Effect of 3D printed foot orthoses stiffness and design on foot kinematics and plantar pressures in healthy people

BackgroundFoot orthoses (FOs) have been widely prescribed to alter various lower limb disorders. FOs’ geometrical design and material properties have been shown to influence their impact on foot biomechanics. New technologies such as 3D printing provide the potential to produce custom shapes and add functionalities to FOs by adding extra-components.Research questionThe purpose of this study was to determine the effect of 3D printed FOs stiffness and newly design postings on foot kinematics and plantar pressures in healthy people.MethodsTwo pairs of ¾ length prefabricated 3D printed FOs were administered to 15 healthy participants with normal foot posture. FOs were of different stiffness and were designed so that extra-components, innovative flat postings, could be inserted at the rearfoot. In-shoe multi-segment foot kinematics as well as plantar pressures were recorded while participants walked on a treadmill. One-way ANOVAs using statistical non-parametric mapping were performed to estimate the effect of FOs stiffness and then the addition of postings during the stance phase of walking.ResultsIncreasing FOs stiffness altered frontal and transverse plane foot kinematics, especially by further reducing rearfoot eversion and increasing the rearfoot abduction. Postings had notable effect on rearfoot frontal plane kinematics, by enhancing FOs effect. Looking at plantar pressures, wearing FOs was associated with a shift of the loads from the rearfoot to the midfoot region. Higher peak pressures under the rearfoot and midfoot (up to +31.7 %) were also observed when increasing the stiffness of the FOs.Significance3D printing techniques offer a wide range of possibilities in terms of material properties and design, providing clinicians the opportunity to administer FOs that could be modulated according to pathologies as well as during the treatment by adding extra-components. Further studies including people presenting musculoskeletal disorders are required.     

The immediate effects of sensorimotor foot orthoses on foot kinematics in healthy adults

BackgroundSensorimotor foot orthoses is an alternative concept, which in addition to mechanical effects, are designed to change muscle activation by altering sensory input to the plantar surface of the foot. However, there is little evidence of how these affect the kinematics of the foot during gait.Research questionThe aim of the study was to explore the immediate effect of calcaneal medial heel bars and retrocapital bars on foot kinematics during the stance phase of gait.MethodsKinematic data were collected from 32 healthy individuals using an eight camera motion capture system and a six-degrees-of-freedom multi-segment foot model in three different orthotic conditions; calcaneal medial heel bar, retrocapital bar, and no orthosis. Vector field statistical analysis was performed to explore the effect of the orthotic conditions over the kinematic time series curves during stance phase. Peak median and interquartile ranges were also reported during the different phases of stance.ResultsThe calcaneal medial bar significantly decreased rearfoot eversion for the majority of the stance phase and compensatory increased midfoot eversion during the entire stance phase compared to the no orthosis condition. The retrocapital bar rotated the foot externally significantly abducting the rearfoot for the entire stance phase and the midfoot for the majority of stance phase.SignificanceThe calcaneal medial heel bar and retrocapital bar significantly altered the foot kinematics in a way that may benefit patients with abnormal pronation and intoeing gait.     

The biomechanical effects of pronated foot function on gait. An experimental study

The relationship between foot kinematics and the development of lower extremity musculoskeletal disorders (MSD) has been the focus of recent attention. However, most studies evaluated static foot type and not dynamic foot function. The purpose was to compare lower limb and foot kinematics, and plantar pressures during gait in physically active individuals with pronated and non-pronated foot function. Foot function in 154 adult participants was documented as pronated (n = 63) or neutral (n = 91) using 2 established methods: The Foot Posture Index and the Center of Pressure Excursion Index. Difference between the groups in triplanar motion of the lower limb during barefoot gait was evaluated using a 3D motion capture system incorporating the Oxford Foot Model. Dynamic parameters of plantar pressure were recorded using a pressure platform. Anterior-posterior pelvic tilt range of motion (ROM), peak knee internal rotation, forefoot dorsiflexion ROM, peak forefoot abduction, and rearfoot eversion were all increased in those with pronated foot function. Hallux contact time and time to peak force under the medial forefoot were increased with pronated foot function, and maximal force under the lateral forefoot was reduced. Pronated foot function affected the whole lower limb kinematic chain during gait. These kinematic alterations could increase the risk of developing MSD. Further studies should elucidate the relationship between pronated foot function and MSD, and, if confirmed, foot function should be evaluated in clinical practice for patients with lower limb and low back pain.     

The effect of low-mobile foot posture on multi-segment medial foot model gait kinematics

A number of in vitro, invasive in vivo, and non-invasive marker based multi-segment foot models (MSFMs) have reported significant motion in the articulations distal to the calcaneus during gait. Few studies, however, have applied a MSFM to the investigation of the effect of foot posture on gait kinematics. Differences in stance phase kinematics between participants with low-mobile (LMF) (n = 11) versus “typical” (TYPF) (n = 11) foot postures were investigated using a multi-segment medial foot model. Three-dimensional position and stance phase excursions of four functional articulations (rearfoot complex [RC], calcaneonavicular complex [CNC], medial forefoot, first metatarsophalangeal complex) were quantified using an eight optical camera motion analysis system (Vicon Motus, Vicon Motions Systems, Centennial, CO) and a custom written software program (Matlab 7.0.1, The MathWorks, Natick, MA), respectively. Excursions during four subphases of stance phase (loading response, midstance, terminal stance, pre-swing) at each of the functional articulations were compared using multivariate analyses of variance (α ≤ 0.05). Results revealed significantly decreased LMF group CNC abduction excursion (p = 0.047) during midstance. During pre-swing, LMF group RC inversion excursion was significantly increased (p = 0.032) and eversion excursion was significantly decreased (p = 0.003) compared to the TYPF group. When these differences are considered in conjunction with the kinematic patterns of other foot/leg segments and functional articulations, the changes may suggest dysfunction of normal leg-calcaneus coupling and the constrained tarsal mechanism associated with low-mobile foot postures.     

Reliability of peak foot pressure in patients with previous diabetic foot ulceration

BackgroundPrevious reliability studies on peak plantar pressure measurements in patients with previous diabetic foot ulceration (DFU) did not stratify their analyses according to whether the foot had a previous ulcer.Research questionDoes test-retest reliability of peak foot pressure measurements from the various foot regions differ between the ulcerated and non-ulcerated feet?MethodsData from 23 participants with peripheral neuropathy and healed plantar DFU were analysed in this test-retest reliability comparison study. Plantar pressure was evaluated on two sessions using Pedar^®-X in-shoe system, with a mean of 7.2 days (SD = 1.6) between sessions.ResultsThe intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated for 10 foot regions. Overall, test-retest reliability was excellent (ICCs, 0.82 to 0.95) for all peak pressure variables. CV ranged between 6.3% and 18.3%, and exceeded 15% over the hallux and medial forefoot regions in the ulcer foot (18.3% and 16.4%, respectively). Hallux peak pressure CV was significantly higher over the ulcer foot than over the non-ulcer foot (5.7%, 95% CI, 1.7%–10.2%). Peak pressure CV over the forefoot also tended to be higher over the ulcer foot (medial forefoot: 6.1%, 95% CI, -0.5%–14.5%; lateral forefoot: 4.1%, 95%CI, -0.7%–11.1%).SignificancePeak plantar foot pressure may be useful to distinguish between groups of patients with peripheral neuropathy and healed plantar DFU. However, clinical decisions based on ulcer foot hallux and forefoot peak pressure measurements should be interpreted with caution.     

Forefoot angle determines duration and amplitude of pronation during walking

The biomechanical mechanisms that link foot structure to injuries of the musculoskeletal system during gait are not well understood. This study had two parts. The purpose of part one was to determine the relation between clinical rearfoot and forefoot angles and foot angles as they make contact with the ground. The purpose of part two was to determine the effects of large vs. moderate values of both forefoot and rearfoot inversion angles at foot contact on foot kinematics. Clinical foot angle, the relationship between the foot and an axis extrinsically defined relative to the ground, was calculated from digital photographs taken in a prone position. During three speeds of over-ground walking, we measured frontal plane rearfoot and forefoot angle relative to the ground at foot contact, and the following stance phase kinematic measures: amplitude of rearfoot and forefoot eversion, duration of rearfoot and forefoot eversion, and duration between heel-off and onset of rearfoot and forefoot inversion. We found that the clinical forefoot angle predicted the forefoot angle at foot contact. Individuals with a large inversion forefoot angle at contact also had greater amplitude of forefoot eversion and everted longer during stance. We discuss the possible mechanisms for the increased risk of injury to the hip reported for individuals that have a large clinical forefoot angle in non-weight bearing. Equally important is the finding that rearfoot angle at contact did not predict the motions of the rearfoot or forefoot during stance.     

Dynamic plantar pressure patterns in children and adolescents with Charcot-Marie-Tooth disease

BackgroundThe dynamic plantar pressure patterns of children and adolescents with Charcot-Marie-Tooth (CMT) disease and its relationship to musculoskeletal alterations may help to understand the natural history of the disease and improve therapeutic interventions.Research questionThe study compared dynamic plantar pressure patterns in children and adolescents with and without CMT. It also tested the associations between isometric muscle strength (IMS), passive range of motion (ROM), foot posture and dynamic plantar pressure patterns in CMT.MethodsThis cross-sectional study compared children and adolescents (aged 8–18 years) with CMT (n = 40) with a typical group (n = 40). The plantar pressure distribution during gait was recorded, and the contact area (CA), peak pressure (PP), contact time (CT) and pressure-time integral (PTI) in five foot regions (rearfoot, midfoot lateral, midfoot medial, lateral forefoot and medial forefoot) were analysed. The IMS of the dorsiflexors and plantar flexors, passive ROM, and foot posture were also recorded.ResultsPP (medial midfoot and medial forefoot) and PTI (rearfoot, lateral midfoot and medial forefoot) were higher in children with CMT compared with the typical group. The adolescents with CMT presented a less CA (whole foot) and a higher CT (medial midfoot) when compared with typical group. For CMT, in the medial midfoot, plantar flexor IMS associated with PP (β=-11.54, p = 0.01) and PTI (β=-3.38, p = 0.04); supinated foot posture associated with PP (β = 33.89, p = 0.03) and PTI (β = 12.01, p = 0.03).SignificanceChildren with CMT showed clear changes in most of the dynamic plantar pressure variables, while adolescents with CMT showed changes mostly in CA and CT. This information together with the associations established between supinated foot, dorsiflexion ROM and plantar flexions IMS can be useful for guiding rehabilitation professionals in their therapies.     

In-shoe plantar pressure measurements for the evaluation and adaptation of foot orthoses in patients with rheumatoid arthritis: A proof of concept study

ObjectivesImproving foot orthoses (FOs) in patients with rheumatoid arthritis (RA) by using in-shoe plantar pressure measurements seems promising. The objectives of this study were to evaluate (1) the outcome on plantar pressure distribution of FOs that were adapted using in-shoe plantar pressure measurements according to a protocol and (2) the protocol feasibility.MethodsForty-five RA patients with foot problems were included in this observational proof-of concept study. FOs were custom-made by a podiatrist according to usual care. Regions of Interest (ROIs) for plantar pressure reduction were selected. According to a protocol, usual care FOs were evaluated using in-shoe plantar pressure measurements and, if necessary, adapted. Plantar pressure–time integrals at the ROIs were compared between the following conditions: (1) no-FO versus usual care FO and (2) usual care FO versus adapted FO. Semi-structured interviews were held with patients and podiatrists to evaluate the feasibility of the protocol.ResultsAdapted FOs were developed in 70% of the patients. In these patients, usual care FOs showed a mean 9% reduction in pressure–time integral at forefoot ROIs compared to no-FOs (p = 0.01). FO adaptation led to an additional mean 3% reduction in pressure–time integral (p = 0.05). The protocol was considered feasible by patients. Podiatrists considered the protocol more useful to achieve individual rather than general treatment goals. A final protocol was proposed.ConclusionsUsing in-shoe plantar pressure measurements for adapting foot orthoses for patients with RA leads to a small additional plantar pressure reduction in the forefoot. Further research on the clinical relevance of this outcome is required.     

Comparison of foot muscle morphology and foot kinematics between recreational runners with normal feet and with asymptomatic over-pronated feet

Over-pronated feet are common in adults and are associated with lower limb injuries. Studying the foot muscle morphology and foot kinematic patterns is important for understanding the mechanism of over-pronation related injuries. The aim of this study is to compare the foot muscle morphology and foot inter-segmental kinematics between recreational runners with normal feet and those with asymptomatic over-pronated feet. A total of 26 recreational runners (17 had normal feet and 9 had over-pronated feet) participated in this study and their foot type was assessed using the 6-item Foot Posture Index. Selected foot muscles were scanned using an ultrasound device and the scanned images were processed to measure the thickness and cross-sectional area of the muscles. Muscles of interest include abductor hallucis, abductor digiti minimi, flexor digitorum brevis and longus, tibialis anterior and peroneus muscles. Foot kinematic data during walking was collected using a 3D motion capture system incorporating the Oxford Foot Model. The results show that individuals with over-pronated feet have larger size of abductor hallucis, flexor digitorum brevis and longus and smaller abductor digiti minimi than controls. Higher rearfoot peak eversion and forefoot peak supination during walking were observed in individuals with over-pronated feet. However, during gait the forefoot peak abduction was comparable. These findings indicate that in active asymptomatic individuals with over-pronated feet, the foot muscle morphology is adapted to increase control of the foot motion. The morphological characteristics of the foot muscles in asymptomatic individuals with over-pronated feet may affect their foot kinematics and benefit prevention from injuries.     

Plantar pressure asymmetry and risk of stress injuries in the foot of young soccer players

BackgroundAsymmetries in the magnitude of plantar pressure are considered a risk factor for stress fracture of the fifth metatarsal in soccer athletes.ObjectiveTo investigate the presence of plantar pressure asymmetries among young soccer athletes.DesignObservational.SettingLaboratory.ParticipantsThirty young adolescents divided into a soccer player group (n = 15) or a matched control group (n = 15).Main outcome measuresMean plantar pressure was determined for seven different regions of the foot. Data were compared between the preferred and non-preferred foot, and between the groups, during barefoot standing on a pressure mat system.ResultsHigher pressure was found in the hallux, 5th metatarsal and medial rearfoot of the non-preferred foot in the young soccer players. These asymmetries were not observed in the control group. Magnitudes of plantar pressure did not differ between the groups.ConclusionYoung soccer players present asymmetries in plantar pressure in the hallux, 5th metatarsal and medial rearfoot, with higher pressure observed in the non-preferred foot.     

Biomechanical effects of three types of foot orthoses in individuals with posterior tibial tendon dysfunction

BackgroundPosterior tibial tendon dysfunction (PTTD) is characterized by degeneration of this tendon leading to a flattening of the medial longitudinal arch of the foot. Foot orthoses (FOs) can be used as a treatment option, but their biomechanical effects on individuals with PTTD are not yet fully understood.Research questionThe aim of this study was to investigate the effects of three types of FOs on gait biomechanics in individuals with PTTD.MethodsFourteen individuals were recruited with painful stage 1 or 2 PTTD based on Johnson and Strom’s classification. Quantitative gait analysis of the affected limb was performed in four conditions: shoes only (Shoe), prefabricated FO (PFO), neutral custom FO (CFO) and custom varus FO (CVFO) with a 5° medial wedge and a 4 mm medial heel skive. A curve analysis, using 1D statistical parametric mapping, was undertaken to assess differences in lower limb joint motion, joint moments and muscle activity over the stance phase of gait across conditions.ResultsDecreased hindfoot eversion angles, decreased ankle inversion moments and increased ankle eversion moments were observed with custom FOs compared to the Shoe and PFO conditions (p < 0.001). CFOs and CVFOs induced an increased knee abduction moment compared to Shoe (p < 0.001). No changes in hip kinematics and kinetics or in EMG activity of tested muscles were observed between conditions.SignificanceCustom orthoses may be more suitable than PFOs to decrease the pathological biomechanical outcomes observed in PTTD. Decreased ankle inversion moments during the stance phase could explain why custom orthoses are effective at reducing pain in PTTD patients. However, clinicians should be careful when prescribing custom orthoses for PTTD since unwanted collateral biomechanical effects can be observed at the knee.     

Effect of customised preformed foot orthoses on gait parameters in children with juvenile idiopathic arthritis: A multicentre randomised clinical trial

BackgroundChildren with juvenile idiopathic arthritis (JIA) can experience significant physical impairment of the lower extremity. Prolonged joint disease and symptoms may cause gait alterations such as reduced walking speed and increased plantar pressures in diseased areas of their feet. There is limited robust clinical trials investigating the effect of non-invasive mechanical therapies such as foot orthoses (FOs) on improving gait parameters in children with JIA.Research questionAre customised preformed FOs effective in improving gait parameters in children with JIA?MethodsA multicentre, parallel design, single-blinded randomised clinical trial was used to assess the gait impacts of customised preformed FOs on children with JIA. Children with a diagnosis of JIA, exhibiting lower limb symptoms and aged 5–18 were eligible. The trial group received a low-density full length, Slimflex Simple device which was customised chair side and the control group received a sham device. Peak pressure and pressure time integrals were used as the main gait outcomes and were measured using portable Tekscan gait analysis technology at baseline, 3 and 6 months. Differences at each follow-up were assessed using the Wilcoxon rank sum test.Results66 participants were recruited. Customised preformed FOs were effective in altering plantar pressures in children with JIA versus a control device. Reductions of peak pressures and pressure time integrals in the heel, forefoot and 5th metatarsophalangeal joint were statistically significant in favour of the trial group. This was associated with statistically significant increased midfoot contact with the trial device at baseline, 3 and 6-month data collections. The trial intervention was safe and well accepted by participants, which is reflected in the high retention rate (92%).SignificanceClinicians may prescribe customised preformed FOs in children with JIA to deflect pressure from painful joints and redistribute from high pressure areas such as the rearfoot and forefoot.     

Differences in lower-extremity kinematics between the male military personnel with and without plantar fasciitis

ObjectiveTo evaluate the factors that influence gait by comparing lower extremity kinematics during the stance phase of the gait cycle between individuals with and without plantar fasciitis.DesignA cross-sectional study.SettingMotion analysis research laboratory.ParticipantsThirty subjects with plantar fasciitis and 30 aged-matched controls.Main outcome measure(s)Range of motion of the lower extremity and multi-segment foot during gait using a three-dimensional motion analysis system.ResultsThe plantar fasciitis group showed significant differences in motion in the multi-segment foot, ankle, knee, and hip from the control group during various subphases of the stance phase. Specifically, relative to the control group, the plantar fasciitis group had more rearfoot adduction, forefoot eversion, ankle abduction, and hip abduction. They also had less midfoot dorsiflexion, forefoot dorsiflexion, knee extension, knee external rotation, and hip extension (all Ps < 0.05).ConclusionsIndividuals with plantar fasciitis exhibited more flexibility in the ankle-foot complex and poorer quality of lower-extremity movement than the group that did not have plantar fasciitis. Thus, differences in structures in both the ankle-foot complex as well as those in the hip and knee joints appear to be associated with the presence of plantar fasciitis.     

Segmental kinematic analysis of planovalgus feet during walking in children with cerebral palsy

Pes planovalgus (flatfoot) is a common deformity among children with cerebral palsy. The Milwaukee Foot Model (MFM), a multi-segmental kinematic foot model, which uses radiography to align the underlying bony anatomy with reflective surface markers, was used to evaluate 20 pediatric participants (30 feet) with planovalgus secondary to cerebral palsy prior to surgery. Three-dimensional kinematics of the tibia, hindfoot, forefoot, and hallux segments are reported and compared to an age-matched control set of typically-developing children. Most results were consistent with known characteristics of the deformity and showed decreased plantar flexion of the forefoot relative to hindfoot, increased forefoot abduction, and decreased ranges of motion during push-off in the planovalgus group. Interestingly, while forefoot characteristics were uniformly distributed in a common direction in the transverse plane, there was marked variability of forefoot and hindfoot coronal plane and hindfoot transverse plane positioning. The key finding of these data was the radiographic indexing of the MFM was able to show flat feet in cerebral palsy do not always demonstrate more hindfoot eversion than the typically-developing hindfoot. The coronal plane kinematics of the hindfoot show cases planovalgus feet with the hindfoot in inversion, eversion, and neutral. Along with other metrics, the MFM can be a valuable tool for monitoring kinematic deformity, facilitating clinical decision making, and providing a quantitative analysis of surgical effects on the planovalgus foot.     

An exploration of the effects of prefabricated and customized insoles on lower limb kinetics and kinematics during walking,stepping up and down tasks: A time series analysis

BackgroundPrefabricated and customized insoles are used in clinical practice to reduce foot pronation. Although data exist on the effects at key points within the stance phase, exploring the impact of different insoles using time series analysis may reveal more detail about their efficacy.Research questionWhat are the effects revealed by a time series analysis of arch-supported prefabricated insoles (PREFABRICATED) versus arch-supported prefabricated insoles customized with a 6º medial wedge (CUSTOMIZED) on the lower limb biomechanics during walking, stepping up and down tasks in individuals with pronated feet?MethodsNineteen individuals with excessive foot pronation performed walking, stepping up and down tasks using three insoles: CONTROL (flat insole), CUSTOMIZED, and PREFABRICATED. Angles and moments of ankle and knee coronal and hip transverse planes were compared between conditions using statistical parametric mapping (SPM).ResultsFor walking, CUSTOMIZED reduced ankle eversion moment compared to CONTROL during midstance and PREFABRICATED during propulsion. CUSTOMIZED decreased KAM during midstance and propulsion compared to PREFABRICATED. Compared to CONTROL, CUSTOMIZED and PREFABRICATED reduced hip internal rotation during propulsion and loading response, respectively. CUSTOMIZED decreased eversion movement during midstance and propulsion for the stepping up task. PREFABRICATED reduced eversion movement during midstance in comparison to CONTROL. For the stepping down task, CUSTOMIZED increased eversion movement during propulsion compared to PREFABRICATED. CUSTOMIZED reduced hip internal rotation angle for stepping up task during propulsion, decreased medial rotation movement during midstance compared to CONTROL, and reduced medial rotation during midstance compared to PREFABRICATED. CUSTOMIZED increased KAM for stepping up and down tasks during propulsion.SignificanceThese findings suggest that both CUSTOMIZED and PREFABRICATED reduce foot pronation. However, non-local effects, such as changes in KAM and hip internal rotation, were seen only in the CUSTOMIZED. Therefore, CUSTOMIZED may be preferable if the objective is to modify the knee and hip mechanics.     

Influence of a novel elastic foot orthosis in foot motion during locomotion in adults with mild flatfoot

BackgroundCollapse of the foot arch is a one of the risk factors in medial tibial stress syndrome. Custom-made foot orthoses are used to reduce the collapse of foot arch, but the orthoses are designed for a specific shoe and cannot be used in other shoes. We developed an elastic foot orthosis that is highly fitted on the foot using thin films, is lightweight, and can be used with any shoe or without shoes. The purpose of this study was to investigate foot kinematics with our elastic foot orthosis during walking and running.MethodsWe recruited 30 participants with asymptomatic flatfoot for this study. Foot kinematic data were recorded for treadmill walking, treadmill running, and over-ground walking. Foot kinematics were recorded in three conditions, barefoot (BF), with the elastic foot orthosis (EFO), and with sham foot orthosis (SFO), and foot strain was measured using a stretch strain sensor. The difference in foot strain from initial contact to maximum strain during gait was calculated as loading arch strain, which was reflected as forefoot eversion excursion. A one-way analysis of variance with Bonferroni test was performed to compare the loading arch strain among the three conditions.ResultsIn all tasks, loading arch strain with the EFO was significantly less than that in the BF and SFO conditions. Loading arch strain with the SFO was significantly more than that of BF in the treadmill gait condition.ConclusionOur results indicate that the EFO decreased foot strain during locomotion compared to without the EFO and is capable of supporting the foot arch during locomotion.     

Effects of medially wedged insoles on the biomechanics of the lower limbs of runners with excessive foot pronation and foot varus alignment

BackgroundExcessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles.Research questionThis study investigated the effects of a medially wedged insole at the forefoot and at the rearfoot on the lower limbs angles and internal moments of runners with excessive foot pronation and foot varus alignment.MethodsKinematic and kinetic data of 19 runners (11 females and 8 males) were collected while they ran wearing flat (control condition) and medially wedged insoles (insole condition). Both insoles had arch support. We used principal component analysis for data reduction and dependent t-test to compare differences between conditions.ResultsThe insole condition reduced ankle eversion (p = 0.003; effect size = 0.63); reduced knee range of motion in the transverse plane (p = 0.012; effect size = 0.55); increased knee range of motion in the frontal plane in early stance and had earlier knee adduction peak (p = 0.018; effect size = 0.52); reduced hip range of motion in the transverse plane (p = 0.031; effect size = 0.48); reduced hip adduction (p = 0.024; effect size = 0.50); reduced ankle inversion moment (p = 0.012; effect size = 0.55); and increased the difference between the knee internal rotation moment in early stance and midstance (p = 0.012; effect size = 0.55).SignificanceInsoles with 7˚ medial wedges at the forefoot and rearfoot are able to modify motion and moments patterns that are related to lower limb injuries in runners with increased foot pronation and foot varus alignment with some non-desired effects on the knee motion in the frontal plane.     

The effect of foot type on in-shoe plantar pressure during walking and running

The purpose of this study was to determine if low arch feet have altered plantar loading patterns when compared to normal feet during both walking and running. Fifty healthy subjects (34 normal feet, 16 flat feet) walked and ran five trials each at standard speeds. In-shoe pressure data were collected at 50 Hz. Contact area, peak pressure, maximum force, and force-time integral were analyzed in eight different regions of the foot. Foot type was determined by examining navicular height, arch angle, rearfoot angle, and a clinical score. A series of 2 x 2 repeated measures ANOVAs were used to determine statistical differences (alpha<0.05). A significant interaction existed between foot type and movement type for the maximum force in the medial midfoot. Total foot contact area, maximum force and peak pressure were significantly increased during running. Contact area in each insole area, except for the rearfoot, was significantly increased during running. Peak pressure and maximum force were significantly increased during running in each of the foot regions. However, the force-time integral was significantly decreased during running in the rearfoot, lateral midfoot, middle forefoot, and lateral forefoot. Significant differences between foot types existed for contact area in the medial midfoot and maximum force and peak pressure in the lateral forefoot. The maximum force and peak pressures were significantly decreased for the flat foot type. Therefore, individuals with a flat foot could be at a lower risk for lateral column metatarsal stress fractures, indicating that foot type should be assessed when determining an individual's risk for metatarsal stress fractures.