The Kinetic Chain

Tue, 01/05/2010 - 14:00 -- Don Trahan

Today we are featuring a guest writer for the daily article which, at the same time, is serving as his introduction to all of you. He has become a very good friend in a real short time.‚  His name is John D'Acquisto, PhD.‚  I met him through his company, JD Consulting, a biomechanical research company that specializes in sports and human performance solutions, analytical sports studies, agricultural research and development studies .

I met Dr. D., as I call him, last December 1, when he and his team flew into Hilton Head. SC to conduct a biomechanical study of golf swings, including the PPGS.‚  The evaluation of the data is close to complete and we will, with Dr. D., be releasing the results within the next few months.

Anthony wrote a question to me in yesterday's article that I was sure Dr. D. would love to dive into with a biomechanically accurate answer that I am sure ya'll will love.‚  He told me his answer is basically supported from data accumulated in the December 1 study he conducted with us.‚ ‚  So, sit back and enjoy some serious science oabout the golf swing.

Dr. D‚  wrote a short bio of himself so I will say no more and let him introduce himself.

The Surge!

Doc D says:
My name is Dr. John D'Acquisto. I have been working with the Peak Performance Golf Swing as a scientist in Exercise Physiology and bio-mechanics for the last couple of months. I have studied biomechanical engineering with the best in the field I also played professional baseball for over 16 years. I went 12 seasons in the MLB. I am a 7.2 index handicap golfer and I have been working on golf swings since 1990 with some of the major players in the PGA.‚  I completed a study for the Peak Performance Golf Swing group and we are now seeing other parts of the data that are raising other questions, yet it is also giving us the answers we are looking for.

One of the main questions is:‚  How does muscling up in the golf swing effect the kinetic chain sequence of a golfer? Whereas a particular question was asked in the context below.

Anthony says:
If you try to swing your arms faster, won't that cause you to muscle up? This would create a thight golf swing. A baseball pitcher generates ball speed from arm speed and leg drive. What is different about a golf swing? I thought a golf swing starts from the ground up with leg drive. If you just use your arms to swing faster, won't that cause you to cast the club? Please clarify this concept of swing the arms faster..

Dr. D, says:
First of all, the kinetic sequences involved in the golf swing should start from the bottom and work up the body, instead of from the top down. From the top down creates casting and outside to inside swings or over the top, the golfers worse enemy.

Here¢€™s why the generation of the Kinetic Chain is important:

1. You reduce the risk of back injury.
2. This is the major difference between the Pros¢€™ and an amateurs¢€™ golf swings
3. You perform more consistently, especially under pressure.
4. There is an efficient flow of motion, so you can swing easy at the ball instead of trying to muscle up!

Power Generation Process – Kinetic Link Concept

The kinetic link (sometimes referred to as the kinematic sequence) is the concept upon which speed or power is created.‚  This concept applies to all hitting or throwing sports and it involves speed/momentum transfer from the large body segments to the smaller body segments.

The golf-specific kinetic link can be visualized as a system composed of four segments and three links.‚  The segments are the Pelvis (hips), the shoulders (upper Body), the arms and the club head.‚  The links are the muscles that connect each segment.‚  For example, the trunk muscles connect the hips segment to the shoulders segment.

Before the backswing is completed, efficient golfers are already starting the downswing from the ground up.‚  As their feet push into the ground forces are created that starts to accelerate their hips towards the target.‚  Force is generated to the ground and then is bounced back into the body through the segments.‚  It is a very firm yet not tight, controlled motion.

Once the hips (red line) reach their maximum speed they start to slow down or decelerate.‚  This ¢€œbraking¢€ action transfers speed to the shoulders segment, which accelerates to a maximum value usually twice that of the hips, or in a 2 to 1 ratio of acceleration.‚  As the shoulders (green line) segment reaches peak speed they start to decelerate.‚  Speed is now transferred to the arms, which accelerate even faster.‚  As the arms (purple line) are approaching impact they decelerate rapidly transferring a huge amount of speed or momentum to the club head. The club head (yellow line) then releases into impact with maximum velocity. The vertical green line represents the impact point of the ball to club head. It is interesting to note that the arms reach peak speed before impact not at or after impact. ( see the graph below)

Common power leaks include:
Hip Slide
Hip Rotation
Arm-Push

A Hip Slide occurs when the hips move laterally or slide from right to left, more than 2″ in the transition phase during the downswing.‚  No rotational hip speed is created.‚  Often times the hip slide is accompanied by a spine tilt to the right side.‚  Now the muscles on one side of the trunk are lengthened, while muscles on the opposite side of the trunk are shortened.‚  This asymmetry causes inefficient power generation.

A hip rotational spin occurs when the golfer tries to excessively rotate the hips on the downswing.‚  Now the lower body outraces the upper body and too much lag is created between the hips and the shoulders.‚  The potential energy that could have been used to accelerate the shoulders is wasted and power is lost.

An ¢€œArm-Push¢€ pattern occurs when the arms do not decelerate or slow down rapidly before impact.‚  The arms are forcing or pushing the club through impact.‚  In many cases the arms reach peak speed after impact.‚ ‚  This action disrupts the normal speed transfer process from arms to club.‚  The club release speed is significantly decreased and potential power is lost.

Common Misconception: Hold the Angle
When we look at the motion of efficient golfers on 3 D motion capture systems or videotape, it appears that they are ¢€œholding¢€ the club shaft in a cocked position deep into the downswing.‚  Many amateurs, in an attempt to create more power, try to emulate this action.‚  What you have to understand is that efficient golfers do not manufacture or try to hold this cocked position.‚  The arms accelerating around the axis of the trunk on the downswing create this club lag or cocked position.‚  When the arms decelerate before impact, speed is transferred to the club.‚  The club accelerates and the angle between the arms and club shaft increases rapidly into impact.

When you talk about muscling up to hit a golf ball, that is when things go wrong. Speed is created by fast twitch muscles and red fibrous muscle groups. If you tighten your red fibrous muscle groups you are restricting the flow of energy to each segment of the kinetic chain. Always remember to be firm, not tight, in your swing. Most amateur golfers experience this problem when they play. If you look at a professional golfer when he or she swings a golf club your comment usually is that, “Gee, they swing so smooth and effortlessly.” Well they do because they use their kinetic sequences to create the speed.

I tend to look at this as I would look at a tachometer in a car. The tachometer is set from 0 to 9 in some cars. Yellow is around 6, Orange is around 7 and redline is 8 to 9, for example. That tells you when you have gone to far. When you take that same principle and apply it to the golf swing, or in any sport, you will find that it holds true.

If you stay within your circle of ability you will be more consistent with your shots. Do what you are capable of doing. Once you try to do more than you are capable of doing is when mistakes happen. Like muscling up to hit the ball. If you want distance, you use a driver. If you want a controlled shot to the green, you use an iron. And if you want finesse shots, you use your wedge.

Good golf game habits are important to be able to play the game and enjoy it. Most amateurs want to hit the ball like a PGA Professional. Well, don't you think that if you could hit the ball like a PGA Pro, you would probably be playing on the Tour?

The wake up call is that you are not a PGA Professional, so don't try to play like one unless you really want to be a PGA Pro. Stay within your circle of ability and don't do more than you can do. Remember the tachometer. Once you leave the envelope or the maximum point of your circle of ability you are now in the orange area or redline area of your swing.

When you muscle up your large muscle groups contract more and freeze or lose their flexibility. The key word is flexibility here. When those large muscle groups freeze they restrict the flow of energy or block the energy through the swing's kinetic chain sequence; which generates power and speed to the club head. Use your whole body, not just a part of your body, when you swing the club, like your arms. Remember pelvis, upper torso, arms, club is the proper sequence to practice.

The Peak Performance golf swing or limited turn golf swing, when done correctly, will help control the golfer¢€™s bad habit to muscle up. You have less rotational factors in your swing in a more vertical position, taking the stress off the lower lumbar. When you are feeling no pain, you will gain confidence with every shot because you can hit the ball without interrupting the kinetic chain sequences in you swing. This swing is not perfect, yet it is the closest thing to the perfect golf swing that I have seen as a scientist and a golfer. It is easy to use and doesn't make you think a lot about what you have to do to hit a great golf shot. The rest is up to you.

Dr. D

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