• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.437-445
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• 2010

This study was aimed at comparing selected joint angles at the golf address stance by categorizing three different body types. 43 elite male golfers were selected and 9 of them turned out to be the ectoderm while 24 of them to be the mesoderm. The remaining 10 subjects were the endoderm. The measurement was carried out at the address stance with the number 7 iron and the driver. The result showed that the angle of trunk flexion did not different among body types. The trunk tilting angle became more inclined to the right side, which confirmed the guidelines from most of golf lesson books, for bigger people since they tended to put more weight on the right foot. The angle of both knees showed similar but the right knee was bent more than the left knee. The target direction and body alignment faced more to the left side than the target spot because of the influence of open stance and natural aiming position. It seems that pelvis and knees turned a little bit more to the right side than the target direction in order to maintain the parallel. Overall, significant differences among body types were found at the trunk tilting angle and pelvis-target alignment and golf address configuration can be differentiate by these factors.

• Korean Journal of Applied Biomechanics
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• v.24 no.2
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• pp.121-129
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• 2014

The purpose of this study was to investigate the effect of the toe headings on the biomechanics of knee joint in drop landing in an attempt to find the potential risk of non-contact anterior cruciate ligament (ACL) injury. Seventeen male college students ($20.5{\pm}1.1$ yrs; $175.2{\pm}6.4$ cm; $68.8{\pm}5.8$ kg), having no neuromuscular injury within an year, participated in this study. Three different toe headings such as toe-in (TI), neutral (N), and toe-out (TO) positions were tested. Motion capturing system consisting of eight high speed cameras and two force platforms were used to collect three-dimensional motion data and ground reaction force data during landing. Results indicated joint angles and peak joint moments were significantly affected by the toe headings. TI position produced larger valgus angle due to reduce knee distance in addition to higher flexion and valgus moment than other positions, which was somewhat vulnerable to the potential risk of non-contact ACL injury. TO position caused the largest internal rotation angle with smaller joint moments. Therefore, it is recommended that athletes need to land on the ground with neutral toe-heading position as possible in order to minimize the potential risk of non-contact ACL injury.

• Korean Journal of Applied Biomechanics
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• v.24 no.4
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• pp.435-443
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• 2014

The purposes of this study was to investigate the physical compensation for gait on induced equinus in normal subjects. Ten subjects were participate in the experiment (age: $23.8{\pm}2.8yrs$, height: $177.3{\pm}4.3cm$, weight: $70.8{\pm}4.6kg$). The study method adopted 3D analysis with six cameras and ground reaction force with two force-plate. Induced equinus were classify as gait pattern on unilateral and bilateral equinus. The results were as follows; In displacement of COM, medio-lateral and anterior-posterior COM were no significant, but in vertical COM, unilateral equinus gait was higher than bilateral equinus gait. In displacement hip joint, left hip joint was more extended in FC1 and FC2 during unilateral equinus gait. In displacement knee joint, left knee joint was more extended in FC2, right knee joint was more extended in all event during unilateral equinus gait. In trunk tilt, unilateral equinus gait was more forward tilt in TO1 and TO2. ROM of each joint was no significant. In Displacement of pelvic tilt angle, X axis of unilateral equinus gait was more increase than bilateral equinus gait at FC2, TO2 and MS2. Y axis of unilateral equinus gait was more increase than bilateral equinus gait at MS1, FC2 and MS2. Z axis was no significant in both equinus gait. In GRF, right Fx and Fy were no significant in both equinus gait, Fz was more bigger vertical force in bilateral equinus gait. Left Fx was more bigger internal force in unilateral equinus gait, Fy and Fz were no significant in both equinus gait.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.11-21
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• 2008

The purpose of this study was to investigate the most optimum way of performing the bandal chagi during Taekwondo Kyorugi competition. By analyzing the EMG data and the kinematic data it was hoped that scientific data would be provided to instructors and players about the optimization of the Bandal Chagi. The results of the analysis are as follows: During competition while performing the Bandal Chagi the most important factors that affect the impact point are the range of motions of the upper body hyper extension and knee joints. Through the measurement of the muscles EMG activity of a well performed Bandal Chagi with the right leg it was observed that the left side erector spinae muscle was highly activated and so it was concluded that this muscle should be trained to improve the performance of the Bandal Chagi. Likewise it was observed that for the right side of the abdominal muscle's EMG there was a high activity level and thus showed that there was a large contribution of this muscle for the optimum performance of the Bandal Chagi.

• Korean Journal of Applied Biomechanics
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• v.18 no.3
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• pp.51-59
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• 2008

The objective of this study is to kinematically analyze forehand & backhand strokes of abscission handicap wheelchair table tennis athletes. The participant of this study were picked out of national athletes who have abscission handicap. Forehand stroke movement was expected to show a throw like motion. However, external rotation and internal rotation of the right arm created a backswing and an impact. Backhand stroke was expected to show a push like motion, and as expected, proximal part of the body didn't participate in the stroke motion, but the distal part, the right arm, rotated internally to backswing and external rotated to impact to form a push like motion. Forehand swing was expected to show throw like motion according to the Link Segmental System principle. However, abscission handicap athlete didn't show clear linking structure connecting proximal and distal parts. Successful strokes were dependant only on the angle of arm rotation.

• Korean Journal of Applied Biomechanics
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• v.17 no.3
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• pp.11-21
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• 2007

The purpose of this study was to examine the differences of kinematics and muscle activities depending on the changes of angle approaching balls during backhand drive in squash. The results are as follows. Stride time took the longest at AD2 and step lengths were the biggest at AD1 of left foot contact and right foot contact and AD2 of impact and follow-through. The center of gravity and the speed of racket head were the highest at AD3 and at AD2. Angle of shoulder joint were the biggest at AD1 of left foot contact, right foot contact and impact and AD3 of follow-through. Angle of elbow joint were the biggest at AD3 of left foot contact, right foot contact and follow-through and AD2 of impact. Angle of pelvis joint were the biggest at AD2 of left foot contact, AD1 of right foot contact and AD3 of impact and follow-through. Angle of knee joint were the biggest at AD2 of left foot contact, AD1 of right foot contact and AD3 of impact and follow-through. Angle of ankle joint were the biggest at AD1 of left foot contact and AD3 of right foot contact, impact and follow-through. According to the analysis results of triceps brachii, latissimus dorsi, brachioradialis muscle and flexor carpi ulnaris muscle activities were high at AD1 of all phases. Analysis results of vastus lateralis, vastus medialis, tibialis anterior and gastrocnemius medial muscle activities were high at AD2 of phase1 and phase3. Those of vastus lateralis, vastus medialis and tibialis anterior, gastrocnemius medial were high at AD3 of Phase 2 and AD1 of phase2.

• Journal of Biomedical Engineering Research
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• v.24 no.6 s.81
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• pp.495-500
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• 2003

The purpose of this investigation was to study the kinematics of joints between the foot segments based on computer graphic model during the stance? phase of walking. In the model, all joints were assumed to act as monocentric. single degree of freedom hinge joints. The motion of foot was captured by a video collection system using four cameras. The model fitted in an individual subject was simulated with this motion data. The range of motion of the first tarsometatarsal joint was $-8^{\circ}\;\~\;-13^{\circ}$, and the first metatarsophanlangeal joint was $-13^{\circ}\;\~\;-48^{\circ}$. The kinematic data of tarsometatarsal joint and metatarsophanlangeal joint were similar to the previous data. Therefore, our method based on the graphical computer model is considered useful.

• Korean Journal of Remote Sensing
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• v.15 no.4
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• pp.289-295
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• 1999

Space Physics Sensor (SPS) on-board the KOMPSAT-1 consists of the High Energy Particle Detector (HEPD) and the Ionospheric Measurement Sensor (IMS). The HEPD is to characterize the low altitude high energy particle environment and the effects on the microelectronics due to these high energy particles. It is composed of four sensors: Proton and Electron Spectrometer(PES), Linear Energy Transfer Spectrometer (LET), Total Dose Monitor (TDM), and Single Event Monitor (SEM). 35 MeV proton beam from the medical KCCH cyclotron, at Korea Cancer Center Hospital in Seoul, is used to calibrate the PES. Primary proton beam of 35MeV scattered by polypropylene target is converted to various energy protons according to the elastic collision kinematics. In this calibration, the threshold level of the proton in the PES can be determined and the energy ranges of PES channels are also calibrated.

• Smart Structures and Systems
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• v.9 no.6
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• pp.505-534
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• 2012

The present work deals with second order statistics of post buckling response of piezoelectric laminated composite cylindrical shell panel subjected to hygro-thermo-electro-mechanical loading with random system properties. System parameters such as the material properties, thermal expansion coefficients and lamina plate thickness are assumed to be independent of the temperature and electric field and modeled as random variables. The piezoelectric material is used in the forms of layers surface bonded on the layers of laminated composite shell panel. The mathematical formulation is based on higher order shear deformation shell theory (HSDT) with von-Karman nonlinear kinematics. A efficient $C^0$ nonlinear finite element method based on direct iterative procedure in conjunction with a first order perturbation approach (FOPT) is developed for the implementation of the proposed problems in random environment and is employed to evaluate the second order statistics (mean and variance) of the post buckling load of piezoelectric laminated cylindrical shell panel. Typical numerical results are presented to examine the effect of various environmental conditions, amplitude ratios, electrical voltages, panel side to thickness ratios, aspect ratios, boundary conditions, curvature to side ratios, lamination schemes and types of loadings with random system properties. It is observed that the piezoelectric effect has a significant influence on the stochastic post buckling response of composite shell panel under various loading conditions and some new results are presented to demonstrate the applications of present work. The results obtained using the present solution approach is validated with those results available in the literature and also with independent Monte Carlo Simulation (MCS).

• Annals of Rehabilitation Medicine
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• v.42 no.6
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• pp.872-883
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• 2018

Objective To replace camera-based three-dimensional motion analyzers which are widely used to analyze body movements and gait but are also costly and require a large dedicated space, this study evaluates the validity and reliability of inertial measurement unit (IMU)-based systems by analyzing their spatio-temporal and kinematic measurement parameters. Methods The investigation was conducted in three separate hospitals with three healthy participants. IMUs were attached to the abdomen as well as the thigh, shank, and foot of both legs of each participant. Each participant then completed a 10-m gait course 10 times. During each gait cycle, the hips, knees, and ankle joints were observed from the sagittal, frontal, and transverse planes. The experiments were conducted with both a camera-based system and an IMU-based system. The measured gait analysis data were evaluated for validity and reliability using root mean square error (RMSE) and intraclass correlation coefficient (ICC) analyses. Results The differences between the RMSE values of the two systems determined through kinematic parameters ranged from a minimum of 1.83 to a maximum of 3.98 with a tolerance close to 1%. The results of this study also confirmed the reliability of the IMU-based system, and all of the variables showed a statistically high ICC. Conclusion These results confirmed that IMU-based systems can reliably replace camera-based systems for clinical body motion and gait analyses.