Loose Grip/Tight Grip and Resulting Cueball Action

straightline

AzB Silver Member
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Man that got a lot of play. Intuition tells me anything you feel in your arm, was also felt by the ball and there is no arm feed back with a loose grip. Therefore etc...blah blah...

One thing about contact time. If that's so insignificant, how is it a phenolic tip can put a hole in the cueball?
 

dr_dave

Instructional Author
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Patrick Johnson

Fish of the Day
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My article in the June 1999 issue of Billiards Digest is a start. It describes one of the tests during "The Jacksonville Experiment" which was mostly high-speed videos of pool shots. Here's a link to a set of articles about those tests:

http://www.sfbilliards.com/Misc/jax_bd150.pdf
The last page in that article contains the following graph showing how the cue's speed drops on contact with the cue, even with a tight grip. Here's the relevant part of Bob's comment about it:

"...your hand...cannot have any significant influence on the ball during the brief tip-ball contact."

pj
chgo

jax.JPG
 

Biloxi Boy

Man With A Golden Arm
Thanks to Dr. Dave and Bob Jewett, and everyone else for your input. I have not yet sat down to study the information, but I am certain that it will advance everyone's knowledge.

For what it is worth: I have been stroking on the kitchen table and analyzing tight vs. loose grips. The difference detected is the effect on my wrist: a tight grip locks my wrist while a loose grip leaves my wrist fluid. Also, at the very end of my "loose grip" stroke there is a definite extension of my wrist. If I "hit" softly, my wrist extension is imperceptible, but when I hit for maximum effect, my wrist extension can be described as a "snap", and this is the point at which I would sometimes lose, or throw, an unwaxed cue from my loose grip.
 
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Biloxi Boy

Man With A Golden Arm
The above chart contains a marked anomaly which may be significant depending on whether or not it repeats in other strokes.

There is smooth acceleration in the stroke until the last six (6) measures before contact (mbc). At 5 mbc, acceleration drops for one measure and returns, approximately, to the prior speed (4 and 3 mbc). 2 and 1 mbc show deceleration just prior to contact.

Did this anomaly repeat? What was determined to be its cause?
 

Bob Jewett

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The above chart contains a marked anomaly which may be significant depending on whether or not it repeats in other strokes.

There is smooth acceleration in the stroke until the last six (6) measures before contact (mbc). At 5 mbc, acceleration drops for one measure and returns, approximately, to the prior speed (4 and 3 mbc). 2 and 1 mbc show deceleration just prior to contact.

Did this anomaly repeat? What was determined to be its cause?
The data was gathered by taping a paper ruler to the cue stick and focusing the high-speed camera on the ruler during the stroke. The bumps in the data you are referring to were probably transcription errors from the video of the ruler onto paper (or into a text file). The physical situation is very unlikely to have bumps like that before contact because they indicate very high accelerations. The details of the measurement are in the referenced article.

A more careful measurement is covered here, on Dr. Dave's site:
https://billiards.colostate.edu/faq/stroke/acceleration/
This video linked on that page shows the measurements of three different kinds of stroke: https://www.youtube.com/watch?v=LfzUvIzKJR4
Here is the plot from that more careful set of measurements that is for the stroke most like the one shown in the Jacksonville info:

CropperCapture[582].jpg

With more accurate data gathering, the "anomalies" go away.
 

Bob Jewett

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There are also some previous discussions of measuring stroke timing with an accelerometer attached to the cue stick. That method is a much faster way to do the measurement but has other problems.
 

straightline

AzB Silver Member
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Ok, scientists have intellectually enhanced common sense.
I'd like to see hi res data from a sensor placed in or on the tip and/or on the struck object and the ensuing spikes per loose, tight, and real tight grips.
 

Dan White

AzB Silver Member
Silver Member
Ok, scientists have intellectually enhanced common sense.
I'd like to see hi res data from a sensor placed in or on the tip and/or on the struck object and the ensuing spikes per loose, tight, and real tight grips.

Some are saying definitively that grip tightness cannot have an impact on momentum imparted to the cue ball during contact because of the short contact time and the fleshy skin. It makes sense, but unless someone did the experiment to prove it then it is just a hypothesis. Did anyone actually test this or is it more of a "must be true" kind of thing?
 

Bob Jewett

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Some are saying definitively that grip tightness cannot have an impact on momentum imparted to the cue ball during contact because of the short contact time and the fleshy skin. It makes sense, but unless someone did the experiment to prove it then it is just a hypothesis. Did anyone actually test this or is it more of a "must be true" kind of thing?
Two experiments were illustrated above. Did you not understand the results?
 

Dan White

AzB Silver Member
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Two experiments were illustrated above. Did you not understand the results?

Hi Bob. I didn't follow all the links so maybe I missed it. I'll look more thoroughly tomorrow. I just don't recall that "grip firmness" was a measured variable and if it wasn't then I'm not convinced that you can make definitive conclusions about it. I'm just saying that history is littered with scientists who were certain about what they believed until they actually measured it and surprised themselves. Again, looks like I missed it so I'll look more carefully when I have time.

Of course, I guess another option is taking it to the table and seeing what happens. I convinced myself that I cannot really get any more power by dropping my elbow during the shot compared to the pendulum stroke. Maybe I lose 1/2 diamond or 1 diamond after 4 table lengths. I suppose the same test could be done with loose vs tight grips and then go from there if it looks like something is happening one way or the other.
 

Ratta

Hearing the balls.....
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For years and years I played with a death grip. I'd say the cueball action I got was very similar to what I have now. The difference is that it's easier to get a smooth stroke forward transition with a loose grip. It's easy to jerk the stroke a bit with a tighter grip. Also there will need to be some elbow drop involved to get a full motion of the cue. The tight grip does help if you are extremely nervous. You can't really ruin the stroke by overtightening the hand, as it is allready tight.

The reason why tight grips are perceived to deaden the action, particularly when it comes to draw strokes, is that tightening the grip at the last minute tends to jerk the tip upwards a little bit, so that you hit closer to center than intended. That same phenomenon can also jerk the tip sideways and cause you to miss more shots. If your grip stays tight, or you tighten it in a controlled fashion, it will no longer apply.

I can also spin/draw the ball with close to zero follow through AND a death grip, if I wish. It's a specialist stroke that is all wrist and very little if any arm involvement. I was taught by a carom player how to do that stroke. It comes up very rarely, but can be useful.


Very delicate-and very correct point matey!
I ve "grown up" in a billiards room which was packed with national, european and world class carom players. I loved this synergy between "me" (or us) pool players who kind of invaded this room (bc the son of owner installed first two 9 footers....which was like blasphemy at teh beginning, lol).

To learn especially about the effiency using different bridges- and (how you ve also shown up basically) also how to use some finesse shots in the small areas by using almost just your wrist- very very insightful.

This was a fantastic opportunity. Was for sure some of the best times i have had in my billard life.
I also stand behind the saying: "Keep it simple"- should be always a thumb rule- but .... billiards is a sport of precision- and you need knowledge and a wide variety of technical fundamentals.
 

lfigueroa

AzB Silver Member
Silver Member
Personally, I don't get this whole A or B thing.

It should be what *for you* delivers the most accurate and consistent stroke. That's what's really important, not what gives you more action. Missing, but getting a lot of action on the CB, is not of much use. And equally important is speed control -- what gives you the most precise amount of speed control.


Lou Figueroa
 

Biloxi Boy

Man With A Golden Arm
You are correct about control. But the ability to control, from my prespective, is greatly enhanced by a thorough understanding of a subject. Knowledge is power.
 

ShootingArts

Smorg is giving St Peter the 7!
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Grip

Like many things, I played with grip strength long ago. The tightness of the grip didn't matter in pocketing the object ball or positioning the cue ball. Things were a bit different but once adjustments were made, I couldn't get a bit more spin with hard grip or letting the cue rest cradled in my hand, no grip. I played with a moderate grip for years, I don't even notice what I play with now. The same with stance.

The only difference between a soft grip and a death grip was that my arm got tired and sore strangling the cue stick.

There are many different ways to vary side spin on a cue ball. Testing hasn't been done but after decades of play I strongly suspect that it doesn't matter how you get there, the extreme maximum of sidespin you can put on a cue ball remains the same or very close to the same. Part of the equation is the grip strength between the base of the cue ball and the table. That stays the same regardless of other variables and may be the decider.

Hu
 

Bob Jewett

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The main effect on the hit of a tighter grip -- assuming you can achieve the same tip offset and stick speed at impact -- will be that the effective mass of the stick will be slightly greater. As I recall, it was about 1% for a typical grip due to the softness of the flesh of the hand, which keeps the majority of the weight of the hand from really participating in the collision.

(During the time of tip-ball contact, the hand doesn't have time to "wind up" to provide significant additional force on the cue stick. In contrast, as the tip compresses for about half a millisecond (0.0005 seconds) it is hard enough that the tip-ball force builds to around 100 pounds. That is from a compression of about 1-2 millimeters. Most of the compression of the stick is in the tip rather than in the ferrule, shaft, joint and butt, but those other parts of the cue also compress during tip-ball contact.)

So, let's suppose that by gripping really tightly you could get the hand to increase the effective weight of the cue by 3% instead of the normal 1% for a normal grip. Instead of that death grip, you could get the same result by adding 2% extra weight to the stick or about 0.4 ounces.

You could also get the same result by increasing the speed of the stick by about 1% with your normal grip, because speed is more effective than stick weight, percentage wise, for getting more spin and speed on the cue ball.
 
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