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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 24, Issue 4 - Dec 2014
Volume 24, Issue 3 - Sep 2014
Volume 24, Issue 2 - Jun 2014
Volume 24, Issue 1 - Mar 2014
Selecting the target year
The Effect of Stretch-Shortening Cycle on the Joint Power of the Jireugi in the Taekwondo Juchumseogi Stance
Choi, Chi-Sun ; Chung, Chul-Soo ; Shin, In-Sik ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 1~9
DOI : 10.5103/KJSB.2014.24.1.001
The purpose of this study was to investigate the muscle mechanical properties of the pelvic axial pre-rotational movement for the Jireugi in the Taekwondo Juchumseogi stance. Eleven elite Taekwondo Poomsae athletes participated. Each participant performed 5 right hand Jireugi in Juchumseogi stance as fast and strong as possible while their motion was recorded by a 3D motion analysis system and the ground reaction forces by two force plates. The power and work of the muscular group surrounding the waist were analyzed to verify the effect of the stretch-shortening cycle (SSC) theory. The cause of the greater power seems to be the application of the SSC by the muscles surrounding the waist during the preparation phase of the pre-rotation group. For the none pre-rotation group, they only used the concentric contraction of the muscles surrounding the waist. Because the pre-rotation group used the SSC theory, they had the effect of shortening of the range of movement, creating a fast and more powerful rotation, thus anticipating the increase the magnitude of impact.
Kinematic and Electromyographic Analysis of Backhand Clear Motion according to the Type of Hitting in Badminton
Kim, Ho-Mook ; Woo, Sang-Yeon ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 11~18
DOI : 10.5103/KJSB.2014.24.1.011
The purposes of this study were to analyze the kinematics and electromyographic variables of the upper extremity for the backhand clear motion according to the type of hitting in badminton. Seven elite male university players were selected as the subjects. Four digital video cameras and Noraxon Telemyo 2400 were used to collect the 3D kinematics and electromyographic data. The results were as follows: 1) in the phase of impact, the time of motion for the overhead backhand clear was the longest, 2) in the event of impact, the distance of step toward X direction was the longest and the distance of step toward Y direction was the shortest for the overhead backhand clear, 3) in the event of backswing, the rotation angles of shoulder and pelvis and the flexion angle of shoulder for the overhead backhand clear were the biggest, 4) the maximum flexion angular velocity of shoulder and the maximum extension angular velocity of elbow for the overhead backhand clear were the biggest, and 5) in the phase of impact, mean EMG of the wrist flexor, triceps, and trapezius muscle for the overhead backhand clear was bigger than that for the underhand stroke and in the phase of follow-through, mean EMG of the wrist flexor and extensor, biceps, triceps, and trapezius muscle for the overhead backhand clear was the biggest.
Comparisons of Foot Pressure Patterns between Experienced Skiers and Intermediate Skiers during Alpine Skiing
Kim, Joo-Nyeon ; Yoo, Si-Hyun ; Ha, Sung-He ; Kim, Jin-Hae ; Ryu, Ji-Seon ; Park, Sang-Kyoon ; Yoon, Suk-Hoon ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 19~26
DOI : 10.5103/KJSB.2014.24.1.019
This study investigated foot pressure patterns between experienced skiers and intermediate skiers during alpine skiing. Five experienced skiers and five intermediate skiers participated in this study. Foot pressure measurement system was used to measure vertical ground reaction force (vGRF) and contact area under the six plantar regions. Each participant was asked to perform basic parallel turns and carved turns on a
groomed slope. Each right turn was divided into the initiation phase, the steering phase 1 and 2. For the initiation phase of the basic parallel turns, significantly greater contact area was found on the LRF and RRF of the intermediate skiers (p<.05) and significantly greater vGRF was found on the LRF of the intermediate skiers (p<.05). Also significantly greater vGRF and contact area were found on the LRF and RRF of the intermediate skiers at the steering phase 1 (p<.05) and on the LRF of the intermediate skiers at the steering phase 2 (p<.05). For the carved turns, significantly greater vGRF and contact area were found on the LRF and RRF of the intermediate skiers at all three phase (p<.05). On the other hand, significantly greater vGRF was found on the RFF of the experienced skiers at the steering phase 1 (p<.05). Also significantly greater vGRF and contact area were found on the RMF of the experienced skiers at the steering phase 2 (p<.05). In order to increase performance, we suggest that the intermediate skiers should be unweighted at the initiation phase and shift the body weight to the forefoot of the outer foot at the steering phase 1. Also, the outer ski should be loaded more than the both skis at the steering phase 1 and 2.
Effects of Knee Brace on the Anterior Cruciate Ligament Injury Risk Factors during Spike Take Off in Female Volleyball Players
Yang, Chang-Soo ; Lim, Bee-Oh ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 27~33
DOI : 10.5103/KJSB.2014.24.1.027
In volleyball, the most common injuries are anterior cruciate ligament (ACL) tears. For this reason, volleyball players frequently use knee brace as prophylactic and rehabilitation measures. The purpose of the study was to investigate the effects of knee brace on anterior cruciate ligament injuries risk factors during spike take off in female volleyball players. Fifteen female volleyball players were recruited and performed randomly spike take off with and without knee brace. Kinematics and ground reaction data were collected to estimate the anterior cruciate ligament injuries risk factors. The ACL risk factors are knee maximum flexion angle, thigh maximum adduction angle, thigh maximum internal rotation angle, shank maximum abduction angle, shank maximum external rotation angle, knee maximum extension moment and knee maximum abduction moment. Data were analyzed with paired samples t-test with Bonfferoni collection. Female volleyball players with knee brace had no significant results in knee maximum flexion angle, thigh maximum adduction angle, thigh maximum internal rotation angle, shank maximum abduction angle and shank maximum external rotation angle compare to without knee brace. Female volleyball players, however, with knee brace showed more reduced knee maximum extension moment and knee maximal abduction moment than without knee brace. In conclusion, Female volleyball players with knee brace reduced anterior cruciate ligament stress.
Relationship between Muscle Strength and Tendon Stiffness of the Ankle Plantarflexors and Its functional Consequence
Han, Seong-Won ; Lee, Dae-Yeon ; Lee, Hae-Dong ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 35~42
DOI : 10.5103/KJSB.2014.24.1.035
Tendon elasticity is an important factor affecting muscle function and thus human movements. It has been reported that the mechanical properties of tendon are adaptable to external loading condition. Based on the adaptability of muscle and tendon to external loading conditions, one can assume that there might be an optimum ratio between muscle strength and tendon stiffness. The present study aimed to investigate whether there is correlation between plantar flexor muscle strength and stiffness of the achilles tendon (AT). Twenty two male subjects (age:
) performed maximum voluntary isometric plantarflexion on a custom-built dynamometer and muscle-tendon junction of the medial gastrocnemius muscle was simultaneously monitored using a real-time ultrasound imaging machine. The averages of muscle force and tendon stiffness were
, respectively. Significant positive correlation was observed between muscle strength and tendon stiffness (r=0.8507), indicating that the muscle force is proportional to tendon stiffness. The results might have been used in computational modeling and criterion of training progress level in the fields of training and rehabilitation.
Analysis of the Ground Reaction Force Parameters According to the Change of Position and Weights of Bag during Downward Stairs Between Dominant and Non-dominant in Upper & lower limbs
Hyun, Seung-Hyun ; Lee, Ae-Ri ; Ryew, Che-Cheong ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 43~50
DOI : 10.5103/KJSB.2014.24.1.043
The purpose of this study was to analyze of the GRF (ground reaction force) parameters according to the change of positions and weights of bag during downward stairs between dominant and non-dominant in upper & lower limbs. To perform this study, participants were selected 9 healthy women (age:
, body mass:
), divided into 2 carrying bag positions (dominant arm/R, non-dominant arm/L) and walked with 3 type of bag weights (0, 3, 5 kg) respectively. One force-plate was used to collect GRF (AMTI OR6-7) data at a sample rate of 1000 Hz. The variables analyzed were consisted of the medial-lateral GRF (Fx), anterior-posterior GRF (Fy), vertical GRF (Fz), impact loading rate and center of pressure (COPx, COPy, COP area, COPy posterior peak time) during downward stairs. 1) The Fx, Fy, Fz, COPx, and COP area of GRF were not statistically significant between dominant leg and non-dominant leg, but non-dominant leg, that is, showed the higher COPy, and showed higher impact loading rate than that dominant leg during downward stairs. 2) In bag wearing to non-dominant arm, Fx, Fz, COPx, COPy, impact loading rate and COP area showed increase tendency according to increase of bag weights. Also, against bag wearing to dominant arm, non-dominant showed different mechanism according to increase of bag weights. The Ground Reaction Force parameters showed different characteristics according to the positions and weights of bag during downward stairs between dominant and non-dominant arm.
Analysis of Kinetic Differences According to Ankle Taping Types in Drop Landing
Lee, Kyung-Ill ; Hong, Wan-Ki ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 51~57
DOI : 10.5103/KJSB.2014.24.1.051
The purpose of this study was to compare and analyze kinetic variables of lower limbs according to types of ankle taping in drop landing. For this, targeting seven male basketball players (average age:
, average height:
, average weight:
) with no instability of ankle joints, the drop landing motion was conducted according to three types of inelastic taping (C-type), elastic taping (K-type), and no treatment (N-taping). Based on the result, the next conclusion was reached. First, the effect of taping for the players with stable ankles was minimal and the high load on ankle joints offset the fixing effect of inelastic taping. Thus the inelastic taping for the players with stable ankles did not have an effect on the control of dorsal flexion during one-foot landing. Second, increasing angular velocity by increasing the movable range of knee joints disperses impact forces, yet inelastic taping restricted the range of knee joint motion and at the same time increased angular velocity, adding to a negative effect on knee joints. Third, inelastic taping induced inefficient motion of Lower limbs and unstable impact force control of ankle joints at the moment of landing and produced maximum vertical ground reaction force, which led to an increase of load. Therefore, inelastic ankle taping of players whose jump actions occur very often should be reconsidered. Also, it is thought that this study has a great meaning in proving the problem of inelastic taping related to knee pain with unknown causes.
Effects of Knee Joint Muscle Fatigue and Overweight on Shock Absorption during Single-Leg Landing of Adult Women
Kim, Tae-Hyeon ; Youm, Chang-Hong ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 59~66
DOI : 10.5103/KJSB.2014.24.1.059
The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on shock absorption during single-leg landing of adult women. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. Both the normal weight group and the overweight group showed that use soft landing and ankle dominant strategy. The peak vertical ground reaction force, the knee joint absorption power, and eccentric work done, as the increase of knee joint muscle fatigue level, showed a decrease. And the hip joint absorption power and eccentric work done, as the increase of weight, was less than the overweight group showed the normal weight group. In conclusion, the accumulation of the knee joint muscle fatigue and the increase of body weight may lead to an increased risk of injury during landing.
The Kinematic Analysis of the Lower Extremity Joint According to the Changes in Height of Box during Step Aerobics
Kim, Kyu-Soo ; So, Jae-Moo ; Kim, Yun-Ji ; Yeo, Houng-Chul ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 67~74
DOI : 10.5103/KJSB.2014.24.1.067
This study researched into the left-right inclination of the rear foot at the lower limb joints, knee joint angle, angular velocity of the knee joint, angular acceleration and the max. Based on the analysis of kinematics according to the changes in the height of step box (6, 8, 10 inches) during step aerobics of female college students majoring in physical education. The findings of this study are as follows: Then angle of the knee joint decreased as the height of the step box increased the min. Angle was measured right before the right foot was on the step box, and the angle tended to decrease as the step box get heightened. The left-right inclination of the rearfoot angle according to the height of step box increased as the height increased. In the 'pull-up' stage during which the weight was loaded on the right foot the angle increased, while in the right foot stepping stage during which the right foot was on the ground, the left-right inclination of the rearfoot angle increased as the height of the step box increased. The angular velocity of the knee joint according to the height of step box started increasing when the right foot initially stepped on the step box and during the initial stepping section, the angular velocity decreased as the height of step box increased. The changes in angular acceleration of the knee joint according to the height of step box increased as the height of step box increased.
Effects of the Upright Body Type Exercise Program on Postures and Foot Balance in Female High School Students
Son, Nam-Young ; Lee, Joong-Sook ; Kim, Joo-Hyeok ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 75~83
DOI : 10.5103/KJSB.2014.24.1.075
The purpose of this study was to investigate the degree of improvement of posture and foot balance between the exercise group and the control group after upright body type exercise program of 12 weeks with 14 female students in B female high school. According to the procedure of this study, following conclusion came out. First, The change of head's posture became near a centerline and a significant decrease from
in experimental group and there was a statistically significant difference (p<.002). The change of left foot balance was near the perfect balance (50%) from
and right foot balance was from
in experimental group and there were near the perfect balance (50%). The change of left foot balance of control group fall away the perfect balance (50%) from
, right foot balance also fall away the perfect balance (50%) from
. As a conclusion, upright body type exercise program considered to effect posture and foot balance in female high school girls. Consequently It was suggested that upright body type exercise program with improvement and prevention for posture's unbalance of female high school girls. This program could be utilized for improvement of youth posture and foot balance.
Correlation between Balance Ability, Muscle Strength, and Muscle Endurance, in Taekwondo, Soccer, and Gymnastics Athletes
Park, Seok-Woo ; Ryu, Young ; Kim, Kew-Wan ;
Korean Journal of Sport Biomechanics, volume 24, issue 1, 2014, Pages 85~93
DOI : 10.5103/KJSB.2014.24.1.085
The purpose of this study was to investigate a relationship among Taekwondo, soccer and gymnastic athletes their balance ability and lower extremity muscle strength, muscle endurance and also whether these variables show differences by sports type. For this purpose, 10 Taekwondo athletes, 10 soccer athletes and 10 gymnastic athletes that is a high school in I area were selected and their balance ability, isokinetic muscle strength and muscle endurance were measured by using force platform (AMTI) and isokinetic measurement (HUMAC NORM). Then the following results were obtained by conducting pearson product-moment correlation analysis and one-way ANOVA. In case of both right and left foot one-leg standing with open-eyes, there was a relation between both knee extension maximal muscle strength of Taekwondo, soccer, gymnastic athletes and balance ability, and in case of right foot one-leg standing with open-eyes, there was a relation between that is right plantar flexion and dorsi flexion maximum muscle strength and muscle endurance of Taekwondo, soccer, gymnastic athletes and their balance ability. Furthermore, in case of left dorsi flexion maximum muscle strength, there were significant differences in order of Taekwondo, gymnastics and soccer, and for isokinetic plantar flexion maximum muscle endurance, both right and left showed significant differences in order of Taekwondo, gymnastic and soccer.