Recently I debated with a few science minded folk who have believed wrongly about the affect of acceleration on the golf ball and the ball flight. The modern scientific belief is that acceleration has almost zero effect on ball flight. The presence of acceleration through a 2 cm zone of 1/4000th of a second could not have enough acceleration in such a short interval that it’s insignificant. The following is why I disagree:
Bringing up the hockey slap shot again because it is exactly what we want the golf shaft to do. Hockey players hit the stick on the ice and drag it to stress the stick backwards into the puck, having the stick release when the puck is hit. This is how it is taught, ask the scientist what they think of that. If acceleration does not do anything then why would slap shots be hit this way. To think of how dumb it is imagine them saying that mass did not have an effect.
Does a 2,000 pound car hitting a wall do as much damage as a 10,000 pound car hitting the same wall if they are going the same speed. Of course not, obviously. Same thing as saying does a car staying at 30 mph and hitting a wall do as much damage as a car that is in the middle of accelerating from 0 to 60 and hitting the wall at 30 mph. Of course not, obviously. Think of flooring the car from 0 and being pushed back into the seat then switching gears. Clutch is pushed in disengaging the engine which is the force. You are thrown forward in the same way that the club shaft is thrown forward, hopefully when it comes in contact with the ball. That feeling of being thrown forward is what the ball feels, just different amounts. Trevino like a corvette shifting gears and Hogan like a Lamborghini. Try and move when in a fast car flooring it, difficult to move much and that represent the club face. Then think of staying at 30 mph and pushing the clutch in, you are not thrown forward and can move anywhere you want. Dumb argument, anyone that does not think acceleration has an effect minds well take a boat ride the edge of the earth. Funny they still thought the earth was flat while the moon was there in front of them. Same thing, wrong.
The science guys who think acceleration doesn’t matter are simply not looking in the right place, and they are basing everything on the measurement of 2 cm while the ball is on the club for 1/4000 of a second. In that short a sample, acceleration is hard to detect. Like a dragster going from zero to 200 mph and measuring 1 foot of it’s travel somewhere on the track and then using that data to suggest the car is not accelerating.
Another problem is the accuracy of any measuring device looking across a 2 cm interval. I suggest above than measurements be taken 2 feet before, at impact, and after impact. Measure the mass of the club and the ball, COR and that will get us a pretty good idea what is going on at impact. It basic common sense stuff. The less the clubhead slows down the deeper the compression into the golf ball… the more the ball will penetrate in flight, and the more feedback the player gets.
If you are holding shaft flex, then you are hitting it with the entire club, not just the weight of the clubhead, and the body can actually get involved in resisting the forces of impact if a proper cohesive body tension is in place.
Acceleration is not about hitting the ball farther, it’s about controlling what the ball does consistently. This is why a lot of very long hitters are horrible golfers.
I absolutely agree. Those that say it doesn’t matter, the ball is long gone, most likely develop a swing that hits at the ball and not through it. Really dangerous thinking that leads to a very real physical manifestation.
Where I get hung up is in the words used. Saying we resist the forces at impact implies to the unitiated a slowing down of the swing. How about thinking about hitting through impact, using the forces of impact as a physical cue to accelerate faster so you’re going faster after impact into P4.
Trevino talked about using mass rotation instead of muscles to power through. I like that idea.
No doubt about that. I don’t think that anyone would produce acceleration of the club-head when it suddenly picks up and gets dragged down by the mass of the ball during impact. The club-head slows down, even for an advanced ball striker. For that reason I think that it is better to consider (and measure) force than acceleration. The force may be there at impact, but acceleration is ruined at impact by the collision with the ball.
I don’t think that is necessarily so. Isn’t that why we play heavy gear? The more mass the less effect the ball collision will have on it. You guys are welcome to post on my thread. The antiABS crowd is out in mass. 
I found this graph on that site. The brown-yellow line shows the clubhead-speed, and it plummets at impact. A clump of lead-tape on the clubhead and a sound hitting action won’t change that much.
i think the whole point is that if you intend to try to keep the club accelerating post impact (whether possible or not) then you will swing differently than if you intend to just dump and roll.
Thinking about this, I am guessing that discussing this in terms of just acceleration isn’t quite good enough. I suspect that:
The bad golfers’ clubhead comes into the ball with some acceleration, but with decreasing acceleration. This is often mislabeled as “deceleration”.
The decent golfers’ clubhead comes into the ball with constant acceleration.
The advanced golfers’ clubhead comes into the ball with increasing acceleration. This is often underestimated as simply “acceleration”.
I took some liberties with labeling the various types of golfers, but I hope it is clear what I mean.
This graph would show the bad golfer’s and the advanced golfer’s clubhead speed vs time, from transition to impact. In this case they reach the same clubhead speed, but have a different way to get there. The difference should be measurable before impact. The decent golfer would produce a straight line from the origin to the endpoint.
It’s always an interesting discussion,
but no need to get lost in semantics…
A club slowing down…
coming it at a constant velocity
or speeding up
If the club is speeding up, there must be a source of power to do that.
To hold shaft flex, the club has to be speeding up.
And to hold shaft flex, the grip of the club must be worked counter clockwise in pressure against the weight down in the clubhead… this is what stresses the shaft backwards.
If this action is happening through the impact arena, then a player can hold shaft flex.
The club doesn’t need to be traveling 100 miles an hour to do this.
I can hold shaft flex chipping the ball 15 feet.
It becomes more difficult to do this at higher speeds… but it’s doable with good technique and strength.
A shorter backswing with a heavier head helps the cause significantly.
The quest to do so is two fold.
There is the physics of impact where an accelerating club will aid in resisting the forces of impact… and this also helps in
off centered strikes…
Then there is the great added pressure in the hands themselves if one is holding shaft flex… the counter clockwise rotation of the grip against the mass of the club.
Since golf is a game of feel, anything we can do to increase the pressure and feel in our hands is beneficial.
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Yes, and to get the grip working counterclockwise, you would have a late rotation of the left forearm into impact (among other things…)?
Waj.
An intersting posting from someone who has nothing to do with ABS…
"Constant swing speed is only a moment in time. You are either accelerating or decelerating.
The ideal impact alignment has a left hand leading the club head through the ball and - the famous forward shaft lean - shoulders and hips that are still turning, a heavy right hand on the club - and with no freewheeling going on. The only way to produce and maintain such a form is by accelerating.
The flip and the stall and loss of club head lag - and perhaps even loss of club face control - starts to develop as soon as the acceleration stops. And the acceleration stops as soon as this develops. It works both ways, and the impact alignment shows whether a golfer is accelerating or decelerating through the ball.
To plan for it to happen right at impact leads to high maintainance swings at best. But usually a lot worse since most people who plan for max swing speed at impact are hackers who start to decel a long time before impact.
This has nothing to do with saving or spending the good stuff. It has to do with having a technique that enables you to power the swing for a shorter or longer part of the swing."
Do I believe in it? Of cource:
Chris
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Who is that quote from Chris?
Would it be accurate to say that without active forearm rotation one cannot impart flex in the shaft in the downswing just prior to impact?
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I think you can accelerate prior to impact a variety of ways, using any number of muscular combinations. Forearm rotation seems to be the most efficient way to do this, assuming you have the mass behind it. IMHO
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Thanks for the reply. I was just curious whether one can impart flex in the shaft by using just forearm rotation by itself.
I know that Lag has stated here many times here (and in the BBG videos) that active forearm rotation in conjunction with torso rotation really gets the shaft flexed just prior to impact and beyond. Of course as you correctly pointed out, the key is acceleration - especially at around P3 all to way to P4.
Cheers.
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Rotating the forearms just prior to impact is precisely what we train for in module 1. We strengthen our muscles by doing thousands of reps. 
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