• The Journal of Korean Physical Therapy
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• v.30 no.1
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• pp.14-22
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• 2018

Purpose: This study examined the effects of the lower limb alignment on the pelvis, hip, and knee kinematics in people with genu varum during stair walking. Methods: Forty subjects were enrolled in this study. People who had intercondylar distance ${\geq}4cm$ were classified in the genu varum group, and people who had intercondylar distance <4cm and intermalleolar distance <4cm were placed in the control group. 3D motion analysis was used to collect the pelvis, hip, and knee kinematic data while subjects were walking stairs with three steps. Results: During stair ascent, the genu varum group had decreased pelvic lateral tilt and hip adduction at the early stance phase and decreased pelvic lateral tilt at the swing phase compared to the control group. At the same time, they had decreased minimal hip adduction ROM at the early stance and decreased maximum pelvic lateral tilt ROM and minimum hip rotation ROM at the swing phase. During stair descent, the genu varum group had decreased pelvic lateral tilt at the early stance and decreased pelvic lateral tilt and pelvic rotation at the swing phase. In addition, they had decreased pelvic frontal ROM during single limb support and increased knee sagittal ROM during the whole gait cycle. Conclusion: This study suggests that a genu varum deformity could affect the pelvis, hip and knee kinematics. In addition, the biomechanical risk factors that could result in the articular impairments by the excessive loads from lower limb malalignment were identified.

• Korean Journal of Applied Biomechanics
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• v.14 no.3
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• pp.17-35
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• 2004

The purpose of this study is to explain developmental process of gait via angle-angle diagram to understand how coordinated relationships and control change with age. Twenty four female children, from one to five years of age were the test subjects for this study, and their results were compared to a control group consisting of twenty one adult females. The Vicon 370 CCD camera, VCR, video timer, monitor, and audio visual mixer was utilized to graph the gait cycle for all test subjects. Both coordinated Intra-limb relationships, and range of motion and timing according to quadrant were explained through the angle angle diagram. Movement in the sagittal plane showed both coordinated relationships and control earlier than movement in the coronal or transverse plane. In the sagittal plane, hip and Knee coordinated relationships developed first (from one year of age.) Coordinated relationships in the Knee and ankle and hip and ankle developed next, respectively. Both hip and ankle and knee and ankle development were inhibited by the inability of children to completely perform plantar flexion during the swing and initial double limb support phases. Children appeared to compensate for this by extending at their hip joint more than adults during the third phase, final double limb support. In many cases the angle angle diagram for children had a similar shape as adult's angle angle diagram. This shows that children can coordinate their movements at an early age. However, the magnitudes and timing of children's angle angle diagrams still varied greatly from adults, even at five years of age. This indicates that even at this age, children still do not possess full control of their movements.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.2
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• pp.167-174
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• 2010

In this study, the optimal position for the backrest pivot of an office chair was investigated by evaluating its performance in terms of the lumbar support and sliding distance of the back from the backrest during tilting motions. The simulation was performed using a mathematical model, which included a human body and a chair. Forty-two backrest pivot points were selected on the sagittal plane around the hip joint of a sitting model. A motion analysis study was also performed using a prototype of an office chair (A-type) with a backrest pivot located on the hip joint of a normal Korean model and a typical office chair (B-type) with its pivot located under the seat. The simulation results showed that both the lordosis angle and the slide distance of the back were minimized when the backrest pivot was positioned close to the hip joint. The experimental results showed that the slide distance and gap between the sitter's lumbar and the backrest was smaller with the A-type than the B-type. Based on the simulation and experimental results, it can be concluded that the backrest can support the sitter's lumbar area more effectively as the pivot position for reclining approaches closer to the hip joint. In this position, the sitter can maintain a comfortable and healthy sitting posture. This paper presents the methods and guidelines for designing an office chair with ergonomic considerations.

• Journal of Information Processing Systems
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• v.12 no.2
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• pp.196-213
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• 2016

System Architecture Evolution (SAE) with Long Term Evolution (LTE) has been used as the key technology for the next generation mobile networks. To support mobility in the LTE/SAE-based mobile networks, the Proxy Mobile IPv6 (PMIP), in which the Mobile Access Gateway (MAG) of the PMIP is deployed at the Serving Gateway (S-GW) of LTE/SAE and the Local Mobility Anchor (LMA) of PMIP is employed at the PDN Gateway (P-GW) of LTE/SAE, is being considered. In the meantime, the Host Identity Protocol (HIP) and the Locator Identifier Separation Protocol (LISP) have recently been proposed with the identifier-locator separation principle, and they can be used for mobility management over the global-scale networks. In this paper, we discuss how to provide the inter-domain mobility management over PMIP-based LTE/SAE networks by investigating three possible scenarios: mobile IP with PMIP (denoted by MIP-PMIP-LTE/SAE), HIP with PMIP (denoted by HIP-PMIP-LTE/SAE), and LISP with PMIP (denoted by LISP-PMIP-LTE/SAE). For performance analysis of the candidate inter-domain mobility management schemes, we analyzed the traffic overhead at a central agent and the total transmission delay required for control and data packet delivery. From the numerical results, we can see that HIP-PMIP-LTE/SAE and LISP-PMIP-LTE/SAE are preferred to MIP-PMIP-LTE/SAE in terms of traffic overhead; whereas, LISP-PMIP-LTE/SAE is preferred to HIP-PMIP-LTE/SAE and MIP-PMIP-LTE/SAE in the viewpoint of total transmission delay.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.285-292
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• 2007

This study was developed the metallic plate for fixation in the femur fracture for the orthopedic region and rigid fixation with plates has a firm place in fracture treatment. Most plates can be used for rigid as well as biological and dynamical fracture fixation. The device's designation and sizing has a specific with bending structural stiffness and strength, known meaning that is reliable regardless of the plate by the short type and long type. Short plate have a wrapping of femur and long plate have to preserve a pole of femur. The bending strength of the curved metallic long plate has to evaluate a 11,000N and The bending strength of the curved metallic short plate has to evaluate a 6,525N. The tensile stress through to press a plate is $1573N/m^2\;and\;1539N/m^2$. The device can be used to support Revision case of Hip Implant and to use a case of Hip screw compression of Hip Neck Fracture.

• Journal of the Ergonomics Society of Korea
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• v.29 no.3
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• pp.279-286
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• 2010

The purpose of this study was to compare the electromyographic(EMG) activities of trunk and hip muscles between right and left sides while subjects performed prolonged manual task in asymmetric and symmetric weight-bearing posture. Fifteen healthy male college students were recruited for this study. The subjects were asked to perform bimanual upper extremity task for 6 minutes in two different standing postures. In the symmetric weight-bearing posture, the subjects were standing with evenly distributed body weights to both legs. In the asymmetric weight-bearing posture, the subjects distributed about 90% of their body weight onto their preferred(supporting) leg and 10% of their body weight onto the opposite leg while they were standing. EMG activities of the right and left internal oblique, erector spinae, gluteus maximus, and gluteus medius were measured and normalized as % MVIC. Then the EMG data were statistically analyzed using paired t-tests. The EMG activities of all measured muscles were not significantly different between the right and left side in the symmetrical weight-bearing posture(p>0.05). However, the EMG of the supporting side internal oblique was significantly lower than the opposite side(p<0.05), and the EMG of the erector spinae, gluteus maximus, and gluteus medius were significantly greater on the supporting side(p<0.05). The results of this study support that unbalanced use of right and left muscle possibly causes the changes in muscle length which results in asymmetry of trunk and hip muscles. Furthermore, the uneven weight support onto right and left legs will cause a distortion of viscoelastic ligaments around hip and sacroiliac joints in the long run. Further studies to determine the effect of various manual tasks on the trunk and hip muscles as well as the effect of asymmetrical weight-bearing standing posture on hip and back muscle fatigue may be required.

• Physical Therapy Korea
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• v.9 no.3
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• pp.23-37
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• 2002

This study examined the muscle recruitment order during extension of the hip joint in normal subjects, and evaluated whether the external support obtained from wearing a lumbosacral corset had an effect on muscle recruitment leading to increased lumbar stability. The subjects were 40 normal adults (32 male, 8 female) with no history of low back pain and no pathological findings in the nervous or musculoskeletal systems. All subjects extended their hip joints under 3 positions (prone, sidelying, standing). During extension, the onsets of contraction of the rectus abdominis, gluteus maximus, and semitendinosus muscles were measured. Electromyographic activity was measured using a surface electrode, and the muscle contraction onset time was designated as the point exceeding a threshold of 25 ms, using a mean plus twice of the standard deviation. To compare the average order of muscle contraction onset time, a Freedman two-way analysis of variance by ranks was used. The relative difference between muscle contraction onset time wearing and not wearing a lumbosacral corset was measured using a paired t-test. A difference in the average muscle contraction onset order for the rectus abdominis, gluteus maximus, and semitendinosus muscles was observed (p<.05) among three positions. However, wearing a lumbosacral corset did not. change the contraction order. In addition, wearing a lumbosacral corset produced a significant difference (p<.05) in the relative onset time between the rectus abdominis and gluteus maximus in the standing position, but no difference was observed for the other muscles or positions. In the future, patients suffering from low back pain should be compared with normal subjects to determine the effectiveness of a lumbosacral corset in changing muscle recruitment order.

• Fire Science and Engineering
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• v.34 no.2
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• pp.103-109
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• 2020

This study aims to investigate the improvement in basic CPR quality on the basis of the hip joint angle of the rescuer among students in the Department of Emergency Medical Technology who completed a basic CPR curriculum. In this study, we carried out a comparative analysis using SimPad SkillReporter and Resusci Anne® QCPR® to measure the quality of CPR (depth of chest compressions, full relaxation, compression speed, and more) on the basis of the rescuer's hip joint angle in accordance with the 2015 AHA Guidelines and conducted chest compressions and CPR 5 times in a 30:2 ratio. It was found that maintenance of the rescuer's hip joint angle at 90 degrees while compressing and relaxing the chest made a statistically significant difference in both the experimental and control groups. Moreover, this indicated that the closer the hip joint angle was to 90 degrees, the better was the quality of basic CPR. However, there was no significant difference in the hip joint angle, degree of CPR, depth of chest compressions, chest compression speed, chest compression and relaxation percentages (%), accuracy of chest compressions, hands-off time during CPR, and percentage of chest compression time (p > 0.05). Maintaining the hip joint angle at 90 degrees for basic CPR was not significantly different from not maintaining this angle. Nonetheless, good results have been obtained at moderate depth and 100% recoil. Therefore, good outcome and high-quality CPR are expected.

• The Journal of Korean Physical Therapy
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• v.18 no.4
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• pp.27-40
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• 2006

Purpose: This study was to investigate the effect of an arm sling on gait with hemiparesis. Methods: Fifteen patients(8 male, 7 female) with hemiparesis participated in this study and walked self-selected speed over 10m walkway, randomly without arm sling, with Single strap hemisling and Rolyan humeral cuff sling. It were filmed by 5 video camera and used with 3-dimensional motion analyzer system. The following gait variables were analyzed: temporo-spatial parameters, kinematic parameters. Results: In the comparison of temporo-spatial parameters each trial, walking velocity and single support time on affected side was significantly increased and step length on affected side, step length asymmetry ratio, single support time asymmetry ratio was significantly decreased in the Single strap hemisling and Rolyan humeral cuff sling. In the comparison of kinematic parameters each trial, maximal angle of the hip flexion on affected side was significantly increased in the Single strap hemisling and Rolyan humeral cuff sling and maximal angle of the knee flexion on affected side was significantly increased in the Rolyan humeral cuff sling and maximal angle of the ankle dorsiflexion on affected side was significantly increased in the Single strap hemisling. Conclusion: An arm sling improved walking velocity and decreased asymmetry and increased maximal angle of hip, knee, ankle flexion on affected side with hemiparesis caused by stroke.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.71-78
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• 1997

Kinematic and kinetic studies were performed to investigate the walking characteristics on a treadmill with various slopes at the same speed of 1.25m/sec. Six different slopes of the treadmill were selected . -4%(-$2.3^{\circ}$), 0%($0^{\circ}$), 5%($2.9^{\circ}$), 10%($5.7^{\circ}$), 15%($8.6^{\circ}$), and 20%($11.3^{\circ}$). With increased slopes of the treadmill, both hip and knee flexion angles significantly increased at initial contact, and the maximum hip flexion during swing phase and the maximum knee flexion during stance phase also significantly increased Ankle dorsiflexion angle at initial contact and the maximum dorsiflexion increased with increased slopes. However, the maximum plantarflexion in early swing was slightly reduced with increased slopes. Hip extension in late stance and the maximum knee flexion in early swing was not changed sigilificantly with increased slopes. As for the vertical ground reaction force, compared to the yond level walking, both the first and the second peak forces increased, but the mid-support force decreased.