Synthesis of Transition Ground Reaction Forces

[Michael Jacobs]

The synthesis of High End Ground Force Transition Phase of Swing a new quote for the history books from just a pro:

"The initial front back shearing force of the take away is counter clockwise to the golfer - Left foot back - right foot forward.We know that this then shifts to clock wise {left foot forward - right foot back} during a so called 'transition'
Here is the key:
The shift to Clock wise for pelvis transition happens before the Pelvis actually is seen commencing its downswing. The golfer's torques show in late backswing {prior to pelvis transition} that the troques at the ground already have reversed to clockwise even though the pelvis is in its final moments of still rotating back from the inertia of the rotation.
So the initial Clock Wise Anterior Posterior Shear should take place while pelvis is still finishing its backswing rotation. So TRUE TRANSITION is even Earlier than thought" Michael Jacobs

 

[mgranato]

The ground force torques (should) happen in advance of the pelvis changing directions, and the pelvis changing directions (should) happen in advance of the transition (club changing direction)? So the transition actually begins 2 "steps" ahead of the club changing directions if we're to use the ground to our advantage?

What is the best camera angle to see these shear forces?

 

[wulsy]

What is the best camera angle to see these shear forces?

The mole angle.

 

[WoodbridgeGolf37]

Any Snowboarders Out There?

I'm hardly an expert on the gnar-gnar but the feeling I got when correctly applying the shearing forces during the takeaway that Michael describes in his video is similar to that of a heelside turn on a snowboard.

I still haven't gotten the frontside turn/transition aspect down yet, but the swing already feels much more automated.

Thanks Again Michael!

 

[ZAP]

I just got finished watching the GRF video for the first time. I am going to need to watch it again. Being left handed and trying to interpret that stuff backwards sometimes makes me know what students with dyslexia feel like. Left is right and forwards is backwards....sometimes. The alignments stuff is something I knew from my days studying biomechanics in college in terms of other athletic movements. Finding time the rest of this week to watch again is going to be interesting. Guess there is always the weekend.

 

[Matt Bryda]

Any Snowboarders Out There?

I'm hardly an expert on the gnar-gnar but the feeling I got when correctly applying the shearing forces during the takeaway that Michael describes in his video is similar to that of a heelside turn on a snowboard.

I still haven't gotten the frontside turn/transition aspect down yet, but the swing already feels much more automated.

Thanks Again Michael!

For a left foot forward stance "regular foot"
and a very flexible board.

 

[birly-shirly]

I'm not sure I follow. Is this any different from saying that the force that rotates the body in one direction has an equal and opposite force where the feet meet the ground?

 

[btp]

Seems like the video had similar findings to the sports medicine study? http://www.jssm.org/vol9/n1/18/v9n1-18pdf.pdf

Conclusion
Specific characteristics of trunk rotation and weight transfer
patterns during the golf swing were found between
two different skill levels of golfers. The significant difference
in the kinematic and kinetic variables existed mostly
in the transition phase of the swing, such as in middle of
back swing, in the middle of down swing, and in the middle
of follow through. Earlier horizontal rotation of the
trunk accompanied with earlier weight transfer to the trail
foot in the middle of the backswing was evident in the
skilled golfers when compared to the low skilled golfers.
Similarly, the pelvic horizontal rotation in the downswing
motion occurred significantly earlier with a rapid weight
transfer to the lead foot in the skilled golfers while the
low skilled golfers showed a delay in these motions. As a
consequence of the motion pattern leading up to the ball
impact, less horizontal rotation of the upper trunk and
more posterior pelvic tilt were evident in the middle of
follow through motion for the skilled golfers. Collectively,
the results of this study may be beneficial for the
golf swing instruction for low skilled golfers to improve
their skill in a full shot golf swing.

Key points
• Different trunk rotation and weight transfer patterns
were found between skilled and low skilled golfers.
• Earlier trunk rotation accompanied with earlier
weight transfer to the trail foot during the back
swing was evident in the skilled golfers.
• Earlier pelvic horizontal rotation with a rapid weight
transfer to the lead foot during the downswing was
evident in the skilled golfers.

 

[Tony D'Antonio]

It's not scientific and it is probably a competitor so I won't post the link but there is a guy who has videos on the internet that talks about these forces and how he sets these forces clockwise up through his feet while he swings. I've always felt my swing get tighter (in a good way) and more consistent when I concentrate on making sure my footwork is solid. In one of this guy's videos he is with Elkington who mentions being able to wear long, metal spikes at his home club, Champions in Texas. He makes a valid point when he relays a story about Jackie Burke (a fellow Champions member). Burke said that when Usain Bolt wins the 100 meters wearing soft spikes they'll switch their policy at Champions to ban metal spikes. I think there is something to this for the golfer looking to build a swing based on this ground force torque data.

 

[Frans@France]

... Burke said that when Usain Bolt wins the 100 meters wearing soft spikes they'll switch their policy at Champions to ban metal spikes....

+!

 

[spktho]

It's not scientific and it is probably a competitor so I won't post the link but there is a guy who has videos on the internet that talks about these forces and how he sets these forces clockwise up through his feet while he swings. I've always felt my swing get tighter (in a good way) and more consistent when I concentrate on making sure my footwork is solid. In one of this guy's videos he is with Elkington who mentions being able to wear long, metal spikes at his home club, Champions in Texas. He makes a valid point when he relays a story about Jackie Burke (a fellow Champions member). Burke said that when Usain Bolt wins the 100 meters wearing soft spikes they'll switch their policy at Champions to ban metal spikes. I think there is something to this for the golfer looking to build a swing based on this ground force torque data.

I know who/what you are referencing and the forces Michael suggests are applied differently.

 

[Tony D'Antonio]

It would be interesting to actually measure the ground forces 'my guy' applies versus what he thinks he's applying. Maybe the bottomline is that 'my guy' stabilizes his lower body by applying ground forces the way he does and that the stabilizing is the important component and not the direction in which the forces are applied?

I know who/what you are referencing and the forces Michael suggests are applied differently.

 

[btp]

FedExCup Ad: Arnold Palmer Tea - YouTube Some would call it an Arnold Palmer, others might call it a Mark Steffenhagen.

 

[ZAP]

My ten year old son was having trouble almost falling down when he swung. Had him think about starting the backswing with the forces on the ground like the video. Instant improvement. Now he can explain it to me.

 

[Bonesy]

Can one pre-set the counter clockwise shearing force against the ground? I don't think I'm coordinated enough to take the club away and "shear" at the same time.

 

[mgranato]

Can one pre-set the counter clockwise shearing force against the ground? I don't think I'm coordinated enough to take the club away and "shear" at the same time.

That's kinda how I do it, Bonesy. I don't go full on, but I give it a little gas before the backswing gets going. I find it's easier to start one thing at a time (even if it's just a tiny head start) rather than two at the same time.

Something that I'm also finding is that trying to sustain those shear forces at all puts too much restriction in the pelvic turn going back. The feeling is more of getting the shear forces ramped up, then bring 'em back down without any effort to sustain them. This "backing off" is meshing very nicely with the timing for the reversal to the clockwise shearing in the pelvis transition from back to forward.

 

[ryant91]

You all should try to learn this one step at a time. Like without your club. This is a natural occuring motion in extreamly good moves. it occurs so quickly you really wont feel like you have time to increase or decrease the shear.

 

[mgranato]

You all should try to learn this one step at a time. Like without your club. This is a natural occuring motion in extreamly good moves. it occurs so quickly you really wont feel like you have time to increase or decrease the shear.

Good point, Ryan. What I was referring to above was in the rehearsal of the initial takeaway to when club reaches parallel. A very small distance and time frame, and as you said, easier to digest in small bites.

 

[Dariusz J.]

Can one pre-set the counter clockwise shearing force against the ground? I don't think I'm coordinated enough to take the club away and "shear" at the same time.

Hogan in his post-secret times did it very visibly if you know where to look.

Cheers

 

[magicmarker]

Looking for the force plates, looking, looking...I give up. Please show me where to look.