Increasing midtarsal joint stiffness reduces triceps surae metabolic costs in walking simulations but has little effect on total stance limb metabolic cost.

The human foot's arch is thought to be beneficial for efficient gait. This study addresses the extent to which arch stiffness changes alter the metabolic energy requirements of human gait. Computational musculoskeletal simulations of steady state walking using direct collocation were performed. Across a range of foot arch stiffnesses, the metabolic cost of transport decreased by less than 1% with increasing foot arch stiffness. Increasing arch stiffness increased the metabolic efficiency of the triceps surae during push-off, but these changes were almost entirely offset by other muscle groups consuming more energy with increasing foot arch stiffness.

Acute effects of athletic taping on arch deformity and plantar pressure in young female adults with flexible flatfoot.

OBJECTIVE: This work aimed to explore the acute effects of athletic taping techniques on foot arch deformity and plantar pressure in young female adults with flexible flatfoot (FFT). METHODS: Twenty young female adults with FFT were recruited in the current study. Each participant was randomly divided into two taping groups, namely, augmented low-dye (ALD) and modified low-dye (MLD). The foot arch deformity and plantar pressure were measured at baseline, after taping and after 20 min of walking. The foot arch deformity was determined based on navicular drop distance (NDD) and resting calcaneal stance position (RCSP). RESULTS: Compared with baseline, the NDD values were significantly lower after taping. After 20 min of walking, ALD taping resulted in a lower NDD value than MLD (p < 0.001). ALD maintained a higher RCSP than baseline after 20 min of walking (p = 0.004). Furthermore, compared with baseline, medial midfoot force-time integration (p = 0.013) and contact area (p = 0.022) increased after taping with MLD, and peak pressure in the medial midfoot increased after walking for 20 min with MLD (p = 0.026). Peak pressure in the second to fifth toes significantly decreased after 20 min of walking with ALD compared with that after taping immediately (p = 0.002). CONCLUSIONS: ALD and MLD taping could improve FFT arch deformity and plantar pressure distribution, prospectively changing peak pressure of the second to fifth toe area and medial midfoot after 20 min of walking, integrated contact area and force-time integration medial midfoot during walking in young female adults. Furthermore, ALD taping could improve FFT deformity more than using MLD after 20 min of walking. Thus, when treating FFT in young female adults, ALD taping should be considered adaptively to guide arch support production and correct midfoot pronation.

Hindfoot and Foot Arch Reconstruction by Atypical Subtalar Arthrodesis and Achilles Tendon Lengthening for a Severe Comminuted Calcaneal Fracture: A Case Report.

Visual AbstractThis is a visual representation of the abstract.

Effects of plantar fascia stiffness on the internal mechanics of idiopathic pes cavus by finite element analysis: implications for metatarsalgia.

Metatarsalgia occurring in individuals with pes cavus is typically associated with abnormal loading patterns in the forefoot resulting from structural alterations. Simultaneously, the frequent overstress of the plantar fascia (PF) caused by the persistence of this foot deformity may further exacerbate the chronic pain induced by metatarsal overload. We aimed to investigate and quantify the effects of PF stiffness on the internal biomechanics of pes cavus using a computational modelling approach. A patient-specific finite element model of the foot-ankle complex using the actual three-dimensional geometry of idiopathic pes cavus bones and soft tissues was reconstructed. A sensitivity study was conducted to evaluate the effects of varying elastic modulus (0-700 MPa) of the PF on the metatarsal stress distribution, and force transmission through the metatarsophalangeal (MTP) and tarsometatarsal (TMT) joints in the pes cavus. The results indicated that variations in PF stiffness led to stress redistribution in the metatarsal region. Peak stress gradually reduced with decreasing stiffness until the PF was released, eventually resulting in a reduction of 22.39% compared to the reference value of 350 MPa. Furthermore, adjusting the PF stiffness to twice the reference value (700 MPa) increased the contact forces through the TMT and MTP joints by up to 23% and 116%, respectively. The reduction of PF stiffness alleviated focal metatarsal loading, and therefore, surgical fascia release can be considered to alleviate metatarsalgia in patients with pes cavus.

Evaluation of the activities of the intrinsic and extrinsic muscles of the foot during toe flexion with or without interphalangeal joint flexion using ultrasound shear wave elastography.

The intrinsic muscles of the foot are important to maintain the arch of the foot and to participate in sports activities. Using ultrasound shear wave elastography, we investigated the effect of different toe flexion methods on the activity of the intrinsic and extrinsic muscles of the foot. The study included 15 healthy adults who performed toe flexion under 2 conditions: with interphalangeal (IP) joint flexion and without IP joint flexion. The applied load during flexion was 500 g. Muscle stiffness was measured in the abductor hallucis, flexor hallucis brevis, flexor digitorum brevis, quadratus plantae, flexor hallucis longus, and flexor digitorum longus muscles using ultrasound shear wave elastography. Muscle stiffness was statistically compared with IP flexion and without IP flexion (P < 0.05). The stiffness of the abductor hallucis (P < 0.0005), flexor hallucis brevis (P = 0.022), and flexor digitorum brevis muscles (P < 0.0005) was significantly greater without IP flexion than with IP flexion. In contrast, the muscle stiffness of the flexor hallucis longus (P = 0.001) and the flexor digitorum longus (P = 0.004) was significantly greater during with IP flexion than without IP flexion. This study shows that the abductor hallucis, flexor hallucis brevis, flexor digitorum brevis muscles are more active during toe flexion without IP flexion. These results suggest that the toe flexion method is important for more effective training of the intrinsic muscles of the foot.

Characterizing the mechanical function of the foot's arch across steady-state gait modes.

The arch of the human foot has historically been likened to either a truss, a rigid lever, or a spring. Growing evidence indicates that energy is stored, generated, and dissipated actively by structures crossing the arch, suggesting that the arch can further function in a motor- or spring-like manner. In the present study, participants walked, ran with a rearfoot strike pattern, and ran with a non-rearfoot strike pattern overground while foot segment motions and ground reaction forces were recorded. To quantify the midtarsal joint's (i.e., arch's) mechanical behavior, a brake-spring-motor index was defined as the ratio between midtarsal joint net work and the total magnitude of joint work. This index was statistically significantly different between each gait condition. Index values decreased from walking to rearfoot strike running to non-rearfoot strike running, indicating that the midtarsal joint was most motor-like when walking and most spring-like in non-rearfoot running. The mean magnitude of elastic strain energy stored in the plantar aponeurosis mirrored the increase in spring-like arch function from walking to non-rearfoot strike running. However, the behavior of the plantar aponeurosis could not account for a more motor-like arch in walking and rearfoot strike running, given the lack of main effect of gait condition on the ratio between net work and total work performed by force in the plantar aponeurosis about the midtarsal joint. Instead, the muscles of the foot are likely altering the motor-like mechanical function of the foot's arch, the operation of these muscles between gait conditions warrants further investigation.

High rate of complications after corrective midfoot/subtalar arthrodesis and Achilles tendon lengthening in Charcot arthropathy type Sanders 2 and 3.

PURPOSE: Corrective midfoot resection arthrodesis is the standard treatment of Charcot arthropathy type Sanders 2 and 3 with severe dislocation. In order to critically evaluate the effect of surgical correction, a retrospective analysis of our patient cohort was performed. Hereby, special emphasis was set on the analysis of the pre- and post-operative equinus position of the hindfoot. METHODS: Retrospectively, all patients (n = 82) after midfoot resection arthrodesis in Charcot type Sanders 2 or 3 were included. Complications were recorded, and the mean complication-free interval was calculated. Additionally, the calcaneal pitch as well as Meary's angle were measured pre- and post-operatively and in case of complications. RESULTS: Overall complication rate was 89%. Revision surgery was necessary in 46% of all patients. The mean complication-free interval was 285 days (0-1560 days). Calcaneal pitch and Meary's angle significantly improved after operation but returned to pre-operative values after onset of complications. Achilles tendon lengthening showed no significant effects on the mean complication-free interval. CONCLUSION: Operative treatment of Charcot arthropathy remains a surgical challenge with high complication rates. Surgical correction of equinus position has been highlighted for successful treatment but was not able to prevent complications in this study, which is demonstrated by the recurrent decrease of the calcaneal pitch in cases of reoperation. Therefore, as a conclusion of our results, our treatment algorithm changed towards primarily addressing the equinus malpositioning of the hindfoot by corrective arthrodesis of the hindfoot.

Assessment of foot arch shape and health status of adult population from Eastern Slovakia.

BACKGROUND: The purpose of this study was to determine the foot arch shape and the associated health status in a selected sample of individuals belonging to the adult majority population of eastern Slovakia and to evaluate which of the observed factors are involved in the occurrence and development of foot arch abnormalities. METHODS: The weight and height of probands were measured according to standard anthropometric methods using a personal scale and an anthropometer. The BMI index was calculated for each proband from the measured data. A Pod4Foot Classic podoscope was used to obtain the plantograms. The Chippaux-Smirak index method was used to evaluate the plantograms. The study includes a questionnaire containing questions about factors affecting the foot arch shape. RESULTS: The arch of the right foot was supported by the effect of wearing shoes at home (p = 0.013). There was an association between wearing high-heeled shoes and foot arch disorder, both on the right (p = 0.011) and left (p = 0.045) foot. There was no significant relationship between the prevalence of overweight or obesity, between wearing orthopaedic insoles in shoes without a prescription, wearing orthopaedic footwear at home, between sport or static and active work and foot arch disorder in our study. CONCLUSIONS: Most of the probands had a bilaterally normal arched foot, which is a positive result. Nowadays, there are a large number of orthopaedic devices on the market that help to shape the arch of the foot properly, but it is not correct to use these devices arbitrarily, without a doctor's prescription and a diagnosis of foot arch deviation.

Agreement between clinical measures to classify foot posture in asymptomatic adults.

BACKGROUND: Various clinical measures of static foot posture have been developed and used. However, consensus among clinical measures to classify foot posture remains to be established. Therefore, this study aimed to determine the level of agreement as a reliability component between two common clinical methods in asymptomatic adults: the normalised navicular height truncated (NNHt) and the Foot Posture Index-6 (FPI-6). METHODS: The NNHt and FPI-6 were conducted on 102 asymptomatic adults. The measurement sequence was randomly arranged for each participant. Weighted Kappa (Kw) was used to determine the agreement between the methods. RESULTS: Both the NNHt and FPI-6 achieved similar foot posture distributions: approximately 40-50% of the participants had a normal foot, approximately 40% had a pronated foot and approximately 10-20% had a supinated foot. The agreement between the methods to classify foot posture was excellent (Kw = 0.84). CONCLUSIONS: The present study found excellent agreement between two commonly used clinical measures. This finding highlights the NNHt and FPI-6 consensus for foot posture classification in asymptomatic adults.

Associations of muscle volume of individual human plantar intrinsic foot muscles with morphological profiles of the foot.

Human plantar intrinsic foot muscles consist of 10 muscles that originate and insert within the sole of the foot. It is known that the anatomical cross-sectional area (ACSA) and muscle thickness of two plantar intrinsic foot muscles, the flexor hallucis brevis (FHB) and abductor hallucis (ABH), associate with morphological parameters of the foot, such as total and truncated foot length and navicular height. However, it is unclear how the size for each of the plantar intrinsic foot muscles associates with various morphological profiles of the foot. This study aimed to elucidate this subject. By using magnetic resonance imaging (MRI), serial images of the right foot were obtained in 13 young adult men without foot deformities. From the obtained MR images, ACSA for each of the individual plantar intrinsic foot muscles was analyzed along the foot length, and then its muscle volume (MV) was calculated. The analyzed muscles were the abductor digiti minimi (ABDM), ABH, adductor hallucis oblique head (ADDH-OH), adductor hallucis transverse head (ADDH-TH), flexor digitorum brevis (FDB), FHB, and quadratus plantae (QP). Furthermore, MV of the whole plantar intrinsic foot muscle (WHOLE) was defined as the total MVs of all the analyzed muscles. As morphological parameters, total foot length, truncated foot length, forefoot width, ball circumference, instep circumference, navicular height, great toe eversion angle, and little toe inversion angle were measured using a laser three-dimensional foot scanner in standing and sitting conditions. In addition, navicular drop (ND) and normalized truncated navicular height (NTNH) were also calculated as medial longitudinal arch (MLA) height indices. The MV of WHOLE was significantly associated with the forefoot width, ball circumference, and instep circumference (r = 0.647-0.711, p = 0.006-0.013). Positive correlations were found between the forefoot width and MV of FHB, FDB, and QP (r = 0.564-0.653, p = 0.015-0.045), between the ball circumference and MV of QP (r = 0.559, p = 0.047), between the instep circumference and MV of FHB (r = 0.609, p = 0.027), and between the little toe inversion angle and MV of QP (r = 0.570, p = 0.042). The MVs of ABH, ABDM, and ADDH-OH were not significantly correlated with any morphological parameters of the foot. Similarly, no significant correlations were found between MV of each muscle and either of the MLA height indices (ND and NTNH). Thus, the current results indicate that forefoot width and circumferential parameters (instep and ball circumference), not MLA height, associate with the size of the whole plantar intrinsic foot muscles, especially those specialized in toe flexion (FHB, FDB, and QP).

Foot Arch Changes after Endoscopic Plantar Fascia Release for Recalcitrant Plantar Fasciitis.

Introduction: Endoscopic plantar fascia release (EPFR) is a minimally invasive surgical intervention for recalcitrant plantar fasciitis. Its efficacy has been convincing but the in vivo effect on medial longitudinal foot arch and footprint has not been studied. Our objective is to evaluate the changes of foot posture using radiographs and footprints following endoscopic plantar fascia release in recalcitrant plantar fasciitis. Materials and methods: This prospective cohort involved patients with recalcitrant plantar fasciitis who failed six months of conservative treatment. Two-portal endoscopic release of not more than 50% of plantar fascia width was performed. Footprint and standard weight-bearing anteroposterior and lateral radiographs of the foot were taken pre-operatively and at 12 months post-surgery. Arch index, normalised navicular height truncated, calcaneal inclination angle, calcano-1st metatarsal angle, talonavicular coverage angle and talus-2nd metatarsal angle were measured. Results: Sixteen patients (18 feet) were reported. Patients' follow-up ranged from 14 to 31 months after surgery (mean±SD: 23.44±5.76). The increase of arch index, calcano-1st metatarsal angle and reduction of calcaneal inclination angle were found statistically significant (p<0.05). Two normal arch patients progressed to asymptomatic flat arch feet. Three complications were noted between three to nine months post-surgery, one with medial column and two with lateral column symptoms. Conclusion: There is evidence of reduction in medial longitudinal arch of the foot after EPFR. Although the reduction remains asymptomatic, post-operative complications related to changes in biomechanics of the foot can occur between three to nine months. Patients should be monitored at least for 12 months and longer for those who are symptomatic.

Midterm outcomes of midfoot and hindfoot arthrodesis with strut allograft for Müller-Weiss disease.

BACKGROUND: Müller-Weiss disease (MWD), a rare dysplastic disorder of the foot, is characterized by deformity, sclerosis, and fragmentation of the lateral part of navicular bone. Arthrodesis is the mainstay treatment for MWD. Generally, arthrodesis can be achieved through internal fixation with metallic implants, and morselized chip bone may be packed into the gap for better bone union. However, with this procedure, the original foot size is not maintained and support for the foot arch is not provided. Sequela of short foot, or flatfoot is commonly observed even though these complications of surgery had not been reported with cases of MWD treated by arthrodesis. Herein, we present a retrospective analysis of treating MWD through midfoot and hindfoot arthrodesis combined with strut allograft. METHODS: From August 2006 to June 2019, 20 patients with MWD (mean age, 59.6 years; range, 40-80 years) underwent midfoot and hindfoot arthrodesis with strut bone allograft and were followed for at least 24 months. The patients were able to ambulate and participate in rehabilitation programs 3 months postoperatively. RESULTS: The used four radiographic parameters (Meary's angle in anteroposterior and lateral view, talonavicular coverage angle, calcaneal pitch) demonstrated significant differences (P < .05) preoperatively and postoperatively, but those between the postoperative values and the values at the last follow-up session did not, indicating that strut allograft was able to maintain normal alignment. The mean American Orthopaedic Foot & Ankle Society Ankle-Hindfoot scores at 2 years postoperatively revealed significant improvement from baseline, from 60.2 to 84.2 (P < .05). The 12-item Short Form Health Survey scores also improved significantly (P < .05). All patients reported substantial pain relief and exhibited improved functional outcomes and gait patterns. CONCLUSIONS: For advanced-stage MWD, arthrodesis with a precisely shaped, size-matched strut allograft provided strong support for biomechanical alignment and enhanced functional performance.

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.

Determination of relationship between foot arch, hindfoot, and hallux motion using Oxford foot model: Comparison between walking and running.

BACKGROUND: The foot arch plays an important role in propulsion and shock absorption during walking and running; however, the relationship among the foot arch, metatarsal locking theory, and nature of the windlass mechanism (WM) remain unclear. RESEARCH QUESTION: What are the differences in the kinematic relationship between the foot arch, hindfoot, and hallux during walking and running? METHODS: Relative angles within the foot were measured in 18 healthy men using the Oxford foot model (OFM). Data for barefoot walking at a comfortable speed and rearfoot running at 2.0 m/s were collected. Angles of the forefoot relative to the hindfoot (OFM-arch), hallux relative to the forefoot (Hallux) on the sagittal plane, and hindfoot relative to the shank (Hindfoot) on three anatomical planes were obtained. The medial longitudinal arch (MLA) angle was calculated to verify that OFM-arch can substitute the MLA angle. Each parameter was subjected to cross-correlation analysis and Wilcoxon signed-rank tests to examine the relationship with OFM-arch and compare them during walking and running. RESULT: OFM-arch was similar to the conventional MLA projection angle in both trials (gait: 0.79, running: 0.96 p < 0.01). Synchronization of the OFM-arch and Hallux angles was higher in running than in walking (gait: -0.09, running: -0.75 p < 0.01). Hindfoot supination was unrelated to OFM-arch. Hindfoot angle on the transverse plane exhibited a moderate relationship with OFM-arch, indicating different correlations in walking and running (gait: 0.63, running: -0.68 p < 0.01). SIGNIFICANCE: The elevation of the foot arch due to hallux dorsiflexion differed during walking and running; hence, other factors besides WM (such as intrinsic muscles) may affect the foot arch elevation during running. The hindfoot in the frontal plane does not contribute to arch raising and foot stability during running; it features different relationships with OFM-arch during walking and running.

Do Arch Height and Arch Stiffness Relate to Physical Performance in Adult Men?

Foot arch plays an important role in bearing body weight, absorbing ground reaction forces and maintaining balance, and its structure and function are bound to have a profound effect on physical activities and sports. Arch height and arch stiffness are 2 factors that represent the structure and function of the arch. Therefore, the purpose of this study was to explore the associations of arch height and arch stiffness with physical performance. A total of 56 men (aged 49.00 ± 7.95 years, mean body mass index [BMI] 26.80 ± 3.75 kg/m2) participated in this study. A 3-dimensional laser scanner was employed to obtain foot structure information of each participant, from which the arch height index (AHI) and arch stiffness index (ASI) were computed. Physical performance measures including agility, power, and proprioception were tested in a random order. The results indicated that the stepping forward and backward and vertical jump that represent agility and force respectively were negatively and significantly associated with AHI (r = -0.27, p = .045; r = -0.35, p = .009). When adjusted for age and BMI, only height of vertical jump was found to be correlated significantly with AHI (r = -0.29, p = .040); while no significant relationships were observed between physical performance measures and ASI. Multivariate linear regression analysis showed that AHI, age, and BMI can effectively predict the height of vertical jump. This study demonstrates that there is a negative correlation between arch height and muscle power of lower limbs in adult men.

Midfoot passive stiffness affects foot and ankle kinematics and kinetics during the propulsive phase of walking.

The midfoot joint complex (MFJC) is related to the mechanics and efficiency of the walking propulsive phase and low midfoot passive stiffness may require compensatory foot and ankle joint moments to avoid excessive pronation and inefficient propulsion. This study aimed to investigate the kinematics and kinetics of the MFJC and ankle during the propulsive phase of walking in subjects with larger and smaller midfoot passive stiffness. MFJC passive stiffness of 20 healthy adult participants, and the kinematics and kinetics of the MFJC (forefoot-rearfoot) and ankle (rearfoot-shank) during the stance phase of walking were measured. The participants were divided equally into two groups according to the MFJC passive stiffness. Ranges of motion (ROM) and mean joint moments were computed for the late stance. Independent t-tests (α = 0.05) revealed that subjects with lower midfoot passive stiffness showed an increased MFJC sagittal ROM (flattened longitudinal arch) (p = 0.002), increased ankle frontal ROM (more everted positions) (p = 0.002), increased MFJC frontal ROM (more inverted positions) (p = 0.019), as well as a tendency for larger ankle sagittal ROM (p = 0.056). They also showed increased MFJC (p = 0.021) and ankle (p = 0.018) moments in the sagittal plane, increased MFJC moment in the frontal plane (p = 0.047) and a tendency for a predominant ankle moment in the frontal (p = 0.058). Foot and ankle joint moments are possible strategies to reduce pronation and improve propulsion, but not sufficient to prevent the altered kinematics related to low midfoot stiffness. Therefore, midfoot passive stiffness is critical for foot and ankle kinematics and kinetics during walking propulsive phase and is a potential target of interventions.

The extensibility of the plantar fascia influences the windlass mechanism during human running.

The arch of the human foot is unique among hominins as it is compliant at ground contact but sufficiently stiff to enable push-off. These behaviours are partly facilitated by the ligamentous plantar fascia whose role is central to two mechanisms. The ideal windlass mechanism assumes that the plantar fascia has a nearly constant length to directly couple toe dorsiflexion with a change in arch shape. However, the plantar fascia also stretches and then shortens throughout gait as the arch-spring stores and releases elastic energy. We aimed to understand how the extensible plantar fascia could behave as an ideal windlass when it has been shown to strain throughout gait, potentially compromising the one-to-one coupling between toe arc length and arch length. We measured foot bone motion and plantar fascia elongation using high-speed X-ray during running. We discovered that toe plantarflexion delays plantar fascia stretching at foot strike, which probably modifies the distribution of the load through other arch tissues. Through a pure windlass effect in propulsion, a quasi-isometric plantar fascia's shortening is delayed to later in stance. The plantar fascia then shortens concurrently to the windlass mechanism, likely enhancing arch recoil at push-off.

Anthropometric Assessment Of Paediatric Flat Foot: A Diagnostic Accuracy Study.

BACKGROUND: Flat-foot involves total collapse of medial longitudinal arch, which becomes distressful when children begin to stand on their feet. Flat foot is usually diagnosed on clinical examination, however due to lack of a standardized protocol, there are conflicting views regarding its management. The objective of this study is to determine the accuracy of radiographic and podometric measurements in diagnosing paediatric flat foot. METHODS: It was a cross sectional diagnostic accuracy study. Eighty-four children of preschool and school going age were recruited equally into control and flat foot groups. Each child was examined clinically and was further classified into having flexible or rigid flat foot. For radiographic assessment, lateral and anteroposterior foot radiographs were taken while footprints were captured using podoscope and analysed with FREESTEP software. The diagnostic accuracy and correlation among different parameters were also computed. RESULTS: Clinically, of the 42 children in the flat foot group, 26 had flexible while 16 had rigid flat foot. Of these, 40 children were flat footed on one or more radiographic parameters, while 36 had podometric measurements within the flat foot range. Radiography had the sensitivity and specificity of 95% and 69%, respectively, while podometry was 86% sensitive and 47% specific. Clark's angle had highest sensitivity of 90%, with AUC of 0.952. A strong positive correlation was found between arch index and talocalcaneal angle (r=.805). CONCLUSIONS: The diagnostic accuracy of radiography was more than podometry. More specific and sensitive parameters in combination with clinical assessment may prove to be useful in the management of paediatric flat foot.

The relation of foot morphology to performance in three vertical jumping tasks / Relación entre la morfología del pie y el rendimiento en tres saltos verticales

SUMMARY: The objective of this research is to relate the performance in three vertical jump events with morphological variables of the foot and stature. A total of 177 practitioners of 12 sporting events aged 24.5 ±8.0 years, with 71.01 ±13.00 kg of body mass, 1.71±0.09 m height, and BMI of 24.29±3.24 kg·m-2 were evaluated with an anthropometer in terms of foot length (FL), forefoot width (FW), navicular height (NH), and hindfoot width (HW). These variables were normalized to the height of the subjects. From the footprint record the arch index (AI) was obtained, which indicates the morphology of the medial longitudinal foot arch (MLFA). Performance was evaluated in three vertical jump events: countermovement jump (CMJ), squat jump (SJ), and drop jump (DJ), recording the height reached. FL, FW and HW show a weak positive correlation (r<0.4; p<0.05) with the heights achieved in the three types of jump. The stature is strongly associated with FL, FW and HW (r=0.8; r=0.7 and r=0.6; respectively; p<0.05) and with the height in CMJ, SJ, and DJ (r=0.37; r=0.41 and r=0.32, respectively, p<0.05). The only normalized morphological foot variable that maintained consistency in the correlations analysis was the normalized foot length (NFL) with CMJ (r = 0.2, p<0,05). The subjects whose left foot length was equivalent to 14 % of the stature jumped 27.94 ±6.63 cm, those with 15 % jumped 30.96 ±7.4 cm, and those with 16 % jumped 31.03 ±7.8 cm. FL, FW, HW, and stature are moderately correlated with performance in vertical jump events. However, after discarding the stature of the subjects, only the foot length maintained its relation with performance in CMJ.

RESUMEN: El objetivo de esta investigación fue relacionar el rendimiento en salto vertical con variables morfológicas del pie y estatura. 177 practicantes de 12 disciplinas deportivas de 24,5 ±8,0 años; 71,01 ±13,00 kg; 1,71 ±0,09 m, e IMC de 24,29 ±3,24 kg•m-2 fueron evaluados con un antropómetro obteniendo longitud de pie (FL), ancho de antepié (FW), altura navicular (NH) y ancho de retropié (HW). Estas variables fueron normalizadas a la estatura. Se midió la huella plantar obteniendo el índice del arco (AI), el cual indica la morfología del arco plantar longitudinal medial (MLFA). El rendimiento fue evaluado en tres pruebas de salto: salto con contramovimiento (CMJ), sentadilla con salto (SJ) y salto desde caída (DJ), registrando la altura alcanzada. FL, FW y HW mostraron una débil correlación positiva (r<0,4; p<0,05) con la altura alcanzada en los tres saltos. La estatura se asocia con FL, FW y HW (r=0,8; r=0,7 y r=0,6; respectivamente; p<0,05) y con la altura en CMJ, SJ y DJ (r=0,37; r=0,41 y r=0,32, respectivamente, p<0,05). La única variable normalizada del pie que mantuvo consistencia en el análisis de correlaciones fue la longitud del pie normalizada (NFL) con CMJ (r=0,2; p<0,05). Los sujetos cuyo pie tiene una longitud equivalente al 14 % de la estatura saltaron 27,94 ±6,63 cm, los que equivalen al 15 % saltaron 30,96 ±7,4 cm y quienes tuvieron un pie equivalente a un 16 % de la estatura saltaron 31,03 ±7,8 cm. FL, FW, HW y la estatura se correlacionan moderadamente con el rendimiento en salto vertical. Sin embargo, después de descartar la estatura de los sujetos, solamente la longitud del pie mantiene su relación con el rendimiento en CMJ.

A New Automatic Foot Arch Index Measurement Method Based on a Flexible Membrane Pressure Sensor.

The foot arch index is an important index to evaluate the health of human feet and the biomechanics line, aiming at addressing the shortcomings of the low efficiency and slow speed of manual foot arch index measurement; in this work, an automatic foot arch index measurement method based on a flexible membrane pressure sensor was proposed. The distribution of plantar pressure data was obtained from the flexible membrane pressure sensor and converted into a digital image. The 8-neighborhood correlation pixel method was proposed to remove the interference of isolated noise points. In order to remove the toes' data without affecting the foot sole data, the row element association algorithm was proposed. The front and back endpoints of the foot were automatically located to obtain the foot length, and the foot arch index was also automatically obtained based on the foot arch pressure area. Whether it was a high arch foot, flat foot or normal foot, the method proposed in this paper could accurately and quickly distinguish them. The prototype was developed, and its feasibility and validity were verified by a series of tests.