A schematic diagram of the most important part of the golf swing (shift, turn, shift, turn)

[Chunkitgood]

To repay the kindness with which my prior posts have been received here, I have drawn up a schematic of the rotation of the body around the center of mass as the COM moves.

 

in the first image, the COM (x) is at the front edge of the pelvis, midway between the feet and even with the balls of the feet.  In the second, the COM has moved towards the right, but not much towards the golfer’s rear, in essentially a lateral move.  This is the first shift, in which there is also some tilt of the left shoulder down from its original position.  In the third image the golfer’s body has rotated around the center of mass located at the front of the pelvis in its new position, sending the sacrum towards the target.  (During this move the arms are moved more or less straight up in front of the body and the upper torso is extended…so the backswing may be described as “tilt, turn, extend.”). This is the first turn.  In the fourth image, their COM moves to the left of its original position, in another essentially lateral move.  This is the second shift.  In the fifth image, there is rotation around the COM in the position to which it moved in the prior move.  This is the second turn which takes us to impact.  The follow through is an extension of this turn which I leave to your imagination.

 

This is a corrective of the ideas, one of which appears to be harbored by most everybody, that the rotation is around the center of the pelvis, or around the tilted spine.  Instead it is around the COM which is somewhere in the neighborhood of the front edge of the pelvis, and moves first to the right and then to the left as described above.

 

This is a synthesis of the information in the following, none of which bear any responsibility for it.  Instead one might wonder at their failure to create such an explanatory synthesis themselves, so that I was an obliged to make for myself.  Since I am not a professional golf maven, it may contain errors.  Please feel free to correct them…if you can.
 

 

http://www.drkwongolf.info/biom/fgmom.html

 

https://www.youandyourgolfswing.com/tiger-woods-swing.html

 

https://www.golfdigest.com/story/swing-by-numbers-new-study-unlocks-6-swing-secrets

 

http://www.youtube.com/watch?v=66_yZ-tUoXA

 

 

 

 

[iacas]

Good golfers do not turn their pelvis around their COM. They more closely rotate it around the center of the pelvis. The bold, below, is far more accurate than the red.

 

7 minutes ago, Chunkitgood said:

This is a corrective of the ideas, one of which appears to be harbored by most everybody, that the rotation is around the center of the pelvis, or around the tilted spine.  Instead it is around the COM which is somewhere in the neighborhood of the front edge of the pelvis, and moves first to the right and then to the left as described above.

 

P.S. The Dr. Kwon link is not particularly relevant. It's talking mostly about GRF, the moment arm, and frontal plane torque. Even when he's talking about what you could call A-P force/torque… that's how we measure these things - around the COM. It doesn't mean every body part is rotating around that point.

 

Edited January 10 by iacas
Clarifying

[iacas]

To expand, and because it took only a few minutes of modifying an existing graphic, this is more representative of how the pelvis moves in a good golfer. The white dot is the origin so that we can "keep our place" as the pelvis translates laterally and rotates (black dot is the center of the pelvis).

 

P1 - Address

P2 - Pelvis shifts a little to the trail side

P3 - Pelvis begins turning around the center (otherwise you're seeing a lot of EE)

P4 - Pelvis begins moving forward (target) or "re-centers."

P5 - Pelvis continues to move forward as it rotates around its center

P6 - Pelvis mostly rotating, forward translation slows

P7 - Pelvis continues rotating, translation very slow.

 

We can, with 3D, measure these types of things. Good golfers do not rotate their pelvis around their COM.

 

Consider how silly DJ would look if he rotated around the orange circle:

 

 

[TheDeanAbides]

4 hours ago, iacas said:

To expand, and because it took only a few minutes of modifying an existing graphic, this is more representative of how the pelvis moves in a good golfer. The white dot is the origin so that we can "keep our place" as the pelvis translates laterally and rotates (black dot is the center of the pelvis).

 

P1 - Address

P2 - Pelvis shifts a little to the trail side

P3 - Pelvis begins turning around the center (otherwise you're seeing a lot of EE)

P4 - Pelvis begins moving forward (target) or "re-centers."

P5 - Pelvis continues to move forward as it rotates around its center

P6 - Pelvis mostly rotating, forward translation slows

P7 - Pelvis continues rotating, translation very slow.

 

We can, with 3D, measure these types of things. Good golfers do not rotate their pelvis around their COM.

 

Consider how silly DJ would look if he rotated around the orange circle:

 

 

That's the clearest visual I've ever seen of this motion. 

[Tanner25]

So, it's shift a little, turn AND shift more and turn?

[Scottbox]

13 hours ago, iacas said:

To expand, and because it took only a few minutes of modifying an existing graphic, this is more representative of how the pelvis moves in a good golfer. The white dot is the origin so that we can "keep our place" as the pelvis translates laterally and rotates (black dot is the center of the pelvis).

 

P1 - Address

P2 - Pelvis shifts a little to the trail side

P3 - Pelvis begins turning around the center (otherwise you're seeing a lot of EE)

P4 - Pelvis begins moving forward (target) or "re-centers."

P5 - Pelvis continues to move forward as it rotates around its center

P6 - Pelvis mostly rotating, forward translation slows

P7 - Pelvis continues rotating, translation very slow.

 

We can, with 3D, measure these types of things. Good golfers do not rotate their pelvis around their COM.

 

Consider how silly DJ would look if he rotated around the orange circle:

 

 

This is so great.

[joelotw]

Thank you Chunkitgood for bringing this topic up.

THANK YOU Iacas for a clear,concise scematic diagram and narrative on how the hips work in a

professional level golfer's swing!!

 

I can't wait for spring 

 

[dpc]

14 hours ago, TheDeanAbides said:

That's the clearest visual I've ever seen of this motion. 

This AMG vid covers this exact subject.  This was my head exploding moment: