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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 22, Issue 4 - Dec 2012
Volume 22, Issue 3 - Sep 2012
Volume 22, Issue 2 - Jun 2012
Volume 22, Issue 1 - Mar 2012
Selecting the target year
Qualitative Analysis of Pressure Intensity and Center of Pressure Trajectory According to Shoe Type
Yi, Kyung-Ock ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 261~268
DOI : 10.5103/KJSB.2012.22.3.261
The purpose of this study was to qualitatively analyze pressure intensity and the center of pressure(COP) trajectory according to shoe type. Subjects were ten first-year female university students. The EMED-AT 25/D(Novel, Germany) was used to measure pressure intensity and COP trajectory. The COP Excursion Index(CPEI) was used for within subject test design. Independent variables were bare feet and six types of shoes. Dependent variables were center of pressure trajectory and pressure intensity. Barefeet and five toed shoes had a similar pressure intensity and COP trajectory. COP trajectory for all other shoe types showed a medial wobble at the heel. Pressure intensity for all other shoe types was related to the structure of the shoes. In conclusion, different shoe types can not only affect gait, but they can also influence foot deformities, pain, and dysfunction.
Kinematic Analysis According to the Intentional Curve Ball at Golf Driver Swing
Hong, Soo-Young ; So, Jae-Moo ; Kim, Yong-Seok ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 269~276
DOI : 10.5103/KJSB.2012.22.3.269
The purpose of This study`s aim is to examine the difference in the changes of body segment movement, variables for ball quality, and carry at golf driver swing according to the ball quality using comparative analysis. Regarding the impact variables according to the ball quality using the track man and carry, club speed was the fastest at draw shot, ball speed was the fastest at straight shot, and smash factor was the lowest at draw shot. About the vertical launch angle, the fade shot showed the highest launch angle while the max height of the ground and ball was the highest at fade shot. And carry was the longest at draw shot. For the flight time, it was the longest at draw shot. The landing angle was the largest at fade shot. About the club head position change and trajectory, at the overall event point, the fade shot drew a more outer trajectory at the point of the follow through(E6) than the straight or draw shot. Regarding the angular speed of shoulder rotation, at the overall event point, the fade shot showed the greatest angular speed change in the follow through(E6). Also, about the angular speed of pelvic rotation, at the overall event point, the draw shot showed the greatest angular speed change at the point of down swing(E4). Concerning the stance angle change, both straight and fade shots were open as the concept of open stance whereas the draw shot was close as that of close stance. Regarding the previous study, the most important factor of deciding Ball Quality is the club face angle`s open and close state at Impact. In short, the Ball Quality and carry were decided by this factor.
The Analysis on the Changes in Beginners Batting Movements through Undergraduate Baseball Lectures
Chun, Young-Jin ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 277~284
DOI : 10.5103/KJSB.2012.22.3.277
The purpose of this study was to find out the changes in beginners` batting movements after taking undergraduate baseball lectures, by comparing and analyzing the speed of bat, the angle of body and its segments, the angular velocity and so on. For this purpose, the author picked up five undergraduates who had not taken baseball lectures, and conducted three-dimension computerized tomography twice on them, that is, before and after taking baseball classes, with eight infrared cameras and two force platforms. The conclusions are, first, the time required for swing was shortened after taking the classes. Second, the maximum velocity of the bat-end was increased. Third, at the time of impact, while the rotation angles of the pelvis and the tip of left foot were increased, the left elbow had more flexion after the classes. Fourth, the size of ground reaction force was increased at the point of swing where the ground reaction force of left foot became maximized. As we can infer from these conclusions, beginners` hitting movements before taking baseball classes tended to swing only with the arms, without waist rotation and weight shift of the lower body, but after the classes, their movements were proved to be corrected into the swing using the lower body. For the future studies, the author expects a research in a close to real environment by using pitching machine.
Comparison between the Balance of Skilled and Less-Skilled Players during Successful and Failed Front Kick and Turning Side Kick Motions
Yoo, Si-Hyun ; Ryu, Ji-Seon ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 285~293
DOI : 10.5103/KJSB.2012.22.3.285
The aim of this study is to identify the appropriate movement for maintaining postural balance during Front Kick and Turning Side Kick motions. To do so, ten Taekwondo athletes: five skilled players(S, body mass:
) and five less-skilled players(LS, body mass:
) participated in this study. A three-dimensional motion analysis was performed on the participants using eight infrared cameras and two force plate(sampling frequency of 200 Hz and 2000 Hz for S and LS players, respectively). The participants` motions were divided into: a front-kick phase(P1) and a turning-side-kick phase(P2). For P2(p<.05), the range and root mean square(RMS) of the ground reaction torque and the M-L mean velocity of COP were greater for LS than for S; similarly, for P2(p<.05), the M-L range, A-P range, and velocity of the COP were greater for LS than for S. Further, the M-L range and maximum velocity of the COP was greater for failure than for success(p<.05). The femoral biceps muscle for bending the knee joint was significantly stronger in S than in LS(p<.05). It is expected that these results will be useful in developing a training program for improving the balance and stability of Taekwondo poomsae athletes and improve their front-kick and turning-side-kick motions.
Biomechanical Analysis of Injury Factors in the Run UP and Jump Phases of the Jetѐ
Lee, Jin ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 295~304
DOI : 10.5103/KJSB.2012.22.3.295
This study, through biomechanical analysis, conducts a risk assessment of injury occurrence in ballet dancers while they perform running and jumping movements. The participants were nine female collegiate students majoring in ballet(age:
). Descriptive data were expressed as
deviation(SD) for all variables. An independent t-test was conducted to determine how the following variables differed: duration time, position of the center of gravity, angle of the hip, torque of the hip, and muscle activity. All comparisons were made at the p<0.05 significance level. The results show that the jump time was two times longer than the run time in the duration time. The jump length was also longer than the run. The angle of the hip and the torque at the hip were higher in the right. The vastus medialis muscle was most frequently used. These findings demonstrate that participants` jumps may require more biomechanical variables for performance of better and more correct
Effect of Joint Kinetics and Coordination on the Within-Individual Differences in Maximum Vertical Jump
Kim, Yong-Woon ; Seo, Jung-Suk ; Han, Dong-Wook ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 305~314
DOI : 10.5103/KJSB.2012.22.3.305
The purpose of this study was to investigate the effects of joint kinetics and coordination on within-individual differences in maximum vertical jump. 10 male subjects aged 20 to 30 performed six trials in maximum vertical jump and with based on jump height the good(GP) and bad(BP) performances for each subject were compared on joint kinetics of lower extremity and coordination parameters such as joint reverse and relative phase. The results showed that maximum moment, power, and work done of hip joint and maximum moment of ankle joint in GP were significantly higher than that in the BP but no significant differences for the knee joint. We could observe a significant difference in joint reverse timing between both conditions. And also the relative phase on ankle-knee and ankle-hip in GP were significantly lower than that in the BP, which means that in GP joint movements were more in-phase synchronized mode. In conclusion, mechanical outputs of hip and ankle joints had an effect on within-individual differences in vertical jump and the inter-joint coordination and coordination including sequence and timing of joint motion also might be high influential factors on the performances within individual.
The Study of Strategy for Energy Dissipation During Drop Landing from Different Heights
Cho, Joon-Haeng ; Koh, Young-Chul ; Lee, Dae-Yeon ; Kim, Kyoung-Hun ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 315~324
DOI : 10.5103/KJSB.2012.22.3.315
The purpose of current study was to investigate the effects of the heights on the lower extremities, torso and neck segments for energy dissipation during single-leg drop landing from different heights. Twenty eight young healthy male subjects(age:
) were participated in this study. The subjects performed the single-leg drop landing from the various height(30, 45 & 60 cm). Force plates and motion-capture system were used to capture ground reaction force and kinematics data, respectively. The results were as follows. First, the ROM at the ankle, knee, hip and trunk was increased with the increased heights but the ROM at the neck was increased in the 60cm. Second, the angular velocity, moment and eccentric work at the ankle, knee, hip, trunk, and neck was increased with the increased heights. Third, the contribution to total work at the knee joint was not significantly different, while the ankle joint rate was decreased and hip and neck rate was increased in the 60cm, and trunk rate was increased with the increased heights. Lastly, the increase in landing height was able to augment the level of energy dissipation not only at the lower extremities but also at the trunk and neck. The findings showed that drop landing affect trunk and neck with lower extremity joints. Therefore, we need to consider that trunk and neck strengthening including stability should be added to reduce sports injury during prevention training.
Effect of Added Mass between Male and Female on The Lower Extremity Joints Angular Velocity, Moment, Absorb Energy During Drop Landing
Kwon, Moon-Seok ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 325~332
DOI : 10.5103/KJSB.2012.22.3.325
This study aimed to analyze the effects of external load between male and female on angular velocity, moment, and absorbed energy of the lower-extremity joints during drop landing. The study subjects were 9 male($mass
Analysis of Lower Extremity Muscle Activities in Parkinson`s Patients for Improving to Stop Task
Yang, Chang-Soo ; Lim, Bee-Oh ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 333~339
DOI : 10.5103/KJSB.2012.22.3.333
Freezing of gait is a severely problem in people with Parkinson`s disease. The purpose of this study was to investigate the muscle activities of adductor longus, gluteus medius, gluteus maximus, biceps femoris, rectus femoris, gastrocnemius, and tibialis anterior using Noraxon 8 channels EMG system during stop task in patients with Parkinson`s disease. Seven parkinson`s patients and age matched normal participants were recruited in the study. Filtered EMG signals were rectified, smoothed and integrated. To control for the altered timing and magnitude of activity, iEMG was normalized for time and peak value. The results indicated that the patients with Parkinson showed decreased gait cycle, stance phase, swing phase time, swing phase time ratio and increased stance phase time ratio than normal participants. The patients with Parkinson showed decreased gastrocnemius muscle activity time ratio, while increased tibialis anterior muscle activity time ratio than normal participants. During stance phase before stop, the patients with Parkinson showed relatively lower average and peak iEMG in anterior tibialis and gastrocnemius muscle than normal participants. During swing phase before stop, the patients with Parkinson showed relatively higher average iEMG in gastrocnemius muscle than normal participants. During stop phase, the patients with Parkinson showed relatively lower average and peak iEMG in anterior tibialis and gastrocnemius muscle than normal participants.
Comparison of Muscle Activities of Thoracic and Lumbar Extensors during Trunk Lift Exercises According to Exercise Position
Koh, Eun-Kyung ; Jung, Do-Young ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 341~348
DOI : 10.5103/KJSB.2012.22.341
The purpose of this study was to compare the muscle activities of the thoracic extensor(TE) and lumbar extensor(LE) during trunk lift (TL) exercise according to exercise position. Seventeen healthy subjects with no medial history of back pain were recruited for this study. Subjects performed the TL exercise in prone, quadruped and heel-sitting positions. The activities of the TE and LE were measured using surface electromyography during TL exercise in each exercise position. A one-way repeated-measures analysis of variance (ANOVA) was used to compare the normalized muscle activities of the TE and LE and the TE/LE ratio. The results showed that there was not significant effect of exercise position on the muscle activities of TE(p>.05). However, there was significant effect of exercise position on the muscle activities of LE and the TE/LE ratio(p>.05). Post hoc pair-wise comparisons with Bonferroni correction showed that both muscle activities of LE and TE/LE ratio in prone position were significantly different in those in heel-sitting and quadruped positions, during TL exercise, respectively. The TE/LE ratio was the greatest for TL exercise in heel-sitting position. Therefore, for selective activation of the TE muscle, we recommend performing the TL exercise in heel-sitting or quadruped position.
The Effect of Progressive Lumbar Stability Exercise on the Transversus Abdominis Muscle Thickness and Lower extremity muscle Fatigue Index in Soccer Players
Lee, Joon-Hee ; Park, Seung-Kyu ; Kang, Jeong-Il ; Yang, Dae-Jung ; Kim, Je-Ho ; Jeong, Yong-Sik ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 349~356
DOI : 10.5103/KJSB.2012.22.3.349
This study aimed to assess the effects of progressive lumbar stability exercises and lumbar stability exercises on changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index in soccer players. Ten subjects were assigned to undergo training in each of the 2 groups, namely, the progressive lumbar stability exercise group and lumbar stability exercise group. Each intervention session lasted for 30 min, and 4 sessions were conducted in a week for 6 weeks for soccer players of S. University in Jeonnam, Korea. Changes in the transversus abdominis muscle thickness and lower extremity muscle fatigue index were measured using ultrasound and surface electromyogram. The results of the ultrasound measurement for the transversus abdominis muscle thickness indicated that progressive lumbar stability exercises were more effective than lumbar stability exercises. The results of the lower extremity muscle fatigue index measurements using surface electromyogram indicated that the fatigue index decreased in the progressive lumbar stability exercise group. Progressive lumbar stability exercise is believed to have put more workload during the shaking of the limbs, leading to increased stability and increased efficiency of the lower extremity muscle, thereby decreasing the fatigue index. Therefore, progressive lumbar stability exercises can be an effective measure for preventing injuries and improving the game performance of sports players by increasing the transversus abdominis muscle thickness and decreasing the lower extremity muscle fatigue index.
Relationship between Lower -Limb Joint Angle and Muscle Activity due to Saddle Height during Cycle Pedaling
Seo, Jeong-Woo ; Choi, Jin-Seung ; Kang, Dong-Won ; Bae, Jae-Hyuk ; Tack, Gye-Rae ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 357~363
DOI : 10.5103/KJSB.2012.22.3.357
The purpose of this study was to investigate the effects of different saddle heights on lower-limb joint angle and muscle activity. Six elite cyclists(age:
, cycle career:
) participated in three min. submaximal(90 rpm) pedaling tests with the same load and cadence based on saddle heights where subject`s saddle height was determined by his knee flexion angle when the pedal crank was at the 6 o`clock position. Joint angles(hip, knee, ankle joints) and the activity of lower limb muscles(biceps femoris(BF), vastus lateralis(VL), tibialis anterior(TA) and gastrocnemius medial(GM)) were compared by measuring 3D motion and electromyography(EMG) data. Results showed that there were significant differences in minimum hip & knee joint angle and range of motion of hip and knee joint between saddle heights. Onset timing and integrated EMG of only BF among 4 muscles were significantly different between saddle heights. Especially there was a negative relationship between minimum hip joint angle and onset timing of BF in most subject, which means that onset timing of BF became fast as the degree of bending of the hip joint became larger by saddle height. Optimal pedaling will be possible through increased amount of muscle activation due to the appropriate burst onset timing by proper pedaling posture with adjusted saddle height.
Development of Wearing of Musculo-Skeletal Functional Garment for Adolescents` Idiopathic Scoliosis -With the Principle of Sports Taping Applied-
Park, Yang-Sun ; Woo, Byung-Hoon ; Kim, Jong-Moon ; Lim, Young-Tae ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 365~371
DOI : 10.5103/KJSB.2012.22.3.365
We aimed to analyze the muscle activity of adolescent patients with idiopathic scoliosis during gait and develop the wearing of musculo-skeletal functional garment by applying the principle of sports taping based on the result of the analysis. We selected 20 male students between the ages of 13 and 18 and divided them into 2 groups: one group consisted of 10 patients with idiopathic scoliosis <20 degrees of Cobb`s Angle: the other group had 10 normal students. Using, we measured and analyzed the muscle activity of 8 different regions: left and right latissimus dorsi, left and right thoracolumbar fascia, left and right gluteus medius, and left and right biceps femoris during gait. Our results can be summarized as follows: Firstly, in patients with idiopathic scoliosis, the gait showed a significantly low activity of the right latissimus dorsi muscle when the left foot was supported on the ground(p<.05). Secondly, in the overall gait cycle, the patients showed a higher activity of the right thoracolumbar fascia and right gluteus medius than that seen in the normal students: however, this difference was not statistically significant. Thirdly, by applying sports taping on the bisis of the results, this study developed the wearing of musculo-skeletal functional garment that could maximize the stimuli of the right latissimus dorsi and alleviate muscle contraction of the right thoracolumbar fascia and right gluteus medius, while expanding the spinal line upward and downward, by focusing on the difference between left and right muscular strength of the muscle activity of the bright latissimus dorsi. Overall, we expect that by wearing of musculo-skeletal functional garment, the muscular functions in adolescents with idiopathic scoliosis.
Technical Note : Development of Electric Riding Machine for Cycle Fitting
Bae, Jae-Hyuk ; Choi, Jin-Seung ; Kang, Dong-Won ; Seo, Jeong-Woo ; Tack, Gye-Rae ;
Korean Journal of Sport Biomechanics, volume 22, issue 3, 2012, Pages 373~378
DOI : 10.5103/KJSB.2012.22.3.373
The purpose of this study was to develop an electric riding machine for cycle fitting to control riding posture easily, to measure frame size quantitatively, and to overcome disadvantages of the traditional systems. The electric riding machine consisted of actuator, load controller, and display & control unit. The actuator unit by BLDC(BrushLess Direct Current) motor drives the saddle height up and down, the crank forward and backward, the handlebar up and down, and the handlebar forward and backward. The load controller unit controls loads by Eddy current controller with electromagnet and aluminum circular plate. The display & control unit consisted of frame size controller and display panel which shows top tube length(485~663mm), head tube length(85~243mm), seat tube length(481~671mm), and seat tube angle(
). The range of frame size control for developed electric riding machine did not have difference compared to traditional commercial systems, but quantitative and precise control with 0.1 mm length and
angle was possible through digital measurement. Unlike traditional commercial systems, frame size control was possible during riding through motor driven method, thus fitting duration decreased. It is necessary for further improvement to have feedback from users. It is believed that developed electric riding machine can help to develop domestic fitting system.