Structural and functional predictors of regional peak pressures under the foot during walking

Plantar pressures in people with midfoot osteoarthritis: cross-sectional findings from the Clinical Assessment Study of the Foot

BACKGROUND

Midfoot osteoarthritis (OA) is a common condition, however its aetiology is not well understood. Understanding how plantar pressures differ between people with and without midfoot OA may provide insight into the aetiology and how best to manage this condition.

RESEARCH QUESTION

To compare plantar pressures between people with and without symptomatic radiographic midfoot OA.

METHODS

This was a cross-sectional study of adults aged ≥ 50 years registered with four UK general practices who reported foot pain in the past year. Symptomatic radiographic midfoot OA was defined as midfoot pain in the last four weeks, combined with radiographic OA in one or more midfoot joints. Cases were matched 1:1 for sex and age ( ± 5 years) to controls. Peak plantar pressure and maximum force in 10 regions of the foot were determined using a pressure platform (RSscan International, Olen, Belgium) and compared between the groups using independent samples t-tests and effect sizes (Cohen's d).

RESULTS

We included 61 midfoot OA cases (mean age 67.0, SD 8.1, 31 males, 30 females) and matched these to 61 controls (mean age 66.0, SD 7.9). Midfoot OA cases displayed greater force (d=0.79, medium effect size, p = <0.001) and pressure at the midfoot (d=0.70, medium effect size, p = <0.001), greater force at the fourth metatarsophalangeal (MTP) joint (d=0.28, small effect size, p = 0.13), and fifth MTP joint (d=0.37, small effect size, p = 0.10) and greater pressure at the fifth MTP joint (d=0.34, small effect size, p = 0.13). They also displayed lower force (d=0.40, small effect size, p = 0.02) and pressure at the hallux (d=0.50, medium effect size, p = <0.001) and lower force (d=0.54, medium effect size, p = <0.001) and pressure at the lesser toes (d=0.48, small effect size, p = <0.001) compared with controls.

SIGNIFICANCE

Midfoot OA appears to be associated with lowering of the medial longitudinal arch, greater lateral push off and less propulsion at toe off. Longitudinal studies are needed to establish causal relationships.

Spatiotemporal Evolution of Toddlers' Regional Foot Pressure Distribution and Center of Pressure at Antero-Posterior Axis During Learning of Standing

We investigated quiet stance of newly standing toddlers every three months (trimesters) of their second year of life. Their anteroposterior center-of-pressure (CoPx) velocity and centroidal frequency (CFREQ: 2.36 ± 0.10 to 1.50 ± 0.11 Hz) decreased over time. Besides, mean pressures revealed a potential role-sharing of foot regions in learning and control aspects of standing, with hindfoot carrying the highest (23.89 ± 6.47 kPa) pressure while forefoot the lowest (10.26 ± 2.51 kPa). The highest CFREQ of pressure signal was at midfoot. Through regional CoPx, forefoot has manifested the highest CFREQ (2.10 ± 0.40 Hz) and 90% power frequency (90%PF), whereas hindfoot presented the lowest (CFREQ: 1.80 ± 0.33 Hz). CFREQ and 90%PF of pressure and regional CoPx significantly decreased throughout the trimesters.

Age, Gender, Body Mass Index, and Foot Loading During Gait

Background

The aim was to analyze changes in normal functional parameters of gait analysis by aging, sex, and body mass index (BMI).

Methods

A cross-sectional study with a consecutive sample of asymptomatic subjects was performed between 2014 and 2020. Primary outcomes were time and force parameters (contact time and center of force [CoF] time), in the heel, midfoot, and metatarsal areas, measured using an in-office force platform.

Results

A total of 156 subjects (312 feet) were included, including 67% of women with a mean age of 47 years. The mean of total contact time was similar in males and females (P = .695) and across BMI (P = .413). Contact time did not show differences by region (P = .648 heel, P = .286 midfoot, and P = .690 metatarsal). CoF time in the heel and metatarsal areas did not change between males and females (P = .288 and P = .879, respectively); meanwhile, it was different in midfoot (P = .002). Maximum force showed a reduction between sexes in the heel (P = .039) but did not in the midfoot and metatarsal areas. By age, differences were detected in the heel and metatarsal areas in females (P = .002 and P = .001) and the metatarsal area in males (P = .001). According to the age groups, total contact time increased in females (P = .001) but not in males (P = .018), and no differences were detected between foot areas. In females, CoF time did not change either foot areas or age groups. In males, CoF time values increased in the midfoot area in the older group (P = .001).

Conclusion

Time variables did not change by foot region, independent of age, sex, and BMI. Heel maximum force decreased in females, probably linked to adaptive phenomena by aging. The midfoot remains stable, and acts as an undamaged "bridge." These parameters could be interpreted as normal in asymptomatic subjects.

Level of Evidence

Level III, diagnostic and prognostic.

Body mass index and maximum available midfoot motion are associated with midfoot angle at peak heel rise in people with type 2 diabetes mellitus and peripheral neuropathy

PURPOSE

Midfoot movement dysfunction, as measured by heel rise performance, is associated with midfoot deformity in people with diabetes and peripheral neuropathy. Understanding contributors of midfoot movement dysfunction may help clinicians understand deformity progression. The purpose of this study was to determine the factors associated with midfoot angle at peak heel rise.

METHODS

The outcomes of fifty-eight participants with type 2 diabetes mellitus and peripheral neuropathy were analyzed. Midfoot (forefoot on hindfoot) sagittal kinematics during unilateral heel rise task were measured using 3-dimensional motion analysis. A multivariate linear regression model was used to predict midfoot sagittal movements at peak heel rise. Independent variables that were entered in the model were (in order of entry): age, body mass index, intrinsic foot muscle volume, and maximum available midfoot plantarflexion range of motion. Intrinsic foot muscle volume was obtained from magnetic resonance imaging and maximum available midfoot motion was measured during non-weightbearing plantarflexion using 3-dimensional motion analysis.

RESULTS

Body mass index (R² = 30.5%, p < 0.001) and maximum available midfoot plantarflexion range of motion (R² = 10.9%, p = 0.001) were significant factors that accounted for 41.4% of variance of midfoot angle at peak heel rise, while age and intrinsic foot muscle volume were not significant predictors.

CONCLUSIONS

Greater body mass index and less available midfoot plantarflexion range of motion were associated with greater midfoot movement dysfunction. These two significant predictors are potentially modifiable, suggesting possible improvements in midfoot movements with reduction in body weight and increasing midfoot plantarflexion range of motion. Health care professionals should consider patient's weight and joint motion when prescribing foot exercise(s) to prevent excessive midfoot collapse during weightbearing tasks.

Investigation of Impact of Walking Speed on Forces Acting on a Foot-Ground Unit

Static and dynamic methods can be used to assess the way a foot is loaded. The research question is how the pressure on the feet would vary depending on walking/running speed. This study involved 20 healthy volunteers. Dynamic measurement of foot pressure was performed using the Ortopiezometr at normal, slow, and fast paces of walking. Obtained data underwent analysis in a “Steps” program. Based on the median, the power generated by the sensors during the entire stride period is the highest during a fast walk, whereas based on the average; a walk or slow walk prevails. During a fast walk, the difference between the mean and the median of the stride period is the smallest. Regardless of the pace of gait, the energy released per unit time does not depend on the paces of the volunteers’ gaits. Conclusions: Ortopiezometr is a feasible tool for the dynamic measurement of foot pressure. For investigations on walking motions, the plantar pressure analysis system, which uses the power generated on sensors installed in the insoles of shoes, is an alternative to force or energy measurements. Regardless of the pace of the walk, the amounts of pressure applied to the foot during step are similar among healthy volunteers.

Three-Dimensional Innate Mobility of the Human Foot on Coronally-Wedged Surfaces Using a Biplane X-Ray Fluoroscopy

Improving our understanding on how the foot and ankle joints kinematically adapt to coronally wedged surfaces is important for clarifying the pathogenetic mechanism and possible interventions for the treatment and prevention of foot and lower leg injuries. It is also crucial to interpret the basic biomechanics and functions of the human foot that evolved as an adaptation to obligatory bipedal locomotion. Therefore, we investigated the three-dimensional (3D) bone kinematics of human cadaver feet on level (0°, LS), medially wedged (−10°, MWS), and laterally wedged (+10°, LWS) surfaces under axial loading using a biplanar X-ray fluoroscopy system. Five healthy cadaver feet were axially loaded up to 60 kg (588N) and biplanar fluoroscopic images of the foot and ankle were acquired during axial loading. For the 3D visualization and quantification of detailed foot bony movements, a model-based registration method was employed. The results indicated that the human foot was more largely deformed from the natural posture when the foot was placed on the MWS than on the LWS. During the process of human evolution, the human foot may have retained the ability to more flexibly invert as in African apes to better conform to MWS, possibly because this ability was more adaptive even for terrestrial locomotion on uneven terrains. Moreover, the talus and tibia were externally rotated when the foot was placed on the MWS due to the inversion of the calcaneus, and they were internally rotated when the foot was placed on the LWS due to the eversion of the calcaneus, owing to the structurally embedded mobility of the human talocalcaneal joint. Deformation of the foot during axial loading was relatively smaller on the MWS due to restricted eversion of the calcaneus. The present study provided new insights about kinematic adaptation of the human foot to coronally wedged surfaces that is inherently embedded and prescribed in its anatomical structure. Such detailed descriptions may increase our understanding of the pathogenetic mechanism and possible interventions for the treatment and prevention of foot and lower leg injuries, as well as the evolution of the human foot.

Clinical foot measurements as a proxy for plantar pressure testing in people with diabetes

Background

High plantar pressures are associated with increased foot ulcer risk in people with diabetes. Identification of high plantar pressures in people with diabetes is clinically challenging due to time and cost constraints of plantar pressure testing. Factors affecting foot biomechanics, including reduced joint range of motion and foot deformity, are implicated in the development of high plantar pressures and may provide a method to clinically identify those at risk of pressure related complications. The aim of this study was to investigate the contribution of joint range of motion and foot deformity measures on plantar pressures in a community dwelling group with diabetes.

Methods

Barefoot (Tekscan HR Mat™) and in-shoe (Novel Pedar-X®) plantar pressure variables, weight bearing ankle dorsiflexion, hallux range of motion, lesser toe deformities and hallux abductus (HAV) scale were assessed in 136 adults with diabetes (52.2% male; mean age 68.4 years). Multivariate multiple linear regression was used to assess the effect of the four biomechanical factors plus neuropathy and body mass index on plantar pressure variables. Non-parametric bootstrapping was employed to determine the difference in plantar pressure variables for participants with two or more foot biomechanical pathologies compared to those with less than two pathologies.

Results

Almost one third (32%) of the cohort had two or more foot biomechanical pathologies. Participants with two or more foot biomechanical pathologies displayed significant increases in all barefoot plantar pressure regions (except forefoot), compared to those with less than two pathologies. No significant changes were found for the in-shoe plantar pressure variables. The regression model explains between 9.9% (95%CI: 8.4 to 11.4%) and 29.6% (95% CI: 28.2 to 31%), and between 2.5% (1.0 to 4.0%) and 43.8% (95% CI: 42.5–44.9%), of the variance in the barefoot and in-shoe plantar pressure variables respectively.

Conclusions

Participants presenting with two or more factors affecting foot biomechanics displayed higher peak pressures and pressure time integrals in all foot regions compared to those with less than two factors. The tests used in this study could help clinicians detect elevated plantar pressures in people with diabetes and present an opportunity for early preventative interventions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13047-021-00494-4.

Plantar Pressure Distribution Among Diabetes and Healthy Participants: A Cross-sectional Study

Background:

Plantar Pressure distribution refers to the distribution of force over the sole of the foot. Recently many studies indicate plantar pressure distribution assisted in determining and managing the impairment related to musculoskeletal disorders.

Methods:

This cross-sectional study was conducted with forty participants (20 diabetes type 2 patients +20 healthy) from Imam Abdulrahman bin Faisal University. All the measurements were taken in the morning session. To measure height and weight, participants took off their shoes and stood on the stadiometer. The body mass index determined with the help of a bioelectric impedance device to get the health level of the participants—Proclaimed diabetes type 2 patients selected for the data collection. Tekscan's Mobile Mat was used to determine the plantar pressure of healthy and diabetes participants.

Results:

The finding revealed that diabetes participants have more pressure in the mid-foot section, whereas healthy participants showed more pressure on the heel section. The metatarsal section showed similar types of pressure distribution in both participants. The result also revealed that diabetes participants have more peak pressures, time integral, and gradient than healthy participants. Significant differences between diabetes and healthy participants were existing.

Conclusions:

The findings highlight the importance of measuring plantar pressure distribution since these are known to incorporate in the main parts of the foot and thus provide a shred of constructive evidence for the total load exposer of a single leg static task.

Reliability of ultrasound in evaluating the plantar skin and fat pad of the foot in the setting of diabetes

Ultrasound can be used to assess injury and structural changes to the soft-tissue structure of the foot. It may be useful to assess the feet of people with diabetes who are at increased risk of plantar soft-tissue pathological changes. The aim of this study was to determine if ultrasound measurements of plantar soft-tissue thickness and assessments of tissue acoustic characteristics are reliable in people with and without diabetes mellitus. A repeated measures design was used to determine intra-observer reliability for ultrasound measurements of plantar skin and fat pad thickness and intra- and inter-observer reliability of plantar skin and fat pad tissue characterisation assessments made at foot sites which are at risk of tissue injury in people with diabetes. Thickness measurements and tissue characterisation assessments were obtained at the heel and forefoot in both the unloaded and compressed states and included discrete layers of the plantar tissues: skin, microchamber, horizontal fibrous band, macrochamber and total soft-tissue depth. At each site, relative intra-observer reliability was achieved for the measurement of at least one plantar tissue layer. The total soft-tissue thickness measured in the unloaded state (ICC 0.925-0.976) demonstrated intra-observer reliability and is the most sensitive for detecting small change on repeated measures. Intra-observer agreement was demonstrated for tissue characteristic assessments of the skin at the heel (k = 0.70), fat pad at the lateral sesamoid region (k = 0.70) and both skin and fat pad at the second (k = 0.80, k = 0.70 respectively) and third metatarsal heads (k = 0.90, k = 0.79 respectively). However, acceptable inter-observer agreement was not demonstrated for any tissue characteristic assessment, therefore the use of multiple observers should be avoided when making these assessments.

Simple model of arch support: Relevance to Charcot Neuroarthropathy

BACKGROUND

Charcot neuropathy is a common complication resulting from poorly controlled diabetes and peripheral neuropathy leading to the collapse, and ultimately the breakdown, of the midfoot. Mechanically, it is likely that a compromised arch support in this, or any other patient group that experiences foot flattening, would be associated with slippage at the distal and proximal interface regions of the plantar surface of the foot and the adjacent support surface. This slippage, although difficult to quantify with standard motion capture systems used in a gait laboratory, could potentially be assessed with systems for monitoring interface shear stresses. However, before investing in such systems, a correlation between arch flattening and interface shear stresses needs to be verified.

METHODS

For this purpose, a sagittal plane model of a foot was developed using a multi-body dynamics package (MSC Adams). This model mimicked a subject swaying back and forth, and was constructed to show the dependence of interface stresses on altered arch support.

FINDINGS

The model's predictions matched typical FootSTEPS data: lengthening of the arch of 1-2 mm, sway oscillations of 0.22-0.33 s and frictional force differences (calcaneus relative to forefoot) of 60 N. Of clinical relevance, when the stiffness of the plantar spring (representing aponeurosis and intrinsic muscles) was reduced by 10%, the frictional force difference increased by about 6.5%.

INTERPRETATION

The clinical implications of this study are that, while arch lengthening of less than 2 mm might be difficult to measure reliably in a gait lab, using shear sensors under the forefoot and hindfoot should allow arch support to be assessed in a repeatable manner.

Using Manchester Scale classification of Hallux Valgus as a valuable tool in determining appropriate risk categorization during initial diabetic foot screening in primary health care settings

Limitations have been identified in the current state of primary care practises with regards to identifying and correctly categorizing foot deformity and its associated risk of developing foot ulcers in patients with diabetes. This study aims to bridge these gaps through the implementation of additional categorization tools to be made available for primary care professionals. This study thus analysed the relationship between foot pressure distribution and amount in patients with diabetes with Hallux Valgus foot deformity, and its different stages, in order to better understand the clinical applications of the Manchester Scale. Statistically significant data in pressure distribution (P < 0.05) was found in all three severity groups identified by the Manchester Scale (Mild, Moderate and Severe) when compared to a No deformity group. However, only the Severe Hallux Valgus group crossed the threshold over 500 kPa in the area of first metatarsal bone. Further research should aim to analyse pressure distribution and amount in patients with both diabetes and diabetic neuropathy of all stages of Hallux Valgus.

Health View to Decrease Negative Effect of High Heels Wearing: A Systemic Review

Effective recommendations about how to decrease adverse effects of high heels (HH) need to be provided, since wearing HH is inevitable for most women in their daily life, regardless of their negative impacts on the foot morphology. The main purpose of this systematic review was to summarize studies which have provided specific information about how to effectively offset the negative effects of wearing HH, in the case of women, by means of examining heel height, insole, and heel base support (HBS). Some evidence indicate the following: (i) the range of appropriate heel height for HH shoes is 3.76 cm to 4.47 cm; (ii) compared to small HBS, the larger ones effectively increase gait stability, reduce risk of ankle injury, and improve comfort rating during HH walking; and (iii) the use of a total contact insert (TCI) significantly decreases plantar pressure and the impact on the foot, resulting in higher perceived comfort. It must be noted that these results are based on short-term research; therefore, any conclusions with regard to effects in the long term should be taken with a grain of salt. Nevertheless, future studies should be aimed at combining numerical and experimental methods, in order to provide personal recommendations for HH shoes by considering heel height and HBS size, based on the individual characters (weight, height, and age).

Reliability of centre of pressure, plantar pressure, and plantar-flexion isometric strength measures: A systematic review

BACKGROUND

Centre of pressure (COP), plantar pressure (PP), and plantar-flexion isometric strength (PF_isom) are often examined in relation to postural control and gait.

RESEARCH QUESTION

Our aim was to systematically review and quality appraise articles addressing the reliability of COP and PP measures in static stance and PF_isom measures.

METHODS

Three electronic databases (SCOPUS®, SportDISCUS™, and PubMed) were searched and supplemented by a manual search. Peer-reviewed original research on the reliability of COP, PP, and PF_isom in healthy adults (≥18 years) was included. Quality appraisal was done according to the updated COnsensus-based Standards for the selection of health Measurement INstruments reliability checklist. Data regarding study characteristics, test protocols, outcome measures, and reliability metrics were extracted.

RESULTS

Forty articles met inclusion and were assessed for their methodological quality. Only four articles (10%) obtained uppermost quality scores. From the reviewed studies, the most reliable measures were: COP sway area and path length; PP mean pressure, percentage body weight distribution, and contact area; and PF_isom peak torque and force. Although these measures generally exhibited good-to-excellent relative reliability based on correlation coefficients, absolute reliability based on typical errors were not always optimal (variation > 10%). Literature on PP reliability was scarce (n = 2).

SIGNIFICANCE

Our findings highlight the need for better quality methodological reliability studies to be undertaken to make stronger inferences about the reliability of COP, PP, and PF_isom measures. The most reliable measures based on the current review are: COP sway area and path length; PP mean pressure, percentage of body weight distribution, and contact area; and PF_isom peak torque and peak force. These measures are the ones that should be selected preferentially in clinical settings, bearing in mind that their typical errors might be suboptimal despite exhibiting strong relative reliability.

Understanding the foot's functional anatomy in physiological and pathological conditions: the calcaneopedal unit concept

BACKGROUND

A thorough review of the available orthopaedic literature shows significant controversies, inconsistencies and sparse data regarding the terminology used to describe foot deformities. This lack of consensus on terminology creates confusion in professional discussions of foot anatomy, pathoanatomy and treatment of deformities. The controversies apply to joint movements as well as static relationships between the bones.

DESCRIPTION

The calcaneopedal unit (CPU) is a specific anatomical and physiological entity, represented by the entire foot excepted the talus. The calcaneus, midfoot and forefoot are solidly bound by three strong ligaments that create a unit that articulates with the talus. The movement of the CPU is complex, as it rotates under the talus, around the axis of Henke that coincides with the talo-calcaneal ligament of Farabeuf.This calcaneopedal unit is deformable. It is compared with a twisted plate, able to adapt to many physiological situations in standing position, in order to acheive a plantigrade position.Moreover, the calcaneopedal unit and the talo-tibiofibular complex are interdependent; rotation of the latter produces morphologic modifications inside the former and vice versa.

PURPOSE

This paper is a review article of this concept and of its physiopathological applications.

Association of quadriceps angle with plantar pressure distribution, navicular height and calcaneo-tibial angle

OBJECTIVE

The aim of study was to analyze the association between Quadriceps Angle (QA) and plantar pressure, navicular height (NH), and calcaneo-tibial angle (CTA).

METHODS

A total of 64 volunteers (mean age: 22.25 ± 2.54 (range:19-33)) participated in this cross sectional study. EMED-m (Novel GmbH, Germany) electronic pedobarograph was employed for dynamic plantar pressure measurement using two step protocol. The angle between the vertical axis of calcaneus and the long axis of Achilles tendon for CTA. The height of navicular tubercle from the ground was measured while the subject was standing on both feet for NH. QA was measured while the subject was standing in a relaxed posture where both feet bearing equal weight.

RESULTS

There were significant negative correlations between QA and maximum force (MxF) under the 4th. metatarsal head (MH4). The QA was also significantly correlated with MxF and force-time integral (FTI) under the bigtoe (BT). FTI under the 3rd. metatarsal head (MH3), MH4 and 5th. metatarsal head (MH5) were significantly negatively correlated with QA. Pressure-time integral (PTI) under the MH4 and MH5 were found to be significantly negatively correlated with QA. A significant correlation was also found between QA and NH (p < 0.0001), whilst there was no correlation between QA and CTA. Regression analysis showed that NH was appeared as the major contributor for the QA (β = -0.49, p < 0.001) in the dynamic condition, followed by BT-FTI (β = 0.37, p < 0.001) and MH5-MxF (β = -0.21, p < 0.037).

CONCLUSION

These findings may imply that the NH which can at least be controlled by appropriate shoe inserts may affect QA. This way, loading pattern of both plantar region and whole lower extremity may be altered.

LEVEL OF EVIDENCE

Level III, Diagnostic Study.

Physical Rehabilitation in Leprosy

Physical Rehabilitation in Leprosy

The relationship between foot posture and plantar pressure during walking in adults: A systematic review

BACKGROUND

Foot posture is a risk factor for some lower limb injuries, however the underlying mechanism is not well understood. Plantar pressure analysis is one technique to investigate the interaction between foot posture and biomechanical function of the lower limb.

RESEARCH QUESTION

The aim of this review was to investigate the relationship between foot posture and plantar pressure during walking.

METHODS

A systematic database search was conducted using MEDLINE, CINAHL, SPORTDiscus and Embase to identify studies that have assessed the relationship between foot posture and plantar pressure during walking. Included studies were assessed for methodological quality. Meta-analysis was not conducted due to heterogeneity between studies. Inconsistencies included foot posture classification techniques, gait analysis protocols, selection of plantar pressure parameters and statistical analysis approaches.

RESULTS

Of the 4213 citations identified for title and abstract review, sixteen studies were included and underwent quality assessment; all were of moderate methodological quality. There was some evidence that planus feet display higher peak pressure, pressure-time integral, maximum force, force-time integral and contact area predominantly in the medial arch, central forefoot and hallux, while these variables are lower in the lateral and medial forefoot. In contrast, cavus feet display higher peak pressure and pressure-time integral in the heel and lateral forefoot, while pressure-time integral, maximum force, force-time integral and contact area are lower for the midfoot and hallux. Centre of pressure was more laterally deviated in cavus feet and more medially deviated in planus feet. Overall, effect sizes were moderate, but regression models could only explain a small amount of variance in plantar pressure variables.

SIGNIFICANCE

Despite these significant findings, future research would benefit from greater methodological rigour, particularly in relation to the use of valid foot posture measurement techniques, gait analysis protocols, and standardised approaches for analysis and reporting of plantar pressure variables.

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.

POFBG-Embedded Cork Insole for Plantar Pressure Monitoring

We propose a novel polymer optical fiber (POF) sensing system based on fiber Bragg gratings (FBGs) to measure foot plantar pressure. The plantar pressure signals are detected by five FBGs, in the same piece of cyclic transparent optical polymer (CYTOP) fiber, which are embedded in a cork insole for the dynamic monitoring of gait. The calibration and measurements performed with the suggested system are presented, and the results obtained demonstrate the accuracy and reliability of the sensing platform to monitor the foot plantar pressure distribution during gait motion and the application of pressure. This architecture does not compromise the patient's mobility nor interfere in their daily activities. The results using the CYTOP fiber showed a very good response when compared with solutions using silica optical fibers, resulting in a sensitivity almost twice as high, with excellent repeatability and ease of handling. The advantages of POF (e.g., high flexibility and robustness) proved that this is a viable solution for this type of application, since POF's high fracture toughness enables its application in monitoring patients with higher body mass compared with similar systems based on silica fiber. This study has demonstrated the viability of the proposed system based on POF technology as a useful alternative for plantar pressure detection systems.

Plantar pressure differences between cases with symptoms of clinically diagnosed chronic exertional compartment syndrome and asymptomatic controls

BACKGROUND

Anterior chronic exertional compartment syndrome of the leg has been hypothesised to develop due to excessive muscle activity and foot pronation. Plantar pressure variables related to lower limb muscle activity and foot type may therefore provide insight into this condition.

METHODS

70 male cases and 70 asymptomatic controls participated. A clinical diagnosis was established from typical symptoms, with clinical examination excluding other pathologies. Plantar pressure variables during walking, hypothesised to be related to foot type, toe extensor activity or had shown predictive validity for general exercise-related lower leg pain, were extracted.

FINDINGS

Cases were shorter in height (mean difference 2.4cm), had greater body mass (mean difference 4.4kg) and had reduced ankle dorsiflexion range of motion than controls (mean difference 1.5cm). Plantar pressure variables indicative of foot-type and toe extensor activity did not differ between groups (P>0.05). The magnitude of medial forefoot loading was the strongest plantar pressure predictor of the presence of chronic exertional compartment syndrome (Odds ratio:0.87, P=0.005). There was also some evidence of greater lateral heel loading at 5% of stance time (P=0.049-0.054).

INTERPRETATION

The lack of association with foottype-related and toe extensor activity-related plantar pressure variables suggest that these are not risk factors for the development of chronic exertional compartment syndrome, contrary to earlier hypotheses. The greater lateral to medial loading could theoretically represent increased Tibialis anterior muscle activity at heel strike but a subsequent loss of control as the ankle is lowered. Future studies directly investigating muscle activity and function are now required.

An Imaged-Based Three-Dimensional Study of First Metatarsal Protrusion Distance in Women with and Without Hallux Valgus

BACKGROUND

First metatarsal protrusion distance (MPD) has been commonly studied as a characteristic of hallux valgus deformity. To date, the majority of investigations have used radiographic methods, with most reporting first metatarsal (ray) protrusion to be associated with deformity. As an alternative, this study used a three-dimensional (3-D) image acquisition and data analysis method to quantify MPD.

METHODS

Magnetic resonance images were acquired in weightbearing on 29 women (19 with hallux valgus; 10 controls). After the 3-D images were reconstructed into virtual bone models, two examiners measured MPD in relation to the navicular. In addition to a reliability analysis, a t test assessed for group differences in demographics, foot posture (hallux valgus, intermetatarsal angles), and MPD.

RESULTS

Group demographics were not different, while measures of hallux valgus and intermetatarsal angles were different ( P < 0.01) between groups. The measurement of MPD was highly reliable (ICC [Formula: see text] 0.99; SEM [Formula: see text] 0.78 mm). Metatarsal protrusion averaged approximately -2.0 mm in both groups. There was no statistical group difference ( P = 0.89) in MPD.

CONCLUSIONS

The reconstructed image datasets captured the 3-D spatial relationship of the anatomy. Measurements of MPD were reliable. The first ray measured 2 mm shorter than the second ray in both the hallux valgus and control groups. Though unexpected, this result may prompt future study of the pathokinematics associated with hallux valgus that include the quantification of metatarsal protrusion with 3-D methods, instead of relying solely on single-plane radiograph reports.

In-vivo viscous properties of the heel pad by stress-relaxation experiment based on a spherical indentation

Identifying the viscous properties of the plantar soft tissue is crucial not only for understanding the dynamic interaction of the foot with the ground during locomotion, but also for development of improved footwear products and therapeutic footwear interventions. In the present study, the viscous and hyperelastic material properties of the plantar soft tissue were experimentally identified using a spherical indentation test and an analytical contact model of the spherical indentation test. Force-relaxation curves of the heel pads were obtained from the indentation experiment. The curves were fit to the contact model incorporating a five-element Maxwell model to identify the viscous material parameters. The finite element method with the experimentally identified viscoelastic parameters could successfully reproduce the measured force-relaxation curves, indicating the material parameters were correctly estimated using the proposed method. Although there are some methodological limitations, the proposed framework to identify the viscous material properties may facilitate the development of subject-specific finite element modeling of the foot and other biological materials.

Does the lower extremity alignment affect the risk of falling?

Objectives

This study aims to investigate the effects of knee and foot alignments on the risk of falling.

Patients and methods

Between April 2016 and December 2016, a total of 74 individuals (24 males, 50 females; mean age 32.2±4.9 years; range 18 to 65 years) were included in the study. The knee Q angle and Chippaux-Smirak Index (CSI), Arch Index, and foot progression angle (FPA) evaluated by pedobarography were used for the assessment of the lower extremity alignment. The fall risk was evaluated by the Fall Index, Fourier 56 Index (F56), and Stability Index.

Results

The fall index was found to be correlated with the Q angle, CSI, the Arch index, and FPA (p<0.05). Q angle, Arch Index, and FPA which were explained 40% of the variance of the fall index. The Q angle was correlated with F56 and the stability index at the most position (p<0.05). The CSI was correlated with the F56 and the stability index at two and three positions, respectively (p<0.05); however, the Arch Index and FPA were not correlated with the F56 and Stability Index at any of the eight positions (p>0.05). According to the categorical regression analysis, the Q angle was the most effective on the F56 and Stability Index.

Conclusion

Our study results suggest that lower extremity malalignment increases the risk of falling. We believe that the risk of falling can be decreased by the reduction of these malalingments and, thus, mortality and morbidity associated with the fall can be reduced as well.

Spatiotemporal and plantar pressure patterns of 1000 healthy individuals aged 3-101 years

OBJECTIVE

The purpose of this study was to establish normative reference values for spatiotemporal and plantar pressure parameters, and to investigate the influence of demographic, anthropometric and physical characteristics.

METHODS

In 1000 healthy males and females aged 3-101 years, spatiotemporal and plantar pressure data were collected barefoot with the Zeno™ walkway and Emed^® platform. Correlograms were developed to visualise the relationships between widely reported spatiotemporal and pressure variables with demographic (age, gender), anthropometric (height, mass, waist circumference) and physical characteristics (ankle strength, ankle range of motion, vibration perception) in children aged 3-9 years, adolescents aged 10-19 years, adults aged 20-59 years and older adults aged over 60 years.

RESULTS

A comprehensive catalogue of 31 spatiotemporal and pressure variables were generated from 1000 healthy individuals. The key findings were that gait velocity was stable during adolescence and adulthood, while children and older adults walked at a comparable slower speed. Peak pressures increased during childhood to older adulthood. Children demonstrated highest peak pressures beneath the rearfoot whilst adolescents, adults and older adults demonstrated highest pressures at the forefoot. Main factors influencing spatiotemporal and pressure parameters were: increased age, height, body mass and waist circumference, as well as ankle dorsiflexion and plantarflexion strength.

CONCLUSION

This study has established whole of life normative reference values of widely used spatiotemporal and plantar pressure parameters, and revealed changes to be expected across the lifespan.

Three-dimensional innate mobility of the human foot bones under axial loading using biplane X-ray fluoroscopy

The anatomical design of the human foot is considered to facilitate generation of bipedal walking. However, how the morphology and structure of the human foot actually contribute to generation of bipedal walking remains unclear. In the present study, we investigated the three-dimensional kinematics of the foot bones under a weight-bearing condition using cadaver specimens, to characterize the innate mobility of the human foot inherently prescribed in its morphology and structure. Five cadaver feet were axially loaded up to 588 N (60 kgf), and radiographic images were captured using a biplane X-ray fluoroscopy system. The present study demonstrated that the talus is medioinferiorly translated and internally rotated as the calcaneus is everted owing to axial loading, causing internal rotation of the tibia and flattening of the medial longitudinal arch in the foot. Furthermore, as the talus is internally rotated, the talar head moves medially with respect to the navicular, inducing external rotation of the navicular and metatarsals. Under axial loading, the cuboid is everted simultaneously with the calcaneus owing to the osseous locking mechanism in the calcaneocuboid joint. Such detailed descriptions about the innate mobility of the human foot will contribute to clarifying functional adaptation and pathogenic mechanisms of the human foot.

Insole optical fiber Bragg grating sensors network for dynamic vertical force monitoring

In an era of unprecedented progress in technology and increase in population age, continuous and close monitoring of elder citizens and patients is becoming more of a necessity than a luxury. Contributing toward this field and enhancing the life quality of elder citizens and patients with disabilities, this work presents the design and implementation of a noninvasive platform and insole fiber Bragg grating sensors network to monitor the vertical ground reaction forces distribution induced in the foot plantar surface during gait and body center of mass displacements. The acquired measurements are a reliable indication of the accuracy and consistency of the proposed solution in monitoring and mapping the vertical forces active on the foot plantar sole, with a sensitivity up to 11.06 ?? pm / N . The acquired measurements can be used to infer the foot structure and health condition, in addition to anomalies related to spine function and other pathologies (e.g., related to diabetes); also its application in rehabilitation robotics field can dramatically reduce the computational burden of exoskeletons’ control strategy. The proposed technology has the advantages of optical fiber sensing (robustness, noninvasiveness, accuracy, and electromagnetic insensitivity) to surpass all drawbacks verified in traditionally used sensing systems (fragility, instability, and inconsistent feedback).

5th Congress of WUWHS Abstract book Florence, Italy September 25–29 2016

The abstract book contains the abstracts of keynote lectures, focus sessions, symposia, workshops, AIUC annual meeting, AISLEC annual meeting, EPUAP annual meeting, ETRS special session, sponsor symposia, oral presentations, poster presentations and the subject index.

An Investigation of Structure, Flexibility, and Function Variables that Discriminate Asymptomatic Foot Types

It has been suggested that foot type considers not only foot structure (high, normal, low arch), but also function (overpronation, normal, oversupination) and flexibility (reduced, normal, excessive). Therefore, this study used canonical regression analyses to assess which variables of foot structure, function, and flexibility can accurately discriminate between clinical foot type classifications. The feet of 61 asymptomatic, healthy adults (18–77 years) were classified as cavus (N = 24), rectus (N = 54), or planus (N = 44) using standard clinical measures. Custom jigs assessed foot structure and flexibility. Foot function was assessed using an emed-x plantar pressure measuring device. Canonical regression analyses were applied separately to extract essential structure, flexibility, and function variables. A third canonical regression analysis was performed on the extracted variables to identify a combined model. The initial combined model included 30 extracted variables; however 5 terminal variables (malleolar valgus index, arch height index while sitting, first metatarsophalangeal joint laxity while standing, pressure-time integral and maximum contact area of medial arch) were able to correctly predict 80.7% of foot types. These remaining variables focused on specific foot characteristics (hindfoot alignment, arch height, midfoot mechanics, Windlass mechanism) that could be essential to discriminating foot type.

Evaluation of Plantar Pressure Distribution in Relationship to Body Mass Index in Czech Women During Walking

BACKGROUND

Excessive body weight seems to be a risk factor for foot loading. We sought to investigate the effect of different body mass index (BMI) levels on plantar pressure distribution during walking.

METHODS

In total, 163 women aged 45 to 65 years (mean ± SD: age, 57.4 ± 5.3 years; BMI, 27.0 ± 5.3) participated in the study. The women were divided, on the basis of BMI, into a normal-weight, overweight, or obese group. The study used the four following plantar pressure parameters (PPPs): contact percentage, absolute pressure impulse, relative pressure impulse, and absolute peak pressure, which were recorded in ten foot regions using a pressure measurement system.

RESULTS

The normal-weight group, compared with the overweight and obese groups, had significantly lower absolute PPP values. In the hallux, second through fifth metatarsals, midfoot, and heel regions, we observed significant between-group differences in the two absolute PPPs (peak pressure and pressure impulse) (P < .001). Between-group differences in the relative PPPs were found in the fourth metatarsal, midfoot, and medial heel (relative impulse) and in the second metatarsal (contact percentage) (P < .001).

CONCLUSIONS

Higher BMI values correspond to a higher load on the foot during walking in women. The relative foot load in obese women is characterized by a pressure increase in the lateral forefoot and midfoot and by a pressure decrease in the medial heel.

The plantar calcaneal spur: a review of anatomy, histology, etiology and key associations

The plantar calcaneal spur (PCS) is a bony outgrowth from the calcaneal tuberosity and has been studied using various methods including cadavers, radiography, histology and surgery. However, there are currently a number of discrepancies in the literature regarding the anatomical relations, histological descriptions and clinical associations of PCS. Historically, authors have described the intrinsic muscles of the foot and/or the plantar fascia as attaching to the PCS. In this article we review the relationship between the PCS and surrounding soft tissues as well as examining the histology of the PCS. We identify a number of key associations with PCS, including age, weight, gender, arthritides, plantar fasciitis and foot position; these factors may function as risk factors in PCS formation. The etiology of these spurs is a contentious issue and it has been explained through a number of theories including the degenerative, inflammatory, traction, repetitive trauma, bone-formers and vertical compression theories. We review these and finish by looking clinically at the evidence that PCS causes heel pain.

Análise de confiabilidade de medidas das pressões plantares estática e dinâmica de crianças e adolescentes com desenvolvimento normal

RESUMO A pressão plantar é utilizada na avaliação clínica do pé e informa características da distribuição de carga plantar em atividades funcionais. Diversos instrumentos de avaliação podem ser utilizados e devem ter as propriedades psicométricas analisadas. A confiabilidade teste-reteste é uma medida de reprodutibilidade. O objetivo deste estudo foi analisar a confiabilidade teste-reteste das medidas de pressão máxima na estática e dinâmica de crianças e adolescentes com desenvolvimento normal (DN). Onze crianças e adolescentes com DN, de ambos os sexos, com idade entre 6 e 17 anos foram avaliados duas vezes, em uma plataforma sensível à pressão plantar em ortostatismo, com e sem calçado usual, com os pés posicionados de forma livre (passo interrompido) e com os pés alinhados. Dados dinâmicos foram obtidos pela caminhada sobre a plataforma com e sem calçado. Coeficientes de correlação intraclasse (CCI) foram analisados (α=0,05). Os CCI foram consistentes para: descarga de peso (DP) anterior calçado (CCI=0,83) e DP posterior descalço (CCI=0,95) e calçado (CCI=0,83) durante a análise estática com o passo interrompido. Também foram consistentes para a variável DP estática do membro inferior (MI) direito (CCI=0,86) e esquerdo (CCI=0,82) com passo interrompido descalço e, com os pés alinhados, utilizando calçados (CCI=0,82). Na análise do MI esquerdo, com o uso de calçado, a variável pressão máxima também gerou resultado satisfatório (CCI=0,85). As demais variáveis apresentaram variação de CCI entre 0,25 e 0,74, consideradas insatisfatórias. Conclui-se que os valores de CCI foram considerados excelentes para algumas condições estáticas e inconsistentes na avaliação dinâmica.

Effect on the parameters of the high-heel shoe and transfer time of ground reaction force during level walking

This study aimed to analyze an effect on the parameters of high-heel shoe and transfer time of ground reaction force during level walking and subjects participated were composed of adult female subjects (n=13) of 20s with height of high heel (0 cm, 9 cm, respectively). Instrument used for the study was 1 set force plate (AMTI-OR9-7) and sampling rate for data collection of analysis parameters was set-up at 1,000 Hz. The revelation of required coefficient of friction (RCOF) maximum showed significant difference with more rapid than that of 1st peak vertical force (1 PVF). Transfer time of body weight showed significant difference with more delay at 9 cm than that of 0 cm. RCOF required more frictional force required because PVF showed significant difference with larger value on 9 cm than that of 3 cm at 1 PVF. Both center of pressure (COP) x and COPy showed rather less displacement on 9 cm than that of 0 cm. In addition, level walking by high heel shoe did not control efficiently the ground reaction force due to restricted control capacity of coefficient of frictional force and therefore could suggest an inducement of muscle fatigue, heightening a possibility of sliding and falling due to decrease of frictional force.

Multiple linear regression approach for the analysis of the relationships between joints mobility and regional pressure-based parameters in the normal-arched foot

Plantar load can be considered as a measure of the foot ability to transmit forces at the foot/ground, or foot/footwear interface during ambulatory activities via the lower limb kinematic chain. While morphological and functional measures have been shown to be correlated with plantar load, no exhaustive data are currently available on the possible relationships between range of motion of foot joints and plantar load regional parameters. Joints' kinematics from a validated multi-segmental foot model were recorded together with plantar pressure parameters in 21 normal-arched healthy subjects during three barefoot walking trials. Plantar pressure maps were divided into six anatomically-based regions of interest associated to corresponding foot segments. A stepwise multiple regression analysis was performed to determine the relationships between pressure-based parameters, joints range of motion and normalized walking speed (speed/subject height). Sagittal- and frontal-plane joint motion were those most correlated to plantar load. Foot joints' range of motion and normalized walking speed explained between 6% and 43% of the model variance (adjusted R²) for pressure-based parameters. In general, those joints' presenting lower mobility during stance were associated to lower vertical force at forefoot and to larger mean and peak pressure at hindfoot and forefoot. Normalized walking speed was always positively correlated to mean and peak pressure at hindfoot and forefoot. While a large variance in plantar pressure data is still not accounted for by the present models, this study provides statistical corroboration of the close relationship between joint mobility and plantar pressure during stance in the normal healthy foot.

Effects of custom-made textile insoles on plantar pressure distribution and lower limb EMG activity during turning

Background

Turning during locomotion involves considerable changes of the body’s center of mass and reduced stability, as well as lower limb kinematics and kinetics. However, many previous studies have been carried out to evaluate the effectiveness and applications of orthotic insoles as well as different types of orthotic materials in various clinical symptoms, which are focused primarily on straight line walking. Hence, the influence of custom-made insoles with the use of advanced three-dimensional spacer fabrics on biomechanics parameters in terms of plantar pressure distribution and lower limb electromyography during turning movement was studied.

Methods

Twelve subjects performed 180-degree turning at a speed 3.07-3.74 km/h for five successful trials under 3 insoles conditions: wearing traditional ethylene vinyl acetate insoles and two different spacer-fabricated insoles, with the plantar pressure and lower limb muscle activity collected simultaneously. Turning movement was broken down into 3 phases for analysis: Turning initiation, turn around and turn termination.

Results

There was a statistically significance difference in plantar pressure between the traditional insoles and the insoles made of a spacer fabric as the top layer (p < 0.05). Compared to the traditional insoles, insoles made of a spacer fabric reduced the peak pressure (>12 %) and pressure–time integral (>13 %) in toes, metatarsal head 1 and metatarsal heads 2–3 at turning initiation; (>15 %) and (>17 %) in medial midfoot and medial heel at turn around. Insoles with spacer fabrics on the top and middle layer reduced both pressure parameters (>18 %) in toes and MTH 1 at turn termination. In terms of muscle activities, insoles with two-layer spacer fabrics could lower maximum muscle activities of vastus lateralis (>16 %; p < 0.05) at turn around.

Conclusions

Insoles with different fabrications could offer various pressure offloading patterns across the plantar and muscle activity changes while turning. Insoles with a spacer fabric on the top tend to reduce plantar pressure loading at different regions during turn initiation and turn around phases, while two-layer spacer-fabricated insoles may contribute to reduced vastus lateralis muscle activation during turn around. More importantly, this study provides a new dimension in the potential use of the textile-fabricated insoles which may widen the range of insole materials selection in the design and development of insoles so as to enhance the effectiveness of orthotic treatment.

Effects of mid-foot contact area ratio on lower body kinetics/kinematics in sagittal plane during stair descent in women

The mid-foot contact area relative to the total foot contact area can facilitate foot arch structure evaluation. A stair descent motion consistently provides initial fore-foot contact and utilizes the foot arch more actively for energy absorption. The purpose of this study was to compare ankle and knee joint angle, moment, and work in sagittal plane during stair descending between low and high Mid-Foot-Contact-Area (MFCA) ratio group. The twenty-two female subjects were tested and classified into two groups (high MFCA and low MFCA) using their static MFCA ratios. The ground reaction force (GRF) and kinematics of ankle and knee joints were measured while stair descending. During the period between initial contact and the first peak in vertical GRF (early absorption phase), ankle negative work for the low MFCA ratio group was 33% higher than that for the high MFCA ratio group (p<0.05). However, ankle negative work was not significantly different between the two groups during the period between initial contact and peak dorsiflexion angle (early absorption phase+late absorption phase). The peak ankle dorsiflexion angle was smaller in the low MFCA ratio group (p<0.05). Our results suggest that strategy of energy absorption at the ankle and foot differs depending upon foot arch types classified by MFCA. The low MFCA ratio group seemed to absorb more impact energy using strain in the planar fascia during early absorption phase, whereas the high MFCA ratio group absorbed more impact energy using increased dorsiflexion during late absorption phase.

Forefoot ulcer risk is associated with foot type in patients with diabetes and neuropathy

AIMS

To stratify the ulceration risk according to the foot morphology in people with diabetes and a history of forefoot neuropathic ulceration.

METHODS

A cross-sectional study was performed on 139 neuropathic individuals with diabetes and previous forefoot ulcers between January 2012 and February 2014. Foot position of the participants was evaluated by using the foot-posture index. A multivariate analysis adjusted for confounding variables was performed with the ulceration risk factors that were found in the univariate analysis.

RESULTS

Two hundred and fifty-eight feet were analysed, 104 (40.3%) feet had a history of ulceration on the forefoot and 154 (59.7%) feet had no previous ulceration. Two positive tests of neuropathy (p<0.001; CI[1.961-6.249] OR 3.500), presence of deformities (p=0.043; CI[1.020-3.599] OR 1.916) and foot type (p=0.039) showed an association with ulceration risk in multivariate analyses. Pronated feet showed a higher risk of ulceration than supinated feet (p=0.011; CI[1.253-5.708] OR 2.675), while significant differences between neutral and supinated feet were not found (p=0.221; CI[0.719-2.753] OR 1.476).

CONCLUSIONS

A pronated foot has a higher risk of ulceration on the forefoot in neuropathic people with deformities and diabetes mellitus. Foot type should be evaluated in people at risk of ulceration.

GAIT ANALYSIS DRIVEN 2D FINITE ELEMENT MODEL OF THE NEUROPATHIC HINDFOOT

The diabetic foot is one of the most serious complications of diabetes mellitus and it can lead to foot ulcerations and amputations. Finite element analysis quantifies the loads developed in the different anatomical structures and describes how these affect foot tissue during foot–floor interaction. This approach for the diabetic subjects’ foot could provide valuable information in the process of plantar orthosis fabrication and fit. The purpose of this study was to develop two finite element models of the hindfoot, of healthy and diabetic neuropathic subjects. These models accounts for in vivo kinematics, kinetics, plantar pressure (PP) data and magnetic resonance images. These were acquired during gait analysis on 10 diabetic neuropathics and 10 healthy subjects. Validity of the models has been assessed through comparison between the peak PPs of simulated and experimental data: root mean square error (RMSE) in percentage of the experimental peak value was evaluated. Two different finite elements analysis were performed: subject-specific simulations in terms of both geometry and gait analysis, and by adopting the complete gait analysis dataset as boundary conditions. Model predicted plantar pressures were in good agreement with those experimentally measured. Best agreement was obtained in the subject-specific case (RMSE of 13%).

Analysis of the Plantar Pressure Characteristics of Action Flying Kick for Martial Arts Athletes

Martial arts as the quintessence of the Chinese nation, after a thousand years of forging, its contents are rich and varied, the performance of a variety of forms, the value of its potential is enormous. This paper, regarding the action flying kick the as a starting point in competitive of martial arts, analysis the plantar pressure characteristics of action flying kick for martial arts athletes, and provided some quantization theory for the flying feet of jumping movements, give some suggestions in the process to jumping which may be injured. Firstly, this paper discussed the methods and steps for the analysis of the plantar pressure characteristics of action flying kick for martial arts athletes, summing up the process of the plantar pressure analysis and the experimental process. Then, the paper given six Jilin province martial arts athletes flying kick foot jump for bottom pressure test of the experimental results, and analyzed the experimental data in detail. By analyzing the experimental results, it can reveal regular pattern of the diversification of plantar pressure, so as to provide reference data for improving the effect of training and preventing injuries.

Effect of gait on formation of thermal environment inside footwear

In this study, the relationship between the gait condition and foot temperature distributions inside footwear was investigated using subject experiments. Mechanical, physical, and physiological variables such as the foot contact force, landing speed, and metabolic heat generation were also measured. Gait motion measurements showed that a large contact force was concentrated in the small area of the heel at the initial contact and later at the forefoot. A faster gait produced a larger contact force, higher landing velocity, higher skin temperature, and larger metabolism during gait. The temperature at the bottom of the foot increased, and the temperature on the upper side decreased. The metabolic heat generation had a basic impact on the temperature profile, and skin temperatures tended to increase gradually. In addition, high-temperature-elevation regions such as the big toe and heel coincided with regions with high-contact loads, which suggested a relationship between the temperature elevation and contact load.

Predictors of barefoot plantar pressure during walking in patients with diabetes, peripheral neuropathy and a history of ulceration

Objective

Elevated dynamic plantar foot pressures significantly increase the risk of foot ulceration in diabetes mellitus. The aim was to determine which factors predict plantar pressures in a population of diabetic patients who are at high-risk of foot ulceration.

Methods

Patients with diabetes, peripheral neuropathy and a history of ulceration were eligible for inclusion in this cross sectional study. Demographic data, foot structure and function, and disease-related factors were recorded and used as potential predictor variables in the analyses. Barefoot peak pressures during walking were calculated for the heel, midfoot, forefoot, lesser toes, and hallux regions. Potential predictors were investigated using multivariate linear regression analyses. 167 participants with mean age of 63 years contributed 329 feet to the analyses.

Results

The regression models were able to predict between 6% (heel) and 41% (midfoot) of the variation in peak plantar pressures. The largest contributing factor in the heel model was glycosylated haemoglobin concentration, in the midfoot Charcot deformity, in the forefoot prominent metatarsal heads, in the lesser toes hammer toe deformity and in the hallux previous ulceration. Variables with local effects (e.g. foot deformity) were stronger predictors of plantar pressure than global features (e.g. body mass, age, gender, or diabetes duration).

Conclusion

The presence of local deformity was the largest contributing factor to barefoot dynamic plantar pressure in high-risk diabetic patients and should therefore be adequately managed to reduce plantar pressure and ulcer risk. However, a significant amount of variance is unexplained by the models, which advocates the quantitative measurement of plantar pressures in the clinical risk assessment of the patient.

Plantar heel pain and foot loading during normal walking

Plantar heel pain is aggravated by weight-bearing, yet limited evidence exists regarding how people with heel pain load their feet during walking. Knowledge of loading patterns in people with plantar heel pain would enhance the understanding of their foot function and assist in developing intervention strategies. Plantar pressure using the Emed-AT platform (Novel Gmbh, Germany) was collected from 198 people with plantar heel pain and 70 asymptomatic controls during normal walking. Maximum force, force-time integral, peak pressure, pressure-time integral and contact time were measured in four quadrants of the heel, the midfoot and the medial and lateral forefoot. The symptomatic group was sub-divided into equal low-pain and high-pain groups using the Foot Health Status Questionnaire pain score. Following age and body mass comparison, multivariate analyses of covariance were performed to compare the heel pain group to the controls, and the low-pain group to the high-pain group, for each loading variable. The heel pain group displayed lower maximum force beneath the heel, lower peak pressure beneath the postero-lateral heel and lower maximum force beneath the medial forefoot. Force-time integrals were lower beneath the posterior heel regions and higher at the lateral forefoot. People with heel pain also had longer midfoot and forefoot contact time. Higher pain level was associated with lower peak pressure and maximum force beneath regions of the heel. Compared to the controls, people with plantar heel pain demonstrated reduced heel loading and modified forefoot loading consistent with a strategy to offload the painful heel.

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.

Fiber type composition of the human quadratus plantae muscle: a comparison of the lateral and medial heads

BACKGROUND

The human quadratus plantae muscle has been attributed a variety of functions, however no consensus has been reached on its significance to foot functioning. The architecture of the human quadratus plantae consists of an evolutionarily conserved lateral head, and a medial head thought to be unique to Man. Surveys of human anatomy have demonstrated the absence of either the medial or lateral head in 20% of the population, which may have implications for foot functioning if each muscle head performs a discrete function.

METHODS

We investigated the quadratus plantae from eleven formalin-embalmed specimens with a mean age of 84 ± 9 years. Immunohistochemical methods were used to determine the percentage of Type I and Type II muscle fibers in the medial and lateral heads of the quadratus plantae from these specimens.

RESULTS

Results showed striking homogeneity in fiber type composition within an individual, with an average difference in Type I fiber content of 4.1% between lateral and medial heads. Between individuals, however, the ratio of fiber types within the quadratus plantae was highly variable, with Type I fiber percentages ranging from 19.1% to 91.6% in the lateral head, and 20.4% to 97.0% within the medial head.

CONCLUSIONS

Our finding of similar fiber type composition of lateral and medial heads within an individual supports the hypothesis that the two heads have a singular function.

Plantar pressure as a risk assessment tool for diabetic foot ulceration in egyptian patients with diabetes

BACKGROUND

Diabetic foot ulceration is a preventable long-term complication of diabetes. In the present study, peak plantar pressures (PPP) and other characteristics were assessed in a group of 100 Egyptian patients with diabetes with or without neuropathy and foot ulcers. The aim was to study the relationship between plantar pressure (PP) and neuropathy with or without ulceration and trying to clarify the utility of pedobarography as an ulceration risk assessment tool in patients with diabetes.

SUBJECTS AND METHODS

A total of 100 patients having diabetes were selected. All patients had a comprehensive foot evaluation, including assessment for neuropathy using modified neuropathy disability score (MNDS), for peripheral vascular disease using ankle brachial index, and for dynamic foot pressures using the MAT system (Tekscan). The studied patients were grouped into: (1) diabetic control group (DC), which included 37 patients who had diabetes without neuropathy or ulceration and MNDS ≤2; (2) diabetic neuropathy group (DN), which included 33 patients who had diabetes with neuropathy and MNDS >2, without current or a history of ulceration; and (3) diabetic ulcer group (DU), which included 30 patients who had diabetes and current ulceration, seven of those patients also gave a history of ulceration.

RESULTS

PP parameters were significantly different between the studied groups, namely, forefoot peak plantar pressure (FFPPP), rearfoot peak plantar pressure (RFPPP), forefoot/rearfoot ratio (F/R), forefoot peak pressure gradient (FFPPG) rearfoot peak pressure gradient (RFPPG), and forefoot peak pressure gradient/rearfoot peak pressure gradient (FFPPG/RFPPG) (P < 0.05). FFPPP and F/R were significantly higher in the DU group compared to the DN and DC groups (P < 0.05), with no significant difference between DN and DC. FFPPG was significantly higher in the DU and DN groups compared to the DC group (P < 0.05). RFPPP and FFPPG/RFPPG were significantly higher in the DU and DN groups compared to the DC group (P < 0.05) with no significant difference between the DN and DU groups (P > 0.05). FFPPP, F/R ratio, FFPPG, and FFPPG/RFPPG correlated significantly with the severity of neuropathy according to MNDS (P < 0.05). These same variables as well as MNDS were also significantly higher in patients with foot deformity compared to those without deformity (P < 0.05). Using the receiver operating characteristic analysis, the optimal cut-point of PPP for ulceration risk, as determined by a balance of sensitivity, specificity, and accuracy was 335 kPa and was found at the forefoot. Multivariate logistical regression analysis for ulceration risk was statistically significant for duration of diabetes (odds ratio [OR] = 0.8), smoking (OR = 9.7), foot deformity (OR = 8.7), MNDS (OR = 1.5), 2-h postprandial plasma glucose (2 h-PPG) (OR = 0.9), glycated hemoglobin (HbA1c) (OR = 2.1), FFPPP (OR = 1.0), and FFPPG (OR = 1.0).

CONCLUSION

In conclusion, persons with diabetes having neuropathy and/or ulcers have elevated PPP. Risk of ulceration was highly associated with duration of diabetes, smoking, severity of neuropathy, glycemic control, and high PP variables especially the FFPPP, F/R, and FFPPG. We suggest a cut-point of 355 kPa for FFPPP to denote high risk for ulceration that would be more valid when used in conjunction with other contributory risk factors, namely, duration of diabetes, smoking, glycemic load, foot deformity, and severity of neuropathy.

Windlass Mechanism in Individuals With Diabetes Mellitus, Peripheral Neuropathy, and Low Medial Longitudinal Arch Height

BACKGROUND

The windlass mechanism, acting through the plantar fascia, stabilizes the arches of the foot during stance phase of gait. The purpose of this study was to compare changes in radiographic measurements of the medial longitudinal arch (MLA) between toe-flat and -extended positions in participants with and without diabetes mellitus (DM), peripheral neuropathy (PN), and a low MLA.

METHODS

Twelve participants with DMPN and low MLA and 12 controls received weightbearing radiographs in a toe-flat and toe-extended position. DMPN participants were subcategorized from radiographs into DMPN severe, evidence of severe joint changes, and DMPN low, absence of joint changes. Primary measurements of MLA were determined in each position and included Meary's angle, talar declination angle, first metatarsal declination angle, and navicular height.

RESULTS

The DMPN severe group had no difference between toe-flat and -extended positions for Meary's, talar declination, and first metatarsal declination angles (P > .35) while navicular height elevated (P < .05). The DMPN low group had no difference between toe-flat and -extended positions for talar declination angle (P = .38), while Meary's angle, first metatarsal declination angle, and navicular height elevated (P < .05). All measurements in the control group changed, consistent with arch height elevation, when toes were extended (P < .05).

CONCLUSION

The DMPN severe and low groups showed impaired ability to raise the arch from the toe-flat to -extended position. Further research is needed to examine the contribution of specific windlass mechanism components (ie, plantar fascia, ligament, foot joint integrity, and mobility) as they relate to progressive foot deformity in adults with DMPN.

LEVEL OF EVIDENCE

Level III, comparative series.

Severity of pronation and classification of first metatarsophalangeal joint dorsiflexion increases the validity of the Hubscher Manoeuvre for the diagnosis of functional hallux limitus

BACKGROUND

Functional hallux limitus (FHL) is diagnosed with a static test known as the Hubscher Manoeuvre, the validity of which has been previously questioned.

OBJECTIVES

To investigate the validity of this Manoeuvre and whether introducing severity of pronation as a second concurrent test would increase this validity.

METHOD

30 participants with a hallux dorsiflexion <12° were divided into 2 equal groups, depending on their severity of pronation according to the Foot Posture Index. A single video camera, placed perpendicular to the plane of motion of the 1st MPJ, captured its movement, from which the angle of maximum dorsiflexion of this joint was measured.

RESULTS

10 males and 20 females, aged 18-56 years (mean 28 yrs, SD ± 12.1 yrs) participated. There was no significant relationship between non-weight bearing and dynamic maximum dorsiflexion (p=0.160), and between weight bearing and dynamic maximum dorsiflexion (p=0.865). A significant relationship between 1st MPJ dynamic maximum dorsiflexion and severity of pronation (p=0.004) was found.

CONCLUSIONS

None of the participants exhibited a complete lack of hallux dorsiflexion. A positive Hubscher Manoeuvre test, on its own, is not a good indicator of limited 1st MPJ dorsiflexion during dynamic motion. However, as pronation increases, 1st MPJ maximum dorsiflexion during gait decreases.