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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 19, Issue 4 - Dec 2009
Volume 19, Issue 3 - Sep 2009
Volume 19, Issue 2 - Jun 2009
Volume 19, Issue 1 - Mar 2009
Selecting the target year
Comparison of The Hamstring-to-Quadriceps Strength Ratios of Collegiate Soccer Players and Age-Matched Healthy Students
Seo, Byoung-Do ; Shin, Hyung-Soo ; Han, Dong-Wook ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 617~625
DOI : 10.5103/KJSB.2009.19.4.617
The primary purpose of this study was to compare the hamstring-to-quadriceps strength(H/Q) ratios in collegiate soccer players and normal age-matched healthy students, and the secondary purpose was to investigate the changes in the H/Q ratio according to the degree of knee flexion. Twenty-five subjects volunteered to participate in this study. The study group comprised 12 healthy male collegiate soccer players, and the control group, 13 healthy age-matched male collegiate students. The modified N-K table was used for isometric strength measurement(unit: N). Mann-Whitney tests were performed to determine the differences in the H/Q ratios of soccer players and age-matched students at different knee flexion angles of the dominant leg. The strength of the hamstring muscle in the study group was significantly lower than that observed in the control group at knee flexion angles of
(p<05). The strength of the quadriceps muscle in the study group was significantly higher than that observed in the control group at flexion angles of
(p<.05). The H/Q ratios in the study and control groups differed significantly at all angles (
, p<.001 and
The Effects of Breathing Control on Kinetic Parameters of Lower Limbs during Walking Motion in Korean Dance
Park, Yang-Sun ; Jang, Ji-Young ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 627~636
DOI : 10.5103/KJSB.2009.19.4.627
This study aims to provide a scientific basis for the abstract beauty of dance by analyzing the effects of controlling the breath during the walking motion of Korean dance. The objective of the study is to determine the significance of breathing during Korean dance, as it is externally expressed and technologically segmented, let alone the internal beauty of Korean dance. The results of this study show that the position of the body center and ASIS during the walking motion that uses breath was lower than that of the walking motion that does not use the breath. In addition, in each replacement of the knee joint and ankle joint, a narrow angle, in which bending is used a lot, appeared during the walking motion that uses the breath, but not during the walking gesture that does not use the breath. This occurred during the bending motion. In the first peak point, the vertical ground reaction force during the walking motion that uses the breath was higher than that during the walking motion that does not use the breath.
Biomechanical Alterations in the Lower limb Joints during the Punching Motion of Elderly Women after 12-Weeks of Taekwonaerobics Training
Yoo, Sil ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 637~645
DOI : 10.5103/KJSB.2009.19.4.637
The purpose of this study was to investigate the biomechanical alterations in the punching motion of 10 elderly women after 12 weeks of taekwonaerobics training. Seven infrared cameras(Qualisys MCU-240) and 2 force platforms(Kistler-9286AA) were used to acquire raw data. The results were as follows. First, the minimum joint angles of the lower limbs had a statistically significant difference between both the dorsiflexion/plantar flexion(1eft,
) and the inversion/eversion(both,
) from the ankle angle. There were differences in abduction/adduction(left,
) from the knee angle, as well as internal/external rotation(both,
) from the hip angle. Second, the maximum resultant joint moments of the lower limbs had statistically significant differences in the inversion/eversion moment from the ankle joint(both,
), the abduction/adduction moment(left,
) from the knee joint, and the internal/external rotation moment(right,
) from the hip joint. Third, the maximum resultant joint powers of the lower limbs had a statistically significant difference both in flexion/extension joint powers(both,
) and in abduction/adduction(both,
) from the hip joint, as well as abduction/adduction(left,
) from the knee joint, In conclusion, the elderly women were somewhat changed after 12 weeks of taekwonaerobics training.
Difference in Lower Extremity Landing Biomechanics between Male and Female Ballet Dancers During the Box Drop Landing
Choi, In-Ae ; Lim, Bee-Oh ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 647~653
DOI : 10.5103/KJSB.2009.19.4.647
The purpose of this study was to investigate the differences between female and male ballet dancers in anterior cruciate ligament injury risk factors during the box drop landing task. Nine female and nine male collegiate ballet dancers participated in this study. Kinematic and ground reaction data were collected and combined with inverse dynamics to estimate the knee extensor and abductor moment. EMG data from the biceps femoris and rectus femoris were used to estimate the ratio of quadriceps-hamstrings muscle activity. No gender differences in anterior cruciate ligament injury risk factors were found during the box drop landing task. A significant relationship was found between female and male ballet dancers in the knee flexion angle.
A Study on H-reflex Change and MVIC Change Depending upon Shouting Type
Jeong, Ik-Su ; Oh, Cheong-Hwan ; Lee, Dong-Jin ; Lee, Gun-Hee ; Lee, Jin ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 655~661
DOI : 10.5103/KJSB.2009.19.4.655
This study investigated the effects of different types of shouting actions on the strength of the human body. Both H-reflex and MVIC measures of the rectus femoris muscle were used to investigate effects on impact force and motor performance, in order to find optimum shouting methods. The H-reflex of the soleus muscle gave an electric stimulus to the curve of the knee that contains the tibial nerves. Surface electromyelography was used to collect muscle activity the amplitude increased 28% at action with shouting and 29% at the one immediately after short-time shouting than the one without shouting was. To assess the myoelectric activity of the rectus femoris, a surface electrode was attached to the right side of the lower extremity and to increase 10% and 1% depending upon shouting type. The findings were as follows. Shouting affected not only motor efficiency (H-reflex), but also the amplitude of MVIC, with a positive effect on increased muscle strength. Further comprehensive studies are needed to investigate the many variables of increased muscle strength for general purposes, for instance, shouting and breathing, brain waves, and so on.
Dynamics of Angular Running Turns in Foot Effectiveness
Shin, Seong-Hyoo ; Park, Hyun-Chul ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 663~669
DOI : 10.5103/KJSB.2009.19.4.663
The purpose of this study was to investigate the functional role of foot effectiveness when humans execute running turn maneuvers. Foot rotation angle at the starting turn and body angle at the vertical axis were analyzed through three-dimensional image analysis and ground reaction force analysis. Then, we created a simple equation: foot effectiveness = total foot rotation angle/total body rotation angle at the vertical axis. This equation made it possible to explain the dynamics of angular running turns. We analyzed data from running turns(0, 30, and 60) at average initial running velocities of 4.5, as well as rotations around the vertical axis during the running turns. As a result, the stance time, foot placement, and left and right force increased.
The Comparative Kinematic Analysis of a Volleyball Spike Serve
Park, Jong-Chul ; Back, Jin-Ho ; Lee, Jin-Taek ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 671~680
DOI : 10.5103/KJSB.2009.19.4.671
We performed a study to obtain kinematic data on the characteristics of spike serving techniques used by volleyball players, including other basic data that will be useful for in-field applications. We used three-dimensional videography to compare good tough serves and serve errors. The subjects were 3 left attackers whose spike serves were videographed (60 fileds/s). The three-dimensional coordinates were calculated using the direct linear transformation method and then analyzed using the Kwon 3D software program version 3.1. There was no difference in time elapsed. However, the vertical displacement of the center of body mass(CM) differed between the 2 types of serves: in successful serves, the CM tended to be lower, as did the maximum ball height at the time of hitting. Further, the higher the level of the hitting hand was at the moment of impact, the higher was the likelihood of scoring points. In good serves, the players tended to accelerate their CM movement just before jumping to hit the ball and descend rapidly at the moment of hitting. The hand speed along with ball velocity during the impact was proven to be higher in successful serves. Moreover, in successful serves, the shoulder angles increased to a greater extent while the elbow angles were maintained constant. This possibly resulted in faster and more precise serves. An important observation was that the angle of trunk inclination during the jump did not increase with the swing of the shoulders, muscle tendon complex.
A Neuromuscular Biomechanic Study of the Modulation of Corticospinal Excitability by Observation and/or Imagery of Action in Older Adults
Choi, Eun-Hi ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 681~688
DOI : 10.5103/KJSB.2009.19.4.681
To better delineate the changes in corticospinal excitability when older adults are asked to observe and/or imagine actions, 22 right-handed older adults without neurological abnormalities were included in this study. The amplitude and latency of motor evoked potentials (MEPs) by transcranial magnetic stimulation were recorded in the abductor pollicis brevis of the dominant hand during passive observation/imagery/active observation of slow/fast action of abduction of right thumb and also at resting state. Thus, active observation showed better changes than passive, but slow and fast action revealed no difference at all.
Changes in Balance Ability and Muscle Thickness of the Transverse Abdominis and Multifidus of Elderly Females after Eight Weeks of the Lumbar Stabilization Exercise
Ko, Dae-Sik ; Kim, Gwon-Yeong ; Lee, Chul-Gab ; Lee, Kyoung-Il ; Kim, Chan-Kyu ; Jeong, Dae-In ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 689~696
DOI : 10.5103/KJSB.2009.19.4.689
This study was conducted to examine the effects of the lumbar stabilization exercise (LSE) on fall prevention in elderly females (n = 21) by measuring changes in the isometric strength, multifidus, transverse abdominis muscle thickness, and posture stability index. The strength of isometric contraction was measured by the 3-D Pegasus system ; the thickness of the multifidus and transverse abdominis were measured by using Sonoace 6000C, and the posture stability index was measured using a computerized Biodex Balance System SD apparatus analysis. These results lead us to the conclusion that flexion and extension, left rotation on strength of isometric contraction, and thickness of the transverse abdominis (when released) statically increased. Overall, the anterior/posterior and medial/lateral elements in the posture stability index statically decreased, Consequently, the LSE should the prevent falls in elderly females.
Mechanical Energy Analysis for the Lower Limbs during Sit-to-Walk Movement in Elderly Women
Moon, Hoon-Kee ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 697~705
DOI : 10.5103/KJSB.2009.19.4.697
The purpose of this study is to elucidate the possible cause of falling owing to mechanical energy in elderly women as compared to young women when performing the sit-to-walk movement. Two groups participated in this study: 10 elderly women and 10 young women. We used a ProReflex MCU camera (Qualisis, Sweden) and ground reaction force to evaluate the mechanical work. The muscle power (W) showed the same low negative work in both groups in the extension phase of the knee and hip joints while varying the angular velocity and net muscle moment of force. Elderly women, in particular, showed lower negative work. In mechanical work (J), the knee and hip joints of both groups showed the same amount of negative work in the extension phase. In the hip joint, elderly women showed lower negative work results in each phase. These result showed the possible reasons of falling for elderly women according to the weakness of the thigh muscle of the hip joint during the sit-to-walk movement.
Analysis of Kinematic Parameters between Skilled and Less Skilled Female Javelin Throwers
Lee, Young-Sun ; Ryu, Ji-Seon ; Kim, Tae-Sam ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 707~717
DOI : 10.5103/KJSB.2009.19.4.707
The purpose of this study was to investigate the kinematic parameters between a stalled group and a less skilled group of female javelin throwers, in order to record differences in their support landing and release phase. For this, the female athletes were divided into two groups: the sidled group, which consisted of javelin throwers with records over 45m, and the less skilled group, which consisted of javelin throwers with records below 45m. During the release phase, the horizontal velocity differed significantly(p<.05) between the two groups. The projection angle at the release moment also differed significantly(p<05) between the groups. The knee angle of the support leg differed significantly(p<.05) between the two groups at E1, E2, and E3, but there was no difference at E4. The shoulder angle differed significantly(p<.05) between the two groups only during the landing of the power leg.
Improving Evaluation of the Basket-to-Handstand Mount by a Technical Training Program on Parallel Bars
Lee, Chong-Hoon ; Back, Jin-Ho ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 719~728
DOI : 10.5103/KJSB.2009.19.4.719
In this study, a training program was conducted to improve the performance of the basic movement of the basket-to-handstand mount. After completion of the training program, the kinematic comparison of the before and after effects were investigated to provide scientific data about this technique. It is recommended that during P1, the center of body mass at the back should push the hip joint to flex quickly, and the shoulder joint should be maintained at a maximum angle. During P2, the body's center of mass must be accelerated so as to create enough momentum to rise efficiently for this, quick extension of both the hip and the shoulder is required. For safety during P3, it is advised that the speed upwards must be increased and that the hands, shoulders, and hip joint must be extended, as in the posture of a handstand. These results stress to coaches the importance of the bodies speed during the ascent in the motion.
The Effects of Accuracy on Skill Level and Eye-Tracking Type in Golf Putting
Woo, Byung-Hoon ; Kim, Chang-Won ; Park, Yang-Sun ; Lee, Kun-Chun ; Lim, Young-Tae ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 729~738
DOI : 10.5103/KJSB.2009.19.4.729
The purpose of this study was to analyze the impact accuracy and kinematic parameters of skill level and eye-tracking type during putting strokes. For comparison, five elite golfers and five novice golfers participated in this study. Three-dimensional kinematic data were collected for each subject while 10 putting trials were performed for each skill level and eye-tracking type. The APAS system was used to compute the impact accuracy and kinematic parameters of putter heads. The putting stroke was divided into three phases: back swing, downswing, and follow-through. The findings indicated that significant differences were found in skill level as it affected the rate of success. For impact accuracy and the displacement of putter heads, a significant difference was found for the skill level, particularly in backs-wing and follow-through. In addition, the displacement of the putter head had a greater influence on stroke accuracy than on velocity.
Kinematic Analysis of Jerk Motion during Successful and Failed Trials of a Male Weight lifter -Case Study of an Olympic Gold Medalist-
Park, Tae-Min ; Ryu, Ji-Seon ; Yoon, Suk-Hoon ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 739~748
DOI : 10.5103/KJSB.2009.19.4.739
The purpose of this study was to compare successful and failed trials of the dean and jerk exercise performed by an 2008 Beijing Olympic gold medalist. One successful and one failed trial of an Olympic gold medalist (2008 Beijing Olympic 77 kg event) were investigated for this study. A three-dimensional motion analysis was performed, using three digital camcorders (SF: 6Hz). The events were recorded during the 89th Korean National Athletic Games. After analyzing the jerk motion, the following results were found. The successful trial revealed a shorter performance time at Phase 1 and a longer one at Phase 3 and Phase 4 as compared to the failed trial. The vertical displacement of the knee in failed trial was lower than that m the successful one. The differences in the vertical velocity of barbell and knee between the trials were seen at Phase 3 and Phase 4. A faster COM inferior velocity was seen in the successful trial at Phase 3. A more flexed knee angle was seen in the failed trial as compared to the successful trial at E3.
Kinetic Analysis of the Movement of Soft Tennis Forehand Middle Volley
Lee, Sung-Hee ; Heo, Jeong ; Kim, Hun-Soo ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 749~759
DOI : 10.5103/KJSB.2009.19.4.749
The purpose of this study was to provide basic information for improving a soft tennis forehand middle volley technique based on kinematic and kinetic analyses of volleys performed by four male national tennis players(
years). The results are as follows. The first phase of the stroke was the longest, covering 64.7% of the stroke time. The displacement of the center of gravity was 48.1% to the right and 54% to the front in the first phase. When impacted, the elbow joint showed the highest average velocity, 3.67m/s, and the upper arm segment displayed the highest angular velocity,
. The average of the elbow angle and the ball velocity were
and 18.9m/s, respectively. In the ground reaction force, the left and right foot forces in both the x and y directions showed a statistically significant difference. This result seems to indicate that when the left foot is pushed to the right, the force of the right foot is proportional and symmetrical to the left, serving as a supporter.
Kinematic Analysis of Hurdling of Elite 110-m Hurdlers
Lee, Jin-Taek ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 761~770
DOI : 10.5103/KJSB.2009.19.4.761
The purpose of this study was to observe the kinematic patterns of hurdling by domestic hurdlers and elite hurdlers from other countries in particular, we studied the hurdling motion and joint angles at the third hurdle in 110-m hurdle races. There were slight differences in the following variables at takeoff and landing: angle of the center of gravity(elite hurdler,
), angle variables the body angle(elite hurdler,
), the angle of trunk inclination(elite hurdler,
), and the hip angle(elite hurdler,
A Comparative Analysis on Changes of Foot Pressure by Shoe Heel Height during Walking
Park, Jong-Jin ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 771~778
DOI : 10.5103/KJSB.2009.19.4.771
We aimed to determine the effect of heel height on foot pressure by comparing and analyzing data on foot pressure in shoes with different heel heights. Qn the basis of a previous study, we selected 3cm and 7cm as the shoe heel heights preferred by female college students. We divided 10 female students into forefoot and hindfoot to measure vertical force, maximum pressure, and average pressure. The average pressure on the forefoot was higher and that on the hindfoot was lower in the case of 7cm high-heeled shoes. The maximum pressure on the forefoot was significantly higher in the case of the 7cm heel height (p<.05). The vertical force, maximum pressure, and average pressure on the hindfoot were also significantly higher in the case of the 7cm heel height (p<.05). The results showed that wearing 7cm high-heeled shoes exerted greater maximum pressure on the forefoot and greater vertical force, maximum pressure, and average pressure on the Hndfoot. This leads to increase in confining pressure caused by high pressure distribution over the forefoot and increase in the pressure on the hindfoot, which may cause deformation of toes and heel pain over a long period. Therefore, female college students who wish to wear high heels are recommended to wear 3cm high-heeled shoes rather than 7cm high-heeled shoes.
Development of a Program That Computes the Position of the Instantaneous Center of Rotation on the Basis of Experimental Data(I)
Park, Jin ; Shin, Ki-Hoon ;
Korean Journal of Sport Biomechanics, volume 19, issue 4, 2009, Pages 779~791
DOI : 10.5103/KJSB.2009.19.4.779
The purpose of this study is to develop a program that computes the position of the instantaneous center of rotation while an object moves in a circular motion. For this study, a mathematical algorithm was developed and implemented on the experimental data. Data for pitching (40m carry) and putting (4m) strokes were obtained from a skilled female golfer. A computer program (Centering 1.0) calculated the experimental data and found the radius of the instantaneous center of rotation. When the data were taken broadly, the program produced an error distance of radius. When the data were divided gradually, the program produced a very close instantaneous center of rotation. On comparing pitching and putting strokes, putting was found to have a greater radius than pitching. The instantaneous centers of rotation of putting were not in the golfer's body rather, they were 3m away from the club head. The Centering 1.0 program can calculate the instantaneous center of rotation with at least three sets of experimental data.