Dr Mann
There is a thread already on Golfwrx already discussing this book .
www.golfwrx.com/forums/topic/1387984-jim-hardy-the-release-golfs-moment-of-truth/page__hl__%20jim%20%20hardy%20%20releaseFWP (who is Michael Martin I think) has been consistent with his views, bhp doubtful of Hardy's opinions but there are no comments from Iteach.
Example comments from FWP :
No offense, and this isn't an ego thing, it's not that I COULD be right, I am right. I have access to the largest 3D database in the world at work and the best players in the world do not move like Hardy says they move. He doesn't say they are feels. He says it is occurring. I am glad he has helped you and I couldn't care less what anyone feels in their swing but I do care when instructors publish measurably false information as fact/truth
I can tell you. The database I have access to is one of, if not the largest database of tour players in the world. It is not my info to publish as it "belongs" to the teacher who owns the facility I work at. The lead wrist is flexing almost right up to impact. The right hand is not thrown under and is massively extended at impact. The forearms absolutely rotate in all golf swings through impact and they rotate hard. The left wrist is more ulnar deviated at impact than address. It does not "return" to its setup position.
Define good swing? I would say the swing of anyone who is better than a plus 2. Can define it much narrower though and narrow it down to tour winners if you want.
Where do you look? If you drove a stake through the snuff box on the top of the right wrist straight through the bottom and look there it is clearly rotating. It is also rotating faster than the arm is at the elbow. The ulna and the radius are rotating. If you "can't see" that it's just willful ignorance. I didn't say anything about the arms rolling over. I didn't say they did or that they do. I said they rotate. Don't build a straw man around something I did not say.
Assuming there is forearm rotation"? No assumptions being made I assure you. As for the rest of your comment. I think there can be merit to ANY feel if it achieves the proper mechanic. I do think some feels are better than others and the hardy stuff strikes me as less than ideal because it is so far removed from what is actually happening. I have seen numerous golfers get so far down the rabbit hole with this stuff and just go backwards and backwards. I am sure some of the opposite story but I have seen enough to know there is extreme danger with some of these ideas.
Nowhere have I found fault with mr. Hardy's achievements or hard work. In fact, I rather admire them. It is his information I find fault with. Nothing I have said is personal. By all accounts mr. Hardy is awesome. The one time I met him he was great and we discussed our mutual passion for fly fishing. This is purely about golf swing and I have left it there. Thanks for attacking me though. That's great.
Nobody is hating. I liked mr. Hardy when I met him. I just know he isn't technically correct in what he says. Any feel can be valid as long as it gets somebody to make the proper mechanic. The problem you will run into is if you actually start doing what he says happens you are toast.
Grip strength plays little as to how the forearms rotate. The pivot has little to do with it. The club face has the most to do with it. One of the biggest differences in + handicaps and even single digit handicaps is how soon +handicaps/tour players begin closing the club face. It happens much sooner than you would think.
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PS
I also received this reply from Dave Tutelman when I gave him the example of the 3D AMM stats for Iteach's student asking why there should be flexion in the downswing, why such a small degree of extension through impact for at least 15 inches (if rapidly extending ) and what affect (if any) the collision with golf ball would have on the wrists extension.
When I first looked at his explanation it seemed quite logical .His real life exercise is advocating an earlier gradual release of PA3 (between P5-P6) by using flexion to 'stay on plane' (via inertial forces that ensures 'on-plane stability') while only undergoing a partial release of PA2. But do virtually all pros do this to some extent ? The 2D Phantom Camera image frames still do not reflect this and I still don't understand how
ulnar deviation could be diluting the extension.
Further , with regard the 15 inches where the clubshaft is not bypassing the left arm , if we used the example below , that would equate to clubhead movement of 0.7 inches per millisecond (after impact) due to angular velocity. So for 15 inches , that would work out as follows:
0.7 inches equiv to 0.001 secs
1 inch equiv to 0.001/0.7 = 0.0014 secs
15 inches equiv 0.0014 x 15 = 0.02 secs
If the angular velocity is halved , then we have 1783/2 = 892 deg / sec
Therefore for 0.02 secs (for those 15 inches post impact) = 892 x 0.02 = 17.8 degrees.
That's still too much and should show the clubshaft passing the left arm very early post impact? So Tutelman is describing one type of action that he says secures 'On Plane Stability' without any conscious manipulation and letting inertial forces do the flexion/extension. But he still can't say for certain what is actually happening through impact although inferring that ulnar deviation could dilute the effect of extension (but I don't think he can back up that claim 100%).
We really do need a much greater high speed data gathering 3D system to confirm what's really happening through impact.
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Tuteleman's respone to my email:
Let's look at P6 (actually a little earlier), just before impact,
and just after impact.
Here's something important: let's bear in mind where the clubface is
before P6 and at impact. I'm going to assume a release between the
slow rate-of-closure and fast rate-of-closure. (You mentioned Phil
Cheetham; he did some very good work on that question as his thesis
topic.) So my model is that the clubface closes just about in sync
with the loss of lag. At a 90° lag the clubface is in the swing
plane, and at impact the clubface is perpendicular to the swing
plane. We KNOW the latter is true within a few degrees for ANY
successful golf swing, or the ball would not go anywhere near the
target.
Let's look at how we get from 90° lag (actually a bit before P6, but
not all that much before for a good golfer) to impact.
(1) At 90° lag, any in-plane angular motion of the club is
going to be between radial and ulnar deviation, not between flexion
and extension. You correctly identified that.
(2) Coming into impact, the clubface is square or almost
square. So any in-plane angular motion of the club is going to cause
flexion to extension motion, not radial to ulnar motion. I'm sure
you'll agree with that as well.
Let's look at the consequences of that. At impact (I'll say "at"
when I mean an infinitesimal time before impact), the clubhead is
moving at, say, 100mph. (Could be less or more; let's pick a number.
100mph will be different in degree from, say 120mph or 70mph, but it
won't differ in kind. We will get an answer in the right ballpark.)
* 100mph is 1760ips, which is 1.76 inches per millisec.
* Clubhead speed for a decent swing is going to be 80%+ due
to angular motion and no more than 20% due to hand speed. So we've
got 0.8*1760=1400ips (approx) due to angular velocity.
* 100mph is a driver speed, so let's use a club length of
45". If the clubhead moves 1.4 inches in a millisecond this will equate to 1783 deg/sec.
Thus at impact we've got a flexion-to-extension rate of 1783
deg/sec. It's all flexion-extension because the face is square at
impact. This is not an average over the entire downswing nor even
most of the downswing. It is the instantaneous angular velocity at
impact, and is much higher than that at P6 or earlier.
(3) But how did we get all that flexion during the
downswing? For most golfers (not Dustin Johnson maybe, but most
golfers), the left wrist is more or less flat at transition. OK,
we're going to assume a light grip allowing the club to "freewheel"
(Alistair Cochran's choice of words, and I think it is very
appropriate). The inertial forces on the club are going to keep it
more or less in-plane from 90° lag (somewhere before P6) to impact.
(If this is a mystery to you, look at my article on the stability of
the swing plane:
tutelman.com/golf/swing/stability.php<http://tutelman.com/golf/swing/stability.php>)
Time for a real-life exercise. Grab a club and assume the 90° lag
position. The clubface is in the swing plane. It has to square up --
rotate 90° around the shaft -- by the time it gets to impact.
Now move to P6 or a little beyond it -- say 45° of lag still there.
With a flat wrist and all the release in radial-to-ulnar motion, the
face is still in-plane. BUT IT SHOULD NOT BE! It should be squaring
up. If we assume it squares up about the same rate as lag is lost (a
reasonable assumption), the face should be 45° to the swing plane.
Try making that happen, but ONLY WITH SUPINATION. Notice how the
club rotates out of plane. Way above the plane. The only way to get
the club back in plane and still satisfy 45° lag and 45° face
closure is to add wrist flexion. Go ahead. Do it. Try it. (I may
make a video of this some day, but not in time for our discussion.)
Is that a complicated movement for a golfer to make? Well it would
be if the golfer were making it consciously and/or making it with
wrist torque. But the inertial forces that make the swing plane
stable just create that flexion. Why? Because there is nowhere else
for the wrist to go if inertial forces are both releasing the lag
and keeping the club in-plane -- and they are.
This is something that too many mathematical models of the swing
ignore. I suspect they've gotten a lot better by now.
But early
models had the
problem of not recognizing the need for this degree of freedom. And
it is why the measurements show that substantial wrist flexion
occurs before it begins to turn to extension. It must happen to
allow the club to stay in-plane while lag releases and the clubface
squares up.
(4) If you're still with me... What about very little
further extension after impact? OK, we're banging the clubhead into
the ball at 100mph. 80mph of that is due to the club's angular
velocity, and 20mph due to linear hand motion. The mechanism that
causes the ball to launch is momentum transfer. That momentum comes
from the clubhead. During impact, the clubhead loses about third of
its speed, down to maybe 65mph. The shaft is very light and the CG
of the club is way toward the head, so the hands are not going to be
slowed much if any. Let's say hands keep going, and the 35mph loss
of clubhead speed all comes from loss of angular velocity. (That is
pretty much true.)
So, the speed due to angular velocity goes from 80mph to 45mph, a
loss of almost a half. Therefore, the loss of angular velocity is
close to a half. And remember, in the vicinity of impact the square
clubface means that all in-plane angular velocity of the club is
flexion-to-extension.
That doesn't explain the detailed numbers you
cited, but it certainly trends in that direction.
And in 15 inches,
we might have ulnar deviation diluting the extension effects, since
the clubface keeps turning.