Medial Arch Research Articles

Pressure thresholds of the human foot: measurement reliability and effects of stimulus characteristics

Information related to reliable values of discomfort thresholds can help to improve the designs of various products. This study aimed to investigate the measurement reliabilities associated with pressure thresholds, while determining the effects of stimulus characteristics (stimulus area, indentation speed) of the human foot. An indentation apparatus was used with four sizes of indentation probes and three indentation speeds. In total, 13 locations on the right foot of 10 male and 10 female participants were tested to determine the pressure discomfort thresholds (PDT) and pressure pain thresholds (PPT). Results show that the tests had very good measurement reliability with intra-class correlations (ICC) greater than 0.8 for the PPT measurements and acceptable reliability (most ICC > 0.75, with a few between 0.5 and 0.75) for the PDT measurements, demonstrating that participants are capable of judging their pain and discomfort thresholds. Pressure sensitivity differs across locations of the foot, with the medial plantar arch of the foot being the most sensitive, followed by the dorsal surface of the foot. The heel area was the least sensitive. PPT and PDT are dependent on the stimulus characteristics of the area and the speed of indentation. A smaller area has a higher PPT and PDT, indicating significant effects of spatial summation. The increase of PDT and PPT at higher speeds may be partially explained by the increase in stiffness because foot tissue exhibits viscoelastic properties. The findings can have a significant impact on the design of footwear and other accessories for improved foot health and comfort. Statement of Relevance: This study investigated the threshold measurement reliability while determining the pressure sensitivity on the surface of the foot with varying stimulus characteristics. The findings may be very useful in the design of footwear and other accessories for improved comfort and reduced injuries.

Foot and ankle joint kinematics in rheumatoid arthritis cannot only be explained by alteration in walking speed

Rheumatoid arthritis (RA) manifests itself in the foot and ankle of RA patients. The foot and ankle joint kinematics of these patients differ from that of healthy subjects. However, the factors that lead to these differences are not yet fully understood. The aim of this study was to analyse the effect of walking speed and the disease process on foot and ankle joint kinematics of RA subjects. Gait recordings of 23 RA and 14 age-matched healthy subjects were performed and their foot and ankle joint kinematics were analysed during the stance phase of the gait cycle. Stance phase characteristics of the group of RA subjects and of the group of healthy subjects were compared. The healthy subjects walked at 100% (Vc), 75% (V75) and 50% (V50) of their comfortable walking speed. In a multi-level linear model significant differences between the two groups due to the factors walking speed and the disease process were analysed. The ankle dorsi-flexion, medial arch and hallux abduction motion at single-stance and toe-off were only influenced by the walking speed. The hallux maximum flexion at toe-off and the midfoot supination at single-stance were influenced by both the walking speed and the disease process. The hindfoot eversion motion at single-stance was only influenced by the disease process. In conclusion, the reduction of walking speed of RA subjects compared to healthy subjects does not explain all of the observed foot and ankle kinematics differences.

Plantar Pressure with and without Custom Insoles in Patients with Common Foot Complaints

Although many patients with foot complaints receive customized insoles, the choice for an insole design can vary largely among foot experts. To investigate the variety of insole designs used in daily practice, the insole design and its effect on plantar pressure distribution were investigated in a large group of patients. Mean, peak, and pressure-time-integral per sensor for 204 subjects with common foot complaints for walking with and without insoles was measured with the footscan® insole system (RSscan International). Each insole was scanned twice (precision3D), after which the insole height along the longitudinal and transversal cross section was calculated. Subjects were assigned to subgroups based on complaint and medial arch height. Data were analyzed for the total group and for the separate subgroups (forefoot or heel pain group and flat, normal or high medial arch group). The mean pressure significantly decreased under the metatarsal heads II-V and the calcaneus and significantly increased under the metatarsal bones and the lateral foot (p<0.0045) due to the insoles. However, similar redistribution patterns were found for the different foot complaints and arch heights. There was a slight difference in insole design between the subgroups; the heel cup was significantly higher and the midfoot support lower for the heel pain group compared to the forefoot pain group. The midfoot support was lowest in the flat arch group compared to the high and normal arch group (p<0.05). Although the insole shape was specific for the kind of foot complaint and arch height, the differences in shape were very small and the plantar pressure redistribution was similar for all groups. This study indicates that it might be sufficient to create basic insoles for particular patient groups.

Reliability of capturing foot parameters using digital scanning and the neutral suspension casting technique

BackgroundA clinical study was conducted to determine the intra and inter-rater reliability of digital scanning and the neutral suspension casting technique to measure six foot parameters. The neutral suspension casting technique is a commonly utilised method for obtaining a negative impression of the foot prior to orthotic fabrication. Digital scanning offers an alternative to the traditional plaster of Paris techniques.MethodsTwenty one healthy participants volunteered to take part in the study. Six casts and six digital scans were obtained from each participant by two raters of differing clinical experience. The foot parameters chosen for investigation were cast length (mm), forefoot width (mm), rearfoot width (mm), medial arch height (mm), lateral arch height (mm) and forefoot to rearfoot alignment (degrees). Intraclass correlation coefficients (ICC) with 95% confidence intervals (CI) were calculated to determine the intra and inter-rater reliability. Measurement error was assessed through the calculation of the standard error of the measurement (SEM) and smallest real difference (SRD).ResultsICC values for all foot parameters using digital scanning ranged between 0.81-0.99 for both intra and inter-rater reliability. For neutral suspension casting technique inter-rater reliability values ranged from 0.57-0.99 and intra-rater reliability values ranging from 0.36-0.99 for rater 1 and 0.49-0.99 for rater 2.ConclusionsThe findings of this study indicate that digital scanning is a reliable technique, irrespective of clinical experience, with reduced measurement variability in all foot parameters investigated when compared to neutral suspension casting.

Estudo da impressão plantar obtida durante o teste de Jack em crianças

OBJETIVO: Avaliar as impressões plantares durante o teste de Jack em crianças quantificando e observando os resultados numa faixa etária crítica para a formação do arco plantar. MÉTODO: Avaliamos 60 crianças brancas (120 pés) sendo 35 meninos e 25 meninas com idades entre 2 e 5 anos, sem queixas ortopédicas. Simulamos o teste de Jack com uma órtese em cunha de 45º apoiada sob o hálux. Obtivemos impressões em apoio monopodálico bilateralmente utilizando um pedígrafo. O exame dividiu-se em duas etapas: com e sem o uso da órtese. A metodologia de Valenti e Volpon foi utilizada para mensurar as impressões plantares e os dados obtidos foram analisados estatisticamente. RESULTADOS: Os valores dos índices de Valenti e Volpon diminuiram quando a órtese foi utilizada. A diferença entre os índices com ou sem órtese diminuiu gradualmente com a progressão etária. CONCLUSÕES: É possível quantificar o teste de Jack pelwas impressões plantares pelo método de Valenti e Volpon. A variação do seu formato apresentou tendência a ser menor a partir dos 4 anos. O teste de Jack perdeu gradativamente a capacidade de modificar a impressão plantar com a idade, diminuindo sua acuidade como parâmetro de bom prognóstico na formação do arco longitudinal medial. Nível de Evidência: Nível IV, estudo descritivo observacional.

The Effect of Arch Pad on Ankle Kinematics during Running

The purpose of this study was to evaluate the change in three-dimensional (3D) ankle joint kinematics on the arch pad. Ten male subjects performed running trials on treadmill, and ten motion capture system were used to record a position data of the reflected markers on the lower limb. Two conditions (no support and support: arch pad) were compared with the joint angles which were analyzed by the Cardan method. As a result, ankle joint eversion angles with support shoe (−6.5±2.5) were significantly lower than that with no support shoe (−10.2±3.2) (p 0.25, p>0.11). Shoes with medial arch support or using special shoe inserts may help correct one's running form by reducing pronation and may reduce risk of running injury.

Low-Dye Taping Versus Medial Arch Support in Managing Pain and Pain-Related Disability in Patients With Plantar Fasciitis

Plantar fasciitis is thought to develop because of repeated mechanical stresses. This study aimed to compare 2 means of foot arches support-low-Dye tape (LDT) and medial arch support (MAS)-in patients with plantar fasciitis. Thirty patients with unilateral plantar fasciitis (23 men and 7 women) were randomly assigned to the LDT or MAS groups. Both groups were assessed before and after experiment for pain and foot function. Both groups received 9 sessions over 3 weeks consisting of ultrasound and calf muscles stretching. They were instructed to maintain supportive intervention (LDT or MAS) throughout this period. Pre-post comparison showed reduced pain and improved function in both groups. Between-groups analysis showed non-significant difference in pre-VAS and pre-FPDS. Post-VAS and post-FPDS showed significant improvement in patients in MAS group. Results indicate that MAS is more convenient for short-term management of pain and disability in patients with plantar fasciitis than LDT.

Spring Ligament Reconstruction for Advanced Flatfoot Deformity with the Use of an Achilles Allograft

Patients with flexible flatfoot can present with a variety of deformities, including heel valgus, medial arch collapse, and midfoot abduction. The spring (calcaneonavicular) ligament plays a major role in stabilizing the medial longitudinal arch. Its compromise, when severe enough and accompanied by failure of other ligaments, is manifested by talonavicular collapse on lateral radiographs along with uncoverage of the talar head by the navicular on anteroposterior radiographs. In this article, we describe a method of reconstructing the spring ligament complex by using an Achilles allograft. This reconstruction is indicated in cases of severe talonavicular collapse manifested by forefoot abduction that persists despite appropriate lateral column lengthening. The decision to perform such reconstruction is supported by preoperative magnetic resonance imaging demonstrating severe compromise of the spring ligament and confirmed intraoperatively once it is determined that lateral column lengthening provides insufficient correction of the deformity.

Stage IV Adult-Acquired Flatfoot Deformity Deltoid Ligament Reconstruction

Patients with flexible stage IV flatfoot present with valgus ankle deformity in addition to medial arch collapse, resulting in hind foot valgus and midfoot abduction. The ankle deformity is best addressed at the time of flatfoot reconstruction. In this article, we describe a method of reconstructing the deltoid ligament complex by using an Achilles allograft tendon. The graft is prepared with a bone block that is placed in a talar tunnel and secured to a screw post in the lateral talar body. The graft is passed through an oblique tibial tunnel, drilled from medial to lateral starting at the medial malleolus and exiting out the lateral tibia above the level of the ankle. The reconstruction is indicated in cases in which ankle valgus can be passively reduced and there is no bone on bone contact in the ankle joint. A previous report showed promising results in a small cohort of patients using a peroneus longus autograft.

The effects of walking speed on forefoot, hindfoot and ankle joint motion

Background Foot and ankle joint kinematic differences have been identified between healthy subjects and subjects with various pathologies suffering from foot and ankle impairments. Changes in temporal factors such as walking speed and double stance time are also found in these pathological conditions. As such, in theory, these factors would also influence the kinematics and hence make it difficult to ascertain the effects of the disease on the kinematics. The aim of this study was to analyse foot and ankle kinematics from gait recordings of healthy subjects walking at comfortable and slower speeds. Methods Gait patterns of 14 healthy subjects were recorded. The subjects were first asked to walk at a comfortable speed and then at predefined speeds of 75% and 50% of their comfortable walking speed respectively. Temporal variables were calculated. Foot and ankle joint kinematics were determined from marker-recordings. Findings The subjects walked at mean velocities of 1.28 m/s, 0.97 m/s and 0.65 m/s. With decreasing walking speed the minimum tibio-talar plantar-flexion and maximum hallux dorsi-flexion at toe-off decreased significantly between 3° and 9°. The minimum medial arch at toe-off and minimum midfoot supination at mid-stance were significantly affected by the walking speed. The corresponding individual session differences were small (1°–2°), but the reliability was high and hence the differences were considered clinically relevant. Interpretation Walking speed significantly affected foot and ankle kinematics. Studies aiming to improve the understanding of the effects of foot and ankle pathologies on foot and ankle kinematics should take the walking speed into account.

Reconstruction of the Spring Ligament Using a Peroneus Longus Autograft Tendon Transfer

The spring (calcaneonavicular) ligament provides one of the main static supports of the medial arch of the foot. The purpose of this study was to retrospectively assess the results of patients having undergone reconstruction of the spring ligament using a peroneus longus tendon autograft left at its distal attachment and passed through the navicular followed by either a calcaneal or tibial drill hole, a technique not previously reported. Thirteen consecutive patients (14 feet) (mean age, 63.5 +/- 12.3 years) undergoing flatfoot surgery with spring ligament reconstruction for cases in which lateral column lengthening failed to correct talonvavicular deformity were reviewed. The AOFAS, FAOS, and SF-36 were assessed along with standard weightbearing radiographs at a followup visit at a mean of 8.9 +/- 1.8 years after surgery. Hindfoot alignment and eversion strength were measured. The AOFAS ankle-hindfoot score increased from 43.1 to 90.3 (\hbox{p}\leq 0.001). The postoperative FAOS pain subscale and overall SF-36 were 83.7 (range, 67.9 to 100), and 77.3 (range 37.8 to 95.6) respectively. The AP first tarsometatarsal angle (p = 0.015), talonavicular coverage angle (p = 0.003), lateral calcaneal pitch (p = 0.002), and lateral talonavicular angle (p = 0.017) improved significantly and were within normal ranges postoperatively. The mean hindfoot alignment measured 2.7 degrees of valgus. All but one patient had normal (5/5) eversion strength. Reconstruction of the spring ligament resulted in few complications and might be considered as an alternative to arthrodesis in patients with ruptures of the spring ligament and deformity that does not correct fully with bony procedures alone.

Mirror foot – a reflection on three cases

Mirror-foot abnormalities are distinctly uncommon entities and represent extreme forms of congenital duplication. We present a reflection on three different cases of mirror foot and discuss their surgical management. The first patient had a right-sided mirror foot with a central great toe and three complete medial rays. The second patient had quadruplication of the left great toe ray. The third had a full complement of metatarsals associated with two extra complete rays placed medial to the great toe of the right foot. All patients underwent complex ray resection and concurrent reconstruction of the medial arch of foot. All three cases of mirror foot presented and were operated on in the pre-ambulatory period. All three patients recovered with good functional and aesthetic results. Follow-up duration ranged from 3 to 5 years. Surgical treatment of the mirror foot is less complicated than that of its upper limb equivalent. Essentially, there must be an initial surgical reduction in the number of digits, coupled with tendon transfers as necessary to maintain foot arches.

Kinematic differences between normal and low arched feet in children using the Heidelberg foot measurement method

The purpose of this study was to investigate the kinematics of normal arched and low arched feet in children and use this data to quantify the differences between the two foot types during walking gait. Multi-segment foot motion was measured, using the Heidelberg foot measurement method (HFMM), for 25 normal arched feet and 27 low arched feet in 9–12-year-old children. The kinematic differences in the foot between the two groups during walking were relatively small, except for the medial arch and forefoot supination angles. The magnitude of the medial arch angle was approximately 10° greater in the low arched group than the normal arched group throughout the gait cycle. There was a significant difference found in the forefoot supination angle ( p < 0.03), relative to the midfoot, between the two groups at initial heel strike, and maximum and minimum values throughout the gait cycle. The values for the normal group were significantly higher in all these angles indicating that the forefoot of the low arched foot remains less pronated during the gait cycle. There was no significant difference in the motion of the rearfoot between the two foot types. The results of this study provide normative values for children's feet and highlight the mechanical differences in flexible flat feet in this age group. This data contributes to knowledge on foot kinematics in children and will be valuable for future research on the structure, function and potential treatment of the flexible flat foot.

Computational Model of the Lower Leg and Foot/Ankle Complex: Application to Arch Stability

The aim of this work was the design and evaluation of a computational model to predict the functional behavior of the lower leg and foot/ankle complex whereby joint behavior was dictated by three-dimensional articular contact, ligamentous constraints, muscle loading, and external perturbation. Three-dimensional bony anatomy was generated from stacked CT images after which ligament mimicking elements were attached and muscle/body loading added to recreate the experimental conditions of selected cadaveric studies. Comparisons of model predictions to results from two different experimental studies were performed for the function of the medial arch in weight bearing stance and the contributions of soft tissue structures to arch stability. Sensitivity simulations evaluated selected in situ strain and stiffness values for ligament tissue. The greatest contributor to arch stability was the plantar fascia, which provided 79.5% of the resistance to arch collapse, followed by the plantar ligaments (12.5%), and finally the spring ligament (8.0%). Strains measured after plantar fasciotomy increased in the remaining plantar ligament by approximately 300% and spring ligament by approximately 200%. Sensitivity tests varying both in situ strain and stiffness across reported standard deviations showed that functional trends remained the same and true to experimental data, although absolute magnitudes changed. While not measured experimentally, the model also predicted that load can increase dramatically in the remaining plantar tissues when one of such tissues is removed. Overall, computational predictions of stability and soft tissue load sharing compared well with experimental findings. The strength of this simulation approach lies in its capacity to predict biomechanical behavior of modeled structures and to capture physical parameters of interest not measurable in experimental simulations or in vivo.

Analysis of ankle alignment abnormalities as a risk factor for pediatric flexible flat foot

Majority of paediatric flat feet are flexible and asymptomatic;less than 0.1% of all flat feet are rigid. If these can be diagnosed and managed early, then various complications can be prevented and they will remain asymptomatic. This study was conducted to analyse the ankle rotational malalignments in the natural course of flexible flat foot in children. Seventy-six patients of flexible flat foot and one hundred controls were included in this study. The height of foot arches was judged clinically by inspecting the height of the medial arch and by measuring the arch index on weight-bearing podograms. Tibial torsion and bimalleolar angle were assessed in all subjects. Tibial torsion was assessed in the first twenty subjects (ten cases and ten controls) both by clinical methods (foot-thigh angle) and CT. As no statistical difference in the two methods was observed, tibial torsion was measured by clinical methods only in the remaining subjects. Bimalleolar angle was measured on weight-bearing podograms in all subjects. For a minimum of two years, cases were followed up regularly with a standard conservative protocol and the height of the arches observed. Majority of cases of flexible flat foot were found to have increased tibial torsion and increased foot-bimalleolar angle (high talar spin). The severity of collapse of the medial arch and the response to conservative treatment was found to correlate with these rotational mal-alignments of the ankle. Ankle rotational mal-alignments were seen to make these flexible flat foot deformities more complex and less responsive to conservative treatment.KEY WORDS: Flat foot; Pediatric flat feet; Flexible flat feet

Identification of Static and Dynamic Properties Induced by Hip Changes to Flexion Withdrawal Reflex in Chronic Human Spinal Cord Injury

The aim of this study was to investigate the static and dynamic properties of the flexion withdrawal reflex modulated by hip changes in human spinal cord injury. The influence of the hip position and passive movement were tested in six subjects with chronic spinal cord injury. Each subject was placed in a supine position and lower limb was fixed with the knee at 23.7±16.0 degrees flexion and the ankle at 33.3±5.2 degrees plantar flexion. A train of 10 stimulus pulses were applied at 200Hz to the skin of the medial arch to elicit the nociceptive flexion reflexes. From results of the regression analysis, activation of flexor muscles (tibialis anterior and illiopsoas) during static hip angle changes has a linear relationship with respect to hip angle (P<0.05). As the hip flexion angle increases, the EMG activity decreases. A significant linear relationship was also found between the reflex activity of flexor muscle (illiopsoas) and hip angular velocity during both hip flexion and hip extension movement (P<0.05). In order to validate the reflex response, we compared the static and dynamic gains of estimated activation with measured electromyogram of tibialis anterior. From this study, we postulate that flexor muscle activities of nociceptive flexion reflex have linear relationship with hip angle and angular velocity.

Effect of Medial Arch Support on Displacement of the Myotendinous Junction of the Gastrocnemius During Standing Wall Stretching

Controlled laboratory study. To examine the effects of standing wall stretching with and without medial arch support (WMAS versus WOMAS) on the displacement of the myotendinous junction (DMTJ) of the medial gastrocnemius, rearfoot angle, and navicular height in subjects with neutral foot alignment and pes planus. Standing wall stretching is often prescribed to increase ankle dorsiflexion range of motion for sports fitness and rehabilitation. However, the effect of standing wall stretching WMAS on DMTJ is unknown. Fifteen subjects with neutral foot alignment and 15 subjects with pes planus performed standing wall stretching under WMAS and WOMAS conditions. Measurements of DMTJ and rearfoot position were performed using ultrasonography and video imaging. Navicular height was measured using a ruler. Dependent variables were examined with a 2-way mixed-design analysis of variance. The 2 factors were foot type (neutral foot versus pes planus) and stretching condition (WMAS versus WOMAS). There were significant interactions of medial arch support by foot type for DMTJ, rearfoot angle, and navicular drop (P<.001). A post hoc paired t test showed that standing wall stretching in the WMAS condition significantly increased the DMTJ, compared to stretching in the WOMAS condition, in subjects with neutral foot (mean +/- SD, 9.6 +/- 1.6 versus 10.5 +/- 1.6 mm; difference, 0.9 mm; 99% CI: 0.4-1.4 mm) and in those with pes planus (10.0 +/- 1.8 versus 12.7 +/- 2.0 mm; difference, 2.7 mm; 99% CI: 1.9-3.5 mm) (P<.001). When comparing WOMAS and WMAS, the difference in DMTJ (1.8 mm; 99% CI: 0.9-2.7 mm) was significantly greater in subjects with pes planus than in those with neutral foot (P<.001). Standing wall stretching with medial arch support maintained subtalar joint neutral position and increased the length of the gastrocnemius in subjects with pes planus. When prescribing standing wall stretching, clinicians need to emphasize the use of medial arch support to effectively stretch the gastrocnemius in subjects with pes planus.

Hindfoot Alignment Valgus Moment Arm Increases in Adult Flatfoot with Achilles Tendon Contracture

Adult acquired flatfoot is often associated with Achilles tendon contracture and may be associated with isolated spring ligament insufficiency without Achilles tendon contracture. We have studied the hypothesis that standing valgus hindfoot alignment moment arm is increased in adult acquired flatfoot with Achilles tendon contracture when compared to adult acquired flatfoot without Achilles tendon contracture. The standing hindfoot alignment, standing lateral tibial-calcaneal angle, lateral talo-first metatarsal angle, lateral medial cuneiform arch height, and anteroposterior talonavicular coverage angle were measured in 22 patients with a clinical diagnosis of adult acquired flatfoot with one foot with clinical Achilles tendon contracture and one without that diagnosis. We compared the adult acquired flatfoot group to a control group of 15 patients with no foot or ankle deformities or previous foot or ankle surgeries. In patients with flatfoot and Achilles tendon contracture, there was a significantly increased valgus hindfoot alignment, talo-first metatarsal angle, talonavicular coverage angle, tibiocalcaneal angle and a decreased arch height when compared to the control group. In all flatfeet, we found an increased tibiocalcaneal angle. In both flatfoot groups, an increasing tibiocalcaneal angle and an increasing talo-first metatarsal angle was correlated to a decreasing arch height. In adult acquired flatfoot without Achilles tendon contracture diagnosed by clinical exam, an increasing talonavicular coverage angle was correlated to an increasing talo-first metatarsal angle and a decreasing arch height. Adults with flatfoot and Achilles tendon contracture have a significantly increased standing hindfoot valgus alignment moment arm and other associated deformities.

Flexor reflex decreases during sympathetic stimulation in chronic human spinal cord injury

A better understanding of autonomic influence on motor reflex pathways in spinal cord injury is important to the clinical management of autonomic dysreflexia and spasticity in spinal cord injured patients. The purpose of this study was to examine the modulation of flexor reflex windup during episodes of induced sympathetic activity in chronic human spinal cord injury (SCI). We simultaneously measured peripheral vascular conductance and the windup of the flexor reflex in response to conditioning stimuli of electrocutaneous stimulation to the opposite leg and bladder percussion. Flexor reflexes were quantified using torque measurements of the response to a noxious electrical stimulus applied to the skin of the medial arch of the foot. Both bladder percussion and skin conditioning stimuli produced a reduction (43–67%) in the ankle and hip flexor torques ( p < 0.05) of the flexor reflex. This reduction was accompanied by a simultaneous reduction in vascular conductance, measured using venous plethysmography, with a time course that matched the flexor reflex depression. While there was an overall attenuation of the flexor reflex, windup of the flexor reflex to repeated stimuli was maintained during periods of increased sympathetic activity. This paradoxical depression of flexor reflexes and minimal effect on windup is consistent with inhibition of afferent feedback within the superficial dorsal horn. The results of this study bring attention to the possible interaction of motor and sympathetic reflexes in SCI above and below the T5 spinal level, and have implications for clinicians in spasticity management and for researchers investigating motor reflexes post SCI.

The effects of unilateral medial arch support stimulation on plantar pressure and center of pressure adjustment in young gymnasts

The purpose of this study was to examine the contribution of tactile afferents from the medial arch of the foot on postural control. The center of pressure (CoP) position and right/left plantar pressure distributions of 13 gymnasts, with and without a medial arch support, were recorded by a force platform coupled with a baropedometry analysis. Stimulation of the subject's plantar sole was accomplished using a 3 mm thick medial arch insert. Right arch stimulation induced an ipsilateral increase of plantar pressure and a contralateral displacement of the CoP to the left. Left arch support also resulted in an ipsilateral increase in plantar pressure and displacement of the CoP to the right. Stimulation of the plantar arch may induce a perception that the body's center of mass has shifted toward the stimulated foot. To maintain stability, individuals may then shift their CoP in the opposite direction. This response may involve compensatory muscle activation strategies to adjust posture. Clinicians may apply these results in their use of foot orthoses to address postural anomalies in patients.