In this study, the 3D foot scanning data of 787 male participants were used to compare the foot shape of the recreational sprinters (n = 41) and non-habitual exercises (n = 746). Fourteen foot ...dimensions together with two foot type indicators were included in the comparison. The heel breadths of both feet of the recreational sprinters were significantly narrower than those of the non-habitual exercisers (p < 0.05), while the toe lengths of both feet of recreational sprinters were significantly longer than those of the non-habitual exercisers (p < 0.05). The participants' Arch Height Index (AHI) and Normalized Navicular Height Index (NNHI) suggested that on average the foot type for both groups fell into ‘normal arch foot’. Discriminant Analysis (DA) reached a hit ratio of 80.5%, which showed that the foot shapes of the recreational sprinters and non-habitual exercisers were distinguishable based on the foot dimensions. These findings could provide useful information for running shoe design and production.
•3D foot scanning data of 41 male recreational-sprinters and 746 male non-habitual exercisers were compared.•Ball girth circumference, height of navicular, and hallux of the right foot were significantly different across the groups.•Heel breadth and toe length of both feet were significantly different across the groups.•The foot dimensions and the identified differences provide useful information for running shoe design.
The human being's locomotion under the barefoot condition enables normal foot function and lower limb biomechanical performance from a biological evolution perspective. No study has demonstrated the ...specific differences between habitually barefoot and shod cohorts based on foot morphology and dynamic plantar pressure during walking and running. The present study aimed to assess and classify foot metrics and dynamic plantar pressure patterns of barefoot and shod people via machine learning algorithms. One hundred and forty-six age-matched barefoot (
= 78) and shod (
= 68) participants were recruited for this study. Gaussian Naïve Bayes were selected to identify foot morphology differences between unshod and shod cohorts. The support vector machine (SVM) classifiers based on the principal component analysis (PCA) feature extraction and recursive feature elimination (RFE) feature selection methods were utilized to separate and classify the barefoot and shod populations via walking and running plantar pressure parameters. Peak pressure in the M1-M5 regions during running was significantly higher for the shod participants, increasing 34.8, 37.3, 29.2, 31.7, and 40.1%, respectively. The test accuracy of the Gaussian Naïve Bayes model achieved an accuracy of 93%. The mean 10-fold cross-validation scores were 0.98 and 0.96 for the RFE- and PCA-based SVM models, and both feature extract-based and feature select-based SVM models achieved an accuracy of 95%. The foot shape, especially the forefoot region, was shown to be a valuable classifier of shod and unshod groups. Dynamic pressure patterns during running contribute most to the identification of the two cohorts, especially the forefoot region.
The goal of this paper is to quantify the shape of National Football League (NFL) players' feet and to identify foot shape characteristics that facilitate the development and refinement of ...position-specific footwear for NFL players. Statistical shape analysis was performed on three-dimensional (3 D) scans of 290 NFL players' feet obtained from 4 NFL teams during preseason training camps to identify the principal components that explain characteristics of the shape variability. Eight foot shape measurements were then defined to reflect the main principal components and were quantified. The foot volume, the arch shape in conjunction with the foot length, and the foot curvature explained more than 80% of the foot shape variation. The average foot length was 293 ± 13.7 mm and width was 110.6 ± 6.8 mm. Significant differences were observed between position groupings, primarily with regard to size. The prevalence of flat feet (defined as 0 arch depth) was greater in linemen and hybrid position groups than in the skill group. This information can facilitate improvements in the lasts used to create shoes for elite-level players and can also help inform footwear selection.
Background
Foot morphology has received increasing attention from both biomechanics researches and footwear manufacturers. Usually, the morphology of the foot is quantified by 2D footprints. However, ...footprint quantification ignores the foot's vertical dimension and hence, does not allow accurate quantification of complex 3D foot shape.
Methods
The shape variation of healthy 3D feet in a population of 31 adult women and 31 adult men who live in Belgium was studied using geometric morphometric methods. The effect of different factors such as sex, age, shoe size, frequency of sport activity, Body Mass Index (BMI), foot asymmetry, and foot loading on foot shape was investigated. Correlation between these factors and foot shape was examined using multivariate linear regression.
Results
The complex nature of a foot's 3D shape leads to high variability in healthy populations. After normalizing for scale, the major axes of variation in foot morphology are (in order of decreasing variance): arch height, combined ball width and inter‐toe distance, global foot width, hallux bone orientation (valgus‐varus), foot type (e.g. Egyptian, Greek), and midfoot width. These first six modes of variation capture 92.59% of the total shape variation. Higher BMI results in increased ankle width, Achilles tendon width, heel width and a thicker forefoot along the dorsoplantar axis. Age was found to be associated with heel width, Achilles tendon width, toe height and hallux orientation. A bigger shoe size was found to be associated with a narrow Achilles tendon, a hallux varus, a narrow heel, heel expansion along the posterior direction, and a lower arch compared to smaller shoe size. Sex was found to be associated with differences in ankle width, Achilles tendon width, and heel width. Frequency of sport activity was associated with Achilles tendon width and toe height.
Conclusion
A detailed analysis of the 3D foot shape, allowed by geometric morphometrics, provides insights in foot variations in three dimensions that can not be obtained from 2D footprints. These insights could be applied in various scientific disciplines, including orthotics and shoe design.
Fall is a very common injury, especially in older adults with foot deformities and other foot disorders. Even a small fall may cause fatal damage to this cohort. The purpose of this study was to ...conduct a review elucidating plantar pressure pattern under different foot deformities in the elderly. English-language search of the electronic databases in PubMed, ScienceDirect, Google Scholar, and Web of Science was conducted from 2000 to May 2020. Fifteen studies were found after literature searching and screening. Among them, 2 studies described the plantar pressure of plantar hyperkeratosis lesions in the elderly, 2 studies depicted the plantar pressure of pronated foot supinated foot in the elderly, 4 studies explored the plantar pressure distribution of hallux valgus and other foot deformities, and 7 studies focused on the plantar pressure of diabetic foot deformity in the elderly. Foot deformity appears to alter the plantar pressure in the elderly, and plantar pressure characteristics differ according to foot deformities.
Detailed understanding of the foot deformation during walking is important for ergonomic design of shoe and orthopaedic diagnosis. However, quantitative description of the foot deformation and skin ...strain during walking have not been fully investigated due to difficulty of measurement. In this study, we aimed to clarify the three-dimensional (3D) human foot deformation and the foot skin strain during bipedal walking by means of digital image correlation (DIC) method. The 3D-DIC method is an optical method to measure 3D deformation of an object by using the stereo-triangulation and the image correlation of speckle pattern on the object surface. Five adult male participants were asked to walk along a walkway at a self selected speed. The dorso-lateral and medial surfaces of the right foot during the stance phase of bipedal walking were filmed using four synchronized high speed cameras. The right foot surface was sprayed with aqueous black ink to draw the speckle pattern. We calculated time change in the 3D foot shape and the skin strain distribution during walking. The accuracy of the shape and deformation measurement was confirmed to be about 0.1 mm, sufficiently accurate for quantitative description of the foot deformation. Our results demonstrated that in the early and late stance phase, the foot surface around the cuboid were stretched in the mediolateral direction. In the late stance phase, the lateral surface of the rear foot was stretched in the dorsopalmar direction vice versa in the medial surface. Proposed methodology may serve as an effective tool to clarify how external surface of the human foot dynamically behaves during walking.
Wedge-heeled shoes, which are formed by elevating both the forefoot and heel, have been popular among young women. However, research on the foot shape in wedge-heeled shoes is lacking. This study ...aimed to access the effects of forefoot height (10, 20, and 30 mm) and heel height (30, 50, 70, and 90 mm) on foot shape and perceived comfort when wearing wedge-heeled shoes. Three-dimensional (3D) foot scanning was performed on 35 females and the 14 foot dimensions were measured. Increased forefoot height generated larger lengths (foot, ball and out ball), smaller girths (ball and instep) and heights (instep and navicular) (
p
< 0.05). Thus, when the forefoot height increased, the foot became longer, slimmer and flatter. Moreover, elevated heel height resulted in larger dimensions for girths (ball and instep), heights (instep and navicular), and smaller dimensions for lengths (foot, ball and out ball), widths (diagonal and horizontal) and toe 5 angles of the foot (
p
< 0.01). That means shorter, narrower and more convex foot shapes were observed when heel height increased. Subjective measurements implied that increased forefoot height significantly enhanced perceived comfort, whereas increased heel height diminished comfort. It was found that forefoot elevation could result in less deformation and discomfort which accompanied heel elevation, especially in the low heel-toe drop combinations (10 × 30 and 20 × 30 mm). The findings provide valuable references for enhancing shoe fitting and comfort for wedge-heeled shoes by providing dimensional data on the toe, ball, arch and instep regions.
The theory that footwear may change foot shape dates back 100 years. Since this period, research has revealed the anatomical and functional consequences that footwear can cause to the foot. ...Children's feet remain malleable as they undergo developmental changes until adolescence, which is why childhood is arguably a crucial period to understand how footwear can affect natural foot development. This review explored the development of the foot in children and adolescents and the methods used to measure the different foot structures; it comments on the key issues with some of these methods and gives direction for future research. Various internal and external factors can affect foot development; the main factors are age, gender, ethnicity, body mass index (BMI) and footwear habits. Research on how footwear can affect foot development has increased over the years and the final section of this review aimed to unpick the findings. Studies investigating the influence of footwear habits on foot length and width have established inconsistent findings. Many of the studies in the review did not control for internal and external factors that can affect foot development. There was also a limited number of studies that investigated hallux valgus angle and muscle strength differences in those with different footwear habits. Moreover, multiple studies in the final section of this review did not successfully examine the footwear habits of the participants and instead used observations or self-assessments, which is a major limitation. Future research should examine footwear behaviors and other confounding factors when investigating the development of the foot in children and adolescents. Moreover, researchers should critically evaluate the methods used to quantify the different structures of the foot to ensure valid and reliable parameters are being used.
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