Medial Longitudinal Arch Angle Research Articles

Effects of Neuromuscular Electrical Stimulation with Gastrocnemius Strengthening on Foot Morphology in Stroke Patients: A Randomized Controlled Trial.

This study aimed to investigate the effects of neuromuscular electrical stimulation (NMES) with gastrocnemius (GCM) strength exercise on foot morphology in patients with stroke. Herein, 31 patients with chronic stroke meeting the study criteria were enrolled and divided into two groups; 16 patients were randomized to the gastrocnemius neuromuscular electrical stimulation (GCMNMES) group, and 15 patients to the conventional neuromuscular electrical stimulation (CNMES) group. The GCMNMES group conducted GCM-strengthening exercise with NMES. CNMES group conducted NMES at paretic tibialis anterior muscle with ankle dorsiflexion movement. These patients underwent therapeutic interventions lasting 30 min/session, five times a week for 4 weeks. To analyze changes in foot morphology, 3D foot scanning was used, while a foot-pressure measurement device was used to evaluate foot pressure and weight-bearing area. In an intra-group comparison of 3D-foot-scanning results, the experimental group showed significant changes in longitudinal arch angle (p < 0.05), medial longitudinal arch angle (MLAA) (p < 0.01), transverse arch angle (TAA) (p < 0.01), rearfoot angle (RA) (p < 0.05), foot length (FL) (p < 0.05), foot width (FW) (p < 0.05), and arch height index (AHI) (p < 0.01) of the paretic side and in TAA (p < 0.05) and AHI (p < 0.05) of the non-paretic side. The CNMES group showed significant changes in TAA (p < 0.05) and FW (p < 0.05) of the paretic side and TAA (p < 0.05) and AHI (p < 0.05) of the non-paretic side. An inter-group comparison showed significant differences in MLAA (p < 0.05) and RA (p < 0.05) of the paretic side. In an intra-group comparison of foot pressure assessment, the experimental group showed significant differences in footprint area (FPA) (p < 0.05) of the paretic side and FPA symmetry (p < 0.05). The CNMES group showed a significant difference in only FPA symmetry (p < 0.05). An inter-group comparison showed no significant difference between the two groups (p < 0.05). Thus, NMES with GCM-strengthening exercises yielded positive effects on foot morphology in patients with stroke.

Mid-term assessment of subtalar arthroereisis with Talar-Fit implant in pediatric patients with flexible flatfoot and comparing the difference between different sizes and exploring the position of the inserted implant.

Subtalar arthroereisis (STA) has gained growing acceptance as a viable approach solution for the management of pediatric flexible flatfoot. However, STA still remains controversial. The purpose of this study is to assess the effect of STA using the Talar-Fit implant for treating pediatric flexible flatfoot. Specifically, the aims of the study are as follows: first, to present the mid-term outcomes of STA using the Talar-Fit implant; second, to compare the radiographic and clinical outcomes associated with varying sizes of Talar-Fit implant; and third, to analyze the optimal position of the inserted implants. A retrospective analysis was conducted on a cohort of 57 pediatric patients diagnosed with flexible flatfoot (77 feet) who underwent STA utilizing Talar-Fit between January 2014 and December 2021. The participants were categorized into five groups according to the size of the implant: Group 8, Group 9, Group 10, Group 11, and Group 12. The evaluation included the assessment of clinical function using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hind foot score, as well as the assessment of radiographic data such as the calcaneal pitch angle (CPA), lateral Meary angle (LMA), talar declination angle (TDA), and medial longitudinal arch angle (MLAA) were evaluated. Furthermore, the position of the inserted implants was also recorded, including angle, depth, and distance. The comparison of pre- and postoperation was conducted using the paired Student's t-test, whereas the analysis of differences among subgroups was performed using the Wilcoxon rank-sum test. A P-value < 0.05 is considered statistically significant. In total, 57 pediatric patients (77 feet) were successfully followed-up for an average period of 26.8 months. The overall AOFAS score significantly improved from 58.6 ± 10.9 to 85.2 ± 8.6 (P < 0.001). Furthermore, the LMA decreased from 20.3° ± 3.6° to 4.5° ± 1.3°, the CPA increased from 14.8° ± 1.6° to 23.6° ± 2.7°(P < 0.05), the TDA decreased from 40.2° ± 2.3° to 25.5° ± 3.2°(P < 0.05), and the MLAA decreased from 140.1° ± 2.8° to 121.4° ± 3.9°(P < 0.05). No statistically significant differences were observed among subgroups regarding the final outcomes. The improvements of CPA, TDA, and MLAA among different groups were significantly different; however, the adjusted P-values were all greater than 0.05. The implant were inserted at a mean angle of 89.5° ± 2.4°, a mean depth of 0.9 mm ± 2.1 mm, and a mean distance of 9.9 mm ± 0.9 mm. Eight patients experienced complications, including six cases of pain occurrence and two cases of implant dislocation. STA with Talar-Fit has demonstrated satisfactory mid-term outcomes. A Talar-Fit with a larger size may demonstrate a superior effect when compared with that of a smaller size. The implants were inserted in a similar position, indicating that the medial edge of the implant may be possible to transcend the midline of the talus neck.

Using surface markers to describe the kinematics of the medial longitudinal arch

BackgroundStatic and dynamic assessment of the medial longitudinal arch (MLA) is an essential aspect for measuring foot function in both clinical and research fields. Despite this, most multi-segment foot models lack the ability to directly track the MLA. This study aimed to assess various methods of MLA assessment, through motion capture of surface markers on the foot during various activities. MethodsThirty general population participants (mean age 20 years) without morphological alterations to their feet underwent gait analysis. Eight measures, each representing a unique definition of the MLA angle using either real only, or both real and floor-projected markers, were created. Participants performed tasks including standing, sitting, heel lift, Jack’s test and walking, and had their Arch Height Index (AHI) measured using callipers. Multiple-criteria decision analysis (MCDA) with 10 criteria was utilised for selecting the optimal measure for dynamic and static MLA assessment. ResultsIn static tasks, the standing MLA angle was significantly greater in all measures but one when compared to sitting, Jack’s test and heel lift. The MLA angle in Jack’s test was significantly greater than in heel lift in all measures. Across the compared dynamic tasks, significant differences were noted in all measures except one for foot strike in comparison to 50% gait cycle. All MLA measures held significant inverse correlations with MLA measured from static and dynamic tasks. Based on MCDA criteria, a measure comprising the first metatarsal head, fifth metatarsal base, navicular and heel markers was deemed the best for MLA assessment. SignificanceThis study aligns with the current literature recommendations for the use of a navicular marker for characterising the MLA. It contrasts with previous recommendations and advocates against the use of projected markers in most situations.

Clinical and multi-segment kinematic analysis of a modified Grice arthrodesis to correct type II adult-acquired flat-foot

BackgroundAdult acquired flat foot (AAFF) is a symptomatic postural alteration of the foot due to modifications in bony structures and/or soft tissues supporting the medial longitudinal arch. For the most severe cases, when orthotic solutions do not provide enough pain relief, surgery may be necessary. Research questionIs it possible to restore a normal medial longitudinal arch and to correct the static and dynamic frontal plane alignment of the rearfoot via a modified Grice surgical procedure in AAFF patients? MethodsEleven patients with stage II AAFF were recruited in the study and underwent the Grice procedure. Patients were assessed via gait analysis using a validated multi-segment foot protocol. Double-leg standing static posture and foot joint kinematics during barefoot walking were measured before surgery and at a mean follow-up of 15 ± 8 months. Twenty-seven age-matched healthy subjects without foot morphological alterations were used as control. Patients’ feet were clinically assessed via the Foot Function Index and the Foot Posture Index. Wilcoxon signed rank test was used to assess differences in kinematic and spatio-temporal parameters between pre-op and follow-up evaluations. 1D statistical parametric mapping was used to assess differences in temporal profiles of foot joint rotations. ResultsThe clinical indexes significantly improved at post-op (p < 0.05). No differences in sagittal plane static and dynamic joint rotations were observed between pre-op and post-op. In the frontal plane, metatarsus to calcaneus and midfoot to calcaneus rotation angles significantly improved from pre-op to post-op, with the latter resulting consistent with control data. Range of motion and maximum value of the medial longitudinal arch angle were reduced following surgery. SignificanceThe modified Grice procedure restored a good frontal-plane alignment of rearfoot and midfoot, and the clinical scores provided evidence of its effectiveness in significantly reducing pain and improving the quality of daily activities.

EXERCISES AND NEUROMUSCULAR ELECTRIC STIMULATION FOR MEDIAL LONGITUDINAL ARCH: CLINICAL TRIAL.

The extrinsic muscles, such as the posterior tibialis and long flexor of the hallux and the intrinsic of the foot, are part of the active subsystem of the central system of the foot and play an essential role in the control of the medial longitudinal arch resulting from difficulty in contracting the muscle, neuromuscular electrostimulation (NMES) becomes a resource combined with strengthening and recommended for rehabilitation. T this work aims to evaluate the effectiveness of NMES associated with exercise in deforming the medial longitudinal arch. This is a randomized blind clinical trial. 60 asymptomatic participants were divided into three groups: NMES, exercise and control. The NMES and exercise group performed seven exercises for the intrinsic and extrinsic muscles twice a week for 6 weeks, and the NMES group used an NMES associated with five exercises. Navicular height and medial longitudinal arch angle were taken before and after the intervention period. No statistically significant differences existed between groups for navicular height and medial longitudinal arch angle. NMES associated with exercise does not change the characteristics of the medial longitudinal arch in association with asymptomatic. Level of Evidence I; Randomized clinical trial.

Effects of Barefoot and Shod on the In Vivo Kinematics of Medial Longitudinal Arch During Running Based on a High-Speed Dual Fluoroscopic Imaging System.

Shoes affect the biomechanical properties of the medial longitudinal arch (MLA) and further influence the foot’s overall function. Most previous studies on the MLA were based on traditional skin-marker motion capture, and the observation of real foot motion inside the shoes is difficult. Thus, the effect of shoe parameters on the natural MLA movement during running remains in question. Therefore, this study aimed to investigate the differences in the MLA’s kinematics between shod and barefoot running by using a high-speed dual fluoroscopic imaging system (DFIS). Fifteen healthy habitual rearfoot runners were recruited. All participants ran at a speed of 3 m/s ± 5% along with an elevated runway in barefoot and shod conditions. High-speed DFIS was used to acquire the radiographic images of MLA movements in the whole stance phase, and the kinematics of the MLA were calculated. Paired sample t-tests were used to compare the kinematic characteristics of the MLA during the stance phase between shod and barefoot conditions. Compared with barefoot, shoe-wearing showed significant changes (p < 0.05) as follows: 1) the first metatarsal moved with less lateral direction at 80%, less anterior translation at 20%, and less superiority at 10–70% of the stance phase; 2) the first metatarsal moved with less inversion amounting to 20–60%, less dorsiflexion at 0–10% of the stance phase; 3) the inversion/eversion range of motion (ROM) of the first metatarsal relative to calcaneus was reduced; 4) the MLA angles at 0–70% of the stance phase were reduced; 5) the maximum MLA angle and MLA angle ROM were reduced in the shod condition. Based on high-speed DFIS, the above results indicated that shoe-wearing limited the movement of MLA, especially reducing the MLA angles, suggesting that shoes restricted the compression and recoil of the MLA, which further affected the spring-like function of the MLA.

Effect of Arch Height Flexibility in Individuals With Flatfoot on Abductor Hallucis Muscle Activity and Medial Longitudinal Arch Angle During Short Foot Exercises

Flatfoot presents decreased medial longitudinal arch (MLA), and such foot deformity involves intrinsic foot muscles dysfunction. Flatfoot can be classified into flexible and stiff types according to arch height flexibility (AHF). Short foot exercise (SFE) is an intrinsic foot muscle strengthening exercise, which is reportedly effective against flatfoot. However, its effectiveness against flexible or stiff types in flatfoot is unclear. We examined the effect of AHF in individuals with flatfoot during abductor hallucis muscle (AbH) activity and medial longitudinal arch during SFE. Foot alignment was assessed using the arch height index during standing, and individuals with flatfoot (N=16) were recruited. The AbH activity and MLA angle during SFE while maintaining single-leg standing were assessed. The relationship between AHF and AbH activity and between AHF and MLA angle ratio was analyzed using correlation coefficients. Additional correlations between AHF and AbH activity were observed with the outliers removed. There were no correlations between AHF and AbH muscle activity and between AHF and MLA angle ratio. However, with the 2 outliers removed, moderate correlations between AHF and AbH activity were significant (r=0.64, p = .01). AbH activity during SFE increased in individuals with flatfoot for high AHF (flexible type). Thus, SFE may be more effective for individuals with flatfoot having a high AHF. These findings may be helpful when making decisions for surgery and rehabilitation.

Interobserver Reliability in the Radiological Evaluation of Flatfoot (Pes Planus) Deformity: A Cross-Sectional Study

This study was planned for analyzing the interobserver reliability on the diagnosis of flatfoot. This study aims to evaluate the interobserver reliability of the digital radiography of flatfoot patients. Eight parameters were used in digital x-rays within the as statistically in 2 groups. Study group includes 34 patients. Two groups were formed four medical specialists as 2 orthopedists and 2 radiologists. Two orthopedists made measurements on x-ray viewing as calcaneal pitch (CP) as CP floor, calcaneus-1 metatarsal angle, calcaneus-5 metatarsal angle; longitudinal arch angles (LAAs) as medial and lateral LAAs, Tomeno-Meary angle (TMA), anteroposterior and lateral CYMA line. The intraclass correlation coefficient (ICC) analysis was performed. Fleiss Kappa and Kappa was used to investigate the reliability of qualitative data between 2 observers. ICCs were in high levels for CP floor, calcaneus-1 metatarsal angle, calcaneus-5 metatarsal angle. ICCs of TMA was in high levels, also. ICCs of LAA-medial and LAA-lateral were not in high levels as other measurements. In the CYMA line (anteroposterior and lateral) Kappa was 0.140 for right feet in the quadruple group (p = .045; .458; and .314). Kappa was 0.197 for left feet in the quadruple group (p = .005; .146; .377). The ICCs was excellent for CP angles and TMA in all groups. LAAs as medial and lateral longitudinal arch angle had not high ICC's. CYMA line had significant p values in the quadruple group. But not in orthopedists and radiologists.

Prevalence of Flat Foot in College Going Students: A Cross Sectional Study

Background: A healthy foot is vital for good posture and ambulation. Flatfoot or pes planus is a medical condition defined by the absence or lowered medial longitudinal arch, with Osseo-ligamentous misalignment. The objective of this study was to find out the prevalence of flat foot in college-going students aged between 18 to 25 years by using navicular drop and medial longitudinal arch angle assessment methods. Methods: In this cross-sectional study, 205 volunteers (116 male and 89 female) were assessed for flat foot using Brody’s navicular drop test and medial longitudinal arch angle measurement with an age range of 18-25 years. The navicular drop of ≥ 10mm and medial longitudinal arch angle of &lt; 130° were considered flat feet. Results: The mean age of the total population (n=205) was 23.30 ± 1.63 years. The result of this study showed that when we used the ND test, there was a prevalence of flat foot in 20% of the total population (for males: 21.55%; for females: 17.97%) whereas when we used MLAA measurement, there was the prevalence of 5.36% in total population (for males: 5.17%; for females: 5.61%). Conclusion: The results of this study quantified the prevalence of flat foot in young college-going students. It can be concluded from the result of this study that the prevalence of flat foot in college-going students was 20% when using the navicular drop test whereas 5.61% when using medial longitudinal arch angle measurement.

Effect of Peroneus Longus Muscle Release on Abductor Hallucis Muscle Activity and Medial Longitudinal Arch before Toe-Tap Exercise in Participants with Flexible Pes Planus.

Pes planus is a medical condition of the foot wherein there is a flattening or lowering of the medial longitudinal arch. The abductor hallucis muscle starts at the heel bone and attaches to the medial side of the first toe. Whenever it contracts, it plays a key role in elevating the medial longitudinal arch. Hence, the abductor hallucis muscle should be strong enough to control the depression on the medial longitudinal arch. The peroneus longus muscle plantarflexes the ankle and everts the ankle and subtalar joint. If this muscle contracts more than the abductor hallucis muscle does, the medial longitudinal arch of the foot is depressed. This study aimed to investigate the effect of myofascial release of the peroneus longus before performing the toe-tap exercise for strengthening the abductor hallucis muscle in participants with flexible pes planus. This cross-over study included 16 volunteers with flexible pes planus. The participants performed a toe-tap exercise before and after the myofascial release of the peroneus longus. During the toe-tap exercise, the muscle activity of the abductor hallucis and peroneus longus were measured using a Delsys Trigno Wireless Electromyography System. The angle of the medial longitudinal arch was measured using Image J software. Photos in the sagittal plane were used. The peroneus longus activity and medial longitudinal arch angles were significantly decreased. On the other hand, the activity of the abductor hallucis significantly increased after the myofascial release of the peroneus longus before performing the toe-tap exercise (p < 0.05). Individuals with flexible pes planus should be encouraged to perform myofascial release of the peroneus longus before the toe-tap exercise to improve the abductor hallucis activity and to elevate the medial longitudinal arch.

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

BackgroundThe 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? MethodsRelative 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. ResultOFM-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.

Accuracy and correlation between skin-marker based and radiographic measurements of medial longitudinal arch deformation

Static and dynamic measurements of the medial longitudinal arch (MLA) in the foot are critical across different clinical and biomechanical research fields. While MLA deformation can be estimated using skin-markers for gait analysis, the current understanding of the correlates between skin-marker based models and radiographic measures of the MLA is limited. This study aimed at assessing the correlation and accuracy of skin-marker based measures of MLA deformation with respect to standard clinical X-ray based measures, used as reference.20 asymptomatic subjects without morphological alterations of the foot volunteered in the study. A lateral X-ray of the right foot of each subject was taken in monopodalic upright posture with and without a metatarsophalangeal-joint dorsiflexing wedge. MLA angle was estimated in the two foot postures and during gait using 16 skin-marker based models, which were established according to the marker set of a validated multi-segment foot kinematic protocol. The error of each model in tracking MLA deformation was assessed and correlated with respect to standard radiographic measurements.Estimation of MLA deformation was highly affected by the skin-marker models. Skin-marker models using the marker on the navicular tuberosity as apex of the MLA angle showed the smallest errors (about 2 deg) and the largest correlations (R = 0.64–0.65; p < 0.05) with respect to the radiographic measurements.According to the outcome of this study, skin-marker based definitions of the MLA angle using the navicular tuberosity as apex of the arch may provide a more accurate estimation of MLA deformation with respect to that from radiographic measures.

Correlation of body mass index with dynamic balance using Y-Balance Test in adults with the Flexible Flat Foot: An Analytical Correlation Research Protocol

Background: Balance is one of the primary requirements for both static and dynamic activities. Body MassIndex (BMI) is measurement for estimating excess body fat. The Lower Quarter Y-Balance Test (YBTLQ) is a screening instrument that measures single-leg balance in different directions. Flexible flatfoot isthe postural aspect with depressed medial longitudinal arch, pronated subtalar joint and valgus position ofcalcaneus, evident only in weight-bearing position.Methods: An analytical correlation study with 255 participants (Purposive sampling) will be taken as perinclusion and exclusion criteria with study duration of 3 years. The BMI, sit to stand Navicular Drop Test(SSNDT), limb length and medial longitudinal arch angle (MLAA) will be measured and compared. Themean score of the Y Balance Test in different categories of BMI will be compared by performing one wayANOVA test. The mean score of the Y Balance Test between two groups in each category of BMI will becompared by Bonferroni t-test.Conclusion: The study aims the correlation of BMI with the dynamic balance on Y-balanced test in adultswith flexible flat foot. The expected outcome of study will concentrate on the significant correlation of YBalance Test in different categories of BMI.

The effect of changing foot progression angle using real-time visual feedback on rearfoot eversion during running.

Atypical rearfoot in/eversion may be an important risk factor for running-related injuries. Prominent interventions for atypical rearfoot eversion include foot orthoses, footwear, and taping but a modification derived from gait retraining to correct atypical rearfoot in/eversion is lacking. We aimed to investigate changes in rearfoot in/eversion, subtalar pronation, medial longitudinal arch angle, and selected lower limb joint biomechanics while performing toe-in/toe-out running using real-time visual feedback. Fifteen female runners participated in this study. Subjects performed toe-in/toe-out running using real-time visual feedback on foot progression angle, which was set ±5° from habitual foot progression angle. 3D kinematics of rearfoot in/eversion, subtalar supination/pronation, medial longitudinal arch angle, foot progression angle, hip flexion, ab/adduction and internal/external rotation, knee flexion, ankle dorsiflexion, and ankle power were analyzed. A repeated-measures ANOVA followed by pairwise comparisons was used to analyze changes between three conditions. Toe-in running compared to normal and toe-out running reduced peak rearfoot eversion (mean difference (MD) with normal = 2.1°; p<0.001, MD with toe-out = 3.5°; p<0.001), peak pronation (MD with normal = -2.0°; p<0.001, MD with toe-out = -3.4; p = <0.001), and peak medial longitudinal arch angle (MD with normal = -0.7°; p = 0.022, MD with toe-out = -0.9; p = 0.005). Toe-out running significantly increased these kinematic factors compared to normal and toe-in running. Toe-in running compared to normal running increased peak hip internal rotation (MD = 2.3; p<0.001), and reduced peak knee flexion (MD = 1.3; p = 0.014). Toe-out running compared to normal running reduced peak hip internal rotation (MD = 2.5; p<0.001), peak hip ab/adduction (MD = 2.5; p<0.001), peak knee flexion (MD = 1.5; p = 0.003), peak ankle dorsiflexion (MD = 1.6; p<0.001), and peak ankle power (MD = 1.3; p = 0.001). Runners were able to change their foot progression angle when receiving real-time visual feedback for foot progression angle. Toe-in/toe-out running altered rearfoot kinematics and medial longitudinal arch angle, therefore supporting the potential value of gait retraining focused on foot progression angle using real-time visual feedback when atypical rearfoot in/eversion needs to be modified. It should be considered that changes in foot progression angle when running is accompanied by changes in lower limb joint biomechanics.

Effects of Running Surface Stiffness on Three-Segment Foot Kinematics Responses with Different Shod Conditions.

Objective The aim of this study was to investigate the effects of surface stiffness on multisegment foot kinematics and temporal parameters during running. Methods Eighteen male subjects ran on three different surfaces (i.e., concrete, artificial grass, and rubber) in both heeled running shoes (HS) and minimal running shoes (MS). Both these shoes had dissimilar sole profiles. The heeled shoes had a higher sole at the heel, a thick base, and arch support, whereas the minimal shoes had a flat base sole. Indeed, the studied biomechanical parameters responded differently in the different footwear during running. Subjects ran in recreational mode speed while 3D foot kinematics (i.e., joint rotation and peak medial longitudinal arch (MLA) angle) were determined using a motion capture system (Qualysis, Gothenburg, Sweden). Information on stance time and plantar fascia strain (PFS) was also collected. Results Running on different surface stiffness was found to significantly affect the peak MLA angles and stance times for both HS and MS conditions. However, the results showed that the joint rotation angles were not sensitive to surface stiffness. Also, PFS showed no relationship with surface stiffness, as the results were varied as the surface stiffness was changed. Conclusion The surface stiffness significantly contributed towards the effects of peak MLA angle and stance time. These findings may enhance the understanding of biomechanical responses on various running surfaces stiffness in different shoe conditions.

SUBTALAR JOINT IN NEUTRAL AND RELAXED POSITIONS FOR EVALUATION OF MEDIAL LONGITUDINAL ARCH

ABSTRACTObjective: The medial longitudinal arch is the main structure of load bearing and shock absorption of the foot. The evaluation of medial longitudinal arch, such as the navicular height, the medial longitudinal arch angle and the Feiss line should be performed with the subtalar joint in the neutral and relaxed position. Our study analyzed the correlation between the measurements of the subtalar joint in neutral and relaxed positions during the evaluation tests of the medial longitudinal arch.Methods: This is a cross-sectional study, in which 51 healthy volunteers (102 feet; 36 women; 28 ± 5 years, 1.66 ± 0.10 m; 24.5 ± 4.5 kg/m2) had their navicular height, medial longitudinal arch angle and Feiss line measured in the neutral and relaxed positions. The correlation between the measures was evaluated using Pearson’s test.Results: A strong correlation of the 102 feet Feiss line measurements between neutral and relaxed positions (r = 0.81) was observed, and a moderate correlation between the medial longitudinal arch angle (r = 0.78) and between navicular height in neutral and relaxed positions (r = 0.76).Conclusion: The measurements of the longitudinal medial arch between the neutral and relaxed positions are strongly correlated. Therefore, it is not necessary to measure the medial longitudinal arch in both neutral and relaxed positions. Level of Evidence II, Diagnostic Studies - Investigating a diagnostic test.

Is Foot Type an Indicator of Anterior Cruciate Ligament Injury in Football Players?

Background: Prevention of sports injuries requires a comprehensive analysis of intrinsic and extrinsic factors of injuries in athletes. Pre-participation, evaluation, biomechanical assessment and new technology are helpful in providing useful information about the cause and mechanism of sports injury and strategies for injury prevention. However, there have been only few previous investigations which can conclusively correlate certain foot types with specific knee injury. Objective: To determine any relationship between foot type and ACL injury. Method: A case-control study design was adopted for this clinical study to investigate foot- type as a risk factor for ACL injury. 35 professional football players with a surgical history of ACL reconstruction and 35 professional football players without any history of ACL injury participated in our study. Foot types were determined by measuring their medial longitudinal arch angle and rearfoot-leg eversion angle. Questionnaire which included other variables of ACL injury were filled and analysed to eliminate their interference in this study. Odds ratio was used as reliable statistical tool to estimate the relative risk. Result: There was a significant relationship between pronated foot type as a risk factor for ACL injury. Conclusion: This suggests that pronated foot is a risk factor for ACL injury in football players.

The effect of changing mediolateral center of pressure on rearfoot eversion during treadmill running

IntroductionAtypical rearfoot eversion is an important kinematic risk factor in running-related injuries. Prominent interventions for atypical rearfoot eversion include foot orthoses, footwear, and taping, yet a running gait retraining is lacking. Therefore, the aim was to investigate the effects of changing mediolateral center of pressure (COP) on rearfoot eversion, subtalar pronation, medial longitudinal arch angle (MLAA), hip kinematics and vertical ground reaction force (vGRF). MethodsFifteen healthy female runners underwent gait retraining under three conditions. Participants were instructed to run normally, on the lateral (COP lateral) and medial (COP medial) side of the foot. Foot progression angle (FPA) was controlled using real-time visual feedback. 3D measurements of rearfoot eversion, subtalar pronation, MLAA, FPA, hip kinematics, vGRF and COP were analyzed. A repeated-measures ANOVA followed by pairwise comparisons was used to analyze changes in outcome between three conditions. Data were also analyzed using statistic parameter mapping. ResultsRunning on the lateral side of the foot compared to normal running and running on the medial side of the foot reduced peak rearfoot eversion (mean difference (MD) with normal 3.3°, p < 0.001, MD with COP medial 6°, p < 0.001), peak pronation (MD with normal 5°, p < 0.001, MD with COP medial 9.6°, p=<0.001), peak MLAA (MD with normal 2.3°, p < 0.001, MD with COP medial 4.1°, p < 0.001), peak hip internal rotation (MD with normal 1.8°, p < 0.001), and peak hip adduction (MD with normal running 1°, p = 0.011). Running on the medial side of the foot significantly increased peak rearfoot eversion, pronation and MLAA compared to normal running. SignificanceThis study demonstrated that COP translation along the mediolateral foot axis significantly influences rearfoot eversion, MLAA, and subtalar pronation during running. Running with either more lateral or medial COP reduced or increased peak rearfoot eversion, peak subtalar pronation, and peak MLAA, respectively, compared to normal running. These results might use as a basis to help clinicians and researchers prescribe running gait retraining by changing mediolateral COP for runners with atypical rearfoot eversion or MLAA.

Effect of Isometric Hip Abduction on Foot and Ankle Muscle Activity and Medial Longitudinal Arch During Short-Foot Exercise in Individuals With Pes Planus.

The improvement of hip joint stability can significantly impact knee and rearfoot mechanics. Individuals with pes planus have a weak abductor hallucis (AbdH), and the tibialis anterior (TA) may activate to compensate for this. As yet, no studies have applied isometric hip abduction (IHA) for hip stability during short-foot exercise (SFE). To compare the effects of IHA on the muscle activity of the AbdH, TA, peroneus longus (PL), and gluteus medius (Gmed), as well as the medial longitudinal arch (MLA) angle during sitting and standing SFE. Two-way repeated analyses of variance were used to determine the statistical significance of AbdH, TA, PL, and Gmed electromyography activity, as well as the change in MLA angle. University research laboratory. Thirty-two participants with pes planus. The participants performed SFE with and without isometric hip abduction in sitting and standing positions. Surface electromyography was used to measure the activity of the AbdH, TA, PL, and Gmed muscles, and Image J was used to measure the MLA angle. Significant interactions between exercise type and position were observed in terms of the PL muscle activity and in the change in MLA angle only, while other muscles showed significant main effects. The IHA during SFE significantly increased the AbdH muscle activity, while the TA muscle activity was significantly lower. The muscle activity of Gmed and PL was significantly increased in the standing position compared with sitting, but there was no significant difference with or without IHA. The change in the MLA angle was significantly greater in SFE with IHA in a standing position than in the other SFE conditions. IHA may be an effective method for reducing compensatory TA activity and increasing AbdH muscle activity during SFE for individuals with pes planus.

Effect of dynamic guidance-tubing short foot gait exercise on muscle activity and navicular movement in people with flexible flatfeet.

Navicular drop is a common plantar deformity which makes the plantar medial longitudinal arch (MLA) collapse and leads to other deformities in lower extremities. Active structures are from intrinsic and extrinsic foot muscle activities such as abductor hallucis (AbdH), tibialis anterior (TA), tibialis posterior, flexor hallucis brevis, flexor digitorum brevis during dynamic situations. As AbdH plays a role as a dynamic elevator of MLA, the importance of AbdH has been emphasized and the proper recruitment of both intrinsic and extrinsic muscle is crucial for stabilization of MLA during dynamic weight bearing condition. Because the short foot (SF) exercise is difficult to perform and tends to activate the intrinsic muscles concentrically rather than a natural coordination of concentric-isometric-eccentric activation, we have developed the guidance-tubing SF gait (GFG) exercise. We investigated the effect of GFG exercise on muscle activity, AbdH:TA activity ratio, MLA angle, and foot pressure distribution during walking compared to SF gait (SFG) exercise. Thirty-two subjects with flexible flat feet were divided into two groups and performed SFG exercise with (GFG) and without guidance-tubing (SFG) for seven serial days. AbdH muscle activity significantly increased from foot flat to heel rise in the GFG group (p = 0.006). The AbdH:TA activity ratio significantly increased in both the SFG (p = 0.015) group and GFG group (p = 0.006). MLA angles significantly decreased in both the SFG group (p = 0.001) and GFG group (p = 0.000), and the decrement was significantly higher in the GFG group (p = 0.001). The foot pressure distribution did not show any statistically significant change. The result of this study provides a clinical implication for training MLA supporter muscles in individuals with flat feet. The overactive muscle must be inhibited first, then facilitation and strengthening are followed respectively.