Search Results (45)

Foot muscles contribute to impact attenuation and propulsion during running, yet the effects of repeated toe-flexor contractions and associated strength loss on running biomechanics remain poorly understood. The primary objective of this randomized crossover study was to investigate the acute effects of repeated concentric and isometric toe-flexor contractions on hallux flexion strength, used as an index of fatigue; secondary analyses examined running ground-reaction-force outcomes. Nineteen recreationally active adults completed two interventions one week apart: concentric toe-flexor contractions and isometric toe-flexor contractions combined with electrical stimulation of the medial longitudinal arch. Hallux flexion strength and ground reaction forces during treadmill running at 9 and 12 km·h⁻¹ were assessed before and after each intervention. The concentric protocol reduced hallux flexion strength by 20%, whereas the isometric protocol did not. None of the hypothesis-driven running biomechanical outcomes, including contact duration, impact peak force, active peak force, and vertical stiffness, changed significantly after either protocol. Exploratory secondary analyses suggested changes in selected leg stiffness and impulse variables. In recreationally active adults, repeated concentric toe-flexor contractions induced measurable neuromuscular fatigue, whereas the isometric protocol did not significantly reduce hallux flexion strength; biomechanical changes were limited to exploratory outcomes. Full article

This study evaluated the long-term changes induced by wearing minimalist footwear (MF) during activities of daily living (ADLs) on the plantar footprint and postural stability in healthy adults. In this randomized clinical trial, a total of 95 healthy adults were recruited; 90 participants completed the protocol and were analyzed in either an experimental group (EG, n = 45), which wore MF for at least 5 h per day over a 6-month period, or a passive control group (CG, n = 45). Plantar pressure distribution (forefoot, rearfoot, and total contact areas), static stability (center of pressure (CoP) displacement under open-eyes and closed-eyes conditions), and dynamic stability (forward reach test) were assessed using a force platform at baseline and post-intervention. A self-reported questionnaire and an adverse event record were also completed by the EG. Statistical analysis was carried out using a repeated-measures analysis of variance (ANOVA) and a paired Student’s t-test; statistical significance level was set at p < 0.05. The Group $\times$ Time interaction analysis revealed no statistically significant between-group differences across the evaluated parameters. However, within-group analysis showed a significant increase in CoP displacement under the open-eye condition in the CG ($p=0.037$), indicating a decline in baseline postural efficiency, whereas the EG maintained structural and posturographic stability. Regarding user feedback, comfort (44.4%) was highlighted as the primary advantage, aesthetics (77.8%) was the main drawback, and 70% of the participants intended to continue using MF. Only two minor, transient adverse events were recorded. In conclusion, a 6-month program of MF use during ADLs did not produce any statistically significant changes in plantar footprint or stability in healthy adults. Full article

Background: Knee pain, proprioceptive deficits, and muscle weakness brought about by articular degeneration in knee osteoarthritis (OA) can cause postural instability and gait asymmetry. Arm swing plays a major role in balance control during human walking. However, few studies have examined the arm movement and gait stability in knee OA. Therefore, the purpose of this study is to investigate the gait asymmetry in upper and lower limb movement and to understand the overall movement pattern during walking in people with knee osteoarthritis. Methods: Thirty-five people with knee OA and twenty-four age-matched controls were enrolled in this study. The arm swing amplitude, gait biomechanics, and spatiotemporal parameters during walking were measured using a Vicon motion capture system incorporating two AMTI force plates. The differences between the knee OA and control groups were analyzed using independent t-tests. Results: The knee OA patients walked with a slower, smaller step and lower arm swing amplitude. The asymmetries of step time, foot progression angle, and total arm swing amplitude were significantly greater in the knee OA group than in the controls (p < 0.05). There was no significant difference in the mean value of step width and the foot progression angle and the asymmetry of step length and the knee adduction moment between the groups. Conclusions: This study demonstrates that the pathological changes in the lower limbs in knee OA are intrinsically reflected in the upper limbs through diagonal coordination. Asymmetry of arm swing and foot progression angle may be key for understanding OA-related instability. Full article

Background: The superficial plantar-medial release (S-PMR) refers to a group of surgical procedures involving the release of the plantar aponeurosis and adjacent medial plantar soft tissues that are used in selected cases of plantar fasciitis and cavovarus foot deformity. The procedure aims to address pain and contracture of the plantar aponeurosis and intrinsic foot muscles, which may contribute to pathological foot alignment and gait instability. Due to the close proximity of highly variable neurovascular structures in the plantar region, precise anatomical knowledge and a patient-specific, personalized approach are essential to reduce the risk of iatrogenic injury during surgery. This study defined procedure-specific anatomical “low-risk” and “high-risk” zones. Methods: From the initial forty-two included feet, one specimen was excluded due to insufficient tissue quality, leaving forty-one specimens for analysis. The plantar aponeurosis, origins of the abductor hallucis muscle and regional neurovascular structures were analyzed. Distances between key landmarks were measured. Results: Abductor hallucis origins I and IV were present in all specimens, while origins II and III showed variable presence. Subdivision of muscle origin I was observed and was associated with the course of the medial calcaneal nerve. The medial calcaneal nerve demonstrated the closest proximity to origin I (3.2 mm) whereas both the medial and lateral plantar nerves showed close proximity to origin II (3 mm and 5.3 mm). Conclusion: Significant interindividual variability exists in the plantar region, highlighting the need for a personalized, anatomy-based approach for patients considered for surgical intervention. Anatomical “high-risk” zones were identified between origin I and the medial calcaneal nerve and near origin II by the bifurcation of the tibial nerve and posterior tibial artery. Anatomical “low-risk” zones were defined as dorsal regions at the calcaneus between origin I and the tibial neurovascular bundle, as well as medial areas near the malleolus. Full article

The common marmoset (Callithrix jacchus) is a New World monkey that was introduced as an animal model in biomedical research in the 1960s. In addition to their use in biomedical research, marmosets are also often housed in zoos. Their arboreal lifestyle requires a well-functioning foot. When confronted with foot injuries, the veterinarians responsible for the medical care of captive marmosets request easily available, clearly presented anatomical data. In addition, this anatomical data will be very valuable to gain a better understanding of marmosets’ locomotion. The scarce books and atlases on the anatomy of this species provide only line drawings, use archaic nomenclature, and/or exclude details on the foot. Color photographs were taken during the subsequent steps of the dissections of four common marmoset cadavers. Both dorsal and plantar views of the crural muscles with influence on the tarsus and foot, as well as the intrinsic foot musculature, are described in the guiding text. Contradictions with the available literature and a comparison with the rhesus monkey are included. A few remarkable differences with the rhesus monkey’s foot were observed. Furthermore, noteworthy additions to the existing literature are made. It is concluded that this work could serve as an anatomical basis for medical interventions on injured feet and for further locomotor studies. Full article

Background: Handball involves unilateral, high-demand actions that increase injury risk. The Windlass mechanism (WM) is a position-dependent plantar fascia tensioning system, activated by dorsiflexion of the first metatarsophalangeal joint, which increases medial longitudinal arch stiffness and contributes to foot stability. WM activation can be mechanically simulated using hallux wedges to induce controlled dorsiflexion, allowing graded engagement of the mechanism under standardized conditions. The primary aim of this study was to investigate how different wedge inclinations, with and without visual biofeedback, affect foot muscle activity during squats in elite female handball players. Methods: Seventeen elite female handball players performed squats at 65% of one-repetition maximum under six conditions combining three wedge inclinations (0°, 10°, 30°) with the presence or absence of visual biofeedback. Electromyographic activity (RMS and %MVC) of intrinsic and extrinsic foot muscles was recorded. Results: A significant increase in left abductor hallucis activation with the 10° wedge without biofeedback. Visual biofeedback significantly increased RMS and %MVC in intrinsic foot muscles and increased RMS in the left gastrocnemius (p < 0.05). No significant interaction was observed between wedge inclination and biofeedback. Conclusions: Controlled activation of the WM via hallux wedges and the use of visual biofeedback modulate foot muscle activity during squats. These strategies may be considered in training programs aimed at improving foot stability and reducing injury risk in elite female handball players. Full article

Background: Intrinsic foot muscle strengthening and orthotic devices such as toe spacers are commonly used to improve foot alignment and function. However, evidence regarding the combined effects of strengthening exercises and interdigital spacers remains limited. Objective: To examine whether adding a silicone toe spacer to a foot strengthening exercise program provides additional benefits compared with exercise alone. Design: Randomized controlled trial. Setting: University biomechanics laboratory. Participants: Twenty-five healthy adults (mean age 23.8 ± 1.3 years) without lower limb injury or neurological disorders were randomly allocated to one of two intervention groups. Interventions: Participants performed a six-week foot strengthening program (22 sessions). One group performed exercises alone, while the second group performed the same exercises while wearing a silicone interdigital toe spacer. Main outcome measures: The primary outcome was hallux valgus angle. Secondary outcomes included active and passive hallux range of motion (ROM), ankle dorsiflexion ROM (weight-bearing lunge test), navicular drop, and postural stability during single-leg stance assessed using center-of-pressure (CoP) measures. Results: Both groups demonstrated improvements over time in hallux valgus angle (p = 0.001, η² = 0.361), active hallux range of motion (p < 0.001, η² = 0.545), and ankle dorsiflexion (p < 0.001). However, no significant between-group differences were observed for the primary outcome or most secondary outcomes. A significant time × group interaction was observed only for passive hallux range of motion (p = 0.040, η² = 0.170), indicating greater improvement in the exercise-only group. Navicular drop and postural stability variables did not change significantly. Conclusions: A six-week foot strengthening program improved hallux alignment, hallux mobility, and ankle dorsiflexion in healthy adults. The addition of a silicone toe spacer did not provide additional short-term benefits compared with exercise alone. Full article

Background: The origin of hallux abducto valgus (HAV) is considered to be multifactorial; however, evidence regarding the factors involved in its development is scattered and often contradictory. Understanding the factors that contribute to the onset of HAV is crucial for informing both prevention and clinical management strategies. This review aims to explore the etiological factors associated with the development of HAV. Methods: A literature search was conducted in PubMed, Embase, Web of Science and Scopus. The search included observational studies that investigated etiological or risk factors related to the development of HAV. Methodological quality was assessed using the Joanna Briggs Institute (JBI) checklists, and the level of evidence was classified according to the Oxford Centre for Evidence-Based Medicine (OCEBM). Results: A total of 36 observational studies (20 cross-sectional and 16 case–control) were included, involving 14,500 participants, predominantly females. Genetic evidence indicated strong familial aggregation and variants in collagen- and extracellular matrix-related genes as potential hereditary determinants. The most consistent biomechanical factors were first-ray hypermobility, abnormal foot pronation and reduced activity of the abductor hallucis muscle. Additionally, female sex, older age and prolonged use of narrow or inadequate footwear were identified as recurring predictive variables. Overall, the findings support a complex etiological model based on the interaction of intrinsic and extrinsic factors. Conclusions: The development of HAV appears to be determined by the interaction of genetic, structural and biomechanical factors that alter first-ray stability and forefoot function. Current evidence supports a multifactorial etiological model with a strong hereditary component and higher susceptibility in women. Longitudinal studies employing standardized methods are needed to establish causal relationships and quantify the relative contribution of each factor. Full article

Background: Flatfoot is an alteration of the normal structure of the foot, characterized by a partial or total reduction of the medial longitudinal plantar arch, valgus deformity of the heel, and abduction of the forefoot. While treatments often include strengthening of the intrinsic foot muscles, evidence of its efficacy in adults with flatfoot remains limited. Objectives: The main objective of this review was to evaluate the effects of strengthening the plantar intrinsic muscles in adults with flatfoot. Methods: Searches were conducted in PubMed, Embase, Cochrane, PEDro, and Web of Science databases up to October 2023. The review protocol was developed and followed according to the PRISMA Extension for Scoping Reviews (PRISMA-ScR) guidelines. Studies included were those published on intrinsic muscle strengthening in adult populations. A qualitative synthesis of all included articles was performed, along with a quantitative sub-analysis of randomized controlled trials and a critical methodological assessment. Results: Eleven studies involving a total of 374 participants were selected. Most studies identified the “short foot exercise” as the optimal exercise for isolating and training the plantar intrinsic foot muscles. The most commonly analyzed variables were the Foot Posture Index and the Navicular Drop Test. Conclusions: Strengthening the plantar intrinsic muscles enhances the height of the medial longitudinal arch, improves hindfoot posture and balance, and increases hallux abductor muscle activity. This strengthening, whether achieved through short foot exercises alone or in combination with other techniques, is effective in treating adult flatfoot. Current literature suggests that a duration of 4–6 weeks may be sufficient to achieve beneficial outcomes. Full article

Pitching requires effective transfer of ground reaction force (GRF), and structural breakdown of the medial longitudinal arch (MLA) may influence glenohumeral internal rotation (IR) deficits. This study investigated whether changes in foot morphology of the stride leg and soft tissue characteristics are associated with loss of IR during repeated pitching. Fifteen male college pitchers completed 60 pitches in a simulated game. IR range of motion (IRROM) was assessed before and after pitching. The navicular height, mechanical properties of the abductor hallucis (AbH) and plantar fascia, and GRF were measured at multiple time points. Correlation analysis and a linear mixed model were used to identify predictors of IRROM change. The mean change in shoulder IRROM during pitching was −21.9° ± 8.4°. IRROM and navicular height decreased significantly over time. The AbH elasticity increased throughout the pitching sequence. Greater reductions in IRROM appeared related to a higher vertical GRF (p = 0.021) and increased AbH elasticity (p = 0.046). Vertical GRF was unrelated to fastball velocity (p = 0.260), whereas anteroposterior GRF correlated with fastball velocity (p = 0.038). Morphological and mechanical changes in the stride leg, particularly within the support of the MLA, can influence IRROM. Reducing vertical GRF and stress on the AbH may help preserve the IRROM without compromising performance. Full article

Background/Objectives: The popularity of barefoot and minimalist footwear training has increased in recent years, yet its impact on foot strength, morphology, and functional outcomes remains unclear, particularly in strength-training contexts beyond running-focused studies. Although some biomechanical and anecdotal evidence exists, no systematic review has specifically addressed the effects of foot-specific strength training interventions performed barefoot or with minimalist footwear. This review aimed to evaluate the effects of barefoot and minimalist footwear strength training interventions on foot muscle structure, force production, and neuromuscular function in healthy and athletic adults. Methods: A systematic review was conducted in accordance with the PRISMA and PICOS guidelines (PROSPERO number CRD420251134329). Comprehensive database searches were performed in July 2025. Eligible studies included barefoot or minimalist strength interventions in healthy and sportive adults, assessing outcomes related to foot muscle morphology, strength, functional performance, or neuromuscular adaptations. Methodological quality was evaluated using the PEDro and MINORS scales. Results: Seven studies involving 213 participants met the inclusion criteria. Most interventions led to significant improvements in intrinsic and extrinsic foot muscle volume, medial arch function, toe flexor strength, and neuromuscular control. Adaptations were particularly evident in interventions combining strength, balance, and agility exercises over multiple weeks. However, heterogeneity in protocols and outcome measures limited comparability. Some studies reported morphological gains without proportional improvements in strength or function. Conclusions: Barefoot and minimalist strength training can elicit beneficial morphological and functional adaptations in the foot. Nevertheless, inconsistencies in study design, small sample sizes, absence of follow-up assessment and lack of standardized protocols highlight the need for high-quality research to guide training recommendations beyond running-focused populations. Full article

Background: Reduction in intrinsic foot muscle strength may impair physical performance and increase the risk of falls. Aim: The aim of this study is to analyze the relationship between hallux flexion strength, assessed through the PGT, for physical performance and fall risk in Chilean older adults. Methods: A cross-sectional, descriptive–correlational study was conducted with 188 community-dwelling older adults (89.3% women). Participants’ sociodemographic and anthropometric information was also collected. Hallux plantar flexion strength was assessed using the Paper Grip Test (PGT). Physical performance was evaluated with the Short Physical Performance Battery (SPPB), and fall risk was assessed using the Timed Up and Go (TUG) and Single-Leg Stance Test (SLS). Pearson’s correlation coefficients were calculated for the overall sample, as well as separately for sex. Results: Significant positive correlations were observed between PGT and the total SPPB score for both the right foot (r = 0.178; p = 0.008) and the left foot (r = 0.175; p = 0.009). Additionally, moderate correlations were found between PGT and SLS time (right r = 0.316; p < 0.001; left r = 0.397; p < 0.001), and an inverse correlation was observed between PGT and TUG execution time (right r = −0.372; p < 0.001; left r = −0.393; p < 0.001). Regression models showed that TUG and SLS significantly predicted PGT performance, explaining 17% (R² = 0.17) and 20% (R² = 0.20) of the variance for the right and left foot, respectively. Conclusions: Hallux plantar flexion strength is significantly associated with physical performance and fall risk. The simplicity, low cost, and clinical utility of the PGT support its use as a screening tool for early detection of functional decline. Full article

Background: Stability deficit is one of the most common and disabling signs of multiple sclerosis; therefore, balance training is essential for most patients. Intrinsic foot muscles are a key element in stability, but their influence in multiple sclerosis patients has not been assessed. Objective: The aim of the study was to assess the efficacy of intrinsic foot muscle training on stability in patients with multiple sclerosis. Methodology: A randomized single-blind clinical trial was conducted using a sample of multiple sclerosis patients divided into a control group (CG) and an intervention group (IG). Subjects in the intervention group completed an eight-week intrinsic foot muscles training programme. Static and dynamic stability were measured using the Activities-specific Balance Confidence questionnaire (AsBC), the Four Square Step Test (FSST), the Frailty and Injuries: Cooperative Studies of Intervention Techniques (FICSIT), and the Six Spot Step Test (SSST). Pre- and post-intervention outcomes and differences between groups were calculated. Results: The amount of change comparing pre- and post-intervention results was −0.94 (CG) and 5.59 (IG) in the AsBC questionnaire (p 0.17); −1.0 (CG) and −1.5 (IG) in the FSST (p 0.72); 0.0 for both groups in FICSIT (p 0.629); and −1.5 (CG) and −2.0 (IG) in SSST (p 0.692). Conclusions: Intrinsic foot muscle training produces positive changes in dynamic stability and self-perceived confidence in multiple sclerosis patients. Full article

Müller-Weiss disease is a rare condition of osteonecrosis of the lateral navicular with dorsal midfoot pain. The predominant treatment discussed in the literature is surgery. This report focuses on a single case using conservative treatment, including pain medication, ethylene vinyl acetate custom orthotics, motion control shoes, physiotherapy for strengthening intrinsic foot muscles, and weight management. The primary complaint from the patient was midfoot pain limiting activities of daily living. After application of conservative treatment modalities and 10 months of follow-up, bilateral midfoot pain decreased from 9/10 to 2/10. To the authors’ knowledge, this is the first case report of successful conservative treatment of bilateral Müller-Weiss disease in a patient with multiple comorbidities using pain medication, ethylene vinyl acetate custom orthotics, motion control shoes, physiotherapy, and weight management. Full article