Physics of the golf swing

Public Forum—Concepts in Advanced Ball Striking
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Hi, i dont know if this is posted in the right thread. But i found this guy [https://www.youtube.com/channel/UCuIJ13JFvzvdMQPwjG6UEWw] on youtube who talks alot about the physics of the golf swing, also having some videos on Pete Cowen who also talks about linings natural forces to work for you.

This is completely the opposite to what John is talking about, they say you should slow down arm and hands through impact to release the club with minimal compensations.

Dont saying anyone is wrong/right. But im a bit lost, both seem very convincing

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That requires a stalling of the hips too…like bubba watson.

We dont do that here. We maintain our hip action through the strike because we accelerate the club past impact. Orbit pull…vs. stall and throw. Very general description here…

Again, physics of a golf club (science) vs. Biomechanics of a golf swing to produce desired pressures on a golf shaft (truth).

We cant swing a club the way science wants us to (swing robots are not humans) unless youre gonna spend all day on the range maintaining that timing. My humble experience anyway…

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I agree with 72holeouts, if we put 5 Physicists in a room all will disagree with the interpretation of storing and releasing of energy, even though they know it happens. While I am new to ABS, it is already a superior cause and effect the closer I get to SS and the stronger increasing correct arm/hand speed at the bottom of the swing. I believe that Kinesiology (science/study of motion) when combined with the physics of releasing stored energy is both efficient and repeatable in the ABS Golf swing…

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To answer one of the OPs questions, hand speed does slow down approaching impact usually. ABS teaches to accelerate the club head beyond impact. These are not mutually exclusive IMO.

I’m not sure if ABS specifically teaches that hand speed must accelerate through impact, would defer to Lag and his students. They definitely teach you most apply force to the handle through impact and beyond.

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Since we are not throwing the hands at the ball and are ideally rotating with the torso then yes, the hands will be accelerating through impact if we are also holding shaft flex.

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Today’s video showing that we can bring an energy (kinetic) stored clubshaft into impact.

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I feel like the hands are accelerated for sure…but it is in sync with the pivot. The faster i accelerate from P3, the more my pivot has to engage…that in turn forces my levers to go…boom pow

I never feel like i use my hands actively though…pivot, pivot, pivot…module/drill 1 until your hands bleed. My humble $.02

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My perception is that when I throw the hands at the ball the feeling is fast. When I focus on using the turning of the torso/ Left shoulder to pull the arms/hands then the feeling is slow compared to the throwing action. Ball goes the same distance but the pulling action from the top of the transition FEELS slower. My hands are aggressively holding the shaft in ulnar deviation through the strike and orbit pull. This latter part feels fast.

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Played well yesterday, hit 14 of 16 fairways. Always longer with feel of L shoulder rotating level and through…almost feels like it leading the charge to me.

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That would be the correct application of shoulder rotation.

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You asked a question and the thread was locked before I answered

Who is this “golf scientist”? Has he ever tried to swing a club in a way that would hold shaft flex? Where are the studies that show how much force is being applied to a golf ball (both with and without the intent of holding shaft flex)?

I’m not naming the scientist for you to start ridiculing him like your ABS posters tend to do me and others who question your claims.

Just do an experiment yourself and stick the butt end of a driver in a vice and hang enough weight on the club end to make it bend 2 inches (which is a lot and not even JE can claim to accomplish that feat). It will probably be even less than 4lb-force probably more likely 1.2lb- force per inch of deflection.

The fully driven clubhead will typically exert a force on the ball of approximately peak 2000 lb-force to make the ball move at approx 100 mph.

So the the exaggerated 4lb-force (more likely 2.4lb-force ) to make a 2 inch bend will create a 2004 lb-force . An increase of 4/2000 = 1/500 which is a miniscule increase which will have a trivial effect on club/ball impact.

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The guy in the video doesn’t provide a very detailed explanation. For a swinging action, the slowing of the lead arm is caused by a properly timed kinematic sequence in the downswing (not by purposely trying to slow the arms down).

In the downswing , the pelvis rotates first, then thorax (chest) , arms, club.

The pelvis moves first, then there is potentially some transfer of energy from the pelvis to thorax , then from thorax to arm, then arm to club via the wrist joint. As well as some energy being transferred through each segment , there are muscle contractions within each segment that can add to their movement,

When the pelvis transfers energy to the thorax , the pelvis will slow down while the thorax speeds up.
When the thorax transfers energy to the lead arm, the thorax will slow down while the lead arm speeds up.
When the lead arm transfers energy to the club , the lead arm will slow down while the club speeds up.

Here is a good analogy
A father is running with his child on his shoulders , then the child jumps forward off his fathers shoulders. What do you think happens?
The child is now moving faster than when he was on his fathers shoulders, while the father has slowed down because the child pushed him backwards.

The same thing happens in the golf swing:
The rotation of the pelvis is carrying the thorax/arms/club at the start, then the thorax pushes off the pelvis , then the arms push off the thorax, then as the club releases it pushes off the lead arm.

The added movements of each segment are caused by the contraction of the muscles that can move/rotate each body segment.

The pelvis is moved/rotated by using the legs to push against the ground plus there are pelvic girdle rotator muscles that can be contracted to help in its rotation.
The thorax is moved/rotated by the contraction of the internal/external oblique muscles.
The arms are moved by the shoulder girdle muscles.

The total affect of the above creates the necessary forces on the club via the hands to speed it up, but as it does so, the ‘club/hand/wrist unit’ also pushes against the lead arm slowing it down.

The above is a very simplified explanation.

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I think again… what you are not considering… is the CF pull on the shaft that stretches the shaft lengthwise at high velocities. The heavier the club, the more longitudinal stretch there will be also.

So even when the shaft is pinned back… .holding shaft flex, it is visibly hard to see because of this masking effect created by the stretch.

This is why a lot of the armchair observers insist it isn’t happening (holding shaft flex) when in fact the kinetic energy is still stored in the shaft… despite it being pulled lengthwise by the weight of the clubhead at higher velocities.

It’s very real stuff.

If I use a passive hand swinger’s release, I feel no pressure in my right hand (laterally)… you can look at VJ Singh and see his right hand is falling off the club at impact. His release is pure CF throw… an obsessive ball beater to keep this timed.

Now if I use a hitters release, applying a quick rotation of the shaft past the third parallel … just before impact… with the hands, via forearm rotation, and an equally quick and aggressive torso rotation, this puts a massive load of pressure into my right hand.

I am sure than any competent measuring device would pick up on this… because it IS REALITY!

I don’t need someone or something to tell me there isn’t a difference. It’s like me thumping you on the head with a 2 x 4 and a scientist saying "there is no proof of that actually happening…

We won’t be going down that road here.

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"I think again… what you are not considering… is the CF pull on the shaft that stretches the shaft lengthwise at high velocities. The heavier the club, the more longitudinal stretch there will be also.

So even when the shaft is pinned back… .holding shaft flex, it is visibly hard to see because of this masking effect created by the stretch.

This is why a lot of the armchair observers insist it isn’t happening (holding shaft flex) when in fact the kinetic energy is still stored in the shaft… despite it being pulled lengthwise by the weight of the clubhead at higher velocities."

Only you can understand the above because it makes no sense in the language of physics that I am aware of. Potential strain energy is stored in a flexed shaft, not kinetic energy.

One thing you might be correct about is that ‘active musculature forearm rotation’ has been shown (in golfing models) to increase clubhead speed when applied just before club horizontal (I assume that is third parallel).

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Actually , the forearm torque is applied quite early when the lead arm horizontal in the downswing. The graph below shows the optimisation of a golfer model to optimise clubhead speed and matches the movements of a real golfers swing (from torso upwards).

You can see that even in this ‘swingers’ type golfing model that M_Torso (which is the torque of the upper torso) has to increase into impact. The forearm rotation torque (M_Arm) happens from lead arm horizontal and ramps up to a maximum just past club third parallel, then drops off to zero by impact.

I don’t expect JE or many other ABS followers to understand this but maybe others will.

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How is this kind of statement helpful? Do you think we don’t understand basic body movements?

I like the graph you show. Now, to understand how ABS functions, the last point of the graph you need to be applying acceleration through the “orbit pull”. In other words, as the shaft is being rotated into the ball the lead shoulder and torso are picking up speed and applying force to the club.

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Spot on, and something I’ve been pondering for a spell. That pressuring back into the trail hand would certainly be a reason to want 3 or more right hands I would think.

I remember on the old site you mentioning post-impact acceleration into PV5 was like passing a baton forward- when the hit into the ball merges with a pivot motor to continue accelerating.

But maybe there’s another baton too, a baton that’s passed backward, called pressure, into the trail hand before the other baton is engaged by accelerating forward.

Just something from my experiences that I found interesting sensing 2 batons.

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The pull you are describing as the CF pull, does this mean the outward pull of the club head on the shaft of the club?

If so, what you are saying is that the hands are still applying a force to the shaft which would bend it back (flex it), but because the club head is also exerting a straightening force, the hands force cannot be seen because the shaft doesn’t appear bent back (or is bent back very little)?

Do I understand your statement correctly?

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No, JE and some ABS posters don’t seem to understand the basic kinetics involved when the clubhead releases or the physics involved in the flexing of the shaft. From the same article where that graph originated from are these other graphs.

image
image497×679 109 KB

You can see that the angular velocity of the torso and arm is decreasing (ie. the slope of their graphs is getting flatter approaching impact). This means the torso (and the lead arm) is slowing down even as the golfer is increasing his pivot torque. Therefore, the golfer might be feeling as if he’s exerting more effort in rotating his torso but it’s actually slowing down (feel isn’t real). All the while the torso and lead arm are slowing down, the club is accelerating.

Here is the graph showing how the club shaft flexes during the downswing.

image

Note that by impact , the shaft is in forward flex bend not lagging bend.

Compare what I’m showing you with the vague abstract comments of Range Rat which makes little sense to me but maybe you can decipher it into some understandable form.

"That pressuring back into the trail hand would certainly be a reason to want 3 or more right hands I would think.

I remember on the old site you mentioning post-impact acceleration into PV5 was like passing a baton forward- when the hit into the ball merges with a pivot motor to continue accelerating.

But maybe there’s another baton too, a baton that’s passed backward, called pressure, into the trail hand before the other baton is engaged by accelerating forward."

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“Now, to understand how ABS functions, the last point of the graph you need to be applying acceleration through the “orbit pull”. In other words, as the shaft is being rotated into the ball the lead shoulder and torso are picking up speed and applying force to the club”

Can you show me a force diagram showing how the ‘orbit pull’ is applying force to the club?