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

The impact of corrective exercises, kinesiology taping, and mechanical correction on pain and foot shape in women with hallux valgus

Background

This study aimed to assess the effect of corrective exercises and exercises supplemented by kinesiology taping or an orthosis on pain and foot alignment in women with hallux valgus (HV).

Methods

Eighty-two women with HV were randomly divided into groups: E (n = 24) who exercised for 12 weeks; EKT (n = 18) who exercised and used kinesiology taping on HV; EMC (n = 15) who performed exercise and used an orthosis to correct their big toe position; and CHV (25 women with HV without therapy). Additional control group C: (n = 31) women with normal hallux. The Wejsflog index, Clarke's angle, alpha and beta angles, and pain intensity in the big toe area were assessed at the beginning and after therapy.

Results

The Wejsflog index was significantly lower in women with HV and increased significantly after therapy in the E and EKT groups. Clarke's angle did not differ between women with and without HV, and Clarke's angle did not change after therapy. The HV angle decreased significantly in groups E and EKT but was still significantly greater than that in group C. The fifth toe varus angle did not differ between women with and without HV and decreased significantly in the right foot after therapy in group E. Pain in the HV area decreased significantly in all groups undergoing therapy.

Conclusion

Women with HV have a greater forefoot width, but their longitudinal arch and fifth toe position do not differ. Exercises significantly reduce pain and improve hallux alignment. Combining exercises with kinesiology taping or an orthosis does not increase the therapeutic effect. Although the observed effects of conservative therapy are promising, it should be remembered that long-term effects have not been studied.

Trial registration

The Australian New Zealand Clinical Trials Registry (ACTRN12621000902897).

The Effect of Flexible Flatfoot on the Running Function in School-Age Children

Flexible flatfoot is common among school-age children and significantly affects walking efficiency, balance stability, and joint-movement coordination in children. The demands on the skeletal structure and muscle function are increased during running; however, the impact of a flexible flatfoot on children's running capabilities is unclear. In this study, we aimed to investigate the effects of flexible flatfoot on the running function of school-age children. Participants with flat feet (n = 28) and typical feet (n = 27) ran on a flat surface at their chosen maximum pace. At the same time, the kinematic and dynamic parameters of their lower limb joints were monitored. A two-sample statistical analysis assessed the differences in the lower limbs' three-dimensional kinematic and dynamic parameters during running. The findings revealed a significant reduction in running velocity, stride length, and frequency, and an increased proportion in the support phase (p < 0.05) in children with flexible flat feet. The navicular drop time decreased, whereas the dynamic navicular drop height increased (p < 0.05). A notable decrease in the maximum plantar flexion and eversion torque, power, and power absorption of the ankle joint was observed (p < 0.01). Furthermore, the maximum flexion torque of the knee and hip joints and hip joint power absorption decreased (p < 0.05). The peak ground reaction force in the anteroposterior directions was reduced (p < 0.01). These results indicate that flexible flatfoot can impair the running efficiency of school-age children and lead to diminished motor stability and reduced propulsive and braking capabilities.

Efficacy of Functional Re-Education as a Treatment for Infantile Flexible Flatfoot: Systematic Review

BACKGROUND

Flexible pediatric flatfoot is an anatomical presentation of the foot that is common in children, and its functional impact raises long-term uncertainty. Functional re-education includes strengthening and stretching exercises for the intrinsic and extrinsic musculature of the foot, proposed as an effective conservative treatment. However, to date, there is no systematic review examining its effectiveness in the pediatric population. This systematic review aims to evaluate the effectiveness of functional re-education as a conservative treatment for flexible pediatric flatfoot, determining which exercises are most effective.

METHODS

A search (PROSPERO: CRD42023391030) was conducted across six databases, resulting in an initial total of 327 studies. Of these, 11 randomized controlled trials (RCTs) met the inclusion criteria, resulting in a sample of 419 children aged 6 to 14 years with a diagnosis of flexible flatfoot. The evaluated studies present variations in diagnostic criteria, types of exercises, and treatment duration.

RESULTS

The results indicate that functional re-education is effective in improving the symptomatology and functionality of the foot in children. In particular, exercises targeting the intrinsic musculature proved to be among the most effective treatments, improving the structural development of the medial longitudinal arch. The reviewed literature recommends a minimum treatment duration of eight weeks.

CONCLUSIONS

Functional re-education represents an effective conservative treatment option for flexible flatfoot in children, positioning it as the treatment of choice for this condition.

Is a keystone Bone Anomaly the Main Cause of Flatfoot (Pes Planus)?

BACKGROUND

Flatfoot (pes planus) is a decrease or loss of longitudinal medial arch height. The cause of symptomatic flatfoot occurring in adolescents is still unclear. In this study, the relationship between adolescent pes planus and foot bone shape was investigated. For this purpose, the volume and superficial area data of the foot bones of adolescent individuals with flatfoot deformity and individuals without any foot deformity were compared.

METHODS

Between September 2022 and June 2023, 30 individuals with adolescent pes planus with a medial arch angle greater than 145 degrees and 30 individuals without any foot deformity were included in the study. Computed tomography (CT) images of the participants' feet were obtained with a General Electric brand IQ model 32 detector CT device with a section thickness of 0.625 mm in accordance with the bone protocol. Using the 3D Slicer program on CT images, foot bones were segmented and the volume and surface area ratios of each foot bone were determined.

RESULTS

Cuneiforme mediale and cuneiforme intermediale volume ratios in individuals with flatfoot deformity decreased by 14% and 24%, respectively, compared with the control group ( P <0.05). Cuneiforme mediale and cuneiforme intermediale superficial area ratios were found to be 10% and 30% lower in the flatfoot group compared with the control group, respectively ( P <0.05). There was no difference in the volume and superficial area ratios of other foot bones between the groups ( P >0.05).

CONCLUSIONS

The study results suggest that symptomatic adolescent flatfoot deformity may be associated with developmental anomalies of the os cuneiforme mediale and os cuneiforme intermedium.

Effects of Plantar Fascia Release and the Use of Foot Orthoses Affect Biomechanics of the Medial Longitudinal Arch of the Foot: A Cadaveric Study

OBJECTIVE

The aim of the study is to evaluate the effect of minimally invasive ultrasound-guided fascial release and a foot orthoses with first metatarsal head cutout on the biomechanics of the medial longitudinal arch of the foot in cadaveric specimens.

DESIGN

A cross-sectional study was designed (20 body donors). Anthropometric measurements of the foot, foot posture index, and the windlass test and force were measured in different conditions: unloaded, loaded position, with foot orthoses, after a 25% plantar fascia release and after a 50% release.

RESULTS

For the anthropometric measurements of the foot, differences were found in foot length ( P = 0.009), arch height ( P < 0.001), and midfoot width ( P = 0.019) when comparing the unloaded versus foot orthoses condition. When foot orthoses were compared with 25% plantar fascial release, differences were found in foot length ( P = 0.014) and arch height ( P < 0.001). In the comparison with 50% plantar fascial release, differences were found in the arch height ( P < 0.001). A significant interaction between foot orthoses condition and grades was found in the arch height during the windlass test ( P = 0.021).

CONCLUSIONS

The results indicate that the presence of foot orthoses leads to a significant increase in arch height compared with other conditions. Furthermore, when plantar fascia release is performed, the arch does not exhibit any signs of collapse.

Effects of short foot training on foot posture in patients with flatfeet: A systematic review and meta-analysis

BACKGROUND

With lifestyle changes, the prevalence of flatfoot is increasing year by year, with a prevalence of 29%. Flatfoot will lead to an inevitable injury and reduce the quality of life. Short foot exercises can enhance the strength of the intrinsic muscles of the foot and improve the symptoms of flatfoot. However, there is controversy regarding its specific efficacy.

OBJECTIVE

This meta-analysis quantitatively evaluates the effect of short foot training on patients with flatfeet and provides evidence to inform the clinical approach to short foot training in patients with flat feet.

METHODS

A total of eight databases were searched, including CNKI, WANFANG, VIP, and CBM in Chinese and PubMed, Cochrane, Web of Science, and Embase in English. The timeframe for searching the literature was March 2023 for each database build. English database search terms and search formulas were: (flat foot OR talipes valgus OR talipes calcaneovalgus) AND (short foot exercises OR physical therapy OR neurophysiotherapy).

RESULTS

The current pooled results show no significant difference in the improvement of the navicular drop test and foot posture index with short foot exercises compared to controls; only short foot exercises greater than 6 w showed a significant improvement in the navicular drop test, and sensitivity analysis showed a significant improvement in the foot posture index with short foot exercises.

CONCLUSION

This systematic review and meta-analysis showed that short foot exercises need a larger sample size to find their effect on improving flat feet; the duration of the intervention is a factor. As most studies are currently unclear whether the participants were patients with flat feet or asymptomatic individuals with flat feet the disease syndrome in patients with flatfoot may also be a factor.

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.

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.

Reversing the Mismatch With Forefoot Striking to Reduce Running Injuries

Recent studies have suggested that 95% of modern runners land with a rearfoot strike (RFS) pattern. However, we hypothesize that running with an RFS pattern is indicative of an evolutionary mismatch that can lead to musculoskeletal injury. This perspective is predicated on the notion that our ancestors evolved to run barefoot and primarily with a forefoot strike (FFS) pattern. We contend that structures of the foot and ankle are optimized for forefoot striking which likely led to this pattern in our barefoot state. We propose that the evolutionary mismatch today has been driven by modern footwear that has altered our footstrike pattern. In this paper, we review the differences in foot and ankle function during both a RFS and FFS running pattern. This is followed by a discussion of the interaction of footstrike and footwear on running mechanics. We present evidence supporting the benefits of forefoot striking with respect to common running injuries such as anterior compartment syndrome and patellofemoral pain syndrome. We review the importance of a gradual shift to FFS running to reduce transition-related injuries. In sum, we will make an evidence-based argument for the use of minimal footwear with a FFS pattern to optimize foot strength and function, minimize ground reaction force impacts and reduce injury risk.

Fat Is Consistently Present within the Plantar Muscular Space of the Human Foot—An Anatomical Study

Background and Objectives: The foot comprises of active contractile and passive connective tissue components, which help maintain stability and facilitate movement during gait. The role of age- or pathology-related degeneration and the presence of fat within muscles in foot function and pain remains unclear. The existence of fat has to date not been quantified or compared between individuals according to age, sex, side or subregion. Materials and Methods: 18 cadaveric feet (mean age 79 years) were sectioned sagittally and photographed bilaterally. Fat in the plantar muscular space of the foot (PMSF) was quantified through the previously validated manual fat quantification method, which involved observing photographs of each section and identifying regions using OsiriX. Fat volume and percentage was calculated using a modified Cavalieri’s method. Results: All feet had fat located within the PMSF, averaging 25.8% (range, 16.5–39.4%) of the total PMSF volume. The presence of fat was further confirmed with plastination and confocal microscopy. Conclusions: These findings suggest that fat within the PMSF is a consistent but highly variable finding in elderly cohorts. Fat within the foot muscles may need to be considered a norm when comparing healthy and non-healthy subjects, and for therapeutic interventions to the foot. Further work is required to understand in detail the morphological and mechanical presence of fat in the foot, and compare these findings with pathological cohorts, such as sarcopenia. Additionally, future work should investigate if fat may compensate for the degeneration of the intrinsic muscles of the foot, with implications for both the use of orthotics and pain management.

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.

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.

The effect of changing foot progression angle using real-time visual feedback on rearfoot eversion during running

Atypical rearfoot in/eversion may be an important risk factor for running-related injuries. Prominent interventions for atypical rearfoot eversion include foot orthoses, footwear, and taping but a modification derived from gait retraining to correct atypical rearfoot in/eversion is lacking. We aimed to investigate changes in rearfoot in/eversion, subtalar pronation, medial longitudinal arch angle, and selected lower limb joint biomechanics while performing toe-in/toe-out running using real-time visual feedback. Fifteen female runners participated in this study. Subjects performed toe-in/toe-out running using real-time visual feedback on foot progression angle, which was set ±5° from habitual foot progression angle. 3D kinematics of rearfoot in/eversion, subtalar supination/pronation, medial longitudinal arch angle, foot progression angle, hip flexion, ab/adduction and internal/external rotation, knee flexion, ankle dorsiflexion, and ankle power were analyzed. A repeated-measures ANOVA followed by pairwise comparisons was used to analyze changes between three conditions. Toe-in running compared to normal and toe-out running reduced peak rearfoot eversion (mean difference (MD) with normal = 2.1°; p<0.001, MD with toe-out = 3.5°; p<0.001), peak pronation (MD with normal = -2.0°; p<0.001, MD with toe-out = -3.4; p = <0.001), and peak medial longitudinal arch angle (MD with normal = -0.7°; p = 0.022, MD with toe-out = -0.9; p = 0.005). Toe-out running significantly increased these kinematic factors compared to normal and toe-in running. Toe-in running compared to normal running increased peak hip internal rotation (MD = 2.3; p<0.001), and reduced peak knee flexion (MD = 1.3; p = 0.014). Toe-out running compared to normal running reduced peak hip internal rotation (MD = 2.5; p<0.001), peak hip ab/adduction (MD = 2.5; p<0.001), peak knee flexion (MD = 1.5; p = 0.003), peak ankle dorsiflexion (MD = 1.6; p<0.001), and peak ankle power (MD = 1.3; p = 0.001). Runners were able to change their foot progression angle when receiving real-time visual feedback for foot progression angle. Toe-in/toe-out running altered rearfoot kinematics and medial longitudinal arch angle, therefore supporting the potential value of gait retraining focused on foot progression angle using real-time visual feedback when atypical rearfoot in/eversion needs to be modified. It should be considered that changes in foot progression angle when running is accompanied by changes in lower limb joint biomechanics.

Evaluation of the Validity, Reliability, and Kinematic Characteristics of Multi-Segment Foot Models in Motion Capture

This study aimed to evaluate the validity and reliability of our new multi-segment foot model by measuring a dummy foot, and examine the kinematic characteristics of our new multi-segment foot model by measuring the living body. Using our new model and the Rizzoli model, we conducted two experiments with a dummy foot that was moved within a range from -90 to 90 degrees in all planes; for the living body, 24 participants performed calf raises, gait, and drop jumps. Most three-dimensional (3D) rotation angles calculated according to our new models were strongly positively correlated with true values (r > 0.8, p < 0.01). Most 3D rotation angles had fixed biases; however, most of them were in the range of the limits of agreement. Temporal patterns of foot motion, such as those in the Rizzoli model, were observed in our new model during all dynamic tasks. We concluded that our new multi-segment foot model was valid for motion analysis and was useful for analyzing the foot motion using 3D motion capture during dynamic tasks.

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.

Effects of the Short Foot Exercise With Neuromuscular Electrical Stimulation on Navicular Height in Flexible Flatfoot in Thailand: A Randomized Controlled Trial

OBJECTIVES

Flatfoot, or low medial longitudinal arch, contributes to back and lower extremity injuries and is caused by weak abductor hallucis (AbdH) muscles. The purpose of this study was to investigate the effects of short foot exercise (SFE) alone or with neuromuscular electrical stimulation (NMES) on navicular height, the cross-sectional area (CSA) of the AbdH muscle, and AbdH muscle activity in flexible flatfoot.

METHODS

Thirty-six otherwise healthy people with flexible flatfoot were randomly assigned to a group that received SFE with placebo NMES treatment (the control group) or a group that received both SFE and NMES treatment (the experimental group). Each group received 4 weeks of treatment (SFE alone or SFE with NMES). Navicular height, the CSA of the AbdH muscle, and AbdH muscle activity were assessed before and after the intervention.

RESULTS

No significant differences were found in navicular height or the CSA of the AbdH muscle between the control and experimental groups, while AbdH muscle activity showed a statistically significant difference between the groups (SFE=73.9±11.0% of maximal voluntary isometric contraction [MVIC]; SFE with NMES=81.4±8.3% of MVIC; p<0.05). Moreover, the CSA of the AbdH muscle showed a statistically significant increase after treatment in the SFE with NMES group (pre-treatment=218.6±53.2 mm2; post-treatment=256.9±70.5 mm2; p<0.05).

CONCLUSIONS

SFE with NMES was more effective than SFE alone in increasing AbdH muscle activity. Therefore, SFE with NMES should be recommended to correct or prevent abnormalities in people with flexible flatfoot by a physiotherapist or medical care team.