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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Korean Journal of Sport Biomechanics
Journal Basic Information
Journal DOI :
Korean Society of Sport Biomechanics
Editor in Chief :
Volume & Issues
Volume 14, Issue 3 - Dec 2004
Volume 14, Issue 2 - Aug 2004
Volume 14, Issue 1 - Apr 2004
Selecting the target year
Kinematic Analysis of the Linking Motion from the Swallow Skill to the Nakayama Skill on the Rings
Chung, Nam-Ju ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 1~14
DOI : 10.5103/KJSB.2004.14.2.001
This study was intended to contribute to allowing athletes to raise a technical understanding of two motions of high difficulty such as the Swallow motion and the Nakayama motion and enhance their competitive power by analysing the kinematical factors required to link those two motions on the competitive scene on the rings for current national athletes. For this purpose, the game of the ring event was videotaped for male heavy gymnasts participating in the final elimination match of the 2004 Athens Olympic Games. This study attempted to select the performing motions of the final 1st-and 2nd-place athletes performing the linking motions from the Swallow motion and the Nakayama motion using the DLT(direct linear transformation) method. As a result, it arrived at the following conclusion : A1 properly performed the flexing and extending movements using the angular velocity of the segment and joint as the switching motion using the body at the time of linking the motion from the Swallow skill to the Nakayama skill. A2 was evaluated to perform the skill taking the form of depending on the force at the static state. Therefore, it is thought that A1 should take care of shaking at the time of using the elasticity of the body. It is thought that in case of A2 the proper use of the elasticity of the body take care of shaking at the switching motion while taking advantage of the force will contribute to his competitive power.
The Kinematic Analysis of Peters Motion on Parallel bars
Yoon, Hee-Joong ; Yoon, Chang-Sun ; Kim, Tae-Sam ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 15~26
DOI : 10.5103/KJSB.2004.14.2.015
The purpose of this study was to investigate the kinematic variables of peters motion in parallel bars. The subjects were 3 male national gymnasts. For this study, kinematic data were collected using video camera. Coordinate data were low-pass filtered using a fourth-order Butterworth with cutoff frequency of 6Hz. Each valuables analyzed was used to compare kinematic features between the subjects. The conclusions were as follows; 1. For a stable regrasp motion, the subjects appeared to increase horizontal and vertical displacement during the DS phase because it induce a vertical elastic of body and reaction of bar for the US phase. 2. For a stable hand standing motion of the regrasp, the subjects appeared to maintain the fast vertical and horizontal velocity during the DS phase, but in contrary during the US and Air phase the vertical and horizontal velocity appeared to do decrease. 3. When the arm lean angle and the trunk lean angle maintain a big angle during the DS phase, the subjects appeared to do a stable performance to release in a high position.
Kinematic Analysis on Giant Swing Backward to Handstand on Parallel Bars
Ahn, Wan-Sik ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 27~40
DOI : 10.5103/KJSB.2004.14.2.027
The objective of this study is to identify the kinematic variables of giant swing backward to handstand as well as individual variations of each athlete performing this skill, which in turn will provide the basis for developing suitable training methods and for improving athlete`s performance in actual games. For this end, 3 male athletes, members of the national team, who are in
University, have been randomly chosen and their giant swing backward to handstand performance was recorded using two digital cameras and analyzed in 3 dimensional graphics. This study came to the following conclusion. 1. Proper time allocation for giant swing backward to handstand are: Phase 1 should provide enough time to attain energy for swing track of a grand round movement. The phase 3 is to throw the body up high in the air and stay in the air as long as possible to smoothen up the transition to the next stage and the phase 4 should be kept short with the moment arm coefficient of the body reduced. 2. As for appropriate changes of locations of body center, the phase 1 should be comprised of horizontal, perpendicular, compositional to make up a big rotational radius. Up to the Phase 3 the changes of displacements of vertical locations should be a good scale and athlete`s body should go up high quickly to increase the perpendicular climbing power 3. When it comes to the speed changes of body center, the vertical and horizontal speed should be spurred by the reaction of the body in Phase 2 and Phase 3. In the Phase 4, fast vertical speed throws the body center up high to ensure enough time for in-the-air movement. 4. The changes of angles of body center are: in Phase 2, shoulder joint is stretching and coxa should be curved up to utilize the body reaction. In the Phase 4, shoulder joint and coxa should be stretched out to get the body center as high as possible in the air for stable landing. 5. The speeds of changes in joints angles are: in the Phase 2 should have the speed of angles of shoulder joints increase to get the body up in the air as quickly as possible. The Phase 3 should have the speed of angles in shoulder joint slow down, while putting the angles of a knee joint up to speed as quickly as possible to ensure enough time for in-the-air movement.
A Kinematic Analysis of Snatch Technique in Weight-Lifting
Moon, Young-Jin ; Song, Joo-Ho ; Kim, Ji-Seob ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 41~55
DOI : 10.5103/KJSB.2004.14.2.041
This study analyzed snatch technique in weight-lifting performed by female gold, silver, and copper medalists at the 75kg level in the 2002 Pusan Asian Games and obtained the following conclusions. 1. KSH used more extensor in the waist than those in ankles, knees, or hip joints during the second pull, So further training is required to manifest both each of joints and waist extensor effectively and thus for the line from shoulders through barbell to hip joints to form a smooth vertical pattern. 2. Contrary to those in other countries, Korean athlete KSH tended to be swift in starting but slow in the second pull section, showing less effectiveness in movement during the second pull; therefore, they must try to exert a swift movement in lockout. 3. KSH showed slowdown in the speed, which was a factor interfering with performance during second pull, despite the great maximum speed of moving barbell. It is important to use barbell sufficiently not to reduce the speed of vertical movement but rather to keep the speed increasing. 4. KSH, who kept doing inefficient movements such as failure to perform swift lockout after lifting the heel at the maximum angle of lower limbs, needs to reduce this meaningless extension of ankles, knees, or hip joints to exert energy effectively.
Evaluation of the Impact Force on the Vertically Placed Force Platform
Choi, Chi-Sun ; Shin, In-Sik ; Seo, Jung-Suk ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 57~68
DOI : 10.5103/KJSB.2004.14.2.057
This study was to evaluate the consistency of the vertical force(
) of the force platform and the impact force. Two experiments were performed. First, the force platform was vertically placed to hang to the wall. While the rotating iron body hit the force platform,
was measured. Then
was compared with the impact force of the rotating iron body that was precalculated by using the inertia moments and the rotating force. Second, six Taekwondo masters punched the force platform to show what a certain pattern the impart force has. They were asked to punch the target depending on target distances. The target distances were differed from the relative arm segment of subjects as 90%, 80%, 70%, 60%, and 50% (100% target distance equals the aim length of each subject). Pearson`s correlations were used between
and the impact force. Also the linear regression was also performed to show the linearity. At the first experiment,
and the impact force had much correlations and showed linear characteristics. Therefore,
could be regarded as the impact force. At the second experiment, the strongest impact force was measured at the target distance of 80% and the time taken to the maximum impact force was within 0.02 seconds. The result of this study recommends that it can help the comparative study between the impact forces and other hitting sports.
The Effect of snatch technique improvement for men weightlifter of feedback support through quantity analysis by periods
Moon, Young-Jin ; Ryu, Jung-Hyun ; Lee, Soon-Ho ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 69~83
DOI : 10.5103/KJSB.2004.14.2.069
The purpose of this study is searching for technical merits and demerits of each weight lifting player through qualitative motion analysis system. Moreover, It is also analysis the repeating the establishment of exercise purpose and studying for the effect of the field adaptation. The subject of this study was five male weight lifting players who have been engaged in Korean Delegation Team. The institution of exercise target was made through two times qualitative analysis and the result of studying for the effect of the field adaptation was produced before offering feedback. Moreover, two time analysis added after offering feedback. All analysis was based on 2-D visual analysis. The results of this study are as follows: 1. Maximal barbell moving speed in starting phase was decreased after offering feedback. This result implies advancement of technical skills after offering feedback. 2. From starting posture to 앉아받기, forward and backward moving distance of hip joint was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 3. In terms of pull phase, forward and backward moving distance of hip and shoulder joint was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 4. In terms of pull phase, the difference of horizontal value of coordinates was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 5. In terms of pull phase, the motion range of hip joint was decreased after offering feedback in three of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them were not variable or narrow decreasing. This result represents that feedback system could not brought tremendous effects. 6. From apex point of barbell to 앉아받기, the difference of barbell height was decreased after offering feedback in three of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them weren`t variable or narrow increasing. This result represents that feedback system could not brought tremendous effects. 7. In terms of last-pull phase, the angular velocity of knee joint was increased after offering feedback in four of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them, only one subject, decreased. This result represents that feedback system could not brought tremendous effects. 8. In terms of last-pull, the conversional tendency of maximal extension to flextion came out all but simultaneously without offering feedback in four of five subjects. This is well-performed technique. Only one subject, however, could not use power effectively because the fact that his maximal extension came out in serial, from ankle to knee and waist means dispersion of power. In addition to, after offering feedback, only one subject made increasing the maximal extension of knee in last-pull and this result represents advancement of skills after offering feedback. However, the rest of them could not make meaningful development after offering feedback. 9. It might be assumed that searching for technical merits and demerits of each weight lifting player through qualitative motion analysis system could improve player`s skill.
The Influence of Midsole Hardness of Running Shoes on Shoes Flex Angle during Running
Mok, Seung-Han ; Kwak, Chang-Su ; Kwon, Oh-Bok ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 85~103
DOI : 10.5103/KJSB.2004.14.2.085
This study was conducted to determine what effects would the midsole hardness of running shoes have on shoe flex angle and maximum propulsive force. Furthermore, the relationship between the shoes flex angle and maximum propulsive force was elucidated in order to provide basic data for developing running shoes to improve sports performances and prevent injuries. The subjects employed in the study were 10 college students majoring in physical education who did not have lower limbs injuries for the last one year and whose running pattern was rearfoot strike pattern of normal foot. The shoes used in this study had 3different hardness, shore A 40(soft), 50(medium) and 60(hard). The subjects were asked to run at a speed of
, and their movements were videotaped with 2 S-VHS video-cameras and measured with a force platform. And the following results were obtained after analyzing and comparing the variables. 1. Although the minimum angle of shoes flex angle was estimated to appear at SFA4, it appeared at SFA2 except in those shoes with the hardness of 40. 2. The minimum angle of shoes flex angle was
with barefoot. Among the shoes with different hardness, it was the smallest when the hardness was 50 at
. The time to the minimum angle was 70.7% of the total ground contact time. 3. Maximum propulsive force according to midsole hardness was the largest when the hardness was 50 at
. There was a low correlation between maximum propulsive force and shoes flex angle.
In-shoe Loads during Treadmill Running
Lee, Ki-Kwang ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 105~119
DOI : 10.5103/KJSB.2004.14.2.105
To enhance our understanding of the loads on the foot during treadmill running, we have used a pressure-sensitive insole system to determine pressure, rate of loading and impulse distributions on the plantar surface during treadmill running, both in minimally cushioned footwear and in cushioned shoes. This report includes pressure, rate of loading, impulse and contact time data from a study of ten subjects running on a treadmill at 4.0m/s. Among heel-toe runners, the highest peak pressures and highest rates of loading were observed under the centre of the heel and in the medial forefoot. The arch regions were only lightly loaded. Contact time was greater in the forefoot than in the heel. Two-thirds of the impulse recorded during the step was the result of forces applied through the forefoot, mostly in the region of the metatarsal heads. The distribution of loads in the shoe suggests that the load distributing properties of the cushioning system are most important in the centre of the heel, under the metatarsal heads and great toe. Shock attenuation is primarily required under the centre of the heel and to lesser extent under the metatarsal heads. Some energy dissipation may be desirable in the heel region because it causes shock to be absorbed with less force. All the `propulsive` effort is applied through the forefoot. Therefore, this region should as resilient as possible.
Rotational Friction of Different Soccer Stud
Lee, Joong-Sook ; Park, Sang-Kyun ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 121~138
DOI : 10.5103/KJSB.2004.14.2.121
The design of soccer studs is important for providing friction on a variety of surfaces. We hypothesized that a certain type of soccer studs could improve performance due to high rotational friction. Thus, this study was conducted to determine the relationship between the frictional characteristics and different soccer stud design. Twelve recreational soccer players were recruited. Rotational friction data from the force plate was collected for all subjects during normal walking with 180 degree rotation. Walking speed was controlled at 1.2m/s (
) with timing lights on infilled artificial turf. Three different types of soccer studs and one running shoe were tested. Repeated measures ANOVA was used to determine significance. Significant differences were found in rotational friction with four different shoes. Trx and World studs tended to have greater maximum rotational friction than the running shoe (Nova) and traditional soccer shoe(Copa Mondial). The results were as follow : world(25.95Nm) > trx(25.74Nm) > copa(22.50Nm) > nova(16.36Nm). The difference may be due to the number, location, size, and shape of studs. We concluded that stud design influences rotational friction between the shoe and surface during movement. Based on studs design and contact area, Trx with blade type studs are recommended since it showed high rotational friction for performance as well as enough contact area for stability. However, differences due to the mechanical properties of soccer studs are still being investigated.
Countermovement of the Segments During the Tae-kwon-do Roundhouse Kicking
Hwang, In-Seong ; Lee, Sung-Cheol ; Lim, Jung ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 139~152
DOI : 10.5103/KJSB.2004.14.2.139
Two subjects, an expert and a novice, were carefully selected based upon their foot speed. Three dimensional videography was used in the assessment of roundhouse kicking of the Tae-kwon-Do. The local reference frames were imbedded at the trunk, pelvis, thigh and shank. Anatomical angular displacement at the joints were measured by projecting the upper segment`s local axes to the lower segment`s local reference planes. The local axes again projected to the global reference frames and absolved each segment`s movement. The peaks of the anatomical angular displacement curve assessed as the countermovements and the angular movements of the segments in the global space absolved in light of the occurrence of the countermovements. The expert showed larger and more countermovements than the novice at the all segments. The counterrnovement occured more clearly at the trunk than the hip and knee joint and during the preparative movement phase. These countermovements occurrence were due to either by turning upper or lower segments and controlled by the turning direction and sequence of the two nearby segments. It was revealed that the countermovements of the trunk during the preparative movement phase was the important factor of the power kicking.
Comparison of the kinematic analysis of grand battement Jeté á la seconde in center between skilled and unskilled ballet majors
Youm, Chang-Hong ; Park, Young-Hoon ; Seo, Kook-Woong ; Yang, Chung-Mo ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 153~166
DOI : 10.5103/KJSB.2004.14.2.153
The purpose of this study was to investigate time of the phase, angle of the right ankle, knee, and hip joint, lateral angle of the trunk, mediolateral displacement of COM, and vertical displacement of COM between two groups while executing grand battement
la seconde in a center exercise setting through 3D video analysis. The subjects participated in this study were skilled and unskilled 6 female ballet majors in Busan, respectively. The conclusions are as follows: 1. The time of the phase 2 was faster than P3. It shows a significant difference(p<.05) for P1 and P4 between skilled and unskilled groups 2. The angle of He right ankle joint has a significant difference(p<.05) at E4 between skilled and unskilled groups. The angle of the right knee joint has no significant difference at all events between skilled and unskilled groups. The angle of the right hip joint has a significant difference(p<.001) at E3 between skilled and unskilled groups. 3. The lateral angle of the trunk has a significant difference(p<.05) at E1 and at E5 between skilled and unskilled groups. The skilled group of the lateral angle of the trunk was lower than the unskilled group. However the skilled group`s lateral angle of the trunk was bigger than the unskilled group at E3. It has significant difference(p<.001) at E3 between skilled and unskilled groups. 4. The mediolateral displacement of COM has no significant difference at all events between skilled and unskilled groups. The vertical displacement of COM has a significant difference(p<.01) at E3 between skilled and unskilled groups.
The Analysis of Electromyography during Professional & Amateur Golfer`s Iron Swing
Park, Jong-Rul ; Park, Bum-Young ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 167~178
DOI : 10.5103/KJSB.2004.14.2.167
The purpose of this study was to describe and compare the selected electromyographical muscle activities of trunk and hip during Professional and Amateur golfer`s Iron swing. Using surface electromyography, we evaluated muscle activities in 6 male professional golfers and 6 male amateur golfers during the golf iron swing. Surface electrodes were used to record the level of muscle activity in the right abdominal oblique, left abdominal oblique, right erector spinae, left erector spinae, right rectus abdominis, left rectus abdominis, right gluteus maximus, left gluteus maximus muscles during the golfer`s swing. These signals were compared with IEMG(Integrated EMG) which was normalized by %RVC(Reference voluntary contraction). The golf swing was divided into three phases: take away, forward swing-acceleration, follow-through. We observed patterns of trunk muscle activity throughout three phases of the golf swing. The results can be summarized as follows: LES(Left Erector spinae) had statistically significant difference in take away and forward swing-acceleration phases. It was showed no significant difference in follow-through phase.
Categorization of two different swing styles using weight transfer patterns of golf swing
Linm, Young-Tae ;
Korean Journal of Sport Biomechanics, volume 14, issue 2, 2004, Pages 179~186
DOI : 10.5103/KJSB.2004.14.2.179