• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.149-152
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• 1999

Computer-Aided Engineering (CAE) is one of the most effective method in design of golf clubs for determination of optimum shapes in short lead time. A new design of golf club drive with gas-filled titanium head has been carried out using two FEM softwares MARC and DYNA-3D. The main research work focuses on the decision of face thickness and the effect of filled gas pressure by analyzing the change of the kinematic energy of the ball during impact.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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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.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.71-78
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• 2005

The purpose of this research was to conduct an analysis on the factors that determine the distance at the time of target swing based on the use of late hitting of outstanding college golfers to verify the difference between late hitting and the distance that target increases in regular swing and the distance. Then, this research conducts an analysis on the correlation between club head velocity, ball velocity, launch angle, back spin, meet ratio and distance that become kinematics variables at the time of target swing. To attain the above mentioned purpose, 25 outstanding college players with average experience and handicap of 6 years and 5, respectively, were targeted Comparative analysis on two swing that target increase in regular and the distance was conducted by used driver. When it pertained to two types of swing. analysis system comprised of an analytical software called the Science Eye of the Bridgestone and peripheries was used to define the relationship between variables of club head velocity, ball velocity, launch angle, back spin, meet ratio that become kinematics variables. As for the method of processing data pertaining to the factors that determine the distance, differences of distance by the type of swing was verified by using independent T-test that leveraged SPSS 120 statistics program. Moreover, level of correlation between variables that contribute to the increase in distance through relation of correlation, and analysis of tendencies was conducted to analyze tendency of non-distance to increase in accordance to the increase of each variable. Key results produced through this experiment are as follows: 1. Artificial late hitting for increased non-distance that targets skilled players had effect on increased the distance(p<. 05). 2 The drive distance is correlated with each measured variable that is positive correlation to ball velocity, club head velocity, meet ratio and relation of back spin and launch angle are negative correlation. ball velocity and club head velocity are very high correlated with drive distance(p<.01), back spin and distance are negative correlation(p<.01). 3. Among each measured variable increasing the club velocity is the most contribution, and ball velocity and meet ratio and the increasing launch angle and back spin is negative effect for increasing distance.

• The Research Journal of the Costume Culture
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• v.22 no.4
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• pp.632-639
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• 2014

The purpose of this study was to verify the effect of drive swing on multiple functional wear wearing in golf. The subjects were 6 men ($22.67{\pm}0.82$ yrs, $175.42{\pm}3.42cm$, $78.75{\pm}4.78kg$), who had career each with at least 8 yers golf experience with right-hander. For kinemetical analysis, this study used equipments with 7 motion capture cameras (300Hz) and analysis program (Nexus1.5). The total time of the club head, displacement magnitude of the COM and swing plane were compared of according to functional wear wearing and non-weraing during golf drive swing. The results of the study are as follows. The total time of the club on wearing ($2.18{\pm}0.06sec$) was faster than non-wearing ($2.52{\pm}0.15sec$). Displacement magnitude of the COM on wearing ($4.06{\pm}0.67cm$) was shorter than non-wearing ($5.79{\pm}0.72cm$). Also, swing plane was found to be significantly different of 3 phase excepted BST-DS (back swing top-down swing) phase. AD-BST (address-back swing top) phase on wearing ($13.86{\pm}3.08cm$) decrease more than non-wearing ($20.82{\pm}3.99cm$), DS-IP (down swing-impact) phase on wearing ($6.25{\pm}1.35cm$) decrease more than non-wearing ($7.18{\pm}1.52cm$) and IP-FT (impact-follow though) phase on wearing ($7.93{\pm}2.09cm$) decrease more than non-wearing($9.68{\pm}2.02cm$). The multiple functional wear wearing was contribution to come close for one-plane, a long with consistency and accuracy on golf drive swing.

• Journal of Power Electronics
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• v.14 no.1
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• pp.74-81
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• 2014

In this study, a brain emotional learning-based intelligent controller (BELBIC) is developed for the speed control of an interior permanent magnet synchronous motor (IPMSM). A novel and simple model of the IPMSM drive structure is established with the intelligent control system, which controls motor speed accurately without the use of any conventional PI controllers and is independent of motor parameters. This study is conducted in both real time and simulation with a new control plant for a laboratory 3 ph, 3.8 Nm IPMSM digital signal processor (DSP)-based drive system. This DSP-based drive system is then compared with conventional BELBIC and an optimized conventional PI controller. Results show that the proposed method performs better than the other controllers and exhibits excellent control characteristics, such as fast response, simple implementation, and robustness with respect to disturbances and manufacturing imperfections.

• Korean Journal of Applied Biomechanics
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• v.21 no.3
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• pp.345-352
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• 2011

The purpose of this study was to determine how spandex wear with compressive band affects biomechanical parameters during a golf swing. Nine male golf players, each with at least 6 years golf experienc(handy 4.5${\pm}$5.4), were recruited as the participants. Eight pairs of surface electrodes were attached to the left and right side of the body to monitor the pectoralis major(PM), external abdominal oblique(AO), erector spinae(ES), and vastus lateralis(VL). This study showed that the angular velocity of the club in EG were increased during the down swing phase but X-Factor and X-factor Stretch were reduced. Average and maximum nEMG (normalized EMG) values of the left AO(external abdominal oblique) were less in EG(experimental group) compared with CG(control group) during the back swing, whereas those of left PM(pectoralis major) in EG were greater than CG. It is more likely that EG performed effectively golf swing without excess muscle activity. Thus, the spandex wear with compressive band played an important role in improving swing performance with injury prevention. This has led to suggestions of the need for further kinetic and kinematic analyses to evaluate its function.

• Korean Journal of Applied Biomechanics
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• v.12 no.1
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• pp.205-219
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• 2002

This research seeks to identify the plantar pressure distribution graph and change in force in connection with effective golf drive strokes and thus to help ordinary golfers have appropriate understanding on the moving of the center of weight and learn desirable drive swing movements. To this end, we conducted surveys on five excellent golfers to analyze the plantar pressure applied when performing golf drive strokes, and suggested dynamic variables quantitatively. 1) Our research presents the desire movements as follows. For the time change in connection with the whole movement, as a golfer raises the club head horizontally low above ground from the address to the top swing, he makes a semicircle using the left elbow joint and shaft and slowly turns his body, thus lengthening the time. And, as the golfer twists the right waist from the middle swing to the impact with the head taking address movement, and does a quick movement, thus shortening the time. 2) For the change in pressure distribution by phase, to strike a strong shot with his weight imposed from the middle swing to the impact, a golfer uses centrifugal force, fixes his left foot, and makes impact. This showed greater pressure distribution on the left sole than on the right sole. 3) For the force distribution graph by phase, the force in the sole from the address to halfway swing movements is distributed to the left foot with 46% and to the right foot with 54%. And, with the starting of down swing, as the weight shifts to the left foot, the force is distributed to the left sole with 58%. Thus, during the impact and follow through movements, it is desirable for a golfer to allow his left foot to take the weight with the right foot balancing the body. 4) The maximum pressure distribution and average of the maximum force in connection with the whole movement changed as the left (foot) and right (foot) supported opposing force, and the maximum pressure distribution also showed much greater on the left sole.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.149-155
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• 2015

Purpose : Recently, many researchers and golf coachers demonstrated that X-factor and X-factor stretch had a co-relationship with driving distance. However, its relationship is still controversial and ambiguous. Thus, the aim of this study was to examine the relationship among X-factor, X-factor stretch and swing-related factors, including driving distance in elite golfers. Method : Seventeen male elite golfers (handicap: ${\leq}4$) with no history of musculo-skeletal injuries participated in the study. Thirty spherical retro-reflective markers were placed on including the middle point of PSIS, the right/left ASIS, the right/left lateral acromion of the scapula, driver head and shaft grip. All motion capture data was collected at 100Hz using 6 infrared cameras. Carry distance, club speed, ball speed, smash factor, launch angle, and spin rate were collected from radar-based device, TrackMan. Results : Pearson's correlation coefficient method was used to find the correlations among X-factor, X-factor stretch and swing-related factors. Positive correlations between driving distance and other swing-related factors which include club speed(r=.798, p<.001), and ball speed(r=.948, p<.001) were observed. In contrast to the swing-related factors, X-factor and X-factor stretch had no relationship to driving distance. Conclusion : These results indicate that X-factor and X-factor stretch are not key regulators in driving distance.

• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.421-428
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• 2012

The purpose of this study was to verify the effects of developed assisting wear which maximize trunk(back) muscle's stretch-shortening effect during backswing and downswing for increasing golf ball carrying distance. Design and fabrication of assistive wear were performed based on the results of analyzed data of trunk EMG activity from the golf drive swings of elite professional male golfers during back swing and downswing phases. After the prototype of wear was produced, surface EMG and Flight scope tests were conducted to verify the effectiveness of the wear for increasing distance to the professional golfers. Results indicated that wearing trial showed significant longer carry distance than the non-wearing trial(p<.001). The carry distance of wearing trial showed an average 229 m compared to the non-wearing trial, the average 225 m. The swing with wearing also produced significantly faster ball speed than the trial without wearing(p<.05). Average 245 Km/h and 244 Km/h were produced for the swing with and without wearing trails, respectively. EMG results also indicated that the muscle activity of left psoas was significantly increased for wearing trial during downswing and near the impact. Thus, this may affect positively to increase club head speed. The activity of the left latissimus dorsi was dramatically increased during the final stage of swing. This generates elongation effect for longer follow-through and increased impulse between club and ball so eventually valid assistance to increase carry distance. Therefore, the developed assisting wear was proved to be effective tool for increasing golf ball carry distance with maximizing trunk(back) muscle's stretch-shortening effect during backswing and downswing.

• Hwankyungkyoyuk
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• v.24 no.3
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• pp.34-43
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• 2011

Project-based learning is an innovative approach to learning that teaches a multitude of strategies critical for success in the twenty-first century. Students drive their own learning through inquiry activity, as well as work collaboratively to research and create projects that reflect their knowledge. The purpose of this study was to investigate the effects of eco-friendly school project activity which is applied from one of project-based learning approach on learning outcomes of students in ninth-grade environment course in middle school. The participants were given a questionnaire before and after the environmental project activities. In solving the school environment issues themselves, students have practiced invaluable problem solving skills. This study indicates that school students' awareness about the environment has positively changed by experiencing the eco-friendly school project. In addition, this project affects students' variety of environmental awareness. This project could be applied to school environmental education programs and to environment lessons, developmental activities or club activities for a positive impact on students' environmental awareness.