Dwell Time .....

BB said:

Basically Freitas is trying to minimize the deceleration force.

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I think BB is barking up the right tree in part. Increasing the amount of time you can hold the ball is about slowing it all down at impact... then shooting it out. That requires a soft touch... with acceleration. This is what Carl is talking about serving with great spin. This concept also applies to counter-looping incoming heavy topspin with a soft grip and great acceleration. This gives max spin without max impact transferred to the ball. You also get great ease of controlling that incoming topspin. FX-P and Karis are two great rubbers at doing this against an incoming loop.

One can transfer the maximum possible amount of force to the ball be firming up strong right at impact. You get great penetration to sponge, great wrap on ball of topsheet, great rebound force from blade/sponge/topsheet… resulting in hyper spin and speed depending on how solid, tangential, or solid/off center you impacted the ball. This is the argument Lightzy is making. The spin and speed are there from the firming up at impact, but it doesn't make the dwell longer... but it sure as heck delivers a mountain of pop to the ball and makes the ball move out with pace and spin. This is how 90 lb kids bang the ball so hard. Once they are able to whip it more, they get even more spin (more power) to go with that pace.

This last impact above, there is also use of dwell. It is still catching and throwing, but at a higher impact force and bat speed.

This whole discussion about how dwell works and how to transfer power to the ball is great stuff... we ought to get Michael Maze to chime in during his upcoming interview.

Dan... ask MM personally how he gets more dwell and how he transfers power to the ball. We all love to hear his view and respect his opinion.

Suga D said:

This here.
+1.
Thanks Carl.
[Emoji106]
Some wood types seem to be able to increase the time the ball sits or rather dwells on the racket more than other wood types.

When i changed from my stiff Waldner Dotec Carbon to an old flexy Nittaku 3+2 Hinoki Carbon blade but using the same rubber setup (to that time it was Spinart on the fh and t05 on the bh) the dwell time felt notably longer which made it much easier to impart rotation to the ball even when in reality it just was the fraction of a second.
But not only that, the trajectory, the flight curve, was higher and more bent.

This feeling was only topped by an old Nittaku 3ply allwood Hinoki blade that provided an even more extended dwell and allowed me to compensate a bit of the loss of rotation due to the 40+ p-ball.
Also the carbon must have shortened the dwell compared to the 3ply allwood. Once more the trajectory (the throw angle) was higher plus the carbon has numbed down the lovely feeling that the Hinoki provides. On the allwood Hinoki i could feel much better when i hit the ball in the zone (the sweet spot) and when i hit it rather edgy.
Now with that 3ply All wood Hinoki i slowly started feeling that what old experts call the Hinoki stickyness. It almost felt like catching the ball and throwing it back. The post after my first session with that blade must still be somewhere in the depths of this forum.

Just lately i received 3 handcrafted customized Hinoki allwood blades.
The 3ply has the strongest flex and feelingwise the longest dwell of them.
The 5ply feels better when taking a step away from the table. Powerlooping by hitting more through the sponge just feels a little easier than with the 3ply.
The 7ply is the stiffest and at first felt a little awkward after being used to a flexy 3ply. It seems to provide more speed when looping from the back and even from 2 steps behind felt powerful and dangerous.
Compared to the Dotec even not so thinly brushed loops were spinnier and kicking off stronger after bouncing with the 7ply Hinoki.
One can tell i really love these blades even though the old Hinoki blades feel a bit more direct.

Hard to believe that the feeling of the handcrafted blades will even get better when more of the wood's natural moisture has evaporated over the years.

And even though Hinoki is often mentioned to be the spinners ambrosia, i've once met a guy with single ply Hinoki and he could brushloop quite strongly but also powerloop and flat hit some balls like i've never seen before.
One day i'll definitely try out a single ply Hinoki too....

[Emoji2]

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Awesome post all the way through.

The Darker Speed 90 (10mm 1 ply Hinoki) that I have tried is, by far, without question, the MOST AMAZING blade I have ever hit with. Nothing even comes close.

I do think it wold be hard for a shakehand player to use a blade that was 10mm thick, at least for serving. But that blade did everything better than anything else I have ever felt.

If one ply Hinoki blades did not break really easily and were not crazy expensive, I would use one. Nothing compares. Nothing.

Lightzy said:

There is more sponge to compress at a 45 angle impact than there would be straight on, before hitting the blade and bringing the ball to a rapid stop. And storing some energy in the ball itself also through compression.

Relative speed is an important component of dwell (penetration) but angle (the volume of topsheet/sponge in the way of the ball) is also very important, and a fair few factors besides.

Also when we talk about dwell time, as tt players, we're thinking of it in terms of spin that can be imparted on the ball on its way out of the racket. Not about actual time, and never the penetration of the ball head on, which will only impact speed, and then possibly negatively so.
That's also why the compression of the ball can also be discounted, as it cannot really add to spin. Which is what i was agreeing to disagree about with hipnotic earlier.

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Ok, i have to chime in again. You seem o confuse a lot of stuff, i never talked about ball deformation. Also, saying something doesn't matter just because you think it doesn't metter doesn't make it true.

In a shot, the ball comes in contact with the rubber, the rubber and sponge compress, the ball compresses, the blade bends AND deflects, the blades comes to the original position, the rubber springs back and transfers the energy to the ball. All of these affect dwell time. It's in the name "dwell time", the time that the ball stays on the racket. As long as it is bigger than zero it exists and can be accounted for.

And just to answer brokenball. For me dwell time means more control, not so much because of the "time" aspect, but because i have more feedback. And i think this is Lightzy point, all we care as players is the feedback, but that doesn't mean we cant try to understand what is really happening. However, dwell time is not always desirable, sometimes you just want the ball to fly out of the racket as fast as possible. I have a teammate that puts heavy sidespin on the bh loop, it's very hard for me to direct the ball where i want because i feel i have too much dwell time, the ball just sinks in and flies straight out.

BB is the only one who directly said longer dwell is a function of decelerating the ball.

This is done with a light touch and even a decreasing light grip changing to light as ball impacts bat and you accelerate.

The catch and throw feel is finding a way to decelerate the ball (decreasingly light grip before and at impact) and accelerate (throw the ball).

You can do this with a variety of grip pressures. The lighter the grip, the longer it can stay on.

Still, you do not need a super long dwell time to spin the ball.

A tangential strike vs an incoming topspin ball that is accelerating and has a grip firming up right at impact will send back ridiculous spin and speed... and that situation has less dwell than the light grip.

Donic Appelgren or Xiom Allround S, with a (medium-)hard rubber 47degr+ will give you control and lots of dwell time.

Der_Echte said:

BB is the only one who directly said longer dwell is a function of decelerating the ball.

This is done with a light touch and even a decreasing light grip changing to light as ball impacts bat and you accelerate.

The catch and throw feel is finding a way to decelerate the ball (decreasingly light grip before and at impact) and accelerate (throw the ball).

You can do this with a variety of grip pressures. The lighter the grip, the longer it can stay on.

Still, you do not need a super long dwell time to spin the ball.

A tangential strike vs an incoming topspin ball that is accelerating and has a grip firming up right at impact will send back ridiculous spin and speed... and that situation has less dwell than the light grip.

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More non-sense. Has anybody done the calculations? I have.
What if the ball is traveling 1 m/s 5m/s or 10 m/s at impact?
What are the ranges of expected impact forces for impacts at the speed above?
What are the necessary conditions to 'catch' the ball?
What are the necessary conditions for dwell time to be extended?
Until someone answers these questions there will be posts about dwell time over and over and over and over and over......again.
Baal is the only one that has come close and that was years ago on mytt.

brokenball said:

More non-sense. Has anybody done the calculations? I have.
What if the ball is traveling 1 m/s 5m/s or 10 m/s at impact?
What are the ranges of expected impact forces for impacts at the speed above?
What are the necessary conditions to 'catch' the ball?
What are the necessary conditions for dwell time to be extended?
Until someone answers these questions there will be posts about dwell time over and over and over and over and over......again.
Baal is the only one that has come close and that was years ago on mytt.

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Good times

This:


I wonder if frankie knew what he was getting the whole forum into by necromancing this old dead thread back to life?

There is something nobody talk here... that's the human reaction time.
The average human reaction time is 0.25 seconds to a visual stimulus, 0.17 to an auditory stimulus, and 0.15 seconds to a tactile stimulus.
So just explain me how you adapt your position / angle at the same moment you're hitting the ball when the contact ball/rubber is not longer than few milliseconds? the ball is out before you make any action / reaction, that's why table tennis is a sport of reflex, anticipation and training
The feeling, the touch, you have it or not and this is what really makes the difference between the top players and the rest of humans as it is natural. Obviously you can increase it a bit with training, but if you're not naturally skilled you will never reach the top. We all know a player who's training 4 or 5 hours per week since years and still a potato playing tt. On the other side we all know one who reached the top in a few years.

This is why for me "dwell time" is a myth, not because it doesn't exist but because you can't do nothing with it.
On the other hand the example of serve could not be an example of "dwell time" as what we are doing is not a standard phase of play but just the engagement ( the ball has to touch both side of the table when only the opposite when playing), and you can have a longer or shorter contact depending on the velocity of your bat when you hit the ball from speed to slow and slightly negative.

Yes.

Actually on the MyTT thread that brokenball mentioned, that was my main point. The conduction velocity of action potentials means that the ball has shot off your blade before a sensory signal even reaches your spinal cord.

But I definitely don't want to revisit all that!!!

One thing I would add is that blades have a timbre, like a musical instrument. When the ball strikes the blade it vibrates for awhile, and it could be that the duration of those vibrations can be felt and contributes to whatever it is that people are sensing that they think might be dwell. I'm just guessing about this last part though. It may even be that whatever it is about the blade that determines the "timbre" of the blade also has some effect on how it plays. Again, just a guess. I'm no engineer!

I'm not guessing about the biophysics of nerve conduction, though.

I'd like to point out, just because you feel the contact after the dwell time had already passed, doesn't mean you don't feel the difference between a shorter and longer contact. Just means you feel it after the fact.

Equally, just because you can't change your stroke while you feel the contact, doesn't mean you can't do things beforehand to create a longer contact.

It does, however, mean that adjusting your stroke 'during' contact is pretty much bs. What is likely happening is that you are preparing your stroke to better create longer contact, and the 'feel' just serves as feedback to how well you did the preparation, so that you can refine your preparation for the next time you do it.

Gwenved said:

There is something nobody talk here... that's the human reaction time.
...

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Dwell time has nothing to do with human reaction time. It is the time the ball is in contact with the rubber.
There is a thread on mytt started by Anton call "obscure question". It goes on and on because people couldn't separate dwell time, contact time, from , "touchy feelly" time.

This is why for me "dwell time" is a myth, not because it doesn't exist but because you can't do nothing with it.

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Dwell time isn't a myth. The ball is in contact with the rubber for a very short time normally.
You are right that you can't do much with it. It amazes me that people seem to be so concerned about dwell time but are unwilling to really understand it.

To Baal's credit. He is the only one that has even attempted to estimate the dwell time. There are PhDs in physics on these forums, I know there are on mytt, and they hide.

brokenball said:

Dwell time has nothing to do with human reaction time. It is the time the ball is in contact with the rubber.
There is a thread on mytt started by Anton call "obscure question". It goes on and on because people couldn't separate dwell time, contact time, from , "touchy feelly" time.


Dwell time isn't a myth. The ball is in contact with the rubber for a very short time normally.
You are right that you can't do much with it. It amazes me that people seem to be so concerned about dwell time but are unwilling to really understand it.

To Baal's credit. He is the only one that has even attempted to estimate the dwell time. There are PhDs in physics on these forums, I know there are on mytt, and they hide.

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Hi Brokenball,
Please read better my post ( or maybe I didn't explain well my thoughts), what I'm saying is as our reaction time is longer ( between 10 and 100 time) than the contact ball / raquet we cannot adjust our stroke during the contact / dwell time. Simple like that, and it is to respond to all those who said that a longer dwell time allows you to adjust your stroke. Nothing more.
I don't need sentences as "there Phd in physics", I've learned physics too even if I'm not Phd. No need to be Phd to expalin the contact ball/raquet.
Thanks

I love how the OP is active but has never replied.

But thanks to frankie, I've stumbled upon some interesting studies with results that are consistent with my own observations.

Gwenved said:

Hi Brokenball,
Please read better my post ( or maybe I didn't explain well my thoughts), what I'm saying is as our reaction time is longer ( between 10 and 100 time) than the contact ball / raquet we cannot adjust our stroke during the contact / dwell time. Simple like that, and it is to respond to all those who said that a longer dwell time allows you to adjust your stroke. Nothing more.
I don't need sentences as "there Phd in physics", I've learned physics too even if I'm not Phd. No need to be Phd to expalin the contact ball/raquet.
Thanks

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While I agree with you that longer dwell time, doesn't allow you to adjust your shot by feel, because the contact time is never long enough for you to do it with that kind of signal latency.

I disagree with the rest of what you said. 1) Dwell time exists, and is both a property of the bat/ball and the nature of the stroke. 2) Even though you can't adapt your bat/swing during during the stroke by swing, that's probably not where all of the adaptation is happening anyway.

1) Dwell time as people use it, for a normal rally shot. Is largely increased by reducing the perpendicular force of the contact between the bat and the ball. This can be done, firstly by just playing a slower shot, but also by playing a more tangential/closed blade angle shot (as it reduces the perpendicular component of the force). That is to say all other things being equal, a slower shot has a longer dwell time, and a brushier/spinnier contact also has longer dwell time. While having a longer dwell time, is probably not something worthwhile of a goal for training, it tends to be an indicator of a spinnier ball (or just a slower shot). Obviously, the elastic properties of your bat/rubbers will also create longer or shorter dwell times, which you may only feel after the point of contact, but you feel nonetheless.

2) You can adjust your stroke 'during' the contact (though i'm not sure if this is actually usually the case in practice), but you are just not doing it by feel of the contact. This is actually exactly the same control systems problem as when you are level matching with a very slow sampling rate.

Because the system is receiving information too infrequently, you can't depend an accurate reading on it's window of action, instead you need to use the information over a period of time before your window to act, to predict/extrapolate the position/speed of your target at that window of time need to act on it(what TT players are doing is probably some version of visual servoing). That is to say, at the actual point of contact, you are acting on predicted information and not the actual tactile feedback your hand is giving you, and you are performing somewhat preplanned actions.

What training 'feel' probably is in reality, is getting better at the ability to both accurately predict before actual contact the speed/position of the ball at point of contact and 'dialing in' and whatever you need do during your stroke including anything, if anything, you need to do during the point of contact with that prediction.

Hysteresis said:

While I agree with you that longer dwell time, doesn't allow you to adjust your shot by feel, because the contact time is never long enough for you to do it with that kind of signal latency.

I disagree with the rest of what you said. 1) Dwell time exists, and is both a property of the bat/ball and the nature of the stroke. 2) Even though you can't adapt your bat/swing during during the stroke by swing, that's probably not where all of the adaptation is happening anyway.

1) Dwell time as people use it, for a normal rally shot. Is largely increased by reducing the perpendicular force of the contact between the bat and the ball. This can be done, firstly by just playing a slower shot, but also by playing a more tangential/closed blade angle shot (as it reduces the perpendicular component of the force). That is to say all other things being equal, a slower shot has a longer dwell time, and a brushier/spinnier contact also has longer dwell time. While having a longer dwell time, is probably not something worthwhile of a goal for training, it tends to be an indicator of a spinnier ball (or just a slower shot). Obviously, the elastic properties of your bat/rubbers will also create longer or shorter dwell times, which you may only feel after the point of contact, but you feel nonetheless.

2) You can adjust your stroke 'during' the contact (though i'm not sure if this is actually usually the case in practice), but you are just not doing it by feel of the contact. This is actually exactly the same control systems problem as when you are level matching with a very slow sampling rate.

Because the system is receiving information too infrequently, you can't depend an accurate reading on it's window of action, instead you need to use the information over a period of time before your window to act, to predict/extrapolate the position/speed of your target at that window of time need to act on it(what TT players are doing is probably some version of visual servoing). That is to say, at the actual point of contact, you are acting on predicted information and not the actual tactile feedback your hand is giving you, and you are performing somewhat preplanned actions.

What training 'feel' probably is in reality, is getting better at the ability to both accurately predict before actual contact the speed/position of the ball at point of contact and 'dialing in' and whatever you need do during your stroke including anything, if anything, you need to do during the point of contact with that prediction.

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Hi Hysteresis, I've never said( or wrote) the dwell time doesn't exist. I just say it is a myth as you describe it because the rate reaction time/ dwell time is between 1/10 and 1/100.
1/ Even if you play a slower shot you depend on the velocity the ball arrives. Even like that the contact is really short, shorter than your reactivity so no way to adjust your shot during the contact time...
2/ if you were able to adjust your shot during the contact time as example you'll never fail a block or never fail when pushing the ball. Are you able to do it?
3/ this is exactely why training allows you to predict and chose the accurate stroke before the ball arrives when your reaction time is not the problem to solve the situation.
Regards.

Anticipation,

Formula one drivers have better than average reactions, and they also ‘read the Road’ sort of memorise all the bumps and way the car will handle at a certain point on the track, then they anticipate and react before the event.

They still won’t be able to ‘react’ that much faster to an unanticipated event though.

I also remember watching a science programme many years ago, which was about “looking at the ball, watching the ball onto the bat or racket”

All these England and international cricket stars, tennis players etc all said they watch the ball all the time. When asked if they shut their eyes? Everyone one of them said ‘No way, I watch the ball like a hawk’ or similar.
They were then filmed with an ultra high speed camera. Everyone of them had their eyes closed at impact!!!
They were totally astonished!!! Gobsmacked!!!

The scientists then explained that because your brain knows there’s a period of time (milliseconds) that it’s impossible for you to react (for your brain to receive info, process and send the required signal to your muscles and for the muscles to react) there’s actually no point in using your sight during this extremely short period of time!!! So you unconsciously blink. It’s so fast you don’t even know you’re doing it !!!

They then put bumps in the practice cricket wicket.
Calculations were made for ball speed, and distance the ball would travel in the time the brain / body cannot react within, (let’s call this ‘reaction distance’) The bumps were then placed inside this ‘reaction distance’. Which in effect meant they would be unplayable.
Bowling robot then fired balls at the batsmen, not one ball that hit a bump and was deflected from its ‘normal’ flight path was successfully hit, a ball that missed a bump and therefore continued in the normal way was played successfully by the batsman!!!

To say ‘that they didn’t watch the ball’ was a bit much!!! It’s very very short amounts of time, the camera just picked up a blink, something that happens all the time during the day and you never realise it !!! (well your brain chooses to ignore it!!) It’s ‘natural’.

So I suppose dwell time exists, but it’s still different and varies for a range of shots played with the same blade / rubber.
If a shot is played with the same force, speed , bat angle, all the variables replicated exactly, then the ‘dwell’ should be the same each time as well.

You may ‘feel’ the minuscule difference of a shot (after the fact).

You cannot ‘react’ at the very moment of impact.

players can anticipate and replicate what they have ‘felt’ and how they played a shot to get that feeling previously.

Just to be clear, you would not be 'reacting' during contact, you simply continue to make calibrations as you continuously receive sensory information.

That is to say, when you make adjustments to bat angle or whatever during the contact time, you are not doing that in response to the feel of the contact, you are just doing minor calibrations to your stroke as you continue to receive (usually visual) information on where the ball is, what direction it's going and how fast it's going from before the point of contact. Even after you've already started your swing. You could well be adjusting your swing during the contact time, but you are just doing it from the information you are continuing to receive before contact, not from the tactile feedback of the contact itself. Then after all that you get feedback from the contact to know what the nature of that contact was and how well you adjusted.

This is why the athletes continue to watch the ball, our brains are actually really bad at accurate kinematics. It's very quick, but it's not really calculating, it's just making an estimate. These estimates (both for the moving ball, and the internal pedometry of your own movement) are really inaccurate, and need you to be continuously adjusting off the incoming information. Even if they are not watching at the exact instance of contact, they are getting as much information as they can before that point to make their calibration as accurate as possible.