• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1017-1022
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• 2007

It is important to improve the initial launch conditions of golf ball at impact between golf club and ball to get a long flight distance. The flight distance is greatly influenced by the initial launch conditions such as ball speed, launch angle and back spin rate. It is also important to analyze the mechanism of ball spin to improve the initial conditions of golf ball. Back spin rate is created by the contact time and force. Previous studies showed that the contact force is determined as the resultant force of the reaction forces normal and tangential to the club face at the contact point. The normal force causes the compression and restitution of ball, and the tangential force creates the spin. Especially, the tangential force is known to take either positive or negative values as the ball rolls and slides along the club face during impact. Although the positive and negative tangential forces are known to create and reduce the back spin rate, respectively, the mechanism of ball spin creation has not yet been discussed in detail in the literature. In this paper, the influence of the contact force between golf club and ball is investigated to analyze the mechanism of impact. For this purpose, the contact force and time at impact between golf club head and ball are computed using FEM and compared with previous results. In addition, we investigate the impact phenomenon between golf club head and ball by FEM and clarify the mechanism of ball spin creation accurately, particularly focusing on the effect of negative tangential force on ball spin rate.

• The Research Journal of the Costume Culture
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• v.25 no.4
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• pp.499-508
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• 2017

Functional inner-wear being currently sold is being made without regard to the characteristics of various sports events. The purpose of this study is to identify this problem and to investigate the effect of sports taping on golf swing when wearing functional inner-wear. The subjects of this study were 8 male golfers belonging to Korea Professional Golf Association, and Launch monitor and Trackman were used to find out golf club action, ball pitch, distance, etc. There are three types of clubs: driver, wood, and iron, and the first experiment was carried out using only functional inner-wear. In the second experiment, we experimented with functional inner-wear after sports taping, and we compared and analyzed the distance depending on each experiment, the speed of the ball and the club, and the accuracy of the club face. The results of the study were as follows. As a result of driving distance, according to the presence of sports taping on functional inner-wear, there was a statistically significant difference in the driving swing and wood swing, for club and ball speed, there was a statistically significant difference only in the driving swing. Regarding the accuracy by the presence of sports taping on inner-wear, there was a statistically significant difference in the driving swing, wood swing, and iron swing. In conclusion, the sports taping in the functional inner-wear had a positive effect on golf performance improvement, and we hope that golf inner-wear these two specifications combing will be developed in the future.

• Asian Journal of Turfgrass Science
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• v.12 no.1
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• pp.1-16
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• 1998

Vegetation of golf courses and local difference of feeding host plants of brown chafer, Adoretus tenuimaculatus Waterhouse(Coleoptera: Scarabaeidae) were investigated in golf courses. Yongwon country club in Chinhae and Tongdo country club in Yangsan Gyeongnarn, Dongrae Benest golf club in Kumjeunggu Pusan and Daegu country club in Gyeongsan Gyeongbuk province from 1995 to 1997. Vegetation and species of feeding host plant were different depending on observed place. Damaged rate of host plants were concerned with ornamental trees and natural growing host plants, and Oenothera odorata, Achyranthes japonica, Aralia elata, Viburnum awabuki, Chenapadium album var. cent rorubrum, Cornus officinalis, and Rhododendron mucronulatum were newly recorded as host plant of A. tenuimaculatus in this study. Thus, host plants of A. tenuimaculatus were 193 kinds in 48 families. Key words: Brown chafer, Adoretus tenuimaculatus, host plant, vegetation, insect-plant interaction, biological control, golf courses.

• Journal of Biomedical Engineering Research
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• v.28 no.6
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• pp.744-749
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• 2007

Kinematic and kinetic analysis has been performed for Soft Golf swings utilizing realistic three dimensional computer simulations based on three dimensional motion tracking data. Soft Golf is a newly developed recreational sport in South Korea aimed to become a safe and easy-to-learn sport for all ages. The advantage of Soft Golf stems from lighter weight of the club and much larger area of the sweet spot. This paper tries to look into kinematic and kinetic aspects of soft golf swings compared to regular golf swing and find the advantages of lighter Soft Golf clubs. For this purpose, swing motions of older aged participants were captured and kinematic analysis was performed for various kinematic parameters such as club head velocity, joint angular velocity, and joint range of motions as a pilot study. Kinetic analysis was performed by applying kinematic data to computer simulation models constructed from anthropometric database and the measurements from the participants. The simulations were solved using multi-body dynamics solver. Firstly, the kinematic parameters such as joint angles were obtained by solving inverse dynamics problem based on motion tracking data. Secondly, the kinetic parameters such as joint torques were obtained by solving control dynamics problem of making joint torque to follow pre-defined joint angle data. The results showed that mechanical loadings to major joints were reduced with lighter Soft Golf club.

• Journal of Global Scholars of Marketing Science
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• v.15 no.1
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• pp.105-120
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• 2005

The research regarding the important attribute which gives an effect to golf club membership purchase. 1990's as the golf boom as percentage shows the rapid increase of the golf course visitor and it grows, from 2001 are passing over ten million people golf course visitors. When purchasing golf club membership, it is important from the research which it sees the attributes which it thinks probably are what, it grasped and the scope of research did Seoul and the metropolitan area golf user in the object and it executed an empirical.analysis. In order to raise the reality and a reliability of research also it executed the collection and a Question investigation and a empirical analysis of various statistical data. The result of research a frequency analysis, descriptive analysis, factor analysis, multiple regression analysis and a correspondence analysis used the SPSS/PC+ 10.0 which and is a statistics package program. The results show that four dimensions of image were derived from 14 important attributes, using a factor analysis. A correspondence analysis indicates that statistically significant relationships existed between some of Golf club membership factors with respect to the demographic variables of income and Golf frequency. A multiple regression analyses also indicate that most of Golf club membership factors had great impacts on visitors' recommend.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.111-117
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• 2017

PURPOSE: To determine the effect of weight ball throw training as a preparatory exercise before golf practice for 8 weeks on back muscle strength, weight shifting of lower body, head speed of club, and driving distance of amateur golfers. METHODS: A total of 18 subjects were randomly assigned to the experimental group (n=9) and the control group (n=9), respectively. For the experimental group, Weight ball throw training was provided to the height of waist and shoulder similar to golf swing with the following schedule: 3 kg weight ball throw training from the first week to the 4th week; 5 kg weight ball throw training from the 5th week to the 8th week. Before and after 8 weeks of training, back muscle strength, weight shifting of lower body, head speed of club, and driving distance of subjects in the two groups were measured. RESULTS: The experimental group showed significant differences in rotational back extension torque, weight shifting of lower body, head speed of club, and driving distance during golf swing (p<.05). However, the control group only showed significant difference in driving distance during golf swing (p<.05). Back extension torque, weight shifting of lower body, and head speed of club showed significant differences between the two groups during golf swing (p<.05). CONCLUSION: Weight ball throw training can positively change rotational back muscle strength, weight shifting of lower body, head speed of club, and driving distance of amateur golfers. Therefore, it might be used as an effective warming up exercise for amateur golfers.

• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.103-111
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• 2005

The purpose of this study was to analysis golf swing in accordance with each club using ground reaction force data. The subject of this study was current professional golf players in Korea. Golf clubs used for this study were driver, iron4, iron7, and pitching. The ground reaction force for left and right foot was collected by one Kistler and one Bertec force platforms. Also collected visual data by NC high speed camera to check the phase which was composed of address, top of backswing, impact and finish. Sampling rate was 600Hz both ground reaction forces data and visual data. The conclusion are as follows. 1. An aspect of change for ground reaction force was that the weight between the left foot and right foot were contrary to each other in general as the phase. 2. Without regard to the type of golf club, the ratio of necessary ground reaction forces for each phase in accordance with address, top of backswing, impact, and finish was comparatively identical. 3. According to the type of golf club, the tendency of Fy was not varied. In terms of Driver, at the moment of impact, the weight of foot-both right and left-was moved to the movement direction of golf because of the rotation force from swing.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.153-159
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• 2005

The purpose of this study was to investigate the Effective X-Factor in golf swing. The term X-Factor means the relative rotation of shoulders with respect to hips during the golf swing. To ascertain the Effective X-Factor that resulted in a high club head speed at impact six golfers' swing motions were videotaped and analyzed using three-dimensional techniques. The results can be summarized as follows. The standard deviations of the professionals' average club head speeds were higher than the amateurs'. This means that the professionals' swing skills were better than amateurs' in driving accuracy and consistency. As the club head speeds were increased gradually the X-Factors and the club head speeds had reached to the subjects' average club head speeds, but the X-Factors and the club head speeds were not increased above the subjects' average club head speeds. The X-Factor Stretch early in the down swing was existed and Professional stretched values were higher than the amateurs. In conclusion my research results suggested that the increase in Effective X-Factors had no relationship to the increase in club head speeds.

• Asian Journal of Turfgrass Science
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• v.24 no.1
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• pp.1-8
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• 2010

Occurrence of earthworms for turfgrass growing seasons and effect of earthworms by some plant extracts and plant oils in golf courses were investigated at the three locations golf courses in Korea 2005 to 2006. There were no differences in monthly occurrence of earthworm except Anseong Benest Golf Club, namely, Anseong Benest Golf Club was highly occurred in July in 2006. Density of earthworm was not different between fairway and rough in Dongrae Benest Golf Club (opened in 1971) while density was higher in rough than fairway in Anseong Benest Golf Club (opened in 1999) and Gapyeong Benest Golf Club (opened in 2000). In case of Gapyeong Benest Golf Club, earthworm density was higher in old courses than recently opened courses. Effect of plant extracts such as mustard oil, wintergreen oil, Quisqualis indica, Daphne genkwa, Pharbitis nil, Zingiber officinale, Xanthium strumarium, and Camellia sinensis on earthworm, mustard oil, wintergreen oil and tea saponin were highly toxic to earthworm, Eisenia andrei. In the pot experiment, 100% of Eisenia andrei was dead at the treatment of 500-fold of aquatic solution of tea saponin (12.4% a.i.).

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.380-392
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• 2013

A method to classify a golf swing motion into 7 sections using a Kinect sensor and a fuzzy system is proposed. The inputs to the fuzzy logic are the positions of golf club and its head, which are extracted from the information of golfer's joint position and color information obtained by a Kinect sensor. The proposed method consists of three modules: one for extracting the joint's information, another for detecting and tracking of a golf club, and the other for classifying golf swing motions. The first module extracts the hand's position among the joint information provided by a Kinect sensor. The second module detects the golf club as well as its head with the Hough line transform based on the hand's coordinate. Using a fuzzy logic as a classification engine reduces recognition errors and, consequently, improves the performance of robust classification. From the experiments of real-time video clips, the proposed method shows the reliability of classification by 85.2%.