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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
The Relationship between the Distance and Release Parameters in Korean Female Javelin Throwers
Kim, Tae-Sam ; Ryu, Ji-Seon ; Lee, Soon-Ho ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 131~140
DOI : 10.5103/KJSB.2012.22.2.131
This study was to investigate the relationship between the distance and projection factors, angle factors of javelin in women's javelin throwing. The data were collected in the 2011 National Sports Festivals for 11 players. Three-Dimensional motion analysis using a system of 4 video cameras at a sampling frequency of 60 fields/s was performed for this study. The factors of release conditions calculated using Matlab 2009a program. The statical analysis on the records(n=42) included mean and standard deviation of the mean(SD), Pearson's product moment correlation coefficient(SPSS Version 16.0 for Windows). There was a statistically significant positive relationship between the records and release velocity(r=.866, p<.01), height(r=.433, p<.01) and height rate(r=.340, p<.05). The attitude angle, release angle, and attack angle showed not a statistically significant relationship between the records. The medial-lateral tilt angle of javelin showed not a statistically significant relationship between the records, but the yaw angle of javelin(r=.549, p<.01) showed a statistically significant positive relationship between the records.
Comparative Analysis of Plantar Pressure between Skilled and Unskilled Players during Hockey Penalty Stroke
Lee, Jae-Youl ; Lee, Joong-Sook ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 141~150
DOI : 10.5103/KJSB.2012.22.2.141
This study aims to provide the basic biomechanical data on the average, maximum and distribution of plantar pressure during hockey penalty stroke by comparing five skilled and five unskilled players. Following are the conclusions. First in the case of average and maximum planter pressure during penalty stroke, the skilled players showed higher pressures at the moment of left foot landing in rear plantar of left foot and fore, rear plantar of right foot compared to the unskilled players. Also at the moment of impact, the skilled players showed higher pressures in fore, rear plantar of left foot and fore plantar of right foot compared to the unskilled. The analysis drew the conclusion that the skilled players move their center of body from fore, rear plantar of right foot to fore, rear plantar of left foot at the moment of left foot landing and impact in order to perform a quick and strong shooting. Second in the case of plantar distribution, as the skilled players put over 70% of their weights on left foot, they showed overall higher plantar pressure distributed on the outer fore, mid and rear parts of left foot plantar, in contrast with the unskilled players who showed about 50/50 distribution of weights on their right and left foot. The analysis concluded that such distribution was shown because the skilled players transferred their weights from the right to left foot effectively while the unskilled players could not do so.
A Study on the Structure of Three Dimentional Spine, Pelvic Deviation and Foot Pressure in Golf Players
Yang, Dae-Jung ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 151~158
DOI : 10.5103/KJSB.2012.22.2.151
The purpose of this study was to investigate variables of significantly difference as the structure of the spine, pelvic deviation and foot pressure between undergraduates and golf player subjects. The subjects of study were composed of 20 male golf players and 20 male undergraduates. Both groups were right handed persons. The measurement tools of this study were Formetric 4D(Diers, Germany) which is a three dimensional measure. The result are the follows: there were a significant difference between golf players and general students of trunk imbalance, pelvic tilt, pelvic torsion, pelvic rotation, surface rotation, lumbar lordotic curve, foot pressure(fore & behind foot), weight distribution(right & left foot). In conclusion, golf players might cause transform of spine and foot pressure due to golf exercise for several years. Such as imbalance affect to induce functional impairment and pain of musculoskeletal system, and appropriate evaluation and treatment were necessary for golf players.
The Kinematic Analysis of Gliding Type and Delivery Phase in Each Trails during Shot-Putting - Focusing on Lee, Hyung-Keun, Player in Men's High School Youth Group -
Kim, Tae-Sam ; Ryu, Ji-Seon ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 159~171
DOI : 10.5103/KJSB.2012.22.2.159
The purpose of this study was to provide information about kinematic variables of the gliding and delivery motion of Hyung-Keun Lee, a high school shot putter who was ranked 1st at the 2011 National Sports Festivals. Three-Dimensional motion analysis using a system of 4 video cameras at a sampling frequency of 60 Hz was conducted during shot-putting events at the 2011 National Sports Festivals. During the gliding and delivery phase of the player the results showed following characteristics; 1) The gliding technique types of the player appeared to be the short-long technique as the gliding and stance length ratio were
%, respectively. In addition, the trajectory of shots during the gliding and delivery phase showed different trajectory patterns with "S-shaped" type of elite players due to the deviation from a central axis of the APSS (athletic-plus shot system). 2) The horizontal velocity of COG made from gliding should maintain the velocity during transition and release phase, but the player showed a small momentum for a gradual decrease of velocity. 3) Therefore, the player requires to adjust an appropriate ratio between gliding and stance length with a strong muscle power at the trunk, throwing arm, and the lower extremity during gliding and delivery phase.
The Kinematic Analysis of Fouette A La Second in Cheerleading
Yeon, Eun-Jung ; Ryu, Jae-Kyun ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 173~181
DOI : 10.5103/KJSB.2012.22.2.173
The purpose of this study was to research on the movement of Fouette A La Second which was a type of turning movements on cheerleading. This research was conducted for helping cheerleaders to improve their overall skills. The three cheerleading national team members were participated in this research and the movements of Fouette A La Second were recorded with 6 digital motion master 60 video cameras, operating at a sampling frequency of 60 fields/sec. Six out of ten turning motion data were collected and analyzed with Kwon3D XP. The results were as follow: 1) The subject A's Releve motion was not executed precisely because of the COG's unstability. So she was required to improve the balancing ability. 2) The subject B could not execute the precise A La Second motion because of subject B's large hip angle. By tracing the projection of B's right toe on x-y plane, the subject made an elliptical orbit. Because B did not have a proper turning skills she needed to improve the muscle power and flexibility. She also needed to move quickly from Releve to Plie movement. 3) The subject C could not execute the Plie movement precisely, so she could not turn her body correctly around a certain spot. The subject C needed to decrease the knee angle at the Plie motion.
Analysis of Plantar Foot Pressure in Skilled and Unskilled Player's during a Free Throw in Basketball
Kim, Chang-Hyun ; Lee, Joong-Sook ; Jang, Young-Min ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 183~191
DOI : 10.5103/KJSB.2012.22.2.183
The objective of this study was to evaluate the plantar foot pressure of skilled and unskilled players during a free throw. The experiment performed here in measured the movement route of the mean foot pressure, maximum foot pressure, and center of pressure in four event zones (ready, maximum knee flexion, release event, and maximum knee extension) for both groups while they were wearing the plantar foot pressure measurement equipment under identical conditions. The major findings are as follows. When getting ready (RD) during a free throw, the skilled player group had higher mean and maximum foot pressures, although neither variable showed significant differences statistically. For the maximum knee flexion (MF) during a free throw, the skilled player group had higher mean and maximum foot pressures, but only the mean foot pressure significantly differed statistically. For the release event (RE) during a free throw, the unskilled player group had higher mean and maximum foot pressures, but only the mean foot pressure significantly differed statistically. During the maximum knee extension (ME) of a free throw, the unskilled player group had a higher mean foot pressure, and the skilled player group had a higher maximum foot pressure. No significant correlation was found between the two groups. For the skilled player group, movement towards the center of pressure showed a stable form that moved from the rear to the front and from side to side during a free throw. For the unskilled player group, movement towards the center of pressure was unstable, which made it impossible to move from the rear to the front and from left to right.
The Comparison of Electromyographic Ratio of Serratus Anterior and Upper Trapezius According to Exercise Position and Shoulder Flexion Angle during Scapular Protraction Exercises
Koh, Eun-Kyung ; Weon, Jong-Hyuck ; Jung, Do-Young ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 193~199
DOI : 10.5103/KJSB.2012.22.2.193
The purpose of this study was to investigate the activities of the serratus anterior (SA) and upper trapezius (UT) muscles during scapular protraction exercise with a dumbbell. Twenty-one healthy subjects with no medial history of shoulder pain or upper extremity disorders were recruited for this study. Subjects performed scapular protraction at
shoulder flexion with a dumbbell in supine and standing positions. The activities of the SA and UT were measured via surface electromyography (EMG) during 4 scapular protraction exercises. A 2 (angle)
2 (position) repeated-measures analysis of variance (ANOVA) was used to compare the normalized activities of the SA and UT and the UT/SA ratio. The results showed that activities of both the SA and UT were the highest for the scapular protraction exercise at
shoulder flexion in the standing position. However, the UT/SA ratio was the lowest for the exercise at
shoulder flexion in supine position. Therefore, for selective activation of the SA muscle, we recommend performing the scapular protraction exercise with a dumbbell in the supine position at
Effects of Six-week Resistance Exercise using an Outdoor Knee Extension Machine on Function and Structure of the Knee Extensor Muscles
Choi, Dong-Sung ; Kim, Jin-Sun ; Kim, Dong-Il ; Jeon, Justin-Y. ; Won, Young-Shin ; Lee, Hae-Dong ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 201~208
DOI : 10.5103/KJSB.2012.22.2.201
The purpose of this study was to investigate the effect of leg extension exercises performed on outdoor resistance exercise machines on knee extension muscle strength and quadriceps muscle group cross sectional area (CSA) in elderly women. Two groups were recruited for this study, including an exercise group (EG: n=13,
yrs) and a control group (CG: n=5,
), In all subjects, maximum isometric and isokinetic muscle strength of knee flexion and extension were measured using an isokinetic dynamometer (Cybex(R) Humac Norm Testing & Rehabilitation System, USA). Quadriceps muscle group CSA were measured using MRI (Philps, Intera 1.5 T, NE Netherlands). The results of this study showed that post-intervention isometric knee extension peak torque value were higher than pre-intervention measures in the EG. However, the EG did not show improvement in quadriceps muscle group CSA, Also, no differences in the shift of optimal knee joint angle were observed between pre and post-intervention exercise. Outdoor leg extension exercise showed small increases in muscle strength in comparison to other resistance training exercises. The results of this study suggest that because outdoor leg extension exercise machines lack a progressive loading mechanism, significant increases in muscle strength may not be obtained.
Development and Verification of Treatment Programs by Turn and Roll Types to Improve the Function of Vestibular System
Park, Yang-Sun ; Kang, Sung-Ho ; Lim, Young-Tae ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 209~217
DOI : 10.5103/KJSB.2012.22.2.209
The purpose of this study was to develop a turn-type treatment program which applies the principle of spotting and a roll-type treatment program that induces off-vertical axis. 29 collegiate students volunteered for this study. 12-week treatment programs were applied to both 15 students for turn-type treatment group and 14 students for roll-type treatment group. As an analytic tool, eye camera was employed to verify the treatment programs for a stimulus upon a turn, recovery after a stimulus upon a turn, and nystagmus that affects a vestibular system. Two-way ANOVA with repeated measures was applied to see the significant differences between the treatment groups, and between the test periods. For Post-Hoc Test, paired t-test was used to within the group and independent t-test was used to between the groups. The results indicated that roll-type treatment training has maximized a stimulus on nystagmyus during the stimulus by a roll. Turn-type treatment training has maximized a stimulus on nystagmyus right after a stimulus by a roll and significantly decreased the intensity of nystagmyus during the recovery. Both turn and roll type treatments have reduced the recovery time which from nystagmyus to a normal status. Roll-type treatment has showed a much shorter recovery time for nystagmyus than the roll-type treatment has. Based on the results of treatment programs developed in this study, we expect the treatment programs can be applied to treat dizziness and to improve the function of vestibular system as a rehabilitation tool.
Effects of Induced Fatigue of Ankle Joint Muscle on the Capability and Recovery of Postural Control during Single-Leg Stance
Youm, Chang-Hong ; Kim, Tae-Hyeon ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 219~228
DOI : 10.5103/KJSB.2012.22.2.219
The purpose of this study was to investigate how induced fatigue of the ankle joint muscles affects the capability and recovery of postural control during single-leg stance in healthy adults. The study population included 22 randomly recruited men and women. Postural control was performed on single-leg stance with eyes open. Ankle joint muscle was fatigued by repeated heel raises. According to the results of this study, for the anteroposterior variables, both men and women showed significantly increased center of mass velocity and decreased center of pressure 95% edge frequency immediately after fatigue. For the mediolateral variables, both men and women showed significantly increased center of mass velocity and decreased center of pressure 95% edge frequency immediately after fatigue. For the total variables, both men and women showed significantly increased center of mass averaged-velocity immediately after fatigue, and also, the center of pressure 95% confidence ellipse area significantly increased in women. Postural control variables were not significantly different for men and women at any time (Pre, P0, P10, and P20). In conclusion, the gender does not affect the capability and recovery after induced fatigue of ankle joint muscles. The effect of fatigue found for the anteroposterior and the mediolateral variables in both men and women. Furthermore ankle joint muscle fatigue led to change of postural control strategy from an ankle joint strategy towards a hip joint strategy. These changes are believed to damage postural control. The ankle joint muscle recovered from fatigue within 20 min during single-leg stance.
The Differences in Foot Type According to Major in Left and Right Foot for Female College Students
Yi, Kyung-Ock ; Kim, Nam-Hee ; Kim, You-Ryun ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 229~236
DOI : 10.5103/KJSB.2012.22.2.229
The purpose of this study is to analyze the differences in foot type of female college students according to academic major in both feet. The subjects for this study were 216 female students who took liberal arts classes in Seoul. Dependent variables were students' field of study -specifically whether or not they majored in physical education. Analysis of students' foot type and Malalignment Syndrome were measured using Resting Calcaneous Stance Position (RCSP). There were five categories for RCSP angle: Severe Pes Planus (<
), Pes Planus (
), Pes Rectus (
), Pes Cavus (
), Severe Pes Cavus (>
analysis was used for statistical analysis. RCSP for all subjects (432 feet) occurred at the following frequency: Pes Planus(43.9%), Pes Rectus(43.8%), and Pes Cavus(12.3%). These levels were different for physical education majors, with Pes Planus at 42.6%, Pes Rectus at 49.4%, and Pes Cavusat 8.0%. Non-physical education majors exhibited Pes Planus at 45.0%, Pes Rectus at 39.9%, and Pes Cavus at 15.1%. 15.3% (33 subjects) of all students had Malalignment Syndrome. In conclusion, 56.2% of female college students had a foot deformity. There was nearly four times more Pes Planus than Pes Cavus. According to these results, exercise can be prescribed to alleviate foot deformities, especially supination. Severe pronation and supination problems appeared less amongst students not majoring in physical education. Thus, although exercise might be one cause of foot deformity, it can also help resolve problems with over-supination. Further study will be needed to understand and resolve the specific mechanism of over-supination.
The Comparative Analysis on Mechanical Property Test of Carbon Nanotube-based Shock Absorbers
Kim, Jong-Woo ; Chae, Woen-Sik ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 237~242
DOI : 10.5103/KJSB.2012.22.2.237
The purpose of this study was (a) to develop carbon nanotube-based shock absorbers for reducing potentially harmful impact forces and excessive foot pronation, and (b) to briefly determine how the effects of carbon nanotube-based shock absorbers on biomechanical variance during drop landing. A university student(age: 24.0 yrs, height: 176.2 cm, weight: 679.5 N) who has no musculoskeletal disorder was recruited as the subject. Hardness, specific gravity, tensile strength, elongation, 100% modulus, tear strength, split tear strength, compression set, resilience, vertical GRF, and loading rate were determined for each material. For each dependent variable, a descriptive statistics was used for different conditions. The property test results showed that tensile strength, tear strength, split tear strength, compression set, and resilience in carbon nanotube-based shock absorbers were greater than general Ethylene Vinyl Acetate(EVA). These indicated that resistance against variable strength in developed carbon nanotube-based shock absorbers were greater than general EVA. In vertical GRF of CNTC was less than those of EVA during drop landing and loading rate of CNTC was greater than EVA. It seems that the use of CNT can be a effective way of reducing and controlling shock from impact.
Development of an Impact Force Measurement Device with an Attached Strain Gauge
Jeong, Ik-Su ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 243~251
DOI : 10.5103/KJSB.2012.22.2.243
The purpose of this study was to develop an impact force measurement device in order to facilitate the acquisition of quantitative data for the analysis of various sporting events. The device was designed to include cylindrical aluminum supports of 220 mm diameter, which allows mounting and dismounting of the device on walls and frames. In addition, a hard sponge for impact absorption, as well as 4 springs, were attached to the plate. Both were attached to prevent psychological variables and injuries. When a subject applies force on the device, accurate data about the maximum repulsive force is acquired in real time, with a lag of only 0.001 s. The device was calibrated in four steps: (1) increase, (2) increase, (3) increase-decrease, and (4) increase-decrease. The maximum relative expanded uncertainty was 0.166%, indicating that the impact force measurement was sufficiently reliable. The proposed device can be applied to various sporting situations and is expected to be useful for studying kinetics.
Biomechanical Analysis of a Smartphone Task with Different Postures
Kim, Dong-Soo ; Chae, Woen-Sik ;
Korean Journal of Sport Biomechanics, volume 22, issue 2, 2012, Pages 253~259
DOI : 10.5103/KJSB.2012.22.2.253
The purpose of this study was to determine how smartphone use posture affects biomechanical variables and muscle activities. Eleven university students(age:
kg) who have no musculoskeletal disorder were recruited as the subject according to having experience in using the smartphone for more than one year. Angular velocity, muscle activity, and thumb finger pressure were determined for each trial. For each dependent variable, a one-way analysis of variance (ANOVA) with repeated measures was performed to test if significant difference existed among different three conditions (p<.05). The result showed that rotational angular velocity of the first metacarpal were increased in DESK posture compared with STAND posture during SU phase. The average nEMG values of FDI(First dorsal interosseous) were less in SIT and DESK posture compared with STAND posture during SR phase. These indicated that smartphone postures may effect the thumb ROM(Range of motion) and muscle activity. This has led to suggestions of the need for further kinetic and EMG analyses to evaluate best assess and characterize with smartphone use.