• 한국운동역학회지
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• 제21권5호
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• pp.529-540
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• 2011

The purpose of this study was to evaluate the kinematic characteristics of $5^{th}$ and $6^{th}$ hurdle clearances during the final of the 110-m hurdles at the IAAF World Championships, Daegu 2011. To this end, the hurdling motions of the top 4 ranked male hurdlers in the competition were analyzed. A total of 12 cameras were used to record their motions, with a sampling frequency of 120 Hz. The cameras were calibrated using $11{\times}2{\times}1\;m$ control objects that covered all of the lanes (1st~8th lanes). After analyzing all the data, we arrived at the following results. In the take-off phase, all athletes revealed similar take-off times (CT), and similar distances from the take-off to hurdleto (L1) and hurdle to landing (L2). In particular, Turner, ranked $3^{rd}$, had an inconsistent L2 and may need further training to correct it. In the flight phase, Richardson, ranked $1^{st}$, showed the longest flight distance, whereas Xiang, who was ranked $2^{nd}$, showed the highest CG height from the hurdle. For the step patterns, to increase the pitch frequency, Richardson and Xiang used shorter 3-step lengths than Turner and Oliver.

• 한국운동역학회지
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• 제21권4호
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• pp.411-420
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• 2011

The purpose of this investigation was to determine whether correlations exist between balance and impact velocity, angular position, and maximum velocity of a club during drive swing. Twelve skilled golfers were recruited in this study. They were asked to perform ten swing trials and two trials were selected for analysis. Balance parameters were calculated via the force platform while kinematic variables were determined by using the Qualisys system. The results of the present study demonstrated that the average of COP velocity was faster in the medio-lateral direction rather than the anterio-posterior direction. Also, left foot's COP velocity and free torque were greater than the right foot's before impact. The range of the right foot's COP in the anterio-posterior direction before impact were correlated with the club velocity and angular position at impact. There was a negative correlation between the left foot's COP velocity before the impact and the velocity at impact. Additionally, the range and RMS of the left foot's free torque affected on the club angular position at impact and the maximum velocity at release, respectively. Finally, a negative correlation existed between the range of the right foot's free torque after the impact and club's maximum velocity at release.

• 한국운동역학회지
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• 제22권2호
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• pp.131-140
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• 2012

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.

• 한국운동역학회지
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• 제26권1호
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• pp.51-69
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• 2016

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.

• 한국운동역학회지
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• 제20권2호
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• pp.129-137
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• 2010

The purpose of this study is to investigate the effect of a 12-week aquatic exercise on obstacle gait in older women. Originally, 20 healthy female elderly participated this study but 12 of them completed the program. All participants were trained in the aquatic exercise program by an authorized trainer. They had come to the authors' lab three times during training period(0, 6, 12 weeks) and performed obstacle gait with three different height(0, 30, and 50% of leg length). After performed 3-Dimensional motion analysis following results were found. (1) For the CV, MVHC, TC, HC, statistically significances were shown in obstacle height. Although significant training effects were not shown, all variables showed typical patterns and it was considered as efficient motion to overcome the height obstacles. (2) The anterior-posterior and vertical GRF of support leg during support phase were revealed in height effect but in training one. However, differences between Peak 1 and Peak 2 in vertical GRF increased as training period increased. (3) Knee and hip resultant joint moments were affected by training but ankle resultant moments remained unchanged.

• 한국운동역학회지
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• 제23권1호
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• pp.11-17
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• 2013

The purpose of this study was to provide a fundamental information for enhancing 110m hurdlers' performance through conducting comparative biomechanical analysis between Skilled Group(SG) and Less-Skilled Group(LSG) those who are not in the first section of 110m hurdles. To persue the purpose of this study, total of 10 hurdlers participated. Then they were divided into two groups; SG: five hurdlers who have won awards with 14-second range at 2010 national track and field event, and LSG: five hudlers who did not win any awards with 15-second range. Three-dimensional motion analysis with 12 infrared cameras(Oqus 300, Qualisys) and 1 force plate(Type 9286AA, Kistler) was performed. From this study following conclusions were obtained. 1) For the overall runtime, SG revealed faster elapsed time than that of LSG. 2) At E4, LSG showed greater trunk angle than that of SG. 3) At E3 LSG revealed higher angular velocities than that of SG. 4) No significant differences was found for AP GRF between groups but LSG showed greater VGRF than that of SG.

• 한국운동역학회지
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• 제20권4호
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• pp.457-467
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• 2010

This study intends to analyze the projection factors' difference on each record of women's javelin throwing. For this purpose, the research analyzed the best record and the lowest one of athletes in top 1~7 ranks respectively, who participated in 2009 Daegu Pre-Championship Meeting. For analyze kinematic factors, we analyzed their game photos mainly shot by 3 cameras installed in side places. The used analysis program was Kwon3D 3.1. Analysis variables were the projection velocity, angle, height, trunk lean angle, and supporting leg's knee angle. The results concluded as follows: Different record showed statistically significant differences(p<.05) in terms of horizontal velocity and resultant velocity. There were no statistically significant differences in the variables of projection angle, its height, trunk lean angle and knee angle of support leg. But for the analyzed results to each individual characteristics, the horizontal velocity, projection height, knee angle of support leg and trunk lean angle of release event appeared to have influence on record.

• 한국운동역학회지
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• 제31권4호
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• pp.270-275
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• 2021

Objective: The purpose of this study was to evaluate 16 muscles activity according to three exercise intensity when performing Deadlift and Upright row. Method: To accomplish the purpose of the study, subjects (n=10) were performed Electromyography (EMG) measurement for 16 different muscles. The experimental movements were Deadlift and Upright row, measured five times for each intensity (40%, 60%, 80%) of 1RM. This study normalized the EMG values through RVC for comparative analysis. Results: The results were summarized as follows: As a result of Deadlift, there was significant difference in the mean EMG value according to the exercise intensity in all muscles except RA, PM and BB (p<.05). As a result of Upright row, There was significant difference in the mean EMG value according to the exercise intensity in all muscles except BF, TA, GN, RA and UT (p<.05). Conclusion: This study allowed us to know the activities of major muscles according to the exercise intensity for 16 different muscles when performing Deadlift and Upright row.

• 한국운동역학회지
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• 제31권1호
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• pp.50-58
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• 2021

Objective: This study aimed to determine the effect of wrist and trunk weight loading using sandbags in stroke patients in order to provide the quantitative data for enhancement of gait movement. Method: Twelve stroke patients, who have been diagnosed with hemiplegia over a year ago, were participated in this study. All subjects were asked to perform normal walking [N], wrist sandbag walking [W], wrist & trunk sandbag walking [WT], and both wrist sandbag walking [B] and both wrist & trunk sandbag walking [BT], respectively. Eight infrared cameras were used to collect the raw data. Gait parameters, arm swing, shoulder-pelvic kinematics, and lower extremity joint angle were calculated to examine the differences during walking. Results: As a result, there were no significant differences in the gait parameters, shoulder-pelvis, and lower extremities joint angles, but significant differences were found in the range of motion and the anteversion in arm swing. Conclusion: Wrist and trunk weight loading using sandbags affected the movement of the upper extremities only while it did not affect the movement of the lower extremities. It implies that it can reduce the risk of falling caused by a sudden movement change in lower extremities. In addition, the wrist and trunk weight loading using sandbags can induce changes in movement of the upper extremities independently and contribute to functional rehabilitation through resistance training.

• 한국운동역학회지
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• 제23권3호
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• pp.261-269
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• 2013

The purpose of this study was to investigate the degree of improvement of scoliosis, muscle function and VAS between the exercise group and the control group after conducting correct posture exercise program with 20 female students diagnosed with scoliosis through PAPS in M middle school for 12 weeks. The conclusion was as follows. Cobb's angle in exercise group was changed from $11.6^{\circ}{\ae}2.5^{\circ}\acute{y} $ to $7.3^{\circ}{\ae}2.0^{\circ}\acute{y} $ which was statistically significant difference (p<.001). However, the change in Cobb's angle was not significant in control group, hence there was no statistically significant difference. The limber back strength was changed from $45.9^{\circ}{\ae}8.7$ kg to $51.6^{\circ}{\ae}14.9$ kg and sit-up was changed from $13.7^{\circ}{\ae}5.1$ times to $12.9^{\circ}{\ae}5.3$ times in exercise group, but they were not statistically significant. Control group also showed no statistically significant change in back strength and sit-up. The degree of VAS was changed from $7.3^{\circ}{\ae}1.6$ to $3.3^{\circ}{\ae}2.4$ which was a statistically significant difference (p<.01) in exercise group. However, there was no statistically significant difference in control group. Consequently, correct posture exercise program was considered to be effective for the reduction of Cobb's angle and degree of VAS for middle school female students with scoliosis. Therefore the correct posture exercise program can be recommended for youth scoliosis to improve and prevent the body imbalance and ultimately for the health of the youths.