레슨/Information2011. 8. 1. 07:55

퍼팅의 메카니즘은 시계추 원리이다.
시계추는 진자운동으로 중심을 기점으로 좌우로 움직이게 된다.

퍼팅은 드라이버 스윙처럼 파워를 내는 특성보다 감각적인 운동신경을 가지고 기교를 중시한다.

그렇다고 감각에만 치우쳐 타격원리를 무시하고 퍼팅을 하면 난감한 결과를 가져오게 된다.

민감하고 센티멘탈하기 때문이다.

골프를 하면 할수록 퍼팅이 매우 중요하다는 느낌을 갖게 된다.
퍼팅은 방향성과 거리를 확보해야하는 필드에서 마무리를 해야 하는 종착역이다.

드라이버샷이나 아이언샷을 잘해놓고 온그린 상태에서 쓰리퍼터나

제대로 홀인이 되지않는다면 다된밥에 코빠트리는 결과가 된다.

퍼팅에 있어 가장 많이 나타나는 현상은 볼을 일직선으로 보내지 못하고

홀 왼쪽으로 흐른다는 점이다.

이는 퍼팅시 느끼지 못할 정도로 양손을 안쪽으로 잡아채거나

왼손보다 오른손으로 과도한 힘을 쓰게 되어 나온 결과이다.

 

 

                                                                             [이봉철 프로] 

이를 방지하기위한 기본원리는 진자운동이다.

시계추가 좌에서 우로, 우에서 좌로 왕복운동 하듯이

외부의 힘에 방해되지 않게 자연스럽게 움직여져야 한다.

이러한 좌우 움직임에 인투인이라는 퍼터 헤드의 궤도를 추가해

움직이게 하면 원하는 목표에 도달하게 된다.

비기너 골퍼들은 직선으로만 치려다 보니 좌우 진자운동을 스퀘어하게만 보내려고 한다.

백스윙에서 다운스윙으로 퍼팅을 하면서 너무 직선으로만 치게되면 양팔이 경직될뿐더러

전체적인 어드레스 자세까지 흔들리려 예기치 못한 결과를 초래하게 된다.

퍼팅의 임팩트존에서는 좌에서 우로 움직여지는 스윙이 스퀘어한 형태가 되겠지만

임팩트존을 벗어난 스트로크의 경우 헤드가 몸에서 멀어질수록 안쪽으로 들어오는

스윙의 궤도가 자연스럽게 만들어지는 형국을 스퀘어한 형태를 만들기 위해

인위적으로 양팔을 사용하면 퍼팅 스윙의 궤도인 인투인이 깨트려진다.

퍼팅은 완벽한 방향성은 인투인 진자운동으로 해결하고

거리조절은 백스윙의 스트로크로 연습되어야 한다.

거리조절은 비기너들이 감각적으로 힘의 강약으로 조절하는 방법과

투어프로들이 즐겨하는 백스윙의 스트로크 크기로 조절하는 방법이 있다.
당연히 거리의 조절은 힘의 강약으로 거리를 조절하는 방법보다는 백스윙의 크기로 조절해야 한다.

숏 퍼팅은 백스윙을 작게 하고 롱 퍼팅은 백스윙을 크게 한다.
거리를 산정하는 방법은 발걸음 횟수로 거리를 산정하면 일관된 거리를 가질수 있다.
정확한 미터나 야드로 퍼팅의 거리 계산을 하게 되면 그린에서 일정한 시간내에서

골프게임을 하여야 하는 상황에서는 쫒기거나 바쁘게 퍼팅을 하게되어 짧거나 긴 퍼팅의 결과를 초래하게 된다.

미터나 야드 계산법을 무시하고 자신의 보폭에 맞는 발걸음 걸음 수로 측정을 하게 되면

쉽고 편리하게 계산되면서 정확히 자신의 성과를 가져갈수 있다.

필자의 거리 계산법은 퍼터 헤드 1개 길이의 백스윙 크기가 발걸음 3걸음의 거리를 나타낸다.

6걸음인 경우는 퍼터 헤드 2개의 백스윙 크기, 9걸음인 경우는 퍼터 헤드 3개의 길이 만큼

백스윙을 하면 일관되고 정확한 거리 계산이 된다.

그린을 읽고 거리를 산정하기위해 발걸음을 걸면서 거리를 세고

자신의 퍼팅자세와 템포에 맞게 지속적으로 연습을 하게 되면

완벽한 퍼팅 감각을 세우는 좋은 방법이 된다.
이봉철/ 동양골프장 프로·한국GTL골프아카데미 전임강사
[무등일보]

 

Posted by 프로처럼
레슨/Theory2011. 7. 24. 15:32
The laws of physics applied to golf course maintenance practices.

MOST ALL putting greens are neither level nor plane, some being more or less severely contoured and sloped than others. Consequently, Stimpmeter readings, taken over such dissimilar surface profiles, correlate differently as a linear measure of green speed. That is to say, green speed ratings, popularized as they have been by averaging Stimpmeter measurements taken on reasonably level greens, do not fairly and accurately serve as speed indices common to all putting greens. Rather, by preparing an "as built" green to Stimpmeter readings adjusted for its inherent angularities, uniformity of speed can prevail from green to green, stabilizing the composures of golfers and green superintendents in the process. By mathematically interpreting the physics fundamental to a golf ball rolling over a putting green upon release from a Stimpmeter, indices are derived, as angularity-consistent measures of speed rating characteristic of "as-built" slow-tofast greens. These indices are graphically plotted to facilitate their use by golf course superintendents, golf committees, tournament officials, and the like.





Putting distance depends on the green speed !!!

ARTHUR P. WEBER, a chemical engineer by training, has given generously of his time to golf as a USGA Green Section Committee member since 1984. He is a former green chairman of Old Westbury Golf and Country Club, Old Westbury, New York, and past president of the Metropolitan Golf Association.

[Source] http://turf.lib.msu.edu/1990s/1997/970312.pdf
Posted by 프로처럼
레슨/Theory2011. 7. 24. 15:14

 




The putting distance can be calculated by clubhead velocity !!!


[Source]
http://www.nature.com/nature/journal/v405/n6784/full/405295a0.html

Posted by 프로처럼
레슨/Theory2011. 7. 24. 14:42


Rhythm and timing are generally guiding human movements. Consistent rhythm and timing are crucial for high consistency of the complete stroke. Proper rhythm and timing are the basic principles in skilled movement performance.
The graph shows the time of backswing, the time from beginning of forward swing to impact, and the time of the complete forward swing in bar charts. Time to impact is also marked with a horizontal line inside of the forward swing bar. The grey areas indicate the preferred range of the timings of the PGA Tour sample. The average time values are shown below the bars.

Backswing time
Backswing time should be generally about 100-200 ms shorter than forward swing time. Backswing duration of 600-700 ms is in the preferred range of PGA Tour Pros.

Time to impact
Time from beginning of forward swing to impact is approximately half time of backswing time (see 8.3) which would mean 300-350 ms.

Forward swing time
Forward swing time should be generally about 100-200 ms longer than backswing time. The putter swinging on its own has a cycle time of about 950 ms. Forward swing time is approximately in this range. Forward swing duration of 800-900 ms is in the preferred range of PGA Tour Pros.

The absolute times can differ between different stroke types, more aggressive (committed) players generally show shorter times and more cautious (anxious) players show longer times. However, rhythm and timing (the relation of the components) should then still be in a preferred range (see 8.3). In other words, the complete stroke can be somewhat slower or faster, but rhythm and timing are always the same range.

[Source] SAM Puttlab - Report Manual
Posted by 프로처럼
레슨/Theory2011. 7. 24. 14:19


[Reference]
Ryan Burchfield, S. Venkatesan, "A Framework for Golf Training Using Low-Cost Inertial Sensors," bsn, pp.267-272, 2010 International Conference on Body Sensor Networks, 2010, IEEE Computer Society

Abstract
Body Sensor Networks are rapidly expanding to everyday applications due to recent advancements in Micro-Electro-Mechanical Systems (MEMS) sensing, wireless communication and power management technologies. We leverage these advancements to develop a framework for the use of MEMS inertial sensors as a low-cost putting coach for golf. Accurate putting requires substantial control and precision that is acquired via significant practice. Unfortunately, many golfers are not aware that they are practicing flawed mechanics. An electronic coach has the capability to point out these flawed movements before they become the norm. Our framework is the first step to an electronic coach and consists of a model for a putting swing, the design of a custom sensor platform and the implementation of signal processing functions to accurately estimate the trajectory of the golf club. Based upon our model we propose the use of sensor fusion algorithms to increase accuracy without increasing hardware demands. The accuracy of the system is experimentally evaluated using a controlled test platform.
Posted by 프로처럼
레슨/Information2011. 6. 20. 16:45
June 18, 2010
By philcheetham

I recently captured the swings of a young female playing professional on the AMM3D golf full-body motion capture system using TPI 3D analysis. She had some issues with the kinematic sequence peaking order, it was not optimal; her thorax was peaking before her pelvis. I noticed from the graphs that she had both a little excessive sway in the backswing and a reverse spine angle at the top. After the analysis we worked on some real-time biofeedback; we set it so if she swayed more than an inch the computer would beep; after about 15mins of practice we again captured her swing. She was able to maintain stability without swaying; she also stopped the reverse spine action. Look what happened to the peaking order of her kinematic sequence; perfect!  She and her coach were both thrilled. Check out the kinematic sequence graphs below.

image

Posted by 프로처럼
레슨/Information2011. 6. 20. 13:08
Posted by Administrator at 8:19 PM
TUESDAY, APR. 06, 2010

Get Ready for 2010 Golf Season

Golf Swing Improvement -- K-Vest and TPI Golf and Fitness

It has been a while, but I think you will all find this very interesting.

All serious golfers strive to continuously improve their abilities. Even the best professionals have changed their golf swings with focus on improvement and consistency (more fairways hit, more greens in regulation, closer to the cup approach shots, etc. ).

There are at least 4 schools of thought regarding swing changes.

1. Leave well enough alone. That is, if you are doing well, don't fool with it, or, "if it ain't broke, don't go a fixin' it".

2. Everyone has their own basic swing characteristics, for example, Jim Furyk,  Mike Weir, Arnold Palmer, Lee Trevino, Moe Norman, Jamie Sadlowski, and Jason Gore. Use that swing and work on ball flight, shot consistency and accuracy.

3. Continually work on improving your swing. Fully study and evaluate swing positions, potential power leaks, ball flight characteristics, optimum equipment fitting, etc. and focus on improvements that will optimize performance and minimize any flaws.

4. Hey! I don't have enough time to practice, more or less work on swing changes.  Let's just play some golf!

The level of effort that you choose for working on improvement is personal. If you plan to compete with PGA tour professionals then you likely know the commitment that you must make. If you are competing with yourself to improve your game and lower your handicap, then either number 2 or 3, above, should start you in the right direction.

I work with all age golfers of different skill levels, although most are the average golfers who play on an occasional basis.

But, I spent most of my life in the world of industry where striving for continual process improvement is a daily requirement. So despite the fact that I am old, overweight, and have already had one heart attack, I want to continually improve my golf ability, and I want to find ways to better help my students with their game.

With this in mind, I decided to go through a more technical evaluation of my swing and see how it compared to players on the PGA tour.

K-Vest and TPI Swing Evaluation Process

A process that has been reported to provide a scientific evaluation of the golf swing and compare each swing to the typical swing of tour professionals is the K-Vest and Titleist Performance Institute (TPI) swing evaluation process.  I had heard about this in the past but did not pay much attention to it. 

During the winter I had fallen on ice and afterward had significant pain issues with my hips and legs. After an MRI, EMG, and other evaluations, my doctor sent me to physical therapy sessions.

The PT sessions were conducted by Detroit Medical Center (DMC) Rehabilitation Institute of Michigan staff at Novi, Michigan.  Katie Shea, DPT, and PT assistant Alison were excellent. They provided specific therapy and a series of exercise routines that helped minimize the hip and leg pain. These were focused at strengthening my core muscles in the pelvic area. (FYI, stationary pedal biking helped me the most to minimize my hip pain.)

A few weeks after I finished those sessions I was at a golf show and I met a physical trainer who is also TPI certified.  I decided to participate in a K-vest and TPI evaluation to better understand that process and to see if it could provide another step toward additional improvement and a higher level of play.

My session was conducted by Maria Carroll. Maria is a certified Titleist Golf Fitness Instructor Level 3 and is a physical therapist assistant in Lansing, Michigan. She is also a certified PGA Tour Fitness Consultant, and certified personal trainer.  She specializes in golf rehabilitation for persons who have been injured and want to be able to play golf again. (Contact Maria at maly57@live.com).

The K-vest / TPI evaluation is a two-part process. For part 1, you wear the K-vest. (Based on my session, the K-vest is comfortable and does not interfere with your swing.)

K-vest Set-up

As you swing, the K-vest measures the rotation and positions of your thorax area (upper body) and your pelvic area (lower body) and sends this information to a computer. The data is presented in a series of graphs and also in 3-D graphics.

For each of 4 positions during the swing, the Address, Top, Impact, and Finish positions, there is a data range that is typical for tour professionals. Your swing position data is compared to these ranges. 

Example: Generic graph

K-vest Data Graph

Additionally, the graphs compare the upper and lower body rotations during the swing.  There are suggested parameters as to when and where the lower and upper rotations should occur and be positioned during the swing. These parameters parallel the swing position ranges of top professional golfers.

Thorax and Pelvic Movement 

You can address the ball and slowly move through your swing positions and watch the computer screen 3-D graphics to see when you are within the suggested range and when you move out of the suggested range.

In my case, at address I was 0° square to the target line (both hips/pelvis and shoulders/thorax).  Typical tour professionals have a slightly closed stance with their thorax / upper body in the 7° to 17° range.

Stance Alignment

 The swing evaluation process also provides other data, such as your kinematic sequence (speed sequence from pelvis, thorax, arms, and club), and your spine rotation during the swing.

Part two of the session provides the evaluation, further evaluates your flexibility, and recommends a course of action based on the findings.

The K-vest / TPI findings

Despite good golf shots, my ability to create a swing that is in the comparable range to that of the tour pros was hampered by my lack of upper body rotation flexibility, marginal hamstring and leg flexibility, and my overall lack of good physical conditioning (I'm not 30 years old any more!). 

Pelvis / Hip Rotation Data

I had more than enough hip and pelvic rotation, but not enough upper body rotation in relation to the pelvic rotation. I coined the phrase "swollen core" (i.e., a protruding, overweight abdomen), and told Maria that it was getting in the way of good upper body rotation.

To better describe the upper body rotation vs. the overall rotation, Maria had me stand straight with my arms crossed with fingers touching my shoulders, and then trying to rotate my upper body without any hip rotation. This would provide the increased torque that would help increase swing dynamics.

Maria said that the focus of an improvement program for me would be to work on (1) my upper body flexibility, (including shoulder rotation without rotating my hips), (2) my overall core strength, including hamstrings and legs, and (3) reducing my "swollen core", i.e., lose some weight around my mid-section.

Interestingly, in a Golf Digest article, (Autumn, 2009 timeframe) Tom Watson suggested that as you become older and your flexibility decreases you must use your hips more to get the rotation that you need.

Even though it was demonstrated that I have good hip/pelvic rotation, despite my age I should improve my upper body flexibility and my overall flexibility and strength.  This will help my golf swing and my overall health.

For me, I see a two-fold benefit from the K-vest / TPI session and Maria's suggestions. The primary reasons for me to improve flexibility and physical fitness are to help avoid future injury, especially back injury, and to be able to continue playing golf and work at my own continual improvement.

A second benefit of being familiar with this process, however, is that I can provide greater help to my students. I can pay better attention to their fitness level and stress the importance of maintaining good physical condition with the help of a certified personal trainer like Maria. I can also pay closer attention to the kinematic sequence of movement from the pelvis, chest, arms and clubhead.

For example, I typically have students hold their lag position during the forward stroke, but a greater focus on the overall transition, including a delayed lag, may help students acquire a smoother, more consistent stroke. 

A video of my K-vest swing evaluation and fitness session can be viewed via the training website. Contact us to receive a password to login and view the video.

My Next Steps

Maria's suggestions provided a personal exercise plan to help improve my flexibility and core strength. The exercises take about 40 to 45 minutes and are similar to, but more aggressive than, those that I was completing for my physical therapy sessions.  Contact Maria at maly57@live.com if you want to customize a K-vest and "get fit" program for yourself.

Before you begin any exercise program consult with your personal physician to assure that you are healthy enough to begin a fitness program. Follow his/her direction.

Unfortunately, my ability to sustain a very aggressive fitness routine has been hampered by repeated injuries to old sport injuries and other injuries, including issues with both hips.  At my age and marginal fitness level I have found that I must pursue a less vigorous effort in order to continually work at improving my physical fitness.

Persons younger than me, or those who have maintained their fitness level better than I have, should not have any problems with the more intense fitness routine.

There are two programs, however, that I found work well for me and that I am able to routinely complete.

First, I have been able to resume the injury-focused personal exercise program that I was provided with by the DMC physical therapists.  That program was developed over several PT sessions, and those exercises are similar to the exercises that Maria offered during the fitness evaluation.

For us older, or less fit persons, a second program that I have tried that provides me an excellent workout without excessive stress is available to everyone via public TV. The Joel Harper DVD series of workouts, titled "Firming After 50", (Upper Body and Lower Body workouts) demonstrates 3 fitness levels of activity and provides excellent cardio and core strength-building fitness programs.  (Available from public TV at http://www.dptvmedia.org/Joel-Harpers-Firming-After-50-DVD-p359.html.)

Almost anyone should be able to complete those exercises, with permission from their personal physician.

As my fitness improves I may be able to increase the level of effort and resume the more aggressive program.

What should you do? Don't wait. Keep in golf shape and health shape. Start your own physical fitness activity program today. Make this golf season your best golf season ever.

I do believe that improving my level of fitness will help me continue to enjoy playing golf and teaching golf.  A K-vest golf swing and fitness evaluation program like Maria offers can help better golfers understand their swing, improve their fitness level, and become even more competitive.

An appropriate personal fitness program can help everyone better enjoy playing golf.

Contact me if you have any questions or comments regarding this article or the online golf instruction training courses, or if you would like to view the video or participate in an instructor-led Golf Training Program in southeast Michigan.

PS. Be sure to ask about our 2010 early season student specials for the SwingRite golf swing trainer and the Sports Senor's Swing Speed Radar with Tempo Timer, and about the new DVDs.

Hit 'em straight!

Phil Lawrence

Posted by 프로처럼
레슨/Theory2011. 6. 20. 12:50
Expert Author Neville Walker

Putting Smart is all about putting in such a way that everything in your setup and stroke helps rather than hinders your ability to make a good putt. Why make putting more difficult than it is?

There is no one right way to putt just as there is no one wrong way to putt. However, there are smarter ways to putt. Effective putting is all about reducing the number of potential errors and compensations - and maximising your chances of success.

Because there is no right way to putt, you can make any putting method succeed if you are prepared to work at it. However, most recreational golfers don't have the time or the motivation to spend endless hours perfecting their method. Better then to adopt a method that requires the least amount of maintenance.

Here are Four Ideas towards Putting Smart:

1. Reduce Excess Tension
In your setup you want to adopt a relaxed posture with enough tilt from your hips to allow your arms to hang naturally under your shoulders. This will help to promote a free swing of your putter. If your putter is too long for you, you will be forced to bunch your elbows up into your rib cage so that you can get your eyes over the ball. This can block your arms. You want to avoid any contorted or twisted position as if you were in a badly fitted suit.

Next you should hold your putter loosely enough so that someone could easily pull it out of your hands. If your grip pressure is too tight, tension will radiate into your arms and shoulders.

2. Align Square to your Target
There are a number of different stances from open to square to closed. All of then have been successfully used by professional golfers.

However, the more the line of your shoulders deviates from a line parallel to your target, the more difficult it will be to square your putter at impact. A square stance is less error-prone.

3. Quieten your Body Motion
Putting is a gentle activity which requires a minimum of motion. The ideal is to keep your head steady with your eyes focused on one spot while avoiding any lower body movement.

The only moving part should be the triangle that is formed by your shoulders, arms and hands. This should work as an integrated unit.

4. Avoid Chasing the Ball with your Eyes
A common mistake in putting dumb is chasing the ball with your eyes as you make your stroke. In the full swing this is known as looking up. When you do this, you pull your shoulders off line left at the critical moment of impact. The smart way is to hold your follow through and listen rather than look.

It is almost impossible to improve your putting without practice. However, if your putting method is based on sound fundamentals, your chances of success are better than if your putting method is flawed from the start. The trick is to learn to putt with the percentages in your favour.

Neville Walker has a passion for golf and is actively involved in researching information on all aspects of Putting and Putter Technology. His dedicated web site http://www.better-golf-by-putting-better.com is written specifically to help fellow golfers achieve greater success on the green with the flat stick.

Article Source: http://EzineArticles.com/?expert=Neville_Walker

Posted by 프로처럼
레슨/Information2011. 6. 12. 23:53

[중앙일보]입력 2011.06.10 00:05 / 수정 2011.06.10 00:05


[일러스트=강일구]

골프를 한다면서 퍼팅의 중요성을 모르는 사람은 거의 없다. 그렇지만 퍼팅 연습을 매일 꾸준히 하는 사람은 많지 않다. 통계적으로 퍼팅은 골프에 있어서 40% 내외를 차지하는 중요한 영역이다. 스코어에 미치는 영향이나 중요도로 보자면 그보다 더하면 더했지 덜할 리가 없다. 그런데도 사람들은 왜 연습을 소홀히 할까. 게다가 되도록이면 퍼팅을 안 해도 되는 골프를 끊임없이 꿈꾸는 걸까.

연습이 재미없어 그럴지도 모른다. 효과적으로 연습할 곳이 마땅치 않아 그럴 수도 있다. 어떤 이는 퍼팅 연습을 한다고 해도 금방 달라질 것 같지 않다고 푸념을 하기도 한다.

나는 마음골프학교를 운영하면서 ‘군용 담요 퍼팅 게임’이라는 걸 개발(?)해 학생들이 집에서 연습하도록 제안한 적이 있다. 군용 담요를 구겨놓은 뒤 그 위에서 퍼팅 연습을 하는 것이다. 퍼팅 거리감을 익히기엔 군용 담요만큼 좋은 게 없다. 더구나 담요를 구겨놓으면 자연스럽게 라인이 생겨난다. 군용 담요 퍼팅 게임을 개발하기 전에는 실내 연습장에다 9홀 게임을 할 수 있는 퍼팅 게임장을 만들어 놓기도 했다. 이런 방법은 아마추어 골퍼들에게 꽤 효과가 있었다. 모두들 즐기면서 퍼팅 연습을 할 수 있었기 때문이다.

개인적으로는 퍼팅으로 빙고 게임을 하는 ‘핑고’라는 제품을 만들어 팔기도 했다. 당구대처럼 퍼팅대를 만든 뒤 그 안에서 당구처럼 퍼팅 게임을 하는 것도 공을 들여 연구했었다. ‘핑고’가 잘 안 팔려 퍼팅 당구대는 출시도 못했지만 그 모두가 어떻게 하면 재미없는 연습을 따로 하는 것이 아니라 ‘게임을 즐기는 동안 퍼팅 실력을 향상시킬 수 없을까’ 하는 고민에서 나온 시도였다.

마음골프학교에서는 퍼팅이라는 공부 과목의 특징을 설명하면서 수능 시험의 국어 과목에 비유한다. 국어는 안 배워도 할 수 있지만 잘하려면 녹록지 않은 과목이다. 퍼팅도 꼭 그렇지 않은가. 초보자들은 자신들에게 별 의미도 없는 퍼팅의 자세나 원칙들에 얽매여 배우지 않고도 잘할 수 있는 일을 망치고 있고, 상급자는 엄청나게 노력을 해야 조금씩 발전해갈 영역을 그날 그날의 운에 맡기고 있다.
 
인터넷이나 방송에서 난무하고 있는 퍼팅의 각종 팁들은 3m 이내의 퍼팅을 10개 중 9개 정도 성공시키고 있는 사람이 10개 모두를 성공시키고자 할 때 필요한 형식적인 제안이라 이해해도 무방하다.

퍼팅의 방향성이 좋지 않다고 호소하는 사람들에게 공을 보지 말고 홀을 보고 퍼팅을 해보라고 하면 본인도 놀랄 만큼 금방 방향성이 좋아진다. 퍼팅의 거리감으로 고생하는 사람에게는 눈을 감고 온몸의 느낌으로 거리를 조절해 보라고 하면 그 또한 효과가 즉각적이다. 너무나도 많은 형식적인 제한들이 몸이 가지고 있는 본능적인 감각을 저해하고 있는 대표적인 예라 할 수 있다.

퍼팅은 기본기가 중요하지만 그렇다고 퍼팅 성공률을 높이기 위해 특출한 방법이 있는 것도 아니다. 그저 자연스러운 자세로, 즐기면서 퍼팅 연습을 하다 보면 저도 모르게 실력이 향상되는 것이다. 그런데도 퍼팅 레슨을 하면서 백스윙과 정확한 임팩트 운운하는 것을 보면 앞뒤가 뒤바뀌었다는 생각이 든다.

비록 이제까지 여러 사람의 다양한 노력이 실패했다고 하더라고 골프 인구 300만 명을 넘어서고 있는 이즈음, 게임을 즐기는 동안 저절로 실력이 향상되는 ‘퍼팅 게임장’이나 ‘게임바’ 같은 것이 생겨나길 기대해 본다.

 마음골프학교(www.maumgolf.com)에서 김헌
Posted by 프로처럼
레슨/Theory2011. 6. 11. 09:43
Giorgos Paradisis, Julian Rees   


Putting Analysis Result (Expert and Novice Golfers, 8ft distance)
Handicap (Expert 2.3, Novice 23)

Expert is...
1.More consistence (standard deviation x2~x3)
2.More fast putter head speed (Expert 1.16 vs. Novice 0.7 m/s)
3.Less face angle change of putter head (Expert 2 vs.Novice 4.2 degree)

숙련자와 초보자에 대한 8ft(2.5m) 퍼팅 분석결과
핸디캡 (숙련자 2.3, 초보자 23)

숙련자가 초보자에 비해서...
1. 일관성이 좋다 (표준편차 3배 차이)
2. 퍼터헤드 스피드가 빠르다 (숙련자 1.16 vs. 초보자 0.7 m/s)
3. 퍼터헤드 변화각도가 작다 (숙련자 2 vs. 4.2 degree)


The aim of this study was to identify some of the kinematic parameters used by expert golfers (less than or equal to 6 handicap) to optimise putting efficiency and accuracy, and differentiate the putting techniques of elite and novice golfers. A 2D video analysis (50 Hz) were used to establish whether any differences existed for selected kinematic parameters of an 8 ft (2.46m) golf putt between expert (n = 8) and novice golfers (n = 8). Statistical analysis showed that 9 parameters from the 26 measured proved to be significantly different at the alpha level P < 0.05 between the expert and novice groups. This study assumed that expert golfers were more competent putters than novice golfers. Whilst this appears to be a reasonable claim it may not always be the case. Further improvements to the study could be to incorporate a scoring system to monitor the outcome of individual trials.

Introduction

In the modern-day game of golf, putting remains the key to shooting low scores, and the ability to hole putts can turn a good round into a great round. It has been reported that putting accounts for approximately 40% of all golf shot played (Gwyn & Patch, 1993). However, golf practice does not seem to balance the percentage out between the golf swing and the golf putt. Virtually all golfers, regardless of their level of expertise suffer inconsistencies in putting performance due to the stroke being a complex and multi-faceted motor process. This is in part due to the fact that unlike golf driving, in which the need for maximum club head speed at impact largely determines the body actions that can be successfully employed, success in putting can be achieved using a variety of techniques (Cochran & Farrally, 1994). Despite this revealing statistic and the obvious importance of competent putting, much of the pedagogical literature is based on the observations and anecdotal evidence provided by top players and coaches. There is a general lack of published scientific research and information regarding the kinematics of the putting stroke is scarce. Thus, the aim of this study was to identify some of the kinematic parameters used by expert golfers (less than or equal to 6 handicap) to optimise putting efficiency and accuracy, and differentiate the putting techniques of elite and novice golfers.

Method

The study population consisted of right-handed amateur golfers from the University of Wales Institute, Cardiff (UWIC) and Celtic Manor Golf Club, Newport (CMGC). This population was separated into two groups based on their playing ability; expert (EX) (age 23.3 ± 3.3 yrs, height 1.80 ± 0.1 m, handicap 2.3 ± 1.8, experience 9.3 ± 2.1 yrs; mean ± s) and novice (NO) (age 26.5 ± 3.2 yrs, height 1.7 ± 0.1 m, handicap 25 ± 2.6, experience 1.5 ± 0.9 yrs; mean ± s). The expert subjects had all represented UWIC in the British University championship and were practising regularly at the time of testing. Conversely, the novices from CMGC were recreational players who played on average once a week.

In order to carry out the study it was necessary to set up an artificial putting surface to allow for maximum control of potential external variables. A flat Astroturf surface was marked out with white tape (4m x 1.5m) to yield a straight putt with no break. At one end of the putting surface was a standard golf hole (4 inches in diameter) and at the other end was a designated marker that ensured that the actual distance of each putt was equidistant, regardless of an individual's set-up technique.

The order of putts was randomised for each subject until all subjects had putted once and then the procedure was repeated. This reduced the effect of muscular fatigue on the putting stroke and any learning effect that would result from continuous putting.

Two-dimensional video analysis was used to capture three trials from each performer. A Panasonic F'15HS video camera was mounted upon Manfrotto 117 rigid stationary tripods 5 m away to capture a full field of performance. The camera was positioned perpendicular to the plane of performance, operating at 25 f/s with a 1/500 s shutter speed. Nine superficial markers were attached according to the guidelines suggested by Plagenhoef (1971) on the vertex of the head and both right and left joints (glenohumeral, elbow, wrist and knee).

Before the commencement of testing each subject was allowed a considerable putting warm-up and trial period. Firstly, this was to ensure that familiarisation occurred for the pace and nap of the putting surface, and secondly, each subject needed to become accustomed to the same ball and putter being used in the investigation. After the warm-up 2-D video data was collected for each subject performing a series of putts from a set distance of 2.46m (8 ft). It was explained that the purpose of the test was to determine an individual's normal putting technique for successful putts. The order of putts was randomised for each subject until all subjects had putted once and then the procedure began again. This reduced the effect of muscular fatigue on the putting stroke and any learning effect that would result from continuous putting.

Co-ordinate digitising was undertaken on an Acorn Archimedes 420/1 microcomputer equipped with the Kine System software (Bartlett and Bowen, 1993). Generalised cross-validated quintic spline that has been derived from a program by Woltring (1986) were then applied to remove random noise. Reconstruction was based on a user-defined 13-point model. To aid interpretation of results, key moments were introduced in the analysis to divide the stroke into five phases (Figure 1), as previously defined for qualitative analysis by Burden et al. (1998).

Figure 1

Figure 1. Typical stick figure sequences at five instants of the golf putt where kinematic parameters were measured. Ball address (1), Back swing (2), Through swing (3), Ball impact (4) and Follow-through (5).

The following parameters were calculated: ball position, stance width and wrist positioning at ball address (BA), and the putter-head horizontal and vertical displacement, subject's head movement - horizontal and vertical displacement, timing of the BS, TS, FT and total putt time, angular displacement of the right and left elbow and also the angle formed by a line joining the left elbow to left wrist and putter shaft, maximum horizontal linear velocity and time it occurs, at back swing (BS), through swing (TS) and follow through (FT).

Digitising Reliability: Reliability and objectivity of the digitising process was established by repeated digitising of one sequence at the same sampling frequency with an intervening period of 48 h. The limits of agreement method (Bland and Altman, 1986) was used to compare these repeated digitised sequences and produced values for the angular displacement of the left elbow (LE) and the horizontal displacement of the putter head (PH) based on the equation MD ± 1.96 SD, where MD = mean of differences between repeated digitised sequences and SD = standard deviation of these differences, as heteroscedasticity correlation was close to zero. Given these results (Table 1) it was concluded that the digitised data were reliable and objective.

Table 1

Results & Discussion

Statistical analysis showed that 9 parameters from the 26 measured proved to be significantly different between expert and novice players at the 95% level of confidence (Table 2).

Table 2


The present study's data for hand positioning confirmed a significant difference (P<0.05). It has been agreed previously that forward hand positioning locks the wrists into a firmer position, minimising wrist involvement and ensuring that the individual putts with the larger muscles of the shoulders (Leadbetter, 1997). It was therefore possible that the potentially more reliable forward wrist positioning method of the experts resulted from this variable.

There was a significant difference (P<0.05) for mean linear displacement of the putter head between BA to final BS position. However, in contrast the BC to final FT mean linear displacement was not found to differ significantly between the groups. There has not been any definite recommendations put forward for the displacement of the putter head for the relative phases of the putting stroke. Interestingly, the novice displacements tended to agree with the pendulum theory proposed by numerous experts over the years. Their displacements from BA to BS position and BC to final FT position were approximately equidistant. In contrast the experts tended to exhibit the modern theory technique where the putting stroke is executed with the BS being substantially shorter than the FT.

There was a significant difference (P<0.05) for head displacement change between the BS to BC phase. It maybe concluded that the more important factor was whether the head was stationary at the point of ball contact. This measurement was however outside the present study's scope.

Vertical displacement for the putter head during the BS and FT phases was significantly different (P<0.05) between the two groups. Experts were characterized by shallow BS and a more pronounced vertical displacement during the FT. In contrast the novice's vertical displacement during the BS and FT was far greater than both expert phases. The greater variability found in the novice group during the back swing and follow-through phases may have resulted from the breaking of the wrists.

Putting (1998) have referred to the fact that to achieve a crisp ball strike it is desirable to accelerate the putter through the ball hitting area from a slower BS. Consequently, as acceleration is a derivative of velocity it would be expected that the greatest velocity attained would occur at or just after the BC phase. This occurred for the expert golfers (range, 1.05 -1.3 s) but was somewhat more erratic for the novice golfers (range, 0.3 -1.2 s), therefore a significant difference (P<0.05) resulted. However, because all putts analysed were successful they must have been struck at similar velocities through the BC area. Consequently, as expected no significant differences were apparent between the actual maximum horizontal velocities attained. The novice group was however more erratic in the smoothness and velocity pattern during their stroke.

Recommendations for the relative timing of the phases under investigation do not directly exist. However certain authors (Leadbetter, 1997) refer to a slow BS and then an accelerating phase into and through the hitting area. Both groups were characterised by this general trend, the experts to a greater degree than the novices, therefore no significant differences existed. The only significant difference (P<0.05) that did occur was for the FT phase, however, this is not thought to be of any great significance towards putting technique.

The main limitations of the study were the homogeneous nature of the selected groups (expert and novice golfers) and therefore any post hoc justifications towards other groups were problematical and indeed limited. Although the collection of data in the controlled environment (golf practice bay) had advantages from the viewpoint of methodological considerations, it nevertheless, did not accurately simulate the real external or competitive situation. Finally, the analysis of only one putt per analytical investigation may not always be a true reflection of an individual's technique, and the validity of using a single performance trial per subject as being representative of generalised performance outcomes must be questioned (Bates et al., 1992).

This study assumed that expert golfers were more competent putters than novice golfers. Whilst this appears to be a reasonable claim it may not always be the case. Further improvements to the study could be to incorporate a scoring system to monitor the outcome of individual trials.


Posted by 프로처럼