Effect of inverted orthoses on lower-extremity mechanics in runners

Effect of Different Foot Orthosis Inverted Angles on Walking Kinematics in Females with Flexible Flatfeet

Background

Although the inverted technique was shown to be more effective compared to other orthotic designs for the treatment of flatfeet, the biomechanical mechanisms underlying the therapeutic effect of the inverted angle orthoses is still unclear. Therefore, the aim of this study was to examine the effect of different inverted angles of foot orthoses on walking kinematics in females with flexible flatfeet.

Methods

Thirty-one female adults with flexible flatfeet aged 18-35 years old participated in this study. Kinematic data of the hip, knee, and ankle were collected via BTS motion-capture system during walking under three test conditions in random order: with shoes only; with 15° inverted orthoses; and with 25° inverted orthoses.

Results

Compared to the shoes only condition, both the 15° and 25° inverted orthotic conditions significantly decreased the maximum ankle plantarflexion angle during loading response, maximum ankle dorsiflexion angle during mid-stance, maximum ankle external rotation angle, and maximum ankle internal rotation angle. The maximum ankle plantarflexion angle at toe-off showed a significant decrease with the 25° inverted angle orthosis compared to both the 15° inverted angle and shoes only conditions. No significant differences were found in the knee kinematic variables, maximum hip extension angle, and maximum hip adduction angle between test conditions.

Conclusion

Using inverted orthoses at 15° and 25° inverted angles resulted in significant changes in ankle joint kinematics during walking in female adults with flexible flatfeet. A 25° inverted angle orthosis significantly decreased ankle plantarflexion during push-off, potentially impacting gait mechanics. This suggests that a smaller inverted angle may be more effective for managing flexible flatfeet in female adults.

Assessment of a New Lateral Cushioned Casting Orthosis: Effects on Peroneus Longus Muscle Electromyographic Activity During Running

Background:

Classical medial wedge (CMW) orthoses have been prescribed to treat overpronation foot pathologies in runners. The effects of a novel supination orthosis (NSO) on the surface electromyography (EMG) activity of the peroneus longus (PL) muscle during a complete cycle of running have yet to be tested.

Purpose/Hypothesis:

The purpose of this study was to compare the EMG activity of the PL in participants wearing CMW orthoses and NSOs versus neutral running shoes (NRS) during a full cycle of running gait. It was hypothesized that the PL muscle activity would be lower for the NSO compared with CMW or NRS.

Study Design:

Controlled laboratory study.

Methods:

Included were 31 healthy recreational runners of both sexes (14 male and 17 female; mean age, 38.58 ± 4.02 years) with a neutral Foot Posture Index and standard rearfoot-strike pattern. Participants ran on a treadmill at 9 km/h while wearing NSO (3-, 6-, and 9-mm thicknesses), CMW (3-, 6-, and 9-mm thicknesses), and NRS, for a total of 7 different conditions randomly selected, while the EMG signal activity of the PL was recorded for 30 seconds. Each trial was recorded 3 times, and the intraclass correlation coefficient (ICC) to test reliability of the measurements was calculated. The Wilcoxon pair to pair nonparametric test with Bonferroni correction was performed to analyze differences among the conditions.

Results:

The reliability of all assessments was almost perfect (ICC, >0.81). For both the CMW and NSO, regardless of thickness, the PL activity was statistically significantly lower compared with the NRS (P < .05 for all). For all CMW thicknesses, the PL activity was lower compared with the respective NSO thicknesses, with the 3-mm thickness having the largest difference (CMW_3mm, 18.63 ± 4.64 vs NSO_3mm, 20.78 ± 4.99 mV; P < .001).

Conclusion:

Both CMW and NSO produced reduced EMG activity of the PL muscle; therefore, they can be prescribed to treat overpronation pathologies without associated PL strain concerns. In addition, the NSO saved the enhancement material placed on the medial-rear side of CMW, making it easier to wear sports shoes.

Clinical Relevance:

Knowing the safety of CMW and NSO will aid in understanding treatments for overpronation pathologies.

Anti-pronator components are essential to effectively alter lower-limb kinematics and kinetics in individuals with flexible flatfeet

BACKGROUND

Foot orthoses are commonly used to correct for foot alterations and especially address excessive foot pronation in individuals with flatfeet. In recent years, 3D printing has taken a key place in orthotic manufacturing processes as it offers more options and can be patient specific. Hence, the purpose of this study was to evaluate whether stiffness of 3D printed foot orthoses and a newly designed rearfoot posting have an effect on lower limb kinematics and kinetics in individuals with flatfeet.

METHODS

Nineteen patients with flexible flatfeet were provided two pairs of customized 3D printed ¾ length orthotics. Foot orthoses were of different stiffness and could feature a rearfoot posting, consisting of 2-mm carbon fiber plate. Lower limb kinematics and kinetics were computed using a multi-segment foot model. One-way ANOVAs using statistical non-parametric mapping, refined by effect sizes, were performed to determine the magnitude of the effect between conditions.

FINDINGS

Foot orthoses stiffness had little effect on midfoot and forefoot biomechanics. Reductions in midfoot eversion and forefoot abduction were observed during short periods of stance with rigid foot orthoses. Adding the posting had notable effects on rearfoot kinematics and on the ankle and knee kinetics in the frontal plane; it significantly reduced the eversion angle and inversion moment at the ankle, and increased the knee abduction moment.

INTERPRETATION

Using an anti-pronator component is more effective than increasing foot orthoses stiffness to observe a beneficial impact of foot orthoses on the control of excessive foot pronation in individuals with flatfeet.

Can lower extremity anatomical measures and core stability predict dynamic knee valgus in young men?

INTRODUCTION

Dynamic knee valgus (DKV) is a risk factor for lower extremity injuries such as anterior cruciate ligament and patellofemoral pain syndrome. Purpose of the current study was to investigate the relationship between lower extremity anatomical measures (LEAM) and core stability with DKV during the single-leg squat.

METHODS

Thirty healthy men aged between 18 and 28 years participated in this cross-sectional biomechanical study.DKV was assessed using a 6-camera motion analysis system during a single-leg squat task. Anteversion of hip, hip internal and external rotation, Q-angle, knee hyperextension, tibial torsion, tibia vara, plantar arch index, and core stability were measured using standard clinical procedures. To predict DKV, a multiple linear regression model was used.

RESULT

The stability index negatively and plantar arch index positively predicted greater DKV during the single-leg squat task (P = 0.001 and P = 0.09, respectively). Research variables together predicted 82% of the variance in DKV (F(4,26) = 28.09, p < 0.001). However, relationships between other variables and DKV were not found.

CONCLUSION

The core stability index and plantar arch index were associated with observed DKV during the single-leg squat. These results suggested that proximal and distal variables to the knee should be considered when evaluating individuals who present DKV during the single-leg squat.

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

BACKGROUND

Excessive foot pronation during running in individuals with foot varus alignment may be reduced by medially wedged insoles.

RESEARCH QUESTION

This 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.

METHODS

Kinematic 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.

RESULTS

The 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).

SIGNIFICANCE

Insoles 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.

Biomechanical Effect of Foot Orthoses on Rearfoot Motions and Joint Moment Parameters in Patients with Flexible Flatfoot

Background

The effect of foot orthoses in terms of kinematics and kinetics during walking could be affected on different geometrical designs. Therefore, the purpose of this study was to compare the biomechanical and clinical effects of 3 different insoles on rearfoot motion (RFM) and ankle joint moment parameters.

Material/Methods

Twenty eight university students with flexible flatfoot were recruited for this study, and each participant was asked to wear 3 different insoles: normal insole without arch support function, type A insole with only arch support function, and type B insole with both arch support and cushion pads for shock absorbing functions. Three-dimensional motion analysis was performed to compute the ranges and peak orientation angles of RFM and ankle joint moment parameters.

Results

The type A and type B insoles exhibited significantly smaller peak everted position and evertor moment than the normal insole. Also, the type A insole showed significantly smaller range of rearfoot motion in the longitudinal axis and the length of MA (moment arm) in the mediolateral axis than the normal insole.

Conclusions

The use of the type A insole using arch support function was induced to promote a cautious gait pattern associated with a relatively lower potential risk compared to the normal insole. The type A and type B insoles could be important to positively reduce the possibility of injury. Also, the smaller length of MA in the type A insole might have a contribution to the decrease of ankle joint evertor moment.

Effect of foot orthosis design on lower limb joint kinematics and kinetics during walking in flexible pes planovalgus: A systematic review and meta-analysis

BACKGROUND

Foot orthoses are commonly used for the management of excessive foot pronation in people with pes planovalgus. However, results are inconsistent due to variability in orthosis geometrical designs. This systematic review with meta-analysis aimed to classify and investigate the effects of foot orthoses, based on their design, in terms of lower limb kinematics and kinetics in people with pes planovalgus.

METHODS

Electronic databases were searched up until August 2017. Peer-reviewed journal studies including adult participants with flexible pes planovalgus and reporting kinematics and kinetics effects of foot orthoses during walking were included and classified based on the orthosis design. Eleven studies were retained and assessed according to methodological (mean 76.1%; range [63.2%-84.2%] - high) and biomechanical (mean 71.6%; range [44.4%-100%] - moderate) qualities. Meta-analysis was performed by calculating the effect size, using standardized mean differences, between control and orthotics conditions.

FINDINGS

Meta-analysis revealed less rearfoot eversion with the use of foot orthoses including medial forefoot or both forefoot and rearfoot posting. However, no significant effect of foot orthoses with arch support and neutral rearfoot posting to control excessive foot pronation were found. In terms of kinetics, none of the foot orthoses showed effects.

INTERPRETATION

Using medial posting is the most effective foot orthotic feature to reduce the peak rearfoot eversion and to control excessive foot pronation. Nevertheless, heterogeneity between study protocols contributes to the low evidences of foot orthoses effects on kinematics and kinetics during walking in people with pes planovalgus.

Effects of different medial arch support heights on rearfoot kinematics

Background

Foot orthoses are usually assumed to be effective by optimizing mechanically dynamic rearfoot configuration. However, the effect from a foot orthosis on kinematics that has been demonstrated scientifically has only been marginal. The aim of this study was to examine the effect of different heights in medial arch-supported foot orthoses on rear foot motion during gait.

Methods

Nineteen asymptomatic runners (36±11years, 180±5cm, 79±10kg; 41±22km/week) participated in the study. Trials were recorded at 3.1 mph (5 km/h) on a treadmill. Athletes walked barefoot and with 4 different not customized medial arch-supported foot orthoses of various arch heights (N:0 mm, M:30 mm, H:35 mm, E:40mm). Six infrared cameras and the `Oxford Foot Model´ were used to capture motion. The average stride in each condition was calculated from 50 gait cycles per condition. Eversion excursion and internal tibia rotation were analyzed. Descriptive statistics included calculating the mean ± SD and 95% CIs. Group differences by condition were analyzed by one factor (foot orthoses) repeated measures ANOVA (α = 0.05).

Results

Eversion excursion revealed the lowest values for N and highest for H (B:4.6°±2.2°; 95% CI [3.1;6.2]/N:4.0°±1.7°; [2.9;5.2]/M:5.2°±2.6°; [3.6;6.8]/H:6.2°±3.3°; [4.0;8.5]/E:5.1°±3.5°; [2.8;7.5]) (p>0.05). Range of internal tibia rotation was lowest with orthosis H and highest with E (B:13.3°±3.2°; 95% CI [11.0;15.6]/N:14.5°±7.2°; [9.2;19.6]/M:13.8°±5.0°; [10.8;16.8]/H:12.3°±4.3°; [9.0;15.6]/E:14.9°±5.0°; [11.5;18.3]) (p>0.05). Differences between conditions were small and the intrasubject variation high.

Conclusion

Our results indicate that different arch support heights have no systematic effect on eversion excursion or the range of internal tibia rotation and therefore might not exert a crucial influence on rear foot alignment during gait.

The Influence of a Prefabricated Foot Orthosis on Lower Extremity Mechanics During Running in Individuals With Varying Dynamic Foot Motion

Study Design Controlled laboratory study, cross-sectional. Background Orthotic prescription is often based on the premise that the mechanical effects will be more prominent in individuals with greater calcaneal eversion. Objective To compare the effects of a prefabricated foot orthosis on lower extremity kinematics and kinetics between recreational athletes with high and low calcaneal eversion during running. Methods Thirty-one recreational athletes were included in this study. Three-dimensional kinematic and kinetic data were collected while running with and without a foot orthosis. Participants were grouped based on the degree of calcaneal eversion during the running trials relative to a standing trial (dynamic foot motion). The effects of the orthosis on the frontal and transverse plane angles and moments of the hip and knee were compared between the 10 participants with the greatest and least amount of dynamic foot motion. Results There were no significant interactions (group by orthotic condition) for any of the kinematic or kinetic variables of interest. Conclusion The effects of an orthosis on the mechanics of the hip and knee do not appear to be dependent on an individual's dynamic foot motion. J Orthop Sports Phys Ther 2016;46(9):749-755. Epub 5 Aug 2016. doi:10.2519/jospt.2016.6253.

Runners with patellofemoral pain have altered biomechanics which targeted interventions can modify: A systematic review and meta-analysis

Patellofemoral pain (PFP) is the most prevalent running pathology and associated with multi-level biomechanical factors. This systematic review aims to guide treatment and prevention of PFP by synthesising prospective, observational and intervention studies that measure clinical and biomechanical outcomes in symptomatic running populations. Medline, Web of Science and CINAHL were searched from inception to April 2015 for prospective, case-control or intervention studies in running-related PFP cohorts. Study methodological quality was scored by two independent raters using the modified Downs and Black or PEDro scales, with meta-analysis performed where appropriate. 28 studies were included. Very limited evidence indicates that increased peak hip adduction is a risk factor for PFP in female runners, supported by moderate evidence of a relationship between PFP and increased peak hip adduction, internal rotation and contralateral pelvic drop, as well as reduced peak hip flexion. Limited evidence was also identified that altered peak force and time to peak at foot level is a risk factor for PFP development. Limited evidence from intervention studies indicates that both running retraining and proximal strengthening exercise lead to favourable outcomes in both pain and function, but only running retraining significantly reduces peak hip adduction, suggesting a possible kinematic mechanism. Put together, these findings highlight limited but coherent evidence of altered biomechanics which interventions can alter with resultant symptom change in females with PFP. There is a clear need for high quality prospective studies of intervention efficacy with measurement of explanatory mechanisms.

The effect of orthotics on intersegmental foot kinematics and the EMG activity of select lower leg muscles

BACKGROUND

Persons with exertional related leg pain are managed using orthoses. This study aimed to determine the effectiveness of two orthoses in altering foot motion and muscle activity in symptomatic individuals.

METHODS

52 subjects with lower extremity pain complaints of a non-traumatic, mechanical origin received one of two orthoses. Foot kinematics and EMG activity were recorded while treadmill walking in 3 footwear conditions. The peak EMG activity of the sandal and sandal orthotic trials (normalized to peak barefoot values) and foot motion during 4 subphases of stance were obtained. Using a multivariate multilevel model via linear mixed models, the effect of orthoses within these phases on motion and EMG was determined.

RESULTS

An effect of orthotic type was not present for any of the rearfoot or forefoot motions (p>.10). A significant effect of footwear and orthotic type on first ray motion (p<.05) during subphases 2 and 4 was seen. During subphase 4 an interaction effect between footwear condition and orthotic type on tibialis posterior EMG activity (p=.036) was present.

CONCLUSION

Orthoses are unable to control rear or midfoot motion but appear to control first ray motion and during late stance, affect tibialis posterior muscle activity. Public trials registry number: NCRT02143947.

The Effects of Orthotic Intervention on Multisegment Foot Kinematics and Plantar Fascia Strain in Recreational Runners

Chronic injuries are a common complaint in recreational runners. Foot orthoses have been shown to be effective for the treatment of running injuries but their mechanical effects are still not well understood. This study aims to examine the influence of orthotic intervention on multisegment foot kinematics and plantar fascia strain during running. Fifteen male participants ran at 4.0 m·s−1 with and without orthotics. Multisegment foot kinematics and plantar fascia strain were obtained during the stance phase and contrasted using paired t tests. Relative coronal plane range of motion of the midfoot relative to the rearfoot was significantly reduced with orthotics (1.0°) compared to without (2.2°). Similarly, relative transverse plane range of motion was significantly lower with orthotics (1.1°) compared to without (1.8°). Plantar fascia strain did not differ significantly between orthotic (7.1) and nonorthotic (7.1) conditions. This study shows that although orthotics did not serve to reduce plantar fascia strain, they are able to mediate reductions in coronal and transverse plane rotations of the midfoot.

Consensus-based recommendations of Australian podiatrists for the prescription of foot orthoses for symptomatic flexible pes planus in adults

BACKGROUND

Foot orthoses are commonly used for symptomatic flexible pes planus in adults. However, there are no clinical guidelines for the prescription of customised foot orthoses that are specific to this population. The aim of this study was to investigate prescription habits of Australian podiatrists for customised foot orthoses for symptomatic flexible pes planus in adults and to develop consensus-based practice recommendations for the prescription of these foot orthoses.

METHODS

A four round Delphi survey was undertaken with 24 podiatric experts to establish current use and rationale for individual prescription variables of customised foot orthoses for symptomatic flexible pes planus in adults. Round one determined prescription use (consensus) and rounds two, three and four determined the rationale for use (agreement) of prescription variables across the rearfoot, midfoot, forefoot, as well as accommodation and materials used. For consensus and agreement to be accepted, 70% of the respondents were required to use or agree on the rationale for use of individual prescription variables.

RESULTS

Consensus was reached in round one for two variables, choice of shell material (polyolefin) and when to prescribe a forefoot post balanced to perpendicular. In rounds two, three and four, agreement was reached for 52 statements related to the rationale for use of individual prescription variables, including when to prescribe: an inverted cast pour [heel in an inverted position], an inverted rearfoot post, a medial heel (Kirby) skive, minimal/maximum arch fill, a medial flange, a forefoot post and common orthotic accommodations.

CONCLUSION

This study found consensus or agreement for the use of several prescription variables for customised foot orthoses for symptomatic flexible pes planus in adults. The findings were used to develop the Foot orthosis Prescription Recommendations for symptOmatic flexible Pes planus in adults (FootPROP) proforma, to guide clinicians and researchers in the prescription of customised foot orthoses for this population.

Between-day reliability of a cluster-based method for multisegment kinematic analysis of the foot-ankle complex

BACKGROUND

Detailed description of foot pronation-supination requires multisegment evaluation of the kinematics of the foot-ankle complex. There are noninvasive methods with independent (single) tracking markers attached directly to the skin. However, these methods are inconsistent with the usual rigid segments assumption. In contrast, using clustered markers is compatible with this assumption and is necessary for analyses that need tracking markers to be distant from the foot (eg, shod walking). This study investigated the between-day reliability of a cluster-based method for multisegment analysis of foot-ankle angles related to pronation-supination.

METHODS

Ten healthy adults participated in the study. An anatomically based, three-dimensional model comprising the shank, calcaneus, and forefoot was created. Rigid clusters of tracking markers were used to determine the relative positions and motions of the segments. Mean positions were measured with the subtalar joint in neutral position during standing. Furthermore, mean angles, peaks, and timings of peaks were measured during the stance phase of walking. All of the variables were measured twice, with a 1-week interval. To evaluate reliability, intraclass correlation coefficients were calculated for discrete variables and coefficients of multiple correlation for entire gait curves.

RESULTS

Intraclass correlation coefficients varied from 0.8 to 0.93 for the angles obtained when the subtalar joint was in neutral and from 0.76 to 0.9 for walking variables. Coefficients of multiple correlation varied from 0.93 to 0.97 for walking curves.

CONCLUSIONS

The method described has good to high reliability and provides a systematic method for multisegment kinematic evaluation of foot-ankle pronation-supination.

Forefoot angle at initial contact determines the amplitude of forefoot and rearfoot eversion during running

BACKGROUND

Clinically, foot structures are assessed intrinsically - relation of forefoot to rearfoot and rearfoot to leg. We have argued that, from a biomechanical perspective, the interaction of the foot with the ground may influence forces and torques that are propagated through the lower extremity. We proposed that a more appropriate measure is an extrinsic one that may predict the angle the foot makes with ground at contact. The purposes of this study were to determine if the proposed measure predicts contact angles of the forefoot and rearfoot and assess if the magnitude of those angles influences amplitude and duration of foot eversion during running.

METHODS

With the individual in prone, extrinsic clinical forefoot and rearfoot angles were measured relative to the caudal edge of the examination table. Participants ran over ground while frontal plane forefoot and rearfoot contact angles, forefoot and rearfoot eversion amplitude and duration were measured. Participants were grouped twice, once based on forefoot contact inversion angle (moderate<median and large>median) and once based on rearfoot contact inversion angle (moderate<median and large>median).

FINDINGS

The forefoot and rearfoot extrinsic clinical angles predicted, respectively, the forefoot and rearfoot angles at ground contact. Large forefoot contact angles were associated with greater amplitudes (but not durations) of forefoot and rearfoot eversion during stance. Rearfoot contact angles, however, were associated with neither amplitudes nor durations of forefoot and rearfoot eversion.

INTERPRETATION

Possible mechanisms for the increased risk of running injuries associated with large forefoot angles are discussed.

Ankle dorsiflexion among healthy men with different qualities of lower extremity movement

CONTEXT

Lower extremity movement patterns have been implicated as a risk factor for various knee disorders. Ankle-dorsiflexion (DF) range of motion (ROM) has previously been associated with a faulty movement pattern among healthy female participants.

OBJECTIVE

To determine the association between ankle DF ROM and the quality of lower extremity movement during the lateral step-down test among healthy male participants.

DESIGN

Cross-sectional study.

SETTING

Training facility of the Israel Defense Forces.

PATIENTS OR OTHER PARTICIPANTS

Fifty-five healthy male Israeli military recruits (age = 19.7 ± 1.1 years, height = 175.4 ± 6.4 cm, mass = 72.0 ± 7.6 kg).

INTERVENTION(S)

Dorsiflexion ROM was measured in weight-bearing and non-weight-bearing conditions using a fluid-filled inclinometer and a universal goniometer, respectively. Lower extremity movement pattern was assessed visually using the lateral step-down test and classified categorically as good or moderate. All measurements were performed bilaterally.

MAIN OUTCOME MEASURE(S)

Weight-bearing and non-weight-bearing DF ROM were more limited among participants with moderate quality of movement than in those with good quality of movement on the dominant side (P = .01 and P = .02 for weight-bearing and non-weight-bearing DF, respectively). Non-weight-bearing DF demonstrated a trend toward a decreased range among participants with moderate compared with participants with good quality of movement on the nondominant side (P = .03 [adjusted P = .025]). Weight-bearing DF was not different between participants with good and moderate movement patterns on the nondominant side (P = .10). Weight-bearing and non-weight-bearing ankle DF ROM correlated significantly with the quality of movement on both sides (P < .01 and P < .05 on the dominant and nondominant side, respectively).

CONCLUSIONS

Ankle DF ROM was associated with quality of movement among healthy male participants. The association seemed weaker in males than in females.

Setting standards for medically-based running analysis

Setting standards for medically based running analyses is necessary to ensure that runners receive a high-quality service from practitioners. Medical and training history, physical and functional tests, and motion analysis of running at self-selected and faster speeds are key features of a comprehensive analysis. Self-reported history and movement symmetry are critical factors that require follow-up therapy or long-term management. Pain or injury is typically the result of a functional deficit above or below the site along the kinematic chain.

Association of navicular drop and selected lower-limb biomechanical measures during the stance phase of running

There is evidence to suggest that navicular drop measures are associated with specific lower-extremity gait biomechanical parameters. The aim of this study was to examine the relationship between navicular drop and a) rearfoot eversion excursion, b) tibial internal rotation excursion, c) peak ankle inversion moment, and d) peak knee adduction moment during the stance phase of running. Sixteen able-bodied men having an average age of 28.1 (SD=5.30) years, weight of 81.5 (SD=10.40) kg, height of 179.1 (SD=5.42) cm volunteered and ran barefoot at 170 steps/minute over a force plate. Navicular drop measures were negatively correlated with tibial internal rotation excursion (r=-0.53, P=.01) but not with rearfoot eversion excursion (r=-0.19; P=.23). Significant positive correlations were found between navicular drop and peak knee adduction moment (r=.62, P<.01) and peak ankle inversion moment (r=.60, P<.01). These findings suggest that a low navicular drop measure could be associated with increasing tibial rotation excursion while high navicular drop measure could be associated with increased peak ankle and knee joint moments. These findings indicate that measures of navicular drop explained between 28% and 38% of the variability for measures of tibial internal rotation excursion, peak knee adduction moment and peak ankle inversion moments.

Reliability of a new supination resistance measurement device and validation of the manual supination resistance test

BACKGROUND

Kinematic observations are inconsistent in predicting lower-extremity injury risk, and research suggests that kinetic variables may be more important in this regard. Before kinetics can be prospectively investigated, we need reliable ways of measuring them clinically. A measurement instrument was manufactured that closely mirrors a manual test used to clinically estimate supination resistance force. The reliability of the instrument and the validity of the clinical test were investigated.

METHODS

The left feet of 26 healthy individuals (17 men and 9 women; mean ± SD age, 25.9 ± 9.2 years; mean ± SD weight, 77.7 ± 13.3 kg) were assessed. Foot Posture Index (FPI-6), manual supination resistance, and machine supination resistance were measured. Intrarater and interrater reliability of all of the measurements were calculated. Correlations of the supination resistance measured by the device with FPI-6, the manual supination resistance test, and body weight were investigated.

RESULTS

Interrater reliability of all of the measurements was generally poor. The supination resistance machine correlated highly with the manual supination test for the rater experienced with its use. Supination resistance measurements correlated poorly with the FPI-6 and weakly with body weight.

CONCLUSIONS

The supination resistance machine was shown to have sufficient limits of agreement for the study, but improvements need to be made for more meaningful research going forward. In this study, the force required to supinate a foot was independent of its posture, and approximately 12% of it was explained by body weight. Further work is required with a much larger sample size to build regression models that sufficiently predict supination resistance force and that will be of clinical use. The manual supination test is a valid clinical test for clinicians experienced in its use.

Dose-response effects of customised foot orthoses on lower limb kinematics and kinetics in pronated foot type

Despite the widespread use of customised foot orthoses (FOs) for the pronated foot type there is a lack of reliable information on the dose-response effect on lower limb mechanics. This study investigated these effects in subjects with normal and pronated foot types. Customised FOs were administered to 12 participants with symptomatic pronated foot type and 12 age and gender matched controls. A computer-aided design (CAD) software was used to design nine FOs per participant with dose incrementally changed by varying only the rearfoot post angle. This was done in 2° increments from 6° lateral to 10° medial posting. A 3D printing method was used to manufacture the FOs. Quantification of the dose-response effect was performed using three-dimensional gait analyses for selected rearfoot and knee kinematics and kinetics. Under these experimental conditions, significant and linear effects of posting were seen for the peak (p<0.001) and mean (p<0.001) rearfoot eversions, peak (p=0.003) and mean (p<0.001) ankle eversion moments and peak (p=0.017) and mean (p=0.005) knee adduction moment variables. Group effects were observed for the peak (p=0.007) and mean (p=0.007) forefoot abduction and for the peak (p=0.007) knee adduction moment. A significant interaction between posting and group was seen for internal tibial rotation (p=0.004). These data indicate that a dose-response effect, with a linear trend for both the rearfoot and knee, exists for customised FOs used to treat pronated foot type.

Medially posted insoles consistently influence foot pronation in runners with and without anterior knee pain

Anterior knee pain (AKP) is a common injury among runners and effectively treated with posted insoles and foot orthotics. While clinically effective, the underlying biomechanical mechanisms that bring about these improvements remain debatable. Several methodological factors contribute to the inconsistent biomechanical findings, including errors associated with removing and reattaching markers, inferring foot motion from markers placed externally on a shoe, and redefining segmental coordinate systems between conditions. Therefore, the purpose of this study was to evaluate the influence of medially posted insoles on lower extremity kinematics in runners with and without AKP while trying to limit the influence of these methodological factors. Kinematics of 16 asymptomatic and 17 runners with AKP were collected while running with and without insoles. Reflective markers were attached to the surface of the calcaneus and kept in place (as opposed to detached) between conditions, eliminating the error associated with reattaching markers and redefining segmental coordinate systems. Using these methods, no significant interactions between insole and injury and the main effect of injury were detected (p>0.05); therefore, means were pooled across injury. Insoles, on average, reduced peak eversion by 3.6° (95% confidence interval -2.9° to -4.3°), peak eversion velocity by 53.2°/s (95% confidence interval -32.9 to -73.4) and eversion range of motion by 1.33 (95% confidence interval -0.8 to -1.9). However, while insoles systematically reduced eversion variables, they had small influences on the transverse plane kinematics of the tibia or knee, indicating that they may bring about their clinical effect by influencing other variables.

The Effects of Rearfoot Position on Lower Limb Kinematics during Bilateral Squatting in Asymptomatic Individuals with a Pronated Foot Type

Clinicians frequently assess movement performance during a bilateral squat to observe the biomechanical effects of foot orthotic prescription. However, the effects of rearfoot position on bilateral squat kinematics have not been established objectively to date. This study aims to investigate these effects in a population of healthy adults with a pronated foot type. Ten healthy participants with a pronated foot type bilaterally (defined as a navicular drop >9mm) performed three squats in each of three conditions: barefoot, standing on 10mm shoe pitch platforms and standing on the platforms with foam wedges supporting the rearfoot in subtalar neutral. Kinematic data was recorded using a 3D motion analysis system. Between-conditions changes in peak joint angles attained were analysed. Peak ankle dorsiflexion (p=0.0005) and hip abduction (p=0.024) were significantly reduced, while peak knee varus (p=0.028) and flexion (p=0.0005) were significantly increased during squatting in the subtalar neutral position compared to barefoot. Peak subtalar pronation decreased by 5.33° (SD 4.52°) when squatting on the platforms compared to barefoot (p=0.006), but no additional significant effects were noted in subtalar neutral. Significant changes in lower limb kinematics may be observed during bilateral squatting when rearfoot alignment is altered. Shoe pitch alone may significantly reduce peak pronation during squatting in this population, but additional reductions were not observed in the subtalar neutral position. Further research investigating the effects of footwear and the subtalar neutral position in populations with lower limb pathology is required.

Medial arch supports do not significantly alter the knee adduction moment in people with knee osteoarthritis

OBJECTIVE

This study aimed to evaluate the immediate effects of medial arch supports on indices of medial knee joint load (the peak external knee adduction moment (KAM) and knee adduction angular (KAA) impulse) and knee pain during walking in people with medial knee osteoarthritis (OA).

DESIGN

Twenty-one people with medial compartment OA underwent gait analysis in standardised athletic shoes wearing (1) no medial arch supports and (2) prefabricated medial arch supports, in random order. Outcomes were the first and second peaks in the external KAM, the KAA impulse and severity of knee pain during testing. Outcomes were compared across conditions using paired t tests (gait data) and Wilcoxon Signed Ranks test (pain data).

RESULTS

There were no significant changes in either first or second peak KAM, or in the KAA impulse, with the addition of medial arch supports (all P > 0.05). Considerable individual variation in response to the arch supports was observed across participants. There was no immediate change in knee pain during walking when medial arch supports were worn (P = 0.56).

CONCLUSIONS

This study showed no mean change in any of the measured indices of medial knee load with medial arch supports. No immediate changes in knee pain were evident.

The relationship between foot motion and lumbopelvic-hip function: a review of the literature

Excessive pronation has been implicated in the development of numerous overuse injuries of the lower limb and is suggested to cause more proximal biomechanical dysfunction. Functional foot orthoses (FFO) are frequently prescribed for lower limb injury associated with excessive foot pronation and have been demonstrated to have efficacy with specific conditions. However, the mechanism of action of FFO is largely unknown. Research investigating the kinematic and kinetic changes associated with FFO use is inconclusive. Furthermore there is a growing body of evidence suggesting that changes to muscle activity patterns in response to FFO may be responsible for their therapeutic effect. Additionally, current research suggests dysfunction of musculature of the lumbopelvic-hip complex is involved in lower extremity functional changes and is related to the development some pathologies traditionally attributed to excessive foot pronation. Evidence of temporal coupling between the hip and the foot and changes in hip muscle activity associated with FFO use further suggest a relationship between proximal and distal lower limb function. The aim of this review is to discuss the association between foot and lumbopelvic-hip complex dysfunction and injury, assess the evidence for functional changes to lower limb and lumbopelvic-hip function with FFO use and finally to discuss the potential for changes to hip musculature activation with FFO use to influence distal mechanics and produce a therapeutic benefit.

Effects of medially wedged foot orthoses on knee and hip joint running mechanics in females with and without patellofemoral pain syndrome

We examined the effects of medially wedged foot orthoses on knee and hip joint mechanics during running in females with and without patellofemoral pain syndrome (PFPS). We also tested if these effects depend on standing calcaneal eversion angle. Twenty female runners with and without PFPS participated. Knee and hip joint transverse and frontal plane peak angle, excursion, and peak internal knee and hip abduction moment were calculated while running with and without a 6° full-length medially wedged foot orthoses. Separate 3-factor mixed ANOVAs (group [PFPS, control] x condition [medial wedge, no medial wedge] x standing calcaneal angle [everted, neutral, inverted]) were used to test the effect of medially wedged orthoses on each dependent variable. Knee abduction moment increased 3% (P = .03) and hip adduction excursion decreased 0.6° (P < .01) using medially wedged foot orthoses. No significant group x condition or calcaneal angle x condition effects were observed. The addition of medially wedged foot orthoses to standardized running shoes had minimal effect on knee and hip joint mechanics during running thought to be associated with the etiology or exacerbation of PFPS symptoms. These effects did not appear to depend on injury status or standing calcaneal posture.

Effect of ankle-foot orthotic devices on foot kinematics in Stage II posterior tibial tendon dysfunction

BACKGROUND

Data are limited on the various orthotic devices available for patients with Stage II posterior tibial tendon dysfunction (PTTD). Foot kinematics observed while walking with an orthotic device are hypothesized to be associated with clinical outcomes and could be used to refine future device designs.

METHODS

Fifteen subjects (age, 63.6 ± 6.8 years) with Stage II PTTD walked in the lab under four conditions: (1) shoe only (control condition), (2) shoe with a custom solid AFO (Arizona Co, Mesa, AZ), (3) shoe with a custom articulated AFO (Arizona Co, Mesa, AZ), and (4) shoe with an off-the-shelf AFO (AirLift, DJ Orthopedics). Kinematic data were collected to determine the degree of hindfoot inversion, forefoot plantarflexion (reflective of raising the MLA), and forefoot adduction associated with each condition.

RESULTS

The custom articulated device was associated with greater hindfoot inversion compared to the shoe only condition at loading response (p = 0.002), mid-stance (p < 0.001), and terminal stance (p = 0.02). The custom articulated device, custom solid device, and off-the-shelf device were associated with greater forefoot plantarflexion compared to the shoe only condition across all four phases of stance. There were no differences between any of the devices and the shoe condition associated with forefoot adduction.

CONCLUSION

The custom devices were associated with greater hindfoot inversion and forefoot plantarflexion compared to walking with only a shoe, while the off-the-shelf device was associated with forefoot plantarflexion but no change in hindfoot motion. None of the devices corrected forefoot abduction compared to the shoe only condition.

CLINICAL RELEVANCE

The current biomechanical data may aid in understanding the clinical outcomes seen using these devices as well as provide data to support new designs.

Foot orthoses: a review focusing on kinematics

Orthoses have been broadly used by clinicians to treat mechanical misalignments, such as abnormal foot pronation. As such, the influences of orthoses on lower-limb kinematics have been studied numerous times, with many articles reporting nonsystematic results; the aim of this review, therefore, was to examine the recognized effects of foot orthoses on lower-limb kinematics. The findings from this review suggest that foot orthoses seem to have certain generic and common effects on the lower limb when designed to control rearfoot pronation. We also discuss the possible reasons behind the lack of consistent results between studies. Based on the findings, a list of recommendations is presented for future research on foot orthoses to facilitate comparisons between studies and enable the scientific and clinical communities to better comprehend the effects that these variables might have on the kinematics and, possibly, the treatment outcomes.

Changes in multi-segment foot biomechanics with a heat-mouldable semi-custom foot orthotic device

Background

Semi-custom foot orthoses (SCO) are thought to be a cost-effective alternative to custom-made devices. However, previous biomechanical research involving either custom or SCO has only focused on rearfoot biomechanics. The purpose of this study was therefore to determine changes in multi-segment foot biomechanics during shod walking with and without an SCO. We chose to investigate an SCO device that incorporates a heat-moulding process, to further understand if the moulding process would significantly alter rearfoot, midfoot, or shank kinematics as compared to a no-orthotic condition. We hypothesized the SCO, whether moulded or non-moulded, would reduce peak rearfoot eversion, tibial internal rotation, arch deformation, and plantar fascia strain as compared to the no-orthoses condition.

Methods

Twenty participants had retroreflective markers placed on the right limb to represent forefoot, midfoot, rearfoot and shank segments. 3D kinematics were recorded using an 8-camera motion capture system while participants walked on a treadmill.

Results

Plantar fascia strain was reduced by 34% when participants walked in either the moulded or non-moulded SCO condition compared to no-orthoses. However, there were no significant differences in peak rearfoot eversion, tibial internal rotation, or medial longitudinal arch angles between any conditions.

Conclusions

A semi-custom moulded orthotic does not control rearfoot, shank, or arch deformation but does, however, reduce plantar fascia strain compared to walking without an orthoses. Heat-moulding the orthotic device does not have a measurable effect on any biomechanical variables compared to the non-moulded condition. These data may, in part, help explain the clinical efficacy of orthotic devices.

Gender and Foot Orthotic Device Effect on Frontal Plane Hip Motion During Landing From a Vertical Jump

Excessive hip motion has been linked to lower extremity pathology. Foot orthoses are commonly used to control motion within lower extremity joints when lower extremity pathology and dysfunction are present. Few studies have investigated the effect of foot orthoses on hip angular kinematics during functional activities. Eighteen females and 18 males performed a vertical jump with and without a prefabricated foot orthoses to determine the biomechanical effect of foot orthoses on hip kinematics when landing from a jump. Data collection included three-dimensional motion analysis of the lower extremity. Pairedttests were performed to determine if differences existed within genders with and without foot orthoses. At the hip joint, there was significantly less hip adduction motion in the foot orthoses condition as compared with the no foot orthoses condition in females (p< .05). There were no differences between foot orthoses conditions in males. Females appear to have a different proximal response to foot orthoses when landing from a forward jump than males.

Measures of range of motion and strength among healthy women with differing quality of lower extremity movement during the lateral step-down test

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To determine the association between hip and ankle range-of-motion measures, as well as measures of hip muscle strength, with measures of quality of lower extremity movement, as assessed visually during the lateral step-down test in healthy women.

BACKGROUND

Altered lower extremity movement pattern consisting of excessive femoral adduction and internal rotation, leading to excessive knee valgus alignment, is associated with increased risk of knee ligament injury, as well as patellofemoral pain syndrome. Previous investigations of lower extremity kinematics, using 3-dimensional motion analysis systems, document an inconsistent association between hip muscle strength and lower extremity movement pattern. Currently, it is unknown whether differences in hip muscle strength or other physical measures exist among women with differing quality of lower extremity movement as assessed by visual observation.

METHODS

Two physical therapists assessed the quality of movement during the lateral step-down among 29 healthy women (mean ± SD age, 24.3 ± 3.2 years). Subjects were instructed on the optimal movement pattern prior to performing the test. The quality of movement was categorized as "good" or "moderate," based on a previously established 6-point scale. Several measures of hip strength (handheld dynamometer) and hip and ankle range of motion (fluid-filled inclinometer and universal goniometer) were also assessed. Differences in strength and range-of-motion measures between women with good and women with moderate quality of movement were assessed with a Mann-Whitney U test.

RESULTS

Both examiners found decreased ankle dorsiflexion range of motion, as measured with the knee bent (P<.05 and P<.01 for examiner 1 and 2, respectively) and in weight bearing (P<.001 and P<.01 for examiner 1 and 2, respectively) among women with a moderate quality of movement compared to women with a good quality of movement on the lateral step-down test.

CONCLUSION

Following receipt of instructions on optimal lower extremity movement pattern, women who demonstrate a moderate quality of movement, as assessed visually during the lateral step-down test, exhibit decreased ankle dorsiflexion range of motion compared to women with a good quality of movement. Clinicians should consider evaluating ankle dorsiflexion range of motion when observing an altered lower extremity movement pattern during the lateral step-down test.

Comparative biomechanical effectiveness of over-the-counter devices for individuals with a flexible flatfoot secondary to forefoot varus

OBJECTIVES

Evaluate effects of a new off-the-shelf insert on frontal plane foot biomechanics and compare effectiveness of the new and an existing off-the-shelf insert and a motion-control shoe in neutralizing frontal plane foot biomechanics.

DESIGN

Descriptive.

SETTING

Biomechanics laboratory.

PARTICIPANTS

Fifteen uninjured subjects with a flexible flatfoot secondary to forefoot varus.

ASSESSMENT OF RISK FACTORS

Three-dimensional kinematic and kinetic data were collected as subjects walked and jogged at their self-selected speed while wearing a motion-control running shoe, the shoe with a new off-the-shelf insert, and the shoe with an existing off-the-shelf insert.

MAIN OUTCOME MEASURES

Frontal plane kinematics and rearfoot kinetics were evaluated during stance. Statistical analysis was performed using a repeated measures analysis of variance and Student-Newman-Keuls post hoc tests (α ≤ 0.05).

RESULTS

The new insert and motion-control shoe placed the forefoot in a less-everted position than the existing off-the-shelf insert during walking. There were no differences in forefoot kinematics during jogging, nor were there differences in rearfoot motion during walking or jogging. The rearfoot eversion moment was significantly lower with the new off-the-shelf insert compared with the motion-control shoe and the existing insert during walking and jogging.

CONCLUSIONS

A new off-the-shelf device is available that promotes more neutral frontal plane biomechanics, thus providing a theoretical rationale for using this device for injury prevention and treatment. The comparative biomechanical effectiveness of a motion-control shoe and the orthotic inserts may assist health care professionals in selecting a device to correct the flatfoot structure.

Relationships between foot type and dynamic rearfoot frontal plane motion

Background

The Foot Posture Index (FPI) provides an easily applicable, validated method for quantifying static foot posture. However there is limited evidence relating to the ability of the FPI to predict dynamic foot function. This study aimed to assess the relationship between dynamic rearfoot motion and FPI scores in pronated and normal foot types.

Methods

40 participants were recruited with equal numbers of pronated and normal foot types as classified by their FPI score. Three dimensional rearfoot motion was collected for each of the participants. Dynamic maximum rearfoot eversion was correlated with the total FPI score across all participants and within the normal and pronated foot types. Linear correlations were performed between components of the total FPI scores measuring frontal plane rearfoot position and maximum rearfoot eversion. The capacity of the total FPI score to predict maximum frontal plane motion of the rearfoot was investigated using linear regression analysis.

Results

The correlation between the total FPI score and maximum rearfoot eversion was strongly positive (r = 0.92, p < 0.05). Correlation performed on data subsets demonstrated the pronated foot type (FPI = +6 to +9) and maximum rearfoot eversion angle were more strongly positively correlated (r = 0.81, p < 0.05) than the normal foot type (FPI = 0 to +5) and maximum rearfoot eversion (r = 0.76, p < 0.05). Correlations between frontal plane rearfoot FPI score and frontal plane motion during gait were strongly positive, (r = 0.79 p < 0.05 pronated group, r = 0.71 p < 0.05 normal group), however were less strong than the total FPI score and rearfoot motion. Linear regression analysis demonstrated a significant and strong relationship between the total FPI score and maximum rearfoot eversion (r² = 0.85, p < 0.001).

Conclusions

The results of this study suggest the FPI has strong predictive ability for dynamic rearfoot function. This will assist in clinical screening and research by allowing easy classification by functional foot type. Positive correlations between frontal plane rearfoot measurements and maximum rearfoot eversion suggest the FPI may identify dominant planar components of dynamic rearfoot motion and warrants further investigation.

Foot orthotic devices decrease transverse plane motion during landing from a forward vertical jump in healthy females

The use of foot orthoses has been evaluated during a variety of functional activities. Twelve college-aged active females wore two types of foot orthoses and performed a vertical jump to determine the biomechanical effect of the orthoses on lower extremity transverse plane movement during landing. Data collection included three-dimensional analysis of the tibia, knee, and hip. A repeated-measures ANOVA was performed to determine the differences between no orthoses, over-the-counter, and custom-made orthoses with transverse plane motion. At the hip joint, there was significantly less internal rotation (p < .05) in the over-the-counter condition as compared with the no orthoses condition. There was significantly less tibial internal rotation (p < .05) in the custom-made condition as compared with no orthoses. Over-the-counter devices decreased transverse plane motion at the hip, whereas custom-made devices decreased transverse plane motion of the tibia.

Changes in running kinematics and kinetics in response to a rockered shoe intervention

BACKGROUND

A suggested link between ambulatory mechanics and injury development has resulted in significant interest the development of footwear to change locomotion patterns. The purpose of this study was to test the hypothesis that there will be significant changes in the kinematics and kinetics at the ankle and minimal changes at the knee and hip in the mechanics of running in a shoe with a sagittal plane curvature relative to a flat soled shoe.

METHODS

During running 3-D lower extremity kinematics and kinetics for 19 healthy volunteers were quantified using an optoelectronics system and a force plate. Data were collected for a flat sole conventional shoe (New Balance 658 (Control)) and a shoe with a rounded sole in the sagittal plane (Masai Barefoot Technologies (MBT)). Data were compared for the two shoe conditions using paired Student t-tests (alpha=0.05).

FINDINGS

The ankle dorsi-flexion angles at heel-strike and mid-stance were greater, while the ankle plantar and dorsi-flexion moments and peak ankle joint power were significantly lower with the MBT relative to the control (P<0.05). Decreases in the first medial GRF peak and the peak anterior GRF peak were also found for running in the MBT shoe.

INTERPRETATION

Despite a major difference in sole geometry, accommodations to the rockered sole were found only at the ankle. These results suggest changes in ankle kinematics and kinetics may be used to minimize the effect of changes in sole rocker on limb dynamics. Thus, changes in shoe rocker may offer potential therapeutic opportunities for running related conditions at the ankle without substantial risk to the knee or hip.

Choosing among 3 ankle-foot orthoses for a patient with stage II posterior tibial tendon dysfunction

STUDY DESIGN

Case report.

BACKGROUND

No head-to-head comparisons of different orthoses for patients with stage II posterior tibial tendon dysfunction (PTTD) have been performed to date. Additionally, the cost of orthoses varies considerably, thus choosing an effective orthosis that is affordable to the patient is largely a trial-and-error process.

CASE DESCRIPTION

A 77-year-old woman was seen with complaints of abnormal foot posture ('my foot is out'), minimal medial foot and ankle pain, and a 3-year history of conservatively managed stage II PTTD. The patient was not able to complete 1 single-limb heel rise on the involved side, while she could complete 3 on the uninvolved side. Ankle strength testing revealed a mild to moderate loss of plantar flexor strength (20%-31% deficit on the involved side), combined with a 22% deficit in isometric ankle inversion and forefoot adduction strength. To assist this patient in managing her flatfoot posture and PTTD, 3 orthoses were considered: an off-the-shelf ankle-foot orthosis (AFO), a custom solid AFO, and a custom articulated AFO. The patient's chief complaint was partly cosmetic (ìmy foot is outî). As decreasing flatfoot kinematics may unload the tibialis posterior muscle, thus prevent the progression of foot deformity, the primary goal of orthotic intervention was to improve flatfoot kinematics. Given the difficulties in clinical approaches to evaluating flatfoot kinematics, a quantitative gait analysis, using a multisegment foot model, was used.

OUTCOMES

In the frontal plane, all 3 orthoses were associated with small changes toward hindfoot inversion. In the sagittal plane, between 2.7 degrees and 6.1 degrees , greater forefoot plantar flexion (raising the medial longitudinal arch) occurred. There were no differences among the orthoses on hindfoot inversion and forefoot plantar flexion. In the transverse plane, the off-the-shelf design was associated with forefoot abduction, the custom solid orthosis was associated with no change, and the custom articulated orthosis was associated with forefoot adduction.

DISCUSSION

Based on gait analysis, the higher-cost custom articulated orthosis was chosen as optimal for the patient. This custom articulated orthosis was associated with the greatest change in flatfoot deformity, assessed using gait analysis. The patient felt it produced the greatest correction in foot deformity. Reducing flatfoot deformity while allowing ankle movement may limit progression of stage II PTTD.

LEVEL OF EVIDENCE

Therapy, level 4.

Influence of running shoe midsole composition and custom foot orthotic intervention on lower extremity dynamics during running

The purpose of this study was to analyze the influence of varying running shoe midsole composition on lower extremity dynamics with and without a custom foot orthotic intervention. Three-dimensional dynamics were collected on 12 female runners who had completed 6 weeks of custom foot orthotic therapy. Participants completed running trials in 3 running shoe midsole conditions-with and without a custom foot orthotic intervention. Results from the current study revealed that only maximum rearfoot eversion velocity was influenced by the midsole durometer of the shoe. Maximum rearfoot eversion velocity was significantly decreased for the hard shoe compared with the soft shoe. However, the orthotic intervention in the footwear led to significant decreases in several dynamic variables. The results suggest that the major component influencing the rearfoot dynamics was the orthotic device and not the shoe composition. In addition, data suggest that the foot orthoses appear to compensate for the lesser shoe stability enabling it to function in a way similar to that of a shoe of greater stability.

Effects of the AirLift PTTD brace on foot kinematics in subjects with stage II posterior tibial tendon dysfunction

STUDY DESIGN

Experimental laboratory study.

OBJECTIVES

To investigate the effect of inflation of the air bladder component of the AirLift PTTD brace on relative foot kinematics in subjects with stage II posterior tibial tendon dysfunction (PTTD).

BACKGROUND

Orthotic devices are commonly recommended in the conservative management of stage II PTTD to improve foot kinematics.

METHODS AND MEASURES

Ten female subjects with stage II PTTD walked in the laboratory wearing the AirLift PTTD brace during 3 testing conditions (air bladder inflation to 0, 4, and 7 PSI [SI equivalent: 0, 27,579, and 48,263 Pa]). Kinematics were recorded from the tibia, calcaneus (hindfoot), and first metatarsal (forefoot), using an Optotrak motion analysis system. Comparisons were made between air bladder inflation and the 0-PSI condition for each of the dependent kinematic variables (hindfoot eversion, forefoot abduction, and forefoot dorsiflexion).

RESULTS

Greater hindfoot inversion was observed with air bladder inflation during the second rocker (mean, 1.7 degrees; range, -0.7 degrees to 6.1 degrees). Less consistent changes in forefoot plantar flexion and forefoot adduction occurred with air bladder inflation. The greatest change toward forefoot plantar flexion was observed during the third rocker (mean, 1.4 degrees; range, -3.8 degrees to 3.9 degrees). The greatest change towards adduction was observed during the third rocker (mean, 2.3 degrees; range, -3.4 degrees to 6.5 degrees).

CONCLUSIONS

On average, the air bladder component of the AirLift PTTD brace was successful in reducing the amount of hindfoot eversion observed in subjects with stage II PTTD; however, the effect on forefoot motion was more variable. Some subjects tested had marked improvement in foot kinematics, while 2 subjects demonstrated negative results. Specific foot characteristics are hypothesized to explain these varied results.

A comparison of rearfoot motion control and comfort between custom and semicustom foot orthotic devices

BACKGROUND

Motion control and comfort are primary objectives in orthotic intervention. Semicustom orthotic devices have been presented as a more cost-effective solution than custom orthotic devices. However, no studies have compared their function or comfort to that of custom orthotic devices.

METHODS

Nineteen uninjured runners were fitted for custom and semicustom orthotic devices. Subjects underwent an instrumented gait analysis of running and walking in no-orthotic, custom orthotic, and semicustom orthotic conditions. Subjects completed visual analog scales for the custom and semicustom orthotic conditions. One-way repeated measures analyses of variance were performed on the rearfoot variables of peak eversion, eversion excursion, eversion duration, and eversion velocity. Two-tailed, dependent t tests were used to compare comfort.

RESULTS

Eversion excursion showed significant differences between the conditions: during running, it was reduced in the custom orthotic as compared to the no-orthotic condition; during walking, it was reduced in the semicustom orthotic as compared to both the custom and no-orthotic conditions. The custom orthotic devices were significantly more comfortable (P < .05) than the semicustom devices in the area of the edges only.

CONCLUSION

The results suggest that, in uninjured individuals, there are few differences in rearfoot motion control and comfort between the custom and semicustom orthotic devices used in this study.

Effect of foot orthoses on lower extremity kinetics during running: a systematic literature review

Background

Throughout the period of one year, approximately 50% of recreational runners will sustain an injury that disrupts their training regimen. Foot orthoses have been shown to be clinically effective in the prevention and treatment of several running-related conditions, yet the physical effect of this intervention during running remains poorly understood. The aim of this literature review was therefore to evaluate the effect of foot orthoses on lower extremity forces and pressure (kinetics) during running.

Methods

A systematic search of electronic databases including Medline (1966-present), CINAHL, SportDiscus, and The Cochrane Library occurred on 7 May 2008. Eligible articles were selected according to pre-determined criteria. Methodological quality was evaluated by use of the Quality Index as described by Downs & Black, followed by critical analysis according to outcome variables.

Results

The most widely reported kinetic outcomes were loading rate and impact force, however the effect of foot orthoses on these variables remains unclear. In contrast, current evidence suggests that a reduction in the rearfoot inversion moment is the most consistent kinetic effect of foot orthoses during running.

Conclusion

The findings of this review demonstrate systematic effects that may inform the direction of future research, as further evidence is required to define the mechanism of action of foot orthoses during running. Continuation of research in this field will enable targeting of design parameters towards biomechanical variables that are supported by evidence, and may lead to advancements in clinical efficacy.