Analysing the opinions of Eric C

The video starts with his guest golf instructor (Kerrod Gray) demonstrating his table top drill that shows how the clubface opens during the backswing as the lead forearm pronates and then closes in the downswing as the lead forearm supinates.

A number of questions arise - i) when should the lead forearm supination phenomenon, which is causally responsible for the clubface closing, start in the downswing and ii) should the toe of the club bypass the heel of the club through impact.

Watch the video between the 5:10 - 5:59 minute time points. KG demonstrates his table top motion of the clubshaft showing how the clubface seems to progressively close during the simulated downswing action to become square at impact. EC then wrongheadedly states that the toe must pass the heel through the impact zone. KG not only agrees to that wrongheaded fact, but he offers an explanation between the 5:45 - 5:58 minute time point of the video when he states that the design of the club is such that it is not "equally weighted" if balanced on the finger and that it wants to roll either open-or-closed, and then KG wrongheadedly infers that it explains why the clubface cannot remain square to the clubhead path during the golf swing action.

I believe that there is nothing inherent in the design of a golf club - where the clubhead/clubface is angled at a ~90 degree angle at the hosel - that would automatically/inherently cause the clubface to roll during a golf swing action if the club is swung continuously on a single plane. It is simple to prove my assertion by watching a Golf Robot machine (Iron Byron machine) that is used to test golf clubs. There are two designs of a Golf Robot machine - in the one design there is a hinge mechanism at the hinge joint between the central arm and the clubshaft that has a rotary gear mechanism in situ that allows for a rolling motion of the club handle, but there is another much simpler design that only allows for a hinging action in one plane (the plane of the one plane swing) because there is no rotary gear mechanism at the hinge joint. In the latter design, they attach the club handle to the hinge joint in such a manner that the clubface is perpendicular to the single plane of the the hinge mechanism, and that will ensure that the clubface will remain square to the clubhead path throughout the backswing and downswing. So, it is physically possible to keep the clubface square to the clubhead path in that particular Golf Robot's entire downswing action - which proves that there is no physical law (no physical law inherent in the design of a golf club) that makes it impossible to avoid a clubface rolling phenomenon.

The major reason why the club handle rotates counterclockwise during the downswing of a human golfer is the fact that the lead forearm has to rotate counterclockwise in the downswing action (in inverse proportion to the strength of the lead hand grip); and the reason why the lead forearm has to rotate in a supinatory direction during the downswing is directly/causally related to the fact that the lead forearm pronated during the backswing.

So, consider these capture images of EC's table top drill demonstration using a neutral lead hand grip.

Image 1 is at simulated P4 position, image 2 is at simulated P5.5 position, image 3 is at a simulated P6.2 position and image 4 is at a simulated P6.5 position.

At address, EC stood with the back of his lead hand perpendicular to the ground and that means that his clubface must also be perpendicular to the ground (presuming a weak-to-neutral lead hand grip where the clubface will be straight-line-aligned with the lead lower radial bone and also the back of the lead hand - if the LFFW is intact and the lead wrist is not bent or bowed).

Note that the back of EC's lead hand, his lead forearm's lower radial bone and the clubface are horizontal relative to the ground at P4, which means that they all rotated 90 degrees clockwise during the backswing action. The primary casual factor for the 90 degree rotation of the back of EC's lead hand, and therefore the clubface, between P1 => P4 is a lead forearm pronatory motion of his lead forearm. So, to get a square clubface by impact EC must reverse the process by performing a lead forearm supinatory motion between P4 => P7, and you can visually see the back of EC's lead hand and clubface rolling counterclockwise in images 3 and 4, and the clubface must obviously roll 90 degrees between P4 => P7 in order for it to become square at impact.

In the video, EC states that the clubface should close steadily and progressively throughout the downswing (secondary to lead forearm supination) and that the counterclockwise rotation of the clubface should start happening immediately from the very start of the downswing.

Watch this other EC video on the same topic of "lead forearm supination" that EC performed with the renown golf instructor, John Dunnigan.

In particular, watch the video between the 10:30 - 11:30 minute time point of the video where EC and JD discuss when lead forearm supination must start in the downswing. EC suggests that it should start at P5, but JD interjects and asserts that it should actually start much sooner and that it should be initiated immediately after the start of the transition to the downswing.

That's impossible!!!

The "real life" reality is that most pro golfers only start to supinate their lead forearm at ~P5.5 and they do not supinate their lead forearm in the early downswing between P4 => P5.5. During the P4 => P5.5 time period, most pro golfers keep the back of their lead hand and their clubshaft parallel to their swingplane. The clubface will also be parallel to the swingplane - but only if they use a weak-or-neutral lead hand grip strength.

Consider these capture images featuring John Dunnigan, which I captured from the 11:03 - 11:15 minute time points of the EC video.

Image 1 is at P4, image 2 is at P5 and image 3 is at P5.5.

Note that JD has stuck a Chinese chopstick into the clasp of his lead hand's glove so that the chopstick is approximately straight-in-line with his lead forearm's lower radial bone and roughly parallel to the back of his lead hand. Note that his clubface is roughly parallel to that chopstick because he has adopted a neutral lead hand grip, and that at P4 where his clubshaft is lying on his swingplane, that his i) clubface, ii) clubshaft, iii) back of his lead hand, iv) lead lower forearm's lower radial bone and the v) chopstick are all roughly parallel to his swinplane. Between P4 => P5.5 he is presumably shallowing the clubshaft to a progressively shallower swingplane, but note that it never causes the chopstick to change its relationship to the swingplane and it remains roughly parallel to the instantaneous swingplane on which his clubshaft resides at every instaneous moment between P4 => P5.5. If he supinated his lead forearm between P4 => P5.5 it would cause the chopstick, and therefore the clubshaft, to rotate in a counterclockwise direction and that would steepen the clubshaft and throw it over-the-plane (an action which is often called a "tumble" action). That "tumble action" never happens in a pro quality golf swing action! In fact, if a pro golfer's clubshaft is shallowing between P4 => P5.5 so that it lies on a shallower plane at P5.5 (compared to P4), that usually means that his lead forearm must actually be more pronated at P5.5 (compared to P4).

Here is Jon Sinclair's graph showing the lead forearm pronation-supination phenomenon in >100 PGA tour pro golfers - based on his 3-D measurements using the TPI-3D-system.

Top = P4 position, AP = P5 position, Mid = P6 position and impact = P7 position.

The green lines represent one standard deviation, which means that ~68% of pro golfers fall within that range. Note that the green line range show that the "average" pro golfer's lead forearm is either neutral or slightly pronated at P4 and that there is no significant movement towards supination between P4 => P6 and note that the slope of the green graph only starts to move rapidly in the direction of supination after P6.

Note that there are three individual pro golfers presented in that image. Note that the red golfer does not change his degree of lead forearm pronation between P4 => ~P5.5 and he then starts his lead forearm supination phenomenon after P5.5. That type of pattern would naturally be expected in a golfer who does not shallow his clubshaft during the P4 => P5.5 time period. Note that the blue golfer increases his degree of lead forearm pronation to a small degree between P4 => ~P5.5 and he then starts his lead forearm supination phenomenon after ~P5.5 - and that type of pattern would naturally be expected in a golfer who significantly shallows his clubshaft during the P4 => P5.5 time period. Note that the yellow golfer starts his lead forearm supination phenomenon earlier - starting between P5 => P5.5. That early lead forearm supination pattern is usually combined with lead wrist flexion and it a rare pattern that is seen in only a few pro golfers (eg. Gary Woodland).

The "evidence" presented in Jon Sinclair's study is very convincing and it clearly demonstrates that the majority of pro golfers do not start their lead forearm supination phenomenon before P5.5 and that they only start to rapidly supinate their lead forearm between P6 => P7.

Two questions then arise - i) what is the primary factor that determines the magnitude of lead forearm supination happening between P6 => P7 and ii) does a large degree of pelvic/upper torso rotation between P6 => P7 mean that the golfer needs to perform less lead forearm supination in order to square his clubface relative to his clubhead path by impact?

Watch the first EC video between the 6:10 - 7:35 minute time points. Note that EC opines that if a golfer manifests a lot of body rotation in the later downswing (and he uses Viktor Hovland and Dustin Johnson as examples) that the golfer will then need to use less counterclockwise rotation of the lead forearm in the later downswing in order to square the clubface by impact. By contrast, EC opines that a greater amount of lead forearm supination will consequently be required if the golfer has a far more limited amount of body rotation happening in the later downswing.

EC is totally wrong!!! There is no negative/inverse correlation between the amount of body rotation happening between P6 => P7 and the amount of lead forearm supination required between P6 => P7. In fact, there is no causal correlation at all and the major factor that determines the amount of lead forearm supination required between P6 => P7 is the strength of the lead hand grip - pro golfers who use a weak-or-neutral lead hand grip will require a large amount of lead forearm supination between P6 => P7; pro golfers who use a moderately strong lead hand grip will require a moderate amount of lead forearm supination between P6 => P7; pro golfers who use a very strong lead hand grip will require a very small amount of lead forearm supination between P6 => P7 - irrespective of the amount of body rotation happening between P6 => P7.

I will now provide evidentiary proof in order to prove all of my claims made in the last paragraph.

Let's start with Justin Thomas' driver golf swing action - note that Justin Thomas uses a weak lead hand grip.

Image 1 is at P6, image 2 is at P6.5 and image 3 is at impact.

Note that the back of his lead hand and his lead lower forearm's lower radial bone are parallel to the ball-target line at P6. Note that there has been a small amount of counterclockwise rotation of the back of his lead hand and his lead forearm's lower radial bone happening between P6 => P6.5 due to lead forearm supination, and that much more is happening between P6.5 => P7. Note that his lead lower forearm's lower radial bone is angled about 20 degrees to the right at impact, which indicates that it rotated ~70 degrees between P6 => P7 (mainly due to lead forearm supination).

Note that JT has a very open pelvis/upper torso alignment at impact and that a large amount of body rotation happened between P6 => P7 - but it did not alter the fact that he needed to use a large amount of lead forearm supination (~70 degrees) during the P6 => P7 time period in order to get a square clubface by impact.

Let's now consider Collin Morikawa's driver golf swing action - note that he also uses a weak lead hand grip.

Image 1 is at P6.2, image 2 is at P6.5, image 3 is at P6.8 and image 4 is at impact.

I have drawn a green line over his lead lower forearm's lower radial bone, which is an useful marker to estimate how much he is supinating his lead forearm between P6.2 => P7.

Note that you cannot see a green line in image 1 because his lower lead forearm's lower radial bone is roughly parallel to the ball-target line at P6.2. Note that the green line is perpendicular to the ball-target line at P6.8, which means that his lead lower forearm's lower radial bone has already rotated ~90 degrees between P6.2 => P6.8. Note that there is another ~10-15 degrees of rotation of his lead lower forearm's lower radial bone happening between P6.8 => impact, so that he is rotating his lead lower forearm's lower radial bone ~100-105 degrees between P6.2 => P7 mainly due to lead forearm supination - despite the fact that he is rotating his body by a very large amount in his later downswing so that he ends up with a very open pelvis alignment at impact. That fact shows that having a very active body rotation in the later downswing does not diminish the amount of lead forearm supination required during that same time period if one adopts a weak lead hand grip strength.

Why does Collin Morikawa need an additional ~25-30 degrees of lead forearm supination in his later downswing to get a square clubface by impact - compared to Justin Thomas who also uses a weak lead hand grip? The answer is related to the fact that CM has a very bowed lead wrist at impact, which angles his clubshaft backwards away from the target creating a large amount of forward shaft lean. By supinating his lead forearm more than usual (for a golfer who adopts weak lead hand grip) he can decrease the amount of forward shaft lean to get his desired amount of forward shaft lean at impact (see image 4).

Let's now now consider Viktor Hovland's driver golf swing action - note that he uses a moderately strong lead hand grip.

Image 1 shows VH at address - note that his lead forearm's lower radial bone is angled ~45 degrees to the right secondary to the fact that he adopts a moderately strong (3+ knuckle) lead hand grip at address.

Image 2 shows VH at impact - note that his lead lower forearm's lower radial bone is angled ~45 degrees to the right (and it is no different in degree relative to address).

Consider the amount of counterclockwise rotation of his lead forearm's lower radial bone that happens between P6 => P7.

Image 1 is at P1.5 (because this swing video did not start at his P1 position), image 2 is at his P6 position, image 3 is at his P6.5 position and image 4 is at impact.

Note that VH has adopted a moderately strong lead hand grip strength at address so that his lead lower forearm's lower radial bone is angled about 45 degrees to the right. Note that his clubface is presumably facing the target at address (P1) and that it is ~45 degrees closed relative to the back of his lead wrist.

Note that VH's lead lower forearm's lower radial bone is ~90 degrees open relative to the ball-target line at P6, ~60 degrees open relative to the ball-target line at P6.5 and ~45 degrees open relative to the ball-target line at impact. Note that his 45 degrees open alignment of his lead lower forearm's lower radial bone at impact allows him to automatically/naturally get his desired amount of forward shaft lean at impact and it also allows him to get his clubface square at impact. VH is using very little lead forearm supination (~45 degrees) during his PA#3 release action that is happening between P6 => P7 in order to get his clubface square relative to his clubhead path at impact because he uses a moderately strong lead hand grip. It is not due to the fact that he is rotating his body a lot in his later downswing between P6 => P7 so that he ends up with an open pelvis alignment at impact - in fact, from a comparison perspective, note that he is rotating his body even less counterclockwise in his later downswing than Justin Thomas and Collin Morikawa and his pelvis is less open at impact.

It is a myth to believe that rotating the body (pelvis/upper torso) a lot in the later downswing between P6 => P7 decreases the amount of counterclockwise lead forearm rotation required between P6 => P7 in order to square the clubface by impact - as EC wrongheadedly suggested in his video.

I criticised Eric Cogorno (EC) in my initial post for claiming that a golfer should start the lead forearm supination phenomenon as early as possible in the downswing, and I demonstrated that it never happens in any pro golfer.

I sent a link to this thread to EC, and I noted that he has now produced a new golf instructional video on the topic of clubface closing where he no longer states that counterclockwise of the lead forearm should occur during the P4 => P5.5 time period.

Here are some of the pro golfers that he features in his video.

Image 1 = Justin Thomas; image 2 = Tommy Fleetwood; image 3 = Adam Scott; image 4 = Rory McIlroy; image 5 = Brooks Koepka, image 6 = Dustin Johnson.

EC states that at P6, the toe must be rotated more clockwise than the heel of the club, and he calls this phenomenon "closing the clubface relative to the shaft". He incorrectly claims that this visual phenomenon, where the toe of the club is tilted more groundwards relative to the heel, is due to an active biomechanical maneuver involving the lead wrist angle (in the plane of lead wrist extension => flexion). However, the true reality is the fact that the most common reason why the toe of the club may be tilted more groundwards at P6 is due to the fact that the golfer is using a stronger lead grip strength, where the clubface will be more closed relative to the back of the lead hand at address if a golfer adopts a stronger lead hand grip - and that visual phenomenon at P6 does not imply that the golfer is actively bowing his lead wrist between P4 => P6.

So, let's thoroughly examine those 6 images of pro golfers at their P6 position.

Starting with Justin Thomas (image 1). I have drawn a blue line parallel to his clubface and a red line parallel to the watchface area on the back of his lead lower forearm. JT uses a weak lead hand grip, so the back of his lead hand should be straight-line-aligned relative to the watchface area of his lead lower forearm if he has an intact LFFW alignment. However, note that the back of his lead hand is actually angled back slightly (relative to the back of his lead lower forearm) due to the fact that he is actively bowing his lead wrist to a small degree, and that causes the blue line to be slightly closed relative to the red line. JT does not use the twistaway maneuver during his lead wrist palmar flexion phenoemnon, so the degree of clubface closing is very small.

Image 2 shows Tommy Fleetwood at P6. Note that his clubface (blue line) is closed relative to the watchface area of his lower lead forearm (red line), but it is solely due to the fact that he adopts a moderately strong lead hand grip strength at address. Note that the back of his lead hand is not closed relative to the watchface area of his lead lower forearm, and he is not actively bowing his lead wrist between P4 => P6. It is totally incorrect to claim that TF is using an active lead wrist bowing action between P4 => P6 - as Rob Cheney wrongly infers in this post at newtongolfinstitute.proboards.com/thread/999/scott-cowx-motions-support-wrist?page=1&scrollTo=12953

Image 3 shows Adam Scott. Note that the blue line is closed relative to the red line, but that is solely due to the fact that AS adopts a moderately strong lead grip at address. Note that AS is not actively bowing his lead wrist - note that the back of his lead hand is not closed relative to the watchface area of his lead lower forearm.

Image 4 shows Rory McIlroy. Note that the blue line is slightly closed relative to the red line, but that is solely due to the fact that RM adopts a moderately strong lead grip at address. Note that RM is not actively bowing his lead wrist - note that the back of his lead hand is not closed relative to the watchface area of his lead lower forearm.

Image 5 shows that Brooks Koepka's blue line is more closed relative to the red line - compared to the degree seen in the Tommy Fleetwood, Adam Scott and Rory Mcilroy images - even though he also uses a moderately strong lead hand grip (to an equal degree) compared to those 3 other pro golfers. The reason for a slightly greater amount of clubface closing at P6 is due to the fact that BK is actively palmar flexing his lead wrist between P4 => P6 and that adds an additional amount of clubface closing.

Image 6 shows that Dustin Johnson's blue line is more closed relative to his red line at P6 - compared to BK (even though he adopts an equally strong lead hand grip strength that is moderate in degree) - and that is due to the fact that DJ has an exaggerated amount of lead wrist bowing at P6.

EC has also inferred that if a golfer closes the clubface more during the earlier downswing between P4 => P6 by using an active lead wrist bowing maneuver (as seen in DJ's P6 image), that he will need to use less counterclockwise rotation of the lead forearm between P6 => P7 in order to get a square clubface by impact. He is totally wrong - because the opposite fact is true. If a golfer uses the bowed lead wrist technique to close the clubface between P4 => P6, then he will have to use more lead forearm supination between P6 => P7 in order to get a square clubface by impact - and that is because lead wrist bowing causes a greater degree of backward angulation of the clubshaft relative to the lead forearm during the later downswing as the lead wrist becomes more ulnar-deviated.

I have demonstrated that "fact" in great detail in topic number 4 of my downswing chapter at perfectgolfswingreview.net/downswing.htm#topic4

I have also discussed this issue on multiple occasions in this NGI golf forum.

Here is just one example that demonstrates this "fact".

Justin Thomas and Collin Morikawa both use a weak lead hand grip, but CM uses the bowed lead wrist technique while JT uses the intact LFFW swing technique. According to EC, it would mean that CM (who uses an exaggerated lead wrist bowing maneuver between P4 => P6) should have to use less lead forearm supination between P6 => P7 in order to get a square clubface by impact. However, the "real life" reality is the opposite because CM has to use ~30 degrees more lead forearm supination between P6 => P7 than JS (100 degrees versus 70 degrees).

Here is the proof.

Justin Thomas' late downswing action.

Image 1 is at P6 and image 3 is at impact.

Note that the back of JT's lead hand is facing the ball-target line at P6 and that his lead forearm's lower radial bone is parallel to the ball-target line at P6.

Note that JT's lead lower forearm's lower radial bone, and the back of his lead hand, have rotated ~70 degrees between P6 => P7.

Collin Morikawa's late downswing action.

Image 1 is at his P6.2 position. Note that his clubface is slightly closed (relative to his clubhead path) because he used the bowed lead wrist technique between P4 => P6.2. Note that the back of his lead hand is facing the ball-target line at P6. Note that his lead forearm's lower radial bone is parallel to the ball-target line at P6.

Note how his lead lower forearm's lower radial bone (green line) rotates ~100 degrees counterclockwise (mainly due to a lead forearm supinatory motion) between P6.2 (image 1) and P7 (image 4) - even though his clubface was already closed to a small degree at P6.2. The reason why he needs ~30 degrees more counterclockwise of his lead forearm's lower radial bone (compared to Justin Thomas) is due to the fact that his lead wrist bowing technique is angling the clubshaft more back (away from the target) relative to his lead forearm and he therefore needs to use more lead forearm supination to get his i) desired amount of forward shaft lean + ii) a square clubface at impact.