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

Immediate effect of the use of toe separators on dynamic balance and ankle range of motion: a pilot study

BACKGROUND AND OBJECTIVES

Injuries involving ankle stability and range of motion are among the most frequent in athletes and in the general population. In response, this study aimed to assess the immediate effects of toe separators on dynamic stability and ankle range of motion in healthy young individuals.

METHODS

Among the 68 eligible participants, 50 healthy and active subjects completed all trials. The impact of the intervention was evaluated using the Weight Bearing Lunge Test and Y-Test. The control condition performed the tests without toe separators, while the experimental condition performed the tests with toe separators. All participants performed both conditions with a wash-out period of at least 7 days between trials.

RESULTS

Statistical analysis revealed no significant differences in dynamic balance (p > 0.05) and range of motion (p > 0.05) between the two conditions. Additionally, no asymmetries were detected between the lower limbs in both tests (p > 0.05).

CONCLUSIONS

The results of this pilot study indicate that using toe separators does not have an immediate effect on ankle range of motion and dynamic balance in young, healthy individuals. Future research should consider evaluating intervention programs of longer duration and exploring different populations.

Footwear comfort: a systematic search and narrative synthesis of the literature

OBJECTIVE

To provide a narrative synthesis of the research literature pertaining to footwear comfort, including definitions, measurement scales, footwear design features, and physiological and psychological factors.

METHODS

A systematic search was conducted which yielded 101 manuscripts. The most relevant manuscripts were selected based on the predetermined subheadings of the review (definitions, measurement scales, footwear design features, and physiological and psychological factors). A narrative synthesis of the findings of the included studies was undertaken.

RESULTS

The available evidence is highly fragmented and incorporates a wide range of study designs, participants, and assessment approaches, making it challenging to draw strong conclusions or implications for clinical practice. However, it can be broadly concluded that (i) simple visual analog scales may provide a reliable overall assessment of comfort, (ii) well-fitted, lightweight shoes with soft midsoles and curved rocker-soles are generally perceived to be most comfortable, and (iii) the influence of sole flexibility, shoe microclimate and insoles is less clear and likely to be more specific to the population, setting and task being performed.

CONCLUSION

Footwear comfort is a complex and multifaceted concept that is influenced not only by structural and functional aspects of shoe design, but also task requirements and anatomical and physiological differences between individuals. Further research is required to delineate the contribution of specific shoe features more clearly, and to better understand the interaction between footwear features and individual physiological attributes.

A Reconfigurable and Adjustable Compliance System for the Measurement of Interface Orthotic Properties

Custom foot orthoses (CFOs) have shown treatment effectiveness by providing improved pressure/load redistribution, skeletal support and comfort level. However, the current design methodologies of CFOs have some problems: (1) the plantar surface is captured without considering the soft tissue impedance, (2) the stiffness of the CFOs is limited to rigid, semi-rigid and soft, which ignores the potential effect of local variation of stiffness on the interface pressure/load distribution and subjective evaluations, and (3) the lack of a human-in-the-loop may lead to multiple design-to-deliver iterations. A new prescription methodology of CFOs is required to satisfy the pressure/load distribution, improve comfort level and decrease iterations.

METHOD

A measurement system which provides INterface with Tunable Ergonomic properties using a Reconfigurable Framework with Adjustable Compliant Elements (INTERFACE system) is developed to implement the Rapid Evaluate and Adjust Device (READ) methodology. The geometry and stiffness of the Medial Longitudinal Arch (MLA) support provided by the INTERFACE system can be adjusted via linear actuators and tunable stiffness mechanisms, based on objective interface pressure/load distribution and subjective feedback evaluations. Validation tests were conducted on 13 subjects to measure the plantar pressure/load distribution and record the subjective feedback in different combinations of geometry and stiffness.

RESULTS

The interface pressure/load distribution and subjective feedback of the support level indicate the efficacy of the adjustable geometry and stiffness. As the stiffness and geometrical height increased, the plantar loadings increased in the MLA region and decreased in the rear foot. Geometrical fitting can be achieved with the reconfigurable MLA support. The integration of locally adjustable stiffness makes it possible to fine tune the plantar pressure/load and provides the subjects with options of orthotic stiffness.

CONCLUSION

The proposed INTERFACE system can be applied to conduct the measurement of the desired orthotic properties which satisfy the interface pressure/load requirement and the subject's comfort.

Design of a Modular Plantar Orthosis System through the Application of TRIZ Methodology Tools

Innovations within the medical device sector are constantly and rapidly emerging due to increasing demand, especially for orthosis systems, which usually constitute built rigids with low comfort, due mainly to the standardized production process. This article reports the design process of a plantar orthosis system from the application of Theory of Inventive Problem Solving (TRIZ) tools, known as generic parameters, matrix of contradictions, and inventive principles. The final orthosis is integrated by four modules or components (1 central and 3 movables) and customers can buy only the required ones, reducing cost in unnecessary parts. The plantar orthosis was defined based on three engineering parameters that delimited the design work by developing a customizable system that is capable of performing simultaneous functions and whose manufacture could be standardized. We identified the existence of a technical contradiction between the engineering parameters, customization, and standardization, which was solved by the inventive principles of segmentation, inversion, transition to a new dimension, and porous materials. A modular design with four components was accomplished, molds are built for each component in a machining center and injected using granulated ethylene vinyl acetate copolymer. The positions of the movable components are configured through a bolt-hole assembly mechanism to the central component, which is a flat perforated plantar base. The novelty in the design here presented is elated to supports that constitute the orthosis, which are interchangeable and adjustable to the pathological and morphological needs of each patient.

A preliminary study to identify data needs for improving fit of hand and wrist orthosis using verbal protocol analysis

The delayed delivery, poor fitting and discomfort of customised orthoses are reported in rehabilitation clinics as resulting in more invasive interventions. The current practice of orthosis customisation relies heavily upon the experience and fabrication processes of therapists. In order to better understand the current practice, and thus identify data that is required for better comfort moving towards a data-driven customisation, this article describes a study generating working models of therapists. Customisations of hand and wrist orthoses for 18 patients were observed. Verbal protocol analysis was employed to extend the current understanding of fabrication processes. Working models of four therapists were established with quantitative evaluation on major phases, interactive activities and iterations of performing tasks during fabrication, revealing different working models between in- and out-patient departments (e.g. fabrication for in-patients was more complex and focussed on ergonomic fitting whereas fabrication for out-patients paid attention to durability) which were qualitatively explained. Practitioner summary: Fit and comfort are imperative for orthosis design and fabrication, however the current practice of customisation of an orthosis relies upon the experience of individual hand therapist. The article presents working models of hand therapists, and relevant data that would enable customisation of orthosis for better fit. Abbreviations: VPA: verbal protocol analysis; h&w: hand and wrist; LTT: low temperature thermoplastic; ANOVA: analysis of variance.

Insoles of uniform softer material reduced plantar pressure compared to dual-material insoles during regular and loaded gait

There is limited evidence on the efficacy of insole materials to reduce plantar pressure during regular walking and loaded walking. In-shoe plantar pressures and subjective footwear comfort were recorded in twenty healthy participants at a self-selected treadmill walking speed in six conditions: two commercial insoles or no insole, and with or without carrying a load in a backpack. A single-material insole, comprised of polyurethane, had reduced density and compressive stiffness compared to a dual-material insole with added viscoelastic material in rearfoot and forefoot regions. Load carriage increased peak pressure across the foot. Both insoles reduced plantar pressure in the rearfoot. Yet, the softer single-material insole also attenuated forefoot pressure and loaded walking did not appear to cause bottoming-out of the polyurethane. Plantar pressure changes did not affect perceived footwear comfort. The softer single-material insole was more effective in reducing plantar pressure, further research would confirm if this influences injury prevalence.

The Impact of a Foot-Toe Orthosis on Dynamic Balance: An Exploratory Randomized Control Trial

CONTEXT

The influence of custom and over-the-counter foot orthoses on dynamic balance has been investigated in the past. However, there has not been an exploration of the use of a foot-toe orthosis for improving balance. The ability of clinicians to influence balance could have important implications for injury prevention and rehabilitation.

OBJECTIVE

To determine the impact of a foot-toe orthosis on dynamic balance in healthy, young adults.

DESIGN

Randomized control trial.

SETTING

Athletic training laboratory.

PARTICIPANTS

In total, 64 healthy, recreationally active participants aged 18-29 years were randomly allocated to one of the following groups: the foot-toe orthosis and laboratory-issued shoe group, the laboratory-issued shoe only (SO) group, or the control group.

INTERVENTIONS

Subjects in the intervention group wore the foot-toe orthosis and laboratory-issued shoe with activities of daily living for 4 weeks. Subjects in the SO intervention group wore the laboratory-issued shoe with activities of daily living for 4 weeks. Participants in the control group did not receive any intervention.

MAIN OUTCOME MEASURES

The instrumented version of the Star Excursion Balance Test, known as the Lower Quarter Y-Balance Test, was used to quantify the dynamic balance at baseline and follow-up. Reaches were normalized for leg length.

RESULTS

There were statistically significant differences in postintervention scores on the Lower Quarter Y-Balance Test for both the dominant (P = .03, effect size = 0.84; 95% confidence interval, 0.25 to 1.43) and nondominant (P = .002, effect size = 0.74; 95% confidence interval, 0.15 to 1.32) legs when comparing dynamic balance scores of the foot-toe orthosis and laboratory-issued shoe group with the SO and control groups. No significant differences were observed when comparing dynamic balance between the SO and control groups.

CONCLUSIONS

A 4-week intervention with a foot-toe orthosis and laboratory-issued shoe resulted in improved dynamic balance in a healthy young adult population. These findings suggest a novel intervention for increasing balance.

The Effectiveness of Personalized Custom Insoles on Foot Loading Redistribution during Walking and Running

The objective of this study was to investigate the effectiveness of different hardness of personalized custom insoles on plantar pressure redistribution in healthy young males during walking and running. Six males participated in the walking and running test (age: 24±1.6 years, weight: 67.9±3.6 kg, height: 175.5±4.7 cm). All subjects were instructed to walk and run along a 10m pathway wearing two different hardness insoles (i.e., hard custom insoles (CHI) and soft custom insole (CSI)) and control insole (CI) at their preferred speed. Peak pressure, mean pressure, maximum force, pressure-time integral were collected to analyze using SPSS. The plantar pressure of forefoot and medial midfoot were significantly increased and of lateral forefoot and lateral midfoot were decreased by both kinds of custom insoles in running tests. While the CHI significantly increased plantar pressure of the medial forefoot compared with the CSI and CI both in walking and running tests. The custom insoles showed significantly higher plantar pressure on medial midfoot. But CSI seems better than CHI because of redistributing the plantar pressure by increasing the plantar pressure of whole forefoot. Moreover, CSI showed significantly lower plantar pressure than CI and CHI at lateral midfoot during running test. The CHI causes significant high pressure at medial forefoot (MF), which may raise the risk of forefoot pain.

Age-related changes in postural control for wearing shoes using different process of leg-raising processes in the sitting position: a pilot study

[Purpose] Wearing shoes can be difficult for people who experience movement difficulties. This study aimed to compare young adults and senior adults while wearing shoes in order to quantify kinematic, physiological, and ergonomic points of variance. [Participants and Methods] Nine young adults (mean age, 21 years) and nine senior adults (mean age, 70 years) were included in the study. We investigated four postural combination of using hand and crossing legs used while wearing shoes: 1) time required to wear shoes, 2) the center of pressure point, 3) muscle activation within the right sartorius, the left rectus femoris, the gluteus maximus, and the internal oblique, and 4) the perceived ease of task performance via a numerical rating scale. [Results] The activities of the internal oblique and the gluteus maximus were significantly higher in senior adults than in young adults. Wearing shoes without using hands was associated with the highest value for the ease of performance among the four patterns for both groups. [Conclusion] Our results suggested that the muscles analyzed in this study were important for safety and postural maintenance while performing activities of daily living tasks in leg-raising processes in the sitting position, with lower level of muscle activity.

Analysis of Insole Geometry and Deformity by Using a Three-Dimensional Image Processing Technique: A Preliminary Study

BACKGROUND

Accurate representation of the insole geometry is crucial for the development and performance evaluation of foot orthoses designed to redistribute plantar pressure, especially for diabetic patients.

METHODS

Considering the limitations in the type of equipment and space available in clinical practices, this study adopted a simple portable three-dimensional (3-D) desktop scanner to evaluate the 3-D geometry of an orthotic insole and the corresponding deformities after the insole has been worn. The shape of the insole structure along horizontal cross sections is defined with 3-D scanning and image processing. Accompanied by an in-shoe pressure measurement system, plantar pressure distribution in four foot regions (hallux, metatarsal heads, midfoot, and heel) is analyzed and evaluated for insole deformity.

RESULTS

Insole deformities are quantified across the four foot regions. The hallux region tends to show the greatest changes in shape geometry (17%-50%) compared with the other foot regions after 2 months of insole wear. As a result of insole deformities, plantar peak pressures change considerably (-4.3% to +69.5%) during the course of treatment.

CONCLUSIONS

Changes in shape geometry of the insoles could be objectively quantified with 3-D scanning techniques and image processing. This investigation finds that, in general, the design of orthotic insoles may not be adequate for diabetic individuals with similar foot problems. The drastic changes in the insole shape geometry and cross-sectional areas during orthotic treatment may reduce insole fit and conformity. An inadequate insole design may also affect plantar pressure reduction. The approach proposed herein, therefore, allows for objective quantification of insole shape geometry, which results in effective and optimal orthotic treatment.

Can an off-the-rack orthotic stiletto alter pressure and comfort scores in the forefoot, arch and heel?

The study sought to investigate whether an orthotic stiletto could modulate the pressure and comfort under the forefoot, arch and heel that stiletto wearers experience. Twenty-two women participated. We measured the peak pressure and pressure-time integral for orthotic stilettos with built-in metatarsal pad, heel cup and arch support; standard stilettos without inlays; and trainers. Comfort was recorded during 3 × 3 working days. The orthotic stiletto exhibited lower metatarsal head1 (MTH) and MTH2+3 and heel pressures than the standard stiletto (p < .01), and a long second metatarsal increased MTH2+3 pressure (p < .01). The comfort in the forefoot and heel was higher in the orthotic stiletto than in the standard one (p < .01), and comfort in the forefoot was correlated to the pressure-time integral of MTH2+3 (p = .03) and not peak pressure. Off-the-rack orthotic stilettos can notably reduce plantar pressures and improve forefoot and heel comfort during everyday use. Practitioner Summary: Off-the-rack orthotic stilettos with built-in metatarsal pad, arch support and heel caps can lower the pressure under the heel and forefoot in comparison with a standard stiletto and can improve comfort during everyday use. Having a long second metatarsal is a risk factor for increased forefoot pressure.

Foot internal stress distribution during impact in barefoot running as function of the strike pattern

The aim of the present study is to examine the impact absorption mechanism of the foot for different strike patterns (rearfoot, midfoot and forefoot) using a continuum mechanics approach. A three-dimensional finite element model of the foot was employed to estimate the stress distribution in the foot at the moment of impact during barefoot running. The effects of stress attenuating factors such as the landing angle and the surface stiffness were also analyzed. We characterized rear and forefoot plantar sole behavior in an experimental test, which allowed for refined modeling of plantar pressures for the different strike patterns. Modeling results on the internal stress distributions allow predictions of the susceptibility to injury for particular anatomical structures in the foot.

Balance Improvement Effects of Biofeedback Systems with State-of-the-Art Wearable Sensors: A Systematic Review

Falls and fall-induced injuries are major global public health problems. Balance and gait disorders have been the second leading cause of falls. Inertial motion sensors and force sensors have been widely used to monitor both static and dynamic balance performance. Based on the detected performance, instant visual, auditory, electrotactile and vibrotactile biofeedback could be provided to augment the somatosensory input and enhance balance control. This review aims to synthesize the research examining the effect of biofeedback systems, with wearable inertial motion sensors and force sensors, on balance performance. Randomized and non-randomized clinical trials were included in this review. All studies were evaluated based on the methodological quality. Sample characteristics, device design and study characteristics were summarized. Most previous studies suggested that biofeedback devices were effective in enhancing static and dynamic balance in healthy young and older adults, and patients with balance and gait disorders. Attention should be paid to the choice of appropriate types of sensors and biofeedback for different intended purposes. Maximizing the computing capacity of the micro-processer, while minimizing the size of the electronic components, appears to be the future direction of optimizing the devices. Wearable balance-improving devices have their potential of serving as balance aids in daily life, which can be used indoors and outdoors.

Boot-insole effects on comfort and plantar loading at the heel and fifth metatarsal during running and turning in soccer

Plantar loading may influence comfort, performance and injury risk in soccer boots. This study investigated the effect of cleat configuration and insole cushioning levels on perception of comfort and in-shoe plantar pressures at the heel and fifth metatarsal head region. Nine soccer academy players (age 15.7 ± 1.6 years; height 1.80 ± 0.40 m; body mass 71.9 ± 6.1 kg) took part in the study. Two boot models (8 and 6 cleats) and two insoles (Poron and Poron/gel) provided four footwear combinations assessed using pressure insoles during running and 180° turning. Mechanical and comfort perception tests differentiated boot and insole conditions. During biomechanical testing, the Poron insole generally provided lower peak pressures than the Poron/gel insole, particularly during the braking step of the turn. The boot model did not independently influence peak pressures at the fifth metatarsal, and had minimal influence on heel loads. Specific boot-insole combinations performed differently (P < 0.05). The 8-cleat boot and the Poron insole performed best biomechanically and perceptually, but the combined condition did not. Inclusion of kinematic data and improved control of the turning technique are recommended to strengthen future research. The mechanical, perception and biomechanical results highlight the need for a multi-faceted approach in the assessment of footwear.

The influence of body mass on foot dimensions during pregnancy

In this study, a time-series approach was used to measure women's feet to accurately analyze changes in foot size and body mass during pregnancy. One-hundred women who were pregnant for the first time were asked to respond to questions on subjective complaints of foot discomfort listed in a questionnaire. Among these 100 women, a sample of 30 was obtained and used to measure the women's feet from the twentieth week of the gestation period until labor. The data (from 5 of the 30 women) were used to establish a prediction model for the influence of body mass on changes in foot size during pregnancy. The results indicate that the women subjectively complained that their shoes were too tight, resulting in foot discomfort. From the twentieth to the thirty-eighth week of pregnancy, the average increase in foot length, width, and back foot surface was 0.86 cm (3.6%), 0.25 cm (2.6%), and 18.36 cm(2) (11.9%), respectively. The height of the arch decreased by an average of 0.52 cm (-24.2%). Body mass accounted for more than 90% of the variation (R(2)) in foot dimensions during pregnancy and, thus indicated satisfactory predictive ability. The prediction model developed in this study can serve as a reference for clinical applications and shoe design to prevent women from experiencing extreme discomfort in their feet during pregnancy.

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.

Influence of foot orthosis customisation on perceived comfort during running

Although running is associated with many health benefits, it also exposes the body to greater risk of injury. Foot orthoses are an effective strategy to prevent such injuries. Comfort is an essential element in orthosis design since any discomfort alters the runner's biomechanics, compromising performance and increasing the risk of injury. The present study analyses the perceived comfort of three types of orthoses: custom-made, prefabricated and original running shoe insoles. Nine comfort variables for each insole were assessed in a sample of 40 runners. Custom-made and prefabricated insoles were both perceived as significantly more comfortable than the original insoles. The differences were clinically relevant and were potentially causes of modifications in running gait. Although the prefabricated insoles were rated slightly higher than the custom-made insoles, the differences were not statistically significant. This study shows that prefabricated insoles constitute a reasonable alternative to custom-made insoles in terms of comfort.

PRACTITIONER SUMMARY

The perceived level of comfort of footwear is considered to be a protective measure of the potential risk of running injuries. We here compared runners' perception of comfort of custom-made and prefabricated orthoses while running. We found that even though custom-made orthoses are closely matched to each individual's foot, such customisation does not necessarily imply greater comfort.

Somatosensory perception of running shoe mass

Running shoes are often marketed based on mass. A total of 50 young adult males participated across two separate experiments to determine how well they could perceive the relative masses of five different running shoes using hands versus feet. For the foot portion, subjects were blindly fitted with the shoes and asked to rank their masses individually using visual analogue scales (VAS) and verbal rankings. For the hand portion, two different methods were used, one presenting all shoes simultaneously and the other presenting the shoes individually. Verbal accuracy and VAS scores correlated across subjects for the hand and foot, but accuracy in mass perception by the feet was 30% compared to 92% or 63% by the hand (depending on the method). These results indicate the foot perceives mass poorly compared to the hand, and that consumers' perception of shoe mass may come more from handling shoes versus wearing them.

Testing thermal comfort of trekking boots: an objective and subjective evaluation

The study of the thermal comfort of the feet when using a specific type of shoe is of paramount importance, in particular if the main goal of the study is to attend to the needs of users. The main aim of this study was to propose a test battery for thermal comfort analysis and to apply it to the analysis of trekking boots. Methodologically, the project involves both objective and subjective evaluations. An objective evaluation of the thermal properties of the fabrics used in the boots was developed and applied. In addition, the thermal comfort provided when using the boots was also assessed both subjective and objectively. The evaluation of the thermal comfort during use, which was simulated in a laboratory environment, included the measurement of the temperature and moisture of the feet. The subjective assessment was performed using a questionnaire. From the results obtained, it was possible to define an optimal combination of fabrics to apply to trekking boots by considering the provided thermal insulation, air permeability and wicking. The results also revealed that the subjective perception of thermal comfort appears to be more related to the increase in temperature of the feet than to the moisture retention inside the boot. Although the evaluation of knits used in the boots indicated that a particular combination of fibres was optimal for use in the inner layer, the subjective and objective evaluation of thermal comfort revealed that the evaluation provided by users did not necessarily match the technical assessment data. No correlation was observed between the general comfort and specific thermal comfort assessments. Finally, the identification of thermal discomfort by specific foot areas would be useful in the process of designing and developing boots.

A model for the perception of surface pressure on human foot

The psychophysical relationship between the magnitude of pressure on thirteen test locations of twenty healthy subjects' feet with four probe areas at three indentation speeds and the corresponding perceived sensations were analyzed. The dependency of pressure pain thresholds (PPT) on area, A, and speed, v, can be mathematically modeled in the form, PPT(i) = [a(i) + bLn(v)]A(β)i = 1,2…13 where β and b are constants and are dependent on location and gender, and a(i) is a constant highly correlated with foot tissue stiffness. The relationship between the sensory intensity to pressure magnitude appears to follow a modified Stevens' power law with power exponents less than 1.0 and consistent across the 13 test locations with a mean of 0.82 and a range from 0.67 to 0.98. This particular model helps to understand the sensation of pressure threshold and its impact in the design of consumer products.

Pressure thresholds of the human foot: measurement reliability and effects of stimulus characteristics

Information related to reliable values of discomfort thresholds can help to improve the designs of various products. This study aimed to investigate the measurement reliabilities associated with pressure thresholds, while determining the effects of stimulus characteristics (stimulus area, indentation speed) of the human foot. An indentation apparatus was used with four sizes of indentation probes and three indentation speeds. In total, 13 locations on the right foot of 10 male and 10 female participants were tested to determine the pressure discomfort thresholds (PDT) and pressure pain thresholds (PPT). Results show that the tests had very good measurement reliability with intra-class correlations (ICC) greater than 0.8 for the PPT measurements and acceptable reliability (most ICC > 0.75, with a few between 0.5 and 0.75) for the PDT measurements, demonstrating that participants are capable of judging their pain and discomfort thresholds. Pressure sensitivity differs across locations of the foot, with the medial plantar arch of the foot being the most sensitive, followed by the dorsal surface of the foot. The heel area was the least sensitive. PPT and PDT are dependent on the stimulus characteristics of the area and the speed of indentation. A smaller area has a higher PPT and PDT, indicating significant effects of spatial summation. The increase of PDT and PPT at higher speeds may be partially explained by the increase in stiffness because foot tissue exhibits viscoelastic properties. The findings can have a significant impact on the design of footwear and other accessories for improved foot health and comfort. Statement of Relevance: This study investigated the threshold measurement reliability while determining the pressure sensitivity on the surface of the foot with varying stimulus characteristics. The findings may be very useful in the design of footwear and other accessories for improved comfort and reduced injuries.

A comparison between Chinese and Caucasian head shapes

Univariate anthropometric data have long documented a difference in head shape proportion between Chinese and Caucasian populations. This difference has made it impossible to create eyewear, helmets and facemasks that fit both groups well. However, it has been unknown to what extend and precisely how the two populations differ from each other in form. In this study, we applied geometric morphometrics to dense surface data to quantify and characterize the shape differences using a large data set from two recent 3D anthropometric surveys, one in North America and Europe, and one in China. The comparison showed the significant variations between head shapes of the two groups and results demonstrated that Chinese heads were rounder than Caucasian counterparts, with a flatter back and forehead. The quantitative measurements and analyses of these shape differences may be applied in many fields, including anthropometrics, product design, cranial surgery and cranial therapy.

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.