Overview of the modern, total body golf swing
Click on any of the hyperlinks to rapidly navigate to another section of the review: Homepage (index); grip; address setup; backswing; downswing; impact; followthrough
There are many different ways of swinging a golf club, and I will not be discussing all the different ways of swinging a golf club in the main section of this review. In fact, I will primarily be discussing *one way of swinging a golf club, and this critical review is primarily devoted to an in-depth analysis of the modern golf swing, which has also been called a lower body golf swing or a total body golf swing.
(* Although the main section of my section is chiefly focused on describing the traditional/conventional swing, which is a left arm swinging methodology, I actually discuss many other swing styles in many review papers that are posted in the "miscellaneous topics" section)
Consider the mental image of a 10 year old boy swinging a golf club, and imagine that he has never previously hit a golf ball or previously had golf lessons. It is very likely that the boy will actively swing the club with his arms and hands, while his body passively twists about in space in reactive accomodation to the movements of the arms and club across the front of the body. This type of golf swing has been labelled the "tail swings the dog" type of golf swing, because the central axial torso has to reactively respond to the active movements of the appendicular torso (arms and hands). A 10 year old boy usually has a light, lithe torso that is very flexible and pliant and it can easily move about in space in reactive, but passive, response to forces generated by the actively moving arms/hands/club. Leslie King offers a free 12-lesson online tutorial on this type of arm-powered golf swing at http://www.golfpro-online.com/tuition/lking/index.html . This swing style is also taught by Peter Croker, an Australian golf instructor - see http://www.petercroker.com/englisch/multimedia/articels/seniorgolferapril.htm
In contrast to a 10 year old boy, most adult males, especially overweight middle-aged males, have a heavy, non-pliant central torso, which cannot easily twist about in space in reactive response to arm movements across the front of the body. Therefore, a more suitable golf swing for adults has been labelled a "dog swings the tail" type of golf swing, because the central torso ("dog") actively powers this type of golf swing while the arms/clubshaft ("tail") are passively swung around the rotating torso in response to forces generated by the large muscles of the central body.
When using a "dog swings the tail" type of golf swing, a golfer has to primarily move the central torso so that the shoulders rotate around the central torso's pivot axis. As the shoulders rotate, the arms are forced to move because they are attached to the central body at the shoulder joint, and the arms are passively flung around the body by the rotating shoulders. There are two general approaches to powering the shoulder turn in this type of golf swing. The one approach is called the upper body golf swing, because the golfer actively turns the upper torso (chest, upper back, shoulders) while keeping the lower body relatively passive and static. The second approach is called the lower body golf swing, because the downswing starts with a rotation of the lower torso (hips) followed by a rotation of the upper torso (shoulders). In other words, the swing starts from the bottom-up (lower body moves first, upper body second) while the upper body downswing starts from the top-down (upper body first and lower body second). Most professional golfers use the lower body golf swing and because both the lower and upper torso are involved in the golf swing action, it is also called a total body golf swing action. The lower body golf swing is the model that I use in this website's review papers - and I have arbitrarily labelled it the modern, total body golf swing.
Kinetic sequencing and the club release phenomenon
A key characteristic of the modern, total body golf swing is the fact that the major biomechanical events involved in the downswing action evolve in a certain set sequence - called the kinetic sequence.
Here is a graph demonstrating the kinetic sequence of biomechanical events in the modern, total body golf swing.
Kinetic sequence of the modern, total body golf swing
Rv = Rotational velocity = Angular velocity.
The kinetic sequence in the downswing action starts from the ground-up with a pelvic shift-rotational movement. A golfer actively shift-rotates his pelvis at the start of the downswing, using ground resistance forces in order to torque his pelvis in a shift-rotational manner. Shortly thereafter, the upper torso (shoulders) start rotating around a rightwards tilted spine. Some of the torque forces used to rotate the upper torso are passively transmitted from the lower torso to the upper torso via the spine and external torso musculature, but most of the torque forces are derived from the active muscle contraction of mid-upper torso muscles. The combined rotation of the lower and upper torso represents the pivot action, and the the pivot action essentially drives the swing from a swing power perspective. The arms are basically passive in a pivot-driven swing, and the arms are passively flung around the rotating torso as a result of the pivot-driven downswing action.
During the backswing, the left arm is pulled back across the upper chest, and it is essentially loaded against the upper torso by the end of the backswing. The left arm is inert in the modern, total body golf swing and it responds passively to movements of the upper torso during the downswing. When the shoulders start rotating in the early downswing, the arms are pulled along at the same speed as the rotating upper torso. In other words, the left arm is powered by the rotating upper torso. At a certain time point in the downswing (usually when the upper torso decelerates), the left arm is passively catapulted/blasted away from the chest wall and the left arm then freewheels towards impact. The energy used to propel the left arm towards impact is derived from the rotating upper torso, via the pivot-driven swing action. A modern, total body golfer doesn't actively pull the left arm away from the chest wall using his left shoulder girdle muscles (as occurs in an arm-powered swing - described by Leslie King).
When the left arm freewheels towards impact, it pulls the lagging club via the left hand, and this type of swing action is called the rope handle technique. In other words, the club is passively pulled along by the left hand - as if the golfer was simply pulling a piece of rope (like church bell ringers in the medieval era who pulled the bell rope in a groundwards direction in order to get the church bells to ring). At the end-backswing position, a modern, total body golfer usually has a 90 degree angle between the clubshaft and the left arm, and when the left hand pulls the grip end of the club during the downswing, the grip end of the club must obviously move as fast as the left hand. By contrast, the clubhead end of the club has inherent inertia and it lags behind the grip end of the club during the downswing.
The following diagram demonstrates how the clubhead lags behind the grip end of the club (and left hand) during the downswing.
Strobe photograph of Bobby Jones' iron swing
This strobe photograph demonstrates that the clubhead lags behind the left hand (grip end of the club) throughout the downswing and only catches up to the left hand (grip end of the club) at the bottom (low point) of the clubhead arc. During the early-mid downswing, the clubshaft-left arm angle remains at ~90 degrees, and the clubshaft only releases in the mid-late downswing. The club release phenomenon is a passive phenomenon and it is not due to any active uncocking action of the left wrist. In other words, a golfer shouldn't use any left forearm muscles to actively uncock the left wrist during the downswing. The club releases automatically/passively according to the principles of the double pendulum swing model.
Here is a diagram of a basic double pendulum swing model.
Double pendulum swing model
In this double pendulum swing model, there are basically two arms - a central arm (conceptually equivalent to the left arm) and a peripheral arm (conceptually equivalent to the clubshaft). There is a passive hinge joint between the two arms (conceptually equivalent ot the left wrist). During the swing, the central arm swings in a circular arc because it is suspended at the central hinge joint (conceptually equivalent to the left shoulder socket joint if one thinks of the left arm swinging in space, or the upper swing center situated midway between the left/right shoulder sockets if one thinks of the two arms swinging in space). To make it easier to understand, simply think of the left arm swinging in space - suspended from its central hinge point, the left shoulder socket. When the left arm (central arm) swings in space in a circular arc, then the left wrist (peripheral hinge joint) must also transcribe a circular arced motion in space. The clubshaft gets pulled along by the circular motion of the left wrist/hand unit (conceptually equivalent to the peripheral hinge point). If the peripheral hinge point (left wrist/hand) moved in a straight line direction - in the direction of the longitudinal axis of the clubshaft - then the club would never automatically release. The clubshaft would always remain at a 90 degree angle to the left arm - if the left wrist/hand moved in a straight-line direction towards the ground. The club only releases because the left wrist/hand moves in a circular manner - along a circular arced path. I demonstrate this automatic club release phenomenon in a short swing video lesson where I use a simple, home made double pendulum device.
Swing video demonstrating the double pendulum swing model - http://www.youtube.com/watch?v=fBu30VbvBRY
The key point that a golfer needs to understand is that the club releases automatically/passively because the left arm, and therefore the left wrist/hand, moves in a circular manner during the downswing. If a golfer simply uses his pivot-drive to cause the left arm to swing freely towards impact, then the circular arced motion of the left wrist/hand unit will cause the club to release automatically. A golfer doesn't need the right arm/hand to apply swing power in a pivot-driven swing, and a golfer doesn't need the right arm/hand to induce the club to release in the modern, total body golf swing.
The power accumulator loading and release concept
Many golf instructors teach a pivot-driven swing and they mainly concentrate their teaching efforts on teaching their student golfers how to improve the pivot action. They regard the arms as being passive in a pivot-driven swing, and they simply teach their students to allow their passive arms to be flung passively around the rotating torso secondary to the pivot-drive action. I think that there is a much better way of understanding and teaching a pivot-driven golf swing, and the first part of this learning process is understanding that the pivot-drive only initiates the downswing swing action. I think that it is very important that all golfers fully understand the "complete mechanical details" with respect to the "mechanism" of how the pivot-drive action eventually translates into a fast clubhead speed at impact.
I think that the best way of understanding the fundamental mechanics of the golf swing is for a beginner golfer to study and understand Homer Kelley's power accumulator loading and release concepts . Homer Kelley's TGM-book  is extremely difficult to read and understand and it took me a few hundred hours of intense study to clearly understand his TGM concepts. During the past year (2008), I have radically modified my review chapters, and I have also added more review papers, to reflect all these TGM influences, and hopefully my website readers will understand all the TGM concepts that I have incorporated in this webite's golf instructional review papers and swing video lessons.
I have described Homer Kelley's power accumulator loading and release concepts in great detail in a review paper called How to Power the Golf Swing, and I will merely outline the bare details in this overview chapter.
Homer Kelley essentially believes that a golfer powers the golf swing via the arms, and he believes that the pivot-drive action activates the release of arm power, but it doesn't power the clubshaft by itself. Homer Kelley describes a process of loading one's power accumulators during the backswing into a power package assembly. Then, during the downswing, the pivot-drive action delivers the power package assembly down to a release point where the power accumulators are released. When the power accumulators are released, they cause the clubshaft to be propelled at an optimum speed through the impact zone. There are two distinct patterns of releasing the power accumulators, and the one pattern is a swinger's pattern and the other pattern is a hitter's pattern. Each individual golfer needs to clearly understand the differences, so that he can decide whether he wants to become a swinger or a hitter. The modern, total body golf swing action is essentially a swinger's action.
It will be easier to understand the concept of power accumulator loading and release if you consider this visual example of a swinger's action - derived from Kevin Na's swing video .
Kevin Na's power accumulator loading and release - capture images from his swing video 
There are four power accumulators (PAs) and they are loaded during the backswing action. The master power accumulator is PA#4 and it supplies most of the power in a swinger's action. PA#4 is loaded when the left arm is pulled across the upper chest wall during the backswing so that there is an acute angle between the left arm and the chest wall between the shoulder sockets - see blue lines. PA#2 is loaded when the left wrist cocks upwards during the backswing, so that the left arm-clubshaft angle is ~90 degrees by the end of the backswing - see red lines. PA#1 is loaded when the right elbow bends to a 90 degree angle during the backswing - see yellow lines. PA#3 is called the transfer power accumulator and it transfers power to the ball after PA#2 releases, and it cannot be easily described in this image - but it is loaded when the left arm/forearm rotates-and-pronates clockwise during the backswing.
Image 1 shows Kevin Na at the end backswing position with all his power accumulators (PA#1, PA#2 and PA#4) loaded. During the downswing, Kevin Na is going to unload all his power accumulators by releasing all these angles. Power accumulator #4 is released when the left arm gets to a 90 degree angle relative to the upper chest wall. PA#2 is released when the left wrist uncocks fully so that the left arm-clubshaft have a straight line relationship, and PA#1 is released when the right elbow straightens fully. These power accumulators are fully released by the end of the followthrough (defined as the time point when both arms are fully straight) - image 4. In other words, the power accumulators are not fully released by impact - image 3 (note that the right elbow is still slightly bent and the left arm does not yet have a straight line relationship with the clubshaft). A golfer powers the clubshaft by fully releasing all these power accumulators in the optimum sequence, and the optimum sequence depends on whether a golfer is a swinger or a hitter.
A swinger releases his power acummulators in a set release of sequence of 4:2:3. A swinger starts the downswing with a pivot-drive action that delivers the power package intact down to about the waist-high position. Then, when the pivot-drive action subsides/decelerates, the left arm is blasted/catapulted off the chest wall - see image 2 - and that action represents the release of PA#4. All the other power accumulators are still fully loaded at this time point of the initiation of the release of PA#4. The second power accumulator to be released is PA#2 and it releases in the late downswing (between the delivery position and impact) - see image 3. The release of PA#2 is passive and it is due to a centrifugal action - as described in my double pendulum swing model demonstration. Note that the back of Kevin Na's flat left wrist/hand is parallel to the ball-target line in image 2, and facing the target at impact in image 3. That means that the back of the flat left wrist/hand undergoes a 90 degree roll-over (90 degree rotation) in the late downswing, and that roll-over of the flat left wrist/hand represents the release of PA#3. Note that the right elbow straightens in the late downswing, but this right arm straightening action is not active in a swinger (like Kevin Na). The right arm only straightens with enough active speed in a swinger's action, so that it can keep up with the left arm (which was actively released by the pivot-drive action). In a swinger's action, the right arm does not straighten forcefully in the late downswing in the form of a very assertive thrust action that applies push-force to the clubshaft in a drive loading manner. In other words, a swinger doesn't use any right arm push-power to propel the clubshaft towards impact.
A hitter releases his power accumulators in a set release sequence of 1:2:3. A hitter also starts the downswing action with a pivot action that delivers the entire power package intact to its downswing release point. However, a hitter doesn't use his pivot-drive action to actively release PA#4 - to actively blast the left arm into orbit. A hitter primarily uses the pivot action to move the right shoulder (which is the launching pad for the release of PA#1) sufficiently far enough downplane before he releases PA#1. A hitter basically powers his golf swing via the release of PA#1 - via an active right arm straightening action that pushes the clubshaft towards impact. When the right elbow actively straightens in the mid-late downswing in a straight-line thrust action, it causes the right hand to push the left arm and the clubshaft towards impact. There is no centrifugal release action in a hitter's action, and a hitter drives the clubshaft towards impact via the active release of PA#1 - and this drive-loading action is called an axe-handle technique (in contrast to a swinger's rope handle technique). In other words, a hitter uses PA#1 to simultaneously release PA#2 and PA#3. For those website visitors who are very interested in learning about hitting, I have described a hitter's action in great detail in my review paper on How to Power the Golf Swing.
I believe that it is very important that every golfer fully understand the differences between a swinger's action and a hitter's action, because I believe that it is a major mistake to mix swinging elements with hitting elements. A golfer who uses swinging elements and hitting elements in the same swing is called a switter, and I believe that it much more difficult to swing a golf club in an efficient and consistently precise manner if one is a switter. When I started to play golf I was a quintessential switter, and my golf swing became much more efficient and much more consistently precise when I eliminated my switting tendencies by becoming a much more "pure" swinger. I strongly advise every golfer to either become a swinger or a hitter, but never a switter. It is extremely difficult to acquire a consistent golf swing if a golfer is a switter.
Keeping the clubshaft on-plane
A golfer not only needs to learn how to apply swing power in the optimum manner when swinging the golf club during the donwswing - he also needs to learn how to keep the clubshaft on-plane throughout the downswing so that he can hit the ball straight.
Homer Kelley described how a golfer should keep his clubshaft on-plane in his TGM book . I have described the methodology of keeping the clubshaft on-plane in great detail in a number of my review papers and in a number of my swing video lessons. I am not going to describe the process of keeping the clubshaft on-plane in this overview chapter, but it is very important that every golfer learn to keep the clubshaft on-plane during his downswing/followthrough if he wants to learn how to consistently hit the ball straight.
A perfect example of an on-plane swing is Anthony Kim's swing - as exemplified by this swing video .
If you watch the swing video, then you will see that Anthony Kim keeps his clubshaft on-plane during both the backswing and downswing.
Anothony Kim's on-plane downswing
Anothony Kim's clubshaft is always on-plane throughout the downswing, because the end of the clubshaft (that is nearest the ground) always points at the ball-target line - see yellow dotted lines - whenever the clubshaft is not parallel to the ball-target line.
By keeping the clubshaft perfectly on-plane throughout his downswing and followthrough, Anthony Kim is generating a perfectly symmetrical clubhead arc that is perfectly in-to-square-to-in relative to the ball-target line at impact. I believe that every golfer should attempt to generate a perfectly symmetrical clubhead arc that is in-to-square-to-in through the impact zone.
Finally, the icing on the cake for a serious golfer is learning how to control the clubface through the impact zone, so that the clubface is square at the exact moment of ball-clubface separation. If the clubhead swingarc is in-to-square-to-in through impact, and the clubface is square at impact, then it is very likely that a golfer (who uses the modern, total body swing) will achieve a straight ball flight.
It is my belief that there is no precise definition of a perfect golf swing and different golf instructors have different personal definitions. However, I also simultaneously believe that a perfect golf swing has to have certain elements in order for it to be described as being "perfect". A perfect golf swing must allow a golfer to swing the golf club in a very efficient manner, so that he can maximise his swing power (like Ben Hogan and Tiger Woods). A perfect golf swing must also allow a golfer to consistently hit the ball straight, and I believe that an on-plane golf swing (like Anthony Kim's golf swing) makes that goal more easily achievable.
I fundamentally believe that every golfer needs to learn to have "educated hands". The concept of "educated hands" means that a golfer needs to learn to know what he is doing with his arms, elbows, forearms, wrists, and hands at every moment during his swing so that he can optimally control the movement of his clubshaft, clubhead and clubface throughout the swing. I have expressed my opinions regarding "educated hands" in great detail in my review paper called "How to Move the Arms, Elbows, Wrists and Hands in the Golf Swing". In a pivot-driven swing, like the modern, total body golf swing, the pivot action must be subservient to the needs of the arms/hands to be in total control of the swing, and people often use the TGM-term "hand-controlled pivot" to describe the situation where a golfer's "educated hands" directs the pivot-drive action to deliver the hands, and therefore the clubshaft, into impact as perfectly as possible. The precise details regarding my opinion on how best to execute the modern, total golf swing (using a hand-controlled pivot action under the directorial control of "educated hands") can be found in my multi-chapter review of the modern, total body golf swing and the associated review papers.
Original version: December 2006.
Revised version: February 2009.
1. The Golfing Machine. Homer Kelley.
2. Kevin Na Swing Video
3. Anthony Kim swing video.