• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.95-101
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• 2014

The purpose of this study was to investigate the training and detraining effects of a 8-week water exercise on lower extremities coordination during obstacle gait in the female elderly. Eight elderly participants (age: $76.58{\pm}4.97$ yrs, height: $148.88{\pm}7.19$ cm, body mass: $56.62{\pm}6.82$ kg, and leg length: $82.36{\pm}2.98$ cm), who stayed at the Seoul K welfare center, were recruited for this study. All participants had no history of orthopedic abnormality within the past 1 year and completed the aquatic exercise program which lasted for 8 weeks. To identify the training and detraining effect of 8 weeks of water exercise, a 3-D motion analysis with 7 infrared cameras and one force plate sampling frequency set at 100 Hz and 1,000 Hz, respectively, was performed. A two-way ANOVA was performed to find training and detraining effects among diferent obstacle heights. In this study significant level was set at .05. Significant training effects of LTS (lead foot thigh and shank) coordination in all obstacle height were found (p<.05). It is also found that the training effect of LTS remained 37%, 58%, and 25% in obstacle height of 30%, 40%, and 50%, respectively. Lead foot showed the greater detraining effect of coordination compared with trail foot, and SF (shank and foot) coordination revealed better detraining effects of coordination compare with TS (thigh and shank) in both feet. Based on the findings, a 8 week water exercise give an positive effects to the elderly in terms of segment cooperation which potentially helps reducing their accident falls. The magnitude of detraining may also help the elderly to find the retraining moment.

• Journal of Korean Foot and Ankle Society
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• v.27 no.4
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• pp.137-143
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• 2023

Purpose: Autologous osteochondral transplantation (AOT) is indicated for patients with a large osteochondral lesion of the talus (OLT), accompanying subchondral cyst, and the failure of bone marrow stimulation (BMS) procedures. Despite the many reports on the clinical results of surgical treatment for medial osteochondral lesions, those of lateral lesions are rare. This paper reports the intermediate-term clinical outcomes after AOT for lateral OLTs. Materials and Methods: Twenty-one patients with lateral OLTs were followed up for at least three years after AOT. The clinical evaluations comprised the Foot and Ankle Outcome Score (FAOS) and Foot and Ankle Ability Measure (FAAM). The radiographic assessment included the irregularity of the articular surface (subchondral plate), the progression of degenerative arthritis, and the changes in talar tilt angle and anterior talar translation. Results: The mean FAOS and FAAM scores improved significantly from 42.1 to 89.5 and 39.5 to 90.6 points, respectively, at the final follow-up (p<0.001). The radiological evaluation revealed two cases (9.5%) of articular step-off ≥2 mm and 1 case (4.8%) of progressive arthritis. The mean talar tilt angle and anterior talar translation improved significantly. As postoperative complications, there was one case of a local wound problem, one case of superficial peroneal nerve injury, and one case of donor site morbidity. At a mean follow-up of 62.3 months, no patient showed a recurrence of instability or required reoperation for OLT. Conclusion: AOT for the lateral OLTs demonstrated satisfactory intermediate-term clinical outcomes, including daily and sports activity abilities. Most OLT could be accessed through lateral ligament division and capsulotomy, and the incidence of iatrogenic complications, such as recurrent sprains or chronic instability, was minimal. AOT appears to be an effective and relatively safe treatment for patients with large lateral osteochondral lesions unresponsive to conservative therapy, with subchondral cysts, or with failed primary BMS.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.4
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• pp.1-7
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• 2019

The customer of massage chair is expanding day by day from middle age to all ages. In 2018, the market size was 700 billion KRW, an increase of 30 times over 10 years. However, most related SMEs suffer from excessive competition by the market monopoly of some major companies. In this situation, in order for a related company to survive, it is necessary to steadily research and develop new products. Founded in 2009, company L produces massage chairs for health and relaxation of customers. L's products use a sound wave vibration module that is favorable for human body, unlike other products that use vibration motor type. However, frequent breakdowns of massage chair due to the vulnerability of plate (leaf) springs, which play an important role in sound wave vibration modules, made sap its competitiveness. In this paper, we propose a method to design desirable plate spring structure by sequentially experimenting with five different plate springs. The results of this study are expected to contribute to improve the quality of plate spring and the reliability of sound wave vibration module. In the future, it is necessary to find a way to use it in the development of foot massage or scalp management device as well as continuous research to find optimal plate spring structure through various analysis.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.193-204
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• 2002

The purpose of this study was to investigate the effect of martial art type and target height on the ground reaction force factors during Dollyuchagi motion. Data were collected using force plate. Five Taekwondo players and five Hapkido players were tested during Dollyuchagi motion to three different target heights(0.8, 1.2, 1.6 m). After analysis of kinetics using force plate data, maximum vertical ground reaction force was 1.62~2.44 BW, and impulse was $0.66\sim1.01 BW{\cdot}s$. Even though there was no difference for maximum ground reaction forces and impulse between Hapkido and Taekwondo, as target height was higher, impulse increased. Anterior-posterior and vertical ground reaction forces at kicking foot take-off were greater with target height, although there was no difference for medio-lateral force with target height. At impact there was significant difference for anterior-posterior ground reaction force between Hapkido and Taekwondo players. Taekwondo players' force (range, -0.23~-0.26 BW) was greater than Hapkido players's force (range, -0.08~-0.14 BW).

• Journal of Biomedical Engineering Research
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• v.28 no.2
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• pp.218-228
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• 2007

Modem concepts of gait rehabilitation after stroke favor a task-specific repetitive approach. In practice, the required physical effort of the therapists limits the realization of this approach. Therefore, a mechanized gait trainer enabling nonambulatory patients to have the repetitive practice of a gait-like movement without overstraining therapists was constructed. In this study, we developed an active gait training system for patients with gait disorder. This system provides joint movements to patients who cannot carry out an independent gait. It provides a normal stance-swing ratio of 60:40 using an eccentric configuration of two gears. Joint motions of the knee and the ankle were evaluated with using the 3D motion analysis system and compared with the results from the multi-body dynamics simulation. In addition, clinical investigations were also performed for low stroke patients during the 6-week gait training. Results from the dynamics simulation showed that joint movements of the knee and the ankle were affected by the gear size, the step length and the length of the foot plate, except the radius of curvature of the foot guide plate. Also, the 6-week gait training revealed relevant improvements of the gait ability in all low subjects. Functional ambulation category levels of subjects after training were 2 in three patients and 1 in a patient. The developed active gait trainer seems feasible as an adjunctive tool in gait rehabilitation after stroke.

• Journal of Korean Foot and Ankle Society
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• v.11 no.2
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• pp.221-225
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• 2007

Purpose: To evaluate the clinical results of operative treatment of the intra-articular calcaneal fracture with injectable calcium sulfate ($MIIG^{TM}$). Materials and Methods: Between March 2004 and October 2006, a total 19 intra-articular calcaneal fracture (16 patients) with a large bony defect that underwent operative treatment with plate fixation and injectable calcium sulfate ($MIIG^{TM}$) with minimum follow-up of one year following. The mean age at time of surgery was 44.7 years (23 to 54). All of the cases were type 2 and 3 on the basis of Sanders classification. The lateral L shaped approach was used in all cases. Full weight bearing on the affected extremity was regained at an average 10 weeks postoperatively. Results: The mean Bohler angle was improved from $2^{\circ}$ ($-18.5{\sim}12.5^{\circ}$) preoperatively to $23.8^{\circ}$ ($12{\sim}37.5^{\circ}$) and the angle at last follow-up was $22.5^{\circ}$ ($11.5{\sim}37.5^{\circ}$), showing about 0.3 degree decline compared to postoperative Bohler angle. Only two case of whitish leakage of graft material but other complication were none. Conclusion: $MIIG^{TM}$ augumentation of displaced intra-articular calcaneal fracture with large bone defect seems to bo useful method for initial stabilized and plate fixation.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.3
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• pp.678-684
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• 2009

It was reported that Dipsaci Radix has decrease pain effect on the Complex Region Pain Syndrome(CRPS). the CRPS was induced by unilateral loose occlusion in 4 part of the sciatic nerve of the rats. For the fingding significantly change on CRPS rats were divided into 4 different experimental groups. and each groups were induced CRPS. Experimental group I (control group; n=15), experimental group II (100 mg/kg Dipsaci Radix dieted rats; n=15), experimental group III (300 mg/kg Dipsaci Radix dieted rats; n=15), and experimental group IV(500 mg/kg Dipsaci Radix dieted rats; n=15). The study of Dipsaci Radix concentration was that foot withdrawal threshold to the thermal stimuli(Hot plate test), foot withdrawal threshold to the mechanical stimuli(von Frey's filament) and immunohistochemistry staining that were substance P. Hot plate test and von Frey Filament were increase in experimental group II, III, IV than group I, especially group III was most significantly change than group II and IV in post-hoc(Duncan's multiple range). and In immunohistochemistry observation; group I showed increase in the group II, III, IV. especially group III had the minimal level of the substance P expression while the experimental group II, III. These results suggested that the Dipsaci Radix dieted made the decrease of pain in CRPS.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.1
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• pp.95-102
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• 2023

This study investigated the structural performance of wire-integrated steel decks with varied lattice end support conditions through finite element analysis. The results indicated that the steel decks with the lattice foots positioned above the supporting structural member have the higher system stiffness compared to the cases with the lattice foots shifted away from the support. It is also observed that the contribution of the end vertical bars on both the system stiffness and the strength is negligible when the lattice foots are located on the support. It is, especially, revealed that the end vertical bars can be eliminated when the lattice foot length is not smaller than 40mm. The ultimate load-carrying capacity of the system is not significantly affected by the lattice end support condition. The failure mode of the system is the top bar buckling at the center of the deck plate, the lattice end buckling, and the combination of both depending of design intention.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.151-160
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• 2014

The purpose of this study was to investigate the GRF(ground reaction force) parameters according to the shoes's heel heights and ground landing distances during downward stairs on bus. Participants selected as subject were consisted of young and healthy women(n=9, mean age: $21.30{\pm}0.48$ yrs, mean height: $164.00{\pm}3.05cm$, mean body mass: $55.04{\pm}4.41kg$, mean BMI: $20.47{\pm}1.76kg/m^2$, mean foot length: $238.00{\pm}5.37mm$). They were divided into 2-types of shoe's heel heights(0 cm/bare foot, 9 cm) and also were divides into downward stairs with 3 types of landing distance(20 cm, 35 cm, 50 cm). A one force-plate was used to collect the GRF(AMTI, USA) data from the sampling rate of 1000 Hz. The GRF parameters analyzed were consisted of the medial-lateral GRF, anterior-posterior GRF, vertical GRF, loading rate, Center of Pressure(${\Delta}COPx$, ${\Delta}COPy$, COP area) and Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) during downward stairs on bus. Medial-lateral GRF and vertical GRF didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 9 cm shoes heel showed higher vertical GRF than that of 0 cm bare foot in landing distance of 50 cm. Also anterior-posterior GRF didn't show significant difference statistically according to the shoe's heel heights, but landing distance of 20 cm showed higher than that of landing distances of 35 cm and 50 cm in anterior-posterior GRF. Loading rate didn't show significant difference statistically according to the landing distance, but 9 cm shoe's heel showed higher than that of 0 cm bare foot during downward stairs. The ${\Delta}COPy$ and COP area didn't show significant differences statistically according to the shoe's heel heights and landing distance, but 0 cm bare foot showed higher than that of 9 cm shoe's heel in ${\Delta}COPx$. Dynamic Postural Stability Index(MLSI, APSI, VSI, DPSI) didn't show significant differences statistically according to the landing distance, but 9 cm shoe's heel showed decreased value than that of 0 cm bare foot in dynamics balance. Considering the above, parameters of GRF showed different characteristics according to the shoe's heel heights and ground landing distances during downward stairs on bus.

• Journal of Korean Foot and Ankle Society
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• v.15 no.2
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• pp.62-67
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• 2011

Purpose: The authors evaluated the differences between K-wires and Cannulated screw, plate for fixing the proximal metatarsal chevron osteotomy of moderate and severe hallux valgus. Materials and Methods: There were 62 patients (79 feetz) who were moderate and severe degree hallux valgus according to the classification of Mann. They all got the proximal chevron osteotomy when correcting the deformity. We divided the patients into 4 groups, Two K-wire fixed group as A, one cannulated screw fixed group as B. Two cannulated screw fixed group as C, Plate fixed group as D, Group A were patients (26 feet) and Group B were patients z(9 feet), Group C were patients (31 feet) and Group D were patients (13 feet). Preoperative, postoperative and follow-up hallux valgus angle (HVA) and intermetatarsal angle (IMA) were measured for each patient. ANOVA test and Student t-test were done for statistical analysis. Results: Mean follow up period was 43.8 months (range: 12~82 months). Preoperative mean IMA was $16.4{\pm}3.5$, $17.7{\pm}11.3$, $17.3{\pm}5.9$ and $16.6{\pm}2.3$ degrees in respectively group A, B, C, D. Immediate postoperative mean IMA was $5.6{\pm}3.4$, $7.3{\pm}4.4$, $7.6{\pm}4.4$ and $6.7{\pm}2.8$ degrees in respectively group A, B, C, D. The final mean IMA was $8.9{\pm}4.5$, $15.2{\pm}7.5$, $10.3{\pm}4.4$ and D $7.7{\pm}3.5$ degrees in respectively group A, B, C, D. There were significant statistical increase in final mean IMA of group B and C (p<0.05). Conclusion: The IMA was significantly increased in the group which used one or two cannulated screw for fixation on follow up, therefore more caution should be needed when using one or two cannulated screw fixation technique after proximal chevron osteotomy.