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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
Comparisons of Pflugbogen's Biomechanical Characteristics to Develop Interactive Ski Simulator
Koo, Do-Hoon ; Lee, Min-Hyeon ; Kweon, Hyo-Sun ; Hyun, Bo-Ram ; Eun, Seon-Deok ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 189~199
DOI : 10.5103/KJSB.2014.24.3.189
The purpose of this study was to compare pflugbogen's biomechanical characteristics between on the ski simulator and snowed ski slope to develop interactive ski simulator. Nine ski instructors(sex: male, age:
, body mass:
) belong to Korean Ski Instructors Association participated in this research. 24 Infrared cameras for snowed ski slope experiment and 13 infrared camera for ski simulator experiment were installed near by path of pflugbogen. The participants did pflugbogen on the snowed ski slope and the ski simulator both. During the experiment, the participants weared motion capture suit with infrared reflective makers on it, and plantar pressure sensors in ski boots, so that ski motion and plantar pressure data were collected together. Displacement of COG(center of gravity) movements, trunk flexion/extension angle, adduction/abduction angle, and plantar pressure data were significantly different between on the simulator and ski slope. However, percentage of time of COG movement in the phases during medial/lateral and anterior/posterior movement were not significantly different. Findings indicate that the difference between two groups occurred because the ski simulator's drive mechanism is different from ski motion on the slope. In order to develop the ski simulator more interactively for pflugbogen, the ski simulator's drive mechanism need to be reflected 3D motion data of pflugbogen on the slope that were purposed in this research.
Comparisons of Center of Mass and Lower Extremity Kinematic Patterns between Carved and Basic Parallel Turn during Alpine Skiing
Kim, Joo-Nyeon ; Jeon, Hyun-Min ; 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 3, 2014, Pages 201~207
DOI : 10.5103/KJSB.2014.24.3.201
This study investigated the center of mass and lower extremity kinematic patterns between carved and basic paralell turn during alpine skiing. Six experienced skiers (age:
, body mass:
) participated in this study. Each skier were asked to perform carved and basic paralell turn on a
groomed slope. Each turn was divided into the initiation phase, steering phase 1 and 2. The results of this study show that the carved turn spent significantly less running time than basic paralell turn at all three phases (p<.05). Also vertical displacement of the center of mass was significantly greater in carved turn at all three phases, whereas inward leaning angle of the center of mass was significantly greater in carved turn at the steering phase 1 and 2 (p<.05). Bilateral knee and hip joint angle were significantly greater in basic paralell turn at the initiation phase and the steering phase 2 (p<.05). On the other hand, left knee and hip joint angle were significantly greater in basic paralell turn at the steering phase 1 (p<.05). In order to perform successful carved turn, we suggest that skiers should coordinate bilateral knee and hip joint angles to adjust the center of mass, depending on three ski turn phases.
The Effect of 8 Weeks Athletics Class on Sprint Start Motion
Lee, Jin-Taek ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 209~216
DOI : 10.5103/KJSB.2014.24.3.209
The purpose of this study was to explore the effect of 8 weeks after school classes of track sports on students' start motion through kinematic variables. 30 students in D National university of education participated for this study. These students divided into two groups, 17 students for experimental group and 13 students for control group. The two groups participated in general athletic class as common class, and the experimental group participated in after school class additionally. The general class taught track and jump skill for 3 hours a week, and the after school class taught only athletic running skill for 30 minutes a week. Pre and post test assessed to assess students' kinematic changes. Findings indicated that velocity and step rate were increased, and contact time, step length, displacement of center of mass were decreased in the experimental group. In the control group, early velocity, knee/hip angle velocity were increased, and contact time, step length, displacement of center of mass were decreased. In conclusion, the students who only participated in general class, could not maintain athletic skills obtained from the class. However, students who participated in both general and after school class accomplish athletic start skill. This is because Continuous learning effect helped students keep the skill and did not lose the skill. Thus, in order for students to learn specific sport skills, joining after school class with general class together is recommended.
The Relationship between the Distance and Kinematical Parameters of Javelin in Korean Male Javelin Throwers
Kim, Woo-Jin ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 217~227
DOI : 10.5103/KJSB.2014.24.3.217
The purpose of this study was to investigate the relationship between distance and factors of javelin in korean male's javelin throwing. To accomplish this purpose, the analyzed trail selected total 29 trails (subjects 9) recorded more than 65 m in the 93rd National Sports Festival. The Kwon3D 3.1 version was used to obtain the three dimensional coordinates about the top, grip, end of javelin. And the kinematic data such as projection factors and direction angle of javelin calculated using Matlab2009a program. The statical analysis on the records (n=29) were used to Pearson's product moment correlation coefficient. There was a statistically positive relationship between the records and horizontal velocity (r=.866,
<.01), height (r=.541,
<.001), height rate (r=.373,
<.05) and horizontal displacement of javelin (r=.749,
<.01), but the medial/lateral velocity showed a negative relationship to r=-.663 (
<.01). The attack and yaw angle showed not a significant relationship between the records, but the medial-lateral tilt (E1:r =-.557 [p<.01)] E2:r=-.629 [
<.01], E3:r=-.528 [
<.01]) and attitude angle (E2:r=-.629 [[
<.01], E3:r=-.619 [
<.01]) of javelin showed a negative relationship between the records, as well as the projection angle of javelin (r=-.419,
<.05) showed a negative relationship between the records.
The Effect of Attention Focusing Strategies on the Speed and Segment Coordination Characteristics of Taekwondo Hand Techniques
Kang, Sungchul ; Kim, Kitae ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 229~238
DOI : 10.5103/KJSB.2014.24.3.229
This study comparatively analyzed the speed and segment coordination characteristics of Taekwondo hand techniques, while different attention focusing strategies were utilized. Ten elite Taekwondo poomsae athletes participated, and three different strategies (no focus, target focus, body focus) were utilized in random order. The hand velocity and upper body segment coordination characteristics were analyzed, with the following results. First, the maximum magnitudes of the hand velocity differed between the focus conditions for the Araenaereomakgi and Momtongjireugi techniques. Second, the angular velocity and kinetic energy transfer patterns of the segments differed between the focus conditions, and in the case of the body focus condition, the movement was more correct according to the theory. Third, the shoulder and elbow joint coordination patterns differed between the focus conditions, with more efficient movement shown with the body focus condition. In conclusion, we confirmed the potential of effectively using an attention focusing strategy in a taekwondo teaching situation. However, the effect on the movement coordination and results of the movement could be changed by a difference in the cue provided or the type of the task. In addition, depending on the task, the attention focusing strategy could affect the efficiency of the movement. Therefore, coaches and masters of Taekwondo will have to constitute determine the appropriate attention focusing cues based on the task.
A Study of Motor Expertise about Kinematic and Kinetic Characteristics of Lower Extremity in the Seokmun Ilwol Martial Art Yin-yang Bo Gait Pattern
Park, Bok-Hee ; Kim, Ky-Hyoung ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 239~248
DOI : 10.5103/KJSB.2014.24.3.239
The purpose of this study was to quantify kinematic and kinetic characteristics of Yin-yang Bo gait according to their motor expertise, one of the Seokmun Ilwol martial art gait patterns. Yin-yang Bo gait pattern shows initial forefoot contact instead of heel contact, and increased time of stance phase time, internal-external rotation of ankle-knee-hip joints and pelvic. It aims to produce and store the more energy through continuous homeostasis of center of gravity (COG) and performance of stretch-shortening cycle. Some of these characteristics also were similar to the gait modification strategies for reducing knee adduction moment such as toe-out progression, medial thrust, internal rotation of hip joint. To identify the characteristics, four factors of expert Yin-yang Bo gait performance group were compared to that of none expert group; 1) angles of COG displacement and rotation 2) distal joint pre-rotation in internal-external rotation of ankle-knee-hip joints and pelvic, 3) invariability pelvic potential and pelvic segment total energy 4) knee abduction moment. Six healthy(three male) subjects participated in the experiment to perform Yin-yang gait pattern. Three-dimensional and force plate data were collected. Kinematic and kinetic data were compared between two groups using t-tests. Results showed that 1) the peak point of COG internal rotation angle was reduced in expert group, 2) kneeexternal and hip joint -internal and pelvic rotation angle peak frames were more near points in expert group.
The Comparative Analysis of Gait Safety between Elderly Female and Adult Female
Yi, Jae-Hoon ; Chang, Jae-Kwan ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 249~258
DOI : 10.5103/KJSB.2014.24.3.249
The purpose of this study was to investigate the different patterns of the lower limb between elderly and adult females to reduce the rate of falls. Ten old females(age:
) and ten adult females(age:
) were participated in this experiment. The gait motions were captured with Qualisys system and variables were calculated with Visual-3D. The following results were found. The elderly female group showed bigger inclination angle between COM and COP than the adult female group so that the dynamic stability was reduced in walking for the compensation with a bigger stride width. The elderly female group ensure for the necessary forward movement of COM in order to replace the decreased function of ankle and knee joint. If the distance between COM and COP is closer and the energy reduction of a specific joint is reduced, they could prevent the elderly female's falling rate by strengthening of muscles which were related the extension of ankle joint.
The Relationship between Standing Posture Biomechanics and Physical Fitness in the Elderly
Yi, Kyung-Ock ; Choi, Kyoo-Jeong ; Kim, Soyoung ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 259~267
DOI : 10.5103/KJSB.2014.24.3.259
The purpose of this study was to find the relationship between standing posture biomechanics and physical fitness in the elderly. Physical fitness variables and postural variables for 227 (140 women and 87 men) elderly individuals were tested. Physical fitness tests (Korean Institute of Sports Science, 2012) included 3m sit, walk, and return, grip test, 30 second chair sit and stand, sit and reach, figure 8 walks, and 2 minute stationary march. Postural biomechanics variables included resting calcaneal stance position (RCSP), shoulder slope, pelvic slope, knee flexion angle, leg length difference, thoracic angle, and upper body slope. In statistical analysis, multiple regression was conducted by using stepwise selection method via SAS (version 9.2). Analysis for both men and women revealed significant relationships between physical fitness and age, upper body slope, knee flexion angle, leg length difference. Pelvic and thoracic angle were only related to figure 8 walking and sit and reach in women, while RCSP and shoulder slope had no relationship with any physical fitness variables.
Effects of the Functional Garment Wear on Cobb's Angle and COM of Trunk and Pelvic during Gait for Adolescent Idiopathic Scoliosis Patients
Park, Yang-Sun ; Lim, Young-Tae ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 269~275
DOI : 10.5103/KJSB.2014.24.3.269
The purpose of this study is to develop functional garment wear for patients with adolescent idiopathic scoliosis (AIS) and to analyze changes in Cobb's angle and the COM of the body and the pelvis during gaits in order to identify the effects of the functional garment wear. The subjects of the study were 9 patients with adolescent idiopathic scoliosis, who wore the functional garment wear for 12 weeks 12 hours a day. As for the research methods, the scoliotic angle was measured using Cobb's angle, and the shoulder angle and the COM of the body and the pelvis during gaits for the AIS patients were calculated using five high speed infrared cameras. As a result of the study, it was found that the scoliotic angle (Cobb's angle) was reduced significantly and that the smaller the original scoliotic angle, the greater the effects. As for the shoulder motion angle, a significantly larger angle was found 12 weeks after wearing the functional garment wear, and particularly, larger shoulder motion (activity) was observed at the phase of right heel contact. As for the motion of the body and the pelvis, the moving ranges were significantly reduced after wearing the functional garment wear for 12 weeks, which stabilized gait in the patients with adolescent idiopathic scoliosis.
A Comparative Study on the Kinetic Factors in Taekkyon Nakcyguri with and without Hip Bending
Oh, Seong-Geun ; Yi, Jae-Hoon ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 277~285
DOI : 10.5103/KJSB.2014.24.3.277
Nakcyguri is one of the offensive weapons most often used in Taekkyon games, The purpose of this study was to investigate kinetic factors on two types of Nakcyguri, one of which uses hip bending and the other uses little it. 12 taekkyoners (males) who are the students of Y University participated in this study. They have been practicing on Taekkyon for five years or more. Positions of CoM, the elapsed time of each phase, ROM of joint and segment angles, ground reaction forces, joint moments of supporting leg were analyzed for this study. The results were as follows; in Nakcyguri with hip bending than without hip bending, anterior/posterior ROM of pelvis, head and swing foot were larger by flexing-extending more, and both vertical and posterior components of GRF were larger during phase 4. It was considered that hip bending produced posterior momentum as well as vertical momentum of trunk during Nakcyguri. In conclusion hip bending was essential and so useful to the successful attack.
Effects of Hoehn-Yahr Scale on the Activation of Lower-Extremity Muscles during Walking with Parkinson's Patients
Kim, Chang-Hwan ; Kim, Mi-Young ; Moon, Je-Heon ; Lim, Bee-Oh ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 287~293
DOI : 10.5103/KJSB.2014.24.3.287
The purpose of this study was to investigate the effects of Hoehn-Yahr scale on the activation of lower-extremity muscles during walking. Electromyography (EMG) analysis was carried out on 36 patients with Parkinson's disease in the off phase of the medication cycle. We recorded EMG signals of the tibialis anterior (TA), medial gastrocnemius (MG), lateral gastrocnemius (LG), soleus (SOL), rectus femoris (RF), vastus lateralis (VL), semitendinosus (ST) and biceps femoris (BF) using Noraxon 16 channels EMG system during walking at preferred speed. Rectified EMG signals were normalized to reference voluntary contractions (RVC) over a gait cycle at the preferred speed, allowing for an assessment of how the activity was distributed over the gait cycle. Compared to the H & Y Scale 1, H & Y Scale 3 exhibited greater activation of the vastus lateralis during mid-stance and greater activation of the medial gastrocnemius during terminal swing. Compared to the H & Y Scale 1, H & Y Scale 2 and 3 exhibited less activation of the tibialis anterior during initial swing. We conclude that the more Hoen & Yahr Scale increase, the more abnormal lower-extremity muscles activation.
Effect of Neuromuscular Training on Postural Control and Jump Performance in Functional Ankle Instability Soccer Player
Yang, Dae-Jung ; Kang, Jeong-Il ; Park, Seung-Kyu ; Lee, Min-Ki ; Jeong, Yong-Sik ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 295~300
DOI : 10.5103/KJSB.2014.24.3.295
The purpose of this study was to investigate the effects on jump performance and balance in soccer player with functional ankle instability of difference of neuromuscular training. In 33 male college soccer player with functional ankle instability subjects of this study randomization, combined training group (group I, n=11), balance training group (group II, n=11) and control group (group III, n=11) that included in the plyometric training and balance training was classified group. The intervention was conducted three times a week for 8 weeks. Before and after intervention, measured in surface area ellipse and countermovement jump and countermovement jump with arm swing. Showed a significant improvement in postural control and jump performance from the combined training group and balance training group compared to the control group. Showed a significant improvement in countermovement jump from the combined training group compared to the balance training group. Combined training and balance training showed the increased jump performance and postural control in soccer player with functional ankle instability.
The Effect of Smartphone Holding Techniques on Kinematic Variables and Muscle Activities in the Thumb during Tapping Numbers
Kim, Dong-Soo ; Chae, Woen-Sik ; Jung, Jae-Hu ; Lee, Haeng-Seob ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 301~308
DOI : 10.5103/KJSB.2014.24.3.301
The purpose of this study was to determine whether there are significant differences in kinematic variables and muscle activities of the thumb between two smartphone holding techniques. Twelve right handed university students(age
, hand length
) who have no musculoskeletal disorder were recruited as the subjects and had experience in using a smartphone for more than one year. Maximum joint angle, angular velocity, muscular activities were determined for each trial. For each dependent variable, paired t-test was used to determine whether there were significant differences between one hand (OH) and two hands ([TH],
<.05). The results of this study showed that there were no significant differences between OH and TH in the maximum joint angle of the thumb. The angular velocity of each joint was not statistically significant between OH and TH. The statistical analysis revealed that the main effect of the smartphone holding conditions was significant in the peak normalized muscular activities of FDI and APL. Although smartphone holding technique doesn't affect on mobility and movement of the thumb joint, it may affect on active degree of the thumb and the upper extremity in directly and indirectly.
Effect of Wrist Resistance Training on Motor Control and Strength in Young Males
Kim, You-Sin ; Kim, Dae-Hoon ;
Korean Journal of Sport Biomechanics, volume 24, issue 3, 2014, Pages 309~315
DOI : 10.5103/KJSB.2014.24.3.309
The aim of the present study was to investigate the effects of 6-week wrist resistance training on wrist torque control. Nineteen subjects were randomly assigned to either the wrist training group (n=9) or the control group (n=10). The training group performed wrist exercises for six directions (flexion, extension, pronation, supination, radial deviation, and ulnar deviation) while the control group did not. Testing for the isometric torque control error, one-repetition maximum (1-RM) strength, and isokinetic maximum torque (angular velocity of
wrist movements) were conducted before and after six weeks of resistance training and after every two-week interval of training. The wrist training group showed significant decreases in isometric torque control error in all six directions after the 2-week resistance training, while the control group did not show significant increase or decrease. The training group showed significant increases in the maximum strength in all six directions assessed by 1-RM strength and isokinetic strength tests after the 4-week resistance training, while the control group did not show any statistically significant changes. This study shows that motor control ability significantly improves within the first two weeks of resistance training, while the wrist strength significantly improves within the first four weeks of resistance training in wrist training group compared to the control.