The video has spurred debate amongst Miyahira and his followers along with Brian Manzella (www.brianmanzella.com) and his followers. For more information on the subject, I would recommend visiting the following sites:
www.jeffygolf.com (Miyahira centric site)
At Manzella’s last ‘Anti-Summit’, it was discussed that the initial direction of the ball’s flight was primarily where the clubface was pointing at ‘maximum deformation.’ Maximum deformation is another term for saying that it is when the ball compresses to its max.
One of Miyahira’s swing preferences is for the golfer to have a slow rate of closure. The rate of closure is the amount the clubface closes thru the ‘impact interval’ (initial impact-max compression-separation). Here’s a video showing an example of ‘slow rate of closure.’
Other golfers with a slow rate of closure are Jim Furyk and Dustin Johnson.
A higher rate of closure would look more like Luke Donald or Phil Mickelson:
The main point of the argument is whether or not the rate of closure from when the ball is initially contacted by the face will influence the ball flight when the ball reaches maximum compression.
Miyahira argues that it does, Manzella (and Trackman creator Fredrik Tuxen) claim that it does not.
The concept of rate of closure and ball flight still works in accordance with the D-Plane.
Initial D-Plane theory stated that the ball’s initial direction was about 85% due to where the face was pointing at impact.
The other 15% was due to the path. Then the curvature of the ball was due to the path’s relationship to the face angle at impact. One of the interesting findings brought forth by Trackman in the past two years was how the initial direction of the ball changed with the clubhead speed. As you will see below, only the fastest clubhead speeds had the face angle being close to 85% responsible for the initial direction of the ball flight.
With that, we also have to remember that face angle plays a big part in the actual curvature of the ball flight. Below is an example of the projected curve of the ball given 3 different impact conditions:
A) 0° face angle, 0° path = straight ball flight
B) +3° open face angle, 0° path = slice
C) -3° closed face angle, 0° path = hook
In each of the swings, the path was the same with relation to the target. But, the face angle changed and that subsequently changed the relation of the path to the face angle; which causes the change in curvature of the ball flight.
Where this relates to the arguments between Miyahira and Manzella is that if Miyahira is correct and the rate of closure can alter the clubface’s direction from ball contact to maximum compression, then the ball initial flight direction and curvature can change.
The main argument for the Manzella side is that the time from initial club-ball contact to maximum compression is roughly 0.0005 seconds. And that there is no way that the clubface can alter in that timeframe and therefore, rate of closure is not all that important.
They also argue that the Phantom Camera (which goes for $50,000 to $150,000 retail) cannot measure all of these factors. Furthermore, their claim is that it cannot accurately measure the Center of Gravity of the club and any change in face angle as the ball is being maximally compressed is due to the gear effect of the club; as missing the CoG of the club by 1 dimple causes the gear effect of the clubhead to come into play.
Miyahira argues that since Trackman does not actually measure the face angle at impact and that since nobody else has done concrete studies actually measuring all of the variables thru the impact interval, that Trackman and Manzella cannot dismiss his initial research.
The rub comes down that if Miyahira’s initial assertions are true, then it does provide some more interesting insight into ball flight. Hypothetically, if Miyahira ends up being correct Trackman could probably state that their face angle readings are a calculation based off of the point of the ball’s maximum compression rather than initial impact.
But, that would leave Trackman with a ‘hole’ in the system, not being able to measure the rate of the closure in the golf swing which would be important to the golfer’s capability of controlling the impact conditions. Let’s say we want to hit the ball straight and get the path and face angle at 0° square to the target. Now the golfer has to properly factor in rate of closure to more consistently achieve those numbers. For Manzella, this would be more devastating due to his recent studies labeled as ‘Project 1.68’ where he believes a low rate of closure in the swing is sub-optimum. That and he’s probably the biggest advocate for teaching with Trackman in the world. This would perhaps have to lead to utilizing a more expensive piece of equipment to figure out the rate of closure, like the ENSO machine which goes for around $200k and/or the Phantom Hi-Speed Camera.
If Miyahira were proven wrong, he would have to come up with a different reason why he thinks a slow rate of closure is more ideal in the golf swing. For most fans of slow rate of closure, like myself, they could justify in their minds that it is easier to time a slow rate of closure. But the actual scientific proof of that justification would still be lacking.