• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.79-85
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• 2017

As the number of patients suffering from Pes Planus increases, research on a correctional insole that can cope with them is increasingly required. Therefore, the design of an insole for Pes Planus Correction was studied using the superelastic effect, which is one of the characteristics of the shape memory alloy in this paper. To design an effective insole, the effect of the contact pressure induced by the insole on the plantar fascia, which is the most important muscle in the foot structure, was evaluated. Three parameters (thickness, max. height and asymmetric ratio) were set as the main design factors of the insole, and the maximum contact pressure appearing on the plantar fascia was calculated by finite element analysis and analyzed using the Taguchi method. As a result of the analysis, it was confirmed that the contact pressure was influenced in the order of max. height, thickness, and asymmetric ratio. In addition, the contact pressure was converted to a feeling pressure that could be felt by a person, and then a safety correction range was established that would not cause any irritation to the plantar fascias, even though the correction effect could be expected. This indicates the best design for the safety correction range. The design method considering the important factors established through this study can form the basis for designing a personalized correctional insole in the future.

• Journal of Korean Physical Therapy Science
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• v.26 no.1
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• pp.9-14
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• 2019

Background: Pes planus, or flat foot, causes lower limb malalignment and foot pain during walking or exercise. Therefore, a highly reliable evaluation method to accurately diagnose flat feet is necessary. This study investigated the intra-and inter-rater reliability of the navicular drop test in different postures. Design: Cross sectional study. Methods: Forty healthy volunteers performed the navicular drop test in three different combinations of non-weight-bearing and weight-bearing postures (standing/standing, sitting/sitting, and sitting/standing). Two examiners alternately performed the measurements five times in each subject, and in each posture. Significant differences in measurements were obtained among the three postures, with the highest navicular drop being observed in the sitting/standing posture. Results: Inter-rater reliability was high in the sitting/standing and sitting/sitting postures. Intra-rater reliability was high in all three postures. In the sitting/sitting and sitting/standing postures, large navicular drop values and high inter- and intra-rater reliability were observed. Conclusion: Therefore, the sitting/standing and sitting/sitting postures are recommended for use in navicular drop tests to diagnose flat feet.

• Physical Therapy Korea
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• v.27 no.3
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• pp.199-205
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• 2020

Background: The classification of foot type can be commonly determined by the height of the media longitudinal arch. The normalized arch height (NAH) is defined as the ratio of navicular or instep heights to the foot length or instep length. Objects: This study investigated the relationships among foot characteristics, such as foot length (FL), instep length (IL), navicular height (NH), and instep height (IH), in Korean young adults. Also, the distribution of foot type based on calculated NAH was assessed. Methods: Three-dimensional foot scanning data of young adults aged 20 to 39 years (total: 1,978; 974 male, 1,004 female) were obtained from the Korea Technology Standards Institute, and used for analyses. NAH was calculated as the following: NH/FL, IH/FL, IH/IL, NH/IL. Spearman's rank order correlation was used to identify correlations among variables. The Mann-Whitney U-test and chi-square test were used to compare the sex differences in foot characteristics and distribution of foot type. Results: FL and IL showed a very high correlation (r = 0.94). The correlations between FL or IL and IH (r = 0.50-0.57) were greater than those between FL or IL and NH (r = 0.23-0.72). Males had significantly larger values than females (p < 0.001), and the frequency of pes planus was significantly higher in females than in males (χ² = 50.09, p < 0.001). Based on the IH/IL index, the neutral foot, pes planus and pes cavus distributed by 16%, 78%, and 6% respectively. Conclusion: Our results on foot arch distribution could be used as basic data in clinical or footwear fields, and our data on differences in arch structure according to sex may facilitate understanding of why injury to the lower limbs differs between males and females.

• Journal of the Korea Society of Computer and Information
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• v.26 no.4
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• pp.21-28
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• 2021

This study proposes a deep learning-based flat foot classification methodology using transfer learning. We used a transfer learning with VGG16 pre-trained model and a data augmentation technique to generate a model with high predictive accuracy from a total of 176 image data consisting of 88 flat feet and 88 normal feet. To evaluate the performance of the proposed model, we performed an experiment comparing the prediction accuracy of the basic CNN-based model and the prediction model derived through the proposed methodology. In the case of the basic CNN model, the training accuracy was 77.27%, the validation accuracy was 61.36%, and the test accuracy was 59.09%. Meanwhile, in the case of our proposed model, the training accuracy was 94.32%, the validation accuracy was 86.36%, and the test accuracy was 84.09%, indicating that the accuracy of our model was significantly higher than that of the basic CNN model.

• Journal of Korean Physical Therapy Science
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• v.18 no.2
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• pp.51-62
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• 2011

Purpose: The purpose of this study was to investigate the effect of microcurrent on fatigue of muscles in people who were flat-footed during gait. Methods: 10 flat-footed university students volunteered to participate in this study. 10 flat-footed subjects were divided into 2 groups, one group was experimental group of 5subjects(This group put on microcurrent induction shoes but the subjects were not able to feel the current.) and the other group was the control group of 5subjects(This group put on the general shoes which were similar in shape but microcurrent was not induced.) to perform double blind test and random sampling. Their gait muscle fatigue of 6 regions (vastus medialis, gastrocnemius, tibialis anterior, biceps femoris, erector spinae, and rectus abdominis muscle.) was measured by EMG MP150, Delsys Inc Boston, USA during walking and then they carried out the Harvard step with a platform (It was a arbitrarily made wooden platform of 100cm long, 50cm wide, 60cm high. They carried out climbing it for one second and descending it for one second by using the Metronome program, total 5minutes) for 5minutes. Right after that, the subjects walked on a treadmill at a speed of 4km/h for 10minutes and then their gait muscle fatigue of 6regions was assessed while they were walking on the ground as equally as before exercise. Results: The experimental group has resulted in lower average differences in gait muscle fatigue before and after exercise than those of the control group average 12.24Hz(P=0.009) at vastus medialis, average 8.52Hz(P=0.016) at gastrocnemius, average 9.16Hz(P=0.009) at tibialis anterior, average 8.66Hz(P=0.047) at biceps femoris, average 7.53Hz(P=0.016) at erector spinae, and average 7.80Hz(P=0.047) at rectus abdominis. All of the assessments of muscles have shown significant difference statistically. Conclusions: This result has shown that the use of micro current could decrease gait muscle fatigue of flat-footed people. It is recommended to use a microcurrent to reduce their gait muscle fatigue.

• Journal of Korean Foot and Ankle Society
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• v.18 no.2
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• pp.43-47
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• 2014

Hallux valgus is a lateral deviation of the first phalanx and medial deviation of the first metatarsal at the first metatarsophalangeal (MP) joint. Its incidence has increased due to developing footwear. The etiologies include fashion footwear, genetic causes, anatomical abnormality around the foot, rheumatoid arthritis, and neuromuscular disorders. Physiologic alignment of the first MP joint is maintained by congruent and symmetric alignment of the articular surface of the first proximal phalanx and first metatarsal head, physiologic relationship of the distal first metatarsal articular surface and the first metatarsal shaft axis, and stable balance of soft tissue around the first MP joint and stable tarsometatarsal joint. Several factors have been associated with hallux valgus, including pes planus, hypermobility of the first tarsometatarsal joint, flattened shape of the first metatarsal head, increased distal metatarsal articular angle, and deformation of the medial capsular integrity. History and physical examination are very important to diagnosis of hallux valgus. Simple radiography provides information on deformity, particularly in weight-bearing anteroposterior and lateral radiographs. Understanding the etiologies and pathophysiology is very important for success in treatment of patients with hallux valgus.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.67-73
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• 2010

The foot performs an important function in supporting the body and keeping body balance. An abnormal walking habit breaks the balance of the human body as well as the normal function of the foot. The influence of a flatfoot(pes planus) occupies a considerable portion of the various causes resulting in the wrong walking habit. But, little studies has been done by the functional foot orthotics for the flat foot. The object of this study, therefore, is to propose a new approach method to reveal the effects of the improvement of the foot function by using orthotics. The essential point of this study is to measure and analyze the change of ankle angle in the sagittal plane for flat foot subjects wearing the orthotics. Before and after wearing the functional orthotics, the gait analysis of flat foot subjects was conducted in three experimental aspects : the change of ankle angle, the change of the total Ankle ROM and the difference of left & right ankle angle in the sagittal plane. 1. The average ankle angle differences of before-and-after wearing the orthotics have declined like this; left : $2.71^{\circ}$, right: $1.91^{\circ}$ (p<0.05). 2. Total ankle ROM also showed decrease in both sides while the left side's is rather slight; left : $0.57^{\circ}$, right : $2.07^{\circ}$ (p<0.05). 3. The difference of left and right ankle angle in the sagittal plane decreased by $0.71^{\circ}$ (p<0.05). In result, it is confirmed that the functional foot orthotics have a significant effect on mechanical movement of ankle joint for flat foot. it is expected that this paper will be further studied and improved as a practical estimation method in the research on the effect of foot-orthotics.

• Physical Therapy Korea
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• v.26 no.4
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• pp.70-76
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• 2019

Background: An excessive pronated foot is defined as a flattening or complete loss of the medial longitudinal arch. Excessive foot pronation is considered to have high risk factors of overuse injuries in the lower limb. Various treatments have been investigated in attempts to control excessive pronation. Objects: This meta-analysis identifies the effects of an anti-pronation taping technique using different materials. Methods: The electronic databases used include MEDLINE, the Physiotherapy Evidence Database (PEDro), Science Direct, the Korean Studies Information Service System (KISS), the Research Information Sharing Service (RISS), the Korea National Library, and the Korean Medical Database (studies published up to July 31, 2019). The database search used the following keywords: "foot drop" OR "foot arch" OR "foot pronation" OR "flat foot (pes planus)" AND "taping" OR "support." Eight eligible studies were analyzed to determine the effectiveness of anti-pronation taping in study and control groups. Results: The overall random effect size (Hedges'g) of the anti-pronation taping technique was 0.147 (95% confidence interval [CI]: -.214 to .509). When the effect (Hedges' g) was compared by the type of tape material, rigid tape (RT; Lowdye taping) was .213 (95% CI: -.278 to .704) and kinesiotape (KT; arch support taping) was -.014 (95% CI: -.270 to .242). Based on this meta-analysis, it was not possible to identify the extent to which anti-pronation taping was effective in preventing navicular drop, improving balance, or changing foot pressure. Only three of the eight eligible studies applied KT on excessive pronated feet, and the outcome measure areas were different to those of the RT studies. The KT studies used EMG data, overall foot posture index (FPI) scores, and rear foot FPI scores. In contrast, the RT studies measured navicular heights, various foot angles, and foot pressure. Conclusion: This review could not find any conclusive evidence about the effectiveness of any taping method for patients with pronated feet. Future studies are needed to develop the anti-pronation taping technique based on the clinical scientific evidence.

• Physical Therapy Korea
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• v.28 no.4
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• pp.266-272
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• 2021

Background: Considering the kinetic chain of the lower extremity, a pronated foot position (PFP) can affect malalignment of the lower extremity, such as a dynamic knee valgus (DKV). Although the DKV during several single-leg movement tests has been investigated, no studies have compared the differences in DKV during a single-leg step down (SLSD) between subjects with and without PFP. Objects: The purpose of this study was to compare the DKV during SLSD between subjects with and without PFP. Methods: Twelve subjects with PFP (9 men, 3 women) and 15 subjects without PFP (12 men, 3 women) participated in this study. To calculate the DKV, frontal plane projection angle (FPPA), knee-in distance (KID), and hip-out distance (HOD) during SLSD were analyzed by two-dimensional video analysis software (Kinovea). Results: The FPPA was significantly lower in PFP group, compared with control group (166.4° ± 7.5° and 174.5° ± 5.5°, p < 0.05). Also, the KID was significantly greater in PFP group, compared with control group (12.7 ± 3.9 cm and 7.3 ± 2.4 cm, p < 0.05). However, the HOD not significantly differed between two groups (12.7 ± 1.7 cm and 11.4 ± 2.5 cm, p > 0.05). Conclusion: The PFP is associated with lower FPPA and greater KID. When assess the DKV during SLSD, the PFP should be considered as a crucial factor for occurrence of DKV.

• PNF and Movement
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• v.19 no.2
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• pp.279-285
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• 2021

Purpose: This study aimed to develop new digital navicular drop test (ND-NDT) equipment and to determine its validity and reliability. Methods: A total of 24 healthy male and female adults, who fully understood the purpose of the study and gave consent to participate in the study, were selected as participants. The NDT and ND-NDT were conducted in the dominant foot of the participants in a random order. For the NDT, the position of the navicular bone was marked with a pen first; then, the height of the navicular bone from the ground was measured in both sitting and standing positions. For the ND-NDT, after the sticker-type reflection markers were attached to the position of the navicular bone, the height of the navicular bone from the ground was measured in both sitting and standing positions. To assess the validity of the diagnostic tests, the same examiner measured the height of the medial longitudinal arch (MLA) three times in both the sitting and standing positions. To assess the inter-rater reliability of the ND-NDT, three examiners, in a random order, attached the sticker-type reflection markers to the position of the navicular bone and then measured the height of the MLA in both positions. Results: In the sitting position, the Pearson correlation coefficient (r) between the two diagnostic tests was very high (r = 0.97) and statistically significant. In the standing position, the Pearson correlation coefficient (r) between the two tests was 0.95, which was also statistically significant. The ICC_2,1 values in the sitting and standing positions were 0.93 and 0.95, respectively, indicating significantly high inter-rater reliability. Conclusion: The ND-NDT equipment showed very high diagnostic validity, as well as excellent inter-rater reliability, indicating the clinical usefulness of the equipment as a diagnostic system for confirming pes planus.