Everything You Always Wanted to Know About Shallowing But Were Afraid to Ask.

Before we proceed to the Part 4. of the series devoted to the lengthening of the flat spot we need to explain the process of decreasing the angle of downswing path which is also known as shallowing of the path or club or shaft in macroscale. This is, by the way, a very hot topic in the golf instruction nowadays.

The golf swing action takes place in a 3-D spacial world. It means that -- taking into account the ball lies on the ground -- golfers need to use both vertically as well as horizontally oriented movements. Since the goal is to hit the ball our mind partially associates it with a "chopping wood with an axe" up and down pure vertical motion (power element) with a vivid help from gravity. Unfortunately, it is not so easy. Hitting onto the ball is not enough to play golf. The goal is to hit the ball the way it goes to the West (assuming we face North when taking stance). This brings a "pushing down the line" from the East to the West pure horizontal motion (direction element) into play (vector of which does not act always in accordance with the gravity). The inavoidable mixture of both elements determine the characteristics of the downswing path of the club of course together also with the backswing path characteristics.

As we already know well the downswing path of the club must be as shallow as possible to ensure the longest possible flat spot (a wide letter U instead a narrow V) since the smaller the angle of the downswing path is the sooner the path touches the ground (and begins the flat spot, so to speak). Speaking theoretically, if the angle of the path was 0 degrees the flat spot would be as long as the route of the clubhead -- and, consequently, if the angle was 90 degrees the flat spot would be just a point on the ground). Take a look on the aerial view of Greg Norman here (notice also his slap-hinge release here) and imagine it is a 2-D action:

In reality, neither we can swing at 0 (because we would have to literally put our hands on the ground) nor at 90 degree angle (since the swing motion would be very limited as in case of short putts). We need to raise our arms and engage body pivot in order to make the swing strong enough and, thus, we usually make the path steeper than we wanted. Luckily, we can make the downswing path shallower what would help us with lengthening the flat spot without loss of power (the additional advantage is ensuring the inside approach to the ball). Let us list then possible biokinetical scenarios of shallowing the club (decreasing the angle) in the downswing phase below (not mentioning the pivot itself and pressures into the ground that are always present in all golf swings):
- enlarging the spine side tilt;
- thrusting hips forward (to the North);
- wrists action (rear wrist dorsal flexion and/or lead wrist palmar flexion);
- pushing arms or specific part of them forward (to the North);
- clockwise rotation of arms or specific parts of them,
and all possible random combinations of the above actions.

Enlarging the spine tilt (a.k.a. secondary spine tilt) is a natural phenomenon on the subconscious level and occurs in all correctly performed swing motions since we are bipeds and we transfer the dynamic weight in accordance with the orientation of the motion, i.e. to the West. When our head remains more or less stationary the amount of the spine side tilt must simply increase. Just to add, we recommended creating the tilt as large as possible at setup in our previous article so that the amount of its increasement (and, therefore, a timing-prone change in the swing) was reduced.

Thrusting hips forward (to the North) is just a phenomenon called early extension. This is something that we do not want in our swings since it brings lots of problems and should be eliminated, not promoted. We shall not deal with it any more then.

Wrists action (rear wrist dorsal flexion and/or lead wrist palmar flexion) as an unintentional move is rather rare and happens usually when the backswing ends very high independently on the backswing characteristics. It can be natural for Koepka's slight OTT-from-Inside pattern as well as for D.Johnson's slight reverse rerouting one.

Pushing arms or specific part of them forward (to the North) is just subconscious movement of the hands and/or rear elbow/forearm forward while letting the clubhead drop gravitationally down; the famous OTT-from-Inside procedure descripts this very well in detail. This is the most natural scenario for the vast majority of people because the orientation of the motion is in accordance with the orientation of the pivot. The motion of the hands forward shallows the shaft per se, however, additional shallowing moves (as e.g. humerus external rotation -- see: Hogan or wrist motion -- see: Koepka) can be of further assistance as well. This scenario is usually related to inside backswing paths and closed stances.

 

 

Clockwise rotation of arms or specific parts of them practically happens unintentionally to a bigger or lesser degree in all motions. However, a special place here is reserved for the so-called reverse rerouting procedure golfers. It is natural scenario only for a small percentage of golfers because the first move after transition is against the orientation of the entire motion. Additional shallowing moves (as e.g. wrist motion -- see: D.Johnson) can be of further assistance as well. This scenario is usually related to outside backswing paths and open stances.

After this introduction we can proceed to work on Part 4. of the series that will concentrate on presenting the most efficient shallowing procedure for our goals. Hopefully everything is clear now as the question of shallowing is often misunderstood in the macroscale and the errors in understanding can be easily transferred to the microscale.

Solutions to Lengthen the Flat Spot. Part 3. Controlling Up and Down Movements: the Spine.

Speaking about seniors, what bother them a lot are spinal problems. We need to help them to use the spine the way it is safe from injuries and "easy to use", so to speak. Not coincidentally, the dreaded up and down movements affect spine a lot, or better said, our spine takes huge part in performing these kind of movements during the swing motion (coupled with rotary motion of the spine which burdons the spine incredibly).

As mentioned in the Slap-Hinge Release articles, the key position for our spines to minimize any other movements is lateral side bend. That is why we recommended an exaggerated primary axis tilt so that the rotation of the spine (mainly thoracic, to a lesser degree lumbar and cervical parts) is not so violent. In fact, the best would be to set the spine in the secondary axis tilt position at setup; it is not quite possible because of the nature of the whole motion, but surely the amount of the secondary axis tilt amount will be diminished.

We have created recently very useful notions of WAB (well-anchored bow) and SWAB (stretched well-anchored bow) so that it is easy to have these ideas in mind. Please take a look above at this beautiful sequence of Sam Snead consisting of address position and transition. We would like to draw everyone's attention more to the process of "stretching the bow" than to creating the secondary axis tilt. We underline strongly also the word "well-anchored" as it has a vivid connotation to feet that have to be extremely quiet and stable as well as slightly closed feet line in relation to the target and flared out decently.

How to archor it well and stretch well ? We need to be firm on the ground with our feet first. Next we need to exaggerate the primary axis tilt in the pelvic area which is equal to move the lead hip laterally targetwise; if you remember the famous Hogan's bump at transition (above), it is easy to understand this move and perform it well at address. Please also refer to the two articles about the Firm Lead Side and the notion of fixed extension at address.
 

We simply need to sit onto the lead hip, so to speak which prepares the lead hip for retaining firm position before going to SWAB procedure. The best results were obtained when rotating both flexed hips medially (colloquially it refers to spreading buttocks away) which move is responsible for the stretching part. Important part is that this position helps to retain hips in flexion until they both start to extend and rotate laterally well before entering the impact zone unintentionally. Look how it looks in motion of a great ballstriker from the rear (Mac O'Grady):

Another important aspect in the Senior Swing is the so-called depressed rear shoulder backswing which is related very closely to the exaggerated primary axis tilt. We need to eliminate steepness of the shoulders (reducing up & down movements) from the entire motion as it makes finding long flat spot on a reliable basis very difficult. We always liked how the best ballstrikers were pivoting squarely to their spines but we never stressed that shoulder girdle can behave differently to the spine, e.g. flatter or steeper. We need definitely the first one, tending to be almost parallel to the ground and, to our grand pleasure, we can observe this phenomenon in many swings of past greatest champs and best ballstrikers. Presetting protraction and depression (mentioned earlier in our articles concerning The Arms Situation) surely helps a lot in achieving that. Lastly, having the flat rear shoulder backswing is entirely compatible to the preset rear elbow in flexion that we talked about in the last article.

It is unbelievable how many things still remain unseen and, thus, not used in the golf swing instruction industry. The next part no. 4. of the article series will be even more shocking for many, I believe.

Solutions to Lengthen the Flat Spot. Part 2. Controlling Up and Down Movements: Knees and Elbows.

There is no stabilization of the flat spot without neutralizing the impact of the changes in the body planes during the golf swing motion. These changes are inevitable taking into account the way humans are built. The most dreaded are the movements up and down of the body and arms. The flexion and extension movements in knees and elbows (up and down in golf so to speak) seem to be of critical importance, however, the spine side movements cannot be underestimated. Ideally, the setup position should match exactly the impact position but in theory only. Last but not least, the inventor of the flat spot concept, Mr. Phil Rodgers, wanted us to limit the up and down movements in the knee joints while not letting them to flex too much so that the spot was as long as possible in the impact zone.

Let us see what joints are the most vulnerable (red) for transverse plane movements from the ground up -- knee joints and elbow joints (for golfers practically only rear elbow joint as the lead one is not supposed to be in a flexion). Stabilizing their flexion/extension movements during the motion is of critical importance. As shown on this beautiful image of Ben Hogan from his 5L book, there are also joints of secondary importance in this matter (orange), such as ankle, hip and shoulder joints. What is great, it is easy to take control on these joints while we work on knee and elbow ones.

We have discovered, among others thanks to Abe Mitchell's wonderful work, albeit he did not say it so explicite, that one can easily control the flexion and extension via presetting torques in joints (external or internal rotation in both knee and rear elbow joints). As you might remember from our previous articles, we used to preset the rear knee joint in the process of taking the correct stance as well as rear elbow joint in the process of forming the Bio-K grip. We need now to neutralize the flexion/extension movements in both knees. Mitchell discovered that the most positive impact for him had been achieved via winding the muscles of thighs and and forearms forward (as shown on this picture taken from Abe's great book titled "Down To Scratch" below) which would make both knee and elbow joints immune to uncontrolled flexion or extension action there. 

Now a word on the stance -- since the winding is forward it is recommended to make a small but important adjustment in the diagonal stance. We recommend to close the torso and shoulder girdle in relation to the target line a bit which is very compatible to the process of creating some additional amount of axis tilt. By the way, we discovered a great method to do it (especially easy for RED golfers as they usually see their nose contour when looking at the target from an angle), namely, we use the contour of our nose to cover completely the pin (or the place we want our ball to land). Thus, a bit open shoulders after winding become a bit closed (less for short clubs, quite a lot with the driver) as we subconsciously move our shoulder girdle with the head while looking at the target. With the exaggerated axist tilt the rear elbow remains in flexion beautifully.

Finally, a word about the trigger compression method. Because of the winding the shift onto the rear side has to be exaggerated a little. The best results we obtained with mixing Mac O'Grady's one with linear shift back.Also pretty good method is what we can observe in Byron Nelson's swing, i.e. rear knee on its bouncing reverse way sort of pulling the rear hip back.

One might ask what is the difference between this setup and the setup we used to do aiming at maximizing sequentiality of the motion via the SPC concept. In fact, not huge at all. The only one serious difference is the opposite orientation of the rear knee joint preset due to winding the muscles forward. The rear elbow joint is exactly preset the way we recommend several years earlier. Take a look at this two photos:

Mind you, we are dealing with swing model for seniors, therefore, we would need to enhance the rotation forward of the whole body. Besides, winding rear thigh muscles forward also has an effect similar to presetting the rear knee joint (knee goes slightly inward with this manouver), albeit not so strong to be able to evoke a sort of self-induced countertorque as in case of the SPC oncept way of presetting it. Nevertheless, seniors must take into account ageing of their joints and bones and avoid hypertorques if they want to enjoy golf as long as possible. The most enjoyable info is that some automatism can be also introduced here despite lack of stretching human body's abilities to the limits.

Solutions to Lengthen the Flat Spot. Part 1. What can We Learn from Moe Norman ?

Let us start to propose some solutions that help to make the lengthening of the flat spot automatically using the properties of our human organism. Sadly, golf instruction do not deal with automatism -- perhaps theorists do not believe in that (as the action of human organism contains so many variables that it cannot be automated), perhaps they believe in muscle memory and repetitions, who knows. The truth is that although it is very difficult to find proper automating solutions -- they exist. Sometimes it is just a good brilliant idea that suddenly comes to mind, sometimes it is a hard work dedicated to observe the best ballstrikers that ever lived. This part one of the series is just a perfect example of the latter cases.

Moe Norman, a savage genius, whose legendary ballstriking is compared only to Ben Hogan. Tiger Woods said Moe and Hogan were the only one golfers who owned their swings. What does that mean ? To me it always sounded like a praise for automatism in their swings. Not coincidentally the key word of Hogan's best book "Five Lessons"is automatism (please revert for the details to the article named 'Mr.Hogan's Contribution to the Idea of Automating the Motion' here on our site). On the other hand, Moe Norman ironically said after nth ideally copied shots "Why is this game so easy ?"
We sincerely believe it is so easy because of serious automatism introduced into their swings, no doubt, supported with lots of training hours in both their cases.

We sacrificed lots of articles and vids to Ben Hogan in the past, time for the other genius ballstriker. What can we learn from Moe Norman then ? If you ask golf theorists why Moe was so great a ballstriker they would corcodantly say because of his single plane; of course, this is not true as Moe was not swinging at single plane (he was a double shifter who used to stay away from the ball with extended arms). Some others would say his wide stance contributed to this; we say not all people who perform wide stance at address are excellent balstrikers. Lastly, some says that "his feet remained planted, keeping the foundation and trajectory of the flight true" (both this quote as well as the above GIF taken from one of GolfDigest articles : https://www.golfdigest.com/story/what-you-can-learn-from-moe-no); this we find true, however, not as the cause, but the effect of what we are describing below.

Please look at his address with the driver...

...and the whole initial procedure with an iron...

What can we see there ? Placing the clubhead behind the ball -- an inch in case of irons, several inches in case of driver -- because of the fact that this is exactly where we want the flat spot to begin; in order to hit the teed ball on the upswing the flat spot must start earlier and end earlier. The whole procedure sort of presets the appearance of the flat spot in the impact zone as well as give signals to our subconscious mind to flatten the whole swing while approaching the impact zone. One can also subconsciously friendly hit at the ball (instead through it against ones subconscious mind) without losing swing speed prematurely. Last but not least, it gives more room for inevitable CoM shift to the lead leg without necessity of rapid increasement of the (secondary) axis tilt which can lead to inconsistencies. With all this it is very natural to swing with 'quiet feet' planted firmly on the ground even long after separation.

Also the distance between the clubface and the ball helps to set the correct path and clubhead angle for us. If the clubface is directly behind the ball our eyes cannot recognize ideal clubhead path and transfer it to out mind. We do not know that this was also Moe's intention (as he was incredibly straight hitter) but this seems so logical a consequence of Moe's set-up that it would be silly not to mention it. It is also worth noticing that for a neutral stock shot the clubhead (that lies behind the ball) should be placed according to the swing arc and not having its sweetspot in line with the ball -- slighty withdrawn with irons, much more with the driver (toe in line with the ball -- see the exaggerated image above).

The Senior Swing. Part 4. The Bow Tie Concept.

The flat spot must be as long as possible, therefore, the first contact with the soil must be done some time before the ball, not just before the ball so that erroring at hitting thin or fat can be eliminated. On the other hand, it cannot end just after the ball for the same reason . It cannot be V shaped since the timing of finding the low point would play too big a role. The sole of the clubhead should sweep through the ball. Moreover, the vertical swing must be wide, its radius must be as long as possible (remember the Jack Nicklaus's basketball image). The takeaway as well as the follow through must be wide and as long on the baseline as possible. A decent width of the swing arc is being achieved without its depth ! We are killing two birds with one stone here -- the arc is closer to our target line all the time during the swing motion and the pivot is not that critical which is very important for body-handicapped golfers. Also, the shoulder downswing plane is much less physically demanding than elbow downswing plane (especially the EEP).

First aid we can get is visual image of what we need to do. I am a bit familiar with the notion of the Bowtie method used to evaluate risks and consequencies. Our Bow Tie Concept is also based on the shape of popular men's decorative cloth but serves rather to minimize risks of playing bad shots. Let us juxtapose the image of the bow tie with the intercardinal directions symbolizing both backswing as well as downswing clubhead path (the flat spot in yellow covering the baseline close to the ball):

We see that recent golf swing instruction sometimes uses alignment sticks for training; they cannot be used in regular play though while the visualization of a bow tie on the ground in front of a golfer can be used everywhere and always. This image is very easy to absorb by the subconscious mind's eye (as on the bird's eye picture of Greg Norman), the more we are basically dealing with clubface perpendicular to the swing path in our work on the Senior Swing:

The two basic shot patterns, except of course the straight one, are the in-to-out SE/NW push pattern (where the flat spot is not short but is located long before the ball)  and the out-to-in NE/SW pull pattern (with almost no flat spot at all):

 Searching for both lengthening as well as correct placing of the flat spot close to the ball we need to chart all the possible scenarios for shoulder downswing plane (single shift from EP to TSP in TGM terms). It is worth mentioning here that e.g. reverse OTT loop (examples: Furyk or Trevino) are associated with elbow downswing plane only (double shift from EP to TSP and back to EP in TGM terms) hence this very reduced number of patterns mentioned. It is worth mentioning that a typical in-to-in SE/SW pattern (below) is not useful at all because it is impossible for our brain to associate the pivoting motion with creating the linear flat spot idea:

Let us start with a relatively common pattern for both ordinary golfers and great champions, a very subconscious-friendly in-to-neutral 'OTT from inside' pattern (SE/neutral) which is equally popular among elbow downswing plane golfers (e.g. Jones, Snead, Hogan, Boros) and shoulder downswing plane ones which we are interested in (e.g. Demaret, Mangrum, Irwin):

The problem with this pattern is that although the flat spot is close to the ball it is relatively shortish. To lengthen it without moving it back behind the ball we need to introduce an odd, at first look, the out-to-out NE/NW pattern:

It is impossible to swing like that in reality, however, it is possible to sort of bend the reality for our mind while trying to merge a slightly outside takeaway with a slightly outside follow through which results in approaching the ball from inside. This pattern is totally compatibile with less amount of body rotation (that anyhow exists and flatten both red arrows to baseline) and conversion of depth into width (what we discussed earlier). Not coincidentally, the only one golfer that can be close to this pattern is the late Jack Nicklaus who wanted to find a pattern close to swinging the clubhead along the baseline while literally sweeping the ball.
His pattern is not as sexy as Hogan's or Snead's -- perhaps this is why it is hard to find theorists that would try to understand it and promote it. This was true in my case before when I was not interested to analyze anything else from the EEP pattern, but finally it seems simple ageing with all its consequences made me start researching and finding the swing pattern of best golfer that ever lived...

 

The Senior Swing. Part 3. Mr.Rodgers's Argumentation about the Flat Spot.

Before we proceed to reveal our findings it would be unfair if we omit the original argumentation of the concept inventor, Phil Rodgers. Although the flat spot topic in fact does not take much space in the 'Play Lower Handicap Golf' book, there is another source. We have invested some time and money in finding and purchasing one for the old Golf Digest magazines with a detailed and heavily illustrated article about the flat spot idea (we use here scanned photos from this article) in which the author explains how to manufacture a long flat spot we all should desire to have. Let us present below the summary.

First of all, Rodgers recommends swinging level, not down. 'Think of hitting the ball in the back rather than striking down on it. The idea is to lengthen your flat spot, where the clubhead is moving parallel to the ground. You want to contact the ball at the start of the flat spot with your irons and the middle of the flat spot with your woods'.
We totally agree to the above knowing how disastrous hitting down on the ball can be when not being able to deliver the clubhead from the inside. Thinking about hitting in the back of the ball is great unless we learn how to avoid hitting the ground inches before the ball. Mind you, our subconscious mind learns on our bad and good experiences.

Next recommendation from the author is the idea of swinging underhanded up to the ball. Rodgers wants us to swing our arms down as low as possible while releasing lag angles as soon as possible. Obviously it should be a good receipt for lengthening the flat spot by starting it as early as possible before the ball. As our readers may remember from the 'Skipping Stones in Troy. OTT from Inside Revisited' article we argued that the majority of golfers need exactly the opposite idea to skipping stones move because it is not natural for them at all. Moreover, while recommending the slap-hinge release type with the in-to-in path we do not want at all the flat spot to start so early before the ball; neither we do want to base the downswing on a linear slide over the ball (it is worth mentioning here, however, that Rodgers is an advocate of the in-to-out swing path) -- hence we are not with the author here.

According to Rodgers we should keep the light end of the club (i.e. the grip) below the heavy end (i.e. the clubhead) in plane, '[...]which is another way of saying that you should swing the club on the same plane back and through. If your club is out of plane, either to the left or to the right, the clubhead will feel heavier'. And later he says: 'The clubface and shaft should always be in line with the straight arm in the swing. On the backswing and start of the downswing, the left is the straight arm. On the follow-through, it's the right'. Although we admit that this point can appear to be a little fancy, it is a valid one. We shall return to it in the part dedicated to the Bow Tie Concept.

This one is really important -- we argee fully with the author. One should stand tall, should maintain one's height with minimum of flex in the knees and centered head as well as one's lead side should feel long while the rear one (sagittal plane) should feel low (which corresponds well to the necessity of having a decent primary and secondary axis tilts that we mentioned in the 'Mastering Slap-Hinge Release' series of articles. There should be as minimal sitting down action during the downswing as possible. We will also revert to this section while discussing the head cradle motion in the context of relationship between the arc of motion of hands and the club in the downswing phase.

'Like a pendulum, not like a metronome' -- it is the motto of the last page of the Rodgers's article. He advocates more turning than sliding which we do agree to fully. We both seem to share the thought that centered pivot swings are more efficient.

This is the essence of the great concept that Phil Rodgers thought out. Our goal now is to find the best way to automate the process of obtaining the flat spot long enough for performing the slap-hinge release while swinging in-to-in. 

The Senior Swing. Part 2. A Short but Enlightening Story.

Imagine a new golfer's brain beginning his adventures with golf. The golfer of course tries to hit the ball straight, that's for sure. Next, he likes to hit the ball straight and get it airborne. His brain looks for solutions what to do with these funny sticks -- how to deliver them at the ball to fulfil these goals. And that is how the story begins...


The tabula rasa starts with steering the clubhead alongside the baseline (let us believe it is aimed flawlessly straight at the target) and, simultaneously, he/she wants to scoop the ball because it does not trust in clubs' lofts yet. The result is obvious -- he/she hits long before the ball. Phil Rodgers writes: "A slicer has little or no flat spot, and a hooker's flat spot is too far behid the ball". Thus, the brain thinks how to avoid it and concludes that hitting from the outside across the ball is a cure. The brain accepts this easily, it is easy to hit the ball this way because it lies on the ground. Moreover, everyone says that one should hit the small ball before the big one (our Earth). However, a new problem arises -- the ball does not want to go straight at the target, it goes well left of the target. Until now, the brain associated the direction of the ball with downswing path direction with the clubface square to the path (hence, by the way, the so-called old ball flight laws were so long en vogue and millions of golfers including the greats built the whole game around them). Now it becomes obvious that toying with the clubface angle and delivering an open clubface to the path results in making the ball start more to the right and it also seems to curve even more right to the target. The vicious circle running...

Let us begin the same story a bit differently. What would happen if this new golfer would not have hit the first balls fat ? Or better said, if this new golfer hits long before the ball but he does not hit it fat ? Or even better said, this new golfer is somehow able to create a long flat spot that starts long before the ball and then sweeps the clubhead evenly through the ball ? The answer is simple -- this new golfer starts to hit the ball relatively straight from the beginning (of course trust in loft must take some time but let's forget about it now).

The conclusion is -- the golf instruction for newbies should concentrate on automating the process of finding the best way to let new golfers hit it fat from inside without hitting it fat. IT MIGHT BE THE MOST IMPORTANT GOLF SWING TRUTH EVER WRITTEN FOR ALL GOLFERS. Both Rodgers and Nicklaus thought about the same idea as well but rather in the context of helping accomplished golfers to work out consistent swing without lots of timing issues and verbalized it not so explicite. Coincidentally or not, this is also our current universal goal with working on the Senior Swing principles, for both accomplished ones as well as weekend hackers. Stay tuned, we shall try to work out the method of automating the process of obtaining long flat spot.

P.S. More specific and  realistic graphics of the Flat Spot in our golf forum.

The Senior Swing. Part 1. The Introduction.

We have already decided that the senior swing (i.e. the motion for older and body-handicapped golfers) should be based on the slap-hinge release type for the reasons that has been already explained. It is also well known that this release type, although the most natural from all three, is also somehow timing-dependent in the sphere of a consistent and repeatable finding of the low point of the swing arc. There are two great concepts created by two great minds that will help us to search for the answers that are going to solve that problem.

The first one has been mentioned by arguably the best player of all times. The late Jack Nicklaus thought that the ideal swing plane is vertical (perpendicular to the ground) because clubhead is always on the baseline and, therefore, all shots would be perfectly straight. "The ideal way to play golf would be to swing the club in a vertical plane -- like a pendulum. That way your club would never deviate from your target line, and, assuming you could also devise a way the clubface square to the target, you'd be bound to hit every shot straight". Of course this is only half of the truth because: a. it is not physically possible to swing that way for a human and b. he was right only in one dimension (the ideal swing plane from the other dimension is horizontal (as in baseball swing) because clubhead is all the time on the ball level -- but it would merely touch the baseline for a very short one moment in time (not mentioning it is also not physically possible). In such situations usually the best equillibrium from the geometric point of reasoning is to have the swing path on a 45 degree angle.

 Moreover, it is also important to support the shaft with the rear forearm acting on the same plane as the shaft for as long as possible before and after the contact (hence the early elbow plane in a pivot-subdued swing motion). Not coincidentally, the EEP angle is also very close to 45 degree and perpendicular to the turning core:

Late Nicklaus's more vertical swing arc angle calls for something different though. As the vast majority of senior and body handicapped golfers cannot have a decent quality pivots (usually the biggest problems are associated with lack of depth in the body turn) it become obvious that the angle of the path must increase which calls urgently for some rescue adjustments in the swing. In TGM terms the elbow plane is being replaced by the turned shoulder plane and the rear forearm does not support the shaft being parallelly behind it approaching impact zone.

What is to be pointed out here the slap-hinge release also needs the same adjustments aimed at consistent and repeatable finding of the low point of the swing arc. Nicklaus claimed very wisely that the rescue is to wide the swing arc as long as possible in the sagittal plane. "An upright plane gives the golfer his best chance of swinging the club along the target line at impact. However, uprightness of plane must be accompanied by width of arc [...]."

It is perhaps enough to provide the motion with necessary clubhead speed, however, it is not enough to solve the problem of timing issues while finding low point. The correct answer is to make the bottom of the swing arc as flat as possible for as long as possible. We are now passing fluently to the second of the two great concepts -- this one was invented by famous player and theorist Phil Rodgers and called the flat spot. Let us quote the great man himself: "I want the club moving parallel, or level, with the ground when it strikes the ball, and continuing level for some five or six inches afterward. The parallel zone [...] is the flat spot". 

Rodgers argues wisely some advantages of the flat spot such as less resistance to the clubhead than in case of hitting down at the ball, clubhead moving more quickly in the impact zone, reducing shock to the hands or providing greater compression of the ball on the clubface. While he may be very right with all of them the biggest advantage of long flat spot is eliminating of timing issues that accompany the process of finding low point in the arc, which means the remedy we are looking for for the senior swing.