• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.179-195
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• 2002

The purpose of this research is to provide a proper model by analyzing the sports biomechanical of physical movements on the basis of the two patterns(open-stance and cross-stance) at the ready-to-start pose. The subjects for this study are composed of five male handball players from P university and five female shooting players from S university. Three-way moving actions at start(right, left, and forward) are recorded with two high-speed video cameras and measured with two Force platforms and a EMG system. Three-dimensional action analyzer, GRF system, and Whole body reaction movement system are used to figure out the moving mechanisms at the start pose. The analytic results of the moving mechanism at the start pose were as follows. 1. Through examining the three-way moving actions at start, I have found the cross-stance pose is better for the moving speed of body weight balance than the open-stance one. 175 degree of knee joint angle at "take-off" and 172 degree of hip joint angle were best for the start pose. 2. The Support time and GRF data shows that the quickest center of gravity shift was occurred when cross-stanced male subjects started to move toward his lefthand side. The quickest male's average supporting time of left and right foot is 0.19${\pm}$0.07 sec., 0.26${\pm}$0.06sec. respectively. The supporting time difference between two feet is 0.07sec. 3. Through analyzing GRF of moving actions at start pose, I have concluded that more than 1550N are overloaded on one foot at the open-stance start, and the overloaded force may cause physical injury. However, at the cross-stance pose, The GRF are properly dispersed on both feet, and maximum 1350N are loaded on one foot.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.224-229
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• 2019

This study was undertaken to provide correct posture guidance and reference material for sports injury and injury prevention programs, by analyzing body alignment and plantar pressure distribution in high school baseball players. Totally, 32 subjects were enrolled for the study. Body alignment was measured from the trunk imbalance, kyphotic angle, lordotic angle, pelvic tilt, and pelvic torsion. Foot pressure was measured from the left maximum pressure, right maximum pressure, left weight, and right weight. The mean and standard deviation of the measured factors were calculated and tabulated, and the correlation between body alignment and foot pressure distribution was analyzed using Pearson's correlation analysis. All statistical significance levels were set at 0.05. Body alignment and foot pressure distribution show a positive correlation between the lordotic angle of lumbar spine and the left maximum pressure. There was no correlation between trunk imbalance, kyphotic angle, lordotic angle, pelvic tilt, pelvic torsion, and the left·right weight distribution and the left·right maximum pressure of each foot. Results of this study determined that the increase of the lordotic angle of lumbar spine results in more force on one side of the foot, thereby increasing the maximum pressure. We believe our data could be a reference for exercise programs on physical alignment and plantar pressure distribution of athletes.

• Journal of Life Science
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• v.19 no.12
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• pp.1821-1828
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• 2009

The purpose of this research was to investigate how the plyometric training and weight training program, applied in the field for exercise performance of throwing players, influenced improvement of athletic abilities, including agility, maximum muscular power, and strength. After implementing plyometric training and weight training to 21 high school throwing players for 10 weeks, we designed the next step. The 21 subjects were divided into two groups - women's group and men's group. All subjects were tested to determine agility using sidestep, burpee test, reaction time, lower body power and strength using standing long jump, standing jump, 30 m running, squats and leg presses. Additionally, isokinetic strength was measured using Cybex isokinetic dynamometer. The results showed that both groups demonstrated improvement in the standing long jump, standing jump and 30 m running after training. Particularly, the women's group indicated better improvement. Second, women's groups showed higher improvement in the sidestep and burpee test. However, in the reaction time test, the men's group indicated better improvement. Third, both groups showed better improvement in squats and leg presses after training. Particularly, the women's group indicated better improvement. Fourth, in the left and right side extension torque and flexion torque at a velocity of $60^{\circ}$/sec, both groups showed better improvement after training. In the left side extension peak torque, the men's group showed higher improvement, but the women's group showed higher improvement in the left side flexion and extension peak torque. Fifth, both groups showed better improvement in bench pressing and back strength after training. Particularly, the women's group indicated higher improvement.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.671-680
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• 2009

We performed a study to obtain kinematic data on the characteristics of spike serving techniques used by volleyball players, including other basic data that will be useful for in-field applications. We used three-dimensional videography to compare good tough serves and serve errors. The subjects were 3 left attackers whose spike serves were videographed (60 fileds/s). The three-dimensional coordinates were calculated using the direct linear transformation method and then analyzed using the Kwon 3D software program version 3.1. There was no difference in time elapsed. However, the vertical displacement of the center of body mass(CM) differed between the 2 types of serves: in successful serves, the CM tended to be lower, as did the maximum ball height at the time of hitting. Further, the higher the level of the hitting hand was at the moment of impact, the higher was the likelihood of scoring points. In good serves, the players tended to accelerate their CM movement just before jumping to hit the ball and descend rapidly at the moment of hitting. The hand speed along with ball velocity during the impact was proven to be higher in successful serves. Moreover, in successful serves, the shoulder angles increased to a greater extent while the elbow angles were maintained constant. This possibly resulted in faster and more precise serves. An important observation was that the angle of trunk inclination during the jump did not increase with the swing of the shoulders, muscle tendon complex.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.141-152
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• 2023

The scale of the authenticity perceived by the athletes of the domestic business team was developed. Through this, it is intended to accumulate information and authenticity research on human resource management of unemployment teams. The authenticity scale was developed through a total of 6 steps by referring to previous studies on the scale development process at domestic and international. In the first stage, the basic composition was confirmed through the review of previous studies.In the second stage, preliminary questions were drawn through in-depth interviews with 13 players belonging to the business team. In the third stage, the authenticity attribute and structure were confirmed through an expert meeting. In the fourth stage, the appropriateness of the items was verified through exploratory factor analysis and reliability analysis of 248 people. In the 5th stage, 288 subjects were tested for construct validity, convergent validity, and discriminant validity through confirmatory factor analysis, correlation analysis, and reliability analysis. The sixth step was to verify the relationship through regression analysis with the performance variables to examine the applicability and predictability of the developed scale. Through the above procedures, 4 dimensions of organizational authenticity and 18 measurement items were developed, and 3 dimensions of leader authenticity and 18 measurement items were developed.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.956-963
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• 2007

The purpose of the present study was to examine the effects of iron shot practice volume based on golf skill level on the indices of muscle damage and fatigue in blood. Twenty four golf players were studied under conditions of different golf skill level (beginners, intermediate, expert) and practice volume (100, 200, 300balls). In this study blood CK and LDH were determined to show the level of muscle damage, and blood phosphorus, lactate, and ammonia were measured to see the level of fatigue. Blood creatinine, and IGF- I generally used to see the rate of protein synthesis were also measured. In summary, these results are interpreted to mean that 1) blood fatigue factors, muscle damages, and creatinine levels increased due to a rise in the practice volume of iron shot, 2) those levels decreased due to rise in the golf skill level, 3) blood fators and creatinine recovered quickly after exercise, however muscle damages did not recover even after 24hr, Therefore, both golf skill lev-el and practice volume should be considered to prevent muscle damage and fatigue during practice iron shot.

• Journal of Industrial Convergence
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• v.19 no.1
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• pp.147-158
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• 2021

This study was conducted seven times from 2007 to the 2019 Women's World Handball Championships to analyze and strengthen the strength of the Korean women's handball team through the analysis of the top five countries' strengths. Among the 41 national teams participating in the World Women's Handball Championship, a total of five national teams, including the Netherlands, Norway, Russia, Spain, and France, were selected for the final study. Among the records provided by the International Handball Federation (IHF), the ranking was selected by analyzing the competition records of 41 participating countries, and technical statistics and frequency analysis were conducted using the SPSS/PC+ Ver21.0 program. based on the accumulated records of the top five women's handball competitions, handball attack and defense strategies that can make up for the inferiority in future physical conditions are needed and detailed follow-up studies are needed. Also, we hope to use it as a basic resource for improving the performance of Korean women's handball players and to play a key role in enhancing the level of women's handball at the 2021 Tokyo Olympics.

• Journal of Korea Game Society
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• v.12 no.1
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• pp.67-77
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• 2012

With the development of tangible interface in recent years, the interest in interactive exercise games to improve health-related physical fitness has been increased. We believe that this kind of serious game should provide not only motion sensing of the action required to play sports but also a specific effectiveness of exercise. This paper will show how a serious exercise game affects theirs heart rate and preference. For the experiments, we used an exercise game named GalaxyBike for aerobics exercise which is developed by the Interaction Media Research Center of Hoseo University. In the experiments, players' heart rate was measured during the warming-up, exercise and cooling-down periods by a wireless heart-rate measuring instrument. After they played the exercise game, a survey was conducted to see how they like this serious exercise game. The findings of the study suggest that the serious exercise game providing both video game and exercise would make a contribution to the improvement of health-related physical fitness since it serves to increase the heart rate and motivation.

• Korean Journal of Applied Biomechanics
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• v.27 no.3
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• pp.219-227
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• 2017

Objective: The aim of this study was to analyze the effects of bobsleigh shoes on the lower extremity range of motion and start speed lap time and to develop bobsleigh shoes suitable for winter environments and Korean players based on sports science and optimized biomechanical performance. Background: The bobsleigh shoes used in the start section of the sport are one of the most important equipment for improving athletes' performances. Despite the importance of the start section, there are no shoes that are specifically designed for Korean bobsleigh athletes. Thus, Korean athletes have to wear sprint spike shoes instead of bobsleigh shoes to practice the start. Method: The subjects included four bobsleigh athletes from the Gangwon Province Bobsleigh Skeleton Federation. The study selected the bobsleigh shoe type A (company A) and type B (company B). We analyzed the lower extremity range of motion and sprint time (start line to 10 m) using a Motion Analysis System (USA). Results: In the measurement of the time required for the bobsleigh start section (10 m), the type A shoes demonstrated the fastest section record by $2.765{\pm}0.086sec$ and yielded more efficient movements, hip and knee flexion, hip extension, ankle dorsiflexion, plantar flexion, and inversion than the type B shoes. Conclusion: Type A shoes can yield a better performance via effective lower extremity movements in the bobsleigh start section. Application: In the future, functional analysis should be conducted by comparing the upper material properties, comfort, and muscle fatigue of bobsleigh shoes based on the Type A shoes to develop such shoes suitable for Koreans.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.41-48
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• 2008

The purpose of this study was to analyze the lower extremities joint moment pattern by two types of service motion in tennis pinpoint and platform stance. Seven skilled high school tennis players participated, and the kinematics were recorded by the Vicon motion analysis system. For the gathering and analysis of the data Workstation, Bodybuilder and polygon were used. joint moments and Ground Reaction Forces for the phases involved were analyzed with the following results. There was a different moment pattern for the lower extremities between the two serve motions. For the platform stance there was only a large dorsal flexion moment but for the pinpoint stance there were other large moments. The flexion and maximum moment of the lower extremities occurred at the point of change from back swing and to the forward swing motion. Therefore, this data provides evidence that there is a high risk of injury at this point.