Foot Arch Height and Quality of Life in Adults: A Strobe Observational Study

Adult Acquired Flatfoot Deformity: A Narrative Review about Imaging Findings

Adult acquired flatfoot deformity (AAFD) is a disorder caused by repetitive overloading, which leads to progressive posterior tibialis tendon (PTT) insufficiency. It mainly affects middle-aged women and occurs with foot pain, malalignment, and loss of function. After clinical examination, imaging plays a key role in the diagnosis and management of this pathology. Imaging allows confirmation of the diagnosis, monitoring of the disorder, outcome assessment and complication identification. Weight-bearing radiography of the foot and ankle are gold standard for the diagnosis of AAFD. Magnetic Resonance Imaging (MRI) is not routinely needed for the diagnosis; however, it can be used to evaluate the spring ligament and the degree of PTT damage which can help to guide surgical plans and management in patients with severe deformity. Ultrasonography (US) can be considered another helpful tool to evaluate the condition of the PTT and other soft-tissue structures. Computed Tomography (CT) provides enhanced, detailed visualization of the hindfoot, and it is useful both in the evaluation of bone abnormalities and in the accurate evaluation of measurements useful for diagnosis and post-surgical follow-up. Other state-of-the-art imaging examinations, like multiplanar weight-bearing imaging, are emerging as techniques for diagnosis and preoperative planning but are not yet standardized and their scope of application is not yet well defined. The aim of this review, performed through Pubmed and Web of Science databases, was to analyze the literature relating to the role of imaging in the diagnosis and treatment of AAFD.

The spectrum of foot deformities in Loeys-Dietz syndrome

Loeys-Dietz syndrome (LDS) is characterized by a wide spectrum of musculoskeletal manifestations, including foot deformities. The spectrum of foot deformities in LDS has not been previously characterized. Our objective was to describe the incidence and characteristics of foot deformities in LDS. We retrospectively reviewed the demographic, clinical and imaging data for patients diagnosed with LDS who were seen at our Orthopedic surgery department from 2008 to 2021. We performed descriptive analyses and compared distributions of deformities by LDS genetic mutations. Of the 120 patients studied, most presented for evaluation of foot deformities ( N  = 56, 47%) and scoliosis ( N  = 45; 38%). Ninety-seven patients (81%) had at least one foot deformity, and 87% of these patients had bilateral foot deformities. The most common deformities were pes planovalgus (53%) and talipes equinovarus (34%). Of patients with foot deformities, 58% presented for evaluation of the feet. Of patients with pes planovalgus, only 17% presented for evaluation of the feet. Among patients with pes planovalgus, 2% underwent surgery and 16% used orthotics compared with 76% and 42%, respectively, for patients with talipes equinovarus. We found no association between deformities and genetic mutations. Bilateral foot deformities are highly prevalent in patients with LDS and are the most common reason for presentation to orthopedic surgeons. Although pes planovalgus is the most common deformity, it rarely prompted surgical treatment. Orthopedic surgeons treating LDS patients should be aware of the unique characteristics of foot deformities in LDS.

Characteristics of paediatric foot arches according to body mass among primary school students in Wrocław, Poland

Background

The purpose of this study, conducted within the framework of the project entitled ‘Let’s get the kids moving’, was to determine the associations between children’s longitudinal and transverse foot arch and their weight, gender and age.

Method

The pro-health initiative ‘Let’s get the kids moving’ was created by researchers of the Medical University and the Run for Health Foundation. A total of 655 children (51.5% boys) aged 7 to 10 years from primary schools in south-western Poland participated in the study. The mean age of the subjects was 8.7 ± 0.8 years. In all the children, we assessed anthropometric measurements (weight and height) and the longitudinal and transverse arch of the foot under the load of their weight. A two-dimensional foot scanner (Sensor Medica, Italy) was used to examine the plantar part of the children’s feet.

Results

The data collected from the 655 subjects revealed that excessive weight predisposed them to less longitudinal and transverse arching. The foot shape was not differentiated by gender or age.

Conclusions

Screening school-aged children’s footprints can detect abnormalities in the shape of children’s feet early on, which allows for early diagnosis of functional or structural flatfoot in children.

Diagnostic Accuracy of Various Radiological Measurements in the Evaluation and Differentiation of Flatfoot: A Cross-Sectional Study

Arch angle is used to indicate flatfoot, but in some cases, it is not easily defined. The presence of flatfoot deformity remains difficult to diagnose due to a lack of reliable radiographic assessment tools. Although various assessment methods for flatfoot have been proposed, there is insufficient evidence to prove the diagnostic accuracy of the various tools. The main purpose of the study was to determine the best radiographic measures for flatfoot concerning the arch angle. Fifty-two feet radiographs from thirty-two healthy young females were obtained. Five angles and one index were measured using weight-bearing lateral radiographs; including arch angle, calcaneal pitch (CP), talar-first metatarsal angle (TFM), lateral talar angle (LTA), talar inclination angle (TIA) and navicular index (NI). Receiver-operating characteristics were generated to evaluate the flatfoot diagnostic accuracy for all radiographic indicators and Matthews correlation coefficient was calculated to determine the cutoff value for each measure. The strongest correlation was between arch angle and CP angle [r = −0.91, p ≤ 0.0001, 95% confidence interval (CI) (from −0.94 to −0.84)]. Also, significant correlations were found between arch angle and NI [r = 0.62, p ≤ 0.0001, 95% CI (0.42 to 0.76)], and TFM [r = 0.50, p ≤ 0.0001, 95% CI (from 0.266 to 0.68)]. Furthermore, CP (cutoff, 12.40) had the highest accuracy level with value of 100% sensitivity and specificity followed by NI, having 82% sensitivity and 89% specificity for the cutoff value of 9.90. In conclusion, CP angle is inversely correlated with arch angle and considered a significant indicator of flatfoot. Also, the NI is easy to define radiographically and could be used to differentiate flat from normal arched foot among young adults.

Foot Deformity in Patients With Ankylosing Spondylitis: Is It Associated With Functionality and Disease Activity?

Foot involvement affects mobility and functionality in patients with ankylosing spondylitis but it remains unknown if foot deformities in ankylosing spondylitis patients affect functionality, disease activity, and quality of life. The aim of this study was to evaluate in detail the presence of a relationship between radiologically detected foot deformities in ankylosing spondylitis patients and both clinical and electrophysiological findings. The cross-sectional study included 110 patients with ankylosing spondylitis who were diagnosed according to the Assessment in Spondyloarthritis International Society criteria and were followed in our hospital. Demographic and clinical data of all patients were recorded. Bilateral lateral foot x-rays and electrophysiology examinations were evaluated in all subjects. The arch in the dominant foot of the patients was classified in 3 groups as pes cavus, pes planus, or normal. The clinical outcomes, physical examination and electrophysiological findings were compared between the groups, and correlations were examined of the foot deformities with these parameters. Foot deformities were determined at a high rate (74.5%). These deformities affected foot pain, disability and quality of life. Pes cavus deformity was found to be associated with hip pain and enthesopathy. In the electrophysiological studies, the presence of pes planus was found to be associated with the findings of the tibial and sural nerve conduction studies, and the presence of pes cavus with the findings of the peroneal nerve conduction study. In conclusion, foot deformities may have an effect on the quality of life and functionality in ankylosing spondylitis patients.

Non-invasive and quantitive analysis of flatfoot based on ultrasound

Flatfoot is a common foot deformity that seriously affects the quality of life. The aim of this study is to develop an accurate and noninvasive method for the diagnosis of flatfoot based on B-mode ultrasound. In this study, 51 patients (the flatfoot group) and 43 healthy subjects (the control group) were included. The plantar fascia angle, a new measurement for use in the diagnosis of flatfoot is proposed, as determined using B-mode ultrasound. For comparison, the calcaneal pitch angle and medial cuneiform height were also measured using lateral X-radiography, based on traditional diagnostic methods. The intraclass correlation values of the plantar fascia angle, the calcaneal pitch angle, and the medial cuneiform height were all more than 0.95, and there is a moderate correlation (r = 0.51) between the medial cuneiform height and the calcaneal pitch angle, and an excellent correlation (r = 0.85) between the plantar fascia angle and the calcaneal pitch angle. The optimal cutoff value, sensitivity, and specificity for medial cuneiform height in flatfoot diagnosis were 12.8 mm, 93.0%, and 54.9%, respectively. The optimal cutoff value, sensitivity, and specificity for plantar fascia angle in flatfoot diagnosis were 9.8°, 97.7%, and 94.1%, respectively. The proposed plantar fascia angle has good sensitivity and specificity in diagnosing flatfoot, therefore supplying a new approach for the noninvasive diagnosis of flatfoot.

Early Notice Pointer, an IoT-like Platform for Point-of-Care Feet and Body Balance Screening

Improper foot biomechanics associated with uneven bodyweight distribution contribute to impaired balance and fall risks. There is a need to complete the panel of commercially available devices for the self-measurement of BMI, fat, muscle, bone, weight, and hydration with one that measures weight-shifting at home as a pre-specialist assessment system. This paper reports the development of the Early Notice Pointer (ENP), a user-friendly screening device based on weighing scale technology. The ENP is designed to be used at home to provide a graphic indication and customised and evidence-based foot and posture triage. The device electronically detects and maps the bodyweight and distinct load distributions on the main areas of the feet: forefoot and rearfoot. The developed platform also presents features that assess the user's balance, and the results are displayed as a simple numerical report and map. The technology supports data display on mobile phones and accommodates multiple measurements for monitoring. Therefore, the evaluation could be done at non-specialist and professional levels. The system has been tested to validate its accuracy, precision, and consistency. A parallel study to describe the frequency of arch types and metatarsal pressure in young adults (1034 healthy subjects) was conducted to explain the importance of self-monitoring at home for better prevention of foot arch- and posture-related conditions. The results showed the potential of the newly created platform as a screening device ready to be wirelessly connected with mobile phones and the internet for remote and personalised identification and monitoring of foot- and body balance-related conditions. The real-time interpretation of the reported physiological parameters opens new avenues toward IoT-like on-body monitoring of human physiological signals through easy-to-use devices on flexible substrates for specific versatility.

Effect of Longitudinal and Transverse Foot Arch on the Position of the Hallux and Fifth Toe in Preschool Children in the Light of Regression Analysis

The aim of the study was to analyze the development of foot structure and the impact of longitudinal and transverse arching of the foot on the position of the hallux and fifth toe in preschool children. The study was carried out among 200 children aged 6 (100 G, 100 B). The research tool was the podoscope CQ-ST. The collected research results were analyzed with the use of the Mann–Whitney U test, Pearson Chi-square test and regression analysis. A statistically significant influence of the heel angle on the value of the varus angle of the fifth toe of the right (girls: p = 0.032; boys: p = 0.001) and left foot (girls: p = 0.004; boys: p = 0.005) was found. Boys’ feet are longer and wider than girls’ feet; moreover, they have a lower longitudinal arch. The frequency of longitudinal and transverse arch deformities of the feet, as well as valgus of the hallux and varus of the fifth toe do not depend on gender. In both sexes, decreasing the transverse arch of the foot has an influence on the severity of varus of the fifth toe. Changes in the height of the longitudinal foot arch does not affect the position of the hallux and fifth toe.

Immediate comfort perception of 3D-printed foot orthoses in individuals with unilateral heel pain

BACKGROUND

Custom-made foot orthoses (FOs) play an integral part in managing foot disorders. Traditional FO fabrication is time-consuming and labor intensive. Three-dimensional (3D) printed FOs save time and cost compared with the traditional manufacturing process. To date, the differences in dimensions and comfort perception of these orthoses have not been compared in a pathological population.

OBJECTIVE

Compare the dimensions between 3D-printed and traditionally made FOs and comfort perception between 3D-printed, traditionally made, and no FOs in individuals with flatfeet and unilateral heel pain.

STUDY DESIGN

Within-subject single-blinded randomized crossover study design.

METHODS

Thirteen participants had custom-made FOs using 3D-printing and traditional processes. Orthotic lengths, widths, arch heights, and heel cup heights were compared. Participants performed walking trials under three conditions: (1) no orthoses, (2) 3D-printed orthoses, and (3) traditionally made orthoses. Comfort perception was recorded. Orthotic dimensions were compared using paired t tests, and comfort perception were compared using one-way multiple analysis of variance and Bonferroni post hoc tests.

RESULTS

Three-dimensional-printed orthoses were wider, have higher arch heights, and heel cup heights compared with traditionally made FOs (medium to large effect sizes). There was a difference in comfort perception between the three orthotic conditions, F(12,62) = 1.99, P = 0.04; Wilk Λ = 0.521, ηp2= 0.279. Post hoc tests show that there is no difference in comfort perception between the 3D-printed and traditionally made FOs. Both FOs were significantly more comfortable than no orthoses.

CONCLUSIONS

Three-dimensional printing seems to be a viable alternative orthotic fabrication option. Future studies should compare the biomechanical effects of 3D-printed and traditionally made FOs.

Effect of Plano-Valgus Foot on Lower-Extremity Kinematics and Spatiotemporal Gait Parameters in Children of Age 5–9

Aim of the study was to see how a definition of the flexible flat foot (FFF) influences the results of gait evaluation in a group of 49 children with clinically established FFF. Objective gait analysis was performed using VICON system with Kistler force platforms. The gait parameters were compared between healthy feet and FFF using two classifications: in static and dynamic conditions. In static condition, the ink footprints with Clarke’s graphics were used for classification, and in dynamic condition, the Arch Index from Emed pedobarograph while walking was used for classification. When the type of the foot was based on Clarke’s graphics, no statistically significant differences were found. When the division was done according to the Arch Index, statistically significant differences between flat feet and normal feet groups were found for normalized gait speed, normalized cadence, pelvic rotation, ankle range of motion in sagittal plane, range of motion of foot progression, and two parameters of a vertical component of the ground reaction force: FZ2 (middle of stance phase) and FZ3 (push-off). Some statically flat feet function well during walking due to dynamic correction mechanisms.

The Prevalence and Factors Associated with Low Back Pain Among People with Flat Feet

Background

A positive relationship between flat feet and low back pain (LBP) has not gained consensus in literature. The aim of this study was to determine the prevalence and factors associated with low back pain (acute and chronic) among individuals with flat feet.

Methods

In 2018, a cross-sectional study was conducted at a national festival in Saudi Arabia, and 1798 adult visitors were invited to participate in face-to-face interviews. Participants' characteristics were stratified by the type of foot and they were questioned on acute low back pain (ALBP) or chronic low back pain (CLBP). The odds ratio (OR) were presented as a measure of this association, followed by a multivariate analysis.

Results

The prevalence of LBP among participants with flat feet was 65.9%, among whom 51.6% suffered ALBP and 48.4% suffered from CLBP. Flat feet increased the chances of having ALBP by 3.28 times and CLBP by 4.5 times. After stratification, ALBP and CLBP were both significantly higher among all participants with flat feet in comparison with their counter groups. Multivariate analyses showed that females were more likely to complain of ALBP. Participants who did no physical activity were more likely to complain of ALBP. Female participants and older participants were more likely to complain of ALBP and CLBP.

Conclusion

Flat feet are associated with both ALBP and CLBP. Significant factors of low back pain also included sex, age, occupation, and physical activity.

Extrinsic foot muscle forces and joint contact forces in flexible flatfoot adult with foot orthosis: A parametric study of tibialis posterior muscle weakness

BACKGROUND

The posterior tibialis tendon dysfunction (PTTD) is typically associated with progressive flatfoot deformity, which could be alleviated with foot orthosis. However, the evaluation of tibialis posterior (TP) weakness on lower limb mechanics of flatfoot adults with foot orthoses is scarce and requires further investigation.

RESEARCH QUESTION

This study aimed to examine the effects of TP weakness on lower limb mechanics in flatfoot adults with foot orthosis through gait analysis and musculoskeletal modelling.

METHODS

Fifteen young adults with flatfoot were recruited from University to perform a gait experiment with and without foot orthoses. Data collected from the motion capture system were used to drive the musculoskeletal modelling for the estimation of the joint force and extrinsic muscle forces of the lower limb. A parametric analysis was conducted by adjusting the TP muscle strength from 40 % to 100 %. Two-way repeated measures ANOVA was used to compare the peak extrinsic foot muscle forces and joint forces among different levels of TP weakness and insole conditions.

RESULTS

TP weakness significantly increased ankle joint force superoinferiorly (F = 125.9, p < 0.001) and decreased anteroposteriorly (F = 125.9, p < 0.001), in addition to a significant increase in the muscle forces of flexor hallucis longus (p < 0.001) and flexor digitorum longus (p < 0.001). Besides, the foot orthosis significantly reduced most peak muscle forces whilst significantly reduced the second peak knee force and peak ankle force compared to the control condition (F = 8.79-30.9, p < 0.05).

SIGNIFICANCE

The increased extrinsic foot muscle forces (flexor hallucis longus and flexor digitorum longus) and ankle joint forces in the TP weakness condition indicated that TP weakness may induce compensatory muscle activation and attenuated joint load. The abnormal muscle and joint mechanics in flatfoot adults with TP weakness might be restored by the orthosis.

Correlation between Different Methods to Diagnose Foot Posture Condition

Background: Authors refer to different methods to assess subjects’ foot posture. All methods present several limitations depending on the examiner or the chosen test. This study aims to investigate the relationship between different tests and Footprints parameters to diagnose subjects with a flat and neutral foot. Methods: The sample consisted of 37 participants, where 16 were included in the flatfoot group and 21 in the neutral foot group. Only subjects who presented a Navicular Drop Test value of >9 mm were included in the flatfooted group. All participants were submitted to Resting Calcaneal Stance Position and plantar pressure platform assessment for Footprints analysis. Associations between all tests and Footprints parameters were determined by Pearson’s correlation analysis. Results: Regarding both groups, significant correlations between tests were moderate to nearly perfect to identified both conditions of foot posture. All correlations were statistically significant (p < 0.05). Conclusions: The diagnosis accuracy of foot posture condition can be compromised depending on the used test. The Navicular Drop Test and the Resting Calcaneal Stance Position were shown to mislead foot posture condition assessment, unlike Footprints parameters that can be important evaluation tools in a clinical environment.

Assessment of the Foot's Longitudinal Arch by Different Indicators and Their Correlation with the Foot Loading Paradigm in School-Aged Children: A Cross Sectional Study

Background: There are numerous studies assessing the morphological structure of the foot, but there is a notable scarcity of those focused on juxtaposing various longitudinal arch indices with foot loading paradigm. The present study aimed to determine the overall reliability, diagnostic accuracy of respective variables, and their correlation with the foot loading paradigm. Methods: The study group consisted of 336 children, aged 10–15 years (girls 49.1% and boys 50.9%). The morphological structure of the plantar part of the foot in static conditions was assessed with the aid of a 2D podoscan. Individual foot loading paradigm in static conditions was assessed making use of the FreeMed platform. Results: Staheli (SI), Chippaux–Smirak (CSI), and Sztriter–Godunow (KY) indices were strongly correlated with each other (ρ > 0.84, p < 0.001). Own research corroborated an increased pressure of hollow feet, as assessed by the SI, CSI, and KY indices, on the forefoot and the hindfoot, foot zones B, E, F; these correlations being statistically significant. The results yielded by the present study also indicate an increased pressure on the metatarsal, and foot zones C, D of the flat feet. Conclusions: Flatfootedness is not believed to be a common deformity among children and adolescents. The SI, CSI, and KY indices were found to be strongly correlated, as well as proved reliable in assessing the foot’s longitudinal arch.

Quality of Life in Young Adults after Flatfoot Surgery: A Case-Control Study

The true impact of surgery for flatfoot deformities on patient's quality of life and health status remains poorly defined. The aim of this study is to evaluate the quality of life and the return to daily tasks and sports or physical activities in young adults after surgical correction of flatfoot deformity. Patients treated for bilateral symptomatic flat foot deformity were retrospectively studied. The healthy control group comprised a matched reference population with no history of foot surgery or trauma that was voluntary recruited from the hospital community. All subjects were asked to fill out questionnaires centered on the assessment of the health-related quality of life (Short-form 36; SF-36) and physical activity (International Physical Activity Questionnaire; IPAQ). Most study group SF-36 subscales were lower when compared to the control group. Among the study group, post-operatively, 36.6% of patients managed to resume low levels of sports activity, 40% were sufficiently active and were able to perform moderate sports activity (an activity that requires moderate physical effort and which forces the patient to breathe with a frequency only moderately higher than normal), while 23.3% of them were active or very active and were able to perform intense physical activity. Most IPAQ scores were statistically different from the control group. The present study suggests that patients treated with medializing calcaneal osteotomy and navicular-cuneiform arthrodesis for symptomatic flafoot had lower levels of quality of life and physical activity when compared to healthy subjects. After surgery, patients showed a significant improvement in the clinical scores.

Degree of Impact of Tailor's Bunion on Quality of Life: A Case-Control Study

Tailor’s bunion (TB) disease should be considered one of the foot injuries that causes disability in feet as well as general health. This case–control descriptive study investigated and contrasted the effects of different TB types in a sociodemographic population using the Foot Health Status Questionnaire (FHSQ). A sample of 100 subjects with a mean age of 51.70 ± 17.78 years was recruited and requested to reply to a foot health survey. Results were self-reported. Subjects were scored. Participants with TB type III (TB3) registered lower scores for foot pain, foot function, footwear, and foot health. Physical activity and social capacity had higher scores, and vigor and general health were lower. A Kruskal–Wallis test was used for systematic differences between the FHSQ and different TB types. In all analyses, statistical significance was considered a p-value <0.05 with a 95% confidence interval. Statistically significant differences were found between all domains of the FHSQ and TB, except for the social capacity domain and vigor. The FHSQ is an important measurement tool in TB subjects, showing that factors such as sex, age, and footwear used throughout an individual’s life are significantly associated with the development of TB3 and its influence on foot pain and foot health.

Congenital Unilateral Hypertrophy of the Plantar Musculature with Multiple Toe Deformities: A Case Report and Literature Review

Congenital unilateral hypertrophy of the plantar musculature is a rare condition, and to our knowledge, reports of only 14 cases have been previously published. As only one describes a concomitant orthopedic toe deformity, we report our case of abductor hallucis, flexor digitorum brevis, and abductor digiti minimi muscle hypertrophy in combination with hallux valgus and claw toe deformity as well as a laterally abducted fifth toe. Thus, this report presents the rare case of congenital hypertrophy of the plantar musculature associated with complex toe deformities. Moreover, the present article contains a detailed description of our surgical technique as well as a review of the current literature.

Locomotion Variations of Arch Index and Interlimb Symmetry in Shod and Barefoot Populations

The purpose of this study was to investigate the variations of arch index from static standing to dynamic walking and running; furthermore, the interlimb symmetry was checked in the two populations. A total of eighty male participants were recruited for this study, with forty habitually barefoot and forty habitually shod males, respectively. Arch index (AI) was calculated following the previously established “gold standard” measurement via contact areas recorded from EMED. Repeated measure analysis of variance (ANOVA) was employed to compare the difference between static and dynamic walking and running arch index. Paired-samples t-test and symmetry index (SI) were used to investigate the symmetry of the left foot arch index and right foot arch index. It was found that the dynamic arch index was significantly higher than the static arch index in barefoot and shod males, showing an increase from static weight-bearing standing to dynamic walking and running. However, interlimb (right-left) symmetry in the foot arch index was observed in the two populations. Dynamic changes of the arch index may provide implications that need to be considered while designing shoe lasts or insoles. Knowledge of the healthy arch index range reported from this study could also be used as a standard baseline to probe into foot and arch disorders.

Immediate Effects of Medially Posted Insoles on Lower Limb Joint Contact Forces in Adult Acquired Flatfoot: A Pilot Study

Flatfoot is linked to secondary lower limb joint problems, such as patellofemoral pain. This study aimed to investigate the influence of medial posting insoles on the joint mechanics of the lower extremity in adults with flatfoot. Gait analysis was performed on fifteen young adults with flatfoot under two conditions: walking with shoes and foot orthoses (WSFO), and walking with shoes (WS) in random order. The data collected by a vicon system were used to drive the musculoskeletal model to estimate the hip, patellofemoral, ankle, medial and lateral tibiofemoral joint contact forces. The joint contact forces in WSFO and WS conditions were compared. Compared to the WS group, the second peak patellofemoral contact force (p < 0.05) and the peak ankle contact force (p < 0.05) were significantly lower in the WSFO group by 10.2% and 6.8%, respectively. The foot orthosis significantly reduced the peak ankle eversion angle (p < 0.05) and ankle eversion moment (p < 0.05); however, the peak knee adduction moment increased (p < 0.05). The reduction in the patellofemoral joint force and ankle contact force could potentially inhibit flatfoot-induced lower limb joint problems, despite a greater knee adduction moment.

Association of Arch Stiffness with Plantar Impulse Distribution during Walking, Running, and Gait Termination

The purpose of this study was to determine relationships between arch stiffness and relative regional impulse during walking, running, and stopping. A total of 61 asymptomatic male subjects volunteered to participate in the study. All were classified by calculating the arch stiffness index using 3-dimensional foot morphological scanning. Plantar pressure distribution data were collected from participants using a Footscan pressure platform during gait tests that included walking, running, and gait termination. The stiff arches group (n = 19) and flexible arches group (n = 17) were included in the following data analysis. The results suggested that subjects with stiffer arches had a larger and smaller percentage of plantar impulse in the forefoot and rearfoot, respectively, than subjects with more flexible arches during walking and running. However, during gait termination, which included planned and unplanned gait stopping, the plantar impulse distribution pattern was found to be reversed. The current findings demonstrate that the distributional changes of plantar loading follow unidirectional transfer between the forefoot and the rearfoot on the plantar longitudinal axis. Moreover, the patterns of impulse distribution are also different based on different gait task mechanisms.

Relationships between Foot Morphology and Foot Muscle Strength in Healthy Adults

The purpose of this study was to investigate if measurements of foot morphology in sitting and standing positions can predict foot muscle strength. Twenty-six healthy male adults were recruited, and their foot morphology and foot muscle strength were measured. Foot morphological variables, toe flexor strength, and metatarsophalangeal joint flexor strength were measured by using a digital caliper, Ailitech-AFG500 dynameter and metatarsophalangeal joint flexor strength tester, respectively. Partial correlation and multivariate stepwise regression were used to explore the relationships between foot morphology and toe/metatarsophalangeal joint strength. Results adjusted by age and body mass index were as follows: (1) truncated foot length in sitting and standing positions and foot width in standing position were positively correlated with the flexor strength of the first toe; (2) foot length, foot width, and truncated foot length in both positions were positively related to the flexor strength of the other toes; (3) arch height index in sitting position and differences in navicular height were negatively associated with the flexor strength of the other toes; (4) differences in foot width were negatively associated with metatarsophalangeal joint flexor strength; and (5) the multivariate stepwise regression model showed that truncated foot length in sitting position, navicular height in standing position, differences in navicular height, foot width in sitting position, and differences in foot width were significantly correlated with toe/metatarsophalangeal joint flexor strength. Simple measurements of foot morphological characteristics can effectively predict foot muscle strength. Preliminary findings provided practical implications for the improvement of the foot ability by making specific foot muscle training sessions in professional sports and by compensating the predicted muscle strength defects to prevent foot injury.