differences in relation to ball width (mean 1.4 mm, 95% CI −0.1 to 2.9 mm; t₅₅ = 1.9, p = 0.066) or ball girth (mean −0.7 mm, 95% CI −6.1 to 4.8 mm; t₅₅ = −0.2, p = 0.810). Participants reported favourable perceptions of shoe fit (mean VAS = 90.7 mm, 95% CI 88.4 to 93.1 mm) and comfort (mean VAS = 88.4 mm, 95% CI 85.0 to 91.8 mm).

Conclusion

Shoe size selection using the Brannock device® resulted in the allocation of shoes with last dimensions that were well matched to the dimensions of the foot. Participants also considered the shoes to be well fitted and comfortable. Older people with disabling foot pain can therefore be dispensed with appropriately-fitted shoes using this technique, provided that the style and materials used are suitable and extra width fittings are available.

Reliability and validity of the INFOOT three-dimensional foot digitizer for patients with rheumatoid arthritis

BACKGROUND

Abnormal foot posture and deformities are identified as important features in rheumatoid arthritis. There is still no consensus regarding the optimum technique(s) for quantifying these features; hence, a foot digitizer might be used as an objective measurement tool. We sought to assess the validity and reliability of the INFOOT digitizer.

METHODS

To investigate the validity of the INFOOT digitizer compared with clinical measurements, we calculated Pearson correlation coefficients. To investigate the reliability of the INFOOT digitizer, we calculated intraclass correlation coefficients, SEMs, smallest detectable differences, and smallest detectable difference percentages.

RESULTS

Most of the 38 parameters showed good intraclass correlation coefficients, with values greater than 0.9 for 30 parameters and greater than 0.8 for seven parameters. The left heel bone angle expressed a moderate correlation, with a value of 0.609. The SEM values varied between 0.31 and 3.51 mm for the length and width measures, between 0.74 and 5.58 mm for the height data, between 0.75 and 5.9 mm for the circumferences, and between 0.78° and 2.98° for the angles. The smallest detectable difference values ranged from 0.86 to 16.36 mm for length, width, height, and circumference measures and from 2.17° to 8.26° for the angle measures. For the validity of the INFOOT three-dimensional foot digitizer, Pearson correlation coefficients varied between 0.750 and 0.997.

CONCLUSIONS

In this rheumatoid arthritis population, good validity was demonstrated compared with clinical measurements, and most of the obtained parameters proved to be reliable.

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

One important extrinsic factor that causes foot deformity and pain in women is footwear. Women's sports shoes are designed as smaller versions of men's shoes. Based on this, the current study aims to identify foot shape in 1,236 Chinese young adult men and 1,085 Chinese young adult women. Three-dimensional foot shape data were collected through video filming. Nineteen foot shape variables were measured, including girth (4 variables), length (4 variables), width (3 variables), height (7 variables), and angle (1 variable). A comparison of foot measures within the range of the common foot length (FL) categories indicates that women showed significantly smaller values of foot measures in width, height, and girth than men. Three foot types were classified, and distributions of different foot shapes within the same FL were found between women and men. Foot width, medial ball length, ball angle, and instep height showed significant differences among foot types in the same FL for both genders. There were differences in the foot shape between Chinese young women and men, which should be considered in the design of Chinese young adults' sports shoes.

The use of 3D surface scanning for the measurement and assessment of the human foot

BACKGROUND

A number of surface scanning systems with the ability to quickly and easily obtain 3D digital representations of the foot are now commercially available. This review aims to present a summary of the reported use of these technologies in footwear development, the design of customised orthotics, and investigations for other ergonomic purposes related to the foot.

METHODS

The PubMed and ScienceDirect databases were searched. Reference lists and experts in the field were also consulted to identify additional articles. Studies in English which had 3D surface scanning of the foot as an integral element of their protocol were included in the review.

RESULTS

Thirty-eight articles meeting the search criteria were included. Advantages and disadvantages of using 3D surface scanning systems are highlighted. A meta-analysis of studies using scanners to investigate the changes in foot dimensions during varying levels of weight bearing was carried out.

CONCLUSIONS

Modern 3D surface scanning systems can obtain accurate and repeatable digital representations of the foot shape and have been successfully used in medical, ergonomic and footwear development applications. The increasing affordability of these systems presents opportunities for researchers investigating the foot and for manufacturers of foot related apparel and devices, particularly those interested in producing items that are customised to the individual. Suggestions are made for future areas of research and for the standardization of the protocols used to produce foot scans.

A new approach to children's footwear based on foot type classification

Current shoe designs do not allow for the comprehensive 3-D foot shape, which means they are unable to reproduce the wide variability in foot morphology. Therefore, the purpose of this study was to capture these variations of children's feet by classifying them into groups (types) and thereby provide a basis for their implementation in the design of children's shoes. The feet of 2867 German children were measured using a 3-D foot scanner. Cluster analysis was then applied to classify the feet into three different foot types. The characteristics of these foot types differ regarding their volume and forefoot shape both within and between shoe sizes. This new approach is in clear contrast to previous systems, since it captures the variability of foot morphology in a more comprehensive way by using a foot typing system and therefore paves the way for the unimpaired development of children's feet. Previous shoe systems do not allow for the wide variations in foot morphology. A new approach was developed regarding different morphological foot types based on 3-D measurements relevant in shoe construction. This can be directly applied to create specific designs for children's shoes.

Footbed shapes for enhanced footwear comfort

A shoe wearer's comfort is related to the shape of the footbed of a shoe. Even though the footbed shape is important in footwear design, there exists no methodology to evaluate the existing guidelines used in last making. Thirty-two females participated in an experiment where heel seat length, heel seat inclination and heel height were investigated using the profile assessment device. The dependent variables were plantar pressure and perceived feeling of each participant. The results show that perceived feel is best for wedge angles of 4 degrees and 5 degrees at a heel height of 25 mm, 10 degrees and 11 degrees at a heel height of 50 mm and 16 degrees and 18 degrees at a heel height of 75 mm. A regression model was derived and this explained approximately 80% of the variation of perceived feeling with the contact area, peak plantar pressure and percentage of force acting on the forefoot region. Both heel wedge angle and heel seat length play an important role in the perceived feel of high-heeled shoes. This study, in relation to the load-bearing heel part of a shoe, highlights the importance of good footbed design. The findings can be used to design footwear with enhanced comfort.

Effects of surface characteristics on the plantar shape of feet and subjects' perceived sensations

Orthotics and other types of shoe inserts are primarily designed to reduce injury and improve comfort. The interaction between the plantar surface of the foot and the load-bearing surface contributes to foot and surface deformations and hence to perceived comfort, discomfort or pain. The plantar shapes of 16 participants' feet were captured when standing on three support surfaces that had different cushioning properties in the mid-foot region. Foot shape deformations were quantified using 3D laser scans. A questionnaire was used to evaluate the participant's perceptions of perceived shape and perceived feeling. The results showed that the structure in the mid-foot could change shape, independent of the rear-foot and forefoot regions. Participants were capable of identifying the shape changes with distinct preferences towards certain shapes. The cushioning properties of the mid-foot materials also have a direct influence on perceived feelings. This research has strong implications for the design and material selection of orthotics, insoles and footwear.

Multi-resolution shape description and clustering of three-dimensional head data

The purpose of this study was to develop a 3-D anthropometric sizing method based on a clustering algorithm combined with a multi-resolution description and demonstrate the method with 3-D head data. Wavelet decomposition was adopted to provide flexible descriptions of 3-D shapes on different resolution levels. A block-division technique was then proposed to divide each decomposed 3-D surface into a predefined number of blocks. Afterwards, by using the block-distance metric, each decomposed surface was converted into a block-distance vector. Not only the size information but also the geometric information of the 3-D surfaces are contained in the vector. Finally, k-means clustering was performed on the vectors to segment the sample population into several groups. A total of 378 3-D upper head and face samples were analysed to illustrate the applicability of the method. Clustering was validated by using two measures, size-weighted variances and Clustering Validity Index. K-means clusterings of different variables were compared, including head length and head breadth, the top five principal components from principal component analysis (PCA) on the proposed block distance-based vectors and the block distance-based vectors directly. No obvious difference was found between clustering on the vectors with and without PCA. Lower values of the two measures when clustering on the block distance-based vectors indicated that the proposed block distance-based descriptor is superior to the traditional sizing dimensions of head length and head breadth. Unlike the traditional sizing methods based on key dimensions or derived variables, the method proposed in this study is based on the 3-D shape of the body surface. The proposed block-distance vector reflects not only the overall size but also the local spatial geometric features of a 3-D surface. The new method can be expected to improve the ergonomic design of those products requiring close fitting, such as face shields, goggles and helmets.

Sex-related differences in foot shape

The purpose of the study was to investigate sex-related differences in foot morphology. In total, 847 subjects were scanned using a 3-D-footscanner. Three different analysis methods were used: (1) comparisons were made for absolute foot measures within 250-270 mm foot length (FL); (2) and for averaged measures (% FL) across all sizes; (3) the feet were then classified using a cluster analysis. Within 250-270 mm FL, male feet were wider and higher (mean differences (MD) 1.3-5.9 mm). No relevant sex-related differences could be found in the comparison of averaged measures (MD 0.3-0.6% FL). Foot types were categorised into voluminous, flat-pointed and slender. Shorter feet were more often voluminous, longer feet were more likely to be narrow and flat. However, the definition of 'short' and 'long' was sex-related; thus, allometry of foot measures was different. For shoe design, measures should be derived for each size and sex separately. Different foot types should be considered to account for the variety in foot shape. Improper footwear can cause foot pain and deformity. Therefore, knowledge of sex-related differences in foot measures is important to assist proper shoe fit in both men and women. The present study supplements the field of knowledge within this context with recommendations for the manufacturing of shoes.

Modelling foot height and foot shape-related dimensions

The application of foot anthropometry to design good-fitting footwear has been difficult due to the lack of generalised models. This study seeks to model foot dimensions so that the characteristic shapes of feet, especially in the midfoot region, can be understood. Fifty Hong Kong Chinese adults (26 males and 24 females) participated in this study. Their foot lengths, foot widths, ball girths and foot heights were measured and then evaluated using mathematical models. The results showed that there were no significant allometry (p > 0.05) effects of foot length on ball girth and foot width. Foot height showed no direct relationship with foot length. However, a normalisation with respect to foot length and foot height resulted in a significant relationship for both males and females with R(2) greater than 0.97. Due to the lack of a direct relationship between foot height and foot length, the current practice of grading shoes with a constant increase in height or proportionate scaling in response to foot length is less than ideal. The results when validated with other populations can be a significant way forward in the design of footwear that has an improved fit in the height dimension.

A qualitative study on the comfort and fit of ladies' dress shoes

The perceived differences between comfortable and uncomfortable shoes and the fit preferences in the different regions of ladies' shoes were explored. Twenty Hong Kong Chinese females participated in the study. Each participant wore and rated the different aspects of their own comfortable and uncomfortable shoes. The Wilcoxon signed rank tests showed significant differences in ten perceived characteristics between the comfortable and uncomfortable shoes. Among the ten were tactile, auditory and olfactory sensations. The ten items reliably (Cronbach alpha>0.9) distinguished between comfortable and uncomfortable shoes. There were no significant differences between comfortable and uncomfortable shoes for aesthetic-related characteristics. Further analysis on the fit ratings showed a significant impact on the fit preferences in the Toe region (p<0.0001), Metatarsophalangeal (MPJ) region (p<0.0001), Arch region (p=0.002) and Ingress/egress opening (p<0.001). Knowing the preferred type of fit can help establish a specification for comfortable shoes and also brings out the criteria that a comfortable shoe does not necessarily have the same perceived fit in every region of a shoe.