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Korean Journal of Sport Biomechanics
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Korean Society of Sport Biomechanics
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Volume & Issues
Volume 12, Issue 2 - Aug 2002
Volume 12, Issue 1 - Apr 2002
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The effects of strength training on the change of ground reaction force for the children with Down syndrome
Lim, Bee-Oh ; Han, Dong-Ki ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 1~16
DOI : 10.5103/KJSB.2002.12.2.001
The purposes of this study were to investigate the effects of strength training on the change of ground reaction force for the children with trisomy 21 Down syndrome. The subjects of this study were consisted of eight elementary school students with Down syndrome who participated in the strength training. The strength training was administered by six items such as squat, leg curl, leg extension, toe raise, sit-ups, and hyperextension. For strengthening muscle, each group also was treated by walking for 8 weeks, three times a week, 10-15RM, 3sets, which was based on the principle of progressive overload. For inquiring the effect of strength training, the ground reaction force variables were measured in two phases : before-training and 8 week-after training. The gait of each subject was acquisition using 2 AMTI force platforms set at 100 frequency. The results of this study were as follows: The pattern of vertical, antero-posterior and medio-lateral forces, trajectory of net COP and the timing ratio of reaching the each events were shown variously. So, it is not easy to explain these variables clearly. As the result of strength training, these variables were changed. However, the results of within subjects differ greatly, there was no difference statistically.
Analysis of golf swing motion for specific properties of club shaft
Kim, Sung-Il ; Kim, Ky-Hyoung ; Kim, Hyung-Soo ; Lee, Hyun-Seob ; Kim, Jin-Uk ; Ahn, Chan-Gyu ; Kim, Hee-Jin ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 17~32
DOI : 10.5103/KJSB.2002.12.2.017
The purpose of this study was to find the rational method to analyze golf swing with specific property of club shaft. Three subjects were filmed by two high speed digital cameras with 500 fps. The phase analyzed was downswing of each subject. The three-dimensional coordinates of the anatomical landmarks were obtained with motion analysis system Kwon3d 3.0 version and smoothed by lowpass digital filter with cutoff frequency 6Hz. From these data, kinematic and kinetic variables were calculated using Matlab(ver 5.0) The variables for this study were angular velocity and accelerations, which were calculated and following conclusions have been made : 1) Golf swing time of stiff club is faster than that of regular club. 2) In shoulder joint motion of swing with the stiff club, x-stiff showed mort rapid negative acceleration than that of regular club. 3) In regular club, the velocity of club head would be more effective velocity, which was increasing, than those of other clubs before impact. 4) In wrist joint motion of swing with stiff club, x-stiff club showed faster than regular club in the downswing and impact more rapid negative acceleration.
A Comparison of the Difference in the Golf Swing Motion According to Somatotypes
Chung, Nam-Ju ; Yoon, Hee-Joong ; Baik, Young-Soo ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 33~49
DOI : 10.5103/KJSB.2002.12.2.033
This study was intended to provide basic materials for golf coaching by somatotype by analyzing and comparing the kinematic factors found in each somatotype at the time of golf swing. For this purpose, the somatotype was divided into endomorph, mesomorph and ectomorph in reference to the weight, height and upper arm circumference of each of nine professional golfers. Each of their swing motions was videotaped with the camcorder and their swing motion was analyzed by dividing it into 8 sections. The time required for the swing motion, the displacement of the center of the human body and the rotation angle of the upper body were calculated through the three-dimensional image analysis based on the DLT(Direct Linear Transformation). Based on the findings of this study, the following conclusion was drawn: The endomorphic golfers showed the longest required golf swing time, followed by the mesomorphic golfer and then the endomorphic golfer. The displacement of left-to-right movement was largest in the mesomorphic golfers, followed by the endomorphic golfers the up-to-down displacement was upward at the time of impact and that the endomorphic and mesomorphic golfers raised the sense of stability by maintaining an almost uniform height at the time of impact. As for the rotational angle of the upper body and the rotational angle of the thigh, the upper body and the thigh took a form of rotating earlier in the ectomorphic golfers at the time of impact, who showed a somewhat different characteristics compared to the endomorphic and mesomorphic golfers. It is necessary to investigate the movement of more fundamental forces in presenting the theory related to the kinematic characteristics of this swing by somatotype. Accordingly, it is thought that it is necessary to analyze the center of pressure(COP) using the ground counterforce in the future study.
Analysis of the Kinematic Characteristics at Entrance to the Straight Course from the Curvilinear Course in the 200m-Track Game
Oh, Sei-Jin ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 51~63
DOI : 10.5103/KJSB.2002.12.2.051
This study sought to identify the kinematic characteristics at entrance to the straight course from the curvilinear course in the 200m-track game. For this purpose, this study was conducted for 4 sprinters by setting the 10m-section combined from the curvilenear track to the straight course and shooting them with the camcorder. It was set up to include all the sections of analysis by using the framework of the control point knowing the coordinate of the space and actual analysis was conducted on the motion showing the best records by conducting it for each subject five times. As a result, the following conclusion was drawn: It was found that the subjects showed the average stride of 4.5
0.41 times at the 10-meter section and the required time of 1.42
0.04sec. They showed the ratio average stride to height of 1.25
0.20% and the average speed of 7.06
0.19m/s. The displacement in the center of gravity of the human body at the section combined from the curvilinear course to the straight course was moving along the inward course of the curvilinear course, and the displacement of the leg located at the outward direction(right) was found to be larger than that of the leg located at the inward direction(left). In the speed of the left and right hand segments, it was found that the speed of the right hand located in the outward direction was faster than that of the left hand located at the inward, and it was found that the subjects progressed in the curvilinear course. The subjects showed the larger angle of the shoulder joint when the upper arm was located in the forward direction than when the it was located in the backward direction. In the curvilinear course, they showed the lower value of the lateral angle of the trunk when the right foot located at the outward direction left the ground than when the left foot located at the inward direction left the ground. And it was found that the lateral angle of the trunk became lower with approaching the straight course.
Analysis of Kinematic on Ring jump in the Rhythmic Sport Gymnastics
Woo, Byung-Hoon ; In, Hee-Kyo ; Lee, Kae-San ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 65~75
DOI : 10.5103/KJSB.2002.12.2.065
The study has a goal that produces abundant documents that needed for athletes to teach and progress skills by analyzing 3-dimensional action analysis of C-difficulties Ring jump included in body original elements among techniques constructing Rhythmic Sport Gymnastics. 1. It was the longest applied time delay that E-3 indicates 0.409
0.017sec in each event applied time delay. 2. It was the tallest height that E-3 indicates 88.5
1.3% in displacement of body's center. 3. It was the fastest velocity in E-2 where the velocity of left foot is 732.4
46.1cm/sec, the velocity of right foot is 1958.4
25.1cm/sec. 4. the lowest angle was founded at 97.8 degree in the E-3 on the trunk extension angle. 5. The lowest angle of both sides were seen at 92.8
14.9degree and 69.2
5.7degree in the E-3 on the each displacement of knee joint. 6. The highest angle of both sides were seen at 171.3
6.9degree and 167.9
8.4degree in the E-3 on the each displacement of ankle joint As a result of these studies, by jumping with ankle joint extension to accomplish the Ring jump action, it is considered to have the time of flexiblity and staying in the air which we can see in a back.
The Kinematical Analysis of Straddle Jump to Push up Motion on Sports Aerobics
Kim, Cha-Nam ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 77~90
DOI : 10.5103/KJSB.2002.12.2.077
This study serves the purpose of understanding about correct jump and landing motion through Kinematical Analysis of Straddle Jump to Push up Motion at target by four elite sports aerobics athletes have more than four years career. And further more that make good assistance for coaches effective guidance through an offer basic data and correct diagnosis, evaluate of motions. It was picture-taked by two-video camera for Straddle Jump to Push up Motions. Camera speeds are 60 frame/sec. There are Kinematical Variation elements for analysis, the displacement of COG, each angle displacement left/right of shoulder-joint, each angle displacement left/right of knee-joint and each speed left/right of tip of the toes. Every each person accomplished severaly 3 times and we have acquired this conclusion. The conclusions were as follows; 1. Each situation for displacement of COG showed low height of COG by phase 1, 4, 5(79.05
) and It showed high height of COG by phase 2, 3(
). 2. Each displacement left, right of shoulder-joint flexion by phase 1(
deg/sec)and It showed maximal extension angles by phase 2(
deg/sec). in part of phase 3, left of shoulder-joint angle(
deg/sec) showed flexion phase 1, the other right shoulder-joint angle(88.38
4.98deg/sec) showed more a little lower than phase 1, in last phase that showed most low by phase 4(
deg/sec). 3. Each displacement left, right of hip joint showed maximal extent conditions by phase 2, 3(
deg/sec) beside, ankle-joint showed minimal angle by phase 1, 4(
deg/sec). 4. Each displacement left, right of hip joint showed maximal extent conditions by phase 2(
deg/sec), and right of hip joint showed minimal angle by phase 3(
deg/sec) It showed alike condition of low angle by phase 1, 4(
deg/sec). 5. Each displacement left, right of knee-joint showed maximal extent conditions by phase 1, 3, 4(
deg/sec) but It showed flexion only left of knee-joint by phase 2(
deg/sec). 6. Each speed left, right of the tip of the toes showed most fastest when someone jumped with lift up leges by phase 1, 2(
cm/sec), It showed more less speed than phase 1,2 by phase 3(
cm/sec) and It showed most slow speed than phase 1,2,3 by phase 4(
The Kinematics Analysis of the Badminton High Clear Motion in Woman Middle School Student
Kim, Chang-Bum ; Ryu, Jae-Kwang ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 91~107
DOI : 10.5103/KJSB.2002.12.2.091
This research got the following conclusion as result that analyzed high clear action kinematically to 4 C girls' junior high school badminton players who are situated in Chungchong-bukdo. 1. Most of the subject didn't rotate their right shoulder and elbow joint at back swing and moved speedy to shuttle cock. And an cooperation action of joint decreases displaying only a good action on both subject`s specification joint part. 2. When the subject S1 and S2 swing slowly and largely the joint of shoulder and elbow and then the speed of right wrist and racket head is fast, the cooperation action of joint is better than other subject. 3. An angle change of right shoulder showed angle that all subjects are great being caused in softness of joint and angular velocity was exposed that load enough Impact force and increase the speed of racket head as angular velocity decreases rapidly in Impact except subject S3. 4. All subjects of right elbow angle change showed similar form and was exposed that subject S2 sees form of impact stage serious bends from back swing and do not use force effectively in angular velocity. 5. Angle of right wrist appeared that the speed of shuttle cock is decelerated because fast bends of wrist is not formed shortly after Impact because all subject do not accomplish big angle shortly after back swing. Angular velocity can assume that the subject S1 and S4 are using and move fast strong snap shot offering angular velocity value of Impact stage sound (-). 6. While size of Impact stage knee angle accomplishes angle that is big both subject, hip joint angles sees small angle and is playing swing that do on upper body and arm without using strong waist force that is composition action with knee and hip joint.
The Kinematic Analysis of the Pitching motion for the Straight and Curve ball
Lee, Young-Jun ; Kim, Jung-Tae ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 109~130
DOI : 10.5103/KJSB.2002.12.2.109
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
0.07sec and 1.77
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
11.85cm and 124.95
11.63m in the each pitching motion for straight and curve ball. The rate(%H) between height and stride length showed 68.42
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
4.96cm and 144.8
1.69cm. The rate(%H) between height and stride length showed 76.9
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.
A Kinematical Analysis of Mae-ukemi (forward breakfall) in Judo
Kim, Eui-Hwan ; Kim, Ji-Tae ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 131~142
DOI : 10.5103/KJSB.2002.12.2.131
The purpose of this study was to analyze kinematic variables of a Mae-ukemi (forward breakfall :MU) in Judo through 3-D image analysis with five Judoka with over 2 years' career (2nd dan, 3rd dan). The kinematic variables include posture, and distance variables; the mean values and the standard deviations for each variable were obtained to analyze kinematic variables of a MU in Judo. From the data analysis and discussion, the following conclusions were drawn : 1) Posture variables : The angles of wrists during right before Mae-ukemi (RBU) were extended from the just MU position(MUP) and flexed from in the right after MU(RAU), and there was a difference in the displacement between the angles of the right and left wrists. The angles of elbows were flexed in the ready position from in the RAU. The angles of ankles were flexed from the ready position to that down position, extended from the down position to that transition, and flexed from the transition positiont to that RAU. 2) Distance variables : The distance height between the mat and shoulders in the RBU(32.2cm) to in the MUP(18.3cm) and in the RAU(20.5cm). during that height between the mat and hips in the RBU(48.0cm) to in the MUP(23.4cm), and in the RAU(30.6cm).
A Kinematics Analysis of Uchi-mata(inner thigh reaping throw) by Kumi-kata types and Two different Opponent's Height in Judo[II]
Kwon, Moon-Seok ; Kim, Eui-Hwan ; Cho, Dong-Hee ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 143~157
DOI : 10.5103/KJSB.2002.12.2.143
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.
Kinematic Analysis of Airborne Movement of Dismount from High Bar(I)
Choi, Ji-Young ; Kim, Youg-Ee ; Jin, Young-Wan ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 159~177
DOI : 10.5103/KJSB.2002.12.2.159
The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle and the angular velocity of the air born phase and understand the control mechanism of the high-bar movement, the somersault, the double somersault, the double somersault with full twist. For this study seven well trained university gymnastic volunteered, Zatsiorky and Seluyanov(1983, 1985)'s sixteen segment system anatomical model was used for this study. For the movement analysis three dimensional cinematographical method(Arial Performance Analysis System : APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 5.1 graphical profromming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and angular velocity were defined. As a result of this study 1. As the rotation of the body increased in the air born phase the projection angle of the CM of the total increased, this resulted the increased of the max hight of the CM. 2. In three dimensional angular velocity the Z axis(vertical direction) projection angular velocity increased as the rotation of the body increased in the airborn phase, but the Y axis and the X axis projection angular velocity did not show significant differences. 3. As the rotation of the body increased in the air born phase the angular movement of the shoulder and the hip showed significant change. These movement act as the starter in the preparation phase. 4. The somersault angle, the twist angle, the tilt angle of the upper body related to the global reference frame in the releas phase the average somersault angle of the three types of high-bar movement was
, the average tilt angle was
, the average twist angle was
. This result showed that the somersault with full twist had the largest movement.
Sports Biomechanical Analysis of Physical Movements on the Basis of the Patterns of the Ready Poses
Lee, Joong-Sook ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 179~195
DOI : 10.5103/KJSB.2002.12.2.179
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
0.07 sec., 0.26
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.
Comparisons of Putting Stroke Characteristics between Expert and Novice Golfers(I)
Park, Jin ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 197~206
DOI : 10.5103/KJSB.2002.12.2.197
The purpose of this study was to investigate the putter head movement during the putting strokes. Highly skilled 5 golfers(less than 3 handicaps) and 5 novice golfers(having no golf experience) participated in this study. A target distance was 3 m. Movements of the putter head were recorded at 60 Hz with two video cameras. The results showed that the novice golfers moved the club significantly longer than the expert golfers(p<.0001). Accoring to a movement time, novice golfers moved their club significantly faster than the expert golfers(p<0.001). Novice golfers could not control the club head effectively, and could not hit the ball correctly. Based on the impact zone movement, sweet spot of novice golfers moved faster(along the line of putt), higher(along the vertical line), and wider(along the side to side line) than that of expert golfers.
Comparisons of Putting Stroke Characteristics between Expert and Novice Golfers(II)
Park, Jin ; Lee, Young-Sup ; Ahn, Byoung-Hwa ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 207~214
DOI : 10.5103/KJSB.2002.12.2.207
The purpose of this study was to examine the putter head movement during the putting strokes. Highly skilled 5 golfers(less than 3 handicaps) and 5 novice golfers(having no golf experience) participated in this study. A target distance was 3 m. Movements of the putter head were recorded at 60 Hz with two video cameras(1/500 shutter speed). The results showed that the angle of the clubface of expert golfers was almost 1 degree, but the novice golfers were more than 6 degrees. Expert golfers moved their hands faster than the head movement, therefore the clubface was not opened during impact. However, the novice golfers moved their hands slower than the head movement, therefore the clubface was opened during impact. The ratio of input and output angles of total movement was 1:3-4, however, the ratio of input and output angles of impact zone was 1:2. The angle of normal vector of expert golfers was less than the angle of normal vector of novice golfers.
The effects of three basketball wheelchairs on propulsion movement
Lim, Bee-Oh ; Yu, Yeon-Joo ; Seo, Joung-Seok ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 215~227
DOI : 10.5103/KJSB.2002.12.2.215
The purpose of this study was to investigate propulsive time and kinematic variables on the three different kinds of the basketball wheelchairs in each play position for eight abled basketball wheelchair players. Kinematic data were collected by a video camera for two-dimensional analysis. The wheelchairs for the guard position showed the fastest in total propulsive time. The wheelchairs for the center position revealed the slowest in the phase of the change of the direction. The wheelchair for the guard position which shows fast movement velocity demonstrated closer hand contact with TDC(Top Dead Center). The wheelchair for the center position revealed the largest extension of the elbow and flexion of the trunk at handrim contact. The wheelchair for the guard position which has the lowest seat height presented larger elbow angle and trunk angle. The wheelchair for the guard position produced more fast trunk angular velocity than the wheelchair for other positions.
An analysis angular movement and performance time during handspring salto forward stretched
Kwon, Oh-Seok ; Yoon, Yang-Jin ; Seo, Kuk-Woong ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 229~244
DOI : 10.5103/KJSB.2002.12.2.229
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
axis was higher during the performance. As a result, the national representative players showed better performance in Handspring salto forward stretched with turn.
Development of The New Instrument for Measuring of Trunk-Hip Forward Flexion
Lee, Gun-Bum ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 245~257
DOI : 10.5103/KJSB.2002.12.2.245
The purpose of this study was to develop a simple, valid, and reliable instrument for measuring forward flexion of trunk-hip joint. The subject included 44 females for sports major of volunteers at D. Women's University. In establishing the validity, objectivity the reliability of the new flexibility test(NF-test) for trunk-hip joint, Takei- flexometer(modified Leighton flexometer) was administered as the reference instrument, and test-retest method was utilized with the best scores. Intraclass correlation coefficient was obtained to use two way-mixed effect model and this value was average measure. The Pearson product correlation coefficient of L in this study were; the new flexibility test and Takei-flexometer as the reference tool correlated r = .962 in the first test, r = .960 in the second test. The intraclass correlation coefficient of the new flexibility test between in the initial test and in the retest were R = .994 for L, R =.993 for Y, and the intraclass correlation coefficient of the new flexibility test between L and Y were R =.985 in the initial test, and R =.986 in the retest. Based on the above findings, the following conclusions are presented. It was found the new flexibility test (NF test) was a valid, reliable, objective tool for measuring forward flexion of trunk-hip joint, and possible to be recommended as he test for measuring trunk-hip flexibility in the field.
Biomechanics analysis by golf drive swing pattern
Choi, Sung-Jin ; Park, Jong-Jin ; Yang, Dong-Ho ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 259~278
DOI : 10.5103/KJSB.2002.12.2.259
This study divided straight success, pade success and failure with 7male golfers who have experiences more than 3 years, analyzed kinematic factors of golf swing to suggest scientifically. The conclusions were follows. 1) The wrist angle has significant difference in straight success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. 2) The body twist angle has no significant difference in straight success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. 3) The shoulder joint rotation angle has no significant difference in success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. 4) The left hip joint vertical angle has no significant difference in straight success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. 5) The hip joint rotation angle has no significant difference in straight success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. 6) The trunk angle has no significant difference in straight success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. 7 )The left knee joint angle has no significant difference in straight success, pade success and failure when swing of every pattern. There is no significant difference in pade success and failure. This study divided golf swing motion of pattern change in straight success, pade success and failure and analyzed the kinematic factors by 3-dimension cinematography to improve performance. In the future, many researchers have to study kinematic analysis to improve performance in every events.
Biomechanics analysis by success and failure during golf putting swing
Choi, Sung-Jin ; Park, Jong-Jin ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 279~293
DOI : 10.5103/KJSB.2002.12.2.279
In the study the subjects who 10 university golfers act, and the kinetic factors were analyzed by the ground reaction system. the conclusion are as follows. 1) In the golf putting swing, the ground reaction factors of sagital plane in aspect are showen that the left and right foot sufficient difference, in the level of p <.05. 2) In the golf putting swing, the ground reaction factors of frontal plane in aspect is showen that the left foot has no significant difference in AD BS in the level of p < .05. In success, IP, FS. It can show significant difference. In addition, the right foot is shown the success, There is significant difference. 3) In the golf putting swing, the ground reaction factors of the vertical plane in aspect are shown that the left foot has no significant difference in BS, FS in the level p < .05. In success, AD, IP. It can show significant difference. In addition, the right foot is shown the success, There is significant difference. 4) In the golf putting swing, the ground reaction factors of torque in aspect are shown that the left foot had no significant difference in BS in the level p < .05. In success, AD, IP, FS. It can show significant difference. In addition, the right foot has no significant difference in IP in the level p < .05. AD, BS, FS. There is significant difference. The summarized conclusions are as follows. The first that the power of sagital plane needs the motion which can get the good power change in the stabilized pose. The second is that the small motion can make good putting in stabilized pose. The third is that the body weight move to the direction of the ball. The fourth is that the putting which looks perfect oscillation is good motion.
A Analysis of Isotonic Torque of Shoulder Joint for Overthrow Pitcher of Professional Baseball Player
So, Jae-Moo ; Kim, Young-Il ; Kim, Hyo-Eun ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 295~306
DOI : 10.5103/KJSB.2002.12.2.295
The purpose of this study was analysis inter relative the ball velocity and isotonic torque of shoulder joint. The subject were twelve overthrow pitcher of professional baseball player. The measurement was used Cybex 6000. The results of this study were as follows : 1. As the siting position of maximal adduction torque of dominant, A group was higher than B group. As the non-dominant, B group was higher than A group for improved angular velocity. There is no significance difference between group. 2. As the siting position of maximal abduction torque of dominant and non-dominant, B group was higher than A group for all measurement. There is no significance difference between group. 3. As the layed position of maximal internal torque of dominant, A group was higher than B group. As the non-dominant was just higher at
/sec than B group, B group was higher at
/sec than A group. There is no significance difference between group. 4. As the layed position of maximal external torque of dominant and non-dominant, A group was more higher than B group for all measurement. There is no significance difference between group. 5. As the standing position of maximal internal torque of dominant, A group was just higher at
/sec than B group, B group was higher at
/sec than A group. As the non-dominant, B group was higher than A group. There is no significance difference between group. 6. As the standing position of maximal external torque of dominant, A group was higher
/sec than B group. But B group was higher
/sec than A group. As the non-dominant, B group was higher than A group. There is no significance difference between group.
Development of the Web-based Sports Biomechanics Class
Lee, Ki-Kwang ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 307~318
DOI : 10.5103/KJSB.2002.12.2.307
To provide a guideline for the development of a web-based sport biomechanics class in undergraduate program, thirty web sites, searched via search engines in May 2002, were analyzed intensively. In terms of requirement of log-in, only one site of 30 sites required user name and password. Seventeen(57%) sites provided the lecture note, which had various file formats such as 59% if PDF, 29% of HTML, and 12% of PPT. Fourteen(47%) sites provided the assignment and grade information on web. Eleven(37%) sites provided various resource and links which were related in sports biomechanics. Only four(13%) sites provided discussion or online digitizing or kinematic analysis program. Based on above results, a guideline for the development of a virtual classroom for college level sport biomechanics. A web-based sport biomechanics class should be developed with consideration of several functions as follows; homepage design, lecture note, measurement of class attendance, collaborative research system, and web-based data collection and analysis software for biomechanics laboratory.
Last's biomechanical function changes analysis for Marathone shoes last development
Park, Seung-Beom ; Seo, Guk-Ung ; Kim, Yong-Jae ; Yu, Seok-Ju ; Lee, Jung-Suk ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 319~330
DOI : 10.5103/KJSB.2002.12.2.319
A toe spring and ball girth data, when marathone shoes research, development, and production in Korea, is a important point in athlete shoe research. It is clear from the results presented that any differences between MA3 and MA1, MA4 in 70%, 80% session in forepart last comparision. Especially the more 70%-80% session getting wide, the more 90% session getting up, Also, To development for high performance marathones shoes last, in all session, in korean style, 70%, 80%, and 90% session part function changed and consequently there is a need for normative last data that desribe foot, last shape, dimension. this leads to the conclusion that unique shoe lasts for both marathone shoes developmented last comparison are required for optimal marathone shoe comfort. The more ball girth construction will wide in forepart in last, the more comfort characteristic sill development. But relative with performance ability, it is need to research. The further study of Korea marathoner forefoot measurements(70% session ~ 90% session) among toe spring's angular difference of marathone last to north american and Korea marathone shoes last is required to develop and improve athletes performance in an effective way of study and to prevent forefoot injury.
The Kinematical Analysis of Bowling Throw Motion
Baik, Sung-Kook ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 331~344
DOI : 10.5103/KJSB.2002.12.2.331
The purpose of this study was to compare between success and failure in bowling throw motions. For the data analysis, it was utilized by the method of three dimensional motion analysis and obtained kinematical parameters of stride, COG position and ball position through the address and release motion. The subjects of this study were three female bowling players, and obtained conclusions were as follows; Displacements of stride were not significance of success events, 4th and 5th phase stride were longer than failure. COG variation for height were less than failure, but there not significance between success and failure. The ball position of 3 th phase was lowest than other phases, and throw motions were stable by the small variations for upward downward.
Kinematical Analysis of Woman Javelin Throwing
Lee, Jong-Hoon ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 345~359
DOI : 10.5103/KJSB.2002.12.2.345
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
and javelin adequative degree, Among the athletes,
who had the best record was released the javelin with the fast velocity, but throw the javelin with the less releasing velocity. 3.
released after lead foot were completely landed and therefore it is no problem in a kinematic aspect. However,
angle was too small. it caused increase of release velocity to be prevented. 4.
showing the best result indicated shorter in duration time. Generally, the shorter duration time in release phase showed the longer release distance. Especially
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
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.
A analysis of friction relation between tennis outsole and tennis playing surfaces
Kim, Jung-Tae ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 361~380
DOI : 10.5103/KJSB.2002.12.2.361
The purposes of this study were to a analysis of friction relation between tennis outsole and tennis playing surfaces. Tennis footwear is an important component of tennis game equipment. It can support or damage players performance and comfort. Most importantly athletic shoes protect the foot preventing abrasions and injuries. Footwear stability in court sports like tennis is incredibly important since it is estimated that as many as 45% of all lower extremity injuries occur in the foot and ankle. The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. The friction force opposes the motion of the object. Friction results when two surfaces are pressed together closely, causing attractive intermolecular forces between the molecules of the two different surfaces. The outsole provides traction and reduces wear on the midsole. Today's outsoles address sport specific movements (running versus pivoting) and playing surface types. Different areas of the outsole are designed for the distinct frictional needs of specific movements. Traction created by the friction between the outsole and the surface allows the shoe to grip the surface. As surfaces, conditions and player motion change, traction may need to vary. An athletic shoe needs to grip well when running but not when pivoting. Laboratory tests have demonstrated force reductions compared to impact on concrete. There is a correlation between pain, injury and surface hardness. These are a variety of traction patterns on the soles of athletic shoes. Traction like any other shoe characteristic must be commensurate and balanced with the sport. The equal and opposite force does not necessarily travel back up your leg. The surface itself absorbs a portion of the force converting it to other forms of energy. Subsequently, tennis court surfaces are rated not only for pace but also for the percentage of force reduction.
An analysis of Factorial structure of Kinematic variables in Bowling
Lee, Kyung-Il ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 381~392
DOI : 10.5103/KJSB.2002.12.2.381
This study attempted to indentify changeability of the factorial structure of kinematic analysis in bowling. Subjects of group composed of three groups : Higher bowers who are national representative bowers with 200 average point and one pro-bowler. Middle bowlers who are three common persons with 170 average points. Lower bowler who are three common persons with 150 average points. Motion analysis on throw motion in three groups respectively has been made through three-dimension cinematography using DLT method. Two high-speed video camera at operating 180 and 60 frame per secondary. T-test factorial structure analysis has been used to define variable relations. It was concluded that : 1. The difference of x1, x2, x4, x8, x9, x11, x12, x13 where significant between two group. 2. The difference of number of spin and angle of the back-hand where statistically significant between two group(p<.001, p<.05) 3. The correlation over r=.5 between the kinematic data x1, x2, x3, x9, x10, x11. In the rotation loading matrix Factor 1 was x1, x2, x9, x10 and Factor 2 relates to x3, x11. 4. In order to obtain the factor score as follow as ; Factor 1 = (0.248)X1 + (0.265)X2 + (-0.074)X3 + (0.259)X9 + (0.259)X10 + (-0.025)X11 Factor 2=(-0.016)X1 + (-0.055)X2 + (0.84)X3 + (-0.013)X9 + (-0.007)X10 + (0.553)X11.
Weightlessness in Water : Its Unexpected Mechanical Effects on Freestyle Swimming
Yanai, Toshimasa ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 393~405
DOI : 10.5103/KJSB.2002.12.2.393
When our body is immersed in water, we experience weightlessness. The degree of weightlessness that we experience varies depending on the proportion of the body immersed in water, being governed by the relationship between the weight of body and the buoyant force acting on the body. Human body during the performance of swimming in no exception to these influences. Swimmers body is subject to a time and position dependent force system. Even the magnitude of the buoyant force acting on the swimmers body at every given instant and the corresponding position of the CB change continuously. The findings of this study support the following conclusions. The buoyancy torque was the primary source of bodyroll exhibited by front crawl swimmers performing at distance pace, accounting for 88 % of the bodyroll. Faster swimmers used buoyancy more effectively to generate bodyroll, partially supporting the postulation that an effective use of buoyancy for bodyroll may reduce the generated hydrodynamic forces to be wasted in non-propulsive directions and maximize forward propulsion.
The role of research in the creation of athletic footwear
Lafortune, Mario A. ;
Korean Journal of Sport Biomechanics, volume 12, issue 2, 2002, Pages 407~415
DOI : 10.5103/KJSB.2002.12.2.407
Athletic products must meet the needs of athletes and the demands imposed by sports through innovative design. These needs of athletes and requirements of sports are performance, protection and comfort related. In depth knowledge of anatomy and physiology, etiology of commonly reported injuries, and lower extremity mechanics form the basis of product creation/engineering. Game analysis which entails time and frequency surveys of the skills performed during a game, interviews with athletes and coaches, and discussions with medical staffs are used to identify the skills that are critical to the needs of athletes. In lab full biomechanical analyses of these skills and/or physiological responses of the athletes lead to clear functional criterions that serve as guidelines to be met by the design team. The concepts created by the design team are in turns subjected to the same battery of biomechanical analyses. The learning gathered through this pluridisciplinary process is used to further evolve design concepts. The evolution-testing loop is repeated until biomechanical and/or physiological, mechanical and perceptual tests indicate that the design concept meets the established functional design criterions. At that time, the design concepts is ready for manufacturing research and development. Additional biomechanical and physical tests are performed through that phase to confirm that the manufacturing processes preserve the functionality of the design concept. Durability and long term performance of production samples are evaluated through a final three month long weartest program. A rigorous research/testing program is crucial to create and engineer sport products that meet the performance, protection.