There are only two strokes in pool?

Bob Jewett said:
As you see, this question caused some confusion. Most people can't distinguish between acceleration and velocity.

Whether the stick is accelerating at the time of impact makes virtually no difference to what the cue ball will do on most shots. As mentioned above, if you want to play with minimum effort, the best time to hit the cue ball is when the stick is moving at top speed. That is exactly when the acceleration is zero by the definitions of acceleration and velocity.

Whether that's the best time to hit the ball when you take other factors into account is another matter. For certain special shots, something else is required. The best example I can think of is when the cue ball is 1/4 inch from the object ball and you have to shoot straight at it. This needs to be hit with a severely decelerating stroke, and there are several standard techniques to achieve this. Jump shots are another example where deceleration may help you to not double hit or trap the cue ball.

To get maximum power, it may be best to still be accelerating when you hit the ball, but this is only because if you hit the ball at peak speed your stroke might be too long for accuracy. This depends on the player's skill and technique. Watch videos of power nine ball breaks.

For standard shots, some players seem to use constant acceleration, some hit the ball at zero acceleration and others hit the ball somewhat before the peak velocity so there is still some acceleration. You can make hand-waving arguments to support each of these techniques. Unfortunately, no professional sports kinesiologist has looked into this, AFAIK.

There are several articles here: http://www.sfbilliards.com/articles/BD_articles.html (look for "stroke") about various aspects of strokes including a list of types. Dr. Dave has some good discussions and measurements on his site as well.
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Thanks Bob.
 
3RAILKICK...The speed of the backswing has no bearing on the speed of the forward stroke. In fact, if you try to backswing quickly, you will likely miss where you're aiming on the CB, due to a poor transition from moving your cue backwards and forwards.

Joey...There is only ONE stroke. It is used many ways, at different stroke speeds...but then you already know that! :grin:

Scott Lee
www.poolknowledge.com

3RAILKICK said:
Joey-

Clarification please.

If the 'speed' or 'pace' of the backswing is the same as the speed or pace of the forward stroke-is this 'swing' of a contant speed and therefore without acceleration? Is that what you are referring to?
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Bob...Most of the time I will agree with you, but I have to disagree that you have to use a decelerating stroke to legally strike an OB that is very close to the CB. Stop by the BCA booth this summer, at the trade show, and Randy or I will show you how to accomplish this. It is a specialty stroke, but it does not REQUIRE a decelerating stroke speed.

Scott Lee
www.poolknowledge.com

Bob Jewett said:
Whether that's the best time to hit the ball when you take other factors into account is another matter. For certain special shots, something else is required. The best example I can think of is when the cue ball is 1/4 inch from the object ball and you have to shoot straight at it. This needs to be hit with a severely decelerating stroke, and there are several standard techniques to achieve this.
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Scott Lee said:
Bob...Stop by the BCA booth this summer, at the trade show, and Randy or I will show you how to accomplish this. It is a specialty stroke, but it does not REQUIRE a decelerating stroke speed.

Scott Lee
www.poolknowledge.com
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Just so you know, Scott, Bob is one of the best I have ever seen at this shot. You may have a different technique or you two are saying the same thing in different ways, but Bob know this from experience.

Thanks to all for sharing their knowledge.

Dave
 
Possibly Dave...but I am reading that Bob says this shot HAS to be hit with a decelerating stroke, and I'm saying it does not (but could be).

Scott Lee
www.poolknowledge.com

12squared said:
Just so you know, Scott, Bob is one of the best I have ever seen at this shot. You may have a different technique or you two are saying the same thing in different ways, but Bob know this from experience.

Thanks to all for sharing their knowledge.

Dave
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elvicash said:
DoubleD I think you are wrong but i cannot prove it. The Jacksonville experiment executed by some great players and other pool freaks has a lot of knowledge of exactly what happens at the point of impact. They were limited by having only a high speed camera no accelerometers or any other tools so they experimented visually.

They found that impact lasts about 8/10,000 and quality of player/stroke did not greatly increase that time. I do not know that they videoed much of weaker players as they had great pool and billiards players. I do not have a link to it or the writeup but Bob Jewett was a part of it.

I think there are at least 3 strokes in pool accelerating at and thru impact, constant speed thru impact and declling before and thru impact.

They key points to what happs to the cue ball are cue direction, CB/tip location, velocity.

Those items are a given what I think is also critical and are the great seperators are the player controlled items such as bridge quality, grip/cue control, power and acceleration. These secondary items are all extremely minor in effect on the ball but I think are important as well.
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Actually what that experiment did show is a stroke that is not accelerating at the point, or up to the point of impact, reaches its maximum velocity and coasts a bit before hitting the cue ball. This means the cueist needs to generate the speed in less time, and presumably with more effort, than a player who accelerates up to the impact of the cue ball. For me this explains why players such as Shane Van Boening, Ronnie O'Sullivan and Steve Mizerak are able to produce more results with less effort on their stroke.
 
bdcues said:
Would not a kill shot be a deceleration shot? Or do you think the cue is accelerating the entire time?

Bob Danielson
www.bdcuesandcomix.com
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That's not my understanding, bd. The kill shot is really just applying draw to the CB at a speed so that it is scrubbed off on it's way to the OB. To get the required draw action you really need to be accelerating through the cue ball. That's how I understand it anyway.
 
different stokes for different folks

This is only my opinion I think everyone has like four or five strokes accept the break but when talking about accelerating and decelerating I think that when hitting the ball with stun or draw or force follow these are the different strokes we use its the speed at witch we hit the cue ball that changes from shot to shot and then being able to be aware of changing back and forth from one stroke to another. This old war dog I used to play with he told me that before every shot I needed to pause and look at the shot to give my brain time to make a plan were I want to hit the ball how and at what speed and to prepare for this shot." Take the practice stokes with purpose". He told me and he's right.So I am for more than two strokes for sure.I would how ever love to see a great scientific out look on how we do this.It's a big part of sports science that other sports get like the baseball swing or the pitch.I think its time for this sport to get down to the nitty gritty and real facts.......by scientists. Not people claiming to know secrets of the game or mystics. Thanks for listening Jimjones
 
There is only one stroke.......the one you are currently having to use to make the shot that is before you.
 
There is only ONE stroke in pool. How that stroke is performed is many.
randyg
 
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