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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 21, Issue 5 - Dec 2011
Volume 21, Issue 4 - Dec 2011
Volume 21, Issue 3 - Sep 2011
Volume 21, Issue 2 - Jun 2011
Volume 21, Issue 1 - Mar 2011
Selecting the target year
Effects of Taekwondo and Walking Exercises on the Double-Leg Balance Control of Elderly Females
Youm, Chang-Hong ; Lee, Joong-Sook ; Seo, Kook-Eun ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 123~129
DOI : 10.5103/KJSB.2011.21.2.123
The purpose of this study was to compare and analyze the effect of twelve-week Taekwondo and walking exercises on the double-leg balance control by dividing elderly females into Taekwondo, walking exercise and control groups. In total, 30 elderly females were randomly divided into Taekwondo, walking exercise, and control groups, with 10 subjects in each group. Subjects participating in this study were 10(age
years) and 10(age
years) in the three groups, respectively. Although the AP measures were not significantly different among the groups and times, the ML RMS distance and ML velocity, among the ML measures showed a significant difference among the groups and times. Average velocity and 95% confidence ellipse area were also significantly different among the groups and times. Twelve-week Taekwondo and walking exercises were found to be effective in improving static balance control. Future studies on the development of a Taekwondo intervention program tailored for the elderly with many subjects conducted by using a long-term training program are expected.
Kinematic Analysis of the Hurdle Clearance Technique used by World Top Class Women's Hurdler
Ryu, Jae-Kyun ; Chang, Jae-Kwan ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 131~140
DOI : 10.5103/KJSB.2011.21.2.131
The purpose of this study was to evaluate the kinematic characteristics of 5th hurdle clearance during the 100m hurdle final competition at the 2010 Colorful DaeGu pre-championship meeting. This study was also intended to provide the technical data for better performance for preparing the 2011 world championship. Lee and Jung need to change technical movement by reducing the distance of the take-off point from the hurdle and by decreasing the vertical velocity of the C.G.(center of gravity) at the takeoff. Powell's angle of the take-off leg showed bigger at the touchdown and smaller at the takeoff comparing to Lee's and Jung's. Furthermore, Powell's horizontal velocity of the C.G. was maintained at the takeoff and touchdown. So, Lee and Jung need to change angle of the take-off leg the same as Powell's. Both Lee and Jung need to increase the angle of landing leg at the touchdown. In addition to increasing the angle Jung needs to improve the knee and ankle velocity with the hurdling leg.
Analysis of Projectile Factors and Biomechanical Characteristics of Men's Hammer Throwing during Turning Phases
Kim, Tae-Sam ; Ryu, Ji-Seon ; Lee, Mi-Sook ; Yoon, Suk-Hoon ; Park, Jae-Myoung ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 141~152
DOI : 10.5103/KJSB.2011.21.2.141
The purpose of this study was to investigate the projectile factors and biomechanical characteristics of men's hammer throwing during turning phases. Four national leveled athletes including Korea national record holder participated in this study. After full warm-up, each participant performed 6 trials of hammer throwing with their best. The best recorded trial was selected from each participant and they were analyzed for this study. Three-Dimensional motion analysis using a system of 5 video cameras at a sampling frequency 60Hz was performed for this study. As the number of turns increased, athletes revealed following characteristics. 1) The single and double support time decreased. 2) The rotation foot was closed to axis foot and it revealed greater medio-lateral displacement than that of horizontal one. 3) At the transition point from double support to single support, ball was in front of rotation foot so that not much angular velocity obtained. For the projectile factors, projectile angle did not show differences while projectile height and velocity revealed differences among the participants. It may indicated that each athlete has different fitness and skill level to resist centrifugal force which become larger as the number of turn increased.
Development and Kinematic Evaluation for Training Method to Strengthen Part Motion of Snatch in Weight Lifting
Moon, Young-Jin ; Kwon, An-Sook ; Lee, Gyee-San ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 153~159
DOI : 10.5103/KJSB.2011.21.2.153
The purpose of this study was to develop an innovative training model and method to improve the posture and motion, while pulling up during weight lifting by evaluating the problems of Korean weight lifters performing this motion. To investigate the effectiveness of the new training method substitute members of the Korean national weight lifting team performed both the original pull up technique and new pulling training technique while kinetics and kinematics were recorded. For this study, the first phase of the new training method is more appropriate than the original training with the pull up drop slow deadlift to the knee joint. For the second phase, the new training motion is deemed to be more effective than the current box deadlift motion. Also, this new motion corrects the posture as there is more anterior hip joint motion(about 10 cm) and the knee flexes to about 120 degrees. For the third phase, starting about 10cm above the knee the box snatch high pull up is identified as a more suitable training method. For the forth phase, the box top snatch method is judged to be a more effective training method than the original top snatch training method.
The Kinematic Difference According to Success and Failure of Shot-Putting - Focusing on Member of the National Team, Hwang, In-sung, Player -
Ryu, Ji-Seon ; Park, Jae-Myoung ; Kim, Tae-Sam ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 161~171
DOI : 10.5103/KJSB.2011.21.2.161
The purpose of this study was to identify biomechanical characteristics of glide and delivery motion of In-Sung Hwang, player who is a member of the national team among the finalists in the men's shot put at the 2010 National Sports Festivals. Three-Dimensional motion analysis using a system of 3 video cameras at a sampling frequency of 60 Hz was performed for this study. During the glide and delivery phase the results showed following characteristics; 1) The glide type was suitable for the short-long technique, but the trajectory of shot at the glide and delivery phase showed a different trajectory pattern with "S-shaped" type of elite players due to many deviating from central axis of the APSS(athletic-plus shot system). 2) Left knee was more flexed during failed trials compared to successful trials but COG was higher. Therefore, the player showed less stability of COG as he may not get enough breaking force at the left foot. 3) Furthermore, it would be required to have strong muscle power at the trunk, throwing arm, and the lower extremity in order to achieve maintain a low projection angle of the release.
The Effect of Asymmetric Muscle Force in the Lower Extremity on Dynamic Balance on during Drop Landing
Kim, Chul-Ju ; Lee, Kyung-Il ; Hong, Wan-Ki ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 173~179
DOI : 10.5103/KJSB.2011.21.2.173
This study aims to analyse difference in biomechanical factors between dominant legs and recessive ones according to muscular imbalance during drop landing targeting talented children in sports. The subjects of the study were ten primary students who are attending to Sports Program for Talented Children organized by C university (age:
m, and weight:
kg). Strength legs were classified into dominant side and strengthless legs were classified into non-dominant legs. For three-dimensional analyses of the data collected, 6 video cameras(MotionMaster200, Visol, Korea) were used. To analyse ground reaction force, two force platforms(AMTI ORG-6, MA) were used and to analyse electromyograghy a 8-channeled wireless Noraxon Myoresearch made in USA was used at 1000 Hz for sampling. As a result, it was discovered that the dominants legs controlled knee bending motions more stably than strengthless legs as the maximum vertical ground reaction force was significantly high in dominant legs(p<.05), and joint moment of knee joints of the dominant legs was high(p<.05). Therefore, this study suggested that injury prevention program focusing on muscular balance as well as the existing sports programs for talented children should be developed based on results of the study and it is expected that the results will be useful for improvement of sports programs for talented children.
Analysis for Angle, Center of Mass and Muscle Activity on Good and Bad Motion of the Pirouette in Ballet
Kwon, An-Sook ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 181~187
DOI : 10.5103/KJSB.2011.21.2.181
The purpose of this study was to identify major factors on pirouette in ballet, and especially angle, Center of Mass(CM) & muscle activity aspects. The data were collected by using Motion Analysis System with 12 cameras to analyze kinematic variables with 120 Hz and Electromyography(EMG; 4,000 Hz) & Force Platform(1,000 Hz) to analyze kinetic variables. The subjects of this study were 8 female ballet dancers. The results as follow. First of all, full extension of knee joint and full plantar flexion of ankle joint appeared at the similar point. Secondly, in the rotational phase, total movement of segments in Good motion is smaller than that of Bad motion(in Good motion, head movement 2.70 cm, right shoulder movement 0.72 cm, left shoulder 4.26 cm, left wrist 17.4 mm smaller than Bad motion). Third, CoP distance of Good motion is 11.76 mm, and CoP distance of Bad motion is 11.76 mm, so Good motion is 5.98 mm smaller). Lastly, Pirouette need more retus femur activity than gastrocnemius activity in extention phase and rotation phase of support leg.
Biomechanical Alternation of the Elderly Depending on the Type of Gait Termination
Yi, Jae-Hoon ; Ryu, Ji-Seon ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 189~196
DOI : 10.5103/KJSB.2011.21.2.189
The purpose of this study was to verify the difference in biomechanical variation and pattern of the lower limb between planned and unexpected termination, which is related to the prevention of fatal fall in the elderly. Therefore, selected twenty subjects for each group which composed of females(age:
cm, body mass:
kg) and women(age:
cm, body mass:
kg) in their twenties. As a result, lower limb's extension moment and power were increased significantly in statistics(p<.05). Also, knee joint power showed instant changes from concentric contraction to eccentric contraction and hip joint power from eccentric contraction to concentric contraction. During unexpected termination there were dramatical increase in eccentric contraction and power(p<.05). In both planned and unexpected termination, ankle joint moment were higher in young group, but the moment of the hip joint were higher in the elderly group(p<.05). In contrast to younger group, there were no changes in knee extension moment in elderly group(p<.05). but showed relatively higher hip joint extension moment and power(p<.05).
The Effects of Landing Height and Distance on Knee Injury Mechanism
Cho, Joon-Haeng ; Kim, Ro-Bin ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 197~205
DOI : 10.5103/KJSB.2011.21.2.197
Various jumping and landing motions are shown during sports event. But most previous studies have not considered landing height and distance simultaneously. The purpose of this study was to identify the effects of landing height and distance on knee injury mechanism. Fourteen male(age:
kg) participated in this study. The subjects attempted drop landing task onto the ground from 30 cm to 45 cm heights and to 20 cm to 40 cm distances. The results were as follows. First, higher drop landing height and longer distance showed greater degree of maximal knee flexion and valgus. Second, higher drop landing height and longer distance showed greater maximal knee extension moment and varus moment. Third, higher drop landing height and longer distance showed larger maximal knee absorption power. Lastly, higher drop landing height showed increased Peak GRF. Landing height was more related to the cause of injury, which was indicated by increased maximal knee extension moment, peak GRF and maximal knee absorption power. Landing distance was also associated with increased knee valgus moment and absorption power during landing. These results suggest that landing height and distance may be the cause of injury.
Changes of Elastic Properties in In Vivo Human Tibialis Anterior Aponeurosis Following Maximum Eccentric Exercise
Jeong, Jin-Young ; Lee, Sung-Cheol ; Lee, Hae-Dong ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 207~213
DOI : 10.5103/KJSB.2011.21.2.207
The purpose of this study was to investigate changes in elastic properties of tendon structure of human ankle dorsiflexor following eccentric exercise. Six male subjects(age:
kg) and three female subjects(age:
kg) performed a single bout eccentric exercise consisting of 120 repetitions of maximum eccentric contractions. Prior to and following the eccentric exercise, isometric ankle dorsiflexion strength along with longitudinal ultrasound image of the tibialis anterior(TA) were collected. Muscle strength decreased about 30% after eccentric exercise. From the muscle strength vs. aponeurosis elongation curve, we obtained an index of stiffness. Stiffness of deep aponeurosis of the TA was assessed and found to be decreased from
N/mm. The results of this study suggest that decrease in stiffness of the TA aponeurosis following eccentric exercise might have significant implications to functions of the muscle-tendon complex and the involved joint motion and provide better understanding of eccentric exercise in the fields of training and rehabilitation.
Biomechanical Analysis on Locomotion with Lower Extremity Supporter
Lee, Kyung-Il ; Hong, Wan-Ki ; Lee, Chul-Gab ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 215~222
DOI : 10.5103/KJSB.2011.21.2.215
The purpose of this study was to analyze the effects of the use of the lower extremity supporter to ground reaction force(GRF) & EMG in women. Five women participated in the experiment conducted in the study(age:
kg, lower extremity height:
cm, knee height:
cm). The Ground reaction force was measured by AMTI ORG-6 and the Muscle activity of the lower extremity was measured by an 8-channel surface EMG system(Noraxon Myoresearch, USA, 1000Hz). We statistically compared muscle activity and ground reaction force with and without the lower-extremity supporter by one-way repeated ANOVA. The results were as follows. First, the use of the lower extremity supporter affects the ground reaction force along the anterior-posterior axis(Y). Second, the vertical(Z-axis) reaction force on the upper part of the lower extremity supporter increase because of the difference between the interval of vertical movement. Third, the muscle activity of the lateral gastrocnemius and rectus femoris was higher in the upper part of the lower extremity supporter. Further research for example, on a comparative analysis of joint moments, the effects of direct stressor on joints. and the relationship between muscle activity and joint movement, is necessary for a better understanding of the effects of the lower-extremity supporter.
The Effect of Form and Hardness of Outsoles on the Motion of the Lower Extremity Joints and on Foot Pressure during Gait
Kim, Eui-Hwan ; Kim, Sung-Sup ; Kwon, Moon-Seok ; Wi, Ung-Ryang ; Lim, Jung ; Chung, Chae-Wook ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 223~230
DOI : 10.5103/KJSB.2011.21.2.223
The purpose of this study was to analysis the effect of form and hardness of outsoles on the motion of the lower extremity joints and on foot pressure during gait. The subjects were 15 women(mean age,
years), who had no serious musculoskeletal, coordination, balance or joint/ligament problems within 1 year prior to the study. The pelvic tilt, joint angles at the lower extremities and the vertical ground reaction force(GRF) were compared during gait with 3 types of shoes (A, B, C) by using one-way repeated ANOVA(p<.05). During gait, the peak tilt angle and the range of motion(ROM) of the ankle and knee joints were found to be significantly different among the 3 types of shoes. The type C shoes showed a significantly lower mean second maximum vertical GRF than types A and B. The curved outsoles of type C shoes, which had a form and hardness different from those of A and B, was designed strategically for walking shoes to provide stability to the Additionally, type C induced the dispersion of eccentric pressure and made the center of pressure roll over to the center line of the foot.
Comparative Analysis of Foot Pressure Distribution by Functional Insole to be Transformed and Restored During Walking
Park, Seung-Bum ; Lee, Kyung-Deuk ; Kim, Dae-Woong ; Yoo, Jung-Hyeon ; Kim, Kyung-Hun ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 231~241
DOI : 10.5103/KJSB.2011.21.2.231
The purpose of this study was to analyze the distribution of foot pressure generated by active materials of a functional insole. Comfort is an important consideration while selectingfootwear and insoles. Consequently, it has an influence on injury. The development of new materials for functional insoles is considered one of the more important points for their manufacture. The method adopted in this study is as follows. First, ten healthy males were selected as subjects for the study. Each subject's foof was pre-screened podoscope(Alfoots, Korea) to check for the presence of any foot abnormalities, Two kinds of equipment were used for the study: a foot pressure device from Pedar-X, Germany, and a treadmill from Pulsefitness, UK. Next, each subject was asked to test four types of insoles(insoles of outdoor shoes, indoor shoes, walking shoes, and sports shoes) via walking trials on the treadmill at a constant speed of 4.2 km/h. The pressure distribution data(contact area, maximum force, maximum peak pressure, and maximum mean pressure) was collected using the pressure device at a sampling rate of 100 Hz. Results of the tests showed that all four types of functional insoles increased contact areas whit the foot. Further, functional insoles of walking shoes and sport shoes decreased the foot pressure. From these results, we conclude that the active materials of functional insoles of shoes can increase the contact area and provide greater comfort.
Effect of Trunk Flexion on Muscle Activity, Motion of Scapular and Scapulohumeral Rhythm
Park, Seung-Kyu ; Han, Song-E ; Kang, Jeong-Il ; Lee, Joon-Hee ; Yang, Dae-Jung ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 243~252
DOI : 10.5103/KJSB.2011.21.2.243
The purpose of this study was to determine the effect of trunk posture on muscle activity and motion of scapular and scapulohumeral rhythm. Thirty-one healthy subjects performed right-arm abduction and adduction along the frontal plane while standing in both upright and flexed posture of trunk. Scapular upward rotation, anterior tilting and internal rotation ware recorded using a motion analysis system and muscle activity of upper trapezius, lower trapezius and serratus anterior ware recorded using surface electromyography during abduction and adduction in both trunk postures. then, scapulohumeral rhythm was calculated. Scapulohumeral rhythm and scapular posterior tilting in flexed posture was significantly decreased than in upright posture. Also, muscle activity of lower trapezius in flexed posture was significantly increased and serratus anterior was significantly decreased than in general posture. The result of this study revealed that flexed posture of trunk altered the muscle activity and kinematic of scapular. Measurement of trunk posture should be included the evaluation of dysfunction and disorder of shoulder girdle since rehabilitation of trunk posture is important to restore of upper limbs function.
Prediction of Energy Expenditure by Using a Tri-axial Accelerometer
Lee, Hee-Young ; Kim, Seung-Hyeon ; Lee, Dong-Yeop ; Park, Sun-Woo ; Kim, Young-Ho ;
Korean Journal of Sport Biomechanics, volume 21, issue 2, 2011, Pages 253~258
DOI : 10.5103/KJSB.2011.21.2.253
The purpose of this study was to compare metabolic energy expenditure with the computed kinetic energy for different speeds of walking and running over the treadmill and to find the relevance for individual and group equation by performing a statistical analysis, Bland-Altman plot. Seven male subjects participated, and they were required to walk and run on the treadmill with the gas analyzer and triaxial accelerometer. Walking speeds were 3.0, 4.0, 5.0 and 6.0 km/h and running speeds were 7.0, 8.0 and 9.0 km/h respectively. Kinetic energy was calculated by the integration of acceleration data and compared with the metabolic energy measured by a gas analyzer. Correlation coefficients showed relatively good between the measured metabolic energy and the calculated kinetic energy. In addition, a dramatic increase in kinetic energy was also observed at the transition speed of walking and running, and two standard deviations in Bland-Altman plot, derived from the difference between measured and predicted values, were 1.14, 2.53, 2.93, 1.80, 2.80, 0.60 and 2.48 respectively. It was showed that there is no difference for methods of how to predict the kinetic energy expenditure for individual and group even though people had each different physical characteristic.