The Influence of Plantar Short Foot Muscle Exercises on Foot Posture and Fundamental Movement Patterns in Long-Distance Runners, a Non-Randomized, Non-Blinded Clinical Trial

A four-week minimalist shoe walking intervention influences foot posture and balance in young adults-a randomized controlled trial

INTRODUCTION

Minimalist shoes (MS) are beneficial for foot health. The foot is a part of the posterior chain. It is suggested that interventions on the plantar foot sole also affect the upper segments of the body. This study aimed to investigate the local and remote effects along the posterior chain of four weeks of MS walking in recreationally active young adults.

METHODS

28 healthy participants (15 female, 13 male; 25.3 ± 5.3 years; 70.2 ± 11.9 kg; 175.0 ± 7.8 cm) were randomly assigned to a control- or intervention group. The intervention group undertook a four-week incremental MS walking program, which included 3,000 steps/day in the first week, increasing to 5,000 steps/day for the remaining three weeks. The control group walked in their preferred shoe (no MS). We assessed the following parameters in a laboratory at baseline [M1], after the four-week intervention [M2], and after a four-week wash-out period [M3]: Foot parameters (i.e., Foot Posture Index-6, Arch Rigidity Index), static single-leg stance balance, foot-, ankle-, and posterior chain range of motion, and muscle strength of the posterior chain. We fitted multiple hierarchically built mixed models to the data.

RESULTS

In the MS group, the Foot Posture Index (b = -3.72, t(51) = -6.05, p < .001, [-4.94, 2.51]) and balance (b = -17.96, t(49) = -2.56, p = .01, [-31.54, 4.37]) significantly improved from M1 to M2, but not all other parameters (all p >.05). The improvements remained at M3 (Foot Posture Index: b = -1.71, t(51) = -2.73, p = .009, [-4,94,0.48]; balance: b = -15.97, t(49) = -2.25, p = .03, [-29.72, 2.21]).

DISCUSSION

Walking in MS for four weeks might be advantageous for foot health of recreationally active young adults but no chronic remote effects should be expected.

Gait retraining targeting foot pronation: A systematic review and meta-analysis

Foot pronation is a prevalent condition known to contribute to a range of lower extremity injuries. Numerous interventions have been employed to address this issue, many of which are expensive and necessitate specific facilities. Gait retraining has been suggested as a promising intervention for modifying foot pronation, offering the advantage of being accessible and independent of additional materials or specific time. We aimed to systematically review the literature on the effect of gait retraining on foot pronation. We searched four databases including PubMed, Web of Science, Scopus and Embase from their inception through 20 June 2023. The Downs and Black appraisal scale was applied to assess quality of included studies. Two reviewers screened studies to identify studies reporting the effect of different methods of gait-retraining on foot pronation. Outcomes of interest were rearfoot eversion, foot pronation, and foot arch. Two authors separately extracted data from included studies. Data of interest were study design, intervention, variable, sample size and sex, tools, age, height, weight, body mass index, running experience, and weekly distance of running. Mean differences and 95% confidence intervals (CI) were calculated with random effects model in RevMan version 5.4. Fifteen studies with a total of 295 participants were included. The results of the meta-analysis showed that changing step width does not have a significant effect on peak rearfoot eversion. The results of the meta-analysis showed that changing step width does not have a significant effect on peak rearfoot eversion. Results of single studies indicated that reducing foot progression angle (MD 2.1, 95% CI 0.62, 3.58), lateralizing COP (MD -3.3, 95% CI -4.88, -1.72) can effectively reduce foot pronation. Overall, this study suggests that gait retraining may be a promising intervention for reducing foot pronation; Most of the included studies demonstrated significant improvements in foot pronation following gait retraining. Changing center of pressure, foot progression angle and forefoot strike training appeared to yield more favorable outcomes. However, further research is needed to fully understand its effectiveness and long-term benefits.

Intrinsic Foot Muscle Exercises With and Without Electric Stimulation

CONTEXT

Exercising intrinsic foot muscles (IFMs) can improve dynamic balance and foot posture. The exercises are not intuitive and electrotherapy (neuromuscular electrical stimulation [NMES]) has been suggested to help individuals execute the exercises. The aim of this study was to evaluate the effects of training IFM program on dynamic balance and foot posture and compare traditional training methods (TRAIN) with traditional training plus NMES on the perceived workload of the exercises, balance, and foot posture.

DESIGN

Randomized controlled trial.

METHODS

Thirty-nine participants were randomized to control, TRAIN, or NMES. TRAIN and NMES performed IFM exercises daily for 4 weeks; NMES received electrotherapy during the first 2 weeks of training. The Y-Balance test and arch height index were measured in all participants at baseline. The training groups were measured again at 2 weeks; all participants were measured at 4 weeks and 8 weeks, after 4 weeks of no training. Perceived workload (National Aeronautics and Space Administration Task Load Index) of exercises was assessed throughout the first 2 weeks and at 4 weeks.

RESULTS

A 4-week IFM training program demonstrated increases in Y-Balance (P = .01) for TRAIN and in arch height index (seated P = .03; standing P = .02) for NMES, relative to baseline. NMES demonstrated improvement in Y-Balance (P = .02) and arch height index standing (P = .01) at 2 weeks. There were no significant differences between the training groups. Groups were similar in the number responding to exercises in excess of minimal detectable change on all clinical measures. Perceived workload of the exercises decreased during the first 2 weeks of training (P = .02), and more notably at 4 weeks (P < .001). The groups did not differ in how they perceived the workload.

CONCLUSIONS

A 4-week IFM training program improved dynamic balance and foot posture. Adding NMES in early phases of training provided early improvement in dynamic balance and foot posture, but did not affect perceived workload.

Intrinsic muscles of the foot: Anatomy, function, rehabilitation

The intrinsic muscles of the foot are underappreciated structures in evaluating and treating lower extremity dysfunction. These muscles play a crucial role in the proper function of the foot during sport activities. The functions of these muscles are not generally well understood. Intrinsic dysfunction can lead to a variety of problems. Therefore, it is important for clinicians to have a good understanding of the anatomy and function of the intrinsic foot muscles in order to properly diagnose and treat foot injuries in patients. Published research on the rehabilitation of the intrinsic muscles provides insight into the function as well as benefits of treatment. The purpose of this review is to summarize the published research on the anatomy, function, contribution to pathology, as well as rehabilitation options for the intrinsic muscles of the foot.

Gluteus medius muscle strengthening exercise effects on medial longitudinal arch height in individuals with flexible flatfoot: a randomized controlled trial

This study aimed to compare the effects of 8 weeks of foot plus hip exercise to foot exercise alone on medial longitudinal arch (MLA) parameters; navicular drop (ND), arch height index (AHI), plantar pressure, static balance, and dynamic balance were measured at baseline, 4 weeks, and 8 weeks. A total of 52 healthy participants with bilateral flatfoot were randomly assigned into foot exercise (n=26) and foot plus hip exercise (n=26) group. At 4 weeks, the foot plus hip exercise group showed significantly less ND (P=0.002), plantar pressure at the medial forefoot (P=0.002), and mediolateral displacement (P=0.001) while showing a greater AHI (P=0.019) than the foot exercise group. At 8 weeks, there was also significantly less plantar pressure at the medial hindfoot (P=0.017) and less anteroposterior displacement (P=0.002) in the foot plus hip exercise group than in the foot exercise group. No significant differences between groups were found in dynamic balance. The addition of gluteus medius muscle strengthening exercise to foot exercise was more effective in supporting the MLA than performing foot exercise alone.

The effects of intrinsic foot muscles strengthening exercises on foot kinetic parameters in pronated foot subjects during forward jump landing

Background

Pronated foot is one of the most important factors that may lead to musculoskeletal injuries of the lower extremities. Among all treatments for this disorder, intrinsic foot muscles strengthening exercises (IFMSE) have an important role in management of the individuals with pronated foot. Although the effect of the IFMSE is well accepted in this population; however, their impacts on foot kinetic are yet to be clarified. The present study aims to identify the effects of the IFMSE on foot kinetic parameters in pronated foot individuals during forward jump landing.

Materials and Methods

In this quasi-experimental study, 20 asymptomatic male and female subjects (mean age of 22.65 ± 2.51 years) with pronated foot structures were selected by using a simple non-random sampling method. The ground reaction force (GRF), rate of loading (ROL), and the resultant vector of time to stabilization (RVTTS) were examined during a forward jump landing task by using a force plate before and after six weeks of the IFMSE.

Result

The findings showed that the following parameters were not significantly change before and after of the IFMSE: GRF (1.97 ± 0.49 vs. 2.03 ± 0.54, P =0.667), ROL (.09 ±0.12 vs. 08 ±.12, P =.632), and RVTTS (2836.60 ± 1144.62 vs. 2644.35 ± 704.71, P =.479).

Conclusion

In the pronated feet subjects, the IFMSE alone was not capable of changing the kinetic parameters of the foot, or the duration of using these exercises. In this study, six weeks may not be enough to make changes the foot kinetic parameters and therefore these exercises should be used for a longer period of time.

Contemporary Review: The Foot and Ankle in Long-Distance Running

Distance runners represent a unique patient population. The cyclic activity associated with distance running leads to a high incidence of injury. Gait patterns, the extrinsic and intrinsic muscles of the foot and ankle, foot strike pattern, shoe wear considerations, alignment, and orthotics are also all important considerations that must be considered by the treating provider. The purpose of this work is to review relevant functional anatomy, recent studies on gait patterns in running, orthotics, and theory on how the body moves through space during running in order to better equip the clinician to treat long distance runners.

Effects of 4 Weeks of High-Definition Transcranial Direct Stimulation and Foot Core Exercise on Foot Sensorimotor Function and Postural Control

Objective: This study aimed to examine the effects of 4 weeks of high-definition transcranial direct current stimulation (HD-tDCS) and foot core exercise (FCE) on foot sensorimotor function (i.e., toe flexor strength and passive ankle kinesthesia) and postural control.

Methods: In total, 36 participants were randomly assigned into three groups as follows: HD-tDCS, FCE, and the control group. A total of 12 training sessions were performed over 4 weeks (i.e., three sessions per week) in the laboratory. The HD-tDCS group received 20-min HD-tDCS with a current density of 2 mA, and the FCE group completed short foot exercise, towel curls, toe spread and squeeze, and balance board training. Participants in the control group just maintained the activities what they usually did and did not receive any interventions. Foot muscle strength, passive ankle kinesthesia, and postural control were assessed at baseline and post-intervention.

Results: HD-tDCS induced a greater decrease in the percentage changes in the passive kinesthesia thresholds of ankle inversion (p &lt; 0.001) and eversion (p = 0.013) than the control group. Compared with the control group, a significant increase in the percentage change in the metatarsophalangeal joint flexor strength was found in the HD-tDCS group (p = 0.008) and the FCE group (p = 0.027), and a significant increase in the percentage change in toe flexor strength was observed in the FCE group (p = 0.015). Moreover, FCE induced a greater reduction in the percent changes in the medial–lateral average center of gravity sway velocity in one-leg standing with eyes open (p = 0.033) and the anteroposterior average center of gravity sway velocity in one-leg standing with eyes closed (p &lt; 0.001) than control.

Conclusion: This study demonstrated that 4 weeks of HD-tDCS and FCE induced distinct benefits on foot sensorimotor function and the standing postural control performance in healthy young adults. HD-tDCS could improve the metatarsophalangeal joint flexor strength and the passive kinesthesia thresholds of ankle inversion and eversion. Meanwhile, FCE could also enhance foot muscle strength and enhance postural control performance in one-leg standing.

Effect of intrinsic foot muscles training on foot function and dynamic postural balance: A systematic review and meta-analysis

This systematic review aimed to analyse the effects of intrinsic foot muscle (IFM) training on foot function and dynamic postural balance. Keywords related to IFM training were used to search four databases (PubMed, CINAHL, SPORTDiscus and Web of Science databases.) for relevant studies published between January 2011 and February 2021. The methodological quality of the intervention studies was assessed independently by two reviewers by using the modified Downs and Black quality index. Publication bias was also assessed on the basis of funnel plots. This study was registered in PROSPERO (CRD42021232984). Sixteen studies met the inclusion criteria (10 with high quality and 6 with moderate quality). Numerous biomechanical variables were evaluated after IFM training intervention. These variables included IFM characteristics, medial longitudinal arch morphology and dynamic postural balance. This systematic review demonstrated that IFM training can exert positive biomechanical effects on the medial longitudinal arch, improve dynamic postural balance and act as an important training method for sports enthusiasts. Future studies should optimise standardised IFM training methods in accordance with the demands of different sports.

Classification of medial longitudinal arch kinematics during running and characteristics of foot muscle morphology in novice runners with pronated foot

BACKGROUND

Novice runners with pronated feet are at an increased risk of running-related injuries. However, not all runners with pronated feet have increased foot pronation during running. Moreover, although foot muscle morphology is related to static foot alignment, the relationship between foot muscle morphology and foot kinematics during running remains unclear. We aimed to determine foot kinematic patterns during running among novice runners with pronated feet and the presence of a relationship between these foot kinematic patterns and foot muscle morphology.

METHODS

Twenty-one novice runners with pronated feet participated in this study, and data on 39 lower limbs were collected. Data on foot kinematics during running (rearfoot strike) were collected using a three-dimensional motion capture system in terms of navicular height (NH) at initial contact and dynamic navicular drop (DND). A hierarchical cluster analysis method was used to identify the optimal number of clusters based on these two foot-related kinematic variables. Following identification of the clusters, differences in cluster variables and cross-sectional areas of selected foot muscles assessed using ultrasonography in each cluster were examined. The muscles of interest included the abductor hallucis, flexor hallucis brevis and longus, flexor digitorum brevis and longus, and peroneus longus.

RESULTS

Three subgroups were identified based on foot kinematics during running: cluster 1, lowest NH at initial contact and larger DND; cluster 2, moderate NH at initial contact and smaller DND; and cluster 3, highest NH at initial contact and larger DND. Clusters 1 and 3 had a larger abductor hallucis compared with cluster 2, and cluster 3 had a larger flexor hallucis brevis compared with cluster 2.

SIGNIFICANCE

These subgroups may differ in terms of resistance to and type of running-related injury. Moreover, foot kinematics during running is possibly impacted by the morphology and function of medial intrinsic foot muscles.

Effective Interventions for Improving Functional Movement Screen Scores Among "High-Risk" Athletes: A Systematic Review

BACKGROUND

The Functional Movement ScreenTM (FMSTM) is a tool designed to screen a series of movements that aids in the identification of compensatory fundamental movement patterns, functional limitations, and asymmetrical movement patterns. A previous systematic review and meta-analysis has shown that athletes with an FMSTM score <13-14 are considered "high-risk" and are more likely to be injured. There are discrepancies regarding the efficacy of physical intervention programs in improving FMSTM scores.

PURPOSE

The aim of this systematic review was to assess the role of physical intervention programs in increasing functional movement in "high-risk" athletes as measured by the FMSTM.

STUDY DESIGN

Systematic Review.

METHODS

A computerized search was performed in 2019 according to PRISMA guidelines searching Embase, Science Direct, Ovid, and PubMed. The studies were assessed for quality and risk of bias using the Modified Downs and Black checklist. Participant demographics, intervention routines, and FMSTM scores were extracted from the included studies.

RESULTS

Six studies met the inclusion criteria and demonstrated a fair methodological quality. Comparisons across all studies revealed significant improvement in FMSTM scores following implementation of a variety of physical intervention programs. These programs included those that utilized functional training, foot muscle strengthening, Pilates, core stability training, and resistance movements. Despite variations in the corrective exercises performed, the number of training sessions, and the length of the intervention program, all studies demonstrated an increase in the total FMSTM score following program implementation.

CONCLUSION

The included intervention programs significantly improved total FMSTM scores in "high-risk" athletes. Despite variations in the corrective exercises (interventions) performed, the number of training sessions, and the length of the program, all studies demonstrated a significant increase in the total FMSTM score following program implementation.

Effect of Systematic Corrective Exercises on the Static and Dynamic Balance of Patients with Pronation Distortion Syndrome: A Randomized Controlled Clinical Trial Study

Background:

The purpose of this study was to determine the effect of systematic corrective exercises on the static and dynamic balance of students with pronation distortion syndrome.

Methods:

In this randomized controlled clinical trial study, 30 volunteers were selected and randomly divided into the control and experimental groups (15 subjects per group). The experimental group performed systematic corrective exercises for 12 weeks, while the control group performed the routine exercise. Static and dynamic balance was evaluated before and after the interventions. The data were analyzed using independent and paired t-tests (P < 0.05).

Results:

The results showed significant improvement (P < 0.05) in the static and dynamic balance in the experimental group, but not in the control group. A significant difference was evident between the experimental and control groups in terms of static and dynamic balances, in static balance including Flamingo balance test (42.26 ± 5.35 vs. 10.13 ± 1.92) stabilometr (1.23 ± 0.48 vs. 3.71 ± 1.02), and in dynamic balance including star excursion balance test (anterior direction 82.4 ± 6.2 vs. 66.7 ± 6.9, Posterior-internal direction 87.8 ± 4.7 vs. 69.6 ± 6.3, posterior-external direction 86.06 ± 6.93 vs. 67.2 ± 6.2), stabilometr (3.8 ± 0.6 vs. 11.18 ± 1.8) (P < 0.05 for all variables).

Conclusions:

It can be concluded that systematic corrective exercises improve static and dynamic balance in students with pronation distortion syndrome and it could be recommended as modalities for these people.

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.

Examining the efficacy of short foot exercises as an effective stand-alone treatment for mechanical low back pain associated with foot overpronation

BACKGROUND: Abnormal foot mechanics in foot over-pronation has an identified relationship with mechanical low back pain (MLBP). OBJECTIVE: To explore the use of short foot exercises (SFEs) as a standalone treatment for MLBP with foot over-pronation. METHODS: Forty-six patients with MLBP (PwMLBP) presenting with and foot over-pronation were analyzed. They were randomized into the SFE (short foot exercise), SFE plus traditional physical therapy treatment (SFE+TPT), and control (CG) groups. Functional disability and pain level were measured using the Oswestry Disability Index (ODI) and visual analog scale (VAS), respectively. Ultrasonography measured the cross-sectional area (CSA) of the abductor hallucis (AbdH) muscle. The foot posture and navicular drop (ND) were investigated using the foot posture index-6 (FPI) score and ND test, respectively. RESULTS: The CSA of the AbdH and VAS scores improved significantly (p< 0.001) between the groups, more in the SFE+TPT group than in the SFE group (p< 0.001). The ND, FPI, and ODI measures improved significantly among the groups (p< 0.001), with no significant difference (p> 0.002) between the SFE and SFE+TPT groups. The CG did not show significant differences in the outcome measures (p> 0.002). Based on the effect size, SFEs significantly improved all the variables of interest (d>1). CONCLUSION: SFEs, with or without TPT may offer an effective treatment for PwMLBP with foot over-pronation.

Clinical and radiological outcomes of corrective exercises and neuromuscular electrical stimulation in children with flexible flatfeet: A randomized controlled trial

BACKGROUND

Flexible flatfeet are common among children being scarcely symptomatic requires no specific treatment and resolves spontaneously. However, flexible flatfoot tends to advance and deteriorate overtime and eventually resulting in significant impairments such as plantar fasciitis and patellofemoral pain syndrome.

RESEARCH QUESTION

What is the effect of corrective exercises and neuromuscular electrical stimulation in children with flexible flatfeet?

METHOD

This is a randomized controlled trial with 72 children, seven to twelve yearsold, randomly assigned to either intervention or control group (36 children for each group) and engaged in a four months (3 sessions/week) of corrective exercise and neuromuscular electrical stimulation or corrective exercise and sham neuromuscular electrical stimulation respectively. Assessments of Staheli's arch index (through foot print), navicular drop (through navicular drop test) and radiographic indexes (through anterior-posterior and medio-lateral X-ray) of both feet were performed before and after the intervention programs.

RESULTS

Study groups were comparable with respect to all outcome measures at entry (P > 0.05). Within group comparison showed significant improvements in all measured variables. Further, between groups comparison revealed significant higher improvements (P < 0.05) in right and left feet Staheli's arch index, navicular drop as well as the radiographic indexes in favor of the intervention group.

SIGNIFICANCE

Integration of corrective exercises and neuromuscular electrical stimulation is more effective than exercises alone for providing clinical and radiological improvements in children with flexible flatfeet.

Effects of Two Foot-Ankle Interventions on Foot Structure, Function, and Balance Ability in Obese People with Pes Planus

Obese people are prone to foot deformities such as flat feet. Foot management programs are important to prevent them. This study investigated the effects of two foot-ankle interventions on balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions in obese people with pes planus for four weeks. The experiment was designed as a randomized controlled trial. Twenty-four participants who met the inclusion criteria were selected, and they were randomly assigned to either a short foot group (SFG) or proprioceptive neuromuscular facilitation group (PNFG) according to foot-ankle intervention. Two interventions were commenced three times a week for 20 min over four weeks. The tests were conducted at two intervals: pre-intervention and at four weeks. The tests were conducted in the following order: the patient-specific functional scale test (PSFS), an ultrasound of the plantar fascia, the navicular drop test, balance test, and the four-way ankle strength test. Two groups showed significant differences in balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions between pre-test and post-test (p < 0.05). PNFG had significantly higher dorsiflexor and invertor strength than SFG (p < 0.05). SF and PNF interventions were effective to improve balance ability, foot arch, ankle strength, plantar fascia thickness, and foot functions in obese people with pes planus. Additionally, PNF intervention is more beneficial in increasing the dorsiflexor and invertor strength compared to SF intervention.

Relationship between foot muscle morphology and severity of pronated foot deformity and foot kinematics during gait: A preliminary study

BACKGROUND

The morphology of foot muscles that support the medial longitudinal arch differs between normal and pronated feet. The degree to which the difference depends on the severity of the pronated foot deformity is unclear. In the clinical setting, however, to reduce the pronated deformity, muscle-strengthening exercises are performed.

RESEARCH QUESTION

Does a relationship exist between foot muscle morphology and severity of the pronated foot deformity and foot kinematics during gait?

METHODS

Using the six-item foot posture index (FPI-6), 26 study participants were assessed for their foot posture and divided into two groups of 13 participants each based on the FPI-6 score: pronated foot group (with a score of 6-9) and highly pronated foot group (with a score of 10-12). Select foot muscles were scanned with ultrasonography, and muscle thicknesses were measured. The following were the muscles of interest: abductor hallucis, flexor hallucis brevis and longus, flexor digitorum brevis and longus, and peroneus longus. Foot kinematic data during gait was collected using a three-dimensional motion capture system as a dynamic navicular drop.

RESULTS

No between-group differences were noted for muscle thickness and dynamic navicular drop. However, the abductor hallucis and flexor hallucis brevis thicknesses were correlated with the dynamic navicular drop, but not with the severity of the pronated foot deformity.

SIGNIFICANCE

In individuals with pronated foot deformity, more developed abductor hallucis and flexor hallucis brevis muscles may reduce the dynamic navicular drop that represents the degree of medial longitudinal arch deformation during the stance phase of gait.

Intrinsic foot muscle strengthening exercises with electromyographic biofeedback achieve increased toe flexor strength in older adults: A pilot randomized controlled trial

BACKGROUND

Toe flexor strength is important for preventing older adults from falling. Although intrinsic foot muscles are the main determinants of toe flexor strength, exercises for strengthening these muscles are difficult for older adults. This study therefore aimed to determine whether the use of electromyographic biofeedback helps older adults to perform intrinsic foot muscle strengthening exercises.

METHODS

This randomized controlled trial had two parallel arms. Participants were randomly allocated to the control group or the electromyographic biofeedback group. Control participants performed two progressive intrinsic foot muscle strengthening exercises twice a week for 6 weeks. Participants in the other group performed these exercises assisted by electromyographic biofeedback. Primary outcome measures were changes in toe flexor strength and the timed up-and-go and functional reach tests (the latter two being balance tests).

FINDINGS

Altogether, 23 older adults were randomized to the control group (n = 12) or the electromyographic biofeedback group (n = 11). After the 6-week intervention, toe flexor strength on the dominant side increased in both groups (P < 0.017). However, toe flexor strength on the nondominant side increased only in the electromyographic biofeedback group (P < 0.017), with a large effect size of 1.5. There were no changes in the two balance tests. Three of the control group and two of the electromyographic biofeedback group were lost to follow- up.

INTERPRETATION

Our results indicate that, the use of electromyographic biofeedback can enhance the effect of intrinsic foot muscle strengthening exercises on the nondominant side in older adults.

CLINICAL TRIAL REGISTRATION NUMBER

UMIN000036521.

Modification of Pronated Foot Posture after a Program of Therapeutic Exercises

Working on the intrinsic musculature of the foot has been shown to be effective in controlling pronation. However, the potential coadjuvant effect that involving other muscle groups might have on foot posture remains unknown. The aim was, therefore, to assess whether a 9-week intrinsic and extrinsic foot and core muscle strength program influenced foot posture in pronated subjects. The participants were 36 healthy adults with pronated feet that were randomly assigned to two groups. The experimental group (n = 18) performed a strengthening exercise protocol for 9 weeks (two sessions of 40 min per week), while the control group (n = 18) did not do these exercises. After 9 weeks, the foot posture index (FPI) scores of the two groups were analyzed to detect possible changes. The FPI at the baseline was 8.0 ± 1.5. After the 9 weeks, the experimental group showed significantly reduced FPI from 8.1 ± 1.7 to 6.4 ± 2.1 (p = 0.001), while the control group had the same score as pre-intervention (FPI 8 ± 1.2, p = 1.0). The FPI scores showed no significant differences by sex. Strengthening of the intrinsic and extrinsic foot and core muscles contributed to improving foot posture in adults, reducing their FPI by 1.66 points.

Impact of Short Foot Muscle Exercises on Quality of Movement and Flexibility in Amateur Runners

The flexibility and proper functioning of all myofascial chains are crucial for athletes, especially for long-distance runners. Due to the continuity of the myofascial structures, restrictions in one part of the body may cause excessive tension in others. The aim of our study was to evaluate the influence of short foot muscle exercises on muscle flexibility and the quality of movement patterns in amateur runners. Eighty long-distance runners, aged 20–45, were randomly divided into two groups: Group 1 (n = 48) and Group 2 (n = 32). Participants in Group 1 performed foot exercises daily for six weeks. Subjects in Group 2 were without any intervention. At baseline and after six weeks, the quality of movement patterns with the Functional Movement Screen and muscle flexibility was evaluated. In Group 1, significantly higher Functional Movement Screen values in individual tasks and in the total score were noted after six weeks. The total score increased from 17 to 18 points (Median (Me) ± half of interquartile range (IQR/2) (Standard Error of Measurement - SEM) 17 ± 1.5 (0.23) at baseline and 18 ± 1.5 (0.24) after six weeks) (p < 0.01), whereas in Group 2, its level remained at 16 points (Me ± IQR/2 (SEM) 16 ± 1.5 (0.31) at baseline and 16 ± 1.25 (0.31) after six weeks). In Group 1, the significant improvement in muscle flexibility was noted (e.g., results for external rotation muscles: (Mean ± SD (SEM) 60.3 ± 0.4 (1.50) at baseline and 62.4 ± 10.3 (1.49) after six weeks) (p = 0.005). In Group 2, significant improvement was observed only for one task in the Active straight leg raise test (p = 0.005 and 0.02). During the measurement of external rotation muscles, a significant decrease in flexibility was observed (Mean ± SD (SEM) 60.1 ± 9.0 (1.60) at baseline and 58.0 ± 8.5 (1.51) after six weeks) (p = 0.001). Plantar short foot muscle exercises may improve muscle flexibility in the upper parts of the body within myofascial chains and influence the quality of fundamental movement patterns. Such exercises may be beneficial for all physically active people and can be performed as part of overall fitness programmes. Moreover, including such exercises in daily training routines of long-distance runners, as well as by athletes in other sport disciplines is also recommended.

Randomized Clinical Trial: The Effect of Exercise of the Intrinsic Muscle on Foot Pronation

Background: There is little scientific evidence regarding the effectiveness of strengthening exercises on the foot's intrinsic musculature in improving the lower limb on the statics and dynamics in healthy individuals. Method: To evaluate the effect on foot posture with regard to the reinforcement of the short foot exercise (SFE) compared to another without a recognized biomechanical action, which we called the "non-biomechanical function" (NBF) exercise. A randomized clinical trial was carried out with 85 asymptomatic participants with a bilateral Foot Posture Index (FPI) greater than 6 points. An experimental group (n = 42) did SFE training and a control group (n = 43) carried out NBF exercises. The foot posture was evaluated twice via the navicular drop (ND) test, and the FPI was assessed on the day of inclusion in the study (pre-intervention) and after four weeks of training (post-intervention). Results: Statistically significant values were not found in foot posture between the experimental and the control groups when comparing before and after the training. However, the foot posture was modified in both groups with respect to its initial state, and the ND value decreased. Conclusions: SFE could be considered a useful tool to deal with pathologies whose etiology includes excessive pronation of the foot.

Effects of plantar intrinsic foot muscle strengthening exercise on static and dynamic foot kinematics: A pilot randomized controlled single-blind trial in individuals with pes planus

BACKGROUND

No reliable evidence has confirmed whether plantar intrinsic foot muscle strengthening exercises improve static and dynamic foot kinematics in individuals with pes planus.

RESEARCH QUESTION

Does the short-foot exercise affect static foot alignment and foot kinematics during gait in individuals with pes planus?

METHODS

This was a randomized controlled single-blind trial involving 20 participants with pes planus who were randomly allocated to a short-foot exercise group (exercise) or a control group (controls). Exercise patients performed a progressive short-foot exercise three times per week for 8 weeks; controls received no intervention. Before and after the 8-week intervention, foot kinematics during gait, including dynamic navicular drop-the difference between navicular height at heel strike and the minimum value-and the time at which navicular height reached its minimum value were assessed, using three-dimensional motion analysis. We assessed static foot alignment by foot posture index and navicular drop test, and the thickness of the intrinsic and extrinsic foot muscles using ultrasound. All measurements were performed by one investigator (KO) blinded to the participants' allocation.

RESULTS

After the 8-week intervention in the exercise group, foot posture index scores with regard to calcaneal inversion/eversion improved significantly (p < 0.05). Moreover, the time required for navicular height to reach the minimum value decreased significantly (p < 0.01).

SIGNIFICANCE

For individuals with pes planus, the short-foot exercise effectively corrected static foot alignment and temporal parameters of foot kinematics during gait. This temporal change, which shortens the time for navicular height to reach its minimum value, indicates an improved windlass mechanism. Therefore, short-foot exercise might effectively prevent or treat injuries related to the pes planus alignment.

Core muscles' endurance in flexible flatfeet: A cross - sectional study

OBJECTIVE

Flexible flatfoot is a common deformity in adults that has been thought to be a causative factor of a lot of lower limb injuries and back pain. Core muscles act as stabilizers for the trunk and weak core places a person at greater risk of low back pain and lower limb injuries. We aimed to compare the core muscles' endurance between individuals with and without flatfeet.

METHODS

Thirty subjects with bilateral flexible flatfeet (study group) were compared with thirty healthy subjects (control group). Navicular drop test was used to evaluate the medial longitudinal arch. Modified back extensors, modified flexion and lateral muscles' endurance tests were used to evaluate the endurance of the core muscles.

RESULTS

The lateral muscles' endurance time in the flatfeet group was found to be significantly lower than that of the healthy group on both sides (p=0.0001). However, no significant difference was found in the trunk flexors' (p=0.15) and trunk extensors' (p=0.27) endurance time between both groups.

CONCLUSIONS

Impairment of the lateral core muscles' endurance was observed in subjects with bilateral flexible flatfeet which may predispose to low back pain and other lower limb injuries in those subjects.

Effects of Short-Foot Exercises on Foot Posture, Pain, Disability, and Plantar Pressure in Pes Planus

CONTEXT

Pes planus is a prevalent chronic condition that causes foot pain, disability, and impaired plantar load distribution. Short-foot exercises are often recommended to strengthen intrinsic foot muscles and to prevent excessive decrease of medial longitudinal arch height.

OBJECTIVE

To investigate the effects of short-foot exercises on navicular drop, foot posture, pain, disability, and plantar pressures in pes planus.

DESIGN

Quasi-experimental study.

SETTING

Biomechanics laboratory.

PARTICIPANTS

A total of 41 participants with pes planus were assigned to the short-foot exercises group (n = 21) or the control group (n = 20).

INTERVENTION

Both groups were informed about pes planus, usual foot care, and appropriate footwear. Short-foot exercises group performed the exercises daily for 6 weeks.

MAIN OUTCOME MEASURES

Navicular drop, Foot Posture Index, foot pain, disability, and plantar pressures were assessed at the baseline and at the end of 6 weeks.

RESULTS

Navicular drop, Foot Posture Index, pain, and disability scores were significantly decreased; maximum plantar force of midfoot was significantly increased in short-foot exercises group over 6 weeks (P < .05). No significant differences were determined between the baseline and the sixth week outcomes in control group (P > .05).

CONCLUSIONS

Six-week short-foot exercises provided a reduction in navicular drop, foot pronation, foot pain, and disability and increment in plantar force of medial midfoot in pes planus.

How to Evaluate and Improve Foot Strength in Athletes: An Update

The foot is a complex system with multiple degrees of freedom that play an essential role in running or sprinting. The intrinsic foot muscles (IFM) are the main local stabilizers of the foot and are part of the active and neural subsystems that constitute the foot core. These muscles lengthen eccentrically during the stance phase of running before shortening at the propulsion phase, as the arch recoils in parallel to the plantar fascia. They play a key role in supporting the medial longitudinal arch, providing flexibility, stability and shock absorption to the foot, whilst partially controlling pronation. Much of the foot rigidity in late stance has been attributed to the windlass mechanism – the dorsiflexion of the toes building tension up in the plantar aponeurosis and stiffening the foot. In addition, recent studies have shown that the IFM provide a necessary active contribution in late stance, in order to develop sufficient impedance in the metatarsal-phalangeal joints. This in turn facilitates the propulsive forces at push-off. These factors support the critical role of the foot in providing rigidity and an efficient lever at push-off. During running or sprinting, athletes need to generate and maintain the highest (linear) running velocity during a single effort in a sprinting lane. Acceleration and sprinting performance requires forces to be transmitted efficiently to the ground. It may be of particular interest to strengthen foot muscles to maintain and improve an optimal capacity to generate and absorb these forces. The current evidence supports multiple exercises to achieve higher strength in the foot, such as the “short foot exercise,” doming, toes curl, towing exercises or the more dynamic hopping exercises, or even barefoot running. Their real impact on foot muscle strength remains unclear and data related to its assessment remains scarce, despite a recognized need for this, especially before and after a strengthening intervention. It would be optimal to be able to assess it. In this article, we aim to provide the track and field community with an updated review on the current modalities available for foot strength assessment and training. We present recommendations for the incorporation of foot muscles training for performance and injury prevention in track and field.

Translation, cross-cultural adaptation, and reliability of the Foot Posture Index (FPI-6) - Brazilian version

Background: The Foot Posture Index (FPI) is a quick, easy, and reliable clinical assessment for measuring foot posture variation in different environments. The aim of the study was to translate the FPI into Brazilian Portuguese and assess its inter and intra-observer reliability. Methods: The cross-cultural adaptation of the 6-item version of the FPI (FPI-6) was accomplished using standard guidelines. Forty-two volunteers participated in the reliability process, assessed by two examiners and at three different occasions, evaluated using the intraclass correlation coefficient (ICC). The agreement between reliability assessments was investigated by the standard error of measurement (SEM) and the minimal detectable change (MDC₉₀). Results: The Brazilian version of the FPI-6 showed excellent inter and intraobserver reliability for the dominant (ICC = 0.91 and 0.90) and nondominant lower limb (ICC = 0.94 and 0.92). The agreement was considered excellent for SEM with values representing less than 5% in relation to the total FPI-6 score. The MDC₉₀ showed that changes in the score greater than 1.82 (for interobserver) and 1.90 (for intraobserver) can be considered as clinical changes in foot posture. Conclusion: The Brazilian version of the FPI-6 has proved reliable in terms of inter and intraobserver reliability and can therefore be used both in clinical practice and in scientific research.

The effect of additional activation of the plantar intrinsic foot muscles on foot kinematics in flat-footed subjects

BACKGROUND

Strengthening exercises of the plantar intrinsic foot muscles (PIFMs) are often prescribed to flat-footed subjects because of the capacity of the PIFMs to support the medial longitudinal arch (MLA). However, it is unclear whether the capacity of the PIFMs to support the MLA is enough to change the foot kinematics in flat-footed subjects. To confirm this, the current study examined changes in foot kinematics in flat-footed subjects during standing and gait accompanied by changes in the activity of the PIFMs.

METHODS

Eighteen flat-footed subjects were randomly assigned to an electrical stimulation group (ESG) or a control group (CG). In the ESG, electrical stimulation to the PIFMs was applied during standing and gait to simulate reinforcement of the PIFMs. Then, foot kinematics were measured using 3D motion analysis, and the amount of change from baseline (when no electrical stimulation was applied) was compared between the groups.

RESULTS

In the gait analysis, the time at which the MLA height reached its minimum value was significantly later in the ESG, with no reduction in the MLA height at that time. Moreover, forefoot inversion angle and tibial external rotation angle were significantly increased in the ESG at that time. In the standing analysis, there were no significant differences between the groups.

CONCLUSION

The results revealed that in flat-footed subjects, the PIFMs have the capacity to support the MLA enough to change foot kinematics during gait. Strengthening these muscles may be effective in preventing or treating lower extremity overuse injuries related to flat-foot alignment.

The Influence of Plantar Short Foot Muscle Exercises on the Lower Extremity Muscle Strength and Power in Proximal Segments of the Kinematic Chain in Long-Distance Runners

The aim of this study was to evaluate the influence of plantar short foot muscles exercises on the performance of lower extremities in long-distance runners. 47 long-distance runners aged 21-45 years took part in this study. The participants were divided into two groups based on baseline measurement of Foot Posture Index: Group 1 (n=27) with neutral foot and Group 2 (n=20) with slight and increased pronation. The participants performed the exercises daily for 6 weeks. The knee flexors and extensors torque, work, and power on Isokinetic Dynamometer and Running-Based Anaerobic Sprint Test (RAST) were checked at baseline and after 6 weeks of exercises. Higher values of peak torque of knee flexors were observed. This change was statistically significant at high load with angular velocity 90°/s (73.55 Nm at baseline and 89.05 Nm after 6 weeks) and 160°/s (69.40 Nm at baseline and 79.00 Nm after 6 weeks) in Group 2. In both groups higher values of maximum power were noted. Participants in Group 2 achieved lower values in each 35-metre run time and higher values of power. In Group 2 there was significant improvement of total time (35.26 s at baseline and 34.79 s after 6 weeks) compared to Group 1 (37.33 s at baseline and 37.56 s after 6 weeks). Exercises strengthening short foot muscles may improve energy transfer through body segments and increase strength and values of generated power. They should be included as a part of daily training programme of runners. This study was registered in the Australian New Zealand Clinical Trials Registry (ANZCTR). Registration number: ACTRN12615001200572.

Contributions of foot muscles and plantar fascia morphology to foot posture

BACKGROUND

The plantar foot muscles and plantar fascia differ between different foot postures. However, how each individual plantar structure contribute to foot posture has not been explored. The purpose of this study was to investigate the associations between static foot posture and morphology of plantar foot muscles and plantar fascia and thus the contributions of these structures to static foot posture.

METHODS

A total of 111 participants were recruited, 43 were classified as having pes planus and 68 as having normal foot posture using Foot Posture Index assessment tool. Images from the flexor digitorum longus (FDL), flexor hallucis longus (FHL), peroneus longus and brevis (PER), flexor hallucis brevis (FHB), flexor digitorum brevis (FDB) and abductor hallucis (AbH) muscles, and the calcaneal (PF1), middle (PF2) and metatarsal (PF3) regions of the plantar fascia were obtained using a Venue 40 ultrasound system with a 5-13 MHz transducer.

RESULTS

In order of decreasing contribution, PF3 > FHB > FHL > PER > FDB were all associated with FPI and able to explain 69% of the change in FPI scores. PF3 was the highest contributor explaining 52% of increases in FPI score. Decreased thickness was associated with increased FPI score. Smaller cross sectional area (CSA) in FHB and PER muscles explained 20% and 8% of increase in FPI score. Larger CSA of FDB and FHL muscles explained 4% and 14% increase in FPI score respectively.

CONCLUSION

The medial plantar structures and the plantar fascia appear to be the major contributors to static foot posture. Elucidating the individual contribution of multiple muscles of the foot could provide insight about their role in the foot posture.