back-hand swoop and cue twist poll

[Patrick Johnson]

Colin:
after lots of playing using BHE I'm pretty convinced that pure squirt does increase with speed of shot

No offense, but I never take observations like this (based on "lots of playing") very seriously when it comes to figuring out what's happening at a mechanical level. You need controlled tests, particularly with subtle things like the interaction of squirt, swerve, stroke, tip/CB contact, speed, distance, butt elevation, table/ball conditions, etc., etc. Controlled tests have been done, and I think they all seem to say that speed doesn't significantly affect pure squirt.

But even if you're right that squirt increases with speed (or even if you're just talking about "effective squirt" including swerve), swooping is an inherently less-consistent and less-accurate way to adjust for that (compared with changing pivot length), even for those who are good at swooping. It's the equivalent of adjusting your aim with a rifle by swinging it in an arc while firing rather than simply changing your aim and firing while still. If there are any minor (and highly theoretical) advantages from that, they're way overpowered by the very real accuracy/consistency disadvantage.

pj
chgo

 

[SpiderWebComm]

Scott,

I don't see any harm in doing a study. It would be nice to know whether or not swoop can create any measurable benefit (e.g., more English). I will do my best with a "study," but I would like to find someone with a consistent and effective swoop stroke first.

BTW, I agree with you that the value of swooping is highly questionable.

Regards,
Dave

I'm still confused why a study is needed. Simply find a top Filipino who swoops occasionally and ask him why he does it. Not everything in pool is explainable in a physics lab. Unless you can find a machine with a brain, nerves and muscles, it's not apples/apples.

Dave

 

[Patrick Johnson]

Spidee:
I'm still confused why a study is needed. Simply find a top Filipino who swoops occasionally and ask him why he does it. Not everything in pool is explainable in a physics lab.

The player does it for reasons that may or may not be realistic - he may be getting a positive result for reasons he's unaware of. A good study would show differences between perception and reality.

pj
chgo

P.S. I beg to differ with the highlighted comment.

 

[Colin Colenso]

No offense, but I never take observations like this (based on "lots of playing") very seriously when it comes to figuring out what's happening at a mechanical level. You need controlled tests, particularly with subtle things like the interaction of squirt, swerve, stroke, tip/CB contact, speed, distance, butt elevation, table/ball conditions, etc., etc. Controlled tests have been done, and I think they all seem to say that speed doesn't significantly affect pure squirt.

None taken Patrick,
I agree it's not conclusive and would like to see more accurate tests done, such as the test Dr. Dave linked to earlier in this thread. Would like to see that extended into the 20+ mph range though.

But even if you're right that squirt increases with speed (or even if you're just talking about "effective squirt" including swerve), swooping is an inherently less-consistent and less-accurate way to adjust for that (compared with changing pivot length), even for those who are good at swooping. It's the equivalent of adjusting your aim with a rifle by swinging it in an arc while firing rather than simply changing your aim and firing while still. If there are any minor (and highly theoretical) advantages from that, they're way overpowered by the very real accuracy/consistency disadvantage.

pj
chgo

There are some occasional situations where it is not convenient to place the bridge at the required pivot point. Change in aim is one method, but its weakness is the the aim line and actual CB travel lines do not came out parallel. (Then again, swerve makes this true of a lot of shots also). Swooping on these occasions provides a compensatory method of sending the CB on a more parallel path to the aim line.

It's not a perfect solution, but in practice it does seem to make these shots more predictable than changing the aim line. A typical example is when the bridge is obstructed by a ball or a rail.

Colin

 

[Colin Colenso]

Colin,

FYI, I have some data on this in Diagram 2 of my February '08 article. We only tested up to 8 mph, but the squirt was relatively constant up to this speed. I also have a thorough analysis of squirt physics in TP A.31. I can't think of any physical effect that would create more squirt at higher speeds (based on the analysis), but I'm not saying it is impossible (just improbable). We will design and build a better machine in the fall and early spring. Hopefully, I can get more data then.

Regards,
Dave

That's great stuff Dave, I didn't know you'd done that robot squirt testing. I'd better spend some time familiarizing myself on all your work.

Regarding other physical effects that might change predictions of squirt behavior, I have proposed what I called Surface Property Induced Deflection at the time. This theory suggests that for wide offsets or at high speeds that there is a degree of slippage at the contact between tip and CB.

When we have elastic collisions there is a degree of grip and this varies. It seems reasonable to me that there can be a degree of elastic collision between the tip and CB. As I said, I'd expect this to take place more so with extreme offsets and at higher speeds.

That's why I'd like to see your testing move up into the 20 mph range and possibly some testing with larger tip offsets.

Colin

 

[Colin Colenso]

More thoughts on Swoop after some Testing

I spent a couple of hours testing some of the swoop ideas we've discussed here.

Some thoughts on:

More English / Spin
Not convinced at all about this. What I do think is that myself, like many others adopt a swoop, most noticeably on draw shots out of habit.

After years of habit the control becomes quite good. I find it quite hard to predict where I need to hit the CB to get the required draw when I need to select an aim point and cue straight at that point.

I suspect it would be better to learn the non-swoop method from the beginning for this shot.

Reduce CB Bounce
Inconclusive without more accurate and detailed testing. Though I'm beginning to think it is probably not worth all the effort to try to perfect for any small advantage it may offer.

BHE Shots when Bridge Length is Not Appropriate

There are definitely some shots here where I find swooping the most predictable compensatory method. There are alternatives though and for someone who finds controlling a swoop shot difficult, it would probably be best if they adapted and practiced the other compensatory methods. These could include change in pre-alignment, use of another cue, learning to play the shot with an uncomfortable or unstable bridge length.

Colin

 

[dr_dave]

Re: constant squirt vs. speed

FYI, I have some data on this in Diagram 2 of my February '08 article. We only tested up to 8 mph, but the squirt was relatively constant up to this speed. I also have a thorough analysis of squirt physics in TP A.31. I can't think of any physical effect that would create more squirt at higher speeds (based on the analysis), but I'm not saying it is impossible (just improbable). We will design and build a better machine in the fall and early spring. Hopefully, I can get more data then.

Your test was oriented to a limited specturm of 3-8mph.

I know for a fact that at slower than 3 mph speeds and with max tip offset on the equator, squirt is insignificant.

At slow speeds at a pool table (with slight cue elevation is required to clear the rails), swerve happens almost immediately, so it is difficult to separate out squirt and swerve. Our machine keeps the cue perfectly level, so there is no swerve (only squirt).

I am not equipped to study squirt at higher speeds but to suggest that squirt is constant from 8 to, say 20 mph is a leap of faith and IMHO should be tested.

Agreed. When our new machine is built later this year, this is the first experiment I will do.

Also, I think that your use of averages in the diagram 2 test of Squirt Part VII is problematic. The average of 1 and 100 is 50.5! (-:

This would be a problem is there was significant spread in the data, but there wasn't. The machine results were very repeatable.

Regards,
Dave

 

[dr_dave]

Filipino swoop "study"

I'm still confused why a study is needed. Simply find a top Filipino who swoops occasionally and ask him why he does it. Not everything in pool is explainable in a physics lab. Unless you can find a machine with a brain, nerves and muscles, it's not apples/apples.

I don't think I've asked any top Filipino players about swoop, but I have talked to several good players who swoop. Tom Ross and I have also discussed this at length. It seems that many players who swoop do so because they think it helps them apply more English. Some might think it helps them compensate for squirt. Some don't know what squirt is. Some can be very consistent and accurate with a swoop stroke. Some don't even know they swoop. It does seem to be a natural tendency for some players. But this is all anecdotal.

A "study" could help compare swoop and non-swoop strokes to identify if there are any clear benefits to learning one vs. the other (e.g., can a swoop stroke really create more English?). This might not be of interest to a top player who has swooped consistently and accurately for many years, but it might be of interest to an instructor or student who is not sure whether or not time should be spent on developing a consistent and accurate swoop stroke.

Regards,
Dave

 

[dr_dave]

results of testing

I spent a couple of hours testing some of the swoop ideas we've discussed here.

Some thoughts on:

More English / Spin
Not convinced at all about this. What I do think is that myself, like many others adopt a swoop, most noticeably on draw shots out of habit.

After years of habit the control becomes quite good. I find it quite hard to predict where I need to hit the CB to get the required draw when I need to select an aim point and cue straight at that point.

I suspect it would be better to learn the non-swoop method from the beginning for this shot.

Reduce CB Bounce
Inconclusive without more accurate and detailed testing. Though I'm beginning to think it is probably not worth all the effort to try to perfect for any small advantage it may offer.

BHE Shots when Bridge Length is Not Appropriate

There are definitely some shots here where I find swooping the most predictable compensatory method. There are alternatives though and for someone who finds controlling a swoop shot difficult, it would probably be best if they adapted and practiced the other compensatory methods. These could include change in pre-alignment, use of another cue, learning to play the shot with an uncomfortable or unstable bridge length.

Colin,

Thank you for sharing your thoughts. Obviously, I agree with your red conclusions.

Could you expand on your blue statement? If someone doesn't use BHE for aim compensation (e.g., let's say they aim and align their cue to adjust for squirt, swerve, and throw intuitively), why is bridge length important with a non-swoop stroke? It seems like changes in bridge length would make it difficult to be consistent with swooping. Right?

Thanks,
Dave

 

[dr_dave]

swoop justification not always clear

The player does it for reasons that may or may not be realistic - he may be getting a positive result for reasons he's unaware of. A good study would show differences between perception and reality.

Well stated. I agree.

I think many players who swoop do so to compensate for squirt, maybe even without knowing or caring if this is their reason. It might be better (i.e., more consistent and accurate) for most people (not including the people who already swoop masterfully) to learn other non-swoop methods to compensate their aim.

Regards,
Dave

 

[Russ Chewning]

I'm still confused why a study is needed. Simply find a top Filipino who swoops occasionally and ask him why he does it. Not everything in pool is explainable in a physics lab. Unless you can find a machine with a brain, nerves and muscles, it's not apples/apples.

Dave

:thumbup: :thumbup:

Russ

 

[Colin Colenso]

Colin,

Could you expand on your blue statement? If someone doesn't use BHE for aim compensation (e.g., let's say they aim and align their cue to adjust for squirt, swerve, and throw intuitively), why is bridge length important with a non-swoop stroke? It seems like changes in bridge length would make it difficult to be consistent with swooping. Right?

Thanks,
Dave

Dave,

Even players who don't use BHE for aim compensation are faced with the same difficulty when they have to take a longer or shorter than normal bridge length.

This is why so many intuitive english players find it very hard to deal with shots when they have longer or shorter bridge lengths. They'll tend to avoid using english on these shots unless the ball is a hanger.

Some of them will have learned intuitively to compensate with some swooping on some of these shots. Still, they are playing a bit of a guessing game, trial and error. They may find some methods help for short range shots and others for long range shots. The main problem is that as the distance between CB and OB changes, then they must aim to a different contact point.

In the diagram below, the two red lines indicate aiming lines using left english for shots of two distances. Notice that on closer shots the player doesn't have to aim very far from the contact point, but on longer shots the aim is significantly further away.

If a player is familiar with aiming adjustments using BHE and is familiar with the effect that swooping has on changing the effective pivot point, he has a quite predictable method of compensating for having non optimal bridge lengths when they occur.

For example, in the diagram, the player is forced to bridge at a length longer than the pivot point required for that shot. By swooping leftward during the stroke, he effectively increases the length of the pivot point. This is not as hard to estimate as you might imagine. A small swoop increases the pivot point a couple of inches, a large swoop by about 6 inches.

This allows a player to aim to the same contact point for different lengths of shot.

A better system might be to have a range of cues with different pivot points, but at the moment, I think swooping as a means to increase or decrease the pivot point (decrease by reverse swooping), is a more predictive compensation method than guessing the amount of aim compensation according to the distances.

Both methods can work, but I find the swoop method more predictable.

These are advanced shots, to be avoided when possible, but there are times when they are the only shot choice.

Hope that makes sense. I didn't have time to make a much clearer diagram.

Colin

 

[Patrick Johnson]

Even players who don't use BHE for aim compensation are faced with the same difficulty when they have to take a longer or shorter than normal bridge length.

Sensitivity to bridge length is the main problem with BHE (and, to a lesser degree, with "hybrid" BHE/FHE). Not using BHE avoids this sensitivity to bridge length, by definition.

With Front Hand English (pivoting at the back/grip hand and moving the front/bridge hand) the angle of the cue is determined by the position of the back/grip hand, so the front hand is in line with the adjusted aim no matter where the bridge is.

The same is true for adjusting "by feel" - aim is adjusted by simply estimating the required angle and aligning the entire cue with it. Since the entire cue is aligned with the shot it doesn't matter where either hand is placed on it - the bridge can be as long or short as needed.

I think swooping as a means to increase or decrease the pivot point (decrease by reverse swooping), is a more predictive compensation method than guessing the amount of aim compensation according to the distances.

There's always some "guessing" involved, no matter how you compensate for squirt/swerve. Because virtually all shots have an element of swerve, "mechanical" methods of compensating for squirt (BHE/FHE/hybrid) will always be off to some degree without some additional adjustment "by feel". I think of these mechanical methods as "approximating" techniques (like aiming systems or banking/kicking systems) that make most of the adjustment for you and leave you less to estimate. And I think swooping is a way of replacing that inevitable final estimate with another "semi-mechanical" adjustment that incorporates "feel" into its execution.

Of all the methods of squirt/swerve compensation, I think estimating from experience ("guessing") is the most accurate and reliable, assuming you have a facility for it. By substituting for most of the estimation required, mechanical methods obscure the relative effects of squirt and swerve, making it that much more difficult to learn the additional adjustments that are always necessary.

pj
chgo

 

[SpiderWebComm]

Well stated. I agree.

I think many players who swoop do so to compensate for squirt, maybe even without knowing or caring if this is their reason. It might be better (i.e., more consistent and accurate) for most people (not including the people who already swoop masterfully) to learn other non-swoop methods to compensate their aim.

Regards,
Dave

I think there are reasons not being discussed - and I'm not sold on the fact it's as unpredictable as everyone is saying. I'm also not convinced 100% they don't know or care what they're doing. OF COURSE they know they swoop vs. stroking straight! I think there's a preconceived notion that these elite players fell off the pumpkin truck at the county fair and they're idiot savants or something.

Swooping involves an entire different set of muscles as opposed to stroking straight - many of which are larger muscles with less "twitch" movement. We think it's crazy and implausible because of the dynamic nature of the movement, but my mind is open and I don't believe for a second they don't have a clue as to the why's and how's and that it's 100% subconscious. The action might be subconscious... but the reasoning behind it isn't.

 

[SpiderWebComm]

Of all the methods of squirt/swerve compensation, I think estimating from experience ("guessing") is the most accurate and reliable, assuming you have a facility for it. By substituting for most of the estimation required, mechanical methods obscure the relative effects of squirt and swerve, making it that much more difficult to learn the additional adjustments that are always necessary.

pj
chgo

I promise I'm not gonna rehash our old argument on this. I just hope someday you come out to DCC and you and I can share notes sometime privately. I'd like to setup complete random medium to hard difficulty inside-english shots with you. You can have a 15 second shot clock and I'll just get down, pivot, and fire with no feel adjustment. I know you play well, but I'd hypothesize I'd keep up with your percentage with a quick mechanical pivot. I just don't think you're up to speed with all of the pivot techniques.

Bridge length, swerve, pivot points, .....etc.... doesn't matter for the most part. The lab might tell you it does with a robotic arm, but in real life it doesn't. I aim the exact same way (and I mean THE SAME) for just about everything. I think the only variable is follow-through, which changes depending on distance.

It'll be fun, like a democrat and republican going at it. I'll open myself up... I've eaten lotsa crow in the past, so I'll man-up on here if I'm hot airing it.

 

[Patrick Johnson]

I promise I'm not gonna rehash our old argument on this.

I forget the details of that, but I'm glad not to do it again.

I just hope someday you come out to DCC and you and I can share notes sometime privately.

I'm pretty sure I'd enjoy that. You seem like a good guy (even when I'm pissing you off) with real love for the game.

I'd like to setup complete random medium to hard difficulty inside-english shots with you. You can have a 15 second shot clock and I'll just get down, pivot, and fire with no feel adjustment. I know you play well, but I'd hypothesize I'd keep up with your percentage with a quick mechanical pivot.

I wouldn't be surprised if you did better than me - I'm not a great player, just a student. But you're barking up the wrong tree if you think that will convince me yours is an objectively better way. I just think it's more suited to you - that's why I said mine is better "assuming you have a facility for it".

I just don't think you're up to speed with all of the pivot techniques.

I'm sure that's true, but I'm also pretty sure it doesn't matter.

Bridge length, swerve, pivot points, .....etc.... doesn't matter for the most part. The lab might tell you it does with a robotic arm, but in real life it doesn't.

It might not matter to you, but I assure you it matters at the level of mechanics. You're saying you don't have to think about those things because your technique takes care of them for you. I'm saying they come into play regardless, and I don't think your technique takes care of them in the most "universally" beneficial way - just the way that works best for you. For instance, I'm willing to bet that your technique works over a more narrow range of shots than mine does. On the other hand, your technique may be easier/quicker to learn and allow you to focus more on other aspects of the shot.

I aim the exact same way (and I mean THE SAME) for just about everything. I think the only variable is follow-through, which changes depending on distance.

That statement means to me that you may not be fully aware of the subtle differences in the way you're aiming or executing your shots. That's not a criticism of your choice of techniques: it may be the best one for you.

It'll be fun, like a democrat and republican going at it. I'll open myself up... I've eaten lotsa crow in the past, so I'll man-up on here if I'm hot airing it.

No manning-up necessary - it'd be fun just for the sake of it. I'm not trying to say mine is the "universally" best way, just like I don't say my way of aiming (without formal systems) is universally best. I'm just trying to separate objective fact from perception so those with choices to make know more about why they might choose to pursue one way over another.

pj
chgo

 

[Colin Colenso]

By substituting for most of the estimation required, mechanical methods obscure the relative effects of squirt and swerve, making it that much more difficult to learn the additional adjustments that are always necessary.

pj
chgo

Patrick,

I've been playing by feel since I grew up with a snooker table from age 7 until a couple of years ago when I started to study and practice BHE.

Using BHE has done wonders for my being able to isolate, better understand and more consistently compensate for squirt and swerve.

When all aspects are mixed into one combined feel of a shot, it is very hard to know which part of the equation was guessed incorrectly.

I am a much more adept player these days when it comes to using english thanks to adopting BHE as an aiming and compensation method, and the more I use it and study it, such that I mechanize and fine tune the adjustments on a wider range of shots, I'm sure that aspect of my game will grow increasingly stronger.

This is anecdotal yes, but nearly everyone I know who has spent enough time to familiarize themselves with the basics of BHE has been astounded at the way it has helped them with certain shots.

However, using BHE for a wide range of shots requires deeper knowledge and the formation of predictable systems of adjustment. Once those are learned, feel (in terms of aiming), other than the feel to line up a rolling plain ball pot, becomes largely unnecessary.

I think the main reason we don't see more players using this method is because there has never been a comprehensive guide written to describe the various adjustments. That is a project I'm currently working on.

The BHE shot that most people learn is only useful for a narrow range of angles and at certain speeds. The IE 20+ degree cut and gearing OE (basically). But it can be used for all shots if the appropriate adjustments are made.

Yes, the system is complex, but I think it is far less complex that the task of trying to learn aiming by feel for every type of degree of english, pace of shot, length of bridge and angle of cut.

And this doesn't even consider the troubles that aiming differently for every type shot has on imprinting angle memory. If we aim the same for every shot of different angle, regardless of the spin required, or the distance of the shot, that line, for each angle, gets burned into memory. The bridge just begins to fall straight into the correct position for the pot angle. Once the bridge is set, it is simply a matter of making the mechanical adjustment.

So this system would require recognition of about 10 lines (for 10 angles) on each side of the center of the OB to give accurate results. Conversely, aim by feel requires the memorization of hundreds of aim points for the various types of pots. That is why it takes years of hard practice to be able to develop a feel for all those aiming points.

Colin

 

[dr_dave]

Sensitivity to bridge length is the main problem with BHE (and, to a lesser degree, with "hybrid" BHE/FHE). Not using BHE avoids this sensitivity to bridge length, by definition.

With Front Hand English (pivoting at the back/grip hand and moving the front/bridge hand) the angle of the cue is determined by the position of the back/grip hand, so the front hand is in line with the adjusted aim no matter where the bridge is.

The same is true for adjusting "by feel" - aim is adjusted by simply estimating the required angle and aligning the entire cue with it. Since the entire cue is aligned with the shot it doesn't matter where either hand is placed on it - the bridge can be as long or short as needed.

There's always some "guessing" involved, no matter how you compensate for squirt/swerve. Because virtually all shots have an element of swerve, "mechanical" methods of compensating for squirt (BHE/FHE/hybrid) will always be off to some degree without some additional adjustment "by feel". I think of these mechanical methods as "approximating" techniques (like aiming systems or banking/kicking systems) that make most of the adjustment for you and leave you less to estimate. And I think swooping is a way of replacing that inevitable final estimate with another "semi-mechanical" adjustment that incorporates "feel" into its execution.

Of all the methods of squirt/swerve compensation, I think estimating from experience ("guessing") is the most accurate and reliable, assuming you have a facility for it. By substituting for most of the estimation required, mechanical methods obscure the relative effects of squirt and swerve, making it that much more difficult to learn the additional adjustments that are always necessary.

Excellent post! Good point about swoop incorporating the "feel" adjustment into the execution phase of the stroke. I think most people would do better to do the "feel" adjustment before stroke execution, and use a more accurate and consistent straight stroke. Also, changing bridge length would make the swoop "feel" even tougher to master.

Regards,
Dave

 

[SpiderWebComm]

Excellent post! Good point about swoop incorporating the "feel" adjustment into the execution phase of the stroke. I think most people would do better to do the "feel" adjustment before stroke execution, and use a more accurate and consistent straight stroke. Also, changing bridge length would make the swoop "feel" even tougher to master.

Regards,
Dave

That's assuming the feel adjustment is part of the execution phase, AND if there even IS a feel adjustment. This is a fascinating thread, but I think you guys are assuming a lot of stuff you don't know because neither of you are elite players or swoopers. It's speculation. I'm not saying I don't agree with you. I'm just trying to keep this balanced for the other readers so they don't read this stuff as gospel--- because none of it is. I dont see the top filipinos messing with bridge length either. Not EVER, just saying not OFTEN at all.

 

[Colin Colenso]

Just one more thought I wanted to add regarding the controllability of using swoop as an adjustment method when forced to use a longer or shorter bridge for BHE, versus the traditional feel method.

Yes, Patrick is right that swooping with an extended bridge is a little tougher than with a normal length bridge, but for me, and most with a little practice, I don't think it is hard to execute.

On the other hand, if aiming by the traditional feel method, then the aim line will change according to the degree of side english being applied. If you strike a little off the aim, then the direction will be off.

If using swoop to change the pivot point, the degree of english will hardly affect the line of the CB.

And remember, I am only talking about using swoop when the approriate pivot point bridge length is not available to me, which may be less than 1 in 10 shots where I'm applying english. And I might use english only 1 shot in 3. (Note: It actually happens mostly when the CB is near to a rail and I cannot use a long enough bridge comfortably)

So for about 97% of shots, I am all for piston like stroking.

Colin