Finney

[Jeff Martin]

finn.PNG

Nope, I haven't heard back, but didn't really expect to. They are smart guys and no doubt figured out when they got my email that you are up to your old tricks, creating acrimonious pissing contests in public while invoking their names, and have zero desire to get in the middle of it.




Jeff

[Richie Hunt]

Reminds me of the 'a slower rate of closure will cause more hooks' claim. I asked a lot of scientists who agreed with me...it's bunk as the club face is still closing so the gear effect would not produce an opposite result. And those scientists don't know where that conclusion that it will cause more hooks came from because it didn't come from them.





3JACK

[Jeff Martin]

finn2.PNG

I agree, Kel should take that video down, because you are misrepresenting it in order to discredit him. He says nothing about the "snap" initiating the downswing, yet clearly you are telling folks like Kwon and McGill that's what he means. Knowing Kel, he couldn't care less what you or they think, so I doubt he'll do anything except laugh when he reads this.

Also, the video wasn't created by me, whose views we are debating, it was created by Kelvin. Get your facts straight.

Kelvin's views are explained in detail in his articles. If folks are too lazy to read them, they can't claim to know his views.




Jeff

[Jeff Martin]

finn3.PNG

Shut up, Mike. Seriously, nobody gives a shit about your thoughts on this or any other topic. Why don't you go check on the Snickers inventory?




Jeff

[Max Prokopy]

Jeff and any others still reading,

I summarized my opinion on some of the issues. I have many more thoughts but here is the "short" version. I apologize for the length but if we are to reconcile these 2 successful and great minds, we gotta be pretty careful. This is simply my opinion but you'll note much congruence to the swing ideas on your forum and in Kelvin's articles.

On the spinal coupling: I think this appears all over athletics. People think this concept of spinal coupling stands in some stark contrast to Stuart McGill or other spine experts and that’s simply not the case. The trouble is that the coupling and potential force production are no small thing to measure, model or quantify. We have very subtle motions but they occur right near the center of mass. That's tricky.

The core musculature and other muscles which attach to the spine often do so on multiple vertebrae. When we talk about “core stability” that is simply a widely dispersed co-contraction of these muscles, a bit like the guy wires on the mast of a ship. Lats, psoas, obliques, rectus, multifidus, erectors, longissimus, etc. These all have multiple spinal attachments. So when the spine rotates or side bends or extends, numerous small changes in length take place. Ligaments and fascia will also change length and these tissues have elastic properties (they can stretch and rebound). This is one reason EMG is so incomplete. This is also how the spine itself may lack apparently meaningful elastic properties but still be an "engine."

When these tissues are stretched due to motion, a source of potential energy is created. Power from the hips can add to the motion and potential energy. The “ultimate” scenario is a pulse or burst of tension at the core whereby the entire area stiffens for a brief moment. (This is akin to the pulse when you are about to punch a punching bag – a moment of stiffness will “brace for impact.”)

The pulse has several key outcomes: first it helps distribute load over multiple discs. That is surely a good thing. I don’t know a single spine expert that would want all motion to come from a couple areas while the others are frozen. If we pack all that velocity and force into 1 or 2 joints, it’s a time bomb. Perhaps the "modern pitching mechanics" are doing this by either artificially limiting spine motion or encouraging deeply asymmetric tissue changes.

Second, the stiffening will turbo-charge the elastic rebound of the stretched muscles. McGill’s pulse pull-up is a simple way to visualize this (I linked that video previously). Many things work in synchrony to create a stiffness that helps force transfer…the whole becomes larger than the sum of the parts. Some of the force is surely emanating from the spinal attachments themselves.

Thus, the side bend coupled with lordosis provides this feature. Not only can it encourage counter-rotation at the pelvis, but the core musculature is stretched to increase potential energy. My intuition says this move may indeed be primary (it occurs first). Assigning an individual power output to this phenomenon alone? I would question that because the pelvic and upper spine counter-rotation create rapid downstream stretch-shorten cycles which react very quickly. The glutes can behave in this manner – the glute is stretched as the CoM lowers- most recognize that as a major power source in all athletic movements. Kelvin's own articles highlight how subtle the changes are - subtle and yet worthy of creating large potential energy stores via the SSCs.

The glaring warning in all this is again that coupling motion sure as heck better be well distributed. Concentrated loads may elicit brief power advantages but are long-term nightmares.

The major side-bending capacity of the spine is from the thoracic spine. The thoracic spine is in flexion in golf swings, especially your older folks. When one side bends and flexes away from the target, that part of the spine will rotate AWAY from the target.

Long story short: we have coupled motion of lumbar lordosis plus side bend away from the target. That should induce the pelvis to rotate towards the target. We also have the t-spine side-bending away from the target but it’s in flexion and thus rotating away. So-called X-factor? I think so! Potential for power? Yep! But we better be darn sure we have some symmetry in the deep core muscles and spinal alignment. We are about to concentrate some serious forces at the junction of flexion/extension.

I can tell you from experience many people don’t have this symmetry – the lat or psoas is tighter on 1 side so the spine engine has an uneven activity pattern. That jams the disc nucleus which leads to all kinds of possibilities. The inventor of ART (Dr. Mike Leahy) had a great presentation on a pitcher with elbow issues and asymmetrical internal obliques. He released the right obliques and t-spine was restored and the elbow was gold.

I'll finish this diatribe with my opinion that DNS and Dr. Pavel Kolar are at the forefront of the next level of application of the spinal motion, stability, and application to sport. It is worth looking into and there is in fact a DNS golf-specific course in St. Louis in September. I will be there for sure, ready to learn and share.

[Jeff Martin]

Thanks, Max. Informative post, and it was the furthest thing from a "diatribe". This paragraph identifies the source of the "snap" that Kelvin describes in the video, which can be observed in Jaime's high-speed videos and quantified in Jamie's rotational velocity graphs:


Long story short: we have coupled motion of lumbar lordosis plus side bend away from the target. That should induce the pelvis to rotate towards the target. We also have the t-spine side-bending away from the target but it’s in flexion and thus rotating away. So-called X-factor? I think so! Potential for power? Yep! But we better be darn sure we have some symmetry in the deep core muscles and spinal alignment. We are about to concentrate some serious forces at the junction of flexion/extension.


When the spine decouples due to PPT, the induced axial torques acting on the pelvis and thoracic spine are released and the spine reverts to its natural alignments: the pelvis slows, stops or even reverses and the thorax accelerates. I posted this yesterday in another thread:


jamie.jpg


In Jamie's swing, whatever "snap" is applied to the thorax appears to occur after impact. I'm curious to know if other players disengage spine coupling earlier and, as a result, are able to use the "snap" to accelerate the thorax through impact, and, most importantly, whether there is any advantage to doing so. My instinct is, if Jamie doesn't do it, than probably not.





Jeff

[Max Prokopy]

Thanks Jeff. I can guarantee you McGill would approve of the decoupling because you'll also experience a simultaneous relaxation of the core muscles. They pulse just before impact but quickly relax.

In fact McGill states over and over that the best athletes are the ones who relax the fastest. Barry Sanders comes to mind, as does Usain Bolt.

As for golf, if you know Shawn Clement, I think you'll see this early decoupling:



Also here is Jack where it seems there is a decouple pre-impact. I could be wrong it's not so easy to tell.

nicklaus_profil.jpg

[Jeff Martin]

Also here is Jack where it seems there is a decouple pre-impact. I could be wrong it's not so easy to tell. nicklaus_profil.jpg

Very interesting about Jack. He makes what looks like a goat hump, but maybe it is just early PPT. Something to ponder!!!


jack.PNG




Jeff

[Jeff Martin]

stu.PNG