Go to the main menu
Skip to content
Go to bottom
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 23, Issue 4 - Dec 2013
Volume 23, Issue 3 - Sep 2013
Volume 23, Issue 2 - Jun 2013
Volume 23, Issue 1 - Mar 2013
Selecting the target year
Successful Factor Analysis of 540° Dwihuryeochagi to Apply Free Style Poomsae of Taekwondo
Yoo, Si-Hyun ; Ryu, Ji-Seon ; Park, Sang-Kyoon ; Yoon, Suk-Hoon ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 285~294
DOI : 10.5103/KJSB.2013.23.4.285
The purpose of this study was to provide fundamental information for success factors of techniques through kinematic analysis including coordination of lower extremities and landing stability according to the success and failure of
Dwihuryeochagi in Taekwondo. Twenty Taekwondo athletes: ten success group (S, age:
cm, body mass:
kg) and ten failure group (F, age:
cm, body mass:
kg) participated in this study. Three-dimensional motion analysis using a system of 3 video cameras with a sampling of 60 fields/s was performed during the competition of
Dwihuryeochagi. Motions were divided into five events: pivot foot landing (E1), pivot foot toe off (E2), COM max height (E3), kick impact (E4) and landing (E5). At E1, the stride width was greater for S than for F (p<.05) while the time was greater for S than for F during P4 (p<.05). At E4, knee angle was greater for S than for F (p<.05). At E5, hip angle was greater for S than for F (p<.05) while kick distance was greater for S than for F (p<.05). Furthermore, at P3, the time would be related to kicking velocity (p<.05), while at P4, the time, range of hip angle and knee angle would be related to kick distance (p<.05). At P1, COM horizontal velocity would be related to COM vertical velocity of P1 and P2 (p<.05). Based on the findings, success factors of
Dwihuryeochagi were COM horizontal velocity of P1, COM vertical velocity of P2, the time, kick distance, velocity, angle of lower extremities and coordination of P3-P4.
The Analysis of Kinematic Difference in Glide and Delivery Phase for the High School Male Shot Putter's Records classified by Year
Park, Jae-Myoung ; Chang, Jae-Kwan ; Kim, Tae-Sam ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 295~306
DOI : 10.5103/KJSB.2013.23.4.295
The purpose of this study was to provide high school male shot putters training methods of gliding and delivery motion through comparative analysis of kinematic characteristics. To accomplish this purpose, three dimensional motion analysis was performed for the subjects(PKC, KKH, YDL) who participated in high school male shot putter competition on 92nd (2011), 93rd (2013) National Sports Festival. The subjects were filmed by four Sony HXR-MC2000 video cameras with 60 fields/s. The three-dimensional kinematic data of the glide, conversion and delivery phase were obtained by Kwon3d 3.1 version. The data of the shoulder rotational angles and projection angles were calculated with Matlab R2009a. The following conclusions had been made. With the analysis of the gliding and stance length ratio, the gliding length was shorter at the TG than the SG with short-long technique but the gliding and stance length ratio was 46.8:53.2% respectively. The deviation of the shots trajectory from APSS(Athlete-plus-shot-system) revealed that the PKC showed similar to "n-a-b-c-I" of skilled S-shape type, KKH and YDL showed "n-a-d-f-I'" of unskilled type. Furthermore, they showed smaller radial distance from the central axis of the APSS and the shots were away from the linear trajectory. From this characteristics, The PKC who performed more TG than SG had shorter glide with S-shape of APSS(skilled type) showed the better record than others with technical skill. But KKH and YDL had bigger glide ratio with "n-a-d-f-I'" of unskilled type and improved their records with technical factor. The projection factor had an effect on the record directly. Because PKC maintained more lower glide and transition posture with momentum transfer through COG's rapid horizontal velocity respectively the subject possessed the characteristics of high horizontal and vertical velocity with large turning radius from shot putter to APSS.
A Kinematic Analysis of Glide Kip Motion on the Uneven Bars
Kim, Seung-Kwon ; Kim, Seoung-Eun ; Jang, Dae-Sun ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 307~318
DOI : 10.5103/KJSB.2013.23.4.307
The purpose of this study was to analyze the kinematic variables of glide kip motion on the uneven bars through a two-dimensional cinematography. Three expert female gymnastics players were involved in the data gathering process. The followings were concluded according to the results. The arm, trunk and leg segments were fully extended throughout the kip movement. The whole body center of gravity showed the biggest changes during 66 to 87% of the kip motion. During the kip phase, the horizontal displacement of the leg was greater than the vertical displacement the leg. Glide kip motion should be done in orders of upward movement of leg, forward movement of leg, upward movement of trunk and forward movement of trunk segment. It was found that trunk segment and hip joint movements showed bigger changes than those of leg segment and shoulder joint in the glide kip motion. The largest angular velocity of hip joint was shown in the middle of the kip Phase. In conclusion, effective kip movement could be resulted when the trunk was displaced posterior-upward direction with fast hip joint extension after the leg segment was elevated upward and thrusted forward in advance.
Kinematic Characteristics according to Types of Putter Head on Pro Golfer's 4 Meter Putts
Lee, Geun-Hyuk ; So, Jae-Moo ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 319~326
DOI : 10.5103/KJSB.2013.23.4.319
The objective of this study is to help golfers to select adequate putters and to provide golfers basic scientific data for improving athletic performance by showing differences of kinematic variables according to the shape of putter head. In this research three right-handed male pro-golfer who are listed at KPGA were studied and three video camera (GR-HD1KR, JVC, Japan) were used and recording speed was 60 frame/sec during the research. In this study kinematic variables were calculated using Kwon3D XP program and analysed on the 4 events and 3 phases. This study showed the following results : (1) The swing of heel-toe putter showed longer time than that of face balanced putter, and there are statistical significant difference of kinematic variables of each objective (2) As of the trajectory of putter head, heel-toe putter showed more approximating curve trajectory than that of in-between, face balanced putter on the X-axis (3) heel-toe putter showed longer distance follow-through than that of other putters by statistically significant difference on the Y-axis (4) Heel-toe putter showed longer distance swing trajectory over the ground than that of other putters by statistically significant difference on the Z-axis.
Effects of Different Types of Attentional Focus on Dart Throwing Mechanics
Kim, Hye-Ree ; Kong, Se-Jin ; Kim, Soo-Yeon ; Lee, Ki-Kwang ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 327~333
DOI : 10.5103/KJSB.2013.23.4.327
The purpose of this study was to investigate the effects of different types of attentional focus(internal focus vs. external focus) on the dart throwing mechanics. Seven expert dart throwing athletes were assigned to an internal focus group and other seven athletes were assigned to an external focus group. Each group was asked to throw dart either under verbal instruction or without instruction. During dart throwing, accuracy(radial error), consistency(bivariate variable error), dart velocity, acceleration, elbow joint ROM, elbow joint angular velocity, EMD(electromechanical delay), iEMG of biceps brachii and triceps brachii, and CI(coactivation index) were collected and analyzed. Nither instruction type nor instruction itself affected in accuracy and consistency. However, in dart velocity and acceleration, there was an interaction between instruction and attentional focus types. Velocity and acceleration increased in the internal condition, where as they decreased in the external condition. The ROM of elbow joint did not affected by instruction and attention type. However, similar to dart velocity and acceleration, angular velocity increased in internal focus group, while it decreased in external focus group. EMG showed no difference with any condition. In conclusion, internal focus is better than external focus for dart throwing.
Effects of Foot Type and Ankle Joint Fatigue Levels on the Trajectories of COP and COM during a Single-Leg Stance
Shin, Young-Hwa ; Youm, Chang-Hong ; Son, Min-Ji ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 335~345
DOI : 10.5103/KJSB.2013.23.4.335
The purpose of this study was to investigate the effects of foot type and ankle joint fatigue levels on the trajectories of center of pressure and center of mass during a single-leg stance. The study subjects included 24 healthy women (normal foot group, n=10; pronated foot group, n=14). Ankle joint muscle fatigue was induced by using an isokinetic dynamometer, where the fatigue levels were measured on plantar flexion and dorsiflexion at angular velocities of
at 50% and 30% of the peak torque of ankle plantar flexion. Following assessments in the anteroposterior direction according to the level of fatigue, the pronated foot group showed decreased single-leg stance ability at 50% and 30% of the fatigue level. Moreover, the normal foot group showed better single-leg stance ability than the pronated foot group at 30% of the fatigue level. Following assessments in the mediolateral direction, we noted that the single-leg stance ability did not differ significantly according to the levels of fatigue or foot type. In conclusion, ankle plantar flexion at 50% and 30% of the peak torque reduced the ability of the pronated foot group to achieve a single leg stance in the anteroposterior direction. Moreover, the normal foot group showed better single-leg stance ability than the pronated foot group.
Biomechanical Effects of Wearing Mouthguards during Drop Landing
Chae, Woen-Sik ; Lee, Kyu-Bok ; Jung, Jae-Kwang ; Lee, Haeng-Seob ; Kim, Dong-Soo ; Jung, Jae-Hu ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 347~355
DOI : 10.5103/KJSB.2013.23.4.347
The purpose of this study was to determine the biomechanical effect of wearing the mouthguard on the lower limb during drop landing. Nine male university students who have no musculoskeletal disorder were recruited as the subjects. Linear velocity, angular velocity, vertical GRF, loading rate, joint moment, and lower extremity muscle activity were determined for each subject. For each dependent variable, paired t-test was performed to test if significant difference existed between with mouthguard (WM) and without mouthguard (WOM) conditions (p<.05). The results showed that linear velocity, angular velocity, vertical GRF and loading rate were no significant difference between the two groups. The inversion moment of the ankle joint was increased in WM compared to WOM. Average IEMG values from BF, TA, and LG in WM were significantly greater than corresponding values in WOM during IP phase. This indicates that wearing mouthguard played a vital role in muscle tuning for maintaining joint stability of the lower limb and preventing injury.
Characteristics of the Compensation for Gait of the Induced Knee Stiffness in Normal Subjects
Woo, Byung-Hoon ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 357~367
DOI : 10.5103/KJSB.2013.23.4.357
The purposes of this study were investigated physical compensation for gait on induced knee stiffness in normal subjects. Ten subjects were participated in the experiment(age:
kg). The study method adopted 3D analysis with five cameras and ground reaction force with two force-plate. Induced knee stiffness level were classified as gait pattern on ROM of knee(free level,
restriction level, fix level). The results were as follows; In angular displacement of hip joint, left hip joint was the more extended in mid-stance on induced right knee stiffness. In angular displacement of knee joint, there was no physical compensation on induced right knee stiffness, but free knee level gait was more flexed in swing phase of right knee joint. In angular displacement of ankle joint, right ankle joint was the more dorsiflexed on induced right knee stiffness, and
restriction level and fix level gait were less plantarflexed in TO2. In trunk tilt, free and
restriction level gait was more backward tilt on induced right knee stiffness. In ROM of each joint, right knee joint was more larger and trunk tilt was more lower on induced right knee stiffness. In GRF, Fx was more bigger lateral force in free and
restriction level gait, and was more bigger medial force in fix level gait. Fy was more bigger propulsion force in free level gait, and was was more bigger braking force in
restriction level gait. Left braking force in
restriction level gait was more bigger. Fz was no significant.
Kinematic Analysis of Dynamic Stability Toward the Pelvis-spine Distortion during Running
Park, Gu-Tae ; Yoo, Kyoung-Seok ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 369~376
DOI : 10.5103/KJSB.2013.23.4.369
The purposes of this study were to assess dynamic stability toward pelvis-spine column distortion during running and to compare the typical three-dimensional angular kinematics of the trunk motion; cervical, thoracic, lumbar segment spine and the pelvis from the multi-segmental spine model between exercise group and non-exercise group. Subjects were recruited as exercise healthy women on regular basis (group A, n=10) and non-exercise idiopathic scoliosis women (group B, n=10). Data was collected by using a vicon motion capture system (MX-T40, UK). The pelvis, spine segments column and lower limbs analysiaed through the 3D kinematic angular ROM pattern. There were significant differences in the time-space variables, the rotation motion of knee joint in lower limbs and the pelvis variables; obliquity in side bending, inter/outer rotation in twisting during running leg movement. There were significant differences in the spinal column that is lower-lumbar, upper-lumbar, upper-thoracic, mid-upper thoracic, mid-lower thoracic, lower thoracic and cervical spine at inclination, lateral bending and twist rotation between group A and group B (<.05, <.01 and <.001). As a results, group B had more restrictive motion than group A in the spinal column and leg movement behaved like a 'shock absorber". And the number of asymmetry index (AI) showed that group B was much lager unbalance than group A. In conclusion, non-exercise group was known to much more influence the dynamic stability of equilibrium for bilateral balance. These finding suggested that dynamic stability aimed at increasing balance of the trunk ROM must involve methods and strategies intended to reduce left/right asymmetry and the exercise injury.
Biomechanical Analysis of the Non-slip Shoes for Older People
Lee, Eun-Young ; Sohn, Jee-Hoon ; Yang, Jeong-Hoon ; Lee, Ki-Kwang ; Kwak, Chang-Soo ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 377~385
DOI : 10.5103/KJSB.2013.23.4.377
Fall is very fatal accident causes death to older people. Shoe may affect to fall. Shoe influences risk of slips, trips, and falls by altering somatosensory feedback to the foot. The purpose of this study was to investigate the analysis of non-slip shoes for older people and influence on older people's lower extremity. For this study twenty three healthy older people were recruited. Each subjects walked over slippery surfaces (COF 0.08). Four pairs of non-slip shoes (shoe A had the greatest COF, 0.23 while shoe B, C, and D had smaller COF relatively) for older people were selected and tested mechanical and biomechanical experiment. For data collection motion capture and ground reaction forces were synchronized. There were statistically significant differences for slip-displacement, coefficient of friction, braking force, propulsion force, knee range of motion and knee joint stiffness by shoes. It was concluded that shoe A was the best for non-slip function because of the lowest slip displacement, the highest braking and propulsion forces, and the highest mechanical and biomechanical coefficient of friction where as shoe B, C, D were identified as a negative effect on the knee joint than shoe A. To prevent fall and slip, older people have to take a appropriate non-slip shoes such as shoe A.
Kinematic Characteristics in Female Pro Golfers' swings Intended to Increase Driving Distance
Park, Hye-Lim ; Kim, Jai-Jeong ; So, Jae-Moo ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 387~393
DOI : 10.5103/KJSB.2013.23.4.387
The purpose of this study was to investigate the difference of kinematic factors acting in the body during a normal swing and a swing taken with an intention to increase driving distance by female pro golfers. Female pro golfers may increase driver clubhead speed and improve driving distance through maintaining a large X-factor angle during backswing and delaying the uncocking period by rapidly shifting the weight to the left foot during downswing.
Change of Mechanical Energy before and after Training of Half Vinyasa Yoga - Energy Contribution of Body Segments and Correlation between Maximum COG and Segmental Energy -
Yoo, Sil ; Hah, Chong-Ku ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 395~402
DOI : 10.5103/KJSB.2013.23.4.395
The purpose of this study was to investigate change of mechanical energy before and after training of half vinyasa yoga. Thirteen subjects (height:
cm, body mass:
yrs) participated in this experiment. The motions of half vnyasa yoga were captured with Vicon system and parameters were calculated with Visual-3D. After training of half vinyasa yoga, the mechanical energies of body segments were increased and increments of mechanical energies in the lower segments were greater than the upper segments. The phase increments of mechanical energies increased phase 1, phase 2, and phase 3 in order. After training of half vinyasa yoga, phase contributions of body segments were similar before training of half vinyasa yoga. The contribution of mechanical energy on trunk segment in body was the greatest contribution of upper segments; also that of mechanical energy on thigh segment in body was the greatest contribution of lower segments. Before training, the coefficient of correlation between vertical center of gravity (CoGz) and mechanical energy of phase 3 was a -.559, but after training, the coefficient of correlation between CoGz and mechanical energy of phase 2 was a .587. These findings suggest that the training of half vinyasa yoga may be increasing the mechanical energies of body segments.
A Comparative Study on Orientation density to the Front and Path Length of Rotational Axis with/without Music during Fouette Turns
Cho, Nam-Gyu ; Oh, Seong-Geun ; Shin, Hwa-Kyung ; Park, Jae-Keun ; Lee, Seung-Yon ; Ki, Jae-Seok ; Hah, Chong-Gu ;
Korean Journal of Sport Biomechanics, volume 23, issue 4, 2013, Pages 403~407
DOI : 10.5103/KJSB.2013.23.4.403
turns are repeated pirouettes which begin as a normal pirouette en dehors but include a movement that allows the rotational momentum lost to friction to be regained once each revolution. The purpose of this study was to investigate on orientation density of head/trunk to the front with and without music to which dancers perform the Fouette turn in time. 10 female dancers(
years old, height;
kg) who are the students of S University participated in this study. It took shorter time to perform one revolution of fouette turn with music (930 ms) than without music (961 ms), which reason may be the shorter time of phase 2 in which the rotational momentum is not produced but lost to fiction. Orientation density of trunk to the front was smaller with music (.176) than without music (.196), while the one of head had not significant difference between with and without music. And the path length of marker on
left metatarsal bone during one revolution was smaller with music (35.7 cm) than without music (40.2 cm) but the difference was not statistically significant (p=.267).