a helpful mental image...

Sluggo42 · December 10, 2020

watch this video to better understand lag and shaft position, not so much as how, but why. I think it will really help many players that are searching for answers

Vegan_Golfer_PNW · December 10, 2020

1 hour ago, Sluggo42 said:

watch this video to better understand lag and shaft position, not so much as how, but why. I think it will really help many players that are searching for answers

Thanks for sharing this. My pro that i go to for trackman helped me with this by telling me to have a wider stance to help my lower body stay ahead of my upper body (works for me, not necessarily everyone). As well, the first 3 or 4 protocols with the planemate also emphasize this point. It really makes me feel better seeing this video and that I don't need to make big swing changes, just get my impact position down.

cksurfdude · December 11, 2020

Good stuff, thx. In a happy coincidence, all the lessons I've been taking are essentially all geared towards initially getting me to move better so that I can start to learn to get into a better impact position.
(also happen to have a DST trainer .. although it has been sitting idle in the garage for a while...)

Kenny B · December 11, 2020

12 minutes ago, cksurfdude said:

Good stuff, thx. In a happy coincidence, all the lessons I've been taking are essentially all geared towards initially getting me to move better so that I can start to learn to get into a better impact position.
(also happen to have a DST trainer .. although it has been sitting idle in the garage for a while...)

So it's well-rested... ready for your winter boot camp training!

NC Golfer · December 24, 2020

Watched the vid: Basically, we are shifting (hip bump) in the downswing and rotating our torso in the downswing to create forward shaft lean? The flipping motion looks quite familar.

Wildthing · December 27, 2020

Seems like a the video is trying to explain that the golfer requires something called 'lag tension' to get to a good impact position with some forward shaft lean. I don't understand what 'lag tension' actually is apart from maybe the tension one feels in the lead arm when the dynamic weight of the club maxes out just after impact. But personally , I don't think I need a training aid with some visual etched line to provide me a guide on how to feel that position.

Actually ,there was quite a debate on another forum regarding lag tension where Bertie Cordle got personally involved to defend his position.

Questionable golf science! | Newton Golf Institute (proboards.com)

There is also a link to some research that Dr Sasho MacKenzie did relating to the above.

Assessment of DST Impact Line Technology Theory 20 sep 19 4 (dstgolf.com)

Note: After seeing the video again , I'm unsure whether Bertie's physics is correct about that 1st 'de-stablising torque' . He says "at full extension, when the clubhead is subjected to its maximal rotational torque, and because the clubhead is moving faster than the players hands, the clubface wants to flip over and rotate around the shaft and close very quickly". Then he goes on to say this explains why Dr Phil Cheetham's research found no difference in shot dispersion accuracy between high and low handle twist velocity (what does it explain? Makes little sense to me).

Also , where is his evidence regarding the 2nd destabilising torque where he infers that a flipping hand release action will increase the forward shaft bend of the shaft compared to a hand release action where there is forward shaft lean at impact? Why hasn't he mentioned clubhead droop ? Isn't that another golf club torque or it too small to be considered?

I'll need to check the above with Dave Tutelman but I suspect the degree of forward bend at impact could be dependent on several factors . The degree of hand couple/torque being applied by the hands on the grip , the timing of its application, clubshaft characteristics (ie. how quickly the shaft tries to restore its shape- its elasticity). I don't think a golfer has enough time to muscularly do things (ie. micro manage destabilising torques) at the grip end for it have much effect at the club end in the late downswing. The physics to close the clubface by impact would have had to be initiated a lot earlier in the downswing.

Also at 26:21 -26:46 he mentions 'Gear Effect ' with an image of an iron , but, unless I'm mistaken, there is no only some 'gear effect' with irons (check out link and extract below) but not as much as drivers.

Design Notes - Golf Physics p2 (tutelman.com)

Gear effect is sidespin which is the result of an off-center hit with a club whose center of gravity is well back from the clubface. Without both these conditions, gear effect does not happen. Here is a very short description of gear effect. If you are interested in more, I have written a very detailed article on it.

Let's see what causes gear effect. In the picture at the right, we have two off-center impacts, one on an iron and the other on a driver. Both are toe impacts, which means it is to the toe side of the center of gravity of the clubhead. (The CG is denoted by the four-quadrant black-and-white circle; it's a pretty common notation for CG.) What does Newton say about such an impact? The CG wants to continue moving forward in a straight line, but there is a force on the clubhead that is off that line. That creates a torque that wants to twist the club. The result is that the CG keeps moving forward, but the club rotates around the CG in a clockwise direction (red arrows).

The CG of the iron is close to the clubface. So, where the clubface and ball meet, this rotation (the red arrow) consists of the clubface "falling away" from the ball. This results in loss of distance (the momentum transfer is not as complete as it should have been), and perhaps the ball flying somwhat to the right as the face opens. But there isn't any special effect on spin.

The driver is a completely different story. Its CG is well behind the clubface. When the driver head rotates around its CG, the whole face of the club moves sideways. Look at the direction of the red arrow where the clubface and ball meet; it is mostly parallel to the clubface, with only a bit of "falling away".

So the club's face is moving to the right while the ball is compressed on it. The result is that the ball starts to rotate so its surface doesn't slide along the clubface; remember it's compressed so sliding is difficult. This rotation is the blue arrow in the picture. If the clubhead is rotating clockwise (as in the picture), then the ball rotates counter-clockwise. It's as if the clubhead and ball were a pair of gears, with their teeth meshing where they meet.

That's why a toe hit with a driver tends to hook. For all the same reasons, a heel hit with a driver tends to slice. You don't have this effect with an iron. Well, you do, but not nearly as much. The CG of an iron head isn't in the face; it is slightly behind the face. And since this was first written, iron heads are being designed with the CG further and further back, to make them more forgiving and higher launching. So today's irons have more gear effect than 20 years ago, but not nearly as much as drivers.

Edited December 28, 2020 by Wildthing

mclarencar · January 8, 2021

If your intent is to hit down your hands will automatically be ahead of the club head - I promise you because it it physically impossible to hit down any other way. Apparently you need to go here https://pro-essay-writer.com/ and read how to become a real writer.

Edited January 10, 2021 by mclarencar

tony@CIC · September 30, 2021

On 12/10/2020 at 11:03 AM, Sluggo42 said:

watch this video to better understand lag and shaft position, not so much as how, but why. I think it will really help many players that are searching for answers

A bit dry but great info. Now I understand why I'm better at fishing (aka casting) then golf.