• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.5
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• pp.701-710
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• 2009

This study was conducted to develop excellent insole with good thermal insulation using new materials. We investigated that aerogel/fiber composite can be used as padding materials of shoes by comparing surface shape, moisture regain, water vapor permeability, thermal insulation and compression rate of insole materials tried with nonwoven fabric padding materials and insole sold in market. The results are as follows. Surface shapes were shown that the most appropriate material for sealing aerogel/fiber composite was high density fabric as per size of particle of aerogel. Moisture regain of aerogel/fabric composite was better than nonwoven fabric padding samples. However, when compared to insole sold in market, its moisture regain was worse than those of insole merchandises. Water vapor permeability was higher in material padded with nonwoven fabric than materials padded with aerogel/fiber composite in all three kinds of sealing fabrics. Thermal conductivity of aerogel/fabric composite was lower than nonwoven fabric material regardless of sealing fabrics. Thermal insulation of aerogel/fiber composite was higher than padding material of nonwoven fabric regardless of sealing fabrics. Compression rate of nonwoven (SP1) was higher than that of aerogel/fiber composite (SP2). Compressive elastic recovery rate of SP1 was also higher than that of SP2, which its compression rate and compressive elastic recovery rate were both poor. As the above result, ultra porous aerogel/fiber composite were proved to be material of good thermal insulation with lower thermal conductivity and also compression rate was proved to be low. Therefore, we can say that aerogel/fiber composite have high possibility to be used as insole materials for cold winter shoes requiring good thermal insulation protection.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.1
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• pp.110-122
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• 2023

The COVID-19 pandemic increased people's time at home and caused an 80% increase in noise disputes between floors. The purpose of this study is to propose suitable materials for making indoor shoes (insoles) to minimize noise between floors. Subjects without back pain and leg-related disease (e.g. arthritis, etc.) from three different age groups (childhood, adolescence, and adulthood) were recruited for the study. Five polymer insole materials were considered: Chloroprene Rubber (CR foam), Ethylene Propylene Diene Monomer (EPDM foam), Natural Latex foam, Ethylene Vinyl Acetate (EVA foam), and Polyurethane (PU foam). From these materials, 20 combinations were prepared and randomly tested for noise and vibration. The results revealed a significant difference in noise and vibration levels based on the type of material used and the age of the subject. Nevertheless, all materials under consideration successfully reduced noise and vibration; in particular, type A-C greatly decreased. The CR foam material was especially effective at noise and vibration reduction (p<.01). This study suggests that adding insoles into socks that children wear at home could reduce noise vibration and disputes between floors.

• Journal of Korean Foot and Ankle Society
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• v.24 no.3
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• pp.113-119
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• 2020

Purpose: A flatfoot that fails to form a longitudinal foot arch is a common lower limb deformity in children. This study evaluated the structural and functional effects of the insole for pediatric flexible flat foot (PFFF). Materials and Methods: Twenty-nine PFFF patients (20 boys and 9 girls, 58 feet) with bilateral symptomatic flatfoot deformities between February 2017 and May 2019 were included in this study. Sixteen patients (32 cases, study group) were treated with a pressured based 3-dimensional printing insole, and 13 patients (26 cases, control group) were followed up regularly without any treatment. Flatfoot was diagnosed by a lateral talo-first metatarsal angle of more than 4° in convex downward and talocalcaneal angles of more than 30° and a calcaneal pitch of less than 20°. The foot pressures, including the midfoot pressure, total foot pressure, and the ratio of the midfoot pressure to the total foot pressure, were evaluated by pedobarography. The clinical scores were assessed using the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS), and Pediatrics Outcomes Data Collection Instrument (PODCI) scores. Results: The mean age of the study group was 9.16 years, and the mean age of the control group was 7.73 years. The mean follow-up period was 16 months. The change in the lateral talocalcaneal angle was -4.664°±1.239° in the study group and -0.484°±1.513° in the control group. A significant difference in the amount of change of the lateral talocalcaneal angle was observed between the two groups (p=0.034). The midfoot pressures were similar in the two groups. Conclusion: Pressure based customized 3-dimensional printing insole in PFFF may have some effect on the hindfoot bony alignment, but it does not affect the changes in midfoot pressure.

• Journal of Biomedical Engineering Research
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• v.24 no.1
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• pp.31-36
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• 2003

Impact characteristics of six DM(Diabetes Mellitus) shoe insole materials (Podian, Plastazote black, Plastazote white, Flexible PU foam, Podialene 200 blue and Podia flex) and three multi-density insoles (AP, OS and PW insoles) were determined in the present study, using a self-designed impact measurement system. The coefficient of restitution, the median frequency and the attenuation index were calculated for each material, based on impact forces and linear accelerations. Podian revealed the superiority in the coefficient of restitution and the attenuation index. The median frequency of the Flexible PU foam was the smallest. Results also showed that the heel region was the most impact-attenuated among other areas in the insole. OS insole showed the better characteristics in the coefficient of restitution and the median frequency. but there was no significant difference in the attenuation index. Similar impact characteristics were found in all areas in PW insole. since it was basically of the same dual-density polyurethane.

• Korean Journal of Applied Biomechanics
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• v.21 no.2
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• pp.231-241
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• 2011

The purpose of this study was to analyze the distribution of foot pressure generated by active materials of a functional insole. Comfort is an important consideration while selectingfootwear and insoles. Consequently, it has an influence on injury. The development of new materials for functional insoles is considered one of the more important points for their manufacture. The method adopted in this study is as follows. First, ten healthy males were selected as subjects for the study. Each subject's foof was pre-screened podoscope(Alfoots, Korea) to check for the presence of any foot abnormalities, Two kinds of equipment were used for the study: a foot pressure device from Pedar-X, Germany, and a treadmill from Pulsefitness, UK. Next, each subject was asked to test four types of insoles(insoles of outdoor shoes, indoor shoes, walking shoes, and sports shoes) via walking trials on the treadmill at a constant speed of 4.2 km/h. The pressure distribution data(contact area, maximum force, maximum peak pressure, and maximum mean pressure) was collected using the pressure device at a sampling rate of 100 Hz. Results of the tests showed that all four types of functional insoles increased contact areas whit the foot. Further, functional insoles of walking shoes and sport shoes decreased the foot pressure. From these results, we conclude that the active materials of functional insoles of shoes can increase the contact area and provide greater comfort.

• Composites Research
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• v.34 no.6
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• pp.400-405
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• 2021

In this study, a composite material frame was designed to increase the energy harvesting efficiency of polyvinylidene fluoride (PVDF) ribbon harvesters which are installed inside smart shoes. In order to minimize the amount of deformation in the load direction of the frame, it was designed using carbon continuous fiber composites and its complex shaped structure was manufactured using a 3D printer. In order to calculate the amount of deformation of the insole and midsole of the shoes under the condition of the load generated during walking, the insole and midsole were modeled using the distributed spring elements. Using finite element analysis, the elongation of ribbon-type harvesters mounted on smart shoes was calculated during walking. It is expected that the predicted elongation of the harvester can be utilized to increase the energy harvesting efficiency of smart shoes.

• Journal of the Ergonomics Society of Korea
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• v.11 no.2
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• pp.23-33
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• 1992

The distribution of the pressure between the sole of a feet and a supporting surface can reveal the information about the structure and fonction of the foot and the posural control of the whole body. In particular, the measurement of the vertical contact forces between the plantar surface of the foot and the shoe insole is of great importance to reveal the loading distributio patterns incurred from a particular shoe midsole design. In order to investigate the plantar surface pressure distribution, an insole-type sensor with a piezoelectric material is developed and tested. The present paper describes a new method to completely reduce both the shear force and pyroelectric effects that are normally caused from piezoelectric materials.

• Composites Research
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• v.34 no.3
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• pp.161-166
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• 2021

In this study, we present a research method to develop a shoe that prevents foot injury by inducing the foot pressure. An orthogonal grid sensor was used to check the foot pressure in the upright standing position, and the change in the foot pressure distribution for various conditions was compared. We checked the conditions for distributing foot pressure efficiently by changing the spring constant of the spring inserted into the sole of the shoe and the foot pressure generated with or without the arch of the insole. In order to minimize the experimental error from the randomness of the human body's behavior, it is possible to predict through foot pressure under certain conditions through finite element analysis that simulates the pressure distribution. By checking the change of foot pressure according to the number and arrangement of springs through finite element analysis, conditions were established to provide more efficient foot pressure. The result can be used for designing footwear for patients with diabetic feet.

• Journal of Korean Foot and Ankle Society
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• v.8 no.1
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• pp.16-21
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• 2004

Purpose: To investigate the characteristics of the patients and therapeutic shoes for diabetic patients. Materials and Methods: Forty two diabetic patients who had their own therapeutic shoes which were prescribed somewhere else were studied from March 2003 to December 2003. There were 27 males and 15 females, and the mean age was 62.1 years (range, 49-72 years). Duration of diabetes was average 14 years (range, $6{\sim}30$ years), all had type 2 diabetes. Sensation was examined with 5.07 nylon monofilament. The route of purchasing the shoes, compliance to the prescribed shoes were investigated by interview. The shape of shoe, stiffness of upper, conformity of insole to the shape of the foot were recorded. In-shoe plantar pressure was measured in 15 patients. Results: Eighteen patients were insensate to the monofilament. Seven patients did not wear the therapeutic shoes, and only 18 of 35 patients were wearing the therapeutic shoes more than 6 hours a day. The shoes of 17 patients were prescribed by medical doctor and the rest were purchased by the recommendation of acquaintances or advertisement. Ulcer recurred in four of five patients to whom the shoe was prescribed by medical doctor and the cause of three recurrences were evident by just observing the foot and shoe. The therapeutic shoes were made from 11 different makers. Eight shoes were adequate for diabetic patients with respect to the material, shape of insole, type of shoe. In-shoe plantar pressure was examined in 15 patients and was less than 300 kPa in all patients. Conclusion: The therapeutic shoes for the diabetic patients need to be prescribed by medical doctor for selective patients with neuropathy or previous history of ulcer and follow-up examination is important to monitor the compliance of the patients and adequacy of the shoes.

• Journal of Korean Foot and Ankle Society
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• v.26 no.3
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• pp.130-135
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• 2022

Purpose: Smart insoles are wearable devices that are inserted into shoes. Smart insoles with built-in pressure and acceleration sensors can measure the plantar pressure, stride length, and walking speed. This study evaluated the validity and reliability of the plantar pressure measurements of smart insoles during walking on flat ground. Materials and Methods: Twenty one subjects were included in this study. After wearing smart insoles, I-SOL^® (Gilon, Seongnam, Korea), the subjects walked a 10 m corridor six times at a rate of 100 steps/min, and the middle three steps, free from direction changes, were chosen for data analysis. The same protocol was repeated after wearing Pedar-X (Novel Corporation, Munich, Germany), an insoletype plantar pressure measurement equipment with proven validity. The average maximum pressure (P_peak, kPa) and the time at which P_peak appeared (P_time, %stride) were calculated for each device. The validity of smart insoles was evaluated by using the interclass correlation coefficient (ICC) of P_peak and P_time between the two instruments, and Cronbach's alpha was obtained from the P_peak values to evaluate the reliability. Results: The ICC of P_peak was 0.651 (good) in the hallux, 0.744 (good) in the medial forefoot, 0.839 (excellent) in the lateral forefoot, and 0.854 (excellent) in the hindfoot. The ICC of P_time showed 0.868 (excellent) in the hallux, 0.892 (excellent) in the medial forefoot, 0.721 (good) in the lateral forefoot, and 0.832 (excellent) in the hindfoot. All ICC values showed good or excellent results. The Cronbach's alpha of P_peak measured in the smart insoles was 0.990 in the hallux, 0.961 in the medial forefoot, 0.973 in the lateral forefoot, and 0.995 in the hindfoot; all indicated excellent reliability in all areas. Conclusion: The plantar pressure measurements of smart insoles during walking on a flat ground showed validity compared to Pedar-X, and high reliability after repeated measurements.