Relation between foot arch index and ankle strength in elite gymnasts: a preliminary study

Toe Box Shape of Running Shoes Affects In-Shoe Foot Displacement and Deformation: A Randomized Crossover Study

BACKGROUND

Long-distance running is popular but associated with a high risk of injuries, particularly toe-related injuries. Limited research has focused on preventive measures, prompting exploration into the efficacy of raised toe box running shoes.

PURPOSE

This study aimed to investigate the effect of running shoes with raised toe boxes on preventing toe injuries caused by distance running.

METHODS

A randomized crossover design involved 25 male marathon runners (height: 1.70 ± 0.02 m, weight: 62.6 + 4.5 kg) wearing both raised toe box (extended by 8 mm along the vertical axis and 3 mm along the sagittal axis) and regular toe box running shoes. Ground reaction force (GRF), in-shoe displacement, and degree of toe deformation (based on the distance change between the toe and the metatarsal head) were collected.

RESULTS

Wearing raised toe box shoes resulted in a significant reduction in vertical (p = 0.001) and antero-posterior (p = 0.015) ground reaction forces during the loading phase, with a notable increase in vertical ground reaction force during the toe-off phase (p < 0.001). In-shoe displacement showed significant decreased movement in the forefoot medial (p < 0.001) and rearfoot (medial: p < 0.001, lateral: p < 0.001) and significant increased displacement in the midfoot (medial: p = 0.002, lateral: p < 0.001). Impact severity on the hallux significantly decreased (p < 0.001), while impact on the small toes showed no significant reduction (p = 0.067).

CONCLUSIONS

Raised toe box running shoes offer an effective means of reducing toe injuries caused by long-distance running.

Effects of tDCS on Foot Biomechanics: A Narrative Review and Clinical Applications

In recent years, neuro-biomechanical enhancement techniques, such as transcranial direct current stimulation (tDCS), have been widely used to improve human physical performance, including foot biomechanical characteristics. This review aims to summarize research on the effects of tDCS on foot biomechanics and its clinical applications, and further analyze the underlying ergogenic mechanisms of tDCS. This review was performed for relevant papers until July 2023 in the following databases: Web of Science, PubMed, and EBSCO. The findings demonstrated that tDCS can improve foot biomechanical characteristics in healthy adults, including proprioception, muscle strength, reaction time, and joint range of motion. Additionally, tDCS can be effectively applied in the field of foot sports medicine; in particular, it can be combined with functional training to effectively improve foot biomechanical performance in individuals with chronic ankle instability (CAI). The possible mechanism is that tDCS may excite specific task-related neurons and regulate multiple neurons within the system, ultimately affecting foot biomechanical characteristics. However, the efficacy of tDCS applied to rehabilitate common musculoskeletal injuries (e.g., CAI and plantar fasciitis) still needs to be confirmed using a larger sample size. Future research should use multimodal neuroimaging technology to explore the intrinsic ergogenic mechanism of tDCS.

Do Arch Height and Arch Stiffness Relate to Physical Performance in Adult Men?

Foot arch plays an important role in bearing body weight, absorbing ground reaction forces and maintaining balance, and its structure and function are bound to have a profound effect on physical activities and sports. Arch height and arch stiffness are 2 factors that represent the structure and function of the arch. Therefore, the purpose of this study was to explore the associations of arch height and arch stiffness with physical performance. A total of 56 men (aged 49.00 ± 7.95 years, mean body mass index [BMI] 26.80 ± 3.75 kg/m²) participated in this study. A 3-dimensional laser scanner was employed to obtain foot structure information of each participant, from which the arch height index (AHI) and arch stiffness index (ASI) were computed. Physical performance measures including agility, power, and proprioception were tested in a random order. The results indicated that the stepping forward and backward and vertical jump that represent agility and force respectively were negatively and significantly associated with AHI (r = -0.27, p = .045; r = -0.35, p = .009). When adjusted for age and BMI, only height of vertical jump was found to be correlated significantly with AHI (r = -0.29, p = .040); while no significant relationships were observed between physical performance measures and ASI. Multivariate linear regression analysis showed that AHI, age, and BMI can effectively predict the height of vertical jump. This study demonstrates that there is a negative correlation between arch height and muscle power of lower limbs in adult men.

The relationship between knee-ankle muscle strength and performance tests in young female adults with flexible pes planus

Background

A decrease in muscular activation of the knee and ankle is one of the primary reasons for pes planus. The muscle strength of the knee and ankle in patients with pes planus may affect the performance tests which consists of daily life activities. The aim of the study was to determine the relationship between knee and ankle muscle strength with performance tests in young female adults with flexible pes planus. In addition, we also aimed to observe whether the severity of pes planus affects the ankle muscle strength and performance test scores. We carried out a cross-sectional single-center study. The muscle strength measurement of knee flexion-extension, ankle dorsal-plantar flexion, and ankle inversion-eversion movements were evaluated with the manual muscle test (MMT) device. The timed up and go test (TUG), 5-repeat sit-and-stand test (5STS), and 10-m walk test (10MWT) were used to evaluate knee and ankle performance.

Results

A significant difference was found only for the five-repetitive sit-and-stand test among the classified groups considering the pes planus grade (p < 0.05). There was no significant difference between groups for other parameters (p > 0.05). In correlation analysis, there was only a relationship between the timed up and go test (TUG) with left foot dorsal flexor muscle strength and between 10-m walk test (10MWT) with right foot invertor muscle strength (r1 = − 0.288, r2 = − 0.288, p < 0.05).

Conclusions

The results of this study reveal that the duration of 5STS was significantly lower in the second degree pes planus group. TUG test score showed low negative correlation with left foot dorsal flexor muscle strength. In addition, the scores of 10MWT exhibited poor negative correlation with right foot invertor muscle strength. Regarding other parameters, no significant correlations were found.

The relationship between knee-ankle muscle strength and performance tests in young female adults with flexible pes planus

Background

A decrease in muscular activation of the knee and ankle is one of the primary reasons for pes planus. The muscle strength of the knee and ankle in patients with pes planus may affect the performance tests which consists of daily life activities. The aim of the study was to determine the relationship between knee and ankle muscle strength with performance tests in young female adults with flexible pes planus. In addition, we also aimed to observe whether the severity of pes planus affects the ankle muscle strength and performance test scores. We carried out a cross-sectional single-center study. The muscle strength measurement of knee flexion-extension, ankle dorsal-plantar flexion, and ankle inversion-eversion movements were evaluated with the manual muscle test (MMT) device. The timed up and go test (TUG), 5-repeat sit-and-stand test (5STS), and 10-m walk test (10MWT) were used to evaluate knee and ankle performance.

Results

A significant difference was found only for the five-repetitive sit-and-stand test among the classified groups considering the pes planus grade (p < 0.05). There was no significant difference between groups for other parameters (p > 0.05). In correlation analysis, there was only a relationship between the timed up and go test (TUG) with left foot dorsal flexor muscle strength and between 10-m walk test (10MWT) with right foot invertor muscle strength (r1 = − 0.288, r2 = − 0.288, p < 0.05).

Conclusions

The results of this study reveal that the duration of 5STS was significantly lower in the second degree pes planus group. TUG test score showed low negative correlation with left foot dorsal flexor muscle strength. In addition, the scores of 10MWT exhibited poor negative correlation with right foot invertor muscle strength. Regarding other parameters, no significant correlations were found.

Analysis of foot structure in young recreational female ballet dancers

Study aim: The human foot is an essential element of the locomotor system. It plays a key role in both the dynamics and the statics of the whole lower limb. The normal structure of the foot determines its mechanical function. During growth and formation of the foot structure, sport activity plays an important role.

The aim of this study was to analyse the structure of the foot in ballet dancers aged 6 to 14 years compared with a clinical reference peer group that did not do ballet.

Material and methods: The study involved 120 girls aged 6 to 14 years (mean age 9.6, sd. 2.4). Sixty of them formed the study group of ballet dancers, and the other 60 formed the reference group. To conduct the measurements, the computer podoscope CQ-ST produced by the CQ Elektronik System, connected to a portable computer, was used.

Results: A few differences were found between the foot structure in young female ballet dancers and their peers. A statistically significant difference was found in the hallux valgus α angle. The left foot of the examined ballet dancers was found to have a larger hallux valgus. A statistically significant correlation was found between the length of time of ballet training and the increase in the α angle values of the left foot and the right foot in the ballet group.

Conclusions: Ballet dancing in childhood may increase the risk of developing hallux valgus, with the tendency of worsening with training time.

Influence of badminton practice on calcaneal bone stiffness and plantar pressure

Objectives: The aim of this study was to analyze the plantar pressures and bone stiffness of the calcaneus in badminton players compare to healthy participants, as well as to detect possible asymmetries and chronic adaptations derived from the prolonged practice of badminton.Methods: Twenty-two badminton players (35.2 ± 13.6 years, 169.4 ± 8.2 cm, 67.6 ± 13.7 kg) and 30 healthy controls (32.2 ± 12.8 years, 170.7 ± 9.5 cm, 66.25 ± 14.84 kg) volunteered to participate in this investigation. A Footwork® Pro pressure platform was used to study plantar pressures and an Achilles® bone scanner was used to record the bone stiffness of the calcaneus. The variables analyzed were plantar surface, percentage of force per area (forefoot and hindfoot), distance between the center of pressure and the projection of the center of mass in standing, and calcaneal bone stiffness.Results: The values of bone stiffness of the calcaneus were higher in badminton players than control group in the dominant lower limb (Badminton = 114.32 ± 18.97 U.A. vs. Control = 102.07 ± 16.36 U.A.; p = 0.019) and non-dominant lower limb (Badminton = 115.12 ± 21.95 U.A. vs Control = 101.37 ± 15.72 U.A.; p = 0.014). Badminton players showed asymmetric values in mean pressure (dominant = 35.41 ± 6.05 Kpa vs. non-dominant = 39.21 ± 6.54 Kpa; p = 0.011) and distance among center of pressure of each foot and center of mass (dominant = 11.28 ± 1.65 cm vs. non-dominant = 10.48 ± 1.63 cm; p = 0.025).Conclusions: The calcaneal stiffness of the badminton players was higher than control group, which places badminton in the category of osteogenic sports. The badminton players showed an asymmetric pattern during the static balance, which may be an indicative of asymmetries derived from the continued practice of badminton.

Association of Foot Structure with the Strength of Muscles that Move the Ankle and Physical Performance

The human foot plays an important role in supporting body weight, maintaining postural balance, and absorbing ground reaction forces. Although many studies have indicated that a causal relationship exists between foot structure and alterations in lower extremity kinematics, there is little evidence regarding the possible association of foot structure with strength of muscles that move the ankle and physical performance. A total of 67 adult men with a mean age of 51.19 ± 8.82 years participated in this study. Foot structural parameters were assessed using a 3-dimensional foot scanner. Strength of muscles that move the ankle was measured with a dynamometer. Physical performance items, including agility, force, and proprioception, were also measured. We found that all the measured parameters of the length, width, girth, and height of the foot were positively correlated with the strength of plantarflexion, dorsiflexion, eversion, and inversion (r ranged from 0.26 to 0.57; p < .05). Moreover, all or part of the parameters of the length, width, and girth of the foot but not the height and angles of the foot were correlated significantly with vertical jump, stepping forward and backward, and stepping side to side (r ranged from 0.25 to 0.44; p < .05). These findings indicate a weak-to-moderate association between foot structure and the strength of muscles that move the ankle, as well as physical performance. We therefore suggest that a larger foot may have greater muscle strength of the ankle joint and better physical performance.

The Influence of the Improvement of Calf Strength on Barefoot Loading

The purpose of this study was to determine whether enhancement of calf muscular strength can produce influence on plantar pressure in barefoot running. Ten healthy male subjects (age:22±2.5 years, height: 1.76±0.4m, body mass: 65±2.5kg) participate this experiment enduring 8-week strength training adopting by calf raise movement on calf muscle. A medical ultrasonic instrument (Q6, China) was used to observe the variation of calf muscular morphology. A plantar pressure plate ( Novel Emed, Germany) was used to collect the variation of 8-region plantar pressure. After 8-week strength training, a significant increasing trend between pre-and post-strength training in subject`s pinnation angle (PA) of the gastrocnemius was found. Under strength training, there are some significant variations between pre-and post-plantar pressure. The start point of center of pressure (COP) gradually forward (middle foot 80%, forefoot 20%); the peak pressure of subject`s heel foot (HF) significantly lower; the maximal force in second-third metatarsal (M 2-3), medial foot (MF) and HF significantly decrease; the contact area in other toe (OT) significantly increase as well as MF and HF significantly decrease; the time-force integral in M2-3 and HF significantly lower and in MF significantly enhance. These results suggest, the enhancement of calf muscular strength may produce positively influence on beginning transitional process from shod running to barefoot running and is also worth to as a feasible way to recommend. However, the effects of strength straining on plantar pressure do not fully explore and still need to deeply explore own to existing limitations.

Gait Estimation from Anatomical Foot Parameters Measured by a Foot Feature Measurement System using a Deep Neural Network Model

An accurate and credible measurement of human gait is essential in multiple areas of medical science and rehabilitation. Yet, the methods currently available are not only arduous but also costly. Researchers who investigated the relationship between foot and gait parameters have found that the two parameters are closely interrelated and suggested that measuring foot characteristics can be an alternative to the strenuous quantification currently in use. This study aims to verify the potential of foot characteristics in predicting the actual gait temporo-spatial parameters and to develop a deep neural network (DNN) model that can estimate and quantify the gait temporo-spatial parameters from foot characteristics. The foot features in sitting, standing, and one-leg standing conditions of 42 subjects were used as the input data and gait temporo-spatial parameters at fast, normal, and slow speed were set as the output of the DNN regressor. With the prediction accuracy of 95% or higher, the feasibility of the developed model was verified. This study might be the first in attempting experimental verification of the foot features serving as predictors of individual gait. The DNN regressor will help researchers improve the data pool with less labor and expense when some limitations get properly overcome.

Association of arch height with ankle muscle strength and physical performance in adult men

Differences in arch height may have a certain impact on lower extremity muscle strength and physical performance. However, there is little evidence from investigation of the possible correlation of arch height with ankle muscle strength and physical performance measures. Sixty-seven participants took part in this study. Arch height index (AHI) was assessed and categorized using a 3-dimension foot scanner. Ankle muscle strength was measured employing a dynamometer. Physical performance measures including agility, force and proprioception were randomly tested. Compared to the medium AHI, the high AHI had lower plantarflexion and inversion peak torque. The high AHI also had lower peak torque per body weight value for plantarflexion and inversion at 120°/s (P = 0.026 and 0.006, respectively), and dorsiflexion at 30°/s (P = 0.042). No significant ankle muscle strength difference was observed between the low and medium AHI. Additionally, AHI was negatively correlated with eversion and inversion peak torque at 120°/s, and negatively associated with plantarflexion, eversion and inversion peak torque per body weight at both 30°/s and 120°/s (r ranged from -0.26 to -0.36, P values < 0.050). However, no significant relationship was found between arch height and physical performance measures. The results showed that high arches had lower ankle muscle strength while low arches exhibited greater ankle muscle strength. Arch height was negatively associated with ankle muscle strength but not related to physical performance. We suggest that the lower arch with greater ankle muscle strength may be an adaptation to weight support and shock absorption.

Toe flexor strength and foot arch height in children

PURPOSE

The aim of this study was to investigate the muscle strength and arch height of the foot in the standing position and the relations between these indices and physical performances involving the lower limbs in children.

METHODS

A total of 301 elementary school children (third grade: n = 158, age = 8.6 ± 0.5 yr; fifth grade: n = 143, age = 10.6 ± 0.5 yr; means ± SD) participated. The maximal isometric toe flexor strength (TFS) in the standing position was measured using a toe flexor dynamometer. Foot arch height was assessed as the distance between the navicular tuberosity of the foot and the floor in the standing position, and foot arch height relative to the foot length was represented by the foot arch index (FAI). For physical performance involving the lower limbs, 50-m sprint, standing broad jump, repeated side step, and rebound jump were measured.

RESULTS

There were no significant correlations between TFS and FAI and between relative TFS (relative TFS = TFS/body mass) and FAI. Relative TFS was significantly correlated with all physical performance tests. No significant correlations among FAI and physical performances were found, except for rebound jump ability in fifth graders. After multiple regression analyses adjusting for gender and body mass, TFS was the only significant correlating factor for all physical performances involving the lower limbs.

CONCLUSIONS

This study showed that TFS was associated with enhancement of some measures of lower limb physical performance in children. These results suggest that foot function should be evaluated with both the muscle strength and arch height of the foot in children.

Arch of the foot and postural balance in young judokas and peers

Twenty-nine male judocas and nontraining peers participated in this study. The arch of the foot (as Clarke's angular values) was measured under non-weight-bearing conditions in two-leg and one-leg stands. Postural balance was assessed by the Flamingo balance test. Judocas presented better static balance and higher arches of the foot. Significant differences in Clarke's angular values in a sitting and standing on two-leg position were found in both groups. After transition to a one-leg stand, the height of the arches of the foot in nontraining participants was still significantly decreased. Weight bearing did not affect Clarke's angular values in judokas. A correlation was found between the Flamingo test and Clarke's angle. Better balance was observed in adolescents with higher arch of the foot.

Foot and Ankle Deformity in Young Acrobatic and Artistic Gymnasts

Purpose. The aim of the paper was to determine the occurrence of feet and ankle deformities in trampoline and artistic gymnasts. Methods. Ten acrobatic gymnasts (trampolinists) and 10 artistic gymnasts aged 6-14 years were recruited. The calcaneal-tibial (rearfoot) angle was determined as the angle of the upper calcaneal tendon and the longitudinal heel axis while Clarke angles were determined by podoscopy. Results. The trampolinists showed significantly greater medial angulation (calcaneal valgus) than the group of gymnasts. Right and left foot Clark’s angles in both the trampoline and artistic gymnasts were above 55°. Conclusions. Trampolinists exhibit significantly more pronounced calcaneal valgus than artistic gymnasts. The prevalence of foot and ankle deformities in both populations should be addressed by coaches in the gymnastics training of young children.

Effects of Tai Chi versus Proprioception Exercise Program on Neuromuscular Function of the Ankle in Elderly People: A Randomized Controlled Trial

Background. Tai Chi is a traditional Chinese medicine exercise used for improving neuromuscular function. This study aimed to investigate the effects of Tai Chi versus proprioception exercise program on neuromuscular function of the ankle in elderly people. Methods. Sixty elderly subjects were randomly allocated into three groups of 20 subjects per group. For 16 consecutive weeks, subjects participated in Tai Chi, proprioception exercise, or no structured exercise. Primary outcome measures included joint position sense and muscle strength of ankle. Subjects completed a satisfaction questionnaire upon study completion in Tai Chi and proprioception groups. Results. (1) Both Tai Chi group and proprioception exercise group were significantly better than control group in joint position sense of ankle, and there were no significant differences in joint position sense of ankle between TC group and PE group. (2) There were no significant differences in muscle strength of ankle among groups. (3) Subjects expressed more satisfaction with Tai Chi than with proprioception exercise program. Conclusions. None of the outcome measures on neuromuscular function at the ankle showed significant change posttraining in the two structured exercise groups. However, the subjects expressed more interest in and satisfaction with Tai Chi than proprioception exercise.

Ankle impingement syndromes: a review of etiology and related implications

Ankle injuries are common occurrences in athletics involving and requiring extreme ranges of motion. Ankle sprains specifically occur with a 1 in 10,000 person rate in active individuals each day. If trauma is repetitive, the ankle structures have potential to experience secondary injury and dysfunction. Included in this category of dysfunction are both anterior and posterior ankle impingement syndromes where disruption of the bony structures, joint capsule, ligaments, and tendons typically occurs. Ankle impingement is described as ankle pain that occurs during athletic activity, with recurrent, extreme dorsiflexion or plantar flexion with the joint under a load. Ankle impingements can be classified according to what structures become involved both anteriorly and posteriorly. Osseous impingement, soft tissue impingement, impingement of the distal fascicle of anterior inferior tibiofibular ligament, and meniscoid lesions are all documented causes of ankle impingement. These changes tend to be brought about and exacerbated by extreme ranges of motion. Understanding various impingement types will better enable the clinician to prevent, identify, treat, and rehabilitate affected ankles. Acknowledging activities that predispose to ankle impingement syndrome will enhance prevention and recovery processes. Description of ankle impingement etiology and pathology is the objective of the current review.

Effect of ischemic preconditioning in skeletal muscle measured by functional magnetic resonance imaging and spectroscopy: a randomized crossover trial

BACKGROUND

Nuclear magnetic resonance (NMR) imaging and spectroscopy have been applied to assess skeletal muscle oxidative metabolism. Therefore, in-vivo NMR may enable the characterization of ischemia-reperfusion injury. The goal of this study was to evaluate whether NMR could detect the effects of ischemic preconditioning (IPC) in healthy subjects.

METHODS

Twenty-three participants were included in two randomized crossover protocols in which the effects of IPC were measured by NMR and muscle force assessments. Leg ischemia was administered for 20 minutes with or without a subsequent impaired reperfusion for 5 minutes (stenosis model). IPC was administered 4 or 48 hours prior to ischemia. Changes in 31phosphate NMR spectroscopy and blood oxygen level-dependent (BOLD) signals were recorded. 3-Tesla NMR data were compared to those obtained for isometric muscular strength.

RESULTS

The phosphocreatine (PCr) signal decreased robustly during ischemia and recovered rapidly during reperfusion. In contrast to PCr, the recovery of muscular strength was slow. During post-ischemic stenosis, PCr increased only slightly. The BOLD signal intensity decreased during ischemia, ischemic exercise and post-ischemic stenosis but increased during hyperemic reperfusion. IPC 4 hours prior to ischemia significantly increased the maximal PCr reperfusion signal and mitigated the peak BOLD signal during reperfusion.

CONCLUSIONS

Ischemic preconditioning positively influenced muscle metabolism during reperfusion; this resulted in an increase in PCr production and higher oxygen consumption, thereby mitigating the peak BOLD signal. In addition, an impairment of energy replenishment during the low-flow reperfusion was detected in this model. Thus, functional NMR is capable of characterizing changes in reperfusion and in therapeutic interventions in vivo.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00883467.

Relationship between explosive muscle strength and medial longitudinal arch of the foot

BACKGROUND

There has been a suggested link between muscle strength and arch type of the foot. However, a distinct cause and effect dependence has yet to be established. The purpose of this study was to compare the outcomes from selected explosive strength tests with different arch heights.

MATERIAL AND METHODS

The medial longitudinal arch (MLA) was measured using a Clarke's angle method. Five hundred seventy-four subjects (n = 574) participated in this study and were divided into three arch height groups and three muscle strength groups, respectively. To evaluate the association between longitudinal arch of the foot with the explosive power of lower limb muscles, Chi-square (χ²) test was used.

RESULTS

Arch heights were not significantly related to explosive muscle strength.

CONCLUSIONS

Arch measurement was ineffective in accounting for the observed variability in the explosive strength among young adults.

CLINICAL RELEVANCE

This data may be useful in evaluating patients with painful flat feet and any strength deficits they may have.

Foot and ankle injuries in elite female gymnasts

BACKGROUND

Gymnastics is a competitive and popular sport that is started at an early age, and elite female gymnasts reach their prime in mid-teenage years. The level of intensity of practice and competition, the number of events, and the degree of difficulty of the maneuvers make gymnastics one of the most injury-producing sports.

METHODS

Over a 3-year period, 14 elite, female gymnasts were seen in one foot and ankle center. The mean age was 17 (range 14 to 21) years. All gymnasts sustained acute or sub-acute injuries to the foot or ankle requiring surgery. The mechanism of injury, the type of injury, operative repair, and followup were recorded.

RESULTS

There were five Lisfranc fracture-dislocations, and five talocalcaneal, two multiple metatarsal, one medial malleolar, one phalangeal, and one sesamoid fracture. All injuries had operative repair. One gymnast with a Lisfranc injury was able to return to full competition; all others with a Lisfranc injury retired from gymnastics, were lost to followup, or graduated from college. One gymnast with a talar osteochondral injury was not able to return to competition but all other injured gymnasts were able to return to gymnastics at the same level or higher.

CONCLUSION

Elite female gymnasts can sustain significant injury to the foot and ankle region. In our study, Lisfranc injuries were most likely career-ending.