• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.11-18
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• 2014

The purposes of this study were to analyze the kinematics and electromyographic variables of the upper extremity for the backhand clear motion according to the type of hitting in badminton. Seven elite male university players were selected as the subjects. Four digital video cameras and Noraxon Telemyo 2400 were used to collect the 3D kinematics and electromyographic data. The results were as follows: 1) in the phase of impact, the time of motion for the overhead backhand clear was the longest, 2) in the event of impact, the distance of step toward X direction was the longest and the distance of step toward Y direction was the shortest for the overhead backhand clear, 3) in the event of backswing, the rotation angles of shoulder and pelvis and the flexion angle of shoulder for the overhead backhand clear were the biggest, 4) the maximum flexion angular velocity of shoulder and the maximum extension angular velocity of elbow for the overhead backhand clear were the biggest, and 5) in the phase of impact, mean EMG of the wrist flexor, triceps, and trapezius muscle for the overhead backhand clear was bigger than that for the underhand stroke and in the phase of follow-through, mean EMG of the wrist flexor and extensor, biceps, triceps, and trapezius muscle for the overhead backhand clear was the biggest.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.27-46
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• 2003

The purposes of this study were to determine the functions of actions of the limbs during each of the three support phases of the triple jump and their relationships with the performance of the triple jump. Four elite male triple jumpers were participated as subjects. The statistical analyses used were the Pearson product moment correlation coefficient for establishing relationships and simple regression analyses to determine and compare the relationships between the change of the horizontal velocity and the change of the vertical velocity during different support phases. A level of significance at p<.05 was set. The actions of the arms were responsible for about 25%, 25%, and 30% of the decrease in the horizontal velocity of the whole body center of gravity during the support phases of the hop, step, and jump, respectively. The change in the velocities of the whole body center of gravity due to the actions of the free limbs were significantly related with the whole body center of gravity during each support phase. The action of the support leg was associated with the decrease in the horizontal velocity and the increase in the vertical velocity of the whole body center of gravity during each support phase.

• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.57-65
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• 2010

Korean traditional martial arts Taekkyon has a unique stepping method, Poombalbki. The purpose of this study was to investigate kinematic factors and ground reaction forces on two types of Poombalbki, one of which use knee bending and the other use chiefly hip bending. Six male taekkyoners who are the students of Y University participated in this study. Positions and velocities of CoM, the elapsed times of each phase, angles and angular velocities of low limb joints, and GRFs were analyzed for this study. The results were as follows; CoMs of whole body, trunk, and head were more posteriorly positioned in performing hip bending Poombalbki than knee bending one. Horizontal velocities of those were slower in performing hip bending Poombalbki. A player stayed more shortly within range of his opponent in performing hip bending Poombalbki. The vertical and horizontal components of GRF of forward-stepping foot were smaller in performing hip bending Poombalbki(p<.05). In conclusion hip bending is useful strategy, because A player is farther from his opponent, he stayed more shortly within range of his opponent, and the smaller weight is loaded on his front foot in performing hip bending Poombalbki than knee bending one.

• Korean Journal of Applied Biomechanics
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• v.30 no.3
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• pp.217-223
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• 2020

Objective: The purpose of this study was to analyze the effect of postural sway on the kinematic variables of the putter head during golf putting and to provide information to the importance of postural sway control in the putting stroke for novice golfers. Method: The center of pressure (CoP) and Kinematics variables of the putter head were calculated during 2 m flat golf putting using 8 motion capture cameras (250 Hz) and 2 force plate (1,000 Hz). SPSS 24.0 was used to perform Pearson's correlation coefficient and simple regression analysis, and the statistically significance level was set to .05. Results: As a result of analyzing the correlation between CoP variables and the putter head rotation angle, the CoP moving length, CoP moving range (ML direction), and CoP moving velocity (ML direction) showed a positive correlation with the putter head rotation angle (yaw axis) and were statistically significant. Conclusion: Therefore, In order to perform the accurate putting stroke maintaining the ball's directionality, it is determined that it is important to control posture sway in the ML directions by minimizing the movement and velocity of the CoP.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.1-7
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• 2012

The purpose of this study was to investigate the pattern change of throwing in baseball after 15 weeks of participation in baseball class, by examining ball speed, trunk and upper body angles. The comparison was with 6 university students that haven't had any experience in baseball. 8 infra red cameras and 2 force platforms were used to collect the data. First, there was an increase in the speed of the ball after the class. Second, there was no significant difference in the allocated phases during the throw before and after class. Third, the release point was lower and more in front. Forth, there was an increase in the knee flexion at the left foot landing and release point. Finally, there was an increase in the maximum shoulder external rotation and pelvis angle. It is recommended that the coordination between the segments should be investigated to improve our understanding of the learning of throwing in future research.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.131-142
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• 2005

This study was investigated the stability of the AK amputee gait through analysing the variability on kinematic variables between the sound leg and the prosthetic limb. The one male, AK amputee who could walk for himself with his prosthetic limb was participated in this study. Six cameras of the MCU 240 and the QTM(Qualisys Track Manager) software were used for data collecting in this study. The relative angle of both segments was the difference between the absolute angle of the distal segment and the absolute angle of the proximal segment. The coupling angles between the prosthetic limb and the sound leg were caculated on the thigh Flexion/Extension in relative to the shank Flexion/Extension and the shank Flexion/Extension n relative to the foot Flexion/Extension. In order to evaluate the variability of segment and joint angle, C.V. was used, and to evaluate the variability for coupling angles, the Relative motion calculated by vector coding method of the continuous methods was used. As stated, the gait pattern of the prosthetic limb was almost similar gait pattern of the sound leg, but the prosthetic limb showed that the gait pattern of the sound leg and the prosthetic limb were not stable against the sound leg.

• Korean Journal of Applied Biomechanics
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• v.20 no.4
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• pp.407-414
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• 2010

The purpose of this study was to evaluate the effect of taping-tape with or without using spiral taping on vertical jump. The subjects for this study were about 20 years old healthy male college students without muscloskeletal diseases. Data for EMG activity and Ground Reaction Force(GRF) were estimated at three knee angles(i.e., 45, 90 & full degree). As a result, there was no statistical significance in max GRF at 90 and full degree regardless of spiral taping-tape. On the other hand, statistical significance was found when vertically jumping at 45 degree knee angle(p<.05). All the data for EMG activity at the three knee angles were not statistically significant, but there was a trend for a decrease in average EMG activity in elector spinae & Medial gastrocnemius at 90 degree knee angle. Based on these data, initial flexor action of knee was stabilized with spiral taping-tape when vertically jumping, resulting in improved muscular activity in Medial gastrocnemius. In conclusion, taping technique for jumping ability associated muscles like quadriceps is also required to develop.

• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.71-82
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• 2022

The purpose of this study is to investigate the effect of leadership behavioral patterns on athletic stress in Chinese badminton athletes. The subject of this study was nomadic sampling of 203 Chinese badminton players with or without experience in the national team. The results obtained by distributing a total of 203 questionnaires and processing the data according to the purpose of the study using 170 copies excluding unfaithful data among them are as follows. First, it appears that the leader leadership type and exercise stress according to demographic variables have a significant effect. Second, as a result of correlation analysis, there was a positive correlation between exercise stress and its sub-factors. A negative correlation was found with independent variables such as leadership behavioral style, democratic behavior, social support behavior, and positive reward behavior, and a positive correlation was found with training, directive behavior, and authoritative behavior. Second, it was found that exercise stress had a significant effect according to the type of leader leadership behavior.

• Korean Journal of Psychosomatic Medicine
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• v.22 no.1
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• pp.3-12
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• 2014

Objectives : We aimed to explore the relationship among fatigue and perceived stress, depressive mood in the working population. We also examined associations with demographic and life style factors and investigated the effect of individual coping skills on these associations. Methods : Fatigue Severity Scale(FSS), Perceived Stress Scale(PSS), Brief Encounter Psychosocial Instrument - Korean version(BEPSI-K), Beck Depression Inventory(BDI), Stress Coping Skill Questionnaire were administered to 621 civil servants. All of above and other demographic factors are self-administered questionnaire survey and this study is cross sectional. Results : Mean FSS score was 3.04 which was lower than 3.22, the severity cut off score. FSS, PSS, BEPSI-K, BDI were all higher in female. Subjects with active coping skills showed relatively low fatigue, perceived stress, depressive mood than those with passive coping skills. Logistic regression analyses indicated that the PSS, BDI, BEPSI-K in working population increase the risk of fatigue and regular exercise lowers the risk. Conclusions : Adults who were afflicted by stress, experienced depressive mood or were physically inactive were at much higher risk of feeling fatigue. Since no other large data sets are available for fatigue, the results from this study could serve a very useful purpose, to furnish a basis for comparison with future research results based on more complete data.

• Korean Journal of Applied Biomechanics
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• v.19 no.1
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• pp.167-177
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• 2009

The purpose of this study was to investigate effect of golf shoe design on kinematic variables during golf swing. Five professional male golfers with shoe size 270mm were recruited for the study. Swing motion was collected using 8 high speed camera motion analysis at a sampling of 180Hz. Kinematic variables were calculated by EVaRT 4.2 software. Driver swing was divided into four events; El(adress), E2(top), E3(impact) and E4(finish). Time, peak velocity, velocity of center of mass, velocity of the foot and ankle angle during Phase 1(El-E2), Phase 2(E2-E3), and Phase 3(E3-E4) were analyzed in order to investigate the relationship between golf shoe design and swing performance. The findings indicated that type C golf shoes would be beneficial for stability and control of movement during address and swing performance. Furthermore, faster speed of golf shoes, center of mass, and both feet were observed with Type C golf shoes. It is expected that golfers with Type C golf Shoes provide greater force as they control the center of mass faster and increase rotational force during impact compared to other golf shoes.