Push-pressure being exerted by the trail hand at impact

The physics of collisions for a full golf swing (without the need to overcome obstacles like grass to get to the ball) seems to have been studied and researched in depth, especially now with all the high-tech equipment. Dave Tutelman’s website is full of useful information to identify facts about the reality of the kinetics/kinematics (I’ve added the definitions at the bottom of this post) of the golf swing but is lacking in detailed anatomical instruction.

Check out the link below and note his statements that I have copied and pasted:

Design Notes - Physical Principles p4 (tutelman.com)

  • Square clubface and direction of clubhead travel: Right on! The equation assumes that the clubface is square to the direction it is traveling. If not (due to improper swing or a lofted clubface), a lot of the momentum will be transferred to sidewise motion and spin, instead of ball speed.

  • Center impact on the clubface: Right on! Every club has a “sweet spot” somewhere near the middle of the face. The equation above assumes you hit the sweet spot. If you miss it, you lose ball speed. I have seen estimates as high as 7% loss of distance for every half inch you miss the sweet spot.

  • Strength or weight of the golfer holding the club: Simply not a factor! If the golfer couldn’t convert strength and weight into clubhead speed, then there’s nothing that they can do during impact to increase distance. As we saw in the section on vibrational frequency, the clubhead is swinging free at this point, with little more connection to the grip than if it were on a string.

Actually, that’s an overstatement. The shaft is infinitesimally stiffer than a string. If you do something at the grip during impact, 1/10,000 of that effect will reach the clubhead while the ball is still there. But that’s all.

Note:
Kinetics, branch of classical mechanics that concerns the effect of forces and torques on the motion of bodies having mass.
Kinematics is the study of motion of a system of bodies without directly considering the forces or potential fields affecting the motion. In other words, kinematics examines how the momentum and energy are shared among interacting bodies.

Let me know when a golf scientist does a research paper on the difference between hitting and swinging. Two different protocols, two different applications, two different results. Studies on swingers assuming to give “evidence” for all golf swings is bad science. I understand that people like to study scientific research on the golf swing, but the scientists that are doing the testing need to understand these differences, and clearly they do not at times.

The cameras also become an issue with the rolling shutter distortion at times. Then you also have to understand that the outward centrifugal force has a straightening effect upon the shaft… like a rock on a string spinning around. The faster you spin it, the tighter the string gets. So this also can mask or hide what we see visually…the load of stored energy or flexation in the shaft. In other words, the shaft that is being stressed backwards isn’t going to be visually bent backwards as much when traveling at higher speeds because of the stretching effect… (rock on string). However the stored energy in the shaft from the clubhead accelerating tangentially is there but sometimes not seen due to both that and the stiffness of the shaft.

The bottom line is that everything you are speaking, and the studies are coming from a swinging ideology and not a hitters.

I’m sure the scientists are well aware of rolling shutter distortion and they aren’t just using cameras, but also other high-tech equipment such as strain gauges attached to the shaft to measure the flex and droop in golf swings.

Tom Wishon: Tom Wishon is a 40-year veteran of the golf equipment industry specializing in club head design, shaft performance analysis and club fitting research and development .

Forum members might find his post/article quite interesting:
Tom Wishon post to Spinetalk (tutelman.com)

Note what he says:
“From all of this, we do believe that the only possible way that a golfer can have the shaft flexed backward in what we call a “shaft lag” position is if they somehow were able to reach impact without fully releasing the wrist cock angle - if this were possible for the golfer to do this without injuring themselves and without missing the ball, the fact that the arms still contain a fair amount of energy to keep their velocity would allow the possibility of the shaft still being flexed a little backwards. I’ve mentioned before that the only shot in the game I can think of this being possible is one of Tiger Woods’ stinger shots that he can hit with a long iron or fairway wood to keep the ball really low.”

If I interpreted above using TGM terminology, maybe shaft lagging flex could occur if the golfer was able to keep his arm speed high approaching impact by only partially releasing PA2 angle late in the downswing (creating lots of forward shaft lean at/through impact). Really, there isn’t much evidence at all that proves that golfers can retain lagging bend into/through impact although I suspect some very strong long drivers might have that capability.

With regards swinging versus hitting , it is difficult for me to understand the definition of hitting without making an assumption that it is ‘active wrist torque’ . A ‘Swinging’ release (imho) is the angular acceleration of the club using torque created by eccentric forces applied via the hands on the grip (see 2nd video link I posted below and the ‘In Plane Moment of Force’).

I am assuming Bobby Jones had a swinging technique with little active wrist torque (ie. hitting) in his downswing.

For any golfers using some ‘hitting’ in their downswing, I can imagine they are adding wrist torque to augment a swinging release to try and increase clubhead speed, but this will need to be timed perfectly otherwise one can get peaking of clubhead speed too soon or too late with non-optimal alignment of the clubshaft at impact.

Therefore swing-hitters are a possibility, but I cannot imagine a pure hitters golf swing.

It is worth forum members to view these 3 videos by Dr Sasho Mackenzie who is a world renowned biomechanics scientist (with a handicap of 1.6).

Intro to Club Kinetics on Vimeo

In-Plane Couple and Moment of Force During the Golf Swing on Vimeo

Linear and Angular Work during Downswing of a PGA Tour Major Winner on Vimeo

Interesting, because this is exactly what I teach here at ABS. You can do this without injuring yourself! Study, Hogan, he did this incredibly well. Holding vertical wristcock through and beyond the strike…
hogan5 copy 2

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Yes, it may be possible but is a low stinger what you are trying to teach? Wouldn’t you regard a more complete release of PA#2 as being very important for the generation of clubhead speed?

PS.
Centrifugal force (the term is not well defined in physics) can be thought of as the pull by the ‘rock’ on the hands via the string. It is the equal and opposite force (Newtons 3rd Law) to the ‘Centripetal’ force acting on the ‘rock’ (via the string) by the hands. Both are involved in the increased tension in the string but cannot angularly accelerate the rock by themselves. One needs torque to create rotation but ‘Centripetal’ force sustains it.

It’s possible. It’s not “maybe” possible.
If I take the club back 24 inches, I certainly can accelerate that clubhead to the ball and hold shaft flex. Anyone want to bet 10K? I’ll take your money really quickly!

I’m not sure exactly what the low stinger is. Have heard of it or a shot that Tiger hits but I haven’t studied the mechanics of it… or specifically what that means or entails.

PA#2… are you talking Golf Machine terminology? The vertical hinging of the wristcock I assume? If that is the case, then I would disagree. Fully releasing the wristcock is NOT something I teach. It’s actually at the core of why I left the TGM swinging protocol and moved into proper hitting… and not the TGM version of hitting with promoted an active straightening of the right arm through the strike. Both the right arm straightening and the full uncocking of the left wrist are accuracy killers and extremely problematic and completely unnecessary.

Study Hogan…

Does not fully uncock the wrists downward and keeps the right arm rigid from P3 to P4.

If you want to argue against the methodology of the greatest striker of all time… then I don’t know what else to tell you. Hogan was right as I see it… and he was not a short hitter. Peter Senior had the same action through the strike and was also a long hitter in his prime.

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Tiger Woods ‘Stinger’ explained by himself.

How Tiger Woods’ stinger has evolved over his career | Instruction | GolfDigest.com

Here is Tyler Ferrell theorising on his explanation of the ‘Stinger’. The shaft doesn’t look to have lagging bend to me, maybe straight or slightly forward bend. There is a close-up of the clubhead and the lower section of the shaft using high speed camera so shouldn’t have any significant rolling shutter distortion.

https://www.youtube.com/watch?v=6VNLGKjYvYk

Tiger here looks like he may be over accelerating and losing shaft flex. Most pros do this and compensate with stiff shafts.

But again, I can’t rule out some camera distortion. An iphone put on slow motion will appear to be getting accurate captures, but will still have rolling shutter distortion issues.

Unless we know for certain it was shot with a global shutter camera… we can expect some issues.

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Agreed! I wish Tiger would go back to that driver with the steel shaft. He seemed to rule with that club.

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