Timing

[Scott Lee]

I agree with you Mike. The cuestick is ALWAYS accelerating to the natural finish position. Why? Because it starts at zero (at the pause on the backswing), and accelerates through the end of the stroke. Even on a lag speed swing, you are still technically accelerating the cue (you just don't "feel" it). However, Rod's description of letting the weight of the cue and the timing create the speed of the stroke is also accurate. The 'throwing motion' is an accurate description for higher speed swings. Simply moving the cue across your bridge hand describes a slow swing. The finish is the important part.

Scott Lee
www.poolknowledge.com

 

[JoeW]

Hitting early

It seems to make sense that the cue ball should be hit early, before the center of the pendulum swing has been reached. From a biomechanics perspective the wrist and arm are lined up on the back swing and the initial down swing. At the center of the swing the wrist can flex and have more of a contribution to a sideways motion, thus making the stick move off line. Would it not be better to hit the cue ball when wrist and arm are naturally lined up than at the moment when the wrist can become more involved?

The body is concentrating on a straight line on the back and initial swing. The body must concentrate on controlling the wrist and a straight swing after the center of the pendulum has been reached.

I realize that these thoughts are contrary to many of the posts here and I bring up the idea as perhaps something that needs to be tested for the best control of one's swing / stroke.

One of the neater things about playing pool is that most of these ideas can be tested if one is creative in their approach.

When pitching a softball or throwing a bowling ball wrist action is primarily at the end of the swing -- is it not?

 

[Rod]

I think you gain control by giving up control. In other words if you try to control wrist movement you are steering the cue. That is the dreaded tension that sends the cue off line.

I think the wrist naturally returns to the same position as it was at address with no effort on your part. Let the free swinging weight of the cue take control. That allows the cue to go through in a straight line.

Rod

 

[ShootingArts]

another possible advantage of hitting early.

It seems to make sense that the cue ball should be hit early, before the center of the pendulum swing has been reached. From a biomechanics perspective the wrist and arm are lined up on the back swing and the initial down swing. At the center of the swing the wrist can flex and have more of a contribution to a sideways motion, thus making the stick move off line. Would it not be better to hit the cue ball when wrist and arm are naturally lined up than at the moment when the wrist can become more involved?

Joe,

One advantage of hitting the ball a little early is that the real tendency in most of us seems to be to hit the cue ball later than we think. There is a sweet spot to hit the ball in the pendulum stroke which is when the line from your bridge is tangent with the arc of your pendulum stroke. If you hit slightly early you are still in the early part of the sweet spot and following through into the sweet spot. If you normally hit a little late, then hitting still a little later than planned takes you completely out of the sweet spot where the vertical motion of the stick is minimal.

Since my observations indicate that hitting late is more common than hitting early I think that moving the typical contact timing of our shots slightly early from the perfect sweet spot makes sense. I am only talking back to a true 90? or an inch or two before it here, nothing radical. Of course this creates a very natural follow through too, another plus.

Hu

 

[CreeDo]

I'd think that hitting a bit early would rob the stroke of some speed/power and would tend to lead to undercooked english, particularly draw strokes. I don't know if it does much for left/right consistency, I'll try it tonight and see.

 

[ShootingArts]

speed power and draw

I'd think that hitting a bit early would rob the stroke of some speed/power and would tend to lead to undercooked english, particularly draw strokes. I don't know if it does much for left/right consistency, I'll try it tonight and see.

Extreme draw can benefit from a late hit as I mentioned earlier. Extreme follow can benefit from a closed bridge and an early hit.

Assuming that we are gradually accelerating until contact with the cue ball(I am not getting into after contact, theory and science are at odds) then the argument would favor an extremely late hit for maximum speed and power. Needless to say, we don't sacrifice control for that bit of extra power except sometimes when we get greedy on a break.

When we are only considering normal shots, the timing between where I am suggesting hitting and where many people hit now is maybe three to five inches. We can easily adjust to building speed more quickly or drawing back further on the backstroke if we choose to but more to the point, how often do we actually need the maximum speed and power we can put on a cue ball? Most of the time we need to place the tip properly and follow through for that vital few thousands of a second that the cue tip and ball are in contact. Rarely do we use maximum speed hits on the cue ball and when we do it is usually to try to overcome a poorly hit shot. We hit poorly when we try to hit harder than we can control our stroke. Do you see something coming full circle here?

Typing these things only helps clarify my thoughts. One thing I am sure of, most folks are like me, too happy with old habits to change most of them. I hate the idea of building new fundamentals. Hopefully once I actually start the process it won't be as painful as it is just thinking about starting from scratch.

Hu

 

[Jal]

What am I missing here? Isn't acceleration by definition the sensitivity (derivative) of the speed of the stick with respect to time?

Sorry for the delay but I had to re-familiarize myself with some old work.

My argument is that the cue's speed is a function of the entire force profile (over time), which I'm sure you'll agree with. As such, what's happening during the last few moments before impact (accelerating vs not vs decelerating) has very little effect, just as continuing to apply a force during impact produces, by itself, negligible gain.

If you model the force applied during the forward stroke as Asin(wt), I'm interpreting and error in timing to mean an unintended deviation in w, where w = 2pi/T, T = one full cycle period. The cue's speed sensitivity to deviations in w is less when impact occurs such that the phase angle wt is less than pi (ie, accelerating at impact), compared to wt=pi (zero acceleration at impact), which in turn is less than when wt>pi (decelerating during impact). Reducing w reduces wt, all else being equal. It also increases stroke length. These are the results spit out by a program, but I've just spent some time getting an analytical expression for it, as a double check.

Several other sources of error are also reduced when "accelerating through" as well. But speed sensitivity to variations in bridge length (given the exact same stroke) are greater when accelerating or decelerating at impact. The question is, when you set up with a different bridge length, are you aware of it and try to adjust stroke length accordingly? If so, then errors in this adjustment are less when "accelerating through". If not, speed errors are greater when accelerating.

The model Asin(wt), with a smattering of harmonics, is a pretty good representation of at least one stroke where we have accelerometer sampling. But even if this is typical of your average stroke, it's not been established that accelerating up to impact is tantamount to simply reducing w, ie, neatly stretching out the sine function.

I've done a lot of work on this but am trying to keep this short. Here is a graphical description of why stretching out (flattening) the sine function does what it does.

http://ww2.netnitco.net/users/gtech/StrokeSens.jpg

And here is why it should produce gains in cue speed if peak amplitude (A) is kept constant (theoretically):

http://ww2.netnitco.net/users/gtech/Fsins.jpg

I can get more draw, for instance, by moving my grip hand back, as Deadon mentioned earlier. Alternately, less peak force is needed to achieve the same speed.

I'm not pushing accelerating at impact, just offering up what I think are some benefits. A disadvantage is that energy is wasted...and then there's the bridge length thing.

Jim

 

[CreeDo]

I think you must be right hu -
I watched myself on a bunch of shots and I am definitely a late hitter, and I'm able to draw like crazy as needed. I dunno if my follow is affected, it seems like it's not as nice and natural for me.

Left/right I noticed no difference trying different bridges/butt grips. Possible having more stick between my hands (back hand further back, front hand further forward) feels a bit less wobbly side to side, which might be handy with my usual open bridge.

I think it's useful to know that draw might be a hair easier if you position your hands for a later hit.

 

[ShootingArts]

there you have it

There you have it, a hair easier. It isn't a lot of difference. It is kind of like using swoop on side english, it doesn't add much but sometimes just enough on a marginally possible shot. It is good to know that early and late timing have their places but they don't completely rewrite the books.

Hu

I think you must be right hu -
I watched myself on a bunch of shots and I am definitely a late hitter, and I'm able to draw like crazy as needed. I dunno if my follow is affected, it seems like it's not as nice and natural for me.

Left/right I noticed no difference trying different bridges/butt grips. Possible having more stick between my hands (back hand further back, front hand further forward) feels a bit less wobbly side to side, which might be handy with my usual open bridge.

I think it's useful to know that draw might be a hair easier if you position your hands for a later hit.