Dwell time

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I had forgotten about Hedgehog but he wrote great posts.

The reason I brought up head size is it could help answer what it is we feel on shots. The confounding thing from a physiology perspective comes from proprioception which I personally think is our most important source of "feel" in TT. How we sense muscle location and tension depends a bit on how heavily the muscle is loaded. Because larger blades are heavier, head size will affect feel in that way, while at the same time affects how the blade vibrates. So it is hard to tease out the separate contributions of those two factors. I think differences in how more heavily loaded loaded muscles and tendons sense length and tenson may be why we all think heavier blades generally play faster. (Or is it because they are actually slightly thicker and stiffer? The notorious pnachtway denied that heavier blades were faster at all based on Newtonian mechanics, which is the core of his professional expertise and the one thing he does know).
 
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I have another crazy theory based on coaching I have been getting lately, and also watching. This theory is that feel is vastly overrated. I will have to write it carefully and figure out how to put it into words. Key word of course is "theory".
 
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I had forgotten about Hedgehog but he wrote great posts.

The reason I brought up head size is it could help answer what it is we feel on shots. The confounding thing from a physiology perspective comes from proprioception which I personally think is our most important source of "feel" in TT. How we sense muscle location and tension depends a bit on how heavily the muscle is loaded. Because larger blades are heavier, head size will affect feel in that way, while at the same time affects how the blade vibrates. So it is hard to tease out the separate contributions of those two factors. I think differences in how more heavily loaded loaded muscles and tendons sense length and tenson may be why we all think heavier blades generally play faster. (Or is it because they are actually slightly thicker and stiffer? The notorious pnachtway denied that heavier blades were faster at all based on Newtonian mechanics, which is the core of his professional expertise and the one thing he does know).

In theory, the weight of the racket is too heavy compared to the ball, it's usualy taken out from the equation which I'm sure pnachtway has mentioned. Actualy, I'm interested in reading how pnatchway has calculated the ineffectiveness of the ball/blade weight ratio as the ball come at much higher speed than the racket.

Centrifugal force gained by top-heavy blade could contribute to the speed of the ball when it's combined by the rubber's throw angle. But I'm not sure. Like Curl said, heavier racket does seem to be faster but it could be false sense as there'll be less vibration. Again, I'm not sure as I haven't compared the speed by the apropriate instruments.
 
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@Der_Echte

Your translations of KJH's stuff and now providing us this is just too much.

You're the hero we all want but probably don't deserve. Do keep doing what you're doing. ;)
I am what I am and it isn't anything close to a certified hero, unless it is relatec to antics assisting Carl when he is getting his tail stuck in a Crack again while being pursued by the Goon Squad.

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There was a long thread on mytt a long time ago. It was by a someone named Anton it is was titled "an obscure question. It was all about dwell time.
First you must define what your definition of dwell time. Is is what you feel like Baal was suggesting, or is it the actual time where the ball is in contact with the rubber?

Baal has pointed out that the ball is long gone by the time you feel it.

pnachtwey used the contact definition of dwell time. That is dwell time is the time the ball is in contact with the rubber. There was no proof of what the dwell time was until pnachtwey posted high speed videos of the ball contacting the rubber.

On mytt Baal actually did a 'napkin' estimation of the dwell time given simple parameters. Baal's estimate was pretty good. Baal, do you remember that? Perhaps Baal should explain the calculations he made years ago.
 
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There was a long thread on mytt a long time ago. It was by a someone named Anton it is was titled "an obscure question. It was all about dwell time.
First you must define what your definition of dwell time. Is is what you feel like Baal was suggesting, or is it the actual time where the ball is in contact with the rubber?

Baal has pointed out that the ball is long gone by the time you feel it.

pnachtwey used the contact definition of dwell time. That is dwell time is the time the ball is in contact with the rubber. There was no proof of what the dwell time was until pnachtwey posted high speed videos of the ball contacting the rubber.

On mytt Baal actually did a 'napkin' estimation of the dwell time given simple parameters. Baal's estimate was pretty good. Baal, do you remember that? Perhaps Baal should explain the calculations he made years ago.
Maybe it's the contact time and of course the feeling of the ball while it's in the rubber. Btw, I'm planning to buy Darker Synergy Plus and put at 50 degree rubber on my FH. Is it good?
 
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The calculations I made were how long it takes for a nerve impulse to reach your brain from your hand and I compared that to what various people measured with high speed video for the actual dwell time. I cant recall who made the high speed video measurements though and I'm too lazy to go back and search for it. Pnachtway definitely has the technical skills to have done it. Maybe Butterfly did it too?``Thatbis the kind of thing Zeio always knows. I seem to recall that actual ball dwell was somewhere in the general range of 1 millisecond. The limitations of human nerves and synapses mean that long before your brain registers the ball hitting your blade (tens of milliseconds) it is well on its way back to the other side. So based on that I questioned what that feeling of dwell was in reality. Because we all get that sensation and it can vary with rubber or blade, and I have always supposed it is mainly to do with the duration of a blade vibrating or resonating as a result of the ball striking the blade. It caused a flame war from engineers who know a vast amount about mechanics but no physiology (which I teach at a university). With that said, I also believe that the actual dwell time has very real relevance to how a setup plays. I'm just very unconvinced that the FEELING of dwell has a simple relationship to actual dwell. (Actually it might but it doesn't have to and at the present it is unknown).

In fact on this very thread a couple of years ago I made some comments about all the complicated factors that are going to influence how something feels. Our bodies are amazing but sensory systems can get fooled.

At the end of the day, no matter how scientific you try to make a blade/rubber choice, only actually playing with it gives you the answer. I honestly have no idea what blade would pair best with a 50 degree rubber.
 
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The calculations I made were how long it takes for a nerve impulse to reach your brain from your hand and I compared that to what various people measured with high speed video for the actual dwell time. I cant recall who made the high speed video measurements though and I'm too lazy to go back and search for it. Pnachtway definitely has the technical skills to have done it. Maybe Butterfly did it too?``Thatbis the kind of thing Zeio always knows. I seem to recall that actual ball dwell was somewhere in the general range of 1 millisecond. The limitations of human nerves and synapses mean that long before your brain registers the ball hitting your blade (tens of milliseconds) it is well on its way back to the other side. So based on that I questioned what that feeling of dwell was in reality. Because we all get that sensation and it can vary with rubber or blade, and I have always supposed it is mainly to do with the duration of a blade vibrating or resonating as a result of the ball striking the blade. It caused a flame war from engineers who know a vast amount about mechanics but no physiology (which I teach at a university). With that said, I also believe that the actual dwell time has very real relevance to how a setup plays. I'm just very unconvinced that the FEELING of dwell has a simple relationship to actual dwell. (Actually it might but it doesn't have to and at the present it is unknown).

In fact on this very thread a couple of years ago I made some comments about all the complicated factors that are going to influence how something feels. Our bodies are amazing but sensory systems can get fooled.

At the end of the day, no matter how scientific you try to make a blade/rubber choice, only actually playing with it gives you the answer. I honestly have no idea what blade would pair best with a 50 degree rubber.

From a medical book in college, impulse conduction from any part of the body to the brain is 72m/s. I think it is fast enough to give you the "feel" of contact or "dwell".
 
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About the dwell time. What blade should you recommend that has dwell time that I can pair it with 50 degree rubber?

Honestly it comes down to what you are trying to do. TTgearlab is an interesting blog and there he argues that there is a concept of holding the ball based on the difference between the regular rebound of a blade and the central rebound. Maybe you want blades that hold the ball according go his definition and with lower speeds overall.
 
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Dwell time depends mostly on personal style, experience and techniques.
You may snap-hit the ball and the dwell may be a millisecond, or a part of the millisecond.
But you may take the ball, hold it, drive it and release it and the dwell would be several milliseconds, or hundreds of the second, or even tenths of the second.
Feel of the actual contact and nerve impulse speed is good to mention, but in reality there are much more factors that are involved in the dwell time control - vision, hearing, motor mechanics, all working in a system, depending on experience and technique.
 
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From a medical book in college, impulse conduction from any part of the body to the brain is 72m/s. I think it is fast enough to give you the "feel" of contact or "dwell".

Sigh. Not this again.

Yes, 70 to 100 M/sec for type A myelinated fibers. But you have at least 4 synapses before any information reaches the first neuron in the somatosensory cortex. Each synapse adds a delay of a little less than 1 msec. And there is extensive processing in somatosensory cortex before it becomes a perception. So even one or two synaptic delays is about the same order of magnitude as ball dwell time. Let's use simple numbers and ask order of magnitude questions. . Assume the hand is 1 M from brain, a nerve conduction velocity 100 M/sec and no synapses at all on the pathway. For a nerve impulse to reach brain takes 1/100 sec which is 10 milliseconds, or about an order of magnitude more than the estimated 1 millisecond ball dwell time. Add synapses and the fact that some of the neurons in the pathway will conduct a bit slower, and add the necessary processing in sensory cortex of brain and you realize there is no way one could feel a dwell of even 10 milliseconds. And there is no way ball dwell will be longer than that no matter how you hit it. In my professional live I have actually spent lots of time -- a couple if decades-- recording nerve impulses and synaptic delays so I have a pretty well evolved comprehension of 1, 10, or 100 msec (from traces on an oscilloscope screen or computer monitor). A 100 msec ball dwell is an utter absurdity. 10 msec is still probably longer than is likely for even the brushiest of brush loops.

I suspect part of the sense of dwell comes from varying racket angle (which you can feel using proprioception system) and how hard the ball is struck and players can see and hear how that effects the shot. It is really complicated but experienced players aren't doing it in "real time" so to speak. On the other hand they can still sort of figure out what happened before the ball strikes the opponent's side of the table. The sum total of all these sensory inputs kind of gives a cognitive impression of dwell, but is it accurate? Not known. Clearly we can feel the vibrations in the blade caused by striking the ball and our brain uses that information.

All this conversation is breaking a Rule though. Physiology is close enough to physics that this gets us nowhere. What I just wrote is reality-based. You want to believe something else? Feel free. I'm not going to respond.

I will just close with this: the only way to know if you will like a particular blade with 50 degree rubber is to try it. You're not going to be able to know for sure from Science.
 
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Dwell time, contact time, can be very long. People have posted videos of people catching the ball on their paddles. In that case the dwell time is practically infinite. Most of the time it is very short in the one millisecond range.

Accelerating the paddle through the ball increases the dwell time only a little but it depends on the speed of impact and acceleration.

What know one seems to ask
"what are the conditions for extending dwell time"
"what is the ball doing while it is in contact with the rubber?"
 
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The dwell time, contact time, can be quite long. People have posted videos where good players can catch the ball and hold it on their paddle. This provides for a potentially infinite dwell time.

No one asks:
"what is the ball doing during the contact time?"
"what conditions would extend dwell time?"
 
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