• Korean Journal of Applied Biomechanics
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• v.26 no.1
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• pp.11-20
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• 2016

Objective: This study aimed to compare biomechanical data between elite and beginner cyclists during cycle pedaling by performing a comparative analysis and to provide quantitative data for both pedaling performance enhancement and injury prevention. Methods: The subjects of this study included 5 elite cyclists (age: $18{\pm}0years$, body mass: $64.8{\pm}9.52kg$, height: $173.0{\pm}4.80cm$) and 5 amateur cyclists (age: $20{\pm}0years$, mass: $66.6{\pm}2.36kg$, height: $175.6{\pm}1.95cm$). The subjects pedaled on a stationary bicycle mounted on rollers of the same gear (front: 50 T and rear: 17 T = 2.94) and cadence of 90. The saddle height was adjusted to fit the body of each subject, and all the subjects wore shoes with cleats. In order to obtain kinematic data, 4 cameras (GR-HD1KR, JVC, Japan) were installed and set at 60 frames/sec. An electromyography (EMG) system (Telemyo 2400T, Noraxon, USA) was used to measure muscle activation. Eight sets of data from both the left and right lower extremities were obtained from 4 muscles (vastus medialis oblique [VMO], vastus lateralis oblique [VLO], and semitendinosus [Semitend], and lateral gastrocnemius [Gastro]) bilaterally by using a sampling frequency of 1,500 Hz. Five sets of events ($0^{\circ}$, $90^{\circ}$, $180^{\circ}$, $270^{\circ}$, and $360^{\circ}$) and 4 phases (P1, P2, P3, and P4) were set up for the data analysis. Imaging data were analyzed for kinematic factors by using the Kwon3D XP computer software (Visol, Korea). MyoResearch XP Master Edition (Noraxon) was used for filtering and processing EMG signals. Results: The angular velocity at $360^{\circ}$ from the feet was higher in the amateur cyclists, but accelerations at $90^{\circ}$ and $180^{\circ}$ were higher in the elite cyclists. The amateur cyclists had greater joint angles at $270^{\circ}$ from the ankle and wider knee joint distance at $0^{\circ}$, $180^{\circ}$, and $360^{\circ}$ than the elite cyclists. The EMG measurements showed significant differences between P2 and P4 from both the right VLO and Semitend. Conclusion: This study showed that lower body movements appeared to be different according to the level of cycle pedaling experience. This finding may be used to improve pedaling performance and prevent injuries among cyclists.

• The Journal of the Korean bone and joint tumor society
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• v.8 no.3
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• pp.76-82
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• 2002

Purpose: Benign bone tumor of the talar body have rarely been evaluated according to the therapeutic methods because of the scarcity of their incidence. Here, we report our experience of 8 cases who were treated by using of posterior approach and curettage through the posterior process of the talus. Materials and Methods: Between February 1986 and October 2001, we experienced 8 cases of benign bone tumor occurring in the talar body. They included two osteoid osteomas, two giant cell tumors, one capillary hemangioma, one chondroblastoma, one simple bone cyst, and one osteochondroma. Their mean age was 22.1 years (ranging from 10 to 41 years). Mean follow-up period was 7.7 years (ranging from 1 to 16 years). All patients were treated by using of posterior approach. Two osteoid osteomas and one osteochondroma were treated by excision of tumors. Other cases were treated with curettage through the cortical window on the posterior process of the talus. Results: There was no recurrence during the follow-up period. one infection occurred. Except this case, all patients had no pain in weight-bearing, and complete range of movement at the ankle joint was reserved in each case. Conclusion: In this study, we suppose that posterior approach to the talar body may be a safe method with minimal damage of normal tissues and sufficient of curettage is capable through the cortical window on the posterior process of the talus.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.2
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• pp.137-144
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• 2015

In this paper, we present an inertial sensor-based gait analysis system to measure and analyze lower-limb movements. We developed an integral AHRS(Attitude Heading Reference System) using a combination of rate gyroscope, accelerometer and magnetometer sensor signals. Several AHRS modules mounted on segments of the patient's body provide the quaternions representing the patient segments's orientation in space. And a method is also proposed for calculating three-dimensional inter-segment joint angle which is an important bio-mechanical measure for a variety of applications related to rehabilitation. To evaluate the performance of our AHRS module, the Vicon motion capture system, which offers millimeter resolution of 3D spatial displacements and orientations, is used as a reference. The evaluation resulted in a RMSE(Root Mean Square Error) of 1.08 and 1.72 degree in yaw and pitch angle. In order to evaluate the performance of our the gait analysis system, we compared the joint angle for the hip, knee and ankle with those provided by Vicon system. The result shows that our system will provide an in-depth insight into the effectiveness, appropriate level of care, and feedback of the rehabilitation process by performing real-time limb or gait analysis during the post-stroke recovery.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.3952-3958
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• 2011

This study was to investigate the difference in gait pattern between the visual handicap children and non handicap children in by analyze the biomechanical variation and pattern of lower limb. Therefore, we have made a choice of four visually handicapped children and two subjects, who had no medical disorder for the last six months. In order to collect the gait pattern data of each group, we have used six infrared cameras and one forceplate Also, we have used QTM program to collect the raw data and Visual3D program to calculate kinetic variable. The results were as follows, An/Posterior GRF of breaking phase and propulsion phase in stance phase was lower in visual handicapped children than that of non handicapped children and breaking phase was longer than propulsion phase. extension moment at the ankle was quite lower than general gait pattern and there was little variation at the knee joint which makes the results differ from the general gait pattern. However, hip joint moment was relatively higher than that of other joints. Mechanical variation of lower limb, in case of foot and shank, showed similar results. but generated very low mechanical energy. In thigh, the form of mechanical energy generation was slightly different in each group but generated more mechanical energy than other segments.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.17-23
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• 2022

Objective: The aim of this study was to investigate the effect Tiger-step walking on the movement of the lower extremities during walking. Method: Twenty healthy male adults who had no experience of musculoskeletal injuries on lower extremities in the last six months (age: 26.85 ± 3.28 yrs, height: 174.6 ± 3.72 cm, weight: 73.65 ± 7.48 kg) participated in this study. In this study, 7-segments whole-body model (pelvis, both side of thigh, shank and foot) was used and 29 reflective markers and cluster were attached to the body to identify the segments during the gait. A 3-dimensional motion analysis with 8 infrared cameras and 7 channeled EMG was performed to find the effect of tigerstep on uphill walking. To verify the tigerstep effect, a one-way ANOVA with a repeated measure was used and the statistical significance level was set at α=.05. Results: Firstly, Both Tiger-steps showed a significant increase in stance time and stride length compared with normal walking (p<.05), while both Tiger-steps shown significantly reduced cadence compared to normal walking (p<.05). Secondly, both Tiger-steps revealed significantly increased in hip and ankle joint range of motion compared with normal walking at all planes (p<.05). On the other hand, both Tiger-steps showed significantly increased knee joint range of motion compared with normal walking at the frontal and transverse planes (p<.05). Lastly, Gluteus maximus, biceps femoris, medial gastrocnemius, tibialis anterior of both tiger-step revealed significantly increased muscle activation compared with normal walking in gait cycle and stance phase (p<.05). On the other hand, in swing phase, the muscle activity of the vastus medialis, biceps femoris, tibialis anterior of both tiger-step significantly increased compared with those of normal walking (p <.05). Conclusion: As a result of this study, Tiger step revealed increased in 3d range of motion of lower extremity joints as well as the muscle activities associated with range of motion. These findings were evaluated as an increase in stride length, which is essential for efficient walking. Therefore, the finding of this study prove the effectiveness of the tiger step when walking uphill, and it is thought that it will help develop a more efficient tiger step in the future, which has not been scientifically proven.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.1
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• pp.109-116
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• 2023

The purpose of this study was to investigate the influence of gender and load carriage difference on the lower extremity kinetics during stair descent. Ten healthy males and 10 healthy females were recruited (n=20). In the Maximum resultant velocity, it showed more velocity was decreased with difference by the change of gender (males>females) and load carriage (30%, 20%, 10%> 10%). And, resultant velocity showed interaction between gender and a load (load>gender). Main effect by gender during stair descent showed leg length was decreased in females than that of males at initial contact phase. Also, main effect by gender during stair descent showed more hip, knee flexed and plantar flexion of ankle joint in females than that of males. In the kinetics variables, main effect by gender during stair descent showed more higher reaction force of medial-lateral direction, and leg stiffness in males than that of females. We found that females successfully accommodated a load during stair descent by decreasing the range of motion of the hip joint angle and resultant velocity of movement. Males, on the other hand, require greater medial-lateral, vertical reaction force, and leg stiffness to accommodate a load, and control of momentum.

• The Journal of Korean Society for Radiation Therapy
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• v.23 no.2
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• pp.91-96
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• 2011

Purpose: The aim of study is to expose a more uniform dose depending on the relationship between a body mass index in patients who underwent radiation therapy and an acquired dosimetric information by using a thermoluminescent dosimeter. Materials and Methods: Since 2006 to August 2011 we investigated 28 people who underwent radiation therapy were enrolled in AMC. Each patient was measured on the head, neck, chest, abdomen, pelvis, thigh, knee joint, and ankle joint using the thermoluminescent dosimeter. The measurement value of each points compared with the prescribed center point, abdominal point, and dose measurements of points on which to base the abdomen and the patient's body mass index (BMI) were compared with reference point, abdomen dose. Results: 28 patients on prescribed dose in the abdomen by which the center point, an average dose was $100.6{\pm}5.5%$, and the other seven measuring points with the average maximum difference among the head, neck, chest, pelvic, thigh, knee, and ankle were $92.8{\pm}4.2%$, $97.6{\pm}6.2%$, $96.4{\pm}5.5%$, $102.6{\pm}5.3%$, $103.4{\pm}7.9%$, $95.8{\pm}5.9%$, $96.1{\pm}5.5%$. The relationship of abdominal point dose and the patient's body mass index (BMI) was analyzed a scatter plot, and the result of linear relationship analysis by regression method, the regression of the dose (y) was -1.009 BMI (x) plus 123.3 and coefficient of determination ($R^2$) was represented 0.697. Conclusion: The total body irradiation treatment process was evaluated the dose deviation and then the prescribed dose by which the average abdominal dose was satisfied with $100.6{\pm}5.5%$. Results of the relationship analysis between BMI and dose, if we apply the correction value for each patients, it can be achieved more uniform dose delivery.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.224-233
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• 2021

Purpose: The purpose of this study was to retrospectively evaluate the effect of 'Blocking Kirschner Wire (K-Wire) Technique', which has been developed to reduce protrusion of the lateral wall, in maintaining the level of reduction through clinical and radiological outcomes. Materials and Methods: Twenty-two patients with displaced intra-articular calcaneal fractures who used the blocking K-wire to maintain reduction (group A) and 44 patients that did not use blocking K-wire and were paired in 1:2 ratio with those Group A patients (group B), between January 2015 and December 2017 were enrolled in the study. All surgical procedures were performed via the extended sinus tarsi approach, and internal fixation using cannulated screws, Steinmann pins and K-wires was performed. American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale and postoperative recovery of exercise ability were compared for postoperative clinical outcomes. The radiological results were compared the Böhler angle, Gissane angle, calcaneal height and width, step off of posterior calcaneal joint, and the degree of protrusion of the lateral wall. Moreover, postoperative complications in both groups were compared. Results: There were no significant differences in the clinical outcomes of the two groups (p=0.924, p=0.961). The amount of Böhler angle, Gissane angle, calcaneal height and width, and step off of posterior calcaneal joint from the radiological results was not significantly different between the two groups (p=0.170, p=0.441, p=0.230, p=0.266, and p=0.400). However, the degree of protrusion of the lateral wall was 1.78 mm and 4.95 mm in group A and group B, respectively, and the difference between the two groups was significant (p=0.017). Although sural nerve entrapment and painful exostosis were more frequent in group B, they were occurred in a non-significant manner (p=0.293, p=0.655). Conclusion: Most of the clinical and radiological results as well as the complications were not significantly different between the two groups. However, the degree of protrusion of the calcaneus lateral wall in group A was promising. The 'Blocking K-Wires Technique' established by the authors may be an effective surgical option for maintaining the reduction of the lateral wall protrusion in displaced intraarticular calcaneal fractures.

• 재활복지
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• v.14 no.3
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• pp.225-256
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• 2010

This study aims to provide the basic data of the rehabilitation program for the schoolchild with intellectual disability by designing new framework of the features of postural control for the schoolchild with intellectual disability. For this, the study investigated what sensations the schoolchild are using to maintain posture by selectively or synthetically applying vision, vestibular sensation and somato-sensation, and how the coordinative sensory system of the schoolchild is responding to any sway referenced sensory stimulus. The study intended to prove the limitation of motor system in estimating the postural stability by providing the cognitive motor task, and provided the features of postural control of the schoolchild with intellectual disability by measuring the onset times and orders of muscle contraction of neuron-muscle when there is a postural control taking place due to the exterior disturbance. Furthermore, by comparatively analyzing the difference between the normal schoolchild and the intellectually disabled schoolchild, this study provided an optimal direction for treatment planning when the rehabilitation program is applied in the postural control ability training program for the schoolchild with intellectual disability. Taking gender and age into consideration, 52 schoolchild including 26 normal schoolchild and 26 intellectually disabled schoolchild were selected. To measure the features of postural control, CTSIB test, and postural control strategy test were conducted. The result of experiment is as followed. First, the schoolchild with intellectual disability showed different feature in using sensory system to control posture. The normal schoolchild tended to depend on somato-sensory or vision, and showed a stable postural control toward a sway referenced stimulus on somato-sensory system. The schoolchild with intellectual disability tended to use somato-sensory or vision, and showed a very instable postural control toward a sway referenced vision or a sway referenced stimulus on somato-sensory system. In sensory analysis, the schoolchild with intellectual disability showed lower level of proficiency in somato-sensation percentile, vision percentile and vestibular sensation percentile compare to the normal schoolchild. Second, as for the onset times and orders of muscle contraction for strategies of postural control when there is an exterior physical stimulus, the schoolchild with intellectual disability showed a relatively delayed onset time of muscle control, and it was specially greater when the perturbation is from backward. As for the onset orders of muscle contraction, it started from muscles near coax then moved to the muscles near ankle joint, and the numbers and kinds of muscles involved were greater than the normal schoolchild. The normal schoolchild showed a fast muscle contracting reaction from every direction after the perturbation stimulus, and the contraction started from the muscles near the ankle joint and expanded to the muscles near coax. From the results of the experiments, the special feature of the postural control of the schoolchild with intellectual disability is that they have a higher dependence on vision in sensory system, and there was no appropriate integration of swayed sensation observed in upper level of central nerve system. In the motor system, the onset time of muscle contraction for postural control was delayed, and it proceeded in reversed order of the normal schoolchild. Therefore, when use the clinical physical therapy to improve the postural control ability, various sensations should be provided and should train the schoolchild to efficiently use the provided sensations and use the sensory experience recorded in upper level of central nerve system to improve postural control ability. At the same time, a treatment program that can improve the processing ability of central nerve system through meaningful activities with organizing and planning adapting reaction should be provided. Also, a proprioceptive motor control training program that can induce faster muscle contraction reaction and more efficient onset orders from muscularskeletal system is need to be provided as well.

• Journal of the Korean Orthopaedic Association
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• v.56 no.4
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• pp.317-325
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• 2021

Purpose: This study compared the functional and radiologic outcomes of intramedullary nailing (IMN) and minimally invasive plate osteosynthesis (MIPO) for tibia fractures in distal tibial spiral fractures combined with posterior malleolar fractures, as well as the functional and radiologic outcomes with and without fixation for posterior malleolar fractures. Materials and Methods: From January 2010 to December 2018 the radiological and clinical outcomes of 30 skeletally mature patients with tibial spiral fractures (AO Foundation/Orthopaedic Trauma Association classification 42-A1, B1, C1) combined with posterior malleolar fractures were analyzed. Sixteen patients were treated with IMN, and 14 patients were treated with MIPO. Depending on the surgical methods, the radiologic and clinical outcomes were compared by evaluating the bone union time, postoperative alignment, postoperative displacement of the posterior malleolar fragment, and American Orthopaedic Foot and Ankle Society (AOFAS) score. Moreover, the functional and clinical outcomes with and without fixation for posterior malleolar fractures were compared. Results: The mean bone union time was 21.8 weeks in the IMN group and 23.1 weeks in the MIPO group (p=0.500). At the final follow up, the mean alignment was coronal angulation of 1.8°, sagittal angulation of 1.6° in the IMN group and coronal angulation of 1.2° and sagittal angulation of 1.7° in the MIPO group (conoral angulation: p=0.131, sagittal angulation: p=0.850). The postoperative and final radiologic evaluation showed no displacement of the posterior malleolar fragment and excellent joint congruity in all cases. At the final follow-up, the mean AOFAS score was 88.0 on average in the IMN group and 87.6 on average in the MIPO group (p=0.905). The ankle range of motion and AOFAS score were similar in the fixation group and no fixation group for posterior malleolar fractures. Conclusion: Both IMN and MIPO for tibial spiral fractures combined with posterior malleolar fractures result in satisfactory radiological and clinical outcomes.