Book Review: The Slot Swing - Jim McLean

 

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Introduction:

 

Jim Mclean recently published a book [1] on the "slot swing" and in this review paper I am going to describe Jim McLean's thinking regarding the "slot swing" and I am going to compare his descriptive approach to my personal (deeply-analytical) approach. When I started this website in February 2007, my main agenda was to provide a free online golf instructional manual for beginner golfers - based on traditional golf instructional teaching as taught by famous golf instructors (eg. Jim McLean and David Leadbetter). However, over the past few years, my knowledge of golf swing mechanics/biomechanics has increased tremendously, and I now think that there is a much better way to think about golf swing mechanics/biomechanics, and I have written a number of review papers describing my deeply-analytical approach to the subject. My many new review papers and revised basic chapters have become progressively more complicated, and they presumably only satisfy a sub-segment of golfers, who troll the internet for useful golf instructional material. I am increasingly inclined to primarily write review papers for that small sub-segment of golfers, who prefer my deeply analytical approach. In this review paper, I will be comparing my deeply-analytical approach to Jim McLean's more simplistic approach - regarding the subject of the "slot swing".

What is the "slot swing"? Basically, the "slot swing" is simply the technique that a golfer uses to bring his clubshaft down-and-forwards in the direction of the ball during the early downswing.  In his book [1], Jim McLean only uses drawings (superbly drawn by Phil Franké) and the following drawing depicts his concept of the "slot swing".

Slot Swing - from reference number [1]

Jim McLean believes that the optimum golf swing requires a golfer to drop the clubshaft down into the imaginary "slot box" during the mid downswing, so that the clubshaft can move along an inside-out path towards the ball. This concept is fundamental to the idea that a golfer needs to generate an in-to-square-to-in clubhead path as depicted in the following photograph.

Kevin Na's clubhead path - capture image from his swing video [2]

Kevin Na is generating an optimal clubhead swingpath - that is symmetrically in-to-square-to-in relative to the ball-target line, and you can see that his clubhead descends through an imaginary "slot box" in the mid downswing.

According to Jim McLean the clubshaft's path in the early-mid downswing must be neither too steep or too shallow, and he states that there is an acceptable corridor for the clubshaft's downswing passage in the early downswing. 

Slot corridor - from reference number [1]

Jim McLean uses the above drawing to demonstrate his "concept of an acceptable corridor" for the clubshaft's positional movement in the late backswing, and during the downswing the clubshaft should descend down that same corridor towards the opening of the "slot box" from a clubshaft position that is "somewhere" within the limits of that "acceptable corridor". 

In the next section, I am going to briefly describe certain key thoughts that Jim McLean propogates with respect to his "slot swing" concept, and in a subsequent section I am going to critically examine his thinking and describe my own personal approach to this subject. Website visitors can then independently decide which intellectual approach is most useful from their perspective.

Jim McLean's "slot swing" - a brief overview of his descriptive approach to the subject:

 

Jim McLean states in his book that his interest in the concept of the "slot swing" started in the early 1980s when he drew lines on a video monitor screen depicting the position of the clubshaft at different times during the backswing and downswing. He noted that "in nearly all swings, the shaft position in the backswing and downswing cross when the hands are at chest height. In 99 percent of professional swings, the downswing shaft position is flatter than the backswing shaft position". He also stated that "in numerous high-handicap amateur swings that we analyzed, the shaft postion at the three-quarter position going back was flatter than the shaft position coming down - the exact opposite of the positions featured in professional swings". The following series of photographs demonstrates an example of a golfer who has a very shallow (too inside) clubshaft path in the backswing and a much steeper clubshaft path in the downswing.

Shallow backswing clubshaft path and steep downswing clubshaft path - from reference number [3]

This series of capture images from a swing video demonstrates a golfer taking the club back along a too-inside path (image 2), and he then loops the club OTT over his right shoulder at the start of the downswing (image 4). This swing pattern will generate an out-to-in clubhead swingpath, and predispose to pulled shots (if the clubface is square to the clubhead path at impact) or pull-sliced shots (if the clubface is open to the clubhead path at impact). Note how steeply the clubshaft decends down towards the ball (image 5) and note that it moves outside the "acceptable corridor" for Jim McLean's "slot swing" due to the fact that the golfer moves his hands too far out (towards the ball-target line) when he starts the downswing with an arm movement, instead of initiating the downswing with a lower body movement that helps to "drop" the club into the slot. This is an extreme example, and most golfers do not have such a large difference between their backswing clubshaft path and their downswing clubshaft path.

Jim McLean divides golfers into three types with respect to their clubshaft movement in the backswing/downswing. 

Type 1 is the standard slot swing.  Jim McLean uses Sergio Garcia as his role model for the standard slot swing.

Standard slot swing - from reference number [1]

Jim McLean states that in the standard slot swing, the club tracks above the address plane in the backswing, and then drops down into a shallower slot in the downswing. The above diagram uses Sergio Garcia's swing as an example. Jim McLean also describes more exaggerated forms of a standard slot swing, where the club's path in the backswing is much steeper (eg. Jim Furyk's and Miller Barber's swings) and where the difference between the steep backswing club path and the shallower downswing club path is greater. 

Type 2 is the reverse slot swing. Jim McLean uses Sam Snead as a role model for his reverse slot swing. 

Reverse slot swing - from reference number [1]

This swing type is the opposite of the standard slot swing in the sense that the club swings under the address plane in the backswing and then loops forward to come down a slightly steeper plane in the downswing. In his book, Jim McLean states-: "starting down, the hands and arms loop well outward to get everything lined up. The clubhead trails the hands, instead of tipping over in front of the body: a classic death move". In other words, although the golfer moves his hands outwards (towards the ball-target line) at the start of the downswing, he doesn't throw his arms/clubshaft too far outwards so that the clubshaft comes down along a too-steep path (as occurs in an OTT move - as demonstrated in the previous photo series). 

Type 3 is the "single-plane" slot swing. Jim McLean uses Tiger Woods as his role model for his "single-plane" slot swing.

"Single-plane" slot swing - from reference number [1]

Jim McLean states that Tiger Woods takes his clubshaft away on the clubshaft's original address plane, and that he then steepens his clubshaft's movement so that the clubshaft becomes parallel to the address plane by the mid-backswing. He then states that Tiger Woods tries to match this same plane shaft position in the mid-downswing. In other words, his clubshaft is roughly in the "same place" somewhere in the "slot corridor" in both the backswing and downswing. Considering the nature of his description, I can see why Jim McLean thinks that Tiger Woods is executing a * "single-plane" swing  - especially if one also considers the associated fact that his clubhead seemingly traces a near-identical circular path in the downswing as the backswing - as viewed from a down-the-line view. 

(* In the next section, I will demonstrate that Tiger Woods actually has a double-plane shift swing, that is similar to Sergio Garcia's double plane shift swing, and that he doesn't have a single-plane swing - by using a different concept of what represents a "plane"). 

In his book, Jim McLean states that he thinks that the reverse slot swing is the most natural way to swing a club, and he likens the motion to a railroad worker swinging a sledgehammer. He writes-: "Because the sledgehammer is heavy, the worker swings the hammer inside, and once he gains momentum, he lifts it up using the big muscles of his shoulders and back. ----- In order to build momentum and really drive that spike into the rail, the man swinging the sledgehammer loops his hands up and over at the start of the downswing.  ----- Although his arms and hands loop out away from him, the head of the sledgehammer stays back. It trails the hands". However, although Jim McLean states that it is the most natural way to swing a golf club, he apparently doesn't promote the reverse slot swing as his best-choice in his golf schools. 

It is also clear that Jim McLean doesn't favor the "single-plane" slot swing. He states-: "The lure of the single-plane is strong. Why make things difficult by changing planes? The answer is that when you flatten your shaft, you turn your club into a whip. By trying to stay perfectly on one plane, it's harder to get that *"fall-in" move that happens when you lead your hit (or throw) with your right elbow". In other words, Jim McLean believes that the standard slot swing is better because it allows the club to "fall-in" and then enter the "slot" during the early downswing. 

Jim McLean is a strong believer in the "fall-in" move, and it is not surprising that he primarily teaches the standard slot swing in his golf school programs. In his book, he states-: "Swinging the club slightly above the plane line and setting the shaft on a steeper backswing plane, then lowering it to a flatter downswing plane, is the easiest way for most golfers to hit quality shots consistently. That's why I most frequently recommend the Slot Swing to my students and why it's so prominently featured in this book". 

What does Jim McLean mean by a club "fall-in" phenomenon?

Jim McLean uses the following diagram to explain the club "fall-in" phenomenon.

Club "falling back" phenomenon - from reference number [1]

The caption for this diagram states-: "It should feel as if the clubshaft and the clubhead are falling behind the body". On page 15, he states-: "Your hands don't retrack on the way back down to the ball. They remain on the same plane they rest on at the top (or get slightly steeper). It's the clubshaft that falls to the lower plane". In other words, Jim McLean seemingly believes that the *hands and clubshaft are not on the same plane,  and he believes that the clubshaft should flip over backwards to a shallower plane while the hands remain on the same plane, or even a steeper plane - presumably due to some unspecified movement at the level of the wrists/hands.

He also writes-: "Its important to realize that the act of swinging "on plane" doesn't mean that your hands, left arm, and shaft work on the same plane at the same time. Although there are some points in your swing where everything matches up, it's incredibly difficult to plane everything perfectly, including the clubhead , the shaft, the hands and the arms".

(* I personally believe that Jim McLean's "fall-in idea" regarding the "planar relationship between the clubshaft and the hands" is totally wrong - and I will provide a detailed explanation to support my opinion in the next section. In that section, I will also demonstrate that it is both easy and bioemechanically natural to keep the left hand and the clubshaft on the same plane at all times if you understand the TGM "flying wedge" concept).

Most of his book is devoted to discussing the standard slot swing's methodology, and a critical part of the methodology is his "ideas" about the biomechanical actions a golfer needs to use to flatten the clubshaft in the downswing, so that it can "fall-in" to the "slot". Jim McLean believes that the critical moves that a golfer needs to use to flatten the clubshaft at the start of the downswing is the combination of a i) left-lateral pelvic shift movement and a ii) dropping of the right elbow towards the right hip at the start of the downswing.   

Regarding the pelvic movement that initiates the downswing, Jim McLean describes it as a lateral move. He states-: Your first move from the top is to shift your lower body laterally towards the target", and he uses the following diagram as a visual aid for his ideas.

Hip slide movement - from reference number [1]

On page 60, he states-: "Almost immediately on finishing your backswing, get your lower body moving towards the target. Lee Trevino always said that he liked to "break my knees towards the target" to start his downswing. That's one good way to capture the correct feel. As you shift your knees forward, moving your weight along with them, allow the triangle formed by your elbows and arms to drop down". 

Jim McLean doesn't explain the biomechanics of how a left-lateral movement of the pelvis can cause the arms/clubshaft to move downwards. He is also extremely vague in terms of providing a rational explanation for the club "falling back" phenomenon. He states-: "If you do it correctly, the clubshaft will be trailing, and, due to the forward motion of your lower body and soft wrist joints, automatically flatten out and drop behind you --- As your arms drop and your lower body moves forward, your clubshaft should flatten. * It shifts onto a lower plane (hopefully) without even having to think about it". 

(* I don't know if this website's visitors find JimMcLean's prose explanation helpful. It is also interesting that Jim McLean uses the phrase "soft wrist joints". It seemingly implies that he believes that soft wrist joints allow the clubshaft to "fall-back" to a lower plane, while the hands remain on the same plane - when the pelvis moves left-laterally. I disagree with Jim McLean's soft wrists concept and I am a great believer in detailed biomechanical/mechanical explanations - I will therefore provide an in-depth explanation of the causal connection between a lower body movement and arm/clubshaft movements in a subsequent section).

 

Re-interpreting the geometry and mechanics and biomechanics of the "slot swing" - my personal explanation:

 

First of all, I think that Jim McLean is mixing-up the concept of a "plane" with the concept of a "path" when it comes to his diagrams showing the three types of slot swing variations. 

If you look at his diagrams, you can see that he is really tracing the path of the peripheral end of the club - clubhead end of the club - in 3-D space in his diagrams. However, the concept of a plane is different to the three-dimensional concept of a path - because a plane is two-dimensional and it must have a baseline. The idea of a plane is best understood when viewing a golfer from a down-the-line perspective, and relating the arm/clubshaft's movements with respect to that plane. The first mention of a plane comes from Ben Hogan, when he introduced his idea of a pane of glass resting on his shoulders.

Pane of glass representing a plane - from reference number [4]

Note that the pane of glass - representing a plane - rests on the ground, and the straight-line base of the glass pane is usually parallel to the ball-target line. In fact, the base of the inclined plane usually sits on the ball-target line if the golfer sets up perfectly square to the ball-target line. The pane of glass is then angled-up relative to the ground, and this gives rise to the concept of an inclined plane.

Homer Kelley is the first person who clearly defined the different inclined planes [5], and he gave them precise definitions.  

Different planes - from reference number [6]

All the inclined planes rest on the ball-target line, and they have different degress of inclination with respect to the ground. 

The hand plane is angled through the hands at address. It usually points at the belt buckle, and passes through the lower back.

The elbow plane is angled through the right elbow (at impact, and often at address). It usually passes through the mid-back. 

The turned shoulder plane is also called the right shoulder plane, and it is angled so that it passes through the right shoulder when the right shoulder is at its end-backswing position.

The squared shoulder plane is angled through the top of the right shoulder at address, and this is where Ben Hogan's glass pane would rest at address. 

Now consider the movements of the hands/clubshaft with respect to these inclined planes. 

Aaron Baddeley, like Tiger Woods, can generate a clubhead arc path in the downswing that follows the same path it followed in the backswing - when viewed from a down-the-line (DTL) perspective.

Aaron Baddeley's clubhead arc as viewed from a DTL view - capture images from his swing video

According to Jim McLean's imprecise definition, Aaron Baddeley could be perceived to have a single-plane swing - because his clubhead is tracing the same path in the downswing as the backswing. 

However, if one considers the positional movements of his hands/clubshaft during his swing, then one will soon discern that Aaron Baddeley has a double plane shift swing. 

Aaron Baddeley's double plane shift swing - capture images from his swing video

Aaron Baddeley's hands/clubshaft is on the hand plane at address. His hands/clubshaft then ascend along a steeper path during the backswing and end up just above the right shoulder plane (TSP) at the end of his backswing. He then drops his hands/clubshaft down to a shallower plane during the downswing, and his hands/clubshaft end up on the elbow plane at impact. He therefore has a double plane shift swing (hand plane => TSP during the backswing, and TSP => elbow plane during the downswing).

How fast does he drop his hands/clubshaft during the downswing?

Consider the following series of downswing images. 

Aaron Baddeley's arm/clubshaft movement during his downswing - capture images from his swing video

In the first image, his left arm is parallel to the ground (and this position is defined as the end of the early downswing). Note that his clubshaft and the back of the flat left wrist/hand is just below the TSP and just above the elbow plane - along an inclined plane that is approximately 50% of the angular difference between the TSP and the elbow plane. Note that his clubshaft (and the back of his flat left wrist/hand) continues to shallow-out during the mid-downswing (as it passes through the "slot") and it reaches the elbow plane by image 3. 

It is very important to note that during his clubshaft's shallowing action, the clubshaft and back of his flat left wrist/hand always remain on the same plane - there is no "fall-back" phenomenon as described by Jim McLean, where the clubshaft falls-back to a shallower plane while the hands remain on the same, or a steeper, plane.

I believe that the club "fall-back" phenomenon  (as described by Jim McLean) should never happen in a good golfer's downswing - and I will provide a detailed explanation to support my opinion later in this section.

Let's first consider Tiger Woods and Sergio Garcia's swings from this planar perspective.

Starting with Tiger Woods swing - http://www.youtube.com/watch?v=W8N-N4FEoMY&NR=1

Tiger Woods' plane shifts - capture images from his swing video

Image 1 shows Tiger Woods at address - note that his clubshaft in on the hand plane (red line).

Image 2 shows Tiger Woods at the end of the mid-backswing - when his left arm is parallel to the ground. Note that his hands and clubshaft are on a steeper plane. Many golfers would imagine that his clubshaft is parallel to the hand plane (clubshaft-at-address plane). However, that 's not true - note that the butt end of his clubshaft points at the ball, and that means that he is on-plane (per Homer Kelley's definition of an on-plane swing - where the end of the club that is nearest the ground always points at the base of the inclined plane). Note that the back of his flat left wrist/hand is on the same plane as the clubshaft - because Tiger Woods maintains an anatomically flat left wrist throughout his backswing and downswing. 

Image 3 shows Tiger Woods at his end-backswing position. Note that his flat left wrist/hand and clubshaft are just above the TSP (blue line).

Image 4 shows Tiger Woods at the end of the early downswing (when his left arm is parallel to the ground). Note that his flat left wrist/hand and clubshaft are on the same plane - that plane is intermediate in steepness between the TSP and the elbow plane (yellow line). Note that his hands are roughly in the same position in image 2 (backswing) and image 4 (downswing) - opposite his right mid-chest. That explains why Jim McLean thinks of Tiger Woods as having a single-plane swing - his hand arc in the downswing follows the same path it followed in the backswing (as seen from a DTL view). Note that the butt end of his club points at the ball-target line, which means that his clubshaft is on-plane.

Image 5 shows Tiger Woods at impact - his clubshaft is on the elbow plane.

Tiger Woods has a similar swing to Aaron Baddeley - it's a double plane shift swing (hand plane => TSP in the backswing; TSP => elbow plane in the downswing) where the flat left wrist/hand and the clubshaft shallow-out slowly/gradually/progessively during the early-mid downswing as he shifts planes from the TSP to the elbow plane. Note that there is no club "fall-back" phenomenon in his swing - see next series of images.

Tiger Woods shallowing-out his clubshaft and entering the "slot" - capture images from his swing video

Image 1 shows Tiger Woods at the end-backswing position. Images 2, 3 and 4 show how Tiger Woods shallows out his clubshaft in the early downswing. Most importantly, note that the back of his flat left wrist/hand remains perfectly straight-in-line with his clubshaft during this clubshaft-shallowing action - which means that his flat left wrist/hand remains on the same plane as the clubshaft as he shallows-out the clubshaft. There is no club "fall-back" phenomenon - as described by JimMcLean.

Now consider Sergio Garcia's swing - http://www.youtube.com/watch?v=2bDGTEvnPjU

Sergio Garcia's plane shifts - capture images from his swing video

Image 1 shows Sergio Garcia with his hands and clubshaft on the hand plane at address (red line).  

Image 2 shows Sergio Garcia at the end of the mid-backswing when his left arm is parallel to the ground. Note that his hands/clubshaft are on a steeper plane - intermediate between the TSP and the hand plane.

Image 3 shows Sergio Garcia at the end-backswing position - his hands/clubshaft are just below the TSP (blue line).

Image 4 shows Sergio at the end of the early downswing - when his left arm is parallel to the ground. Note that the back of his flat left wrist/hand and clubshaft have dropped down to the hand plane. Note that his hands are opposite his right lower arm and not opposite his right chest (like Tiger Woods and Aaron Baddeley). Sergio Garcia drops his hands/clubshaft steeply downwards in the early downswing. In other words, his hands/clubshaft have dropped almost vertically down to a shallower plane in the early downswing - before he pulls his hands and clubshaft outwards-forwards in the direction of the ball. From that position, he is going to slide his hands/clubshaft down the inclined plane (hand plane) so that his clubshaft is on the hand plane at impact (image 5).

Sergio Garcia has a double-plane shift swing - hand plane => TSP in the backswing; TSP => hand plane in the downswing.

Consider Sergio Garcia's hand/clubshaft movements in the early downswing. 

Sergio Garcia shallowing-out his clubshaft in the early downswing - capture images from his swing video

The sequence of five photos shows Sergio Garcia shallowing-out his clubshaft in the early downswing. Most importantly, note that he maintains an anatomically flat left wrist/hand throughout this action, and that his flat left wrist is always on the same plane as his clubshaft as he shallows-out his clubshaft from the TSP to the hand plane (during the early downswing). There is no club "fall-back" phenomenon - as described by JimMcLean.

In his book [1], Jim McLean used the analogy of a baseball player to describe his idea of a club "fall-back" phenomenon.

Baseball swing analogy - from reference number [1]

The above photo shows how a baseball player's bat "falls back" when he starts the downswing. 

Jim McLean states in his book-: "Over the years, I've found it helpful to relate the downswing and the impact to something with which the student is more familiar. For most people, that's swinging a baseball bat. ---- In both swings, the "stick" flattens (or lowers) at the start of the forward-swing."

However, I think that there is a huge difference between swinging a baseball bat compared to swinging a golf club. Note the positional alignment of the baseball player's left arm/hand/clubshaft at the start of his downswing action. His left elbow is bent, and his left wrist is cupped/scooped due to a bent left wrist, and that allows the baseball player to have his clubshaft more vertically aligned relative to the left arm. From that out-of-alignment position (clubshaft not aligned straight-in-line relative to the back of the left forearm) the club will obviously have to "fall-back" in the early downswing so that the left arm and clubshaft can be better aligned during the mid-downswing swing action. However, that club "fall-back" phenomenon doesn't happen in a good golfer's downswing action. Note that the golfer (in the diagram) has his clubshaft aligned straight-in-plane with his flat left wrist/left forearm at the start of the downswing. That straight-line planar relationship must be maintained during the early downswing and mid-downswing - while the clubshaft shallows-out during its passage to, and through, the "slot box". 

To better understand the biomechanics/mechanics of this phenomenon, a golfer needs to understand *Homer Kelley's left arm flying wedge and right forearm flying wedge concept [5].

( * I described, and demonstrated, the flying wedge concept in my How to Move the Arms, Wrists and Hands in the Golf Swing review paper, and the accompanying swing video lesson).

If a golfer understands the flying wedge concept and the power package concept, then it becomes much easier for a golfer to understand how to move the arms/clubshaft in the early downswing.

At the end-backswing position, a golfer must have "correctly" assembled the power package and also "correctly" aligned the right forearm flying wedge with respect to the left arm flying wedge. The following photograph demonstrates the "correct" alignments.

Tiger Woods and Adam Scott at the end-backswing - capture images from their swing video [7]

The left arm flying wedge is colored in yellow - and it consists of the wedge-like structure represented by the straight left arm and the clubshaft which is in-plane with the left arm (note the anatomically flat left wrist/hand) but at a ~90 degree angle relative to the left arm.

The right forearm flying wedge consist of the right forearm and the bent right wrist and it is colored in red. Note that the right forearm is at an angle of roughly 90 degrees relative to the left arm flying wedge. At the end-backswing position, the right forearm flying wedge supports the left arm flying wedge - like an airplane's wing strut supporting the wing of a small Cessna airplane. That is the critical relationship, and the fact that the right forearm is vertical to the ground is not of real importance. The angle of the right forearm relative to the ground is greatly affected by the angle of the straight left arm relative to the ground.

The green colored area is the right upper arm and the right shoulder, and it connects the right forearm flying wedge to the torso. The power package consists of the green colored area, red colored area and the yellow colored area. Note that the right elbow is bent at roughly a 90 degree angle. 

During the early downswing, the alignment relationships within the power package must remain intact.

Consider Ben Hogan's early-mid downswing action - when he drops his clubshaft into the "slot" - http://www.youtube.com/watch?v=LJdChWnxDvU

Ben Hogan dropping his clubshaft into the "slot" - capture images from his swing video

This photo series shows Ben Hogan dropping his clubshaft into the "slot". Note that I have used the same colors to represent the left arm flying wedge (yellow) and right forearm flying wedge (red) in this photo.

Note how Ben Hogan maintains the alignment relationships of the power package intact during the early downswing as he drops his clubshaft into the "slot". Note that the left arm flying wedge remains intact - the peripheral end of the left arm and clubshaft are always in a straight-line planar relationship (moving in the same plane of motion) and the ~90 degree angle between the left arm and the clubshaft is maintained unchanged. Note that the right forearm flying wedge maintains a roughly 90 degree relationship to the left arm flying wedge. Note that the right elbow remains bent at roughly 90 degrees. It is the "correct" movement of the intact power package that causes the club to "correctly" drop into the "slot". In the swing video, Ben Hogan states that the butt end of his club is directed straight at the ball. In other words, in the early downswing, a golfer needs to move the intact power package in such a manner that the club is directed downplane in the general direction of the ball. When keeping the power package intact during the club "slotting" action, Jim McLean's idea of "soft wrists" becomes meaningless - because one actually needs firm wrists to keep the left arm flying wedge intact (via maintaining a constantly flat left wrist - either * anatomically flat or geometrically flat) and the right forearm flying wedge intact (by ensuring that the degree of right wrist bend remains unchanged). There should be no movement at wrist level during the process of lowering the intact power package down towards waist level (down towards the delivery position) during the club slotting action.

(* I discussed the difference between an anatomically flat left wrist and a geometrically flat left wrist in my Left Arm Swinging, Right Arm Swinging, and Hitting review paper, and also in the accompanying swing video lesson).

Which biomechanical factors are primarily responsible for the movement of the intact power package?

Jim McLean implies in his book [1] that the primary biomechanical factor that causes the arms/clubshaft to drop into the "slot" is a left-lateral movement of the pelvis? That is biomechanically incorrect - it only has a secondary/suuplementary effect (which I will describe in the next section where I describe pelvic movements). There is no direct biomechanical mechanism that directly links the pelvis to the power package. There are two primary biomechanical factors that primarily affect the movement of the power package in the early downswing - i) the 3-D movement of the shoulder sockets in space and ii) the independent movement of the humeral heads within their respective shoulder sockets. 

The power package is connected to the torso via the shoulder sockets, and therefore the 3-D movement of the shoulder sockets in space affects the directional movement of the intact power package. Note that Ben Hogan's shoulder sockets move in approximately a horizontal plane of motion in the early downswing, and their horizontal movement causes the intact power package to move more-or-less horizontally (outwards towards the ball-target line). While this is happening, the intact power package is also moving downwards in the direction of the ground - and that is due to an independent movement of the right upper arm in the right shoulder socket. In other words, the right upper arm (humerus) is being adducted towards the right side of the upper-mid torso while both upper arms are being pulled outward-forwards by their respective shoulder sockets. The 3-D movement of the intact power package in space is therefore primarily dependent on the speed of adduction of the right upper arm downwards (so that the right elbow moves in the direction of the right hip) relative to the speed of movement of the shoulder sockets in space. Different golfers have individual variations in the speed/direction of movement of these two major biomechanical actions that are primarily responsible for moving the intact power package, and therefore the clubshaft, into the "slot box". Sergio Garcia differs from Tiger Woods because his down-component (due to active adduction of the right upper arm) occurs much faster than the outwards component (due to active rotation of the shoulder sockets) per unit time - during the early downswing. That fact causes Sergio Garcia to drop his hands/clubshaft from the TSP to the hand plane at the start of the downswing, while Tiger Woods' hands/clubshaft drops more gradually from the TSP to the elbow plane during the early-mid downswing. 

Another factor that affects the relative speed of movement of the down component of the intact power package compared to the relative speed of movement of the outward component is the position of the hands at the end-backswing position. 

Consider Jim Furyk's swing -  http://www.youtube.com/watch?v=DFDRebJy8ac

       

3-D movement of Jim Furyk's power package in the early downswing - capture images from his swing video

Note that Jim Furyk has a very upright backswing arm action that gets his hands high above his neck by the end of his backswing - image 1. However, note that his right forearm flying wedge is correctly aligned relative to his left arm flying wedge at his end-backswing position. Note that his right forearm is not vertical to the ground - like Tiger Woods and Adam Scott - because the left arm has a different angle relative to the ground.

Note how much Jim Furyk's hands drop vertically downwards in the direction of his right hip in the early downswing (images 2, 3 and 4) and that is due to the fact that he is actively adducting his right upper arm towards the right side of his torso. The right arm's adduction movement is primarily due to active muscular contraction of peri-scapular (shoulder girdle) muscles and only partly due to gravity. From a biomechanical perspective, the vertical component of the 3-D movement of the intact power package is not  primarily related to the fact that he is moving his lower body (pelvis) at the same time. 

Note how Jim Furyk maintains the "correct" left arm flying wedge relationship during the early downswing - the clubshaft and left arm have a straight-line planar relationship due to the fact that he maintains an anatomically flat left wrist throughout the early/mid downswing. There is no club "fall-back" phenomenon (where the clubshaft falls down to a lower plane while the hands remain on a steeper plane) as described by Jim McLean in his book [1] - the flat left wrist/hand and clubshaft are moving to a shallower plane at the same rate of angular velocity. If the clubshaft shallowed-out faster than the flat left wrist/hand then the left wrist would have to become significantly arched/bowed in the early downswing, and that phenomenon doesn't happen in a good golfer's swing. Jim Furyk shallows-out the clubshaft in the early downswing by lowering the entire power package as an intact unit - the intact power package moves downwards so that the right elbow can eventually reach the approximate position of the right hip area.

If a beginner golfer understands how to assemble the power package correctly by his end-backswing position, then he must think of how he is going to bring his intact power package down to waist level by simultaneously blending two motions. The one motion that he needs to achieve when he starts the downswing is the vertical downward motion of the intact power package that is due to an active adduction of the right upper arm, so that the right elbow can move in the direction of the right hip area. The second motion that he needs to simultaneously achieve is the outward motion of the intact power package that is due to the 3-D motion of the shoulder sockets in space - and that motion is is secondary to the rotation of the upper torso.

What causes the upper torso to rotate at the start of the downswing?  The answer depends on whether the golfer is a left-arm swinger (who uses an active pivot-drive action to power the swing) or a right-arm swinger (who uses the right upper limb to power the swing and who often uses a reactive pivot action). Most professional golfers are left-arm swingers and they use an active pivot action to power their swing. In an active pivot action, the active pivot action should start from the bottom-up - the lower body should move first and the upper body should move secondarily. The movement of the lower body has a significant influence on the movement of the upper body - and I will describe this "influence" later in this review paper. A *right arm swinger starts the downswing by actively driving the right shoulder downplane while simultaneously actively adducting the right upper arm towards the right side of the torso. The lower body pivots reactively/secondarily in response to the upper body's active motions.

(* I have described the biomechanical differences between left arm swinging and right arm swinging in great detail in my Left Arm Swinging, Right Arm Swinging and Hitting review paper).

Executing a "slot swing" - a recommended swing methodology:

 

In the second half of his book, Jim McLean discusses his methodology of executing his "slot swing". His description is mainly focused on the standard slot swing, where the clubhead path is steeper in the backswing than the downswing. I will contrast some of his recommendations with my own personal approach, which is not based on the clubhead path pattern (eg. standard slot swing versus single-plane slot swing) but based on biomechanically natural movements that allow a golfer to keep the clubshaft on-plane during both the backswing and downswing.

I believe in the idea of a simplified golf swing, where the arms/hands/clubshaft follow roughly the same path in the downswing as the backswing. I have described the methodology in great detail in my How to Move the Arms, Wrists and Hands in the Golf Swing review paper. I will only discuss the general principles in this review paper.

I believe that a golfer should first think of how best to assemble his power package at the end-backswing position. From my perspective, a golfer first needs to decide where his hands should end up at the end-backswing position. I prefer having the hands near (opposite or behind) the right shoulder at the end-backswing position, so that the left arm will lie across the shoulder turn angle.

Desired end-backswing position - capture image from the author's swing video lesson

Starting with image 1. The red dotted line represents the most desirable position for the left arm angle at the end-backswing position - it directly crosses over the right shoulder socket joint. Tiger Woods and Sergio Garcia have their left arm at that angle at their end-backswing position (see previous photos). The blue dotted line represents a slightly steeper left arm angle, which is also perfectly acceptable. Adam Scott and Aaron Baddeley have their left arm at that angle at their end-backswing position (see previous photos). The yellow dotted line is too steep (see Jim Furyk's swing photos previously presented) and I suggest that golfers avoid having their left arm at that steep angle at their end-backswing position. It requires a large compensatory move to shallow-out the clubshaft from that "high-hands" position. 

Note the position of the right hand at the end-backswing position. It is behind and slightly higher than the right shoulder. Note that the clubshaft is in the same plane as the straight left arm (represented by the red dotted line) and that requires that the golfer have a flat (either anatomically flat or geometrically flat) left wrist at the end-backswing position. Note that the right forearm flying wedge is roughly at right angles to the left arm flying wedge. Note that the right forearm is vertical to the ground, and that is only due to the fact that the left arm (red dotted line) has that specific angle relative to the ground. If a golfer has his left arm at a slightly steeper angle (blue dotted line) then the right forearm flying wedge would have to be tilted more forward, and that would cause the right forearm to be angled more forward (closer to being parallel to the spine angle). 

Image 2 shows the end-backswing position for golfers who lack the flexibility to get their hands behind the right shoulder. The hands will end up opposite, or even slightly in front of the right shoulder, by the end of their backswing. Note that the right forearm flying wedge (yellow dotted line) is still at the "correct" angle relative to the left arm flying wedge (red dotted line). 

How should a golfer move the arms/clubshaft to get to that desired end-backswing position?

I described a biomechanically natural method in my How to Move the Arms, Wrists and Hands in the Golf Swing review paper. That method also allows a golfer to keep the clubshaft on-plane throughout the entire backswing. The technique uses the right forearm takeaway, rather than the one-piece takeaway. However, it is also perfectly acceptable to use the one-piece takeaway, because it will also allow a golfer to get to the same "correct" end-backswing position (as demonstrated in image 1). Both Tiger Woods and Adam Scott use the one-piece takeaway. 

I prefer the biomechanical simplicity and biomechanical logic that underlies the right forearm takeaway, and I think that it allows a golfer to more easily keep the clubshaft on-plane throughout the backswing. 

Stuart Appleby is a perfect role model for golfers who want to use the right forearm takeaway - http://www.youtube.com/watch?v=_jqJ9R2LypY&NR=1

Stuart Appleby's backswing action - capture images from his swing video

I have highlighted the right arm/forearm in red, because it allows a reader to concentrate his visual attention on the movement of the right arm/forearm in space. 

Note that Stuart Appleby keeps his clubshaft on-plane throughout the backswing and that he ends up with his left arm at the "desired" angle at his end-backswing position (image 5) - the left arm lies across the shoulder turn angle. Note that his left arm flying wedge is intact - left arm and clubshaft are on the same plane - and note that he has an anatomically flat left wrist. Note that his right forearm flying wedge has the "correct" relationship to the left arm flying wedge. 

Finally, note that Stuart Appleby has a reverse-K position at his end-backswing position (image 5).  

In his book, Jim McLean spends many pages describing how a golfer should move the arms/club in the backswing, but he has virtually nothing to say about the importance of acquiring a reverse-K position at the end-backswing position. I think that it is critically important that a golfer learn how to execute a "correct" backswing pivot action that will allow him to acquire a reverse-K posture at the end-backswing position. 

Brady Riggs describes the "correct" backswing pivot action in this video lesson - http://www.youtube.com/watch?v=WvOr5nNqYEw

Note how Brady Riggs "creates space" under his right shoulder during the backswing. Creating that "space" is essential because it creates a "space" for the power package to descend into when the golfer "slots" the clubshaft in the early downswing.

Consider three golfers' end-backswing positions.

End-backswing posture of three golfers

The golfer (Ben Hogan) in image 3 demonstrates the reverse-K posture - yellow line and red lines together represent a "reverse K" image.

The golfer (Jamie Sadlowski) in image 2 also has a reverse-K posture - note that he has also created "space" under the right shoulder.  

The golfer (Jason Zuback) in image 1 has a reverse-pivoting posture (often seen in S&T golfers) and there is no "space" under the right shoulder. 

I have described the "correct" backswing pivot action required to create a reverse-K posture at the end of the backswing in my The Backswing and Downswing Pivot Movements: Their Critical Role in the Golf Swing review paper.

If a golfer gets to the "correct" end-backswing position, then how should he start the downswing if he wants to "correctly" slot his clubshaft? 

JimMcLean stated in his book [1] that a golfer should start the downswing with a lateral movement of the pelvis towards the target, and he recommended that a golfer break both knees inwards in the direction of the target. I think that it is a terrible idea to think of breaking-in the right knee at the start of the downswing, because I think that it promotes a left-lateral pelvic slide motion rather than a pelvic rotational motion. If a beginner golfer slides the pelvis towards the target as his primary swing thought, then it will likely result in an excessive pelvic slide action.

Oliver Heuler  demonstrating a pelvic over-slide motion - from reference number [8]

Note that the outer border of his left pelvis is outside the left foot (red-arrow). That represents a pelvic over-slide action, and it causes the spine and head to move too far left-laterally. Those biomechanical actions will cause the hands to get too far forward of the ball at impact, and the clubshaft will have excessive forward lean +/- an incomplete release => weak pushed/push-sliced shots.

I think that a golfer should think of the pelvic motion as being a rotational motion, rather than a sliding motion, and the pelvic rotation should start immediately at the start of the downswing. I believe that Hogan's description of the "correct" pelvic motion is still the best advice - and he demonstrated that pelvic motion using the following diagram in his book [9]. 

Hogan's "elastic band" idea - from reference number [9]

Ben Hogan stated that a golfer should think of an elastic band stretching from the front of his left pelvis to an attachment point on a wall behind the golfer, where the attachment point is directly behind the left hip. In the backswing, the elastic band will become stretched when the left pelvis moves forward (towards the ball-target line). Then the elastic band will snap back at the start of the downswing thus causing the left pelvis to be pulled back towards the tush line. That downswing pelvic motion is a rotation of the left pelvis back towards the tush line, and it is not primarily a left-lateral pelvic slide action. 

I think that the golfer who best demonstrates this Hogan-style pelvic motion is Jamie Sadlowski - the current (2008/9) world long-drive champion. His pelvic motion is a "pure" rotational motion, and there is no left-lateral pelvic slide action at the start of his downswing. 

First consider this cross-sectional diagram of the human pelvis, so that you can better understand his pelvic motion in the next composite photo showing Jamie Sadlowski's backswing/downswing action.

Diagram showing a cross-sectional view of the the pelvis at the level of the hip joints

Now consider Jamie Sadlowski's backswing/downswing pelvic motion (where I have combined the same diagram with photos of Jamie Sadlowski during his swing action).

Jamie Sadlowski's pelvic movements during the backswing and downswing - capture images from his swing video [10]

Image 1 shows Jamie Sadlowski at address - his pelvis is square to the ball-target line (parallel to the ball-target line) and his pelvis is centralised between his feet.

Image 2 shows Jamie Sadlowski at his end-backswing position. Note that there has been no swaying of the pelvis to the right. He has simply pulled his right buttocks back away from the ball-target line in the direction of the tush line (yellow dotted line) and during this pivot action the left buttocks moves leftwards as well as backwards (towards the tush line) - as demonstrated by Brady Riggs in his swing video lesson. 

Image 3 shows Jamie Sadlowski's first pelvic motion at the start of the downswing. Note that he is performing Hogan's "elastic band" pelvic action - he is pulling his left pelvis back towards the tush line (see red curved arrow in diagram number 3). Note that there is no breaking-in of the right knee and there is no left-lateral swaying of the pelvis. 

Image 4 shows Jamie Sadlowski at the end of his early downswing (when his left arm is parallel to the ground). Note that his pelvis is square - parallel to the ball-target line (as at address).  Note that his pelvis is still centralised between his feet - there has been no left lateral pelvic shift movement. Note that his right knee has still not broken-in, and it is unchanged compared to his end-backswing position. This represents the hip-squaring phase of his downswing, and he has the characteristic Sam Snead "sit-down" look - with both knees bowed slightly outwards.

Image 5 shows Jamie Sadlowski at impact. Note that his pelvis is still centralised between his feet - there has been no left-lateral shift of his pelvis towards the target during his entire downswing. Note that his pelvis is open to the target. Note that his right knee has finally broken-in during the late downswing, and that biomechanical phenomenon is secondary to the fact that his pelvis has rotated to an open position and also due to the fact that his right leg is now significantly unweighted. 

Although Jamie Sadlowski has no left-lateral shift of his pelvis, he has no problem lowering his intact power package downwards and shallowing-out the clubshaft during his early downswing. It is a biomechanically unfounded myth to believe that a left-lateral pelvic shift action is mandatory to shallow-out the clubshaft during the early downswing's "slotting" action.

Here is another example of a different pelvic action that also doesn't involve a left-lateral pelvic slide action during the early downswing.

VJ Trolio wrote a book called "The Final Missing Piece of Ben Hogan's Secret Puzzle" [11].

He believes that the pelvis should be shuttled leftwards during the late backswing, so that most of the body weight is over the left leg at the end-backswing position.

He explains his "belief" in the following swing video presentation - http://www.youtube.com/watch?v=cov8R5Axt4k

Here is a photo comparison of Jamie Sadlowski's and VJ Trolio's end-backswing positions.

Jamie Sadlowski's and VJ Trolio's pelvic position at the their end-backswing position

I have drawn red arrowed lines from the outer borders of their pelvis vertically downwards. One can see that Jamie Sadlowski's pelvis remains centered between his feet, while VJ Trolio's pelvis is shifted well to the left, so that he has most of his weight over the left leg at the end-backswing position. VJ Trolio believes that this is the optimum pelvic position because he believes that it allows a golfer to pivot-rotate the pelvis very efficiently during the downswing without any need for any preliminary left-lateral pelvic shift motion. 

Whether one agrees with his swing philosophy (or not), one has to readily admit that he has a superb swing and that he can readily "slot" his clubshaft in the early downswing.

See - http://www.youtube.com/watch?v=SM8zE1s5qf4

Here are a series of photographic images from his book [11].

VJ Trolio's backswing/downswing swing action - from reference number [11]

The first 4 images shows VJ Trolio's backswing action. Note how he moves his pelvis left-laterally in the late backswing, so that he is primarily weighted over the left leg at the end-backswing position (image 4). 

Note, in the early downswing (image 5), how efficiently he drops his intact power package into the "space" that he has created under his right shoulder during the backswing. During this early downswing action, he is pivot-rotating around his braced left leg and there is no preliminary left-lateral pelvic shift of his pelvis during the early downswing. He is simply pulling his left pelvis back towards the tush line (as Hogan explained in his "elastic band" diagram).

Note how he adducts his right upper arm towards his right side during the early downswing (image 5) and this biomechanical action directs the right elbow towards his right hip area. While this is happening, he is simultaneously rotating his upper torso around his rightwards-tilted spine. As I previously explained, the degree of planar shift of the clubshaft per unit time (degree of clubshaft shallowing per unit time) in the early downswing depends on the relative speed of the i) downward adduction movement of the right upper arm compared to the relative speed of  ii) upper torso rotation per unit time. Each individual golfer has a different pattern of time-coordinating these two biomechanical motions which are primarily responsible for "slotting" the club in the early downswing.

Now, although I have shown that it is possible to "slot" the club in the early downswing without any preliminary left-lateral pelvic shift motion, it is very likely that most good golfers will have a small degree of left-lateral pelvic motion - often referred to as a "hip bump" - at the start of the downswing. The primary purpose of the "hip bump" maneuver is simply to replant weight on the left foot at the start of the downswing, so that one can more efficiently perform the "left hip clearing action" against the resistance of a braced left leg.

Consider Stuart Appleby's swing - http://www.youtube.com/watch?v=_jqJ9R2LypY&NR=1

 

Stuart Appleby's backswing - capture images from his swing video

Stuart Appleby's downswing - capture images from his swing video

Image 1 in the downswing series shows Stuart Appleby starting the downswing with a "hip bump" to the left. That left-lateral movement of the pelvis is due to a replanting of weight on the left foot, which requires a movement of the left knee leftwards so that the left knee becomes vertically-oriented over the left foot. During this "hip bump" action he is also simultaneously rotating his pelvis to a square position by pulling his left buttocks rearwards in the direction of the tush line. In other words, the pelvic motion is primarily a rotary movement (left hip clearing action), but the entire pelvis moves slightly left-laterally during this "left hip clearing" action, because his left pelvis was significantly unweighted at the end-backswing position. 

Note how his left leg becomes increasingly braced/straightened throughout the downswing, and note that his left hip is vertically-oriented directly over his left foot at impact. Having a straight left leg at impact (where the left hip joint is directly over the left foot) is a common feature of modern day professional golfers (eg. Tiger Woods) and to get to that position, there must be small amount of left-lateral pelvic motion, which occurs while the golfer is performing a Ben Hogan "elastic band" type of rotary pelvic action. Can that small amount of left-lateral pelvic action at the start of the downswing cause the clubshaft to shallow-out? I know of no biomechanical mechanism that can directly cause that phenomenon, other than the fact that this small degree of left-lateral pelvic motion increases the degree of rightwards spinal tilt by moving the lower lumbar spine leftwards, while the head is kept stationary. The biomechanical process of acquiring that increased degree of rightwards spinal tilt (due to the left-lateral pelvic motion) is called secondary axis tilt, and when a golfer acquires secondary axis tilt in the early downswing, it causes the right shoulder to move downwards in the direction of the ground. The right shoulder's downplane motion causes the entire power package to move downwards in the direction of the ground. While this is happening, the golfer is also actively adducting the right upper arm and rotating the upper torso (rotating the shoulder sockets). I think that it is impossible to clearly separate-out these different biomechanical actions which are occurring simultaneously, and calculate how much of the left hand/clubshaft shallowing-out action is due to the left-lateral pelvic motion. I think that it is probably a significant contributing factor. 

Look at image 3 in both the backswing and downswing series - note that his clubshaft is just above the white line in the backswing and just below the white line in the downswing (in the DTL views). This difference represents a "clubshaft shallowing-out" phenomenon. Also, note three biomechanical differences in image 3 of the downswing compared to image 3 of the backswing - i) note that the right upper arm is being actively adducted towards the right side of the torso in the downswing, while it is slightly separated from the right side of his torso during the backswing; ii) note that the right hip has moved away from the white line in the downswing while it abuts the white line in the backswing; iii) note that the right shoulder is much lower in the downswing than at the same stage of the backswing. I believe that biomechanical event iii) is partly due to biomechanical event ii) and that the synergistic combination of the two biomechanical events -  i) right arm adduction and iii) right shoulder moving downplane - is causally responsible for his clubshaft shallowing-out during his clubshaft "slotting" action (via their direct biomechanical "effect" on the 3-D movement of the intact power package). 

Understanding the biomechanics involved in "slotting" the club is particularly important for right arm swingers who use a reactive pivot action. A right arm swinger starts the downswing with an active movement of the power package, while allowing the pivot action to be secondarily reactive to the upper body/arm movements. I described the biomechanical methodology in great detail in my Left Arm Swinging, Right Arm Swinging and Hitting review paper. A key point that a right arm swinger needs to understand is that he must start the downswing with two biomechanical actions that have to occur simultaneously - i) an active downplane thrust movement of the right shoulder and ii) an active adduction movement of the right upper arm. Those two biomechanical actions will ensure that the intact power package and clubshaft is "correctly" driven into the space under the right shoulder, so that the clubshaft can be "correctly" slotted (as explained in great detail in this review paper).  

I previously mentioned that Stuart Appleby is a perfect role model for golfers who want to learn how to "correctly" slot their swing. Why? The reason is that his swing actions are very simple, and he moves his hands along the same path in the downswing as the backswing - see above DTL photos. The advantage of this simple technique is that is easier to keep the clubshaft on-plane during both the backswing and downswing. In his book [1], Jim McLean has virtually nothing to say about keeping the clubshaft on-plane during the clubshaft slotting maneuver. I am a great believer in the advantage of keeping the clubshaft on-plane during the downswing, so that one can generate an in-to-square-to-in clubhead path that is perfectly symmetrical with respect to the ball-target line. In my Swingplane review paper, I stated that a golfer needs to accomplish two goals during the downswing - i) slot the club so that it moves down towards impact along a progressively shallower planar path and ii) keep the clubshaft on-plane throughout the entire downswing. A golfer needs to learn how to keep the clubshaft on-plane during the entire downswing, and I believe that it is the controlled 3-D motion of the right forearm/hand in space that directs the 3-D motion of the clubshaft and keeps the clubshaft on-plane.

Consider how Martin Hall keeps his clubshaft on-plane during both the backswing and downswing in this video presentation of the Smartstick device.

http://smartstickgolf.com/why-it-works/plane

When watching the video presentation, note that Martin Hall keeps the clubshaft on-plane during both the backswing and downswing (and followthrough). Note how his hands move along the same basic hand arc path during both the backswing and downswing. 

Martin Hall tracing a straight plane line in the downswing - capture images from the swing video

Note how *Martin Hall keeps the butt end of the club pointing at the ball-target line (see green laserlight spot between the blue lines) while he drops the clubshaft through the "slot" in the early-mid downswing.

(* The video presentation is done in slow motion for demonstration purposes and it doesn't represent a "real life" swing - however, it does demonstrate the importance of learning how to keep the clubshaft on-plane while slotting the clubshaft)

To learn how to keep the clubshaft on-plane, one has to "educate one's hands" so that they can keep the clubshaft on-plane. In fact, one really has to learn how to "correctly" move the right forearm/hand in space to keep the clubshaft on-plane throughout the swing, and one has to learn how to use the right forearm/PP#3 to trace a straight plane line (SPL). I have described this procedure in great detail in my How to Move the Arms, Wrists, and Hands in the Golf Swing review paper (and I demonstrated the procedure in the accompanying swing video lesson); and I have also discussed this issue comprehensively in my How to Hit the Ball Straight - The Essential Elements review paper. A golfer will greatly benefit if he can keep his clubshaft on-plane when he is performing his personal version of a "slot swing" because it makes it more likely that he can generate a clubhead arc that is perfectly symmetrical with respect to the ball-target line.

 

Conclusion:

 

In this review paper, I have briefly described Jim McLean's approach to performing a slot swing. I have also described my personal approach, which is primarily based on some of Homer Kelley's TGM concepts [5]. I personally think that TGM concepts - like the flying wedges, and the power package assembly/loading/delivery mechanisms - are useful mental concepts, that allow a golfer to better mentally visualize the "correct" execution of the golf swing mechanics that form the basis of the club slotting procedure. I have also used my significant knowledge of human biomechanics to discuss the underlying biomechanics that are primarily responsible for slotting a club. I personally believe that a greater understanding of golf swing mechanics/biomechanics should help a golfer improve his golf swing slotting technique, and I hope that this review paper provides all golfers, who read this review paper, with enough golf instructional information that they can successfully accomplish that goal. 

 

Jeff Mann. 

December 2009.

 

References:

 

1. The Slot Swing. Jim McLean.

 

2. Kevin Na swing video.

http://www.youtube.com/watch?v=E0EKksPTyk0

 

3. Slice the Slice Out of Your Swing!

http://video.google.com/videoplay?docid=-4312420981818984859&hl=en

 

4. The Fundamentals of Hogan. David Leadbetter.

 

5.  The Golfing Machine. Homer Kelley.

 

6.  Plane photograph. Created by Brian Manzella.

http://homepage.mac.com/brianmanzella/.Pictures/MATRIXPLANES1.jpg

 

7. Tiger Woods and Adam Scott swing video.

Available at http://www.youtube.com/watch?v=ZecViQxUwss

 

8. Slice video.  Oliver Heuler.

http://golfforum.de/startseite/slice

The text on that website page is in German, but the video is in English.

 

9. Ben Hogan's Five Lessons. Ben Hogan.

 

10. Jamie Sadlowski's driver swing video.

http://www.youtube.com/watch?v=EZ0dNIP-yoU

 

11. The Final Missing Piece of Ben Hogan's Secret Puzzle. VJ Trolio.