Physics behind a billiard shot

Factual Questions
81

Well, yeah. That certainly makes sense and is objectively true! Of course, you know, speed control is key…maybe unless you’re playing bubba at the local Whiskey Spotted Dick and feel compelled to start banging away, for some macho reason! Steal his girl or something!

I still don’t quite get it…you mean stroke hard or very hard and then pull back at the last second?

I’m working through Phil Capelle’s books on Play Your Best [Eight Ball] and PYB [Straight Pool], which are goldmines, for a B-player (at best…I don’t even know if I’d call myself a B player or shortstop yet…not enough regular table time in the past few years) like me right now. I don’t have a Fargo rating, and nor an APA rating, just an idea of what players (mostly APA are who I know in bars with 4x8 tables) are what, disregarding the notorious sandbagging possible.

Why would one accelerate into a shot for no reason? You can rely on forward roll, natural roll, &c. things that have principles of physics behind them. Think about straight pool (14.1) for example: in the novel TCoM, a great deal of commentary Tevis adds about Fast Eddie’s discomfort with letting his stroke out, given the differences between close, cluster play and even just the initial break in 9 or 8.

Yes, accelerate, but the right amount! I should hope we’re not just banging balls into pockets with extreme prejudice!

Well, when they’re breaking in 8-ball or 9-ball, sure as shit they accelerate! Like muthas! Personally I find most shots besides the break in those two games (no, I didn’t forget 10-ball, include that as well), fit the model of "imagine an egg between your foot and the gas pedal in a car! The right amount, but that IME is something anybody who plays for position/next ball/next three balls already does. Of course some shots need power, if you screw up and leave the table all messed up with having to go three rails to get position on the next, after contact with OB.

82

What I am talking about wouldn’t have as much to do with speed as it would acceleration right at impact. It might be a relatively soft shot but still accelerating upon impact. It is really just a form of follow through I guess.

83

I’m sorry if you thought I was being personal. I really wasn’t. I just didn’t understand what you were getting at. I think you were saying that there is a definite time and distance interval where the cue stays in contact with the ball, and that’s the place where some wrist action might be employed. Is that it?

If so, I’d just point out that world class players do not agree. I have never seen a top pro use wrist action in this way, and I played with one for years. I have watched many instructional videos on technique, and none have ever mentioned wrist action, other than to say it doesn’t work and to forget about it.

All of them say the same thing: The key to a good shot is a good stroke, and agood stroke is made by keeping a consistent stance, a level cue, and a straight back and forth stroke that does not wobble side to side. You will not find an instructional video or web site traching you how to use wrist action for spin, because wrist action in pool is not used for adding spin to the ball.

I just thought of one reason why amateurs might not be able to get good action on the cueball - they might be holding the cue too tightly. Once your forearm goes past the vertical on the downswing, if you have a rigid grip on the cue the cuetip will begin to rise because of the hand angle. Pros open their hands on the backswing to keep the cue level, and close it as they go through the vertical, which keeps the cue tip in the same spot throughout the stroke.

Have a look at Efren Reyes’ stroke in this video:

He opens his hand on the backstroke to keep the cue level, closes it as his forarm goes through the vertical, then opens it again to allow the cue to remain level. Notice that on the backstroke the cue was resting on this forefingers, and on the followthrough it’s resting on his back fingers.

Open your hand, curl the fingers as if holding a cue, and move it back and forth theough vertical. You can see what happens, and why you have to keep a loose grip. Amateurs that hold the cue in a death grip will hit the cueball higher than they think they are. That’s probably the real difference, plus fear of miscuing.

84

That perfectly demonstrated what I was looking for, “Perfect level” I never was overly concerned with wrist action, I know it came up during the thread., it also appeared to me to be accelerating right into the shot.

85

Beautiful video from The Magician himself.

Hard to say what, if any, conscious thought went into that stroke, on the part of Efren. If I had to guess, just on the basis of that one video (and keeping in mind I’m maybe a B- player at best), could be just subconsciously Efren trying to grab the cue solidly in order to set up for his next shot, although he can often be a very deliberate player who takes his time.

I think it’s fair to say without unduly tooting my own horn that the initial grip toward the butt end of the cue is what I’ve seen roughly 100% of decent players (I’ll be generous and say about my speed and above) use. That is, I’ve never seen anybody who can play ever use a rock-hard grip at the butt of the cue. Maybe some bangers at a bar playing “whatever” rules 8-ball, but nobody who regularly runs out or present any challenges.

That motion described in words by Sam_Stone about that shot might well be interpreted as a kind of “wrist action,” although it seems to me action by flexor tendons in the butt hand.

Back in the olden days, maybe it did seem like wrist action. Although I don’t know that knowledge of physiology has advanced all that much in the past fifty or sixty years, concerning the relevant tendons and muscles.

86

Overall I think “wrist action” is one of those idiomatic buzzphrases that gets incorporated into all sorts of sports commentary. Regardless of its applicability. Some guy’s greater at poker? “It’s all in the wrist action”. Har har. Same applis to tennis, pool, baseball batting, etc. Does the wrist have a role to play? Of course. Is there “wrist action”? Heck no.

Sam’s cited vid shows a guy who’s got far, far, more talent and skill than I ever had or ever will have. At my peak I would not last 1 rack against that guy.

Having said that I’m actually surprised at how much rise and fall he’s got in his cue motion. But what is key to me is that his set-up stroke and his impact stroke are identical except for more speed and a full follow-through instead of stopping short of impacting the cue ball. He aims and fires down the exact same path. As well, all his rise and fall happens early in the stroke. The last couple inches and the impact all happen with the cue traveling in an absolute straight line.

OTOH, lots of tyros do fairly consistent warm-up strokes, then their power stroke is utterly different. But it happens too fast for them to see/feel what they did wrong. Lather rinse repeat until they rise to their own level of incompetence, unable to get better.

87

Yes, I do think this does adequately demonstrate what we were looking for. The stick only has to travel in a perfectly straight line at the impact point and the follow through for that brief micro second. There is no true " Wrist action" But Efrin clearly uses his hand and wrist to maintain the position of the cue in relation to the spot on the ball he is striking.

88

This is a common stroke in Filipino players. Bustamante’s stroke is even more pronounced.

Some pros get away with terrible strokes that they make work for them. Keith McReady has a crazy sidearm stroke.

The thing with those pros is that they have practiced so many shots that the stroke is now in ‘system 1’ and they don’t even have to think about it. So long as they are consistently hitting the cueball in the roght place with the cue level, it works.