Footwear Design Research Articles

Identification of subject-specific responses to footwear during running

Placing a stronger focus on subject-specific responses to footwear may lead to a better functional understanding of footwear’s effect on running and its influence on comfort perception, performance, and pathogenesis of injuries. We investigated subject-specific responses to different footwear conditions within ground reaction force (GRF) data during running using a machine learning-based approach. We conducted our investigation in three steps, guided by the following hypotheses: (I) For each subject x footwear combination, unique GRF patterns can be identified. (II) For each subject, unique GRF characteristics can be identified across footwear conditions. (III) For each footwear condition, unique GRF characteristics can be identified across subjects. Thirty male subjects ran ten times at their preferred (self-selected) speed on a level and approximately 15 m long runway in four footwear conditions (barefoot and three standardised running shoes). We recorded three-dimensional GRFs for one right-foot stance phase per running trial and classified the GRFs using support vector machines. The highest median prediction accuracy of 96.2% was found for the subject x footwear classification (hypothesis I). Across footwear conditions, subjects could be discriminated with a median prediction accuracy of 80.0%. Across subjects, footwear conditions could be discriminated with a median prediction accuracy of 87.8%. Our results suggest that, during running, responses to footwear are unique to each subject and footwear design. As a result, considering subject-specific responses can contribute to a more differentiated functional understanding of footwear effects. Incorporating holistic analyses of biomechanical data is auspicious for the evaluation of (subject-specific) footwear effects, as unique interactions between subjects and footwear manifest in versatile ways. The applied machine learning methods have demonstrated their great potential to fathom subject-specific responses when evaluating and recommending footwear.

Effect of muscle fatigue on metabolic cost in running and implications for footwear design

Effect of muscle fatigue on metabolic cost in running and implications for footwear design

Biomechanical modeling of footwear-fluid-floor interaction during slips

Slips and falls are among the major concerns for public safety. Slipping risks can be reduced by ensuring adequate traction at the shoe-floor interface. The outsole design of footwear is a critical factor to maintain sufficient shoe-floor traction in the presence of slippery contaminants such as water or oil. While the role of floorings and contaminants on footwear traction has been studied widely, limited works have investigated the role of footwear outsole geometry and tread patterns on shoe-floor traction. In this work, eight footwear outsole designs and their traction performance were tested on a common flooring with water contamination, through the development of a novel fluid–structure interaction based computational framework. Induced fluid pressure, mass flow rates, and contact areas were quantified across the outsole patterns, and their effect on footwear friction was investigated. The study results were validated using mechanical slip testing experiments. The results indicated that the outsoles which had horizontal treads or untreaded heel regions can lead to drastic reduction of footwear friction. Also, contact area alone was quantified to be a poor choice in estimating the traction performance of footwear on water contaminated floorings. Such novel study results have not been reported to date, and are anticipated to provide important guidelines to footwear manufacturers to evaluate and optimize footwear tread parameters which would help in reducing the risk of slips.

Statistical analysis on multi-factors of dynamic plantar pressure to normal subjects

Plantar pressure analysis has been found effective in many fields, such as rehabilitation evaluation, footwear design, nervous system disease analysis, etc. Plantar pressure features may be affected by many factors, such as age, gender, weight, etc., which cannot be ignored in related research and applications. Our research focuses on normal groups, mainly analyzes the differences between different age and gender groups, and considers the influence of height, weight, shoe size, and body mass index (BMI). Measured by a dynamic plantar pressure system, the plantar pressure data of the subjects in walking and standing states are analyzed. Through analysis by statistics and regression methods, we draw the following main conclusions: (1) there are obvious differences between young and old groups in static features, reflecting the impact of age on human balance; (2) the difference between men and women is more in the pressure distribution of the plantar region, especially in the metatarsal region, reflecting the difference in the physiological structure caused by gender; (3) it is also found that height, weight, shoe size and BMI have certain effects.

Effect of pregnancy on female gait characteristics: a pilot study based on portable gait analyzer and induced acceleration analysis.

Introduction: The changes in physical shape and center of mass during pregnancy may increase the risk of falls. However, there were few studies on the effects of maternal muscles on gait characteristics and no studies have attempted to investigate changes in induced acceleration during pregnancy. Further research in this area may help to reveal the causes of gait changes in women during pregnancy and provide ideas for the design of footwear and clothing for pregnant women. The purpose of this study is to compare gait characteristics and induced accelerations between non-pregnant and pregnant women using OpenSim musculoskeletal modeling techniques, and to analyze their impact on pregnancy gait. Methods: Forty healthy participants participated in this study, including 20 healthy non-pregnant and 20 pregnant women (32.25 ± 5.36weeks). The portable gait analyzer was used to collect participants' conventional gait parameters. The adjusted OpenSim personalized musculoskeletal model analyzed the participants' kinematics, kinetics, and induced acceleration. Independent sample T-test and one-dimensional parameter statistical mapping analysis were used to compare the differences in gait characteristics between pregnant and non-pregnant women. Results: Compared to the control group, pregnancy had a 0.34m reduction in mean walking speed (p < 0.01), a decrease in mean stride length of 0.19m (p < 0.01), a decrease in mean stride frequency of 19.06 step/min (p < 0.01), a decrease in mean thigh acceleration of 0.14m/s2 (p < 0.01), a decrease in mean swing work of 0.23g (p < 0.01), and a decrease in mean leg falling strength of 0.84g (p < 0.01). Induced acceleration analysis showed that pregnancy muscle-induced acceleration decreased in late pregnancy (p < 0.01), and the contribution of the gastrocnemius muscle to the hip and joint increased (p < 0.01). Discussion: Compared with non-pregnant women, the gait characteristics, movement amplitude, and joint moment of pregnant women changed significantly. This study observed for the first time that the pregnant women relied more on gluteus than quadriceps to extend their knee joints during walking compared with the control group. This change may be due to an adaptive change in body shape and mass during pregnancy.

Empirical study on design and development of hand-crafted footwear

With its enormous potential in terms of employment, growth, and exports, the footwear industry is an important player in the Indian context, and can contribute to the nation's economic development. It is worth noting here that leather footwear in Kolhapuri style has a distinguished history spanning hundreds of years. This craft style is a labor-intensive production process in which the primitive nature of the tools and equipment are used. In the present context, this craft style is about to go extinct because of artisans' declining interest. The present study reports an attempt to improve the manufacturing procedure and productivity without changing the fundamental nature of the craft (its actual essence). The study reports on the local craft cluster's efforts to rethink the craft style in terms of technological interventions, skill development, product diversification, commercial opportunities, etc. Further, the study reports the necessity of conducting social workshops on design innovations. The study advocates the revitalization of Kolhapur's identity and the need for acceleration of this dying craft.

Physiological and Biomechanical Monitoring in American Football Players: A Scoping Review.

American football is the sport with the highest rates of concussion injuries. Biomedical engineering applications may support athletes in monitoring their injuries, evaluating the effectiveness of their equipment, and leading industrial research in this sport. This literature review aims to report on the applications of biomedical engineering research in American football, highlighting the main trends and gaps. The review followed the PRISMA guidelines and gathered a total of 1629 records from PubMed (n = 368), Web of Science (n = 665), and Scopus (n = 596). The records were analyzed, tabulated, and clustered in topics. In total, 112 studies were selected and divided by topic in the biomechanics of concussion (n = 55), biomechanics of footwear (n = 6), biomechanics of sport-related movements (n = 6), the aerodynamics of football and catch (n = 3), injury prediction (n = 8), heat monitoring of physiological parameters (n = 8), and monitoring of the training load (n = 25). The safety of players has fueled most of the research that has led to innovations in helmet and footwear design, as well as improvements in the understanding and prevention of injuries and heat monitoring. The other important motivator for research is the improvement of performance, which has led to the monitoring of training loads and catches, and studies on the aerodynamics of football. The main gaps found in the literature were regarding the monitoring of internal loads and the innovation of shoulder pads.

Influence of Vertically Treaded Outsoles on Interfacial Fluid Pressure, Mass Flow Rate, and Shoe–Floor Traction during Slips

Accidental injuries due to slips and falls are considered serious threats to public safety. Sufficient friction at the footwear and flooring interface is essential to reduce slip-related risks. The presence of slippery fluidic contaminants, such as water, further reduces friction and increases the risks of slip-related accidents drastically. While the effect of floorings and contaminants on footwear traction has been measured extensively across a variety of footwear designs, only a few studies have explored the science of the outsole design and its role in providing sufficient traction. In this work, the tread design of a commonly encountered outsole pattern, i.e., with vertically oriented tread channels, was parametrically altered across its width and gap. Based on the impressions of an original footwear design, nine outsoles were fabricated. The induced fluid pressures, mass flow rates, and traction were quantified by using a computational fluid dynamics (CFD) framework and through slip testing experiments. Outsoles that had wide treads with small gaps decreased the overall slipping risk on dry floorings. As compared to the tread area, tread gaps were found to be a dominating parameter in providing adequate shoe–floor traction in wet slipping conditions. The methods, including the outcomes presented in this work, are anticipated to advance the understanding of the science behind footwear friction and help footwear manufacturers optimize outsole designs to reduce slip and fall risks.

It is about inclusion! Mining online reviews to understand the needs of adaptive clothing customers

AbstractThe adaptive clothing market, which focuses on the inclusive design of clothing and footwear for people with varying degrees of disability, has grown substantially in recent years. However, few scholars have sought to understand the perspectives of online adaptive clothing consumers. This study employed topic modelling, sentiment analysis and collocation analysis to discover common themes and insights emerging from online customer reviews, scraped from a third‐party review platform and three retailing web sites. We utilized customer value and functional, expressive and aesthetic theories to group the results from topic modelling into key themes. Clothing function is the most frequently discussed theme in online customer reviews, followed by customer service and clothing aesthetics. Collocation analysis revealed the cause underlying each theme vis‐à‐vis customer satisfaction (e.g., fit and material quality) and dissatisfaction (e.g., sewing defects and lost shipment). The findings contribute to understanding the clothing needs and wants of people living with disabilities. It also provides practical guidelines on product offerings and online service optimization for adaptive clothing retailers.

Design optimisation of TPU modular footwear for sustainable fashion: a South African Fashion Week case study, 2023

The fashion industry is continuously evolving, and Thermoplastic Polyurethane (TPU) produced modular footwear is emerging as a trend for sustainability. This study aims to optimise the design of TPU modular fashion footwear for the South African fashion sector. The practice-based case study investigated the factors that influence the design and manufacturing of modular footwear using TPU, with a focus on enhancing sustainability. A design framework was developed using CAD software and evaluated the effectiveness of the optimised design in enhancing sustainability through a case study conducted at the SA Fashion Week in 2023. A combination of quantitative and qualitative research methods was employed to collect and analyse data, contributing to the development of sustainable and fashionable modular footwear for the fashion industry. It further provides insights into the challenges associated with the design and manufacturing of TPU modular fashion footwear.

Kinetic coupling in distal foot joints during walking

BackgroundKinematic coupling between the first metatarsophalangeal (MTP) and midtarsal joints is evident during gait and other movement tasks, however kinetic foot coupling during walking has not been examined. Furthermore, contributing factors to foot coupling are still unclear. Therefore, the purpose of this study was to investigate kinematic and kinetic coupling within the foot by restricting MTP motion during overground walking. We hypothesized that when the MTP joint was prevented from fully extending, the midtarsal joint would achieve less peak motion and generate less positive work compared to walking with normal MTP motion.MethodsTwenty-six individuals participated in this randomized cross-over study. Using motion capture to track motion, participants walked at 1.3 m/s while wearing a brace that restricted MTP motion in a neutral (BR_NT) or extended (BR_EX) position. Additionally, participants walked while wearing the brace in a freely moveable setting (BR_UN) and with no brace (CON). A pressure/shear sensing device was used to capture forces under each foot segment. During stance, peak joint motion and work were calculated for the MTP and midtarsal joints using inverse dynamics. A series of ANOVAs and Holm post hoc tests were performed for all metrics (alpha = 0.05).ResultsThe brace successfully decreased peak MTP motion by 19% compared to BR_UN and CON. This was coupled with 9.8% less midtarsal motion. Kinetically, the work absorbed by the MTP joint (26–51%) and generated by the midtarsal joint (30–38%) were both less in BR_EX and BR_NT compared to BR_UN.ConclusionImplications and sources of coupling between the MTP and midtarsal joints are discussed within the context of center of pressure shifts and changes to segmental foot forces. Our results suggest that interventions aimed at modulating MTP negative work (such as footwear or assistive device design) should not ignore the midtarsal joint.

Теплозащитные свойства специальной защитной обуви пожарного-спасателя

PURPOSE. The relevance of providing firefighter-rescuer’s feet with reliable protection against dangerous factors in emergency situations is beyond any doubt. The purpose of the given work was to give theoretical and experimental justification to heat-protective properties of the materials used for producing special protective boots for а firefighter-rescuer, which allows evaluating the material thermal behavior under various external impacts, thereby further optimizing the boots design by selecting different sets of materials. METHODS. The general methodology of the work envisaged a combination of theoretical and experimental studies of heat protective characteristics of firefighter-rescuer special protective footwear along with mathematical and statistical processing of experimental data. FINDINGS. Based on mathematical modeling, a method for calculating heat and moisture transfer in special protective footwear for firefighter-rescuers has been obtained, which allows optimizing footwear design by selecting different sets of materials or assessing thermal behavior under various external impacts. The time of reaching a critical temperature of 50 °C in a boot inner area, at which the layer of a human skin tissue begins to get destroyed, under intense thermal influence on the top layer of shoes of 5 kW/m2 (tкр ≤ 10 min) and the thermal conductivity coefficient value of the material set for producing special protective boots (λ = 0.03–0.06 W/(m⋅K)) have been experimentally established. RESEARCH APPLICATION FIELD. The obtained results can be used for implementation and effective use of special firefighter-rescuer protective boots in emergency elimination practice. CONCLUSIONS. The obtained research results will allow justifying theoretically and experimentally material choice for producing special protective footwear with the improved consumer properties for firefighter-rescuers.

Occupational Footwear Design Influences Biomechanics and Physiology of Human Postural Control and Fall Risk

While design modifications present on work boots improve safety, they may not always provide optimal human performance during work tasks. Understanding the impact of these different design features on biomechanical and physiological postural control and locomotion variables can aid in better design modifications that can provide a safe and efficient human performance. This brief review focuses on a series of studies conducted by the current research team, that have tested three different work boots (SB: high-top steel-toed work boots; TB: high-top tactical work boots; SR: low-top slip-resistant work boots). The series of studies included testing of these work boots or combinations of them under acute and chronic simulated occupational workloads, assessing biomechanical variable such as postural stability, gait, slips, and muscle activity, as well as physiological variables such as heart rate, energy expenditure, oxygen consumption, and pain perception. The impact of each of the work boots and their design feature on postural control and locomotion are summarized from these studies’ previously published literature. Finally, work boot design suggestions for optimal human performance are provided for better work boot selection, modification, and design.

Footwear and insole design parameters to prevent occurrence and recurrence of neuropathic plantar forefoot ulcers in patients with diabetes: a series of N-of-1 trial study protocol

BackgroundFoot complications occur in conjunction with poorly controlled diabetes. Plantar forefoot ulceration contributes to partial amputation in unstable diabetics, and the risk increases with concomitant neuropathy. Reducing peak plantar forefoot pressure reduces ulcer occurrence and recurrence. Footwear and insoles are used to offload the neuropathic foot, but the success of offloading is dependent on patient adherence. This study aims to determine which design and modification features of footwear and insoles improve forefoot plantar pressure offloading and adherence in people with diabetes and neuropathy.MethodsThis study, involving a series of N-of-1 trials, included 21 participants who had a history of neuropathic plantar forefoot ulcers. Participants were recruited from two public hospitals and one private podiatry clinic in Sydney, New South Wales, Australia. This trial is non-randomised and unblinded. Participants will be recruited from three sites, including two high-risk foot services and a private podiatry clinic in Sydney, Australia. Mobilemat™ and F-Scan® plantar pressure mapping systems by TekScan® (Boston, USA) will be used to measure barefoot and in-shoe plantar pressures. Participants’ self-reports will be used to quantify the wearing period over a certain period of between 2 and 4 weeks during the trial. Participant preference toward footwear, insole design and quality-of-life-related information will be collected and analysed. The descriptive and inferential statistical analyses will be performed using IBM SPSS Statistics (version 27). And the software NVivo (version 12) will be utilised for the qualitative data analysis.DiscussionThis is the first trial assessing footwear and insole interventions in people with diabetes by using a series of N-of-1 trials. Reporting self-declared wearing periods and participants’ preferences on footwear style and aesthetics are the important approaches for this trial. Patient-centric device designs are the key to therapeutic outcomes, and this study is designed with that strategy in mind.Trial registrationAustralian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12620000699965p. Registered on June 23, 2020

OptiFit: Computer-Vision-Based Smartphone Application to Measure the Foot from Images and 3D Scans

The foot is a vital organ, as it stabilizes the impact forces between the human skeletal system and the ground. Hence, precise foot dimensions are essential not only for custom footwear design, but also for the clinical treatment of foot health. Most existing research on measuring foot dimensions depends on a heavy setup environment, which is costly and ineffective for daily use. In addition, there are several smartphone applications online, but they are not suitable for measuring the exact foot shape for custom footwear, both in clinical practice and public use. In this study, we designed and implemented computer-vision-based smartphone application OptiFit that provides the functionality to automatically measure the four essential dimensions (length, width, arch height, and instep girth) of a human foot from images and 3D scans. We present an instep girth measurement algorithm, and we used a pixel per metric algorithm for measurement; these algorithms were accordingly integrated with the application. Afterwards, we evaluated our application using 19 medical-grade silicon foot models (12 males and 7 females) from different age groups. Our experimental evaluation shows that OptiFit could measure the length, width, arch height, and instep girth with an accuracy of 95.23%, 96.54%, 89.14%, and 99.52%, respectively. A two-tailed paired t-test was conducted, and only the instep girth dimension showed a significant discrepancy between the manual measurement (MM) and the application-based measurement (AM). We developed a linear regression model to adjust the error. Further, we performed comparative analysis demonstrating that there were no significant errors between MM and AM, and the application offers satisfactory performance as a foot-measuring application. Unlike other applications, the iOS application we developed, OptiFit, fulfils the requirements to automatically measure the exact foot dimensions for individually fitted footwear. Therefore, the application can facilitate proper foot measurement and enhance awareness to prevent foot-related problems caused by inappropriate footwear.

Impact of advanced footwear technology on elite men’s in the evolution of road race performance

ABSTRACT Advanced footwear technology (AFT) changed footwear design concepts by using a curved carbon fibre plate in combination with new, more compliant and resilient foams. The aim of this study was (1) to examine the individual effects of AFT on the evolution of the main road events and (2) to re-assess the impact of AFT on the world’s top-100 performance in men’s 10k, half-marathon and marathon events. Data from the top-100 men’s 10k, half-marathon and marathon performances were collected between 2015 and 2019. The shoes used by the athletes were identified in 93.1% of the cases by publicly available photographs. Runners wearing AFT had an average performance of 1671 ± 22.28 s compared to 1685 ± 18.97 s of runners not using AFT in 10k (0.83%) (p < 0.001), 3589 ± 29.79 s compared to 3607 ± 30.49 s in half-marathon (0.50%) (p < 0.001) and 7563 ± 86.10 s compared to 7637 ± 72.51 s in the marathon (0.97%) (p < 0.001). Runners wearing AFTs were faster by ~1% in the main road events compared to non-users. Individual analysis showed that ~25% of the runners did not benefit from the use of this type of footwear. The results of this study suggest that AFT has a clear positive impact on running performance in main road events.

Better understanding the life of the user to improve the design of orthopaedic footwear

BACKGROUND: A relatively high number of users is dissatisfied with their orthopaedic device. The term ‘user practice’ was introduced to emphasise the idea that users of orthopaedic devices perform activities within an environment, which are characteristic for that environment. OBJECTIVE: To investigate to what extend orthopaedic shoe engineers map the specific environments in which users live and the activities they perform within these environments during the first intake for custom made orthopaedic footwear. METHODS: Orthopaedic shoe engineers were recruited from orthopaedic service providers across The Netherlands. The intake with a new client for orthopaedic footwear was recorded and analysed using four user environments: daily life at home, transport, work, and leisure. RESULTS: Our study showed that orthopaedic shoe engineers cover at best less than 50% of activities within the four user environments. Consequently, there is no guarantee that the resulting design of the orthopaedic footwear fits all of the activities and environments of the users. CONCLUSIONS: The principles of user practices, consisting of specific environments and activities of the user, are not yet adequately used in the field of orthopaedic shoe engineering. By not using them, too little understanding of the life of the user can result in dissatisfaction and non-usage of the orthopaedic device.

A study of consumer preferences in professional dance shoes

The article presents the results of a marketing research conducted to identify consumer preferences when choosing shoes for professional dancing. The study is part of an integrated approach to the study of the most important parameters in the design and improvement of special footwear for dancers. The survey involved artists of various dance groups, including ensembles with a worldwide reputation, such as the State Academic Choreographic Ensemble «Berezka» named after N.S. Nadezhdina, the Academic Song and Dance Ensemble of the National Guard of the Russian Federation, as well as students of specialized dance universities and schools. The respondents also included dancers who had taken part in our earlier anthropometric study. The selected method of collecting sociological information based on the use of Internet technology was carried out in the form of an interactive questionnaire located on an electronic resource. The method has a number of advantages, including the ability to fill in from a computer or mobile device online, unlimited in time, which is an important factor in obtaining full-fledged objective results among creative youth with a heavy workload in the educational and rehearsal process. According to the results of the study, the most important properties of shoes for consumers were identified, such as the materials from which various models of «jazz shoes» are made, the correspondence of the internal shape of the shoe to the individual foot, the areas of the shoe design where dancers experience discomfort during operation, as well as the most popular models of «jazz shoes». The data obtained through the survey opens up the prospect of improving the design of «jazz shoes».

Development and Validation of a Subject-Specific Coupled Model for Foot and Sports Shoe Complex: A Pilot Computational Study.

Nowadays, footwear serves an essential role in improving athletic performance and decreasing the risk of unexpected injuries in sports games. Finite element (FE) modeling is a powerful tool to reveal the biomechanical interactions between foot and footwear, and establishing a coupled foot-shoe model is the prerequisite. The purpose of this pilot study was to develop and validate a 3D FE coupled model of the foot and sports shoe complex during balanced standing. All major foot and shoe structures were constructed based on the participant’s medical CT images, and 3D gait analysis was conducted to define the loading and boundary conditions. Sensitivity analysis was applied to determine the optimum material property for shoe sole. Both the plantar and shoe sole areas were further divided into four regions for model validation, and the Bland–Altman method was used for consistency analysis between methods. The simulated peak plantar and sole pressure distribution showed good consistency with experimental pressure data, and the prediction errors were all less than 10% during balanced standing with only two exceptions (medial and lateral forefoot regions). Meanwhile, the Bland–Altman analysis demonstrated a good agreement between the two approaches. The sensitivity analysis suggested that shoe sole with Young’s modulus of 2.739 MPa presented the greatest consistency with the measured data in our scenario. The established model could be used for investing the complex biomechanical interactions between the foot and sports shoe and optimizing footwear design, after it has been fully validated in the subsequent works under different conditions.

Inverse Design of Mechanical Metamaterials with Target Nonlinear Response via a Neural Accelerated Evolution Strategy (Adv. Mater. 41/2022)

Mechanical Metamaterials In article number 2206238, Bolei Deng, Katia Bertoldi, and co-workers present a neural accelerated evolution strategy to inverse design mechanical metamaterials with targeted nonlinear responses. The proposed platform could support the design of innovative footwear.