The effect of foot wedging on electromyographic activity in the erector spinae and gluteus medius muscles during walking

Immediate Effect of Simulated High Heels on Pelvic and Spinal Posture in Healthy Young Subjects: A Cross-Sectional Study

Background Investigations regarding the role of high-heeled shoes in the alteration of the spinopelvic profile attempted to identify a correlation with pain in the lower back. Conclusions from these studies, however, are controversial. In authors knowledge no studies were carried out to investigate the effect of heels on male population, which has been overlooked due to gender-related customs. Research question What is the immediate effect of the height of heels on the sagittal back profile (trunk inclination (TI), pelvic inclination, lordotic lumbar angle (ITL-ILS), kyphotic dorsal angle, lumbar arrow, and cervical arrow) in females and males, not used to wearing high-heeled shoes? Methods One hundred healthy young adult subjects were enrolled. Three were excluded. The remaining 97 subjects (48 female and 49 male) underwent a three-dimensional analysis of the posterior surface of the trunk, using rasterstereography. The spinopelvic profile in the barefoot condition, and with the heel raised by 3 and 7 cm, was recorded. To evaluate the reproducibility of the measure, the neutral evaluation was repeated twice in 23 subjects (13 males, 10 females). Results The change of heel height did not show statistically significant differences for any of the variables used; instead, significant differences were found stratifying the results according to the sex of the subjects tested. Test-retest evaluation in the neutral condition showed no significant differences using the Student's t-test (p > 0.05). Repeatability was excellent and significant for all data used (minimum TI r = 0.85, maximum ITL-ILS r = 0.97). Significance Studying the effect of heels on the spino-pelvic profile also in the male population is crucial for promoting gender-inclusive healthcare, enhancing occupational health practices and developing possible preventive measures. Nevertheless, in the sample of females and males evaluated in this study, the different heights of heel lift did not immediately induce significant changes in pelvis and spine posture. If there is therefore a correlation between low-back pain and the use of heels, it should not reasonably be sought in the immediate change of the spino-pelvic profile caused by raising the heels. However, the variables analyzed differed according to sex.

Coactivation of the Pelvic Floor and Gluteus Medius Muscles While Walking and Running in Female Runners

(1) Background: Pelvic-floor-muscle (PFM) activation acts synergistically with multiple muscles while performing functional actions in humans. The purpose of this study was to characterize the activity of the PFMs and gluteus medius (GM) while walking and running in physically active nulliparous females. (2) Methods: The peak and average amplitude of maximal voluntary contractions (MVCs) during 60 s of walking (5 and 7 km/h) and running (9 and 11 km/h) were measured with electromyography of the GM and PFMs in 10 healthy female runners. (3) Results: The activation of both muscles increased (p < 0.001) while walking and running. The MVC of the GM was reached when walking and tripled when running, while the PFMs were activated at half their MVC when running. The global ratio of the GM (75.3%) was predominant over that of the PFMs (24.6%) while static and walking. The ratio reached 9/1 (GM/PFM) while running. (4) Conclusion: The GM and PFMs were active while walking and running. The GM's MVC tripled at high speeds, while the PFMs reached only half of their maximum contraction.

Changes in the Activity of the Erector Spinae and Gluteus Medius Muscles with the Presence of Simulated Lower Limb Dysmetria

(1) Background: Leg length discrepancy (LLD), regardless of its origin, is a very common pathology that can contribute to low back pain. Various authors have pointed out its relationship with the lack of activation of both the gluteus medius (GM) and the ipsilateral erector spinae (ES). The purpose of this study was to identify the activation of the ES and GM with different simulated LLDs, correlating this activation with LBP. In turn, we evaluated whether ES and GM activity has an effect on jumping ability using a CMJ test. (2) Method: A sample of healthy subjects was selected to whom an artificial LLD was applied using 0.5, 1, and 1.5 cm insoles. These three heights were measured using EMG while the subjects walked and performed a counter movement jump (CMJ). The measurements of the insole heights were carried out in random order using a Latin square. Muscle activation patterns were recorded for 30 s at each of the insole heights while the patients walked at 5.7 km/h and they were compared with the maximum voluntary contraction (MVC), both on the ipsilateral and contralateral sides. These muscles were then measured under the same circumstances during the performance of the CMJ. (3) Results: We found statistically significant differences in the flight heights in both the CMJ and DJ. In the comparison, significant differences were found in the flight heights of the CMJ and the DJ using the 5 mm insoles, and in the case of the DJ, also without insoles, with respect to the MVC. We found statistically significant differences in the activation of the GM with the differences in insoles, but not in the activation of the Es in relation to the different insole heights. (4) Conclusions: Insoles of different heights caused activation differences in the medius on the side where the insoles were placed. We can relate this difference in activation to LBP. In relation to the ES, no significant differences were found in the activation of the ipsilateral side of the insole.

Effects of Artificially Induced Leg Length Discrepancy on Treadmill-Based Walking and Running Symmetry in Healthy College Students: A Lab-Based Experimental Study

Leg length discrepancy (LLD) is a common postural deviation of musculoskeletal origin, which causes compensatory reactions and often leads to injury. The aim of the study was to investigate the effect of artificially induced LLD on gait symmetry by means of the spatiotemporal gait parameters and ground reaction forces (GRFs) using a treadmill equipped with capacitive sensors (instrumented) as well as the EMG activity of trunk and hip muscles during walking and running. Twenty-six healthy male and female college students were required to perform two sets of four 2.5-min walking and running trials on an instrumented treadmill at 5.6 and 8.1 km·h-1, respectively, without (0) and with 1, 2, and 3 cm LLD implemented by wearing a special rubber shoe. Statistical analysis was performed using one-way repeated measures or a mixed-design ANOVA. Most spatiotemporal gait parameters and GRFs demonstrated an increase or decrease as LLD increased either on the short-limb or the long-limb side, with changes becoming more apparent at ≥1 cm LLD during walking and ≥2 cm LLD during running. The EMG activity of trunk and hip muscles was not affected by LLD. Our findings showed that gait symmetry in terms of treadmill-based spatiotemporal parameters of gait and GRFs is affected by LLD, the magnitude of which depends on the speed of locomotion.

Decoding Hip Muscle Activation: A Comparative Electromyographic Analysis of Turn-Out Bent Knee Pulse and Single-Leg Banded Glute Bridge Exercises in Healthy Female Subjects

Individuals with lower extremity injuries and back pain may exhibit weakness and stiffness in important muscles such as the gluteus maximus and external hip rotators. To aid clinicians in understanding the impact of exercises on factors like stability, endurance, and strength, electromyography (EMG) examination can be employed to monitor muscle activation. In this investigation, the EMG activity of the gluteus maximus and medius were compared between two exercises: the turn-out bent knee pulse and the single-leg banded glute bridge. The study enrolled a group of 64 healthy young women, aged 19 to 24 years. The raw data collected were standardized and represented as a percentage of maximum voluntary isometric contraction (%MVIC). To assess the reliability of the EMG recordings, the test-retest analysis was performed using the intraclass correlation coefficient (ICC3,1). Statistical analysis involved conducting a one-way ANOVA to compare the EMG amplitudes between the two exercises. Remarkably, the results demonstrated a significantly higher EMG signal amplitude during the single-leg banded glute bridge exercise (mean ± SD: 90 ± 28% MVIC) when compared to the turn-out bent knee pulse exercise (mean ± SD: 70 ± 15% MVIC) (F = 16.584, p = 0.001). The study found that the single-leg banded glute bridge exercise had a significantly higher EMG signal amplitude compared to the turn-out bent knee pulse exercise. This suggests that the single-leg banded glute bridge exercise may be more effective in strengthening the gluteus maximus and medius muscles. Overall, this study highlights the importance of targeted muscle training in rehabilitation protocols and the use of EMG examination to monitor muscle activation.

Investigating the effect of sand training on running mechanics in individuals with anterior cruciate ligament reconstruction and pronated feet

BACKGROUND

Running on sand could be a method for the rehabilitation of individuals with anterior cruciate ligament reconstruction and pronated feet. However, there is a lack of knowledge about the effects of running on sand on running biomechanics and muscle activities.

RESEARCH QUESTION

What is the effect of sand training on running mechanics in individuals with anterior cruciate ligament reconstruction and pronated feet?

METHODS

Twenty-eight adult males with anterior cruciate ligament reconstruction and pronated feet were divided into two equal groups (intervention and active control groups). Participants were asked to run at a constant speed of ∼3.2 m/s over an 18 m runway, respectively. Ground reaction forces were recorded using a Bertec force plate. Muscle activities were recorded using a surface bipolar electromyography system.

RESULTS

In intervention group but not control group, post-hoc analysis demonstrated significantly longer time-to-peak of impact vertical ground reaction force at post-test than that pre-test (p = 0.047). In intervention group but not control group, post-hoc analysis demonstrated significant decreases of semitendinosus activities during push-off at post-test compared with the pre-test (p = 0.005).

SIGNIFICANCE

Sand training improved time-to-peak of ground reaction forces (e.g., time-to-peak of peak of impact vertical ground reaction force) and muscle activities (e.g., semitendinosus activities) in adult males with anterior cruciate ligament reconstruction and pronated feet.

Effects of Running on Sand vs. Stable Ground on Kinetics and Muscle Activities in Individuals With Over-Pronated Feet

Background: In terms of physiological and biomechanical characteristics, over-pronation of the feet has been associated with distinct muscle recruitment patterns and ground reaction forces during running.

Objective: The aim of this study was to evaluate the effects of running on sand vs. stable ground on ground-reaction-forces (GRFs) and electromyographic (EMG) activity of lower limb muscles in individuals with over-pronated feet (OPF) compared with healthy controls.

Methods: Thirty-three OPF individuals and 33 controls ran at preferred speed and in randomized-order over level-ground and sand. A force-plate was embedded in an 18-m runway to collect GRFs. Muscle activities were recorded using an EMG-system. Data were adjusted for surface-related differences in running speed.

Results: Running on sand resulted in lower speed compared with stable ground running (p < 0.001; d = 0.83). Results demonstrated that running on sand produced higher tibialis anterior activity (p = 0.024; d = 0.28). Also, findings indicated larger loading rates (p = 0.004; d = 0.72) and greater vastus medialis (p < 0.001; d = 0.89) and rectus femoris (p = 0.001; d = 0.61) activities in OPF individuals. Controls but not OPF showed significantly lower gluteus-medius activity (p = 0.022; d = 0.63) when running on sand.

Conclusion: Running on sand resulted in lower running speed and higher tibialis anterior activity during the loading phase. This may indicate alterations in neuromuscular demands in the distal part of the lower limbs when running on sand. In OPF individuals, higher loading rates together with greater quadriceps activity may constitute a proximal compensatory mechanism for distal surface instability.

Long-term training on sand changes lower limb muscle activities during running in runners with over-pronated feet

BACKGROUND

Running on sand could be a promising exercise intervention for the treatment of over-pronated feet. However, there is a lack of knowledge about the effects of running on sand on muscle activities. Therefore, this study aims to evaluate the long-term effects of running on sand on the activities of selected lower limb muscles in individuals with OPF compared with healthy controls.

METHODS

Sixty recreational adult male runners with over-pronated feet (foot posture index > 10) were divided into two equal groups (intervention and control). Participants ran barefoot at a pre-defined speed (⁓3.3 m/s) over level stable ground both before and after long-term training on the sand. Muscle activities were recorded using a surface bipolar electromyography system.

RESULTS

For the intervention group, we found a reduced foot posture index (p < 0.001; d = 2.00) and significant group-by-time interactions for gluteus medius activity during the mid-stance phase (p < 0.028; d = 0.59). Significantly higher gluteus medius activity (p = 0.028, d = 0.569) was found during the post-test. We also observed significant group-by-time interactions for medial gastrocnemius activity during the push-off phase (p < 0.041; d = 0.54). Significantly larger medial gastrocnemius activity (p = 0.041; d = 0.636) was found during the post-test compared to the pre-test.

CONCLUSIONS

Long-term running on sand resulted in reduced pronation, increased medial gastrocnemius activity, and improved frontal plane pelvic stability due to higher gluteus medius activity.

TRIAL REGISTRATION

IRCT20191211045704N1. Registered 25 February 2020. Retrospectively registered.

Effects of nail softness and stiffness with distance running shoes on ground reaction forces and vertical loading rates in male elite long-distance runners with pronated feet

BACKGROUND

To improve propulsion during running, athletes often wear spike shoes designed for training and/or competition. Running with spike shoes may cause pain and/or injuries. To address this problem, a modified spike shoe was tested. This study aimed to evaluate the effects of running with dual-versus single-stiffness spike running shoes on running mechanics in long-distance runners with pronated feet.

METHODS

Sixteen male elite (national competitive level) runners (5000 or 10,000 m) aged 28.2 ± 2.5 years with pronated feet volunteered to participate in this study. To be included, participants had to have achieved personal best race times over 5- and/or 10-km races under 17 or 34 min during official running competitions. All participants were heel strikers and had a history of 11.2 ± 4.2 years of training. For the assessment of running kinetics, a force plate was imbedded into a walkway. Running kinematics were recorded using a Vicon-motion-capture system. Nike Zoom Rival shoes (Nike, Nike Zoom Rival, USA) were selected and adapted according to spike softness and stiffness. Participants ran at a constant speed of ~4.0 m/s across the walkway with both shoe conditions in randomized order. Six trials were recorded per condition. The main outcomes included peak ground reaction forces and their time-to-peak, average and instantaneous vertical loading rates, free moments, and peak ankle eversion angles.

RESULTS

Paired t-tests revealed significantly lower lateral (p = 0.021, d = 0.95) and vertical (p = 0.010, d = 1.40) forces at heel contact during running with dual-stiffness spike shoes. Running with dual-stiffness spike shoes resulted in a significantly longer time-to-peak vertical (p = 0.004, d = 1.40) force at heel contact. The analysis revealed significantly lower average (p = 0.005, d = 0.46) and instantaneous (p = 0.021, d = 0.49) loading rates and peak negative free moment amplitudes (p = 0.016, d = 0.81) when running with dual-stiffness spike shoes. Finally, significantly lower peak ankle eversion angles were observed with dual-stiffness spike shoes (p < 0.001, d = 1.29).

CONCLUSIONS

Running in dual- compared with single-stiffness spike distance running shoes resulted in lower loading rates, free moment amplitudes, and peak ankle eversion angles of long-distance runners with pronated feet.

Are Biomechanical Features of the Foot and Ankle Related to Lumbopelvic Motor Control?

BACKGROUND

Any pathomechanical change in the foot or ankle is expected to cause adverse biomechanical effects on the lumbopelvic region. However, no objective data can be found in the literature regarding the effects of musculus transversus abdominis (mTrA) and musculus lumbar multifidus (mLM), which are effective muscles in lumbopelvic motor control, or regarding the extent of their effects.

METHODS

Sixty-four healthy young adults were assessed by a physiotherapist (C.K.) experienced in treating feet and a radiologist (Y.D.) specialized in muscular imaging. In the determination of biomechanical properties of the foot, the navicular drop test (NDT), Foot Posture Index (FPI), pedobarographic plantar pressure analysis, and isokinetic strength dynamometer measurements were used in determining the strength of the muscles around the ankle. Ultrasonographic imaging was used to determine mTrA and mLM thicknesses.

RESULTS

Significant correlation was found between NDT results and mTrA and mLM thicknesses (P < .05) and between FPI results and mTrA thicknesses (P < .05). As the peak pressure of the foot medial line increased, mTrA and mLM thicknesses decreased (P < .05). Although dorsiflexion muscle strength was also effective, mTrA and mLM thicknesses were found to increase especially as plantarflexion muscle strength increased (P < .05).

CONCLUSIONS

These results show that the biomechanical and musculoskeletal properties of the foot-ankle are associated with lumbopelvic stability.

An Endurance-Dominated Exercise Program Improves Maximum Oxygen Consumption, Ground Reaction Forces, and Muscle Activities in Patients With Moderate Diabetic Neuropathy

Background

The prevalence of diabetes worldwide is predicted to increase from 2.8% in 2000 to 4.4% in 2030. Diabetic neuropathy (DN) is associated with damage to nerve glial cells, their axons, and endothelial cells leading to impaired function and mobility.

Objective

We aimed to examine the effects of an endurance-dominated exercise program on maximum oxygen consumption (VO₂max), ground reaction forces, and muscle activities during walking in patients with moderate DN.

Methods

Sixty male and female individuals aged 45–65 years with DN were randomly assigned to an intervention (IG, n = 30) or a waiting control (CON, n = 30) group. The research protocol of this study was registered with the Local Clinical Trial Organization (IRCT20200201046326N1). IG conducted an endurance-dominated exercise program including exercises on a bike ergometer and gait therapy. The progressive intervention program lasted 12 weeks with three sessions per week, each 40–55 min. CON received the same treatment as IG after the post-tests. Pre- and post-training, VO₂max was tested during a graded exercise test using spiroergometry. In addition, ground reaction forces and lower limbs muscle activities were recorded while walking at a constant speed of ∼1 m/s.

Results

No statistically significant baseline between group differences was observed for all analyzed variables. Significant group-by-time interactions were found for VO₂max (p < 0.001; d = 1.22). The post-hoc test revealed a significant increase in IG (p < 0.001; d = 1.88) but not CON. Significant group-by-time interactions were observed for peak lateral and vertical ground reaction forces during heel contact and peak vertical ground reaction force during push-off (p = 0.001–0.037; d = 0.56–1.53). For IG, post-hoc analyses showed decreases in peak lateral (p < 0.001; d = 1.33) and vertical (p = 0.004; d = 0.55) ground reaction forces during heel contact and increases in peak vertical ground reaction force during push-off (p < 0.001; d = 0.92). In terms of muscle activity, significant group-by-time interactions were found for vastus lateralis and gluteus medius during the loading phase and for vastus medialis during the mid-stance phase, and gastrocnemius medialis during the push-off phase (p = 0.001–0.044; d = 0.54–0.81). Post-hoc tests indicated significant intervention-related increases in vastus lateralis (p = 0.001; d = 1.08) and gluteus medius (p = 0.008; d = 0.67) during the loading phase and vastus medialis activity during mid-stance (p = 0.001; d = 0.86). In addition, post-hoc tests showed decreases in gastrocnemius medialis during the push-off phase in IG only (p < 0.001; d = 1.28).

Conclusions

This study demonstrated that an endurance-dominated exercise program has the potential to improve VO₂max and diabetes-related abnormal gait in patients with DN. The observed decreases in peak vertical ground reaction force during the heel contact of walking could be due to increased vastus lateralis and gluteus medius activities during the loading phase. Accordingly, we recommend to implement endurance-dominated exercise programs in type 2 diabetic patients because it is feasible, safe and effective by improving aerobic capacity and gait characteristics.

Effects of an elastic resistance band exercise program on kinetics and muscle activities during walking in young adults with genu valgus: A double-blinded randomized controlled trial

BACKGROUND

This double-blinded randomized-controlled-trial aimed to identify the effects of an elastic band resistance training on walking kinetics and muscle activities in young adults with genu valgus.

METHODS

Forty-two male young adults aged 22.5(2.7) years with genu valgus were randomly allocated to two experimental groups. The intervention group (n = 21) conducted a 14-weeks elastic band resistance training. The control group was passive during the intervention period and received the same treatment after the post-tests. Pre and post training, ground reaction forces and lower limb muscle activities were recorded during walking.

FINDINGS

Results revealed significant group-by-time interactions for peak medial ground reaction force and time-to-peak for posterior ground reaction force in favor of the intervention group (p < 0.012; d = 0.83-3.76). Resistance training with elastic bands resulted in significantly larger peak medial ground reaction force (p < 0.001; d = 1.45) and longer time-to-peak for posterior ground reaction force (p < 0.001; d = 1.85). Finding showed significant group-by-time interactions for peak positive free moment amplitudes in favor of the intervention group (p < 0.001; d = 1.18-2.02). Resistance training resulted in a lower peak positive free moment amplitude (p = 0.001; d = 1.46). With regards to muscle activities, the analysis revealed significant group-by-time interactions for rectus femoris and gluteus medius activities during the push-off phase in favor of the intervention group (p < 0.038; d = 0.68-0.89). Resistance training induced higher rectus femoris (p = 0.038; d = 0.84) and gluteus medius (p = 0.007; d = 0.54) activities.

INTERPRETATION

This study proved the effectiveness of resistance training using elastic bands on kinetics and muscle activities during walking in male adults with genu valgus disorder. Given that this training regime is low cost, effective, and easy-to-administer, we suggest that it should be implemented as a rehabilitative or preventive means for young adults with genu valgus.

An exploratory study investigating the effect of foot type and foot orthoses on gluteus medius muscle activity

Background

Abnormal gluteus medius muscle activity is associated with a number of musculoskeletal conditions. Research investigating the effect of foot type and foot orthoses on gluteus medius muscle activity is both conflicting and limited. The primary aim was to investigate the relationship between foot type and gluteus medius muscle activity during shod walking. The secondary aims of this study were to explore the effect and amount of usage of a pair of unmodified prefabricated foot orthoses on gluteus medius muscle activity during shod walking.

Methods

Foot type was determined using the foot posture index and gluteus medius muscle activity was measured with surface electromyography in 50 healthy adults during shod walking. Participants were then fitted with prefabricated foot orthoses and required to return after 4 weeks. Pearson’s correlation and one-way ANOVA were used to determine effect of foot type. Paired t-tests and ANCOVA were used to determine effect of foot orthoses.

Results

Participants with a cavus foot type demonstrated significantly more gluteus medius mean (p = 0.04) and peak amplitude (p = 0.01), and a greater range in amplitude (p = 0.01) compared to participants with a neutral foot type. Compared to a planus foot type, participants with a cavus foot type demonstrated significantly larger mean (p = 0.02) and peak amplitude (p = 0.01), and a greater range in amplitude (p = 0.01). Prefabricated foot orthoses did not change the gluteus medius muscle activity.

Conclusion

When assessing healthy adults with a cavus foot type, clinicians and researchers should be aware that these participants may display higher levels of gluteus medius muscle activity during gait compared to neutral and planus type feet. Additionally, clinicians and researchers should be aware that the type of prefabricated foot orthoses used did not change gluteus medius muscle activity over 4 weeks. Future research should aim to explore this relationship between foot type and gluteus medius muscle activity in larger sample sizes, consider the potential role of other lower extremity muscles and biomechanical variables, and investigate if these findings also occur in people with pathology.

Immediate effects of using insoles with various wedges on activation and co-contraction indices of selected trunk muscles during load lifting

Trunk muscles play an important role during load lifting and contract to control trunk stability. The aim of present study was to investigate immediate effects of using various insole wedges on activation and co-contraction indices of selected trunk muscles during load lifting. Thirty able-bodied males completed load lifting task using nine various insole wedges. The results showed these significant differences: for normalized mean amplitude of RA muscle between posterior and anterior-medial wedges and for QL muscle between posterior and lateral wedges, for normalized peak amplitude of RA muscle between posterior and anterior-medial wedges, for median frequency of LES muscle between anterior-medial and anterior-lateral wedges, and for co-contraction of RA/TES, RA/LES and RA/MU between posterior and anterior-medial wedges (P = 0.001). These findings should be considered during designation of shoe or insole for work environments. Future studies need to assess other biomechanical aspects of using various insole wedges during work-related tasks.

Foot hyperpronation alters lumbopelvic muscle function during the stance phase of gait

BACKGROUND

Although altered muscular control of the lumbopelvic region is one of the main risk factors for the development of low back pain and dysfunction, the influence of abnormal foot posture on lumbopelvic muscular function has not been investigated.

RESEARCH QUESTION

To determine possible functional changes due to hyperpronation in the main muscles that control the lumbopelvic segment.

METHODS

Kinematic and kinetic data were collected from 15 persons with hyperpronated feet and compared to a control group of 15 persons with normally aligned feet during the stance phase of gait. A generic OpenSim musculoskeletal model was scaled for each participant. A computed muscle control approach was used to produce a forward dynamic simulation of walking to determine muscle function.

RESULTS

In the hyperpronation group significantly greater peak forces were observed in the erector spinae, iliopsoas and abdominals compared to controls. The former group showed peak latencies for abdominal muscles during early stance, and for erector spinae muscles during both early and late stance. No significant between-group differences were found in gluteus maximus muscle activation in the stance phase of gait.

SIGNIFICANCE

Abnormal foot pronation can change the timing and intensity of lumbopelvic muscle activation. These changes may predispose people to develop secondary dysfunctions.

Ground reaction forces and muscle activity while walking on sand versus stable ground in individuals with pronated feet compared with healthy controls

BACKGROUND

Sand is an easy-to-access, cost-free resource that can be used to treat pronated feet (PF). Therefore, the aims of this study were to contrast the effects of walking on stable ground versus walking on sand on ground reaction forces (GRFs) and electromyographic (EMG) activity of selected lower limb muscles in PF individuals compared with healthy controls.

METHODS

Twenty-nine controls aged 22.2±2.5 years and 30 PF individuals aged 22.2±1.9 years were enrolled in this study. Participants walked at preferred speed and in randomized order over level ground and sand. A force plate was included in the walkway to collect GRFs. Muscle activities were recorded using EMG system.

RESULTS

No statistically significant between-group differences were found in preferred walking speed when walking on stable ground (PF: 1.33±0.12 m/s; controls: 1.35±0.14 m/s; p = 0.575; d = 0.15) and sand (PF: 1.19±0.11 m/s; controls: 1.23±0.18 m/s; p = 0.416; d = 0.27). Irrespective of the group, walking on sand (1.21±0.15 m/s) resulted in significantly lower gait speed compared with stable ground walking (1.34±0.13 m/s) (p<0.001; d = 0.93). Significant main effects of "surface" were found for peak posterior GRFs at heel contact, time to peak for peak lateral GRFs at heel contact, and peak anterior GRFs during push-off (p<0.044; d = 0.27-0.94). Pair-wise comparisons revealed significantly smaller peak posterior GRFs at heel contact (p = 0.005; d = 1.17), smaller peak anterior GRFs during push-off (p = 0.001; d = 1.14), and time to peak for peak lateral GRFs (p = 0.044; d = 0.28) when walking on sand. No significant main effects of "group" were observed for peak GRFs and their time to peak (p>0.05; d = 0.06-1.60). We could not find any significant group by surface interactions for peak GRFs and their time to peak. Significant main effects of "surface" were detected for anterior-posterior impulse and peak positive free moment amplitude (p<0.048; d = 0.54-0.71). Pair-wise comparisons revealed a significantly larger peak positive free moment amplitude (p = 0.010; d = 0.71) and a lower anterior-posterior impulse (p = 0.048; d = 0.38) when walking on sand. We observed significant main effects of "group" for the variable loading rate (p<0.030; d = 0.59). Pair-wise comparisons revealed significantly lower loading rates in PF compared with controls (p = 0.030; d = 0.61). Significant group by surface interactions were observed for the parameter peak positive free moment amplitude (p<0.030; d = 0.59). PF individuals exhibited a significantly lower peak positive free moment amplitude (p = 0.030, d = 0.41) when walking on sand. With regards to EMG, no significant main effects of "surface", main effects of "group", and group by surface interactions were observed for the recorded muscles during the loading and push-off phases (p>0.05; d = 0.00-0.53).

CONCLUSIONS

The observed lower velocities during walking on sand compared with stable ground were accompanied by lower peak positive free moments during the push-off phase and loading rates during the loading phase. Our findings of similar lower limb muscle activities during walking on sand compared with stable ground in PF together with lower free moment amplitudes, vertical loading rates, and lower walking velocities on sand may indicate more relative muscle activity on sand compared with stable ground. This needs to be verified in future studies.

Effects of heel lifts on lower limb biomechanics and muscle function: A systematic review

BACKGROUND

Heel lifts, placed inside footwear are recommended for the management of numerous musculoskeletal conditions. Despite the potential therapeutic benefit of heel lifts, the mechanism(s) by which they exert their effects is unclear. The aim of this systematic review was to synthesise reported findings and summarise the effects of heel lifts on lower limb biomechanics and muscle function.

RESEARCH QUESTION

Do heel lifts affect lower limb biomechanics and muscle function during walking and running?

METHODS

Electronic databases (MEDLINE, EMBASE, CINAHL, SPORTDiscus, AMED) were searched from inception to April 2018. Studies were included if they (i) included participants without a limb length discrepancy or neurological condition, (ii) evaluated the effect of bilateral heel lifts that were removable (attached to the participants' foot (barefoot) or inserted inside footwear) or an existing feature of a shoe, and (iii) assessed lower limb biomechanics or muscle function during walking or running in asymptomatic or symptomatic participants.

RESULTS

A total of 23 studies (377 participants) were included. Study quality, assessed using a Modified Quality Index, ranged from 5 to 13 out of 15. A large number of biomechanical parameters were assessed, but few effects were statistically significant. The differences that were significant and had a large effect size are described below. In asymptomatic participants, heel lifts of 10 mm decreased duration of swing phase (standardised mean difference [SMD] = -1.3) and heel lifts of at least 5 cm decreased velocity (SMD = -0.93) during walking. In asymptomatic participants, heel lifts of 15 mm decreased maximum ankle dorsiflexion angle (SMD = -1.5) and heel lifts of 12 and 18 mm decreased gastrocnemius muscle tendon unit length (SMD = -0.96) during running. In participants with restricted ankle joint dorsiflexion, heel lifts of 6 and 9 mm increased medial gastrocnemius electromyography amplitude (SMD between 0.68 and 0.98) during walking. In participants with haemophilia, heel lifts of 9 mm increased ankle joint maximum range of motion (SMD = 1.6) during walking.

SIGNIFICANCE

Heel lifts affect specific lower limb biomechanical and muscle function parameters during walking and running. The clinical relevance and potential therapeutic benefits of these effects needs further investigation.

Prefabricated foot orthoses compared to a placebo intervention for the treatment of chronic nonspecific low back pain: a study protocol for a randomised controlled trial

BACKGROUND

Prefabricated foot orthoses are used to treat chronic nonspecific low back pain, however their effectiveness and potential mechanism of action is unclear. The primary aims of the study are to investigate the effectiveness of prefabricated foot orthotic devices for reducing pain and improving function in people with chronic nonspecific low back pain over 52 weeks.

METHODS

This study is a participant and assessor blinded, parallel-group, superiority randomised (1:1) controlled trial. The study will recruit 60 participants aged 18 to 65 years with chronic nonspecific low back pain. Participants will undergo randomisation to a control group (The Back Book) or an intervention group (prefabricated foot orthoses and The Back Book). The primary outcome measures will be change in pain and function from baseline to 12 (primary time point), 26, and 52 weeks. Secondary outcome measures include: gluteus medius muscle activity and transversus abdominis muscle thickness from baseline to 12 weeks, physical activity over 12, 26, and 52 weeks, and correlation between foot type and change in measures of pain and function. Number of hours per day and week that the prefabricated orthoses are worn, as well as, adverse events will be self-reported by participants. Data will be analysed using the intention-to-treat principle.

DISCUSSION

This trial will primarily evaluate the effectiveness of prefabricated foot orthotic devices for reducing pain and improving function in people with chronic nonspecific low back pain over 52 weeks. It is expected that this study will provide clinicians and researchers with an understanding of the role that prefabricated foot orthoses may have in the treatment of chronic nonspecific low back pain and a potential mechanism of action, and whether foot type influences the outcome.

TRIAL REGISTRATION

ACTRN12618001298202.

The influence of foot hyperpronation on pelvic biomechanics during stance phase of the gait: A biomechanical simulation study

Despite the theoretical link between foot hyperpronation and biomechanical dysfunction of the pelvis, the literature lacks evidence that confirms this assumption in truly hyperpronated feet subjects during gait. Changes in the kinematic pattern of the pelvic segment were assessed in 15 persons with hyperpronated feet and compared to a control group of 15 persons with normally aligned feet during the stance phase of gait based on biomechanical musculoskeletal simulation. Kinematic and kinetic data were collected while participants walked at a comfortable self-selected speed. A generic OpenSim musculoskeletal model with 23 degrees of freedom and 92 muscles was scaled for each participant. OpenSim inverse kinematic analysis was applied to calculate segment angles in the sagittal, frontal and horizontal planes. Principal component analysis was employed as a data reduction technique, as well as a computational tool to obtain principal component scores. Independent-sample t-test was used to detect group differences. The difference between groups in scores for the first principal component in the sagittal plane was statistically significant (p = 0.01; effect size = 1.06), but differences between principal component scores in the frontal and horizontal planes were not significant. The hyperpronation group had greater anterior pelvic tilt during 20%–80% of the stance phase. In conclusion, in persons with hyperpronation we studied the role of the pelvic segment was mainly to maintain postural balance in the sagittal plane by increasing anterior pelvic inclination. Since anterior pelvic tilt may be associated with low back symptoms, the evaluation of foot posture should be considered in assessing the patients with low back and pelvic dysfunction.

Low back pain and disability in individuals with plantar heel pain

BACKGROUND

Lack of response to plantar heel pain (PHP) treatment may be related to unmanaged low back pain (LBP) and low back dysfunction, but a relationship between LBP and PHP has not been established. The purpose of this investigation was to compare the prevalence of LBP among individuals with and without PHP and to assess the association between low back disability and foot/ankle function.

METHODS

A cross-sectional study compared the prevalence and likelihood of LBP in individuals with (n=27) and without (n=27) PHP matched to age, sex, BMI, foot posture, and foot mobility. In individuals with PHP, correlations were examined between foot/ankle function using the foot and ankle ability measure (FAAM), low back disability using the Oswestry low back disability questionnaire (OSW), duration of PHP symptoms, body mass index (BMI), and age.

RESULTS

A greater percentage of individuals with PHP had LBP (74% versus 37% of controls, odds ratio=5.2, P=0.009) and higher levels of low back disability (17% higher OSW score than controls, P<0.001). In individuals with PHP, FAAM scores were correlated with OSW scores (ρ=-0.463, P=0.015), but not with duration of PHP symptoms, BMI, or age (P>0.150).

CONCLUSIONS

Individuals with PHP had a greater prevalence of LBP and higher low back disability that was correlated to reduced foot and ankle function. Treatment to address both local and proximal impairments, including impairments related to LBP, may be warranted to improve the management of PHP.

Footwear-Generated Dynamic Biomechanical Manipulation and Perturbation Training for Chronic Nonspecific Low Back Pain

BACKGROUND

Home-based therapy optimizing biomechanics and neuromuscular control is increasingly recognized as a treatment option for chronic nonspecific low back pain (CNSLBP). However, its impact on pain, function, and gait is limited among patients in a metropolitan area.

OBJECTIVE

To evaluate the change of pain, function, and gait parameters with home-based therapy with the use of footwear-generated biomechanical manipulation and perturbation training in a population with CNSLBP in a metropolitan area.

DESIGN

Prospective observational study.

SETTING

Outpatient rehabilitation clinic at an academic teaching hospital.

PARTICIPANTS

One hundred sixteen patients with CNSLBP for more than 6 months.

INTERVENTION

Six months of home-based therapy with a biomechanical device using 4 modular elements attached to a foot-worn platform.

MAIN OUTCOME MEASURES

Instrumental gait analysis (gait velocity, step length, single limb support phase % of gait cycle), Numeric Rating Scale for pain, and Oswestry Disability Questionnaire Index for pain and function.

RESULTS

Only 43 patients (37.1%) completed the study. Among 43 patients, mean gait velocity increased from 86.6 ± 20.7 to 99.7 ± 22.1 cm/s (P < .0001) in 6 months. Mean left step length increased from 51.1 ± 8.4 to 54.8 ± 9.8 cm (P < .0001). Mean right step length increased from 51.0 ± 7.9 to 55.4 ± 9.0 cm (P < .0001). Mean single limb support increased from 36.4 ± 2.8 to 37.2 ± 2.5%, (P = .208) in the right side and from 36.6 ± 3.0 to 37.8 ± 4.4%, (P = .019) in the left side. Median Oswestry Disability Questionnaire Index score improved from 28 (18-44; interquartile range) to 17 (10-35) (P = .045). Mean Numeric Rating Scale for back pain improved from 7.7 ± 1.8 to 3.3 ± 3.1 (P < .0001).

CONCLUSION

At 6 months, patients with CNSLBP undergoing home-based therapy with footwear-generated biomechanical manipulation and perturbation training demonstrated significant improvement of objective gait parameters, pain, and function.

LEVEL OF EVIDENCE

IV.

Muscle activity and kinetics of lower limbs during walking in pronated feet individuals with and without low back pain

The objectives of this study were to investigate whether excessive feet pronation alters the joints' kinematics, kinetics and the activity of involved muscles during gait in low back pain patients.

METHODS

The lower limb joints' motion, moment and power, as well as the activity of involved muscles during walking were measured in a control group, and two experimental groups including a group with excessive feet pronation only, and another group of low back pain patients with excessive feet pronation.

RESULTS

In both experimental groups, ankle inversion, knee flexion and internal rotation, hip internal rotation, plantar flexors' moment, hip flexors' moment, and peak positive ankle power were lower than those in control group (p < .05). Besides, in patients, higher activity of gastrocnemius medialis, gluteus medius, erector spinae, and internal oblique muscles, and lower negative power at the ankle and peak positive power at the knee were observed (p < .05). In conclusion, pronated feet with low back pain was associated with less ankle inversion and knee flexion, higher knee and hip internal rotation, higher muscle activity, less energy absorption at the ankle, and reduced positive power at the knee. This study reveals that strengthening of the muscles especially knee extensors are of great importance in low back pain patients with feet pronation.

Acute Isolated Tear of Gluteus Medius in Young Male

The hip rotator cuff tear usually develops in the middle-aged through gradual degenerative changes, similar to rotator cuff tears in the shoulder. An acute tear in the hip abductor by a traumatic event in young ages is very uncommon. The authors experienced an unusual case of an acute traumatic tear isolated to the gluteus medius in a young male; thus, we report the treatment results in this rare case with a review of the literature.

Differences in lower limb muscle activation patterns during Sit to Stand Task for different heel heights

The purpose of this study was to investigate differences in lower limb muscle activation patterns for females wearing shoes with different heel heights during Sit to Stand Task (STS). Ten female participants with no prior history of neurological disorders participated in this study. Surface electromyography (sEMG) characteristics were recorded for four different heel heights (ranging from 4cm to 10cm) while performing the STS task. Signal processing analysis suggests that muscle activities increases on elevated heel heights, which may induce muscle imbalance for frequent STS tasks. In addition, results of muscle utilisation (percentage) for different heel heights suggest that lower limb muscles tend to compensate in order to maintain postural balance.

The effect of foot orthoses on joint moment asymmetry in male children with flexible flat feet

INTRODUCTION

It has been widely postulated that structural and functional misalignments of the foot, such as flat foot, may cause mechanical deviations of the lower limb during walking. The aim of this study was to investigate the effect of foot orthoses on lower extremity joint moment asymmetry during the stance phase of walking in children with asymptomatic flexible flat feet.

METHODS

Fourteen volunteer male children, clinically diagnosed with flexible flat feet, participated in this study. Subjects completed 12 walking trials at a self-selected walking speed while 3-dimensional kinematic and kinetic data were collected for two conditions: shod with no orthoses, and shod with orthoses. The gait asymmetry index for each variable for each subject was defined as: (1-(lesser moment/greater moment)) × 100.

RESULTS

Results reveal no significant differences in ankle or knee joint moment asymmetry. However, the use of foot orthoses decreased asymmetry for the hip abduction moment (P = 0.04) compared to walking without orthoses and also resulted in subtle, non-significant increases in frontal plane subtalar and sagittal plane knee and hip joints moment asymmetry.

CONCLUSION

We conclude that foot orthoses decrease frontal plane hip joint moment asymmetry, but have little effect on ankle and knee joint asymmetry.

The effects of biomechanical foot orthoses on the gait patterns of patients with malalignment syndrome as determined by three dimensional gait analysis

[Purpose] The biomechanical effects of foot orthoses on malalignment syndrome have not been fully clarified. This experimental investigation was conducted to evaluate the effects of orthoses on the gait patterns of patients with malalignment syndrome. [Subjects and Methods] Ten patients with malalignment syndrome were recruited. For each participant, kinematic and kinetic data were collected under three test conditions: walking barefoot, walking with flat insoles in shoes, and walking with a biomechanical foot orthosis (BFO) in shoes. Gait patterns were analyzed using a motion analysis system. [Results] Spatiotemporal data showed the step and stride lengths when wearing shoes with flat insoles or BFO were significantly greater than when barefoot, and that the walking speed when wearing shoes with BFO was significantly faster than when walking barefoot or with shoes with flat insoles. Kinetic data, showed peak pelvic tilt and obliquity angle were significantly greater when wearing BFO in shoes than when barefoot, and that peak hip flexion/extension angle and peak knee flexion/extension and rotation angles were significantly greater when wearing BFO and flat insoles in shoes than when barefoot. [Conclusion] BFOs can correct pelvic asymmetry while walking.

Gait ground reaction force characteristics of low back pain patients with pronated foot and able-bodied individuals with and without foot pronation

The link between gait parameters and foot abnormalities in association with low back pain is not well understood. The objective of this study was to investigate the effects of excessive foot pronation as well as the association of LBP with excessive foot pronation on the GRF components during shod walking.

METHODS

Forty-five subjects were equally divided into a control group, a group of subjects with pronated feet only, and another group with pronated feet and LBP. Ground reaction forces were analyzed during shod walking.

RESULTS

Foot pronation without low back pain was associated with increased lateral-medial ground reaction force, impulse, and time to peak of all reaction forces in heel contact phase (p<0.03). In low back pain patients with pronated foot, greater vertical reaction forces (p=0.001) and loading rate, and time to peak on propulsion force were observed compared to pronated foot without low back pain group. Impulse in posterior-anterior reaction force was smaller in the able-bodied group with normal foot than in the other groups (p<0.05). Positive peak of free moments of the LBP group was significantly greater than that in other groups (p<0.05). In conclusion, foot pronation alone was not associated with elevated vertical ground reaction forces. While, low back pain patients with foot pronation displayed higher vertical ground reaction force as well as higher loading rate. Present results reveal that gait ground reaction force components in low back pain patients with pronated foot may have clinical values on the prognosis and rehabilitation of mechanical LBP patients.

Are flexible flat feet associated with proximal joint problems in children?

The role of flexible flat feet (FF) in the development of musculoskeletal symptoms at joints proximal to the ankle is unclear. We undertook an observational study to investigate the relationship between foot posture and the proximal joints in children. It was hypothesised that reduced arch height would be associated with proximal joint symptoms and altered gait kinematics and kinetics particularly in the transverse plane at the hip and knee. Ninety-five children between the ages of 8-15 were recruited into this ethically approved study. Foot posture was classified using the arch height index (AHI). The frequency of knee and hip/back pain was documented, and each child underwent three dimensional gait analysis. Reduced arch height was associated with increased odds of knee symptoms (p<0.01) and hip/back symptoms (p=0.01). A flat foot posture was also significantly associated with a reduction in the second peak of the vertical ground reaction force (p=0.03), which concomitantly affected late stance hip and knee moments. A reduced AHI was also associated with increased pelvic retraction and increased knee valgus in midstance. No kinematic and kinetic parameter associated with a flat foot posture related to increased proximal joint symptoms in the FF group. Children with a flatter foot posture are more likely to have pain or discomfort at the knee, hip and back; however, the mechanisms by which this occurs remain unclear. Treating FF without explicit understanding of how it relates to symptoms is difficult, and further work in this area is required.

The effect of gait training with shoe inserts on the improvement of pain and gait in sacroiliac joint patients

[Purpose] The purpose of the current research was to identify how gait training with shoe inserts affects the pain and gait of sacroiliac joint dysfunction patients. [Subjects and Methods] Thirty subjects were randomly selected and assigned to be either the experimental group (gait training with shoe insert group) or control group. Each group consisted of 15 patients. Pain was measured by Visual Analogue Scale, and foot pressure in a standing position and during gait was measured with a Gateview AFA-50 system (Alpus, Seoul, Republic of Korea). A paired sample t-test was used to compare the pain and gait of the sacroiliac joint before and after the intervention. Correlation between pain and walking after gait training with shoe inserts was examined by Pearson test. The level of significance was set at α=0.05. [Results] It was found that application of the intervention to the experimental group resulted in a significant decrease in sacroiliac joint pain. It was also found that there was a significant correlation between Visual Analogue Scale score and dynamic asymmetric index (r= 0.796) and that there was a negative correlation between Visual Analogue Scale score and forefoot/rear foot peak pressure ratio (r=-0.728). [Conclusion] The results of our analysis lead us to conclude that the intervention with shoe inserts had a significant influence on the pain and gait of sacroiliac joint patients.

Muscle-Activation Onset Times With Shoes and Foot Orthoses in Participants With Chronic Ankle Instability

CONTEXT

Participants with chronic ankle instability (CAI) use an altered neuromuscular strategy to shift weight from double-legged to single-legged stance. Shoes and foot orthoses may influence these muscle-activation patterns.

OBJECTIVE

To evaluate the influence of shoes and foot orthoses on onset times of lower extremity muscle activity in participants with CAI during the transition from double-legged to single-legged stance.

DESIGN

Cross-sectional study.

SETTING

Musculoskeletal laboratory.

PATIENTS OR OTHER PARTICIPANTS

A total of 15 people (9 men, 6 women; age = 21.8 ± 3.0 years, height = 177.7 ± 9.6 cm, mass = 72.0 ± 14.6 kg) who had CAI and wore foot orthoses were recruited.

INTERVENTION(S)

A transition task from double-legged to single-legged stance was performed with eyes open and with eyes closed. Both limbs were tested in 4 experimental conditions: (1) barefoot (BF), (2) shoes only, (3) shoes with standard foot orthoses, and (4) shoes with custom foot orthoses (SCFO).

MAIN OUTCOME MEASURE(S)

The onset of activity of 9 lower extremity muscles was recorded using surface electromyography and a single force plate.

RESULTS

Based on a full-factorial (condition, region, limb, vision) linear model for repeated measures, we found a condition effect (F(3,91.8) = 9.39, P < .001). Differences among experimental conditions did not depend on limb or vision condition. Based on a 2-way (condition, muscle) linear model within each region (ankle, knee, hip), earlier muscle-activation onset times were observed in the SCFO than in the BF condition for the peroneus longus (P < .001), tibialis anterior (P = .003), vastus medialis obliquus (P = .04), and vastus lateralis (P = .005). Furthermore, the peroneus longus was activated earlier in the shoes-only (P = .02) and shoes-with-standard-foot-orthoses (P = .03) conditions than in the BF condition. No differences were observed for the hip muscles.

CONCLUSIONS

Earlier onset of muscle activity was most apparent in the SCFO condition for ankle and knee muscles but not for hip muscles during the transition from double-legged to single-legged stance. These findings might help clinicians understand how shoes and foot orthoses can influence neuromuscular control in participants with CAI.

Associations of foot posture and function to lower extremity pain: results from a population-based foot study

OBJECTIVE

Studies have implicated foot posture and foot function as risk factors for lower extremity pain. Empirical population-based evidence for this assertion is lacking; therefore, the purpose of this study was to evaluate cross-sectional associations of foot posture and foot function to lower extremity joint pain in a population-based study of adults.

METHODS

Participants were members of the Framingham Foot Study. Lower extremity joint pain was determined by the response to the National Health and Nutrition Examination Survey-type question, "On most days do you have pain, aching or stiffness in your (hips, knees, ankles, or feet)?" The Modified Arch Index classified participants as having planus, rectus (referent), or cavus foot posture. The Center of Pressure Excursion Index classified participants as having overpronated, normal (referent), or oversupinated foot function. Crude and adjusted (age, sex, and body mass index) logistic regression determined associations of foot posture and function to lower extremity pain.

RESULTS

Participants with planus structure had higher odds of knee (odds ratio [OR] 1.57, 95% confidence interval [95% CI] 1.24-1.99) or ankle (OR 1.47, 95% CI 1.05-2.06) pain, whereas those with a cavus foot structure had increased odds of ankle pain only (OR 7.56, 95% CI 1.99-28.8) and pain at 1 lower extremity site (OR 1.37, 95% CI 1.04-1.80). Associations between foot function and lower extremity joint pain were not statistically significant except for a reduced risk of hip pain in those with an oversupinated foot function (OR 0.69, 95% CI 0.51-0.93).

CONCLUSION

These findings offer a link between foot posture and lower extremity pain, highlighting the need for longitudinal or intervention studies.

Foot posture, leg length discrepancy and low back pain--their relationship and clinical management using foot orthoses--an overview

Mechanical low back pain (LBP) is a very common, expensive, and significant health issue in the western world. Functional musculoskeletal conditions are widely thought to cause mechanical low back pain. The role of foot posture and leg length discrepancy in contributing to abnormal biomechanics of the lumbopelvic region and low back pain is not sufficiently investigated. This critical review examines the evidence for the association between foot function, particularly pronation, and mechanical LBP. It also explores the evidence for a role for foot orthoses in the treatment of this condition. There is a body of evidence to support the notion that foot posture, particularly hyperpronation, is associated with mechanical low back pain. Mechanisms that have been put forward to account for this finding are based on either mechanical postural changes or alterations in muscular activity in the lumbar and pelvic muscles. More research is needed to explore and quantify the effects of foot orthoses on chronic low back pain, especially their effects on lumbopelvic muscle function and posture. The clinical implications of this work are significant since foot orthoses represent a simple and potentially effective therapeutic measure for a clinical condition of high personal and social burden.

The effects of high heeled shoes on female gait: a review

Walking is the most common form of human locomotion. From a motor control perspective, human bipedalism makes the task of walking extremely complex. For parts of the step cycle, there is only one foot on the ground, so both balance and propulsion are required in order for the movement to proceed smoothly. One condition known to compound the difficulty of walking is the use of high heeled shoes, which alter the natural position of the foot-ankle complex, and thereby produce a chain reaction of (mostly negative) effects that travels up the lower limb at least as far as the spine. This review summarises recent studies that have examined acute and chronic effects of high heels on balance and locomotion in young, otherwise healthy women. Controversial issues, common study limitations and directions for future research are also addressed in detail.

Foot posture, foot function and low back pain: the Framingham Foot Study

OBJECTIVE

Abnormal foot posture and function have been proposed as possible risk factors for low back pain, but this has not been examined in detail. The objective of this study was to explore the associations of foot posture and foot function with low back pain in 1930 members of the Framingham Study (2002-05).

METHODS

Low back pain, aching or stiffness on most days was documented on a body chart. Foot posture was categorized as normal, planus or cavus using static weight-bearing measurements of the arch index. Foot function was categorized as normal, pronated or supinated using the centre of pressure excursion index derived from dynamic foot pressure measurements. Sex-specific multivariate logistic regression models were used to examine the associations of foot posture, foot function and asymmetry with low back pain, adjusting for confounding variables.

RESULTS

Foot posture showed no association with low back pain. However, pronated foot function was associated with low back pain in women [odds ratio (OR) = 1.51, 95% CI 1.1, 2.07, P = 0.011] and this remained significant after adjusting for age, weight, smoking and depressive symptoms (OR = 1.48, 95% CI 1.07, 2.05, P = 0.018).

CONCLUSION

These findings suggest that pronated foot function may contribute to low back symptoms in women. Interventions that modify foot function, such as orthoses, may therefore have a role in the prevention and treatment of low back pain.

Effects of customized foot orthotics on reported disability and analgesic use in patients with chronic low back pain associated with motor vehicle collisions

OBJECTIVE

The purpose of this study was to compare reported disability due to chronic low back pain following a motor vehicle collision between groups of those using customized foot orthotics and those not using orthotics.

METHODS

Sixty-six consecutive patients referred from primary care medical physicians for the complaint of chronic (> 3 months) low back pain following a motor vehicle collision were included. Thirty patients received "usual care" that included prescription of an exercise therapy program in addition to analgesics. Thirty-four patients received the same therapy along with customized foot orthotics. All patients completed the Oswestry Disability Index at the initiation of the study and at 8-week follow-up. The number of participants using any type of prescription analgesic for their back pain at baseline and at 8 weeks was also recorded.

RESULTS

All patients completed treatment, and the baseline and 8-week questionnaires. Both treatment groups were well matched in terms of age, sex distribution, and duration of low back pain, as well as baseline Oswestry Disability Index score. At 8 weeks, although both groups had improved, the group that used orthotics had a lower Oswestry Disability Index than the usual care group (P < .05), with a smaller proportion of the orthotics group using any form of prescribed analgesics for back pain (P < .05).

CONCLUSIONS

In this study, patients with chronic low back pain following a motor vehicle collision who used orthotics in addition to usual care had improved short-term outcomes compared with usual care alone.

Foot orthoses for the management of low back pain: a qualitative approach capturing the patient's perspective

BACKGROUND

The onset of non specific low back pain is associated with heavy lifting, age, female gender, and poor general health, with psychological factors being predictors of it becoming chronic. Additionally, it is thought that altered lower limb biomechanics are a contributory factor, with foot orthoses increasingly being considered as an appropriate intervention by physiotherapists and podiatrists. However, research into the effect of foot orthoses is inconclusive, primarily focusing on the biomechanical effect and not the symptomatic relief from the patient's perspective. The aim of this study was to explore the breadth of patients' experiences of being provided with foot orthoses and to evaluate any changes in their back pain following this experience.

METHOD

Following ethical approval, participants (n = 25) with non-specific low back pain associated with altered lower limb biomechanics were provided with customised foot orthoses. At 16 weeks after being provided with the foot orthoses, conversational style interviews were carried out with each patient. An interpretivistic phenomenological approach was adopted for the data collection and analysis.

RESULTS

For these participants, foot orthoses appeared to be effective. However, the main influence on this outcome was the consultation process and a patient focussed approach. The consultation was an opportunity for fostering mutual understanding, with verbal and visual explanation reassuring the patient and this influenced the patient's beliefs, their engagement with the foot orthoses (physical) and their experience of low back pain (psychological).

CONCLUSION

Clinicians need to adopt 'psychologically informed practice' in relation to the provision of foot orthoses. Likewise, researchers should consider all the influencing factors found in this study, both in relation to their study protocol and the outcomes they plan to measure.

The influence of high and low heeled shoes on EMG timing characteristics of the lumbar and hip extensor complex during trunk forward flexion and return task

BACKGROUND

Recent studies suggest that wearing high-heel shoes increases the risk of developing certain musculoskeletal pain conditions. In this study we sought to examine whether heel height alters lumbar and hip extensor muscle timing characteristics during a standardized trunk flexion task.

METHODS

Thirty-one young, healthy women (22-27 years; 168.6 ± 5.1 cm; 57.1 ± 11.8 kg) participated in this study. Lumbar erector spinae (ES), gluteus maximus (GM), and biceps femoris (BF) electromyographic (EMG) signals were recorded during a trunk flexion task where subjects were instructed to flex their trunk in the sagittal plane and then return to a neutral posture. The task was repeated under three footwear conditions: while wearing no footwear, while wearing shoes with 4-cm heels, and while wearing shoes with 10-cm heels. EMG onset and offset times, as well as EMG duration, were calculated for each muscle and compared across conditions.

RESULTS

We observed a significantly earlier onset of the ES EMG activity (1.36 ± 0.61 vs. 1.56 ± 0.67 s), and significantly delayed onset of the GM EMG activity (1.72 ± 0.66 vs. 1.28 ± 0.58 s) during the flexion phase of movement in the 10-cm heeled compared to the no footwear condition. The GM muscle also exhibited an earlier offset time in the 10-cm heel condition compared to the no footwear condition during the flexion movement (2.57 ± 0.67 vs. 3.30 ± 0.61 s) as well as during the return from flexion movement phase (10.87 ± 0.58 vs. 11.69 ± 0.65 s). These alterations in timing characteristic resulted in an overall decrease in the EMG duration for the GM muscle during the flexion movement.

CONCLUSION

The results of this study suggest that high-heels alter trunk and hip extensor muscle coordination patterns. These findings, when considered in combination with other recent findings on the biomechanical effects of wearing high-heels, raise concern about whether wearing high heels results in abnormal spine loading patterns and increases the risk for developing musculoskeletal injuries.

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.

A cohort-controlled trial of the addition of customized foot orthotics to standard care in fibromyalgia

Customized foot orthotics are widely prescribed for patients with chronic, non-specific low back pain and lower limb pain, but there are few trials demonstrating effectiveness, and none for fibromyalgia. A total of 67 consecutive patients presenting with chronic, widespread pain, who met the 1990 American College of Rheumatology criteria for fibromyalgia, were included in the study. A total of 32 subjects were prescribed a spinal exercise therapy program along with analgesics. These subjects formed the Control group. A second group, comprised of 35 subjects, received the same therapy, along with customized foot orthotics (Orthotics group). All subjects completed the Revised Fibromyalgia Impact Questionnaire (FIQR) at the initiation of the study and at 8 weeks follow-up. The number of subjects using any type of prescription analgesic or other medication for chronic pain at baseline and at 8 weeks was also recorded. A total of 30 subjects in the Control group and 33 in the Orthotics group completed the study. All subjects completed the baseline and 8-week FIQR. The two groups were well matched in terms of age (45.3 ± 11.5 years in the Orthotics group vs. 47.2 ± 8.7 years in the cohort Control), medication use, duration of pain (6.5 ± 4.3 years in the Orthotics group vs. 6.2 ± 3.4 years in the cohort Control group), as well as baseline FIQR scores (55.2 ± 11.0 in the Orthotics group vs. 56.3 ± 12.2 in the cohort Control group). At 8 weeks, the Orthotics group had a greater reduction in the FIQR score than the cohort Control group (reduction of 9.9 ± 5.9 vs. 4.3 ± 4.4, respectively), and this was mainly due to changes in the 'function' domain of the FIQR (reduction of 19.6 ± 9.4 in the Orthotics group vs. 8.1 ± 4.3 in the cohort Control group). As part of a complex intervention, in a cohort-controlled trial of primary care patients with fibromyalgia, the addition of custom-made foot orthotics to usual care appears to improve functioning in the short term.

Impact of soft and hard insole density on postural stability in older adults

A significant predictor of falls in the elderly population is attributed to postural instability. Thus, it is important to identify and implement practical clinical interventions to enhance postural stability in older adults. Shoe insoles have been identified as a mechanism to enhance postural control, and our study aimed to evaluate the impact of 2 shoe insoles on static standing balance in healthy, older adults compared with standing posture while barefoot. We hypothesized that both hard and soft shoe insoles would decrease postural sway compared with the barefoot condition. Indeed, excursion distances and sway areas were reduced, and sway velocity was decreased when wearing insoles. The hard insole was also effective when visual feedback was removed, suggesting that the more rigid an insole, the greater potential reduction in fall risk. Thus, shoe insoles may be a cost-effective, clinical intervention that is easy to implement to reduce the risk of falling in the elderly population.

Shoe orthotics for the treatment of chronic low back pain: a randomized controlled pilot study

OBJECTIVES

The purpose of this pilot study was to investigate the feasibility of a randomized clinical trial of shoe orthotics for chronic low back pain.

METHODS

The study recruited 50 patients with chronic low back pain through media advertising in a midwestern suburban area. Medical history and a low back examination were completed at a chiropractic clinic. Subjects were randomized to either a treatment group receiving custom-made shoe orthotics or a wait-list control group. After 6 weeks, the wait-list control group also received custom-made orthotics. This study measured change in perceived pain levels (Visual Analog Scale) and functional health status (Oswestry Disability Index) in patients with chronic low back pain at the end of 6 weeks of orthotic treatment compared with no treatment and at the end of 12 weeks of orthotic treatment.

RESULTS

This study showed changes in back pain and disability with the use of shoe orthotics for 6 weeks compared with a wait-list control group. It appears that improvement was maintained through the 12-week visit, but the subjects did not continue to improve during this time.

CONCLUSIONS

This pilot study showed that the measurement of shoe orthotics to reduce low back pain and discomfort after 6 weeks of use is feasible. A larger clinical trial is needed to verify these results.

EMG and kinematics analysis of the trunk and lower extremity during the sit-to-stand task while wearing shoes with different heel heights in healthy young women

This study investigated the EMG characteristics and the kinematics of the trunk and lower extremity during the sit-to-stand (STS) task while wearing 1-, 4-, and 8-cm high-heeled shoes. We examined differences in the EMG data of the internal oblique, erector spinae, medial hamstring, and rectus femoris muscles during the STS task. The motion of the hip joint during an STS task was measured with a NorAngle Electrogoniometer System. Twelve young healthy women were recruited to this study. EMG characteristics and the hip joint angle were recorded during the performance of an STS task by subjects wearing high-heeled shoes of three different heel heights. The muscle onset time and EMG activity during this task were analyzed. In 8-cm high-heeled shoes, the onset time for the erector spinae muscle was significantly delayed, and the onset latency for the medial hamstring and the rectus femoris was significantly decreased. There was increased activity in the erector spinae and rectus femoris muscle during this task when wearing 8-cm high-heeled shoes. The initial hip flexion angle at the start point of the STS task did not differ among the 1-, 4-, and 8-cm heel-height conditions, but the trunk flexion angle, corresponding to the displacement between the peak hip flexion and initial hip flexion, was significantly larger in the 8-cm heel-height condition than in the 1- and 4-cm heel-height conditions. The findings suggest that excessive heel height has the potential to induce muscle imbalance during the STS task.