• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.8
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• pp.2101-2112
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• 1994

A two-dimensional biomechanical model was developed in order to calculated the lower extremity kinematics and kinetics during level walking. This model consists of three segments : the thigh, calf, and foot. Each segment was assumed to be a rigid body ; its motion to be planar in the sagittal plane. Five young males were involved in the gait experiment and their anthropometric data were measured for the calculation of segmental masses and moments of inertial. Six markers were used to obtain the kinematic data of the right lower extremity for at least three trials of walking at 1.0m/s, and simultaneously a Kistler force plate was used to obtain the foot-floor reaction data. Based on the experimental data acquired for the stance phase of the right foot, calculated vertical joint forces reached up to 0.91, 1.05, and 1.11 BW(body weight) at the hip, the knee, the ankle joints, respectively. The flexion-extension moments reached up to 69.7, 52.3, and 98.8 Nm in magnitude at the corresponding three joints. It was found that the calculated joint loadings of a subject were statistically the same for all his three trials, but not the same for all five subjects involved in the gait study.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.792-795
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• 2007

To quantify irregular body motions the time series analysis was applied to the gait study. The motions obtained from gait experiment are complex to exhibit nonlinear behaviors. The purpose of this study is to measure quantitatively the characteristics of the major six joints of the body during walking. The gait experiments were carried out for eighteen young males walking on a motor driven treadmill. Joint motions were captured using eight video cameras, and then three dimensional kinematics of the neck and the upper and lower extremities were computed by KWON 3D motion analysis software. The largest Lyapunov exponent was calculated from the time series to quantify stabilities of each joint. The results provides a data set of nonlinear dynamic characteristics for six joints engaged in normal walking.

• Journal of Biomedical Engineering Research
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• v.31 no.1
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• pp.74-80
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• 2010

This paper presents the three dimensional gait analysis of the patients with osteoarticular knee allograft reconstruction. The gait analysis has been performed in some medical fields such as orthopedics and neurosurgery for the purpose of the rehabilitation of patients. However, to the author's knowledge, the analysis of gait for the patients with osteoarticular knee allograft reconstruction caused by tumor has not been reported. In this work, In this work, we confirmed the validity of this method by analyzing 50 samples per one gait cycle obtained from each of 3 patients and 3 normal persons. The motion capture was performed using six infrared cameras. The symmetry and stability of the gait patterns are investigated (patients' r=0.39, p<0.05, normal persons' r=0.65, p<0.05) respectively using the correlation coefficients and the standard deviations of the joint angles of the left and right legs. It also would be applied to the comparison analysis where artificial knee joint is transplanted.

• The Journal of Korean Physical Therapy
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• v.26 no.2
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• pp.74-81
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• 2014

Purpose: The purpose of this study is to compare kinematics and kinetics on the knee joint between stair gait with unstable shoes and barefoot in healthy adult women. Methods: Seventeen healthy adult women were recruited for this study. The subjects performed stair ascent and descent with unstable shoes and barefoot. The experiment was repeated three times for each stair gait with unstable shoes and barefoot. Measurement and analysis of the movements of the knee joint were performed using a three-dimensional analysis system. Results: Statistically significant differences in the knee muscle force of semimembranosus, biceps femoris-long head, biceps femoris-short head and sartorius, patellar ligament, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair ascent. Statistically significant differences in the knee muscle force of sartorius, rectus femoris, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair descent. Statistically significant differences in the knee flexor moment of semitendinosus, biceps femoris-long head, biceps femoris-short head, sartorius, rectus femoris, vastus intermedialis, medial gastrocnemius, and lateral gastrocnemius were observed between unstable shoes and barefoot gait during stair ascent. Conclusion: Therefore, wearing unstable shoes during stair gait in daily life is considered to influence knee joint kinematics and kinetics due to the unstable shoes, and thus suggest the possibility that reducing the risks of pain, and knee osteoarthritis, stabilizing the knee joint caused by changes in the loading of the knee joint.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.431-437
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• 2010

The purpose of this study is to compute the ground reaction forces during gait in the absence of force plates. The difficulties in using force plates for hemiparetic patients inspired us to initiate this study. Level-walking experiments were performed using a three-dimensional motion analysis system with synchronized force plates. Kinematic data were obtained from the three-dimensional trajectories of reflective markers. Gait events were also detected from the kinematic data. The human body was modeled as 13 rigid segments. The mass and the center of mass of each segment were determined from anthropometric data. Vertical ground-reaction forces obtained from the kinematic data were in good agreement with those obtained using the force plate. The computed and measured values of anterior and lateral ground reaction showed similar tendencies. The computation results can be used as the basic data for inverse dynamic analysis.

• The Journal of Korean Physical Therapy
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• v.31 no.5
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• pp.273-278
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• 2019

Purpose: The purpose of this study was to investigate the effects of three-dimensional virtual reality horse riding simulator training using a head-mounted display on gait and balance in children with cerebral palsy. Methods: Ten children with cerebral palsy were randomly assigned to the horse riding simulator (HRS) group (n=5) or the horse riding simulator with virtual reality (HRSVR) group (n=5). To evaluate balance, center of gravity (COG) sway velocity and total sway distance of each group were assessed using the Wii balance board, and gait speed and stride length of each group were assessed using a gait analysis system. Results: Intra-group comparisons between pre- and post-intervention measures revealed that there were significant changes in all gait and balance variables such as stride length, gait velocity, COG sway velocity and COG sway distance in the HRSVR group (p<0.05). In the HRS group, there were significant changes in all variables except stride length (p<0.05). In addition, inter-group comparisons showed significant differences between the two groups in stride length, gait velocity and COG sway distance except COG sway velocity (p<0.05). Conclusion: The findings of this study suggest that horse riding simulator training combined with 3D virtual reality can be a new positive therapeutic approach for improving functional performance in children with cerebral palsy.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.129-137
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• 2010

The purpose of this study is to investigate the effect of a 12-week aquatic exercise on obstacle gait in older women. Originally, 20 healthy female elderly participated this study but 12 of them completed the program. All participants were trained in the aquatic exercise program by an authorized trainer. They had come to the authors' lab three times during training period(0, 6, 12 weeks) and performed obstacle gait with three different height(0, 30, and 50% of leg length). After performed 3-Dimensional motion analysis following results were found. (1) For the CV, MVHC, TC, HC, statistically significances were shown in obstacle height. Although significant training effects were not shown, all variables showed typical patterns and it was considered as efficient motion to overcome the height obstacles. (2) The anterior-posterior and vertical GRF of support leg during support phase were revealed in height effect but in training one. However, differences between Peak 1 and Peak 2 in vertical GRF increased as training period increased. (3) Knee and hip resultant joint moments were affected by training but ankle resultant moments remained unchanged.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.4 s.247
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• pp.435-441
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• 2006

The anterior cruciate ligament(ACL) is an important stabilizer of knee joint. The ACL injury of knee is common and a serious ACL injury leads to ligament reconstruction surgery. Gait analysis is essential to identify knee condition of patients who display abnormal gait. The purpose of this study is to evaluate and classify knee condition of ACL deficient patients using a nonlinear dynamic method. The nonlinear method focuses on understanding how variations in the gait pattern change over time. The experiments were carried out for 17 subjects(l2 healthy subjects and five subjects with unilateral deficiency) walking on a motorized treadmill for 100 seconds. Three dimensional kinematics of the lower extremity were collected by using four cameras and KWON 3D motion analysis system. The largest Lyapunov exponent calculated from knee joint flexion-extension time series was used to quantify knee stability. The results revealed the difference between healthy subjects and patients. The deficient knee was significantly unstable compared with the contralateral knee. This study suggests an evaluation scheme of the severity of injury and the level of recovery. The proposed Lyapunov exponent can be used in rehabilitation and diagnosis of recoverable patients.

• Physical Therapy Korea
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• v.9 no.3
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• pp.39-46
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• 2002

In this study, vertical acceleration of center of mass was observed along normal gait phases in 9 healthy male volunteers (aged $25.7{\pm}2.18$). The developed wireless accelerometric device was attached on the intervertebral space between L3 and L4 using a semi-elastic waist belt. A three-dimensional motion analysis system, synchronized with the accelerometry, was used for detecting gait phases. There was no significant correlation between the body weight and the acceleration. The first peak curve covered loading response phase. The second downward peak point was matched accurately with the opposite toe-off. In mid-stance and terminal stance, the acceleration curve highly resembled the vertical ground reaction force curve. There was no significant difference in timing between the final upward peak point and the initial contact. Therefore, the developed accelerometry system would be helpful in determining determine temporal gait pattems in patients with gait disorders.

• Physical Therapy Korea
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• v.9 no.3
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• pp.77-91
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• 2002

Asymmetrical stance posture, balance, and gait disturbance are common problems in hemiplegic patients. Posterior leaf springs (PLS) are frequently prescribed to correct these problems. Recently, anterior leaf springs (ALS) have also been prescribed, but only limited studies have been performed to investigate the effects of ALS. The purpose of this study was to compare the effects of three conditions, i.e., wearing an ALS, wearing a PLS, and not wearing an AFO (ankle foot orthosis),: on 1) the distribution of weight bearing on the affected side, 2) standing balance, and 3) the gait patterns of hemiplegic patients. Eleven hemiplegic patients (10 men and 1 woman) participated in this study. The data were analyzed by the Friedman test. The results were as follows: 1) More weight bearing on the affected leg was observed in the ALS and PLS conditions than in the condition without an AFO. No significant difference between the ALS and PLS conditions was found. 2) There were statistically significant differences in the composite equilibrium scores (CES) among the three conditions. The CES in the PLS condition was significantly higher than in the ALS condition or the condition without an AFO. 3) Gait patterns improved significantly in the ALS and PLS conditions. No statistically significant difference between the ALS and PLS conditions was found. These results suggest that both ALS and PLS effectively improve the distribution of weight bearing on the affected side, standing balance, and gait patterns of hemiplegic patients. Further study using three-dimensional kinematic analysis and dynamic electromyography is needed to support these findings.