The influence of population characteristics and measurement system on barefoot plantar pressures: A systematic review and meta-regression analysis

Evaluation of foot support characteristics in young and elderly adults by plantar measurements based on a three-partition distributed force platform

A three-partition distributed force platform (3P-DFP) is proposed to measure the plantar pressure distribution, and foot support characteristics are evaluated with the obtained pressure distribution information. Twenty-seven young adults and 40 elderly adults were randomly recruited to perform the test in three phases: double-leg stance with eyes closed, double-leg stance with eyes opened, and single-leg stance with eyes opened. The evaluation parameters of foot support surface characteristics and support point characteristics were calculated based on the average position information of the center of pressure in the lateral of sole, media of sole, posterior of heel, and entire pelma. The results showed that the support width of the foot sole was significantly greater in the elderly group (p <0.01), but the overall support area showed a decreasing trend. The CoP excursion in the media-lateral direction was significantly higher in the elderly group from double-leg stance to single-leg stance (p <0.01). The CoP trajectory in the elderly group tends to shift in a medial direction with increasing age or postural difficulty.

Correlations between plantar pressure and postural balance in healthy subjects and their comparison according to gender and limb dominance: A cross-sectional descriptive study

BACKGROUND

Lower extremity injuries rank among the most common injuries affecting young population, and numerous factors affect the outcomes of plantar pressure and balance assessment.

RESEARCH QUESTION

Does a correlation exist between plantar pressure and postural balance in healthy subjects and are there any difference in the results based on gender and limb dominance?

METHODS

This study involved thirty healthy recreationally active young adults (15 females, 15 males). Plantar pressures were analyzed using the MatScan Pressure Mat System, and postural balance was evaluated using Biodex Balance System. All assessments conducted under both static and dynamic conditions. Correlations were tested by Spearman Correlation Coefficient, and comparative tests were performed for gender and limb dominance.

RESULTS

Correlations were observed between plantar pressure parameters and balance scores, particularly in the dynamic conditions (p < 0.05). Gender-based differences were noted in plantar pressure parameters (p < 0.05), with females demonstrating improved balance stability scores. No significant differences were found based on limb dominance in plantar pressure and postural balance data (p > 0.05).

SIGNIFICANCE

This study provides valuable detailed insights into the existing literature concerning plantar pressure and postural balance assessments within the healthy population. A strong correlation was observed between plantar pressure and postural balance, and the comparisons of these assessments were affected by gender but not by limb dominance. These results could lead the way for better rehabilitation approaches by considering the correlations and differences across diverse populations.

pressuRe: an R package for analyzing and visualizing biomechanical pressure distribution data

In many biomechanical analyses, the forces acting on a body during dynamic and static activities are often simplified as point loads. However, it is usually more accurate to characterize these forces as distributed loads, varying in magnitude and direction, over a given contact area. Evaluating these pressure distributions while they are applied to different parts of the body can provide effective insights for clinicians and researchers when studying health and disease conditions, for example when investigating the biomechanical factors that may lead to plantar ulceration in diabetic foot disease. At present, most processing and analysis for pressure data is performed using proprietary software, limiting reproducibility, transparency, and consistency across different studies. This paper describes an open-source software package, 'pressuRe', which is built in the freely available R statistical computing environment and is designed to process, analyze, and visualize pressure data collected on a range of different hardware systems in a standardized manner. We demonstrate the use of the package on pressure dataset from patients with diabetic foot disease, comparing pressure variables between those with longer and shorter durations of the disease. The results matched closely with those from commercially available software, and individuals with longer duration of diabetes were found to have higher forefoot pressures than those with shorter duration. By utilizing R's powerful and openly available tools for statistical analysis and user customization, this package may be a useful tool for researchers and clinicians studying plantar pressures and other pressure sensor array based biomechanical measurements. With regular updates intended, this package allows for continued improvement and we welcome feedback and future contributions to extend its scope. In this article, we detail the package's features and functionality.

Understanding foot conditions, morphologies and functions in children: a current review

This study provided a comprehensive updated review of the biological aspects of children foot morphology across different ages, sex, and weight, aiming to reveal the patterns of normal and pathological changes in children feet during growth and development. This review article comprised 25 papers in total that satisfied the screening standards. The aim was to investigate how weight changes, age and sex affect foot type, and gain a deeper understanding of the prevalent foot deformities that occur during children growth. Three different foot morphological conditions were discussed, specifically including the effect of sex and age differences, the effect of weight changes, and abnormal foot morphologies commonly documented during growth. This review found that sex, age, and weight changes would affect foot size, bony structure, foot posture, and plantar pressures during child growth. As a result of this biological nature, the children's feet generally exhibit neutral and internally rotated foot postures, which frequently lead to abnormal foot morphologies (e.g., flat foot, pronated foot, etc.). In the future, attention shall be paid to the causal factors leading to specific foot morphologies during the growth and development of children. However, sufficient evidence could not be provided due to a relatively short period of investigation and non-uniformed research methodology in the current literature. A more comprehensive and in-depth exploration is recommended to provide scientific evidence for the discovery of children foot development and personalized growth pattern.

Sex differences in diabetic foot ulcer severity and outcome in Belgium

BACKGROUND

Sex differences are increasingly recognized to play an important role in the epidemiology, treatment and outcomes of many diseases. This study aims to describe differences between sexes in patient characteristics, ulcer severity and outcome after 6 months in individuals with a diabetic foot ulcer (DFU).

METHODS

A total of 1,771 patients with moderate to severe DFU participated in a national prospective, multicenter cohort study. Data were collected on demographics, medical history, current DFU and outcome. For data analysis, a Generalized Estimating Equation model and an adjusted Cox proportional hazards regression were used.

RESULTS

The vast majority of patients included were male (72%). Ulcers in men were deeper, more frequently displaying probe to bone, and more frequently deeply infected. Twice as many men presented with systemic infection as women. Men demonstrated a higher prevalence of previous lower limb revascularization, while women presented more frequently with renal insufficiency. Smoking was more common in men than in women. No differences in presentation delay were observed. In the Cox regression analysis, women had a 26% higher chance of healing without major amputation as a first event (hazard ratio 1.258 (95% confidence interval 1.048-1.509)).

CONCLUSIONS

Men presented with more severe DFU than women, although no increase in presentation delay was observed. Moreover, female sex was significantly associated with a higher probability of ulcer healing as a first event. Among many possible contributing factors, a worse vascular state associated with a higher rate of (previous) smoking in men stands out.

Wearable Device Validity in Measuring Steps, Energy Expenditure, and Heart Rate Across Age, Gender, and Body Mass Index: Data Analysis From a Systematic Review

BACKGROUND

This paper examined whether the criterion validity of step count (SC), energy expenditure (EE), and heart rate (HR) varied across studies depending on the average age, body mass index (BMI), and predominant gender of participants.

METHODS

Data from 1536 studies examining the validity of various wearable devices were used. Separate multilevel regression models examined the associations among age, gender, and BMI with device criterion validity assessed using mean absolute percent error (MAPE) at the study level.

RESULTS

MAPE values were reported in 970 studies for SC, 328 for EE, and 238 for HR, respectively. There were several significant differences in MAPE between age, gender, and BMI categories for SC, EE, and HR. SC MAPE was significantly different for older adults compared with adults. Compared with studies among normal-weight populations, MAPE was greater among studies with overweight samples for SC, HR, and EE. Comparing studies with more women than men, MAPE was significantly greater for EE and HR.

CONCLUSIONS

There are important differences in the criterion validity of commercial wearable devices across studies of varying ages, BMIs, and genders. Few studies have examined differences in error between different age groups, particularly for EE and HR.

Backward vs. Forward Gait Symmetry Analysis Based on Plantar Pressure Mapping

Symmetry is one of the factors analysed in normal and pathological gaits. Backward gait is an area of interest to scientists, in terms of its physiology and therapeutic possibilities. This study aimed to analyse the symmetry of the pressure parameters of backward gait in comparison to forward gait using different symmetry indices. Eighty-one healthy people aged between 19 and 84 years took part in the study. Foot pressure distribution was analysed during forward and backward gaits at self-selected speeds. Mean and maximum pressure values were calculated after dividing the foot into four or ten areas. Delta, Ratio Index, Robinson Index, Gait Asymmetry, and Symmetry Angle were calculated for each area, separately for both forward and backward gaits. Higher ratios of asymmetry were found during backward than during forward gait. Larger ratios of asymmetry were found within toes II–V, forefoot, metatarsals I, II, and III, medial and lateral heel areas. No significant correlation between symmetry indices and age or BMI was found. Results suggested that the lower symmetry of backward gait is caused by a higher number of corrective movements that allow for the maintenance of body balance and global symmetry of gait. This can be realised by increased cortical control of the backward gait, which was a new movement task for all participants.

Pedobarography in Physiotherapy: A Narrative Review on Current Knowledge

Pedobarography is a modern technology enabling the assessment of the locomotor system based on the plantar pressure distribution. The technic is useful in the rehabilitation of various types of dysfunction of body movement. This chapter aims to describe the application of pedobarography in clinical therapy. The qualitative analysis is based on a review of articles in English, French, German, Polish, Portuguese, Spanish, Turkish, and Chinese in Medline/PubMed, Cochrane Library, Embase, and PEDro databases. The search covered the articles on clinical trials, randomized controlled trials, meta-analyses, and reviews published over 1984-2020. The literature shows that pedobarography is a safe non-invasive method that is useful for the examination of foot biomechanics with a reference to the entire musculoskeletal system. A pedobarographic examination enables insight into a motion disorder, its plausible relation to a systemic pathology, and monitoring the course of treatment and rehabilitation.

Influence of dental occlusion conditions on plantar pressure distribution during standing and walking - A gender perspective

The aim of this study was to investigate gender-specific influences of different symmetric and asymmetric occlusion conditions on postural control during standing and walking. The study involved 59 healthy adult volunteers (41 f/19 m) aged between 22 and 53 years (30.2 ± 6.3 years). Postural control measurements were carried out using a pressure plate by measuring plantar pressure distribution during standing and walking test conditions. Seven different occlusion conditions were tested. Prior to a MANOVA model analysis, the relationship between the two test conditions were checked using a factor analysis with a varying number of factors (between 2 and 10). The plantar pressure distributions during walking and standing are independent test conditions. The coefficient of variance across all variables between the conditions and genders was not significant: t(46) = 1.51 (p = 0.13). No statement can be made whether, or not, the influence of gender is greater than the influence of the conditions. Healthy male and female test subjects did not show any difference between seven occlusion conditions on the plantar pressure distribution while standing or walking. No differences between the genders were found for any of the investigated variables. In contrast to custom-made occlusion splints, simple cotton rolls appear not to influence the neuromuscular system in a systematic manner.

Recommendations for determining the validity of consumer wearable and smartphone step count: expert statement and checklist of the INTERLIVE network

Consumer wearable and smartphone devices provide an accessible means to objectively measure physical activity (PA) through step counts. With the increasing proliferation of this technology, consumers, practitioners and researchers are interested in leveraging these devices as a means to track and facilitate PA behavioural change. However, while the acceptance of these devices is increasing, the validity of many consumer devices have not been rigorously and transparently evaluated. The Towards Intelligent Health and Well-Being Network of Physical Activity Assessment (INTERLIVE) is a joint European initiative of six universities and one industrial partner. The consortium was founded in 2019 and strives to develop best-practice recommendations for evaluating the validity of consumer wearables and smartphones. This expert statement presents a best-practice consumer wearable and smartphone step counter validation protocol. A two-step process was used to aggregate data and form a scientific foundation for the development of an optimal and feasible validation protocol: (1) a systematic literature review and (2) additional searches of the wider literature pertaining to factors that may introduce bias during the validation of these devices. The systematic literature review process identified 2897 potential articles, with 85 articles deemed eligible for the final dataset. From the synthesised data, we identified a set of six key domains to be considered during design and reporting of validation studies: target population, criterion measure, index measure, validation conditions, data processing and statistical analysis. Based on these six domains, a set of key variables of interest were identified and a 'basic' and 'advanced' multistage protocol for the validation of consumer wearable and smartphone step counters was developed. The INTERLIVE consortium recommends that the proposed protocol is used when considering the validation of any consumer wearable or smartphone step counter. Checklists have been provided to guide validation protocol development and reporting. The network also provide guidance for future research activities, highlighting the imminent need for the development of feasible alternative 'gold-standard' criterion measures for free-living validation. Adherence to these validation and reporting standards will help ensure methodological and reporting consistency, facilitating comparison between consumer devices. Ultimately, this will ensure that as these devices are integrated into standard medical care, consumers, practitioners, industry and researchers can use this technology safely and to its full potential.

Reprodutibilidade e concordância entre diferentes protocolos de baropodometria dinâmica durante a marcha: um estudo preliminar

RESUMO A identificação da pressão plantar durante a marcha é utilizada por clínicos e investigadores para verificar sobrecarga na estrutura podal. Neste particular, diferentes protocolos têm sido empregados para essa finalidade. O objetivo do estudo foi verificar a reprodutibilidade e a concordância de protocolos abreviados de marcha para identificar a pressão plantar dinâmica em jovens assintomáticos. Quinze voluntários foram submetidos aos protocolos abreviados one-step e three-step e ao protocolo padrão midgait em três momentos: inicial, dia seguinte e após sete dias. Para cada uma das oito máscaras podais, foram consideradas as medidas de pico de pressão plantar e integral pressão/tempo. A reprodutibilidade foi analisada mediante Anova one-way e coeficiente de correlação intraclasse, enquanto a concordância entre os protocolos foi verificada através de teste t pareado, correlação momento-produto de Pearson e plotagem de Bland-Altman. Os resultados apontaram que o protocolo three-step apresentou mais elevada reprodutibilidade em ambas as medidas de pressão plantar dinâmica. Quanto à concordância entre os protocolos, apesar de os abreviados demonstrarem tendência em subestimar as medidas produzidas pelo protocolo padrão midgait, na maioria das máscaras podais não foram identificadas diferenças estatísticas entre os escores médios. Ainda, por intermédio da técnica de Bland-Altman, constatou-se substancial capacidade de concordância entre as medidas identificadas pelos protocolos one-step, three-step e midgait. Concluindo, os protocolos abreviados devem ser selecionados de acordo com a medida de interesse da pressão plantar e a máscara podal a ser analisada, surgindo evidências de reprodutibilidade e concordância mais favoráveis para o uso do protocolo three-step.

The Impact of Overweight and Obesity on Plantar Pressure in Children and Adolescents: A Systematic Review

We aimed to synthesise the results of previous studies addressing the impact of overweight and obesity on plantar pressure in children and adolescents. An electronic search of scientific literature was conducted using PubMed, Cochrane and Scopus database, with keywords: “plantar pressure” AND “children” AND “obesity”; “plantar pressure” AND “adolescents” AND “obesity”, “plantar pressure” AND “children” AND “overweight”, “plantar pressure” AND “adolescents” AND “overweight”. Twenty-two articles were included in the review and the following data were recorded: authors, publication year, type of technology (systems, software) for the determination of plantar pressure, study characteristics. Most of the articles used dynamic plantar pressure determination with only four using static plantar pressure measurement. Using ultrasonography with static plantar pressure determination, the correlation between structural and functional changes in the feet of obese children. In overweight and obese children and adolescents, important findings were recorded: higher contact area, increased maximum force beneath the lateral and medial forefoot, increased pressure–time integral beneath the midfoot and 2nd–5th metatarsal regions. Significantly increased foot axis angle and significantly flatter feet were observed in obese subjects in comparison to their normal-weight counterparts. The obese children presented increased midfoot fat pad thickness, with decreased sensitivity of the whole foot and midfoot.

PAPPI: Personalized analysis of plantar pressure images using statistical modelling and parametric mapping

Quantitative analyses of plantar pressure images typically occur at the group level and under the assumption that individuals within each group display homogeneous pressure patterns. When this assumption does not hold, a personalized analysis technique is required. Yet, existing personalized plantar pressure analysis techniques work at the image level, leading to results that can be unintuitive and difficult to interpret. To address these limitations, we introduce PAPPI: the Personalized Analysis of Plantar Pressure Images. PAPPI is built around the statistical modelling of the relationship between plantar pressures in healthy controls and their demographic characteristics. This statistical model then serves as the healthy baseline to which an individual’s real plantar pressures are compared using statistical parametric mapping. As a proof-of-concept, we evaluated PAPPI on a cohort of 50 hallux valgus patients. PAPPI showed that plantar pressures from hallux valgus patients did not have a single, homogeneous pattern, but instead, 5 abnormal pressure patterns were observed in sections of this population. When comparing these patterns to foot pain scores (i.e. Foot Function Index, Manchester-Oxford Foot Questionnaire) and radiographic hallux angle measurements, we observed that patients with increased pressure under metatarsal 1 reported less foot pain than other patients in the cohort, while patients with abnormal pressures in the heel showed more severe hallux valgus angles and more foot pain. Also, incidences of pes planus were higher in our hallux valgus cohort compared to the modelled healthy controls. PAPPI helped to clarify recent discrepancies in group-level plantar pressure studies and showed its unique ability to produce quantitative, interpretable, and personalized analyses for plantar pressure images.

Plantar pressures in identical and non-identical twins

Identifying environmental risk factors for musculoskeletal disorders is challenging due to the number of potential confounders. Twins are of particular interest for researchers interested in studying these types of problems due to their inherent control for the influence of genetic factors. In twin studies, this population can allow environmental risk factors to be more easily identified, and this type of study design may allow the role of biomechanics in injury and disease to be further explored. At present, it is unclear if foot function displays more similarity between certain types of twins. In this study, we hypothesized that the plantar pressures of monozygotic (identical) twins would be more similar between pairs than dizygotic (non-identical) twins. We measured static and dynamic plantar pressures from five pairs of each twin type. Statistical parametric modeling was used to compare pressure distributions at the sensor level. For >80% of stance phase, the pixel level analysis indicated that monozygotic twins had less variation in plantar pressure between pairs. The average z-statistic across the entire trial was 0.88 for the monozygotic group and 1.13 for the dizygotic group. In this study we provide evidence of greater similarity of plantar pressures in monozygotic twin pairs compared to dizygotic twins. This finding supports the use of co-twin studies investigating potentially modifiable environmental and biomechanical risk factors for musculoskeletal conditions that affect the foot and ankle.