Korean Journal of Sport Biomechanics最新文献

{"title":"Kinematic Comparisons of the Tsukahara Vault between a Top-level Athlete and Sublevel Collegiate Athletes","authors":"Cheol-hee Park, Young-Kwan Kim, Chang-Yei Back","doi":"10.5103/KJSB.2016.26.1.71","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.71","url":null,"abstract":"gymnastics between a top-level athlete and sublevel collegiate athletes in order to obtain information on key biomechanical points for successful Tsukahara vaults. Methods: An Olympic gold medalist (height, 160 cm; weight, 52 kg; age, 25 years) and five sublevel collegiate gymnasts (height, 168.2 ± 3.4 cm; weight, 59.6 ± 3.1 kg; age, 23.2 ± 1.6 years) participated in this study. They repeatedly performed Tsukahara vaults including one somersault. Fourteen motion-capturing cameras were used to collect the trajectories of 26 body markers during Tsukahara vaults. Event time, displacement and velocity of the center of mass, joint angles, the distance between the two hands on the horse, and averaged horizontal and vertical impact forces were calculated and compared. Results: The top-level athlete showed a larger range of motion (ROM) of the hip and knee joints compared to sublevel collegiate athletes during board contact. During horse contact, the top-level athlete had a narrow distance between the two hands with extended elbows and shoulders in order to produce a strong blocking force from the horse with a shorter contact time. At the moment of horse take-off, reactive hip extension of the top-level athlete enhanced propulsive take-off velocity and hip posture during post-flight phase. Conclusion: Even though a high velocity of the center of mass is important, the posture and interactive action during horse contact is crucial to post-flight performance and the advanced performance of Tsukahara vaults.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131237037","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Suggestion of New Terminology and Classification of the Hand Techniques by Angular Momentum in the Taekwondo Poomsae","authors":"Sihyun Yoo, Kuk Hyun Jung, Jiseon Ryu","doi":"10.5103/KJSB.2016.26.1.51","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.51","url":null,"abstract":"Objective: The purpose of this study is to suggest new terminology for the ninety-five hand techniques based on the significance of their angular momentum, determined by analyzing each technique``s influence or impact on the compartmentalized angular momentum of the trunk, upper arm, and forearm in the Taekwondo Poomsae. Method: An athlete who won the 2014 World Taekwondo Poomsae championship was selected and agreed to participate in the data collection phase of our investigation. The video data was collected using eight infrared cameras (Oqus 300, Qualysis, Sweden) and the Qualisys Track Manager software (Qualisys, Sweden). The angular momentum of each movement was then calculated using the Matlab R2009a software (The Mathworks, Inc., USA). Results: The classification of the ninety-five hand techniques in the Taekwondo Poomsae based on the significance of each segment``s momentum is as follows. Makgi (blocking) is classified into fourteen categories, jireugi (punching) is classified into three categories, chigi (hitting) was classified into six categories, palgupchigi (elbow hitting) was classified into four categories, and jjireugi (thrusting) was classified two categories. Conclusion: This study offers a new approach, based on a biomechanical method, to the classification of the hand techniques that reflect kinesthetic motions in the Taekwondo Poomsae.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"60 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126850000","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Biomechanical Characteristics of Rowing Performance between Elite and Non-Elite Scull Rowers: A Pilot Study","authors":"Jin Sun Kim, Han-Yeop Cho, Boram Han, S. Yoon, Seonhyung Park, Hyun-Seung Cho, Joo-Hyeon Lee, Hae-Dong Lee","doi":"10.5103/KJSB.2016.26.1.21","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.21","url":null,"abstract":"Objective: This study aimed to examine the characteristics of joint kinematics and synchronicity of rowing motion between elite and non-elite rowers. Methods: Two elite and two non-elite rowers performed rowing strokes (3 trials, 20 strokes in each trial) at three different stroke rates (20, 30, 40 stroke/min) on two stationary rowing ergometers. The rowing motions of the rowers were captured using a 3-dimensional motion analysis system (8-infrared camera VICON system, Oxford, UK). The range of motion (RoM) of the knee, hip, and elbow joints on the sagittal plane, the lead time (TLead) and the drive time TDrive) for each joint, and the elapsed time for the knee joint to maintain a fully extended position (TKnee) during the stroke were analyzed and compared between elite and non-elite rowers. Synchronicity of the rowing motion within and between groups was examined using coefficients of variation (CV) of the TDrive for each joint. Results: Regardless of the stroke rate, the RoM of all joints were greater for the elite than for non-elite rowers, except for the RoMs of the knee joint at 30 stroke/min and the elbow joint at 40 stroke/min (p < .05). Although the TLead at all stroke rates were the same between the groups, the TDrive for each joint was shorter for the elite than for the nonelite rowers. During the drive phase, elite rowers kept the fully extended knee joint angle longer than the non-elite rowers (p < .05). The CV values of the TDrive within each group were smaller for the elite compared with non-elite rowers, except for the CV values of the hip at all stroke/min and elbow at 40 stroke/min. Conclusion: The elite, compared with non-elite, rowers seem to be able to perform more powerful and efficient rowing strokes with large RoM and a short TDrive with the same TLead.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131611070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effect of Frequency of Transcutaneous Electrical Nerve Stimulation (TENS) on Maximum Multi-finger Force Production","authors":"Sohit Karol, K. Koh, H. Kwon, Y. Park, Y. Kwon, J. Shim","doi":"10.5103/KJSB.2016.26.1.93","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.93","url":null,"abstract":"Department of Kinesiology, University of Maryland, College Park, MD, USA Department of Mechanical Engineering, Kyung Hee University, Yong-in, South Korea Department of Physical Education, Hanyang University, Seoul, South Korea The Movement Science Center of Research Institute for Sports Science and Sports Industry, Hanyang University, Seoul, Korea Fischell Department of Bioengineering/ Neuroscience and Cognitive Science (NACS) Program, University of Maryland, College Park, MD, USA","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"138 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124335680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Biomechanical Differences based on Distance Changes in Connection with Approach Swings of Tour-professional Golfers","authors":"M. You, Kyung-Ill Lee","doi":"10.5103/KJSB.2016.26.1.83","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.83","url":null,"abstract":"Objective: This study aimed to compare differences in biomechanical factors according to distance changes in relation to approaches during a round of golf to obtain basic data on golf swings. Methods: The research subjects were 8 KPGA-affiliated professional golfers who performed approach shots that put a ball into a circle of 8 feet in diameter from distances of 30, 50, and 70 m. Data were collected by using six infrared cameras and a ground reaction force device, which were applied to calculate biomechanical factors by using Kwon3D XP. The calculated data were subjected to one-way ANOVA by using SPSS 20.0, with the significance level set at p value of 0.05. Results: Elapsed time, stance width, clubhead position variation, clubhead synthesis speed, and cocking angle significantly differed according to distance change during the approach swing. Clubhead speed was positively related with stance width and clubhead displacement. Ground reaction force significantly differed according to distance change during the approach swing. Factors before and after showed differences in other states, except in the impact state. Conclusion: In the present study, we drew several conclusions regarding biomechanical factors and ground reaction forces according to distance change in the approach swing of professional golfers. According to these conclusions, we suggest that distance control with swing range is more important than power control in maintaining the accuracy and consistency of golf swing and is the most important mechanism of golf swing.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123223006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation Analysis between Dance Experience and Smoothness of Dance Movement by Using Three Jerk-Based Quantitative Methods","authors":"Y. Park","doi":"10.5103/KJSB.2016.26.1.1","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.1","url":null,"abstract":"The jerk-based quantitative method was first introduced for explaining the process and prediction of hand movement in space early on, and it was based on the principle that the maximum smoothness theory could be predicted by a bell-shaped velocity curve and straight line trajectory, which were the scales for assessing dynamic optimization by using kinematic end-point trajectory (Flash & Hogan, 1985). The jerk theory involved a method for calculating the jerk cost at the early stage. The jerk cost was calculated by differentiating the position coordinates during motor performance three times with respect to time (Schneider & Zernicke, 1989). Many researchers in the field of kinematics discovered through the jerk theory that a skilled individual moved his or her arms as smoothly as possible, which was based on the minimum-jerk hypothesis that states that the intensity of jerk decreased in more skilled motor performance. Moreover, the smoothness was quantitatively measured by integrated squared jerk (Platz, Denzler, Kaden, & Mauritz, 1994). In other words, from a kinematic perspective, this represented a concept that the integral KJSB Korean Journal of Sport Biomechanics 2016; 26(1): 1-9 http://dx.doi.org/10.5103/KJSB.2016.26.1.1 http://e-kjsb.org eISSN 2093-9752 ORIGINAL","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"440 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134268737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Kinematic Comparisons of Kettlebell Two-Arm Swings by Skill Level","authors":"Chang-Yei Back, Ji-yong Joo, Y. K. Kim","doi":"10.5103/KJSB.2016.26.1.39","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.39","url":null,"abstract":"Objective: The purposes of this study were to compare the kinematics of a two-arm kettlebell swing between experts and beginners and to identify the correct postures and biomechanical key points in an attempt to prevent sports injuries induced by a kettlebell swing. Methods: Four experts (height, 169.7 ± 1.5 cm; weight, 70.5 ± 1.8 kg; age, 32.0 ± 1.0 years) licensed to teach kettlebell exercises and three beginners (height, 173.7 ± 4.1 cm; weight, 78.3 ± 3.8 kg; age, 30.0 ± 1.4 years) with no kettlebell exercise experience participated in this study. Each participant performed 15 repetitions of a two-arm kettlebell swing using a 16-kg weight. Joint angles, angular velocities, and peak angular velocity sequences were calculated and compared between the two groups. Results: Large ranges of motion (ROM) of the pelvic angle and hip joints were detected in the experts, while beginners showed greater ROM of the shoulder joint. Peak angular velocity magnitudes and sequences were significantly different between the two groups. Experts lifted the kettlebell upward using the hip joints, pelvis, and shoulder joints (proximal to distal order) sequentially and lowered it using the reverse order of peak angular velocities from the shoulder to hip joints. Conclusion: Mobility of the pelvic segment and hip joint are required, while stability of the other joints is needed to produce appropriate two-arm kettlebell swings. The activation and coordination of the gluteal and hamstring muscles are key points in kettlebell exercises.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"63 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117333202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Biomechanical Characteristics for the Skill Level in Cycle Pedaling","authors":"G. Lee, J. Kim, Sung-Sun Kang, A. Hong, Jaemoo So","doi":"10.5103/KJSB.2016.26.1.11","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.11","url":null,"abstract":"Objective: This study aimed to compare biomechanical data between elite and beginner cyclists during cycle pedaling by performing a comparative analysis and to provide quantitative data for both pedaling performance enhancement and injury prevention. Methods: The subjects of this study included 5 elite cyclists (age: 18 ± 0 years, body mass: 64.8 ± 9.52 kg, height: 173.0 ± 4.80 cm) and 5 amateur cyclists (age: 20 ± 0 years, mass: 66.6 ± 2.36 kg, height: 175.6 ± 1.95 cm). The subjects pedaled on a stationary bicycle mounted on rollers of the same gear (front: 50 T and rear: 17 T = 2.94) and cadence of 90. The saddle height was adjusted to fit the body of each subject, and all the subjects wore shoes with cleats. In order to obtain kinematic data, 4 cameras (GR-HD1KR, JVC, Japan) were installed and set at 60 frames/sec. An electromyography (EMG) system (Telemyo 2400T, Noraxon, USA) was used to measure muscle activation. Eight sets of data from both the left and right lower extremities were obtained from 4 muscles (vastus medialis oblique [VMO], vastus lateralis oblique [VLO], and semitendinosus [Semitend], and lateral gastrocnemius [Gastro]) bilaterally by using a sampling frequency of 1,500 Hz. Five sets of events (0°, 90°, 180°, 270°, and 360°) and 4 phases (P1, P2, P3, and P4) were set up for the data analysis. Imaging data were analyzed for kinematic factors by using the Kwon3D XP computer software (Visol, Korea). MyoResearch XP Master Edition (Noraxon) was used for filtering and processing EMG signals. Results: The angular velocity at 360° from the feet was higher in the amateur cyclists, but accelerations at 90° and 180° were higher in the elite cyclists. The amateur cyclists had greater joint angles at 270° from the ankle and wider knee joint distance at 0°, 180°, and 360° than the elite cyclists. The EMG measurements showed significant differences between P2 and P4 from both the right VLO and Semitend. Conclusion: This study showed that lower body movements appeared to be different according to the level of cycle pedaling experience. This finding may be used to improve pedaling performance and prevent injuries among cyclists.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127376951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Immediate Effects of External Kinesio-tape Wrapping for Inner Arch Support on the Lower Leg EMG for Gait in Stiletto Heels","authors":"Kyungock Yi","doi":"10.5103/KJSB.2016.26.1.127","DOIUrl":"https://doi.org/10.5103/KJSB.2016.26.1.127","url":null,"abstract":"Purpose: The purpose of this study was to analyze the effects of using external kinesiotape wrapping for inner arch support on the lower extremity EMG for gait in stiletto heels. Methods: Subjects for this study were two female college students who had been wearing stiletto heels almost every day of the week for more than three years. The independent variable was the presence or absence of kinesio-tape wrap for inner arch support. Dependent variables were EMG readings for the four muscle groups: the medial and lateral gastrocnemius, the tibialis anterior, and the peroneus longus. EMG readings were taken using the NORAXON (USA). The Paired t-test within the subject repeated measure design for the presence and absence of inner arch support (p<0.05) was used via SPSS 18.0. Results: With kinesio-tape wrap for inner arch support, there was a statistically significant decrease in the muscle force mean values for the peroneus longus and the medial and lateral gastrocnemius, in the maximum muscle forces of the peroneus longus and the lateral gastrocnemius. Conclusion: External kinesio-tape wrapping for inner arch support in stiletto heels could have an effect to reduce peroneus longus, and medial/lateral gastrocnemius activities that could result in decreased fatigue and discomfort.","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116982459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"파킨슨 환자들의 질환등급, 균형, 낙상 및 보행능력 평가척도 고찰","authors":"김창환, 김미영, 임비오","doi":"10.5103/KJSB.2015.25.4.441","DOIUrl":"https://doi.org/10.5103/KJSB.2015.25.4.441","url":null,"abstract":"Objective : The purpose of the study was to investigate and compare the differences between Parkinson``s disease rating, balance, fall and gait scales. Results : Parkinson``s disease rating scales include the Hoehn-Yahr Scale and the Unified Parkinson``s Disease Rating Scale (UPDRS). The Hoehn-Yahr Scale can measure disease rates easily; however it is not sensitive enough to evaluate the disease’s process and management. UPDRS’s advantage is in it’s higher inter-reliability score; however it is more complicated to use. Parkinson``s balance scales are comprised of the Berg Balance Scale (BBS) and the Activities-Specific Balance Confidence Scale (ABC). BBS has the advantage in that it is cheaper to measure and simple in use. ABC’s advantage is especially in it’s ability to measure higher functional levels; however it is more difficult measure responses due to scores appearing in both extremes. The Fall Efficacy Scale (FES) and The Survey of Activities and Fear of Falling in the Elderly (SAFE) are Parkinson``s fall scales. FES’s leverage over SAFE is that it is simpler to measure; however it does not coincide with responses which proves disadvantageous in measuring balance loss in high-level Parkinson``s patients. SAFE’s advantage is in it’s simpler use and ability to be utilized without encountering the fear of fall; however it’s at a disadvantage in regards to its use with multilateral aspects providing insufficient inspection. Lastly, the Dynamic Gait Index (DGI) and the Functional Gait Assessment (FGA) are Parkinson``s gait scales. DGI is advantageous in its ability to test gait ability when exposed to a variety of external environments; however it is disadvantageous in that it registers higher scores with activities. FGA’s advantage is in it’s dynamic balance test; however it at a disadvantage with those unable to walk. Conclusion : A researcher of Parkinson``s patients must choose each scale while considering their positive and negative characteristics","PeriodicalId":306685,"journal":{"name":"Korean Journal of Sport Biomechanics","volume":"454 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116062075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}