• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.229-244
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• 2002

The purpose of this study were a two-fold: (1) to analyze event and phase of handspring salto forward stretched with turn; (2) to know the differences in the kinematic variables between two groups. A Kwon3D program served for the estimation of this study. The group was divided into three National representative and three well-trained calisthenics in this study. The results of this study revealed that (1) the forward somersault performance was increased when duration time in the air was long during the salto forward stretched that the duration time of Handspring is short, the pressure at takeoff is high, the stride is large, and hands are supporting on the ground quickly; (2) comparing the angular movement of anterior and posterior y axis and vertical z axis, the angular movement of right and left $\times$ axis was higher during the performance. As a result, the national representative players showed better performance in Handspring salto forward stretched with turn.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.509-517
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• 2009

The purpose of this study was to investigate the effective posture for air pistol shooting. Participants were 3 male athletes of shooting with at least five years of experience and another group of 3 males athletes with less than three years of experience. For the purpose, the shooting motion was analysed using three dimensional image technology. Data from each event for the two groups, competent and less competent ones, were compared to see the differences from the kinematical point of view. Time of period in competent group was longer than less competent group during the shooting posture. Displacement of center of mass and pistol about medial/lateral and antero/posterior in competent group was little than less competent group from aim to shooting. And these result were effect to the velocity. Distance and time in competent group within coaching machine were smaller than less competent group. To the result, it was appear that precision of aim in competent group was higher than less competent group.

• Korean Journal of Applied Biomechanics
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• v.19 no.3
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• pp.467-479
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• 2009

The purpose of this study was to present the quantitative data which riders can utilize teaching field by comparison analysis of kinematics according to skill level of rider during 2 strides rising trot with the JeJu's-Horse. Participated subjects was consisted of total 10 riders(unskilled: n=5, skilled: n=5). The method of experiment & analysis was based on 3D cinematography. Variables were consisted of temporal, linear & angular kinematics by each event & phase. The skilled assigned more ratio of elapsed time in air than support phase, had the less range of motion in up-down direction and more consistent velocity in lateral & forward direction and performed periodic up-down movement with alignment in vertical direction according to elapsing of phases. The skilled more flexed at elbow and extended backwardly according to elapsing of phases, while more flexed forwardly at hip & knee and plantarflexion at ankle. The skilled postured backward extension but the unskilled do forward flexion. That is, It was considered that the unskilled continued more unstable posture than the skilled during 2 strides in rising trot.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.109-130
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• 2002

The purpose of this paper was to make a comparative analysis for the difference of the various kinematic variation which is occurred in the each situation when pitchers throw a straight and a curve ball. Four pitchers, who are two national team players and two high level pitchers, were selected among the right over hand pitchers of D university in the Busan for this paper. The data were analyzed by using 3D equipment. The results of the analysis which was about the elapsed time of the pitching, the movement of the body center-point, the highest height of the left knee, stride length, knee joint angle, shoulder joint angle, elbow joint angle and wrist joint angle in the each section(ST, LKU, HBP, LCF, MCP, BRP) were as follows : 1. Pitching time in the each section and step in the pitching for straight and curve ball was similar. The total elapsed time of the straight and curve ball was 1.78${\pm}$0.07sec and 1.77${\pm}$0.11sec in the order. 2. The position change of the body center to the Z(above below) direction did not show significant difference in the each situation of the section and step between pitching for the straight and curve ball. 3. Height of the left knee did not show significant difference as 125.38${\pm}$11.85cm and 124.95${\pm}$11.63m in the each pitching motion for straight and curve ball. The rate(%H) between height and stride length showed 68.42${\pm}$5.53(%H), 68.40${\pm}$5.45(%H) in the each pitching motion. 4. Pitching for curve ball showed longer stride length than pitching for straight ball that as the stride length was 140.35${\pm}$4.96cm and 144.8${\pm}$1.69cm. The rate(%H) between height and stride length showed 76.9${\pm}$3.77(%H), 79.39${\pm}$2.23(%H) in the each pitching motion. 5. Left knee joint angle did not show significant difference in the ST, LKU and HBP section in the each pitching motion. However, it was shown that knee joint angle was flexed much more in the LFC, MCP and BRP section in the pitching for curve ball. 6. Right shoulder joint angle did not show significant difference in the ST, LKU and HSP section. However, when pitches threw a curve ball in the LKU section. In the LFC section, the right shoulder joint angle was extended much more in the pitching for curve ball, and the angle was extended much in the MCP and BRP section in the pitching for curve ball than straight ball. 7. Right elbow joint angle did not show significant difference in the ST, LKU and HRP section in the two pitching motion. The angle had more flexion in the LFC and MCP section in the pitching for curve ball than the pitching for straight ball. The angle in the each pitching motion for straight ball and curve ball were extended by a narrow margin in the BRP section. 8. Right wrist joint angle was extended much more in the LFC and MCP section in the pitching for curve ball. In the BRP section, the angle was extended much more in the pitching for straight ball than curve ball.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.67-76
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• 2008

The purpose of this study was to analyze differences in kinematic variables for mogul short turn motion between superior and inferior group, so that it can explore more effective mogul short turn motions. To meet the goals, this study selected total 10 ski players who would participate in mogul short turn event of the National Technical Ski Championship 2007, so that it could analyze kinematic variables by way of 3D motion analysis using DLT method. As a result, this study came to the following conclusions; For total and phase-specific duration, it was found that superior group took shorter time than inferior group. Superior group's Center of Mass was stands for more high value in up-down movement skill than inferior group. However right-left movement scale was less than them. In this reason, superior group was made a straight descent at the same time made a fast front-rear velocity. In the part of up-down movement velocity show that move slowly in the drop-in phase while increased in the bump-up phase. It is show that superior group was less tinny than inferior group include joint angle and knee joint angle. However leaning angle of trunk and the body inclination angle were more high figured than inferior group. Leaning angle of lower limbs also showed high figure at the center mogul. Lastly, In the part of body torsion angle show that superior group was high figure direction of right turn in the drop-in phase while in bump-up phase, made a high figure direction of left turn.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.345-359
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• 2002

The purpose of the study was to provide the fundamental data to instruct athletes through the analysis athletes' movement in javelin. Three athletes in the level of national representative were participated in this study. The study analyzed kinematic variables(lead foot and releasing javelin) through 3-D analysis and obtained the following results. 1. During withdrawal, it is important to maintain of running horizontal velocity. 2. It was showed that throng average height was $84{\pm}3.3%$ and javelin adequative degree, Among the athletes, $S_2$ who had the best record was released the javelin with the fast velocity, but throw the javelin with the less releasing velocity. 3. $S_2$ released after lead foot were completely landed and therefore it is no problem in a kinematic aspect. However, $S_1$ angle was too small. it caused increase of release velocity to be prevented. 4. $S_2$ showing the best result indicated shorter in duration time. Generally, the shorter duration time in release phase showed the longer release distance. Especially $S_1$ and $S_3$ showing the worse result indicated the longer duration time in preparatory phase, causing the breakup of force. Therefore to improve the record, it should be decreased the duration time in preparatory phase. 5. Compared with $S_1$ and $S_3$, $S_2$ showing the best record indicated the higher velocity in center of mass, trunk, upper arm, lower arm and hand That is the higher velocity of upper arm at release leaded the better velocity transfer from upper arm to following lower arm and hand, these action should be considered to be helpful of better record. According to the above conclusion, when the athletic leaders cauch athletes, they should focus on maintaining knee angle, upper body and hip angle in a previous stage of release and throwing angle, throwing height, throwing velocity in a release stage.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.141-153
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• 1986

This study intends to document the existing cyclical fluctuations of garic and onion price at farm gate level during the period of 1966-1986 in Korea. The existing patterns of such cyclical fluctuations were estimated systematically by removing the seasonal fluctuation and irregular movement as well as secular trend from the original price through the moving average method. It was found that the cyclical fluctuations of garic and onion prices repeated six and seven times respectively during the same period, also the amplitude coefficient of cyclical fluctuations showed speed up in recent years. It was noticed that the cyclical fluctuations of price in onion was higher than that of in garic.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.143-157
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• 2002

This study was to analyze the kinematic variables when the subjects performing Uchi-mata(inner thigh reaping throw) by Kumi-kata types((How to grasp A or B?) and two different opponent's height in Judo. Kinematic variables were temporal, posture. Data analysis was collective comparison of two-way ANOVA, t-test by type A&B and two different opponent's height. There were significant difference of Kumi-kata types(p<.05) in the time elapsed on Kake phase(KP : throwing phase) and hip, knee, ankle-angle of the attacking foot in the 1st stage of KP and knee, ankle-angle of the attacking foot and hip, knee ankle-angle of the supporting foot in the 2nd stage of KP. There were significant difference of two opponent's(p<.05) in the time elapsed on KP and hip-angle of the supporting foot in 1st stage of KP. Therefore, the interaction effect(p<.05) were in the time elapsed on KP and hip-angle of the supporting foot in the 2nd stage of KP. So, It could be suggested that Judoka hold on the part-behind neck lapel(type A) at the sleeve with the other of Judogi jacked when opponent's height was short. Because the time elapsed on KP of type B was not so fast as type A(p<.05) during performed Uchi-mata, and also the bigger hip-angle of the supporting foot in the 2nd stage of KP grew, the faster the time elapsed on KP became.