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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Korean Journal of Sport Biomechanics
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Journal DOI :
Korean Society of Sport Biomechanics
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Volume & Issues
Volume 21, Issue 5 - Dec 2011
Volume 21, Issue 4 - Dec 2011
Volume 21, Issue 3 - Sep 2011
Volume 21, Issue 2 - Jun 2011
Volume 21, Issue 1 - Mar 2011
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Change in Kinetics and Kinematics during 1-Footed Drop Landing with an Increase in Upper Body Weight
Lee, Jin-Taek ; David, O'Sullivan ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 1~7
DOI : 10.5103/KJSB.2011.21.1.001
The purpose of this study was to investigate changes in kinetic and kinematic variables associated with an increase in upper body weight. Eighteen healthy male university students(
) participated. Eight motion analysis cameras(Qualysis Oqus 500) and 2 force AMTI platforms(Advanced Mechanical Technologies Inc. OR6-7, US) were used to record motion and forces during the drop landing at a frequency of 120 Hz and 1200 Hz, respectively. QTM software(Qualisys Track Manager) was used to record the data, and the variables were analyzed with Visual 3D and Matlab 2009. For the drop landing, a box of
was constructed from wood. Knee and ankle maximum flexion angle, knee flexion angle, knee and ankle angle at landing, time for maximum ankle flexion after landing, and time for maximum knee flexion after landing were calculated. There was a significant change in the time for maximum and minimum ground force reaction and the time for maximum dorsal flexion after landing(p<.05) with increasing weight. There was no significant change for the hip, knee, and ankle ROM, whereas there was an increase in the angle ROM as the weight increased, in the order of ankle, knee, and hip ROM. This result shows that the ankle joint ROM increased with increasing weight for shock attenuation during the drop landing. There was a trend for greater ankle ROM than knee ROM, but there was no clear change in the ROM of the hip joint with increasing weight. In conclusion, this study shows the importance of ankle joint flexibility and strength for safe drop landing.
The Effects of Shoe Type on Ground Reaction Force
Yi, Kyung-Ok ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 9~16
DOI : 10.5103/KJSB.2011.21.1.009
The purpose of this study is to analyze the effects of both various shoe types and bare feet on ground reaction force while walking. Ten first-year female university students were selected. A force platform(Kistler, Germany) was used to measure ground reaction force. Six types of shoe were tested: flip flops, canvas shoes, running shoes, elevated forefoot walking shoes, elevated midfoot walking shoes, and five-toed shoes. The control group was barefooted. Only vertical passive/active ground reaction force variables were analyzed. The statistical analysis was carried out using the SAS 9.1.2 package, specifically ANOVA, and Tukey for the post hoc. The five-toed shoe had the highest maximum passive force value; while the running shoe had the lowest. The first active loading rate for running shoes was the highest; meanwhile, bare feet, the five-toed shoe, and the elevated fore foot walking shoe was the lowest. Although barefoot movement or movement in five toed shoes increases impact, it also allows for full movement of the foot. This in turn allows the foot arch to work properly, fully flexing along three arches(transverse, lateral, medial), facilitating braking force and initiating forward movement as the tendons, ligaments, and muscles of the arch flex back into shape. In contrast movement in padded shoes have a tendency to pound their feet into the ground. This pounding action can result in greater foot instability, which would account for the higher loading rates for the first active peak for padded shoes.
Trend Analysis of Exercise Content on the Rings Final in the 1st Youth Olympic Games
Han, Yoon-Soo ; Kwon, Oh-Seok ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 17~24
DOI : 10.5103/KJSB.2011.21.1.017
The Youth Olympic Games(YOG) is an international multi-sport event first held in Singapore from August 14 to August 26, 2010. The idea for such an event was introduced by International Olympic Committee(IOC). The Federation of International Gymnastics(2009) designed the Code of Points and regulates for junior gymnastics at this time. The purpose of this study was to give crucial information and adapt to coaches and junior gymnasts at the time of changing code rapidly. For this study, The eight finalists rings exercise at the 1st Youth Olympic Games was recorded using a digital camcoder. The exercise contents analysis of rings was carried out by an experienced international judge using Code of Points(FIG, 2009). The C elements in various difficulties were performed the highest frequency. The elements group I was the most frequently performed in overall difficulties. Moreover, All the gymnasts performed the elements of the Jonasson and Yamawaki in Group I. Therefore, junior gymnasts need to consider Jonasson and Yamawaki elements correctly in elements group I. The 1st ranked ROU(132) gymnast performed high difficulty value for his routine with the highest E score(9.050). The average of D score were 5.125. In the E scores, 8th USA(140) gymnast received the lowest E score of 8.15, 5th MGL(127) gymnasts received the fewer E score of 8.475. Coaches and junior gymnasts should try to increase D score above 5.125 by higher swing elements in Group I and II as well, decrease deduction of elements in exercise contents.
Quantitative and Qualitative Differences according to the Shoe Type for the Grand Jete Landing in Ballet
Yi, Kyung-Ok ; Park, Hye-Rhee ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 25~29
DOI : 10.5103/KJSB.2011.21.1.025
The purpose of this study was to analyze quantitative and qualitative differences according to shoe type for the grand jete landing in ballet. The subjects for this study were 9 female ballet majors with an average of 12 years of experience. Subjects jumped, performing a front split, and landed on 1 foot, a movement called the grand jete. Analysis was performed on the students' landing. Independent variables were 3 shoe types: split sole, traditional out sole, and 5-toed forefoot shoes, with bare feet as a control group. Dependent variables were vertical passive ground reaction force and qualitative elements. Passive ground reaction force variables(maximum passive peak value, number of passive peaks, passive force-time integral, and center of pressure) were measured by the Kistler 9281B Force Platform. Qualitative elements were comfort, cushioning, pain, and fit. Statistical analysis included both 1-way ANOVA and Tukey's test for follow-up. Finalized data demonstrated that the 5-toed forefoot shoe allows the forefoot to expand and the toes to individually press down upon landing, increasing foot contact with the surface. Five-toed forefoot shoes minimize passive peaks and pain, while increasing comfort, cushioning, and fit. Most ballet movements are composed of jumping, balancing, landing, and spinning. Wearing 5-toed forefoot shoes allows for a natural range of movement in each toe, to improve both technique and balance. Pain and injuries from ballet can be minimized by wearing the correct shoe type. According to this analysis, it is possible to customized ballet shoes to increase the efficiency of techniques and movements.
Effects of Visual Information Blockage on Landing Strategy during Drop Landing
Koh, Young-Chul ; Cho, Joon-Haeng ; Moon, Gon-Sung ; Lee, Hae-Dong ; Lee, Sung-Cheol ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 31~38
DOI : 10.5103/KJSB.2011.21.1.031
This study aimed to determine the effects of the blockage of visual feedback on joint dynamics of the lower extremity. Fifteen healthy male subjects(age:
) participated in this study. Each subject performed single-legged landing from a 45 cm-platform with the eyes open or closed. During the landing performance, three-dimensional kinematics of the lower extremity and ground reaction force(GRF) were recorded using a 8 infrared camera motion analysis system (Vicon MX-F20, Oxford Metric Ltd, Oxford, UK) with a force platform(ORG-6, AMTI, Watertown, MA). The results showed that at 50 ms prior to foot contact and at the time of foot contact, ankle plantar-flexion angle was smaller(p<.05) but the knee joint valgus and the hip flexion angles were greater with the eyes closed as compared to with the eyes open(p<.05). An increase in anterior GRF was observed during single-legged landing with the eyes closed as compared to with the eyes open(p<.05). Time to peak GRF in the medial, vertical and posterior directions occurred significantly earlier when the eyes were closed as compared to when the eyes were open(p<.05). Landing with the eyes closed resulted in a higher peak vertical loading rate(p<.05). In addition, the shock-absorbing power decreased at the ankle joint(p<.05) but increased at the hip joints when landing with the eyes closed(p<.05). When the eyes were closed, landing could be characterized by a less plantarflexed ankle joint and more flexed hip joint, with a faster time to peak GRF. These results imply that subjects are able to adapt the control of landing to different feedback conditions. Therefore, we suggest that training programs be introduced to reduce these injury risk factors.
Change in Rotational Motion of the Shoulder and Hip According to the Method Used for a 2-Handed Backhand Stroke in Tennis
Kang, Sang-Hack ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 39~46
DOI : 10.5103/KJSB.2011.21.1.039
The purpose of this study was to examine differences between players who bend the left elbow and those who stretch it during the forward swing from BST to BC in a 2-handed backhand stroke among outstanding high school tennis players, and to assess the detailed 3D rotational kinematic characteristics of the shoulder and the hip. Statistically significant differences were observed between groups in the longitudinal axis rotation angle of the shoulder and the angle between the shoulder and the arm at BST, and in the side to side movement of the shoulder, the up and down movement of the hip, the side tilt angular velocity of the shoulder, the side tilt angular velocity of the hip, and the front tilt angular velocity of the hip at BC. The difference in the longitudinal axis rotation angle of the shoulder between the 2 groups suggests a difference in the flexibility of the joint in the shoulder arm racquet system. The longitudinal axis rotation angular velocity of the shoulder reached its peak at 75 % of the duration of the analyzed segment and then decreased little by little until BC. This time is considered the stage for increasing the angular velocity of the upper arm, the forearm, the hand and then the racquet, which are more distal segments than the shoulder.
A Kinematic Analysis of Harai-Goshi(Hip Throw) in Judo
Kim, Kab-Sun ; Park, Chuel-Hong ; Lee, El-Koo ; Chung, Nam-Ju ; Kim, Dong-Hyeon ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 47~55
DOI : 10.5103/KJSB.2011.21.1.047
The purpose of this study was to perform a kinematic analysis of Harai-goshi(hip throw) in superior female judo players. From our analysis, it appeared desirable for the player to shorten the duration of the technique for maximum results. It was also desirable for the player to draw the opponent backward while simultaneously maneuvering her close to her own body. A turning movement of the body toward the left side was found to be required for the technique, during which the player must lower the position of the center of gravity. During the subsequent angular change of the elbow, the player winds the elbow and, by moving the left shoulder, pulls the opponent toward her. The player lowers the body center by bending the left knee and letting the right knee extend, while turning the upper body and bending the hip joint. The player then draws the opponent in, contacts the opponent closely, turns, and stretches the right knee and hip joint rapidly and concisely, completing the move; it was also found to be desirable for the angular velocity to be increased for maximum efficacy.
Biomechanical Analysis of the Tippelt Motion on the Parallel Bars
Kim, Min-Soo ; Back, Jin-Ho ; Back, Hun-Sig ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 57~65
DOI : 10.5103/KJSB.2011.21.1.057
This research was conducted to biomechanically analyze Tippelt motion in parallel bars, and establish technical understanding. To achieve that goal, the performances of the Tippelt acts carried out by five world top-class national gymnasts in the parallel bars 3-dimensional cinematographic analysis and EMG analysis were conducted and following conclusion were obtained. The Tippelt motions of excellent national gymnasts perform tap motion through the down swing of a large circular movements, and perform kick-out motion rapidly extending shoulder joint angle and hip joint angle with the trunk in a position close to perpendicular position at the vertical downwardness of the grasping the bars. At this time, if handstand starting the movement is too delayed or rapidly down swung, it was shown that from the initial falling, unnecessary muscular power was wasted in trapezius, anterior deltoid, erector spinae, latissimus dorsi, upper rectus abdominis, lower rectus abdominis. The muscular parts in tap motion generating muscle action potential were pectoralis major, rectus femoris, upper rectus abdominis, lower rectus abdominis, and those in kick-out motion were upper rectus abdominis, lower rectus abdominis, trapezius and anterior deltoid.
Comparative Analysis on Gait Patterns of the Elderly and the Young Regarding to Foot Pressure
Lee, Kyung-Deuk ; Kim, Dae-Woong ; Yoo, Jung-Hyeon ; Kim, Kyung-Hun ; Lee, Tae-Yong ; Park, Kwang-Suk ; Chung, Gih-Sung ; Park, Seung-Bum ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 67~75
DOI : 10.5103/KJSB.2011.21.1.067
The purpose of this study was to find the difference in gait patterns when elderly and young people walk by analyzing COP, Gait Line, Foot pressure pattern, and ensuring the original biomechanics technology of developing high performance footwear for the elderly. The subjects who took part in the test consist of 20 elderly people and 20 young people. The physical features of the elderly people that were recruited for the study are as below: 20 healthy male subjects(elderly people) with an average age of 75.43 yrs(S.D 6.46 yrs), weight of 68.10 kg(S.D 0.94 kg) and a height of 168.65 cm(S.D 1.47 cm). Foot pressure pattern data was collected using a EMED-AT system(Novel Gmbh, Germany) operating at the 50 Hz during walking. The results are as follow : COP route of the elderly leans to lateral compared to the young, and Gait Line from heel to toe is not clear and laterally curved. At the same time, a contact are aonthe midfoot is high compared to the young, and maximum force of the forefoot is low. As a result of analysis, in order to develop high performance footwear for the elderly, it is necessary to develop lasts and soles reflecting the elderly's gait patterns.
Kinematic Analyses of Scapula Depression in Cucarachas Movements in Dance Sport Rumba
Lee, Jin ; Oh, Cheong-Hwan ; Huh, Eun-Hye ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 77~83
DOI : 10.5103/KJSB.2011.21.1.077
In dance sport, hip movement is the most basic and essential technique, connecting the body movements to make the body move organically, and providing an overall balance of body movements. From that perspective, this study focused on the Cucarachas movement, representing a series of efficient hip movements in the center of gravity. For the purposes of this study, 4 dance sport participants who had won prizes at international contests were selected in order to analyze such variables as the radius of gyration (shift) on the hips and the shift of the center of gravity when scapula depression was performed and when it was not. To examine differences in these kinematic variables, a paired t-test was conducted, resulting in the following findings: First, the dancers were found to be able to control scapula depression, and a significant difference was observed in the vertical axis(Z) between the times when scapula depression was performed and when it was not. Second, when scapula depression was performed, shifts in the left-right axis(X) and anterior-posterior axis(Y) were found; the left-right axis showed a greater difference than the anterior-posterior axis. Third, scapula depression was found to have an influence on the shift to the left-right axis(X) of the center of gravity.
The Development of A Basic Golf Swing Analysis Algorithm using a Motion Analysis System
Seo, Jae-Moon ; Lee, Hae-Dong ; Lee, Sung-Cheol ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 85~95
DOI : 10.5103/KJSB.2011.21.1.085
Three-dimensional(3D) motion analysis is a useful tool for analyzing sports performance. During the last few decades, advances in motion analysis equipment have enabled us to perform more and more complicated biomechanical analyses. Nevertheless, considering the complexity of biomechanical models and the amount of data recorded from the motion analysis system, subsequent processing of these data is required for event-specific motion analysis. The purpose of this study was to develop a basic golf swing analysis algorithm using a state-of-the-art VICON motion analysis system. The algorithm was developed to facilitate golf swing analysis, with special emphasis on 3D motion analysis and high-speed motion capture, which are not easily available from typical video camera systems. Furthermore, the developed algorithm generates golf swing-specific kinematic and kinetic variables that can easily be used by golfers and coaches who do not have advanced biomechanical knowledge. We provide a basic algorithm to convert massive and complicated VICON data to common golf swing-related variables. Future development is necessary for more practical and efficient golf swing analysis.
Analysis of Impulse Force and Kinematic Factors of the Limbs during Stefan Holm's Take-off Phase and Penultimate Stride of High Jump
Lee, Jin-Taek ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 97~105
DOI : 10.5103/KJSB.2011.21.1.097
The purpose of this study was to investigate the kinetic factors of Stefan holm's take-off motion and provide the technical data. Collected data of the subject(height: 181 cm, weight: 71 kg, record: 230 cm) were used for the last two strides and take-off phase. The results were as follows: The vertical impulse force was 2044.8 N which was 2.49 times and the anterior-posterior impulse force was -1306.4 N which was 1.88 times of the subject's weight. The take-off leg angular velocities(
) were switched drastically from clockwise to count clockwise direction between two-step touchdown and take-off. The highest jerk of the take-off foot was 368.97 m/s3 during the two step take-off and the take-off foot made an impact to the ground with 1225.07 m/s3 during the one step touchdown.
Analysis of Patellar Tracking and Q-angle During Semi-Squat Exercises
Park, Seung-Kyu ; Yang, Dae-Jung ; Park, Jae-Man ; Han, Song-E ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 107~114
DOI : 10.5103/KJSB.2011.21.1.107
Closed kinematic chain exercises such as squatting have been widely indicated for knee rehabilitation in patients with patellofemoral disorders such as osteoarthritis and patellofemoral pain. Patellofemoral disorders are thought to be associated with abnormal patellar kinematics. In addition, the Q-angle may be undervalued in patients with patellofemoral pain and a laterally displaced patella. The purpose of this study was to assess patellar kinematics and the Q-angle during double-leg semi-squat and wall-slide semi-squat exercises. In this study, 28 asymptomatic subjects(16 male, 12 female) were assessed. Patellar tilt, patellar spin, and Q-angle were recorded using a motion analysis system during double-leg semi-squat and wall-slide semi-squat exercises. The Q-angle and patellar tilt were significantly increased, whereas patellar spin was significantly decreased, at
of knee flexion compared with
. No differences were observed for the Q-angle, patellar tilt, and patellar spin during double-leg semi-squat and wall-slide semi-squat exercises. However, a significant interaction was observed between squat type and knee angle for patellar spin. We found that the patella is laterally tilted during semi-squat exercises and that there was no difference in patellar tracking between knee flexion during double-leg semi-squat and wall-slide semi-squat exercises.
Effects of Muscle Fatigue through Maximum Contraction during Flexion and Extension of Knee Before and After Isometric Trunk Exercise on Elderly Hansen's Disease
Jung, Soon-Mi ;
Korean Journal of Sport Biomechanics, volume 21, issue 1, 2011, Pages 115~121
DOI : 10.5103/KJSB.2011.21.1.115
This study was to investigate the change of muscle fatigue through maximum contraction during flexion and extension of knee joint before and after the isometric trunk exercise was implemented on elderly Hansen's disease. 18 subjects exercised for 60 minutes twice a week for 12 weeks. The subjects were divided into normal sensory group, group with sensory loss in left sole, group with sensory loss in right sole, and group with sensory loss in both soles, according to the sensory condition on their soles. We obtained following results. Muscle fatigue in normal sensory group, there were significant differences in left right hamstring, left rectus femoris(p<.05), in group with sensory loss in left sole, there were significant differences in left right hamstring(p<.05), in group with sensory loss in right sole, there were significant differences in left right hamstring, right rectus femoris and group with sensory loss in both sole, there were significant differences in right hamstring(p<.05). The differences of muscle fatigue according to the sensory condition on their soles, there were significant differences in left hamstring between normal sensory group and group with sensory loss in both sole(p<.05).