What I meant by a "normally accelerating stroke" is one that peaks at or just before contact with the CB - not one that continues accelerating past that. I believe that's what Bob had in mind with his smooth-topped velocity curve.
pj
chgo
IS THE GOAL TO NOT SLOW DOWN AT CONTACT
- Thread starter bbb
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pj
chgo
Great graph... I think it depicts exactly the ideal motion curve in relation to CB contact.
I butchered it to illustrate my point. Making a concerning effort to flatten out the velocity opens the door to flawed control. Can you do it..?..., sure. Anything to gain...?..., sure. Those gains worth running the risk of losing control over the other aspects of your stroke...?..., certainly not.
That's only very, very roughly what the stick velocity vs. time curve looks like. Measured curves are on Dr. Dave's website. My June 1999 column in Billiards Digest -- which is available on the sfbilliards.com website in case you don't have a collection of them -- and my March 2021 column both discuss the velocity/time curve and what they mean.
It's important to note that there is normally no flat portion to the top of the curve. I suppose it's possible but I've never seen it.
What I meant by smooth top is a smooth arc like a fly ball or the bottom of a swinging pendulum or the follow angle versus fullness of hit around a half ball hit. Because you are near a smooth maximum, anywhere close is good enough.
When I say smooth, I mean it is not an inverted V, but rather an invered U.
For what it's worth, here is something close to my usual stroke. This was described in my March BD article.
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The cue stick does not come to a halt on contact. It typically will lose half of it's speed in the 1-2 milliseconds of tip-ball contact and then be re-accelerated by the hand which is not slowed down by the tip-ball contact. See the diagram above.
Like I said, it was not an actual stroke graph. It was just a quick illustration to explain a point that wasn't explained very well with words.
Nope, never heard of anyone purposely trying to maintain a set velocity before striking the CB. The comments I've been making have were in response to the original question, as seen below:
My take on this is, yes it would be ok. However the effort and unlikelyhood of pulling off such a feat would not provide any real benefit, and more than likely introduce other cueing control errors.
wow.... we agree on something
I didn't see comments from anyone that tried constant speed. Along with all of my other testing I tried constant speed particularly on slow to slower medium speed shots. First, it is massively hard to do! Second, trying to hold that constant speed seems to introduce stroke flaws. I don't know if these would go away with more time trying the stroke but I decided it was great in theory, impractical in application. A machine could easily maintain a constant speed during the time of hit and would be unaffected by the problems I encountered but the human arm is a far more complex mechanism.
Looking at the pendulum stroke, I find that most top players using it hit the ball late, past ninety degrees to the floor and when the upper and lower arm form an acute angle, less than ninety degrees. Watch them addressing a cue ball. These conditions are easy to see at this point.
It seems that at the least their arm is past peak acceleration and acceleration has slowed. The arm appears to be starting to coast a little bit. Seems to disagree with the theory of what is good, too successful in practice to argue with!
Those curious about what I am saying can test easily enough on a table. Line up a shot, address the cue ball, then check lower arm position. Try hitting the shot with the arm vertical, ahead three or four inches, and behind three or four inches. Hitting early, three or four inches before the forearm reaches vertical, would seem to best suit the idea of hitting the cue ball at maximum acceleration but it sure feels odd!
Some of these things discussed on AZB are easy enough to test for ourselves if we have a table available. Theory and fact sometimes wander a long ways apart, other times are quickly proven to be the same.
Hu
Looking at the pendulum stroke, I find that most top players using it hit the ball late, past ninety degrees to the floor and when the upper and lower arm form an acute angle, less than ninety degrees. Watch them addressing a cue ball. These conditions are easy to see at this point.
It seems that at the least their arm is past peak acceleration and acceleration has slowed. The arm appears to be starting to coast a little bit. Seems to disagree with the theory of what is good, too successful in practice to argue with!
Those curious about what I am saying can test easily enough on a table. Line up a shot, address the cue ball, then check lower arm position. Try hitting the shot with the arm vertical, ahead three or four inches, and behind three or four inches. Hitting early, three or four inches before the forearm reaches vertical, would seem to best suit the idea of hitting the cue ball at maximum acceleration but it sure feels odd!
Some of these things discussed on AZB are easy enough to test for ourselves if we have a table available. Theory and fact sometimes wander a long ways apart, other times are quickly proven to be the same.
Hu
That agrees with my theory of what's good - hit the ball during the "smooth top" part of the stroke for maximum contact and speed accuracy. I think the arm's physiology does that pretty naturally at or just past the bottom of a pendulum stroke.
pj
chgo
Let’s compare pitching pennies to throwing a baseball
pitching pennies the arm goes back and forth more like a pendulum stroke
its reasonably smooth
and for me a sense of constant speed not a rate of acceleration
the baseball throw for distance is more slow as you bring your arm down and around but
as you get around your ear until release there is definitely an acceleration at least for me
it is possible to toss a baseball with the same feeling of constant speed like in the pitching pennies
if I need to move the cueball six diamonds or 16 diamonds I’m thinking speed of stroke like in pitching pennies and not rate of acceleration
jmho
I realized if you measured my speed of of the cue overtime
it probably changes so technically there is acceleration even though my inner feeling is not one of controlling acceleration
pitching pennies the arm goes back and forth more like a pendulum stroke
its reasonably smooth
and for me a sense of constant speed not a rate of acceleration
the baseball throw for distance is more slow as you bring your arm down and around but
as you get around your ear until release there is definitely an acceleration at least for me
it is possible to toss a baseball with the same feeling of constant speed like in the pitching pennies
if I need to move the cueball six diamonds or 16 diamonds I’m thinking speed of stroke like in pitching pennies and not rate of acceleration
jmho
I realized if you measured my speed of of the cue overtime
it probably changes so technically there is acceleration even though my inner feeling is not one of controlling acceleration
This is my take on the notion of constant speed. I never tried it, but just formed an opinion with a firm grasp on what it would take to make it happen. Thank you for adding your experience.
Couple of things. First the 'pendulum' is in relation to the cue not the floor. Not that you stated it, but the stroke isn't relative to gravity. Second, in practice the whole motion could be under acceleration, and only braking when the range of motion has ended. I don't doubt your thoughts on what you observed. Just dispelling the idea that once your forearm is on the 'upswing' that you must be decelerating.
Personally, I cue up to within an inch of the CB when I set my grip hand on the vertical (90 to the cue). Feathering the cue stops further away until I'm read to pull the trigger. Of course the ideal point to strike the CB is during that vertical position which I'm short of, and as you say I highly doubt most manage to pull it off. However this is yet another example of why flat cueing is advantageous. Flat cueists can travel that additional distance to the CB without deviating from the cue line.
As far as my rate of acceleration (if any) through the CB.... I can't say. Although I haven't tested as such. I'm fairly confident that I'm not slowing down, unless I'm purposely doing so.
Not being machines we accelerate, decelerate, change directions with or without a stop. The most critical part of a stroke may be the first inches of forward motion. A jerk to try to get to a fixed speed for as much of your stroke as possible is almost certainly going to introduce issues into your stroke. It would seem that a constant speed when hitting the cue ball would be best. It probably is best on paper. On the table the best we can hope for is to hit the cue ball in a narrow range of speed. If we constantly accelerate until impact the supporting muscles and tissues keep our stroke straight. If we transition from powering forward before hitting the cue ball things are more problematic. Acceleration from the transition is the simplest stroke and sometimes simple is best.
I don't disagree with a word you are saying except maybe what I bolded which is minor since it has no affect on performance. You can use muscle to accelerate through much more of the range of motion of your arm. However, the most popular theory seems to be let the cue do the work. This generally results in slowed acceleration, even sometimes slowed velocity of the stick before striking the cue ball.
There are various ways different people measure the bottom of the pendulum. Some use the floor or table which is flawed since we can raise or lower the stick considerably. Some, like you use the stick angle, a more accurate method. However, when using stick angle it means that most people are hitting the cue ball even later in their stroke than relating it t
o a level surface since the back of the stick is almost always slightly elevated. I try to write for all readers which can be kinda cumbersome sometimes. I consider the line from elbow to where you are gripping the cue to be perfect when it is at 90 degrees to the cue. Before that I consider to be an early hit and going past that point before hitting the cue ball I consider a late hit.
I did bold one part that I consider debatable. If our arms were fixed as the diagrams and such show, where you are hitting is more perfect as far as the tip moving flatly. Also we seem to have more propulsion in our arms without focusing on it when we hit slightly early compared to most people using the pendulum hitting later in their stroke. In short, I think your set-up and stroke are win/win if I understand correctly with zero drawbacks.
Do you have any video of your play? Not looking for ammunition for debate, I like looking at strokes that aren't run of the mill. I collected slipstrokes for years and still want any video of a slipstroke I can get. They too have some advantages but also require more effort to learn and maintain than most other strokes. I try to use the slipstroke now and then just because I don't think it should become a lost art. It also seems to be an advantage on a few shots.
Hu
Here you go:
I've posted a few videos on ABZ of either Dr.Dave challenges, ghost sets, or 14.1. I wouldn't say the fewing angle is the best to comment on stroke dynamics. I will also fore warn you that I do not completely adhere to my rigid mechnics when I'm feeling good, so don't be surprised if you notice some deviations.
thanks... ...and just so you know it's merely coincidence that I happened to post the 7-0 win...lolGood outs. Nice shooting.
Again, in terms of my fundamentals / PSR / stroke mechanics. I really don't make a concerned effort to follow them unless I'm grinding or trying to get in gear. However you do almost always see the traditional snooker stance, steady elbow, and my chin on the cue.
I did forget that that particular vid had the voice over though. It was motovated in response to some thinking that I'm relying on shot making and don't really pay attention to pattern play.
I'm always willing to listen to critiques of my game, so if any have anything they'd be willing to comment on I'm more than willing to read them here.