Dwell time

[Ilia Minkin]

Archosaurus translated what I wrote into something easy. We can't measure dwell directly with our hands. But maybe we measure something else that is related to dwell. The thing is, though, I don't think we know with 100% certainty if the thing was interpret as dwell has any relationship at all to actual dwell. I honestly can't even make an educated guess whether that idea is true or not.

What about our eyes? If the dwell time of one racket is higher than of the other one, we may notice with our eyes that the ball leaves the racket later since it holds in the sponge longer. Or our eyes are too slow for that?

 

[UpSideDownCarl]

Here: more good stuff about touch, grabbing the ball, dwell time and spin from KilerspinTT:

More than the sound, there is the ball trajectory and clearly the ball is going down instantly after than contact, it goes over the net only because the contact point is very very high. The real test of skill is to top spin this huge underspin ball with a contact point under the net, forcing you to create an arc.

I do think that if the bat speed matches the spin of the ball, you should get a returning spin not far from the incomming one, and it's obviously not the case here.....only judging from the bounce of the returning ball. It is possible to loop this ball by using "brut force", meaning as described by Pnachtwey, by reaching a very high paddle speed..........but it is also possible to loop this ball by touch.......has you described, by reaching a high dwell time (= "grabbing" the incomming spin).

Touch is everything in table tennis. I have faster arm speed on my FH loop than many of my team mates in my tt club, but a team mate is able to input incredible spin, more than me, even with is "slow motion" FH loop. He is able, thx to his touch, to deform the rubber even on "slow motion" strokes.

See this video of Shlager (serves) :

I do believe that anyone here can reach far higher bat speed on a pendelum serve than Schlager is using for most of his serves here. But nobody here is able to imput has much spin than Schlager. Thanks to his amazing touch, Schlager is able to input more deformation than us to his rubber, resulting to more spin than anyone of us, he is maximazing dwell time. And this is what you explain also at the end of your post, the acceleration is an important factor to reach a better dwell time/rubber deformation/higher spin.

As I said, yet another awesome post. Such good information from him.


Sent from the Subterranean Workshop by Telepathy

 

[UpSideDownCarl]

By the way, great posts Baal.


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[Baal]

What about our eyes? If the dwell time of one racket is higher than of the other one, we may notice with our eyes that the ball leaves the racket later since it holds in the sponge longer. Or our eyes are too slow for that?

I honestly don't know. I suspect hearing may be more important but I really don't know.

 

[waldner101]

So is "touch" something you develop as a player or is it natural/gift?

 

[NextLevel]

Baal,

I linked to a blog post in my initial response that talks about the different harmonic frequencies at which blades vibrate. Because of how this is related to blade stiffness and whether a blade gives me feeling or not, I have assumed for a long time that this is the key to dwell.

Carl to me still makes a great point. The contact times are short and the feeling of dwell is longer than the contact point times. But that does not mean that there is no correlation at all between extended contact time and the feeling of dwell.

 

[songdavid98]

So is "touch" something you develop as a player or is it natural/gift?

it could be a little bit of both, but you definitely can develop this as a player. touch is like, how you know whether or not you will make the shot as you swing.

 

[NextLevel]

When Brett tested the TTEDGE app on players he knew, the ones who had good touch often read the serves easily. The ones with bad touch or who had serve return issues struggled with the serves. And remember, this is on an app. No physical returning of the serves. His tentative conclusion was that good touch could be largely an ability to read spin and adjust accordingly.

 

[UpSideDownCarl]

I know practicing that against the edge of the table drill from the Marcos Freitas video really helped me develop softer hands and it definitely helped my touch.

But I don't think starting to play at 44 years old helped me out any. And when I first started I thought I was already good. I'm sure that didn't help me much either. But it was not hard to realize how bad I really was when confronted by decent players at a real club.


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[Baal]

Baal,

I linked to a blog post in my initial response that talks about the different harmonic frequencies at which blades vibrate. Because of how this is related to blade stiffness and whether a blade gives me feeling or not, I have assumed for a long time that this is the key to dwell.

...

But that does not mean that there is no correlation at all between extended contact time and the feeling of dwell.

1. I think the first time I made a post somewhere about blade vibrations at multiple frequencies and relation to peoples sensation of dwell was about 6 years ago. But of course it is a fairly obvious idea. I'm sure many people have had that idea.

2. Agreed. I even suggested in one of my long posts on this thread one way to approach testing it. But the fact is, something being possible and even beautifully plausible doesn't make it true. Our sense of dwell, from whatever it comes from, may not correlate with actual dwell. Or maybe not reliably.

 

[Baal]

When Brett tested the TTEDGE app on players he knew, the ones who had good touch often read the serves easily. The ones with bad touch or who had serve return issues struggled with the serves. And remember, this is on an app. No physical returning of the serves. His tentative conclusion was that good touch could be largely an ability to read spin and adjust accordingly.

That is a good point. We use a lot of senses when figuring this stuff out.

At the end of the day the two most important are vision (where the ball is and what it is doing) and proprioception (where we are, hand arm, balance etc.). Rememer, a dwell time of 1 millisecond means that by the time the ball strikes the bat it is too late for us to change what happens on that shot!!!!!!!!! Our reaction time is approx 100 times slower.

Touch is really precision of motor control and most of all knowing exactly what is the appropriate movement to make, ahead of time.

I honestly don't believe also that Schlager's serve is great because he has magical ability to have more dwell time than other people. In fact I very much think that is not the case.

 

[ttpshot]

Big thanks to everyone who's posted here. It's helped my understanding on the subject greatly. Will reply to individual posts as I have many more questions already.

 

[NextLevel]

1. I think the first time I made a post somewhere about blade vibrations at multiple frequencies and relation to peoples sensation of dwell was about 6 years ago. But of course it is a fairly obvious idea. I'm sure many people have had that idea.

2. Agreed. I even suggested in one of my long posts on this thread one way to approach testing it. But the fact is, something being possible and even beautifully plausible doesn't make it true. Our sense of dwell, from whatever it comes from, may not correlate with actual dwell. Or maybe not reliably.

1. Many people have had the idea, but you can actually test aspects of it at home using Audacity.
2. Yes, it may not. Science has many example of such things. But sometimes, the differences (mostly imprecision) are overhyped and the areas of agreement much downplayed. It's like pointing out some foods are carcinogenic but forgetting that in the larger scheme of things, they are still foods that quell hunger.

 

[NextLevel]

That is a good point. We use a lot of senses when figuring this stuff out.

At the end of the day the two most important are vision (where the ball is and what it is doing) and proprioception (where we are, hand arm, balance etc.). Rememer, a dwell time of 1 millisecond means that by the time the ball strikes the bat it is too late for us to change what happens on that shot!!!!!!!!! Our reaction time is approx 100 times slower.

Touch is really precision of motor control and most of all knowing exactly what is the appropriate movement to make, ahead of time.

I honestly don't believe also that Schlager's serve is great because he has magical ability to have more dwell time than other people. In fact I very much think that is not the case.

I don't think anyone called it "magical" - the main point is that there is a quality of contact which should be found and reproduced. Since I have gotten better at serving, I am not so sure that actual speed doesn't matter - my impression is that there are more efficient ways to produce that speed and contact (whip motions with rapid backswings which force the wrist to snap back and forth) that tend to be more efficient and difficult to see than larger motions with the body which might seem superficially faster over larger distances.

 

[Archosaurus]

Are we talking about speed or acceleration? I've always been under the impression that the rate of acceleration matters much more than the maximum velocity.

 

[Liten]

Reading the p-nut ramblings again makes me think of a recent meme on fb..
"Arguing with an engineer is like wrestling in the mud with a pig... after a couple of hours you realize the pig likes it"

 

[UpSideDownCarl]

Baal, what was your version of Liten's statement? I remember it but not the exact wording.

Something like: when you wrestle with a pig you are likely to get covered in mud.

But I think I am losing some of the meaning. I think the way it was worded was better.


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[Baal]

The classic version is "When you wrestle with a pig all that happens is you get covered with mud and the pig likes it".

It has many versions.

 

[James Livesey]

I think vibrations and sound are our two best sensory inputs. I don't think it has been mentioned, but vibrations make you very aware of where on the blade the ball has been. There is no doubt in my mind that there is more dwell time on chops or loops than flat hits. I can sense on loops that the ball has touched more of the blade, even though this is probably rather small in difference to flat hits. I know how much energy went into the ball from how fast I swung, so feeling that the ball traveled across the ball further indicates that that more energy was converted to spin than ball velocity. Furthermore, the sound is very different, especially when using a tacky, medium hard rubber (my fh). With my bh, a very soft euro type rubber, I hear less of a difference but feel it more, as on flatter hits the ball digs in deeper and transfers more energy directly to the blade so the vibration is more intense. I would argue that the reduced feedback from carbon blades is very detrimental to learning. I've tried carbons and they're faster and feel awesome but I don't think I would develop better strokes using them. I'd only consider them if I didn't want to get any better, which honestly, I don't see happening. Furthermore, I'm ph, so carbon etc is less viable for a lightweight, close to the table blade.

 

[ttpshot]

There is a classic post on this issue by killerspintt that Carl likes to quote - I hope he can find it. Killerspintt was responding to an arrogant engineer who likes to argue that dwell time is not important because it is the actual physical response is so short.

First of all, the sensation is related to the nature of the rubber and blade. The experiments this blog writer here proposes to the reader to perform with Audacity later in this blog post give you an idea of where the sensation of dwell is coming from:

https://thoughtsontabletennis.wordpress.com/2015/04/25/introduction-to-table-tennis-blade-design/

Secondly, just because the actual contact is supposedly short doesn't mean that the attempt to change the feeling doesn't have actual effects on the ball. It is like saying that only what happens when you hit the ball is important, forgetting that how you hit the ball requires a swing that accelerates, which often means that you need a backswing and a forward movement and a follow through, all of which affect how the ball is hit at contact since the swing is a continuous movement. The feeling of what happens matters, even if you think it does not.

Thank you for providing the link to the article altough it was not quite what I had in mind, it was a good read about how rebound and vibration is determined in particular blade.

I'm a great believer of the feeling too. Swing is very importand because we can't adjust our swing during dwell time. So you're saying feeling(feedback from the blade) matters because we adjust and improve our strokes according to the feel of the ball?