Relationship between plantar pressure distribution under the foot and insole comfort

Autonomic responses to pressure sensitivity of head, face and neck: Heart rate and skin conductance

Subjective scales are frequently used in the design process of head-related products to assess pressure discomfort. Nevertheless, some users lack fundamental cognitive and motor abilities (e.g., paralyzed patients). Therefore, it is vital to find non-verbal measurements of pressure discomfort and pressure pain. This study gathered the autonomic response data (heart rate and skin conductance) of 30 landmarks in head, neck and face from 31 participants experiencing pressure discomfort and pressure pain. The results indicate that pressure stimulation can change heart rate (HR) and skin conductance (SC). SC can be more useful in assessing pressure discomfort than HR for specific landmarks, and SC also possesses a faster arousal rate than HR. Moreover, HR decreased in response to pressure stimulation, while SC decreased followed by an increase. In comparisons between genders, the subjective pressure discomfort threshold (PDT) and pressure pain threshold (PPT) of women were lower than those of men, but men's autonomic responses (HR and SC) were more intense. Furthermore, there was no linear correlation between subjective pressure thresholds (PDT and PPT) and autonomic response intensity. This study has significant implications for resolving ergonomic issues (pressure discomfort and pain) associated with head-related products.

Analysis of mechanical characteristics of walking and running foot functional units based on non-negative matrix factorization

Objective: To explore the characteristics of Non-Negative Matrix Factorization (NNMF) in analyzing the mechanical characteristics of foot functional units during walking and running. Methods: Eighteen subjects (9 males and 9 females) were recruited, and the ground reaction force curves of each foot region during walking and running were collected using a plantar pressure measurement system. NNMF was used to extract the mechanical features of different foot regions and to determine the number of foot functional units. The differences between the base matrices of walking and running were compared by traditional t-tests, and the differences in coefficient matrices were compared by one-dimensional statistical parameter mapping. Results: 1) When the number of foot functional units for walking and running were both 2, the Variability Accounted For (VAF) by the matrix exceeded 0.90 (VAF walk = 0.96 ± 0.02, VAF run = 0.95 ± 0.04); 2) In foot functional unit 1, both walking and running exhibited buffering function, with the heel region being the main force-bearing area and the forefoot also participating in partial buffering; 3) In foot functional unit 2, both walking and running exhibited push-off function, with the middle part of the forefoot having a higher contribution weight; 4) In foot functional unit 1, compared to walking, the overall force characteristics of the running foot were greater during the support phase of the 0%-20% stage, with the third and fourth metatarsal areas having higher contribution weights and the lateral heel area having lower weights; 5) In foot functional unit 2, compared to walking, the overall force was higher during the beginning and 11%-69% stages of running, and lower during the 4%-5% and 73%-92% stages. During running, the thumb area, the first metatarsal area and the midfoot area had higher contribution weights than during walking; in the third and fourth metatarsal areas, the contribution weights were lower during running than during walking. Conclusion: Based on the mechanical characteristics of the foot, walking and running can both be decomposed into two foot functional units: buffering and push-off. The forefoot occupies a certain weight in both buffering and push-off functions, indicating that there may be a complex foot function transformation mechanism in the transverse arch of foot. Compared to walking, running completes push-off earlier, and the force region is more inclined towards the inner side of the foot, with the hallux area having a greater weight during push-off. This study suggests that NNMF is feasible for analyzing foot mechanical characteristics.

Evaluating wrapping alpine ski boots during on-snow carving

Introduction

Alpine ski boots enable rapid and precise force transfer between skier and ski while carving. These boots are made of rigid plastic and fit tightly commonly through four buckles. Such a fit can improve speed and control but also pain and discomfort. In athletic footwear, alterations to the upper designed to wrap the foot improve performance during rapid changes of direction and during trail running. The purpose of this study was to systematically evaluate the performance and fit of two different ski boot shell closure mechanisms: a BOA closure and a Buckle closure.

Materials and methods

This was a two-part study with 22 subjects performing on-mountain skiing and 10 of those subjects completing an in-laboratory pressure evaluation. Subjects skied in both boots three times each while data from inertial measurement units (IMUs) and plantar pressures were collected along with subjective data. In lab, static dorsal and plantar pressures were collected while the subjects flexed into the boots.

Results

The BOA boots improved subjective and objective ski performance; qualitative carving scores were greater, likely through increasing the amount of normal force applied to the ski while turning. There were no differences in edge angles between the boots, as computed from IMUs. The BOA boot also reduced static peak plantar pressures in the rearfoot along with reducing overall static pressure on the dorsum as compared with the Buckle boot.

Conclusions

This is the first study to systematically evaluate differences in ski boot closures. The improvements in carving performance in the BOA boot are supported by distinct differences in pressure distribution within each boot, which we speculate contributed to improved performance by reducing discomfort or pain while still facilitating effective force transfer.

The Soft Prefabricated Orthopedic Insole Decreases Plantar Pressure during Uphill Walking with Heavy Load Carriage

This study aimed to investigate the effect of varying the hardness of prefabricated orthopedic insoles on plantar pressure and muscle fatigue during uphill walking with a heavy backpack. Fifteen healthy male recreational athletes (age: 20.4 ± 1.0 years, height: 176.9 ± 5.7 cm, weight: 76.5 ± 9.0 kg) wore prefabricated orthopedic insoles with foot arch support; a heel cup with medium (MI), hard (HI), and soft (SI) relative hardnesses; and flat insoles (FI). They performed treadmill walking on uphill gradients with 25 kg backpacks. The plantar pressure and surface electromyographic activity were recorded separately, in 30 s and 6 min uphill treadmill walking trials, respectively. The HI, MI, and SI significantly decreased peak plantar pressure in the lateral heel compared to FI. The MI and SI significantly decreased the peak plantar pressure in the fifth metatarsal compared to FI. The MI significantly reduced the pressure–time integral in the lateral heel compared to FI. The HI significantly increased the peak plantar pressure and pressure–time integral in the toes compared to other insoles, and decreased the contact area in the metatarsal compared to SI. In conclusion, a prefabricated orthopedic insole made of soft material at the fore- and rearfoot, with midfoot arch support and a heel cup, may augment the advantages of plantar pressure distribution during uphill weighted walking.

Evaluating footwear "in the wild": Examining wrap and lace trail shoe closures during trail running

Trail running participation has grown over the last two decades. As a result, there have been an increasing number of studies examining the sport. Despite these increases, there is a lack of understanding regarding the effects of footwear on trail running biomechanics in ecologically valid conditions. The purpose of our study was to evaluate how a Wrap vs. Lace closure (on the same shoe) impacts running biomechanics on a trail. Thirty subjects ran a trail loop in each shoe while wearing a global positioning system (GPS) watch, heart rate monitor, inertial measurement units (IMUs), and plantar pressure insoles. The Wrap closure reduced peak foot eversion velocity (measured via IMU), which has been associated with fit. The Wrap closure also increased heel contact area, which is also associated with fit. This increase may be associated with the subjective preference for the Wrap. Lastly, runners had a small but significant increase in running speed in the Wrap shoe with no differences in heart rate nor subjective exertion. In total, the Wrap closure fit better than the Lace closure on a variety of terrain. This study demonstrates the feasibility of detecting meaningful biomechanical differences between footwear features in the wild using statistical tools and study design. Evaluating footwear in ecologically valid environments often creates additional variance in the data. This variance should not be treated as noise; instead, it is critical to capture this additional variance and challenges of ecologically valid terrain if we hope to use biomechanics to impact the development of new products.

Effects of three-dimensional image based insole for healthy volunteers: a pilot clinical trial

Insoles are used to treat various foot diseases, including plantar foot, diabetic foot ulcers, and refractory plantar fasciitis. In this study, we investigated the effects of 3-dimensional image-based (3-D) insole in healthy volunteers with no foot diseases. Additionally, the comfort of the 3-D insole was compared with that of a custom-molded insole. A single-center, randomized, open clinical trial was conducted to address the effectiveness of insole use in a healthy population with no foot or knee disease. Two types of arch support insoles were evaluated for their effectiveness: a 3-D insole and a custom-molded insole. Fifty Korean volunteers participated in the study and were randomly allocated into the "3-D insole" (n = 40) or "custom-molding insole" (n = 10) groups. All subjects wore 3-D insoles or custom-molded insoles for 2 weeks. The sense of wearing shoes (Visual Analog Scale [VAS] and score) and fatigue of the foot were used to assess the insole effects at the end of the 2-week study period. The 3-D insole groups showed significantly improved sense of wearing shoes (VAS, p = 0.0001; score, p = 0.0002) and foot fatigue (p = 0.0005) throughout the study period. Although the number of subjects was different, the custom-molding insole group showed no significant changes in the sense of wearing shoes (VAS, 0.1188; score, p = 0.1483). Foot fatigue in the 3-D insole group improved significantly (p = 0.0005), which shows that a 3-D insole might have favorable effects on foot health in a healthy population.

Trial Registration

Clinical Research Information Service Identifier: KCT0008100.

Physical Property of 3D-Printed N-Pointed Star-Shaped Outsole Prepared by FDM 3D Printer Using the Lightweight TPU

This investigation has shown the feasibility of modulation in physical properties for multiple outsole designs with 3-, 4-, and 6-pointed star-shaped patterns and various thicknesses for 5, 7.5, and 10 mm, which were fabricated with a FDM 3D printer using lightweight TPU filament, where the physical and foot pressure distribution properties were evaluated to confirm the best quality and comfort outsole. Through varying the structural pattern designs in combination with optimal 3D-printing parameters, the physical properties of the TPU LW-3, 4, and 6-PS outsoles were confirmed with enhanced properties along with increased thicknesses. In this study, the morphology images revealed a lower foaming state, a better-fused interlayer, and fewer microvoids in the TPU LW-3, 4, and 6-PS outsole, as the thickness developed, indicating enhanced density and rigidity. The best physical property was confirmed at LW 3-PS-10 with 0.706 specific gravity, 68.3 g weight, 0.232 static coefficient and 0.199 dynamic coefficient, 236% NSB abrasion, 127 DIN abrasion, 30% ball drop and 28% pendulum resilience, verifying the most high-quality, safe, and durable prototype. Regarding comfort, the 3-PS-10 also was regarded as comfortable concerning the wearable parts by virtue of its excellent physical properties, as well as its having the largest pressure area and the lower pressure force; meanwhile, the 4PS and 6PS also exhibited similar conditions for different thicknesses. Since not much distinct difference in pressure distribution compared to others was exhibited, it is suggested to explore optimization solutions to update the comfort of the footwear in future research.

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.

Body-Temperature Programmable Soft-Shape Memory Hybrid Sponges for Comfort Fitting

Porous shape memory hybrids are fabricated with different matrix (silicone) hardness and different inclusion (polycaprolactone, PCL) ratios. They are characterized to obtain their mechanical response to cyclic loads (with/without pre-straining/programming) and their shape memory performances after body-temperature programming are investigated. These materials are lightweight due to their porous structures. Wetted hydrogels used in the fabrication process for creating pores are reusable and hence this process is eco-friendly. These porous shape memory hybrids exhibit the good shape memory effect of around 90% with higher inclusion (PCL) ratios, which is better than the solid versions reported in the literature. Hence, it is concluded that these materials have great potential to be used in, for instance, insoles and soles for comfort fitting, as demonstrated.

Physical performance and perception of foot discomfort during a soccer-specific match simulation. A comparison of football boots

Football boots are marketed with emphasis on a single key performance characteristic (e.g. speed). Little is known on how design parameters impact players' performance. This study investigated the impact of boot design on performance maintenance and perceived foot comfort during a 90-minute match simulation drill. Eleven male university football players tested two commercially available "sprint boots" known to generate significantly different plantar pressures (high=Boot H and low=Boot L) . Players completed a modified Soccer-specific Aerobic Field Test on a 3G pitch. Heart rate, rated perceived exertion and perceived foot discomfort were assessed for each 15-min interval. Power generation was assessed pre- and post-match simulation. A significantly higher mean heart rate was seen for Boot L in the 60th-75th and 75th-90th minute intervals (P = 0.017, P = 0.012 respectively). Perceived exertion did not differ between boots (P ≥ 0.302). Power generation significantly decreased in Boot H between pre- and post-match (P = 0.042). Both boots increased discomfort with significantly more plantar discomfort felt in the last 30 min in Boot H (75th min: P = 0.037; 90th min: P = 0.048). The results imply that a comfortable boot design may improve maintenance of performance during match-play.

Towards Customized Footwear with Improved Comfort

A methodology enabling the customization of shoes for comfort improvement is proposed and assessed. For this aim, 3D printed graded density inserts were placed in one of the critical plantar pressure zones of conventional insoles, the heel. A semi-automated routine was developed to design the 3D inserts ready for printing, which comprises three main stages: (i) the definition of the number of areas with different mesh density, (ii) the generation of 2D components with continuous graded mesh density, and (iii) the generation of a 3D component having the same 2D base mesh. The adequacy of the mesh densities used in the inserts was previously assessed through compression tests, using uniform mesh density samples. Slippers with different pairs of inserts embedded in their insoles were mechanically characterized, and their comfort was qualitatively assessed by a panel of users. All users found a particular pair, or a set, of prototype slippers more comfortable than the original ones, taken as reference, but their preferences were not consensual. This emphasizes the need for shoe customization, and the usefulness of the proposed methodology to achieve such a goal.

An individually moulded insole with 5-mm medial arch support reduces peak impact and loading at the heel after a one-hour treadmill run

BACKGROUND

Foot pain experienced by long-distance runners could be relieved by functional insoles which aim at evenly distributing the plantar pressure.

RESEARCH QUESTION

We hypothesised that an individually moulded insole with medial arch support would reduce the impact and loading under the heel and metatarsal regions.

METHODS

Twelve male recreational runners ran on a treadmill at 10 km/h for 1 hour with flat insoles and medial arch supported insoles. A pressure insole system (Novel Pedar, Germany) was used to obtain the peak pressure, peak force, time normalised pressure-time integrals, and the percentage of the total force-time integrals under 10 regions.

RESULTS

Medial arch supported insoles reduced the peak force under the heel (medial: -15.3%, p = 0.001; lateral: -19.2%, p = 0.037) during the initial run, and reduced peak pressure under the heel (medial: -13.3%, p = 0.005; lateral: -9.9%, p = 0.006), and peak force under the medial heel (-17.8%, p = 0.006) after the run. The percentage of the total force-time integrals under the heel was reduced (medial: -23.8%, p = 0.004; lateral: -13.6%, p = 0.022) after the run. No significant difference was found under the metatarsal regions. There is shift of load from the metatarsal regions to the medial mid-foot as indicated by the change of the percentage of total force-time integrals.

SIGNIFICANCE

Medial arch supported insoles were effective in reducing the impact and loading under the heel region in prolonged running on a treadmill.

LEVEL OF EVIDENCE

Controlled laboratory study, Level V.

Development and evaluation of a dual density insole for people standing for long periods of time at work

BACKGROUND

Appropriate footwear is important for those who stand for prolonged periods of time at work, enabling them to remain comfortable, healthy and safe. Preferences for different footwear cushioning or hardness are often person specific and one shoe or insole will not be the choice for all. The aim of this study was to develop a range of insole options to maintain comfort during long periods of standing at work and test insole material preferences in the workplace.

METHODS

The study consisted of two parts. Part one evaluated 9 insoles of the same geometry that varied in hardness under 2 different plantar regions (n = 34). Insole preference, plantar pressure and selected anthropometric foot measures were taken. Three insole designs based on the most preferred options were identified from this part. In part two, these three insoles were evaluated with 22 workers immediately after trying them on (1 min) and after a working day. Foot anthropometric measures and subjective questions concerning material hardness preferences and self-reported foot characteristics were used to investigate whether either had a relationship with insole preference.

RESULTS

Part one found insole preference predominantly varied according to material hardness under the medial arch rather than the heel/forefoot. Softer material under the heel and forefoot was associated with a reduction in peak pressures in these regions (p < 0.05). The most preferred insole had lower pressures under the hallux and first metatarsal phalangeal joint, and greater pressures and contact area under the medial midfoot (p < 0.05) compared to the least preferred insole. Height and foot anthropometrics were related to insole preference. In part two, under real world conditions, insole preference changed for 65% of participants between the immediate assessment (1 min) and after a whole workday, with dorsum height related to the latter (p < 0.05). Subjective questions for self-assessed arch height and footwear feel identified 66.7% of the insole preferences after 1 day at work, compared to 36% using immediate assessment of insole preference.

CONCLUSION

Preference for material hardness varies underneath the medial arch of the foot and is time dependent. Simple foot measures and questions about comfort can guide selection of preferred insoles.

Acute effect of engineered thermoplastic polyurethane elastomer knockoff running footwear on foot loading and comfort during heel-to-toe running

BACKGROUND

Better midsole materials and comfort have been incorporated into more expensive shoes and are popular with runners. Consequently, knockoff running shoes are currently widely distributed in the Chinese market and and cost only 30%-50% of the total price of genuine branded products.

RESEARCH QUESTION

Uncertainty exists concerning the beneficial effects of advanced shoe material application in decreasing foot loading or impact force during running. Additionally, using comfort as a criterion to identify genuine branded running shoes may exclude brand factor.

METHODS

Fifteen healthy male volunteers were asked to perform two different tests, including running and a comfort evaluation. Each participant was asked to identify which footwear was the Adidas brand shoe based on their perception of comfort.

RESULTS

Time to the first peak of the vertical ground reaction force occurred significantly later when subjects wore the genuine branded shoe compared to knockoff shoe 1 (p = 0.003) and knockoff shoe 2 (p = 0.015) footwea. The genuine branded shoe (p = 0.005) and knockoff shoe 1 (p = 0.029) were significantly more comfortable compared to the knockoff shoe 2. Only four subjects selected the genuine branded shoe, whereas six subjects selected both the genuine branded shoe and knockoff shoe 1.

SIGNIFICANCE

Knockoff running footwear significantly increases impact loading compared to the genuine branded product, thereby posing greater risk of running injury.

Are custom-made foot orthoses of any interest on the treatment of foot pain for prolonged standing workers?

BACKGROUND

The prolonged standing position is an important factor in the onset of foot musculoskeletal disorders among workers. Safety shoes, designed to protect against the physical constraints of the work environment, do not address this issue to date.

OBJECTIVES

The goal of this study is to assess the possible benefits of custom-made foot orthoses among prolonged standing workers.

STUDY DESIGN

repeated measures without control group.

METHODS

Thirty-four standing workers who suffer from foot pain volunteered for the study. Custom-made foot orthoses, designed by a podiatrist, were 3D-printed and distributed to each volunteer. Static balance as well as static and dynamic plantar pressure measurements were carried out with sensors inserted in the safety shoes, before and after three weeks of wearing foot orthoses daily. A questionnaire on pain and comfort was also distributed before and after treatment.

RESULTS

Feelings of pain, discomfort and heavy legs were found to be significantly reduced after wearing 3D-printed orthoses (p<0.05). Additionally, in static and dynamic conditions, a significant decrease in mean peak pressure in the rearfoot area was observed along with a significant increase in mean peak pressure in the midfoot area (p<0.05). There was also a significant improvement of balance in the medial-lateral direction.

CONCLUSION

Custom-made orthoses significantly increase the well-being of standing workers in our experimental testing conditions. The custom-made shape allows for a better balanced distribution of foot peak pressure thanks to its support and stimulation of the foot arches particularly through a shift of pressure from the heel to the midfoot.

Shoe Cushioning Effects on Foot Loading and Comfort Perception during Typical Basketball Maneuvers

Purpose: This study aimed to explore the relationship between foot loading and comfort perception in two basketball shoes during basketball-specific maneuvers. Methods: Twelve male collegiate basketball players were required to complete three basketball maneuvers (i.e., side-step cutting, 90° L-direction running, and lay-up jumping) in two basketball shoe conditions (shoe L and shoe N, with different midsole cushioning types). Two Kistler force plates and a Medilogic insole plantar pressure system were used to collect kinetic data (i.e., impact force, peak loading rate, and plantar pressure variables). Perception scales were used to evaluate comfort perception. Results: No significant difference was observed between the two shoes during maneuvers in terms of ground reaction force. However, the plantar pressure of shoe L in the midfoot and lateral foot regions was significantly greater than that of shoe N during side-step cutting and lay-up jumping. Shoe N was significantly superior to shoe L, especially in dynamic scale in terms of the perception of comfort. The plantar pressure and perception characteristics in the two shoes were significantly different but inconsistent with each other. Conclusion: The biomechanical characteristics of the shoes themselves and the perception evaluation of the athletes should be considered in comprehensive shoe-cushioning design and evaluation.

Does enhanced footwear comfort affect oxygen consumption and running biomechanics?

Comfort as an essential parameter for running footwear is gaining importance in footwear research and development, and has also been proposed to decrease injury rate and improve metabolic demand in the paradigm of the comfort filter. The aims of this study were to determine differences in oxygen consumption and biomechanical variables associated with lower extremity injuries in response to running shoes of differing comfort. Fifteen male runners attended two testing sessions including an incremental lactate threshold test, a comfort assessment and treadmill running trials for the biomechanical and physiological measurements. Statistical analyses were performed on oxygen consumption, spatio-temporal variables including foot-ground angle and coupling angle variability of 12 couplings in five stride phases. No decrease in oxygen consumption was found in the most preferred shoe condition. Investigation of potential biomechanical contributors to changes in metabolic demands revealed differences in the stride rate between the most and least preferred condition. In coupling angle variability analyses, only one coupling (ankle dorsiflexion/plantarflexion to knee varus/valgus) yielded a significant difference between conditions in the phase including the touch down. Based on the findings of this study, previous suggestions regarding positive effects of enhanced footwear comfort during running cannot be supported - neither on economy nor on injury prevention perspective. However, a prospective study of lower extremity injury combined with measurements of biomechanical and physiological variables seems to be required for a definite support or contradiction of the comfort filter.

Changes in calcaneal pitch and heel fat pad thickness in static weight bearing radiographs while wearing shoes with arch support and heel cup orthotics

Background

Foot orthoses have been shown to reduce the collapse of the longitudinal arch and to constrain soft tissue displacement under the heel. However, there has not been a study that has shown the effectiveness of both the arch and heel features in the same orthosis. This study quantitatively analyzed if the calcaneal pitch and the heel pad thickness will be affected by the use of an arch support and heel cup insole in a static weightbearing stance while wearing sports shoes.

Methods

Twenty-four (24) feet from 12 elite-level female soccer players with a mean age of 25 ± 3.99 years (20–33 years old) were studied. Lateral weightbearing radiographs with and without orthotics were obtained in order to measure the calcaneal pitch angle and heel fat pad thickness for each foot. A subjective outcome measure was used and the scores were classified as bad (0–2), fair (3–5), good (6–8), or excellent (9-10).

Results

The calcaneal pitch angle increased in all but three cases by an average of 1.05° (range, −1.14 to 3.19) after wearing orthotics (p < 0.01). The heel fat pad thickness increased in all cases with an average of 1.25 mm (range, 1.05 to 1.47; p < 0.01)). 9 of 12 subjects (75%) reported excellent (n = 2) or good (n = 7) overall subjective scores with insole wear.

Conclusion

Under static weightbearing conditions, the arch support and heel cup features of a foot orthosis help improve the height of the calcaneal pitch and the thickness of the heel fat pad, respectively.

Effect produced on ground reaction forces by a prefabricated, weight-bearing and non-weight-bearing foot orthosis in the treatment of pronated foot: Pilot study

BACKGROUND

The aim of this study is to explore the changes in ground reaction force (GRF) produced by custom-made weight-bearing and nonweight-bearing foot orthoses and by a prefabricated foot orthosis, in the control of the pronated foot.

METHODS

Thirty-nine participants were recruited. All were in good health, aged 18 to 25 years, and presented pronated foot. Three different types of foot orthosis were studied: prefabricated, weight-bearing, and nonweight-bearing.

RESULTS

No significant differences were observed in the phases of the gait cycle between the prefabricated, the weight-bearing, and the nonweight-bearing foot orthoses.

CONCLUSIONS

Neither prefabricated insoles nor custom-made orthoses (weight-bearing or nonweight-bearing) modified GRF.

Biomechanical Variations in Female Runner’s Pre and Post Treadmill Running

The growing popularity of endurance sports activities is associated with a growing number of running injuries among recreational runners. The aim of this study was to assess the kinematic and kinetic variation on biomechanical parameters before and after 5km of treadmill running in female runners. Fourteen habitually shod female runners were assessed during treadmill running at their self-selected 5km running speed. A VICON motion analysis system and a Novel Pedar insole plantar pressure measurement system were used to record kinematic and plantar pressure data. Key findings from the study were that the internal and external rotation angle of the ankle, hip and knee while pre-5k running showed significant differences to those evaluated post-5k. The peak values of ground reaction forces (GRF) recorded pre-5k running were larger than the forces measured post-5k running. Combining the inversion and eversion of the ankle in the coronal plane during the pushing off phase, post-5k running showed a bigger eversion angle than pre-5k running. These subtle differences may reflect adaptation of motor control in female runners during long distance running of 5km.

Current Soccer Footwear, Its Role in Injuries and Potential for Improvement

Soccer is the most popular sport in the world and generates great financial revenue. It is also a sport whose practice has evolved considerably in terms of intensity and commitment, and in which the intrinsic risk of injury (not directly related to an interaction with the environment) is particularly high. In this context, the cleated shoe as a major component of soccer equipment may play a key role in the overexposure to injury. Soccer shoe evolution is all the more challenging, because design and mechanical structure differ in many points compared to other modern shoes developed for sports such as running, tennis and basketball. This critical review aims to elucidate the characteristics of modern soccer footwear and their possible link to soccer-specific injuries, focusing on the following areas: (1) ergonomics, comfort and proprioception; (2) shoe mechanical characteristics; (3) field surfaces and shoe design.

The biomechanical effects and perceived comfort of textile-fabricated insoles during straight line walking

BACKGROUND

Orthotic insoles that are made of foam material often have less breathability and thus cause discomfort to the wearer. Given that a sandwich structure offers better porosity and breathability that would improve comfort, the impact of custom-made insoles made with three-dimensional spacer fabric is studied.

OBJECTIVES

To examine the biomechanical effects and subjective comfort of spacer-fabric insoles during walking.

STUDY DESIGN

Repeated measures.

METHODS

Plantar pressure and lower limb muscle activity data are collected from 12 subjects. Subjective perceived comfort is measured after five successful walking trials for each of the three different insoles worn: traditional insoles made with ethylene vinyl acetate and two types of spacer-fabric insoles.

RESULTS

Compared to the use of traditional insoles, there is a statistically significant reduction in the peak pressure (>8%) and pressure-time integral (>16%) in the toes and metatarsal head 1 with the use of the spacer-fabric insoles as the top layer. Insoles with two layers of spacer fabrics have the highest perceived comfort ( p < 0.01). However, there is no significant difference in the selected muscle activity for all three insoles.

CONCLUSION

Insoles with different arrangements of spacer fabrics allow changes in pressure patterns across the plantar foot and perception of comfort while walking. The findings enhance current understanding on the use of textile-fabricated materials, which provide alternative solutions for modifying insoles. Clinical relevance The key features of spacer fabric offer a viable option for different orthotic insole applications. The results will greatly contribute toward insole prescription, potentially enhancing the efficacy of orthotic performance and increasing the range of insole materials.

Elastic Shape Memory Hybrids Programmable at Around Body-Temperature for Comfort Fitting

A series of silicone based elastic shape memory hybrids are fabricated. Their shape memory performance, mechanical behaviors at room temperature with/without programming and during fitting at 37 °C are investigated. It is found that these materials have good shape memory effect and are always highly elastic. At 37 °C, there are 10 min or more for fitting. Thus, it is concluded that this type of material has great potential as an elastic shape memory material for comfort fitting.

Hardness and posting of foot orthoses modify plantar contact area, plantar pressure, and perceived comfort when cycling

OBJECTIVES

To evaluate the effects of hardness and posting of orthoses on plantar profile and perceived comfort and support during cycling.

DESIGN

A repeated measures study with randomised order of orthoses, hardness, and posting conditions.

METHODS

Twenty-three cyclists cycled at a cadence of 90rpm and a perceived exertion rating of twelve. Contoured soft and hard orthoses with or without a medial forefoot or lateral forefoot post were evaluated. Plantar contact area, mean pressure and peak pressure were measured for nine plantar regions using the pedar^®-X system and represented as a percentage of the total (CA%, MP%, and PP% respectively). Perceived comfort and support was rated on a visual analogue scale.

RESULTS

The softer orthosis significantly increased CA% (p=0.014) across the midfoot and heel with a decrease in the toe region and forefoot. MP% (p=0.034) and PP% (p=0.012) were significantly increased at the mid and lateral forefoot with reductions in MP% at the midfoot and in PP% at the hallux and toes. Forefoot posting significantly increased CA% (p=0.018) at the toes and forefoot and decreased it at the heel. PP% was significantly altered (p=0.013) based on posting position. Lateral forefoot posting significantly decreased heel comfort (p=0.036).

CONCLUSION

When cycling, a soft, contoured orthosis increased contact across the midfoot and heel, modulating forefoot and midfoot plantar pressures but not altering comfort or support. Forefoot postings significantly modified contact areas and plantar pressures and reduced comfort at the heel.

Comparison of plantar pressure distribution between three different shoes and three common movements in futsal

INTRODUCTION

Analysis of in-shoe pressure distribution during sport-specific movements may provide a clue to improve shoe design and prevent injuries. This study compared the mean and the peak pressures over the whole foot and ten separate areas of the foot, wearing different shoes during specific movements.

METHODS

Nine male adult recreational futsal players performed three trials of three sport-specific movements (shuffle, sprint and penalty kick), while they were wearing three brands of futsal shoes (Adidas, Lotto and Tiger). Plantar pressures on dominant feet were collected using the F-SCAN system. Peak and mean pressures for whole foot and each separate area were extracted. For statistical analysis, the mean differences in outcome variables between different shoes and movements were estimated using random-effects regression model using STATA ver.10.

RESULTS

In the average calculation of the three movements, the peak pressure on the whole foot in Adidas shoe was less than Lotto [8.8% (CI95%: 4.1-13.6%)] and Tiger shoes [11.8% (CI95%:7-16.7%)], (P<0.001). Also, the recorded peak pressure on the whole foot in penalty kick was 61.1% (CI95%: 56.3-65.9%) and 57.6% (CI95%: 52.8-62.3%) less than Shuffle and Sprint tests, respectively (P<0.001).

CONCLUSION

Areas with the highest peak pressure during all 3 movements were not different between all shoes. This area was medial forefoot in cases of shuffle and sprint movements and medial heel in case of penalty kick.

Flip-flop footwear with a moulded foot-bed for the treatment of foot pain: a randomised controlled trial

Background

Foot pain is a common problem affecting up to 1 in 5 adults and is known to adversely affect activities of daily living and health related quality of life. Orthopaedic footwear interventions are used as a conservative treatment for foot pain, although adherence is known to be low, in part due to the perception of poor comfort and unattractiveness of the footwear. The objective of this trial was to assess the efficacy of flip-flop style footwear (Foot Bio-Tec©) with a moulded foot-bed in reducing foot pain compared to participant’s usual footwear.

Methods

Two-arm parallel randomised controlled trial using computer generated random allocation schedule at an Australian university podiatry clinic. 108 volunteers with disabling foot pain were enrolled after responding to an advertisement and eligibility screening. Participants were randomly allocated to receive footwear education and moulded flip-flop footwear to wear as much as they were comfortable with for the next 12 weeks (n = 54) or footwear education and instructions to wear their normal footwear for the next 12 weeks (n = 54). Primary outcome was the pain domain of the Foot Health Status Questionnaire (FHSQ). Secondary outcomes were the foot function and general foot health domains of the FHSQ, a visual analogue scale (VAS) for foot pain and perceived comfort of the intervention footwear.

Results

Compared to the control group, the moulded flip-flop group showed a significant improvement in the primary outcome measure of the FHSQ pain domain (adjusted mean difference 8.36 points, 95 % CI 5.58 to 13.27, p < 0.01). Statistical and clinically significant differences were observed for the secondary measure of foot pain assessed by a VAS and the FSHQ domains of foot function and general foot health. None of the participants reported any pain or discomfort from the intervention footwear and six (footwear group = 4) were lost to follow up.

Conclusions

Our results demonstrate that flip-flop footwear with a moulded foot-bed can have a significant effect on foot pain, function and foot health and might be a valuable adjunct therapy for people with foot pain.

Trial registration

ACTRN12614000933651. Retrospectively registered: 01/09/2014.

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.

Can subjective comfort be used as a measure of plantar pressure in football boots?

Comfort has been shown to be the most desired football boot feature by players. Previous studies have shown discomfort to be related to increased plantar pressures for running shoes which, in some foot regions, has been suggested to be a causative factor in overuse injuries. This study examined the correlation between subjective comfort data and objective plantar pressure for football boots during football-specific drills. Eight male university football players were tested. Plantar pressure data were collected during four football-specific movements for each of three different football boots. The global and local peak pressures based on a nine-sectioned foot map were compared to subjective comfort measures recorded using a visual analogue scale for global discomfort and a discomfort foot map for local discomfort. A weak (r_s = -0.126) yet significant (P < 0.05) correlation was shown between the peak plantar pressure experienced and the visual analogue scale rated comfort. The model only significantly predicted (P > 0.001) the outcome for two (medial and lateral forefoot) of the nine foot regions. Subjective comfort data is therefore not a reliable measure of increased plantar pressures for any foot region. The use of plantar pressure measures is therefore needed to optimise injury prevention when designing studded footwear.

Validity and repeatability of three in-shoe pressure measurement systems

In-shoe pressure measurement devices are used in research and clinic to quantify plantar foot pressures. Various devices are available, differing in size, sensor number and type; therefore accuracy and repeatability. Three devices (Medilogic, Tekscan and Pedar) were examined in a 2 day×3 trial design, quantifying insole response to regional and whole insole loading. The whole insole protocol applied an even pressure (50-600kPa) to the insole surface for 0-30s in the Novel TruBlue™ device. The regional protocol utilised cylinders with contact surfaces of 3.14 and 15.9cm(2) to apply pressures of 50 and 200kPa. The validity (% difference and Root Mean Square Error: RMSE) and repeatability (Intra-Class Correlation Coefficient: ICC) of the applied pressures (whole insole) and contact area (regional) were outcome variables. Validity of the Pedar system was highest (RMSE 2.6kPa; difference 3.9%), with the Medilogic (RMSE 27.0kPa; difference 13.4%) and Tekscan (RMSE 27.0kPa; difference 5.9%) systems displaying reduced validity. The average and peak pressures demonstrated high between-day repeatability for all three systems and each insole size (ICC≥0.859). The regional contact area % difference ranged from -97 to +249%, but the ICC demonstrated medium to high between-day repeatability (ICC≥0.797). Due to the varying responses of the systems, the choice of an appropriate pressure measurement device must be based on the loading characteristics and the outcome variables sought. Medilogic and Tekscan were most effective between 200 and 300kPa; Pedar performed well across all pressures. Contact area was less precise, but relatively repeatable for all systems.

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.

Effect of antipronation foot orthosis geometry on compression of heel and arch soft tissues

This study aimed to understand how systematic changes in arch height and two designs of heel wedging affect soft tissues under the foot. Soft tissue thickness under the heel and navicular was measured using ultrasound. Heel pad thickness was measured when subjects were standing on a flat surface and standing on an orthosis with 4 and 8 degree extrinsic wedges and 4 mm and 8 mm intrinsic wedges (n = 27). Arch soft tissue thickness was measured when subjects were standing and when standing on an orthosis with -6 mm, standard, and +6 mm increments in arch height (n = 25). Extrinsic and intrinsic heel wedges significantly increased soft tissue thickness under the heel compared with no orthosis. The 4 and 8 degree extrinsic wedges increased tissue thickness by 28% and 27.6%, respectively, while the 4 mm and 8 mm intrinsic wedges increased thickness by 23% and 14.6%, respectively. Orthotic arch height significantly affected arch soft tissue thickness. Compared with the no orthosis condition, the -6 mm, standard, and +6 mm arch heights decreased arch tissue thickness by 9%, 10%, and 11.8%, respectively. This study demonstrates that change in orthotic geometry creates different plantar soft tissue responses that we expect to affect transmission of force to underlying foot bones.

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.

An investigation into plantar pressure measurement protocols for footwear research

Many researchers investigate how footwear design affects plantar pressure (PP) and ask participants to walk in unfamiliar footwear as part of their studies. However, there are no clear guidelines for the required period of time or number of steps a healthy participant requires to acclimatise to unfamiliar footwear. Nor are there clear guidelines for how many steps should be collected to produce data that is representative of gait in each particular shoe being tested. There were therefore two aims to this study: (1) to investigate the number of steps required to produce an average step that is representative of normal gait; (2) to investigate the number of steps required for a participant to acclimatise to a range of footwear types. PP data were collected in 20 healthy participants whilst they walked for 400 m in a range of footwear. The results showed that the number of steps required for both acclimatisation and to ensure data quality are dependent on shoe type and the foot region being investigated. It is recommended that 30 steps from one foot are collected during data collection and an acclimatisation period of at least 166 steps is given for each shoe condition. The former recommendation is not met by most studies in the literature.

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.