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

Foot Posture Index Does Not Correlate with Dynamic Foot Assessment Performed via Baropodometric Examination: A Cross-Sectional Study

BACKGROUND

Clinicians employ foot morphology assessment to evaluate the functionality of the method and anticipate possible injuries. This study aims to correlate static foot posture and the dynamic barefoot evaluation in a sample of healthy adult participants.

METHODS

The foot posture was evaluated using the Foot Posture Index-6 (FPI-6) and the dynamics were evaluated through baropodometric examination. Two operators independently assessed the participants' foot posture through FPI-6, and then a dynamic evaluation was performed by asking them to walk 8 times across a platform. One hundred participants (mean age: 32.15 ± 7.49) were enrolled.

RESULTS

The inter-rater agreement between the two assessors was found to be excellent. The majority of the feet belonged to the 0 < FPI < 4 class (32%), followed by the 4 < FPI < 8 (31%) and the FPI > 8 ranges (19.5%). Our "area of contact" analysis showed a significant poor correlation between FPI and total foot, midfoot, and the second metatarsophalangeal joint (MTPJ) (-0.3 < r < 0). Regarding "force" parameters, the analysis showed a poor correlation between the midfoot, hallux, and the second toe (-0.2 < r < 2); finally the "pressure" analysis showed a poor correlation between FPI, the fourth MTPJ, and the second toe (-0.2 < rs < 0.3) and a moderate correlation between the hallux (r = 0.374) and the fifth MTPJ (r = 0.427).

CONCLUSIONS

This study emphasizes the constrained correlation between static foot posture observation and dynamic barefoot examination.

Proposals for talonavicular joint assessment using ultrasound imaging and its reliability and validity

[Purpose] We aimed to develop a noninvasive specific ultrasonographic assessment of the talonavicular joint during loading to facilitate the analysis of treatment of flatfoot. [Participants and Methods] Sixty healthy participants underwent ultrasound imaging of the talonavicular joint while sitting and standing. The talonavicular angle was defined as the intersection of the line connecting the navicular and talar heads and the line connecting the talar head and sustentaculum tali. Talonavicular coverage was assessed using X-ray images of 15 participants. [Results] Ultrasonographic assessment of the talonavicular joint showed a lateral shift of the navicular relative to the head of the talus from sitting to standing. The talonavicular angle was significantly larger when standing than in the sitting position. The difference in talonavicular angle values between sitting and standing significantly correlated with the differences in the talonavicular coverage values. [Conclusion] We showed that ultrasonographic talonavicular angle assessment has good reliability and moderate validity for detecting significant alignment changes in the talonavicular joints due to loading. In the future, this evaluation method should be performed before and after exercise therapy to assess and develop appropriate exercise therapy for flatfoot.

Evidence for Intrinsic Foot Muscle Training in Improving Foot Function: A Systematic Review and Meta-Analysis

OBJECTIVE

To critically assess the literature focused on strength training of the intrinsic foot muscles (IFMs) and resulting improvements in foot function.

DATA SOURCES

A search of electronic databases (PubMed, CINAHL, Scopus, and SPORTDiscus) was completed between January 2000 and March 2022.

STUDY SELECTION

Randomized control trials with an outcome of interest and at least 2 weeks of IFM exercise intervention were included. Outcomes of interest were broadly divided into 5 categories of foot posture (navicular drop and Foot Posture Index), namely: balance, strength, patient-reported outcomes, sensory function, and motor performance. The PEDro scale was used to assess the methodologic quality of the included studies with 2 independent reviewers rating each study. Studies with a PEDro score greater than 4/10 were included.

DATA EXTRACTION

Data extracted by 2 independent reviewers were design, participant characteristics, inclusion and exclusion criteria, type of intervention, outcomes, and primary results. We performed a random-effects meta-analysis to analyze the difference between intervention and control groups for each outcome when at least 2 studies were available. Standardized mean differences (SMDs) describe effect sizes with 95% CIs (SMD ranges). When the CI crossed zero, the effect was not significant.

DATA SYNTHESIS

Thirteen studies were included, and IFM exercise interventions were associated with decreasing navicular drop (SMD range = 0.37, 1.83) and Foot Posture Index (SMD range = 1.03, 1.69) and improving balance (SMD range = 0.18, 1.86), strength (SMD range = 0.06, 1.52), and patient-reported outcomes for disability (SMD range = 0.12, 1.00), with pooled effect sizes favoring the IFM intervention over the control. The IFM exercises were not superior (SMD range = -0.15, 0.66) for reducing pain. We could not perform a meta-analysis for sensory function and motor performance, as only 1 study was available for each outcome; however, these results supported the use of IFM strength training.

CONCLUSIONS

Strength training of the IFMs was helpful for patients in improving foot and ankle outcomes.

The effects of short foot exercises to treat flat foot deformity: A systematic review

BACKGROUND

Studies on the effects of performing short foot exercises (SFEs) on the medial longitudinal arch (MLA) have been inconclusive.

OBJECTIVE

This study aimed to conduct a systematic review of the effects of SFEs.

METHODS

'SFE' and 'intrinsic foot muscle' were keywords used to search for randomized controlled trials. One researcher screened relevant articles based on their titles and abstracts, and two independent researchers closely read the texts, accepting nine studies for inclusion. Outcomes, intervention duration, frequency, and the number of interventions were investigated.

RESULTS

Of 299 potential studies identified, the titles and abstracts of 211 studies were reviewed, and 192 were excluded. The full texts of 21 studies were obtained and evaluated according to inclusion and exclusion criteria. Nine studies met the inclusion criteria. Six studies concerning the MLA were identified, with four reporting MLA improvement. There was no consensus concerning the number and frequency of SFEs performed, and the mechanism of MLA improvement was unclear. MLA improvement was observed in participants who undertook ⩾ 5 weeks of interventions.

CONCLUSIONS

The results suggest that performing SFEs for ⩾ 5 weeks is effective in improving the MLA. Randomized controlled trials with details concerning the number and frequency of treatments are required.

Effect of Arch Height Flexibility in Individuals With Flatfoot on Abductor Hallucis Muscle Activity and Medial Longitudinal Arch Angle During Short Foot Exercises

Flatfoot presents decreased medial longitudinal arch (MLA), and such foot deformity involves intrinsic foot muscles dysfunction. Flatfoot can be classified into flexible and stiff types according to arch height flexibility (AHF). Short foot exercise (SFE) is an intrinsic foot muscle strengthening exercise, which is reportedly effective against flatfoot. However, its effectiveness against flexible or stiff types in flatfoot is unclear. We examined the effect of AHF in individuals with flatfoot during abductor hallucis muscle (AbH) activity and medial longitudinal arch during SFE. Foot alignment was assessed using the arch height index during standing, and individuals with flatfoot (N = 16) were recruited. The AbH activity and MLA angle during SFE while maintaining single-leg standing were assessed. The relationship between AHF and AbH activity and between AHF and MLA angle ratio was analyzed using correlation coefficients. Additional correlations between AHF and AbH activity were observed with the outliers removed. There were no correlations between AHF and AbH muscle activity and between AHF and MLA angle ratio. However, with the 2 outliers removed, moderate correlations between AHF and AbH activity were significant (r = 0.64, p = .01). AbH activity during SFE increased in individuals with flatfoot for high AHF (flexible type). Thus, SFE may be more effective for individuals with flatfoot having a high AHF. These findings may be helpful when making decisions for surgery and rehabilitation.

Auswirkungen des Trainings der intrinsischen Fußmuskulatur bei Patienten*innen mit Sprunggelenkinstabilität – ein narrativer Review

Hintergrund Sprunggelenkdistorsionen stellen eine der häufigsten Verletzungen im Sport dar und können sich als chronische Sprunggelenkinstabilität manifestieren. In der Therapie und Prävention hat sich ein sensomotorischer Trainingsansatz der sprunggelenkumgebenden Strukturen als wirksam erwiesen. Es gibt Hinweise, dass auch ein Training der intrinsischen Fußmuskulatur beispielsweise die Balance verbessern kann.

Ziel Ziel dieses narrativen Reviews ist die Darstellung der Evidenz eines Trainings der intrinsischen Fußmuskulatur bei Patient*innen mit Sprunggelenkinstabilität.

Methode Im Januar 2022 wurde in den Datenbanken PubMed, Cochrane Library, EBSCOhost, PEDro, SPONET und BISp-Surf eine systematische Literaturrecherche durchgeführt, die durch eine Freihandsuche ergänzt wurde. Dabei sollten Metaanalysen, Systematic Reviews und Interventionsstudien inkludiert werden, die Effekte einer Trainingsform der intrinsischen Fußmuskulatur bei Patient*innen mit Sprunggelenkinstabilität untersuchten. Die qualitative Bewertung der Literatur und Evidenz erfolgte anhand des Risk-of-Bias-Tools (RoB-Tool) des Cochrane Handbook sowie angelehnt an das GRADE-System.

Ergebnisse Fünf randomisierte kontrollierte Studien mit insgesamt 150 Proband*innen wurden inkludiert. Vier Studien nutzten die Short-Foot Exercise (SFE), eine Studie die Towel-Curl Exercise (TCE) und eine wandte ein Training der Zehen an. Drei Studien wiesen einen großen, signifikant positiven Effekt (p<0,05) der SFE auf die subjektive Instabilität auf. Die SFE und das Zehentrainingsprogramm hatten signifikant positive Effekte (p<0,05) auf die Balance, wobei die Einbeziehung der SFE in ein Trainingsprogramm zu keinem Vorteil führte. Eine Studie stellte signifikant positive Auswirkungen (p<0,05) der SFE auf die Somatosensibilität fest. Alle 3 Trainingsformen führten zu deutlichen, signifikanten (p<0,05) Verbesserungen funktioneller Aspekte.

Schlussfolgerung Es zeigen sich positive Effekte durch das Training der intrinsischen Fußmuskulatur bei Patient*innen mit Sprunggelenkinstabilität auf die subjektive Instabilität, Balance, Somatosensibilität sowie auf funktionelle Aspekte. Effektive Trainingsformen scheinen die SFE und ein Zehentraining zu sein, diese könnten eine sinnvolle Ergänzung zur konventionellen Therapie darstellen. Die Qualität der Evidenz ist jedoch zu gering, um eine klare Empfehlung aussprechen zu können.

Effects of the Short-Foot Exercise on Foot Alignment and Muscle Hypertrophy in Flatfoot Individuals: A Meta-Analysis

This study aimed to conduct a meta-analysis of randomized controlled trials to examine the effects of the short-foot exercise (SFE) compared to foot orthosis or other types of interventions. Eligibility criteria involved participants with flatfoot engaging in the SFE compared to other forms of intervention or control groups without specific intervention. Relevant studies published before the end of June 2022 were identified from databases. A meta-analysis was performed by calculating the mean differences (MD) and standard MD (SMD) using the random effects model. Six trials with 201 patients (out of 609 records) that met selection criteria were reviewed. Five of the six trials implemented distinct interventions in the control group such as shoe insoles and muscle strengthening exercises, while in the remaining trial, controls received no intervention. The SFE group significantly reduced the navicular drop test (NDT) values (MD: -0.23; 95% confidence interval: -0.45 to -0.02; p = 0.04) and the foot posture index (FPI-6) score (MD: -0.67; 95% confidence interval: -0.98 to -0.36; p < 0.0001) when compared to the control group. The muscle hypertrophy did not differ significantly between the groups. The SFE may contribute more benefits than other intervention as it affects flatfoot individuals' foot alignment. Hence, the SFE is recommended as a beneficial dynamic support when facing flatfoot problems.

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.

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.

Validity of ultrasound imaging for intrinsic foot muscle cross-sectional area measurements demonstrated by strong agreement with MRI

PURPOSE

Intrinsic foot muscles maintain foot structural integrity and contribute to functional movement, posture and balance. Thus, assessing intrinsic foot muscle size and strength are important. Magnetic resonance imaging (MRI) has been shown to accurately image the individual muscles but is costly and time consuming. Ultrasound (US) imaging may provide an alternative that is less costly and more readily available. The purpose of this study was to investigate the validity and intratester reliability of US imaging in measuring intrinsic foot muscle size in comparison to MRI.

METHODS

US and MRI were employed to measure the intrinsic foot muscle size involving 35 participants (females = 13; males = 22). The scanned intrinsic foot muscles included the flexor hallucis brevis (FHB), abductor hallucis (ABDH), flexor digitorum brevis (FDB), quadratus plantae (QP) and abductor digiti minimi (ADM). Pearson product correlation (r), intraclass correlation coefficients (ICC), standard error of the measurement (SEm) and minimal detectable difference (MDD) were calculated.

RESULTS

High correlations were detected between the US and MRI cross-sectional area (CSA) measurements (r = .971 to 0.995). Test reliability was excellent for both MRI and US (ICC = 0.994 to 0.999). Limits of agreement between MRI and US measurements from ranged from 5.7 to 12.2% of muscle size. SEm values for US ranged from 0.026 to 0.044 cm2, while the SEm for MRI ranged from 0.018 to 0.023 cm2. MDD values for US ranged from 0.073 to 0.122 cm2, while MRI ranged from 0.045 to 0.064 cm2.

CONCLUSIONS

US appears to be a valid and reliable alternative to MRI when measuring intrinsic foot muscle CSA. While US is less costly and more readily available, the MRI results were shown to be slightly more precise.

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.

The Impact of Foot Orthoses and Exercises on Pain and Navicular Drop for Adult Flatfoot: A Network Meta-Analysis

Background: Adult flatfoot leads to injury and decreased quality of life. The most widely applied noninvasive approaches are wearing foot orthoses or exercising. Both interventions raise controversy about reducing pain and neutralizing foot posture. This study investigated the impact of foot orthoses and exercise on pain and navicular drop (present for foot posture). Methods: Four databases were used: MEDLINE, PubMed, Web of Science, and Cochrane, from the earliest records to November 2020. Randomized controlled studies focused on adult flatfoot that evaluated the effect of exercise and foot orthoses on pain and navicular drop were extracted. We used data analysis to estimate the relative effect of heterogeneity using I² and publication bias using funnel plots. Results: Ten studies were identified through to November 2020. Active interventions (AIs) were exercise and exercise combined with foot orthoses; passive interventions (PIs) were foot orthoses and added stretching. Both AIs and PIs decreased pain significantly (SMD −0.94, 95% CI −1.35, −0.54 and SMD −1.4, 95% CI −1.87, −0.92). The AIs reduced pain level better than PIs. Controversially, no treatment was found to affect navicular drop. Conclusion: Both exercise and foot orthoses can reduce pain but not realign foot posture. Exercise alone or combined with foot orthoses showed a better effect on adult flatfoot than only wearing foot orthoses. Active intervention was shown to have better efficacy in reducing pain than passive intervention.

Hip-Focused Neuromuscular Exercise Provides Immediate Benefits in Foot Pronation and Dynamic Balance: A Sham-Controlled Cross-Over Study

CONTEXT

Knowledge on how to utilize a kinetic chain approach in foot and ankle rehabilitation is important.

OBJECTIVE

The aim of this study was to investigate the immediate effects of hip-focused neuromuscular exercise on foot pronation and single-leg neuromuscular control.

DESIGN

Cross-over study.

SETTING

University laboratory.

PARTICIPANTS

This cross-over study included 44 asymptomatic volunteers with foot pronation.

INTERVENTIONS

All participants performed (1) a hip-focused neuromuscular exercise and (2) a sham exercise in randomized order.

MAIN OUTCOME MEASURES

Foot pronation was assessed by the navicular drop test, and lower-extremity neuromuscular control was assessed by the Modified Star Excursion Balance Test and frontal plane projection angle during single-leg squat before and after the experiments.

RESULTS

Navicular drop test scores were significantly lower after the hip-focused neuromuscular exercise than after the sham exercise (mean difference [95% CI] = 2.84 [-1.08 to 6.77], P = .003). Modified Star Excursion Balance Test scores in the anterior (P = .008), posteromedial (P = .04), and posterolateral (P < .001) directions were significantly increased after hip-focused neuromuscular exercise. No statistically significant condition × time interaction was found for the frontal plane projection angle (P > .05). However, a main effect of time (P = .003) indicated that less dynamic knee valgus occurred during single-leg squat after both experiments.

CONCLUSIONS

Hip-focused neuromuscular exercise produced immediate alterations in foot pronation and dynamic balance. Thus, the hip-focused neuromuscular exercise may be used to control foot posture in foot rehabilitation integrated with a kinetic chain approach and could be an effective prevention and treatment strategy.

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.

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.

Feasibility and Preliminary Efficacy of a Foot-Ankle Exercise Program Aiming to Improve Foot-Ankle Functionality and Gait Biomechanics in People with Diabetic Neuropathy: A Randomized Controlled Trial

Foot-ankle strengthening and mobility exercises are part of international guideline recommendations for people at risk of diabetic foot disease. We examined the feasibility and preliminary efficacy of a 12-week foot-ankle exercise program on clinical, functional and biomechanical outcomes in people with diabetic neuropathy (DPN). We randomly allocated 30 people with DPN to usual care (control) or usual care plus a supervised exercise program (intervention). For feasibility, we assessed recruitment rate and participant adherence and satisfaction. For program efficacy, we assessed baseline to 12-week changes in daily physical activity level, gait speed, tactile sensitivity, ankle range of motion, DPN symptoms, quality of life, foot health and functionality, foot strength and plantar pressure during gait, using paired t-tests (p < 0.05). In 52 weeks, we recruited 45 eligible participants (0.90/week). Program adherence was 80% and participants’ satisfaction had a mean (SD) of 4.57 (0.70) out of 5. The intervention group significantly improved on toes strength, contact time during gait and DPN symptoms, and peak forefoot pressures increased over time; controls showed significantly increased heel peak pressures and force. The exercise program was feasible, based on a moderate recruitment rate and an adherent and satisfied population, and the intervention showed several positive preliminary effects over time compared to usual care.