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Chronic ankle instability (CAI) causes impairment in proprioception, such as ankle joint position sense and plantar cutaneous sensation. Although plantar vibration stimulation may be effective as a means of enhancing proprioception, its efficacy remains ambiguous. This study aimed to clarify the immediate effects of plantar vibration stimulation on healthy athletes and athletes with CAI. Eight healthy and eight CAI athletes participated in this study, and their joint position sense and cutaneous sensation were evaluated before and after the intervention of plantar vibration stimulation or non-intervention, designed as a cross-over study. There were no significant differences between the healthy group and the CAI group in both joint position and plantar cutaneous sensation. Also, there were no statistically significant changes in either group before or after the intervention. One possible explanation for the absence of differences between the healthy and CAI groups could be attributed to a high Foot and Ankle Ability Measure score. Neither group exhibited any changes in joint position or plantar cutaneous sensation following the vibration intervention. The frequency and amplitude of the vibration stimulation affecting proprioceptors may be different, and the joint position and plantar cutaneous sensation of CAI groups may be comparable with those of healthy participants. [ABSTRACT FROM AUTHOR]

Ankle brace is commonly used to treat and prevent ankle sprain. Its main aim is to restrict supination of the ankle. However, some braces restrict ankle dorsiflexion and plantar flexion. In addition, loosening and loss of restriction after exercise have also been reported. The purpose of this study was to reveal if thin-type ankle brace for ankle sprain restricts ankle dorsiflexion and plantar flexion and its effect of exercise. Five male adults (average age of 30.8 ± 5.2 years) were included in the study. Dorsiflexion and plantar flexion of subjects' right ankle was measured before and after wearing the brace, and before and after exercises. Exercises consisted of performing 20 times of calf raise, full squat, maximum vertical jump, and 5-minute running on a treadmill. Measurement was performed thrice, and their average was statistically analyzed between with and without the brace, and before and after each exercise. The results showed that there was no significant difference between all measured angles of with and without the brace and before and after each exercise. Thin-type ankle brace for ankle sprain have been reported to restrict supination. Considering our results, this brace does not restrict ankle dorsiflexion and plantar flexion. [ABSTRACT FROM AUTHOR]

Abstract Purpose The flexor digitorum longus and posterior tibial tendon as well as the perforating veins are located along the distal posteromedial tibial border. Adipose tissue may surround these structures and possibly play a role in reducing mechanical stress. This study aimed to examine the adipose tissue along the posteromedial tibial border via magnetic resonance imaging (MRI), ultrasound, and gross anatomical examination. Methods The lower legs of 11 healthy individuals were examined every 3 cm from the medial malleolus using MRI and ultrasound. The fat fraction was calculated using fat fraction images. In addition, the gross anatomy of the flexor digitorum longus origin and adipose tissue along the posteromedial tibial border was examined in seven fresh cadavers. The fat fraction was compared at different heights along the posteromedial tibial border and in Kager’s fat pads; we also compared the height of the flexor digitorum longus origin and adipose tissue. Results In vivo, the adipose tissue was identified along the entire posteromedial tibial border using MRI and ultrasound. There was no significant difference in fat fraction between Kager’s fat pads and the adipose tissue along the posteromedial tibial border, except at the 6 cm mark. All seven cadavers presented adipose tissue along the posteromedial tibial border, significantly more distal than the flexor digitorum longus origin. Conclusion The adipose tissue was identified along the posteromedial tibial border via MRI, ultrasound, and gross anatomical examination; thus, this tissue may play a role in reducing friction and compressive stress in tendons.

Background: Sports injuries often occur during landing, necessitating postural stability for injury prevention. Electrical stimulation of the plantar foot induces activities of the intrinsic foot muscles and improves somatosensory and postural stability during landing. However, this effect remains unclear. Therefore, the aim of this study was to investigate the immediate effects of electrical stimulation on the activities of the intrinsic foot muscles, plantar somatosensory system, and postural stability during landing., Methods: Twenty-two college athletes were divided into an electrical stimulation group and a control group. Electrical stimulation was applied to the plantar foot using a commercial device. The toe function and plantar tactile sensations were evaluated. The activities of the intrinsic muscles and the parameters of the ground reaction force were measured and calculated. We compared pre- and postintervention outcomes., Results: In the electrical stimulation group, two subjects showed improvement in toe function, and plantar tactile sensation improved significantly postintervention. The control group exhibited no significant change in plantar tactile sensation. A significant interaction was observed in anteroposterior postural stability during landing, notably improving in the electrical stimulation group., Conclusions: Electrical stimulation of the plantar foot immediately improved toe function, plantar tactile sensation, and postural stability during landing. Such stimulation would be beneficial in preventing sports injuries.

Background: The purpose of this study was to clarify the differences in the movement of the superficial microchambers and deep macrochambers of the heel fat pad during loading and unloading movements, and to clarify the influence of height and weight on this movement., Methods: The subjects were 21 healthy adults. The right foot was placed on an evaluation instrument stand made of polymethylpentene (PMP) resin plate, and the left foot was placed on a scale stand used to adjust the amount of load. When measuring, the heel fat pad is divided into the superficial microchamber layer and the deep macrochamber layer, and the thickness due to loading from 0% to 100% of the body weight and unloading from 100% to 0% is measured. Measurement was performed every 20% using an ultrasound imaging device. We also examined the rate of change in the thickness of the superficial and deep layers of the heel fat pad when applying 100% load (end load) from 0% load (unload)., Results: No changes were observed in the superficial layer of the heel fat pad during unloading, but significant changes were observed in the deeper layers. Additionally, the thickness of the microchamber and macrochamber layers tended to increase under each loading condition as the height and weight increased. On the other hand, the rate of change in the thickness of the macrochamber layer tended to decrease., Conclusion: The microchamber layer and the macrochamber layer of the heel fat pad may have different functions. As height and weight increase, the thickness of the microchamber and macrochamber layers may increase, and the rate of change in the thickness of the macrochamber layer appears to decrease. Although the thickness increases as the load increases, we found that the related elasticity decreases., Level of Evidence: Level Ⅳ, cross-sectional survey study., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online., (© The Author(s) 2024.)

Toe flexor strength is generated primarily by the flexor hallucis longus (FHL) of the extrinsic foot muscles (EFMs) and the plantar intrinsic foot muscles (PIFMs) of the great toe. Toe flexion methods can be broadly classified into toe grip (TG) and toe push-down (TP). Additionally, TP's interphalangeal joint (IPJ) position may influence the FHL and PIFMs activity ratios. This study aimed to elucidate the differences in the muscle activity and muscle activity ratios of the FHL and AbdH during TG, TP with IPJ flexion (TPIF), and TP with IPJ extension (TPIE). Surface electromyography and a custom-made instrument were used to measure the FHL and AbdH muscle activity during TG, TPIF, and TPIE of the great toe in 28 healthy men. The muscle activity and AbdH/FHL muscle activity ratio in the three conditions were statistically compared. The FHL activity was significantly higher during TG and TPIF than during TPIE. The AbdH muscle activity was significantly higher during TPIF and TPIE than that during TG. The AbdH/FHL muscle activity ratio was significantly higher for TPIE, TPIF, and TG in that order. This study showed that the FHL and AbdH muscle activity differed depending on the TG and TP of the great toe, and that the AbdH/FHL muscle activity ratio was different in the IPJ position. These results suggest that selecting a toe flexion method according to the target muscle when measuring and training the great toe flexor strength is important., Competing Interests: Declaration of Competing Interest There are no conflicts of interest regarding this study., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: This study aimed to determine the risk factors of hallux valgus angle among preprofessional adolescent dancesport athletes., Methods: A total of 275 athletes, (73 males and 202 females) aged between the ages of 11 and 18 years, participated in this study. A cross-sectional questionnaire was used to survey their demographic characteristics (sex and age), training information (starting age, weekly training time, and athletic career [number of years of training at this specific dancesport school]), and measured their height and weight. The hallux valgus angle was measured based on foot photographs. The chi-square test was used to compare the difference with prevalence of hallux valgus between male and female athletes. A normal distribution test was performed, and based on the test results, unpaired t-test and multiple logistic regression were conducted to identify training factors for the hallux valgus in this cohort., Results: Chi-square test showed higher prevalence of hallux valgus in female elite adolescent dancesport athletes than males. The t-test results did not show any significant differences between the hallux valgus group and non-hallux valgus groups with start age, athletic career, and weekly training time. Multiple logistic regression analysis with hallux valgus as the dependent variable revealed that the female sex was a strong predictor of a higher prevalence of hallux valgus (odds ratio [OR]: 3.954, 95% confidence interval 95% CI: 2.193-7.131, and p < 0.001). Weekly training time was also entered into the multiple logistic regression model (OR: 1.033, 95% CI: 1.001-1.067, and p = 0.041)., Conclusions: Our findings revealed that the prevalence of hallux valgus in adolescent dancesport athletes was higher in females than in males. Longer weekly training time was also a risk factor for hallux valgus. Training factors should be considered in preventive programs for elite adolescent dancesport athletes, and special attention should be paid to female athletes., (© 2024 The Author(s). Journal of Foot and Ankle Research published by John Wiley & Sons Australia, Ltd on behalf of Australian Podiatry Association and The Royal College of Podiatry.)

Activities on sandy soil are known to contribute to improved leg strength and balance. Lifesavers (LSs) have shown that sandy soil activity promotes intrinsic foot muscle development and improves balance. LS improves leg strength and balance through activities on sandy soil. However, the effect of foot muscle development on the actual muscle activity of LS remains unclear. We aimed to evaluate the effect of foot muscle development on muscle activity in lifeguards on a sandy beach compared with the corresponding in healthy participants. Fifteen LSs and 15 healthy adults underwent a Y-balance test to assess dynamic balance and surface electromyography to measure muscle activity. The LSs exhibited a significantly higher percentage of maximum voluntary contraction values in the tibialis anterior muscle in all directions than the healthy adults. The LSs showed increased peroneus longus and abductor hallucis muscle activity in the posterolateral and posteromedial directions, suggesting their involvement in contralateral postural control during dynamic balance. These findings suggest that engaging in barefoot activities on sandy soil enhances foot muscle activity and improves dynamic balance in LSs., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Ethics Review Committee of Waseda University issued approval 2023-370. Written informed consent was obtained from the participants, who were informed in advance. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Suzuki et al.)

Balance is important in lifesaving competitions. We aimed to investigate the relationship between dynamic balance and physical characteristics and functions in elite lifesavers by measuring the foot muscle cross-sectional area, ankle joint muscle strength, toe grasp strength, plantar superficial sensation, and dynamic balance (Y-balance test). In this observational study, we measured the foot muscle cross-sectional area, ankle dorsiflexion, plantar flexion, external flexion, isometric muscle strength, toe grasp strength, and superficial foot sensation of 15 adult lifesavers (12 males). The results show that toe grasp strength and ankle plantar flexion isometric muscle strength are particularly important for the dynamic balance of elite lifesavers working on sandy surfaces. Sand training improves intrinsic muscle strength and dynamic balance function. However, high training intensity may reduce plantar surface sensation; this needs to be verified through sand training interventions in the future.

Background: This study aimed to investigate age-related changes in the heel fat pad's microchamber and macrochamber layers, particularly focusing on load-induced alterations. Understanding these changes is crucial for elucidating age-related differences in foot mechanics and their potential implications for mobility and comfort., Methods: Fifty-five healthy individuals were divided into three age groups: young adults (≤29 years), middle-aged adults (30-44 years), and elderly individuals (≥45 years). Ultrasonic imaging was utilized to measure the thickness of the heel fat pad's microchamber and macrochamber layers under varying load conditions. Thickness, percentage changes, and ratios of load-induced thickness changes were calculated to assess age-related differences., Findings: Under no-load conditions, both microchamber and macrochamber layers of the heel fat pad were significantly thicker in middle-aged and elderly individuals than in young adults. When load was applied middle-aged and elderly participants exhibited smaller changes in the macrochamber layer and larger changes in the microchamber layer compared to young adults., Interpretation: Our findings suggest that age influences the structural characteristics and response of the heel fat pad to mechanical loading. Thicker heel fat pad layers in middle-aged and elderly individuals under no-load conditions may reflect age-related changes in fat distribution or composition. Moreover, differences in load-induced thickness changes indicate altered mechanical properties with age, potentially affecting shock absorption and overall foot function. Understanding these age-related variations can help develop interventions aimed at preserving foot health and mobility across the lifespan., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: The menstrual cycle is an important indicator of health in female athletes. Female elite adolescent dancers are expected to control their weight while also training intensely, which can lead to menstrual disorders. This study aimed to investigate the relationship between body composition and menstrual status in female elite adolescent dancers. Methods : In total, 131 female elite adolescent dancers (age: 15.9 ± 1.5 years) were enrolled in this study. We measured the height, weight, and body fat percentage (BFP) for each participant and calculated their body mass index (BMI). We gathered information on individual menstruation patterns and the participants' menstrual cycles over the previous year using recall methods. We then compared the differences between dancers with menstrual cycle disorders and those without. Primary amenorrhea was defined as menarche occurring after the age of 15, while secondary amenorrhe was defined as experiencing fewer than 5 or no menstrual periods for at least 3 of the previous 12 months. We conducted a reliability test using the same questionnaire 2 weeks later. Statistical significance was defined as P  < .05, and we calculated the effect sizes (d) and 95% confidence intervals (95% CI). Results : The average BMI and BFP were 22.6 ± 3.0% and 19.4 ± 2.2 kg/m 2 , respectively. Low BFP and low BMI were observed in 51 (38.6%) and 47 (35.6%) participants, respectively. Primary amenorrhea in 3 participants (2.3%) and 29 (22.1%) reported experiencing secondary amenorrhea; they had lower BFP than the dancers who did not experience amenorrhea ( P  = .041, 95% CI, -2.51 to -0.05). Conclusion : Female elite adolescent dancers in China may have lower BFP and menstrual problems. Given that lower BFP may contribute to the occurrence of menstruation disorders, it is essential to pay an attention to both BFP and the menstruation status in female elite adolescent dancers., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: This study aimed to investigate the thickness changes of the heel fat pad and the plantar fascia associated with loading and unloading in healthy individuals and patients with heel pain and reveal the differences between them., Methods: The study included adult male participants with (n = 9) and without (n = 26) heel pain. The participants placed their right foot on an evaluation apparatus with a polymethylpentene resin board (PMP), while their left foot was positioned on a weighing scale used to adjust the loading weight. The heel fat pad was differentiated into superficial Microchamber and deep Macrochamber layers. These layers and plantar fascia thickness were measured using an ultrasonographic imaging device at loading phase ranging from 0% to 100% of their body weight and unloading phase from 100% to 0%. Additionally, the study examined the thickness change ratios of the superficial and deep heel fat pad layers when the load increased from 0% (unload) to 100% (full load)., Results: In healthy individuals and patients with heel pain, no significant thickness changes were observed in the Microchamber layer of the heel fat pad or the plantar fascia during loading and unloading evaluations. However, significant thickness changes were observed in the Macrochamber layer of the heel fat pad, and the pattern of change differed between the loading and unloading phases. Additionally, patients with heel pain showed differences in the thickness change and thickness change ratios of the microchamber and macrochamber layers of the heel fat pad during both loading and unloading phases. The thickness of the plantar fascia did not show significant differences between both groups., Conclusion: Compared with healthy individuals, in our relatively small study, patients with heel pain had greater deep fat pad compression in loading and less recovery after load removal. This finding suggests that these patients have different intrinsic fat pad function and related morphology than those without heel pain., Level of Evidence: Level III, retrospective cohort study., Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. Disclosure forms for all authors are available online., (© The Author(s) 2024.)

Prevalence of impaired foot function among baseball players with and without a disabled throwing shoulder/elbow was investigated. The study included 138 male players. Players who had previously complained of shoulder/elbow pain during throwing motion were defined as the players with a history, and those who experienced shoulder/elbow pain during the examination were defined as having the injury. Foot function was evaluated by foot "rock paper scissors" movements and floating toes. Their prevalence was assessed and the relationships between players with and without the injuries were statistically analyzed. The prevalence of players with a history and injury was 27% and 7%, respectively. The prevalence of impaired foot function on the non-throwing side among players with injury was significantly higher than those without (60% vs. 28%, P < 0.001) and higher tendency on the throwing side than those without (60% vs. 32%). Regarding floating toes, players with a relevant history showed a significantly higher prevalence on the throwing side than those without (49% vs 28%, P < 0.001) and higher tendency on the non-throwing side than those without (49% vs 32%). Players with disabled throwing shoulder/elbow have a significantly higher prevalence of impaired foot function and floating toes than players without it., (© 2024. The Author(s).)

Background: Local high-frequency percussive (HFP) massage has recently found widespread application in physical therapy. Although HFP massage reportedly improves range of motion (ROM), the mechanism underlying its action has not yet been proven. This study aimed to clarify whether a 5-minute percussive massage regimen affects muscular or connective tissues, such as the deep fascia and deep intermuscular fascia and the change in joint ROM., Method: The study sample was calculated using G*Power analysis program, and this study enrolled 15 healthy men who underwent 5-minute HFP massage to the medial gastrocnemius muscle. Shear-wave elastography was used to measure tissue stiffness in the deep fascia, muscle, and deep intermuscular fascia through shear-wave velocity as well as the ROM of the volunteers' ankle joint dorsiflexion before and after the HFP massage. A value of P < .05 was used to declare statistical significance, and post hoc was used to calculate the effect size using G*Power., Results: Shear-wave velocity revealed a significant change in the deep fascia (P = .003; shear-wave velocity: -0.7 m/s) and significant increase in ROM of ankle dorsiflexion (P = .002; increase in ROM: 3.0°) after 5 minutes of HFP massage. However, the muscle and deep intermuscular fascia did not exhibit any significant changes., Conclusions: HFP massage for 5 minutes modified the stiffness of the deep fascia and concurrently improved the ankle joint-dorsiflexion ROM. This method can be used as an intervention to decrease stiffness of the deep fascia and increase the ROM efficiently.

Background: Floating toes are a condition and deformity in which some of the toes are afloat. Many functional impairments in floating toes have been previously studied lately and several factors related to floating toes have also been reported. However, no reports have considered the relationship between lifestyle and floating toes among children. The purpose of this study was to reveal the prevalence of floating toes among school children and reveal its relationship with lifestyle., Methods: In total, 138 young male baseball players were recruited. Lifestyle was evaluated by using a questionnaire and chosen whether the main lifestyle was Japanese or Western, if the bedding was futons or beds, and if the toilet was Japanese style (a squat toilet) or Western style. Floating toes were defined as toes that were not in contact with the mat. Ankle dorsiflexion in the knee-flexed and knee-extended positions was measured in a weight-bearing position. The relationship between the floating toes and lifestyles, and the comparison of ankle dorsiflexion range of motion between the lifestyles were statistically analyzed., Results: Players living in a Western style showed a significantly higher prevalence of floating toes on both feet compared with the players living in a Japanese style (throwing side; 39% vs. 19%, p = 0.04, and non-throwing side; 43% vs. 19%, p = 0.01). Players living in a Western style with beds showed a significantly smaller range of motion on both sides of ankle dorsiflexion in the knee-flexed position compared with those who were not (throwing side; 37.2 ± 5.7° vs. 39.0 ± 6.6°, p = 0.04, and non-throwing side; 36.8 ± 5.8° vs. 38.6 ± 6.1°, p = 0.04)., Conclusion: Children mainly living in a Western lifestyle showed a significantly higher prevalence of floating toes on both feet compared to those mainly living in a Japanese lifestyle. The prevalence of floating toes may be related to lifestyles among children., Trial Registration: The study was approved by the institutional review board of the Waseda University Graduate School of Sport Sciences (IRB number 2021-185)., (© 2023. The Author(s).)

[Purpose] To measure the sub-sesamoid soft tissue thickness change from non-loading to self-weight loading conditions. [Participants and Methods] The study included 17 female participants for the study. A questionnaire was used to collect the demographic data and participant anamnesis, such as the presence of foot injuries and diabetes. The measured height and weight were used to calculate the body mass index. Participants were required to stand on an evaluation device from non-loading to 100% loading conditions to measure the sub-sesamoid soft tissue thickness. [Results] Significant differences were observed between the tibial and fibular sub-sesamoid soft tissue thicknesses under non-loading and all loading conditions. Significant soft tissue thinning was observed with a change from non-loading to 25% loading condition. However, no significant differences in the rate of change were observed between the tibial and fibular sub-sesamoid soft tissue thicknesses at 100% loading. [Conclusion] The sub-fibular sesamoid soft tissue was thicker than the sub-tibial sesamoid soft tissue in all loading conditions. The sub-sesamoid soft tissue thickness change was larger during initial loading stage than during the late loading stage, which may be normal in healthy females in their 20s., Competing Interests: None., (2023©by the Society of Physical Therapy Science. Published by IPEC Inc.)

This study aimed to compare the foot muscle morphology and foot posture between healthy adults and lifesavers in sandy beach sports. The participants included 15 lifesaver athletes and 15 healthy adults. Using a non-contact three-dimensional foot measurement device, the foot length, width, and arch height of the right foot were measured while standing and sitting without back support, and the transverse arch length ratio and arch height index were subsequently calculated. Muscle cross-sectional area was measured using an ultrasound imaging device. Muscle cross-sectional areas, arch height, foot width, arch height index, and transverse arch length ratio were larger in the lifesaver than in the healthy adult group. Lifesavers had higher arches and more developed intrinsic and extrinsic muscles than healthy adults. Performing physical activity while barefoot on sandy beaches may effectively develop the foot intrinsic and extrinsic muscles and raise the arch.

Previously, we developed an instrument to evaluate the heel fat pad (HFP) two-layer structure, under varying loading conditions, with ultrasonography from the plantar surface through a polymethylpentene resin plate; the measured values were equivalent to those obtained without this plate. The study described here aimed to determine the intra- and inter-examiner reliabilities of the HFP thickness measurements and the agreement between long- and short-axis measured values using this instrument. Two examiners successively recorded the HFPs of 40 healthy adults twice under the no loading and loading conditions on the long- and short-axis scans. The HFPs were classified into two layers, and their thicknesses were measured. Short-term intra- and inter-examiner reliabilities were determined using the intraclass correlation coefficients. Measurements were repeated 1 mo later to determine the long-term intra-examiner reliability. The agreement between the measured long- and short-axis values was investigated by calculating the minimal detectable changes. The determined short- and long-term intra-examiner reliabilities ranged from 0.750 to 0.999 and from 0.765 to 0.952, respectively. Inter-examiner reliability ranged from 0.765 to 0.997. Differences may occur between the values measured at different axes. The measurements using this evaluation instrument were reliable, and it is best to unify the measurement axis for quantitative research., Competing Interests: Conflict of interest disclosure The authors declare no conflicts of interest., (Copyright © 2022 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Background: Female soccer players are often diagnosed with medial shin pain, which includes tibial stress fracture, medial tibial stress syndrome, and chronic exertional compartment syndrome. As the possibility of varied sites of pain affecting sports activities has not been fully researched, an urgent discussion and evidence is required. This study investigates the prevalence and effect of sites of pain on the sports activities of female soccer players with medial shin pain., Methods: A questionnaire survey was conducted for 196 female soccer players with medial shin pain to assess symptom duration, the effect of practice and performance, and sites of pain. The players were classified into three conditions (tibial stress fracture, medial tibial stress syndrome, or medial shin pain with neurological symptoms) and compared based on sites of pain., Results: We observed that medial tibial stress syndrome had a lower impact on performance compared to that of tibial stress fracture and medial shin pain with neurological symptoms. While participants with tibial stress fracture had to suspend practice sessions more frequently, the difference in symptom duration between the classified groups was not statistically significant. The effect of sites of pain on sports activities was not significantly different in participants with medial tibial stress syndrome., Conclusions: Medial shin pain should be evaluated carefully to differentiate between medial tibial stress syndrome and medial shin pain with neurological symptoms. Restriction of sports activities may help improve the patient's condition early, regardless of the presentation.

Background: Adolescent DanceSport athletes who regularly dance in high heels have a higher possibility of developing hallux valgus deformity and foot pain. We believe that the occurrence of foot disorders may change the loading on their feet, which thus affects the athletic performance of those adolescents., Methods: A total of 63 adolescent DanceSport athletes (16 boys, 47 girls) were included. The plantar pain in the first metatarsophalangeal (1st MTP) joint was evaluated using a questionnaire, and the hallux valgus angle was evaluated using digital photographs (HVAp). The loading values of the plantar pressure while performing relève on demi-pointe were measured using sensor sheets. The participating boys and girls were analyzed separately., Results: The results showed that female adolescent DanceSport athletes with the 1st MTP joint plantar pain showed a decrease in the loading distribution and plantar pressure percentage on the hallux and an increased loading distribution and pressure distribution of the metatarsal head as the HVAp increased., Conclusion: Among adolescent DanceSport athletes with plantar pain in the 1st MTP joint and a large HVAp, the loading manner of the foot may have changed, which may be associated with a decrease in the toe function and performance.

To evaluate the two-layer structure of the heel fat pad (HFP) from non-weight-bearing to full-weight-bearing conditions, we developed an instrument that assesses these changes from the sole through a polymethylpentene resin plate (PMP) with ultrasonography. For actual use, we investigated the influence on measured values and ultrasonogram appearance by interposing the PMP. Additionally, as the PMP may be bent under weight-bearing conditions, its influence on the measured values was investigated. First, two examiners measured the distances inside the phantom with and without a PMP. Second, ultrasonograms were obtained from 40 healthy adults with and without a PMP, and the thicknesses of the whole layer and the two layers of the HFP were measured using the same ultrasonogram. For each experiment, reproducibility was investigated. Third, the distances inside the phantom were measured and compared through the bent PMP, which models the weight-bearing condition, and the flat PMP. The reproducibility of the measurements was equivalent with and without the PMP interposed. Potential bias in measured values arising from deformation of PMP under weight-bearing conditions was not detected. Overall, the PMP's interposition and the bending of the PMP might not influence the measured values and reproducibility of the measurements., Competing Interests: Conflict of interest disclosure All authors declare they have no conflicts of interest., (Copyright © 2021 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

Excessive foot pronation during static standing, walking and running has been reported as a contributing factor for the development of medial tibial stress syndrome (MTSS). The motion of foot pronation consists of hindfoot and forefoot motion. However, no previous studies have investigated forefoot and hindfoot kinematics during walking and running in subjects with MTSS. The current study sought to compare hindfoot and forefoot kinematics between subjects with and without MTSS while walking and running. Eleven subjects with MTSS and 11 healthy controls (each group containing 10 males and one female) participated in the current study. Segment angles of the hindfoot and forefoot during walking and running barefoot on a treadmill were recorded using three-dimensional kinematic analysis. An independent t-test was used to compare kinematic data between groups. Subjects with MTSS exhibited significantly greater hindfoot eversion and abduction (p < 0.05) during walking and running than subjects without MTSS, significantly greater forefoot eversion and abduction (p < 0.05) during walking, and significantly greater forefoot abduction during running (p < 0.05). Hindfoot and forefoot kinematics during walking and running were significantly different between subjects with and without MTSS. For prevention and rehabilitation of MTSS, it may be important to focus on not only hindfoot but also forefoot kinematics during both running and walking. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

The objective of the current study was to investigate the kinematic relationships between the rearfoot and hip/knee joint during walking and single-leg landing. Kinematics of the rearfoot relative to the shank, knee and hip joints during walking and single-leg landing were analyzed in 22 healthy university students. Kinematic relationships between two types of angular data were assessed by zero-lag cross-correlation coefficients and coupling angles, and were compared between joints and between tasks. During walking, rearfoot eversion/inversion and external/internal rotation were strongly correlated with hip adduction/abduction (R=0.69 and R=0.84), whereas correlations with knee kinematics were not strong (R≤0.51) and varied between subjects. The correlations with hip adduction/abduction were stronger than those with knee kinematics (P<0.001). Most coefficients during single-leg landing were strong (R≥0.70), and greater than those during walking (P<0.001). Coupling angles indicated that hip motion relative to rearfoot motion was greater than knee motion relative to rearfoot motion during both tasks (P<0.001). Interventions to control rearfoot kinematics may affect hip kinematics during dynamic tasks. The coupling motion between the rearfoot and hip/knee joints, especially in the knee, should be considered individually., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Purpose: The purpose of the present study was to evaluate lower limb kinematics and muscular activities during walking, side-turning while walking, and side-cutting movement in athletes with chronic ankle instability and compare the results to those of athletes without chronic ankle instability., Methods: Lower limb kinematics and muscular activities were evaluated in 10 athletes with chronic ankle instability and 10 healthy control athletes using a three-dimensional motion analysis system and surface electromyography during the 200-ms pre-initial contact (IC) and stance phases while walking, side-turning while walking, and side-cutting., Results: During walking or side-turning while walking, there were no significant differences in kinematics or muscle activities between the subjects with and without chronic ankle instability. For the side-cutting task, however, ankle inversion angles during the 200-ms pre-IC and late stance phases [effect sizes (ESs) = 0.95-1.43], the hip flexion angle (ESs = 0.94-0.96) and muscular activities of the gastrocnemius medialis (ESs = 1.04-1.73) during the early stance phase were significantly greater in the athletes with chronic ankle instability than in the healthy control athletes., Conclusions: Alterations of kinematics in athletes with chronic ankle instability were found not only at the ankle but also at hip joints during the side-cutting movement. These alterations were not detected during walking or side-turning while walking. The findings of the present study indicate that clinicians should take into account the motion of the hip joint during the side-cutting movement in persons with chronic ankle instability., Level of Evidence: III.