All about dwell time, maybe, but only if there are enough people interested.

[Pnachtwey]

I got zero problem with Pnchy trying to explain the different aspects of impact dynamics.

....
This is derailing the thread.

However, don't be misled. The guy who started this thread is posing as if he has information, but the knowledge and calculations he has presented so far are the kind of thing that a 16 year old school physics student with a poor grasp of the material would say

If 16 years old could understand then why hasn't this issue been resolved long ago? From above it is obvious there are some concept you don't understand.

"i find the main reason for so many disagreements between pnachtway and everyone else is that he takes everything
literally. ......

Yes, engineers must be precise and what people think happens is irrelevant. What actually happens is what we should strive to know.

USDC, you post is off topic and adds nothing to the debate.

Back on topic.

Lets assume the rubber is somewhat linear. The ball at rest depresses the rubber a little when the there is only the force due to gravity. Lets say 0.01mm. When the ball is accelerated at 9.807m/s^2 and the force between the rubber and ball doubles the amount the ball sinks into the rubber doubles to 0.02mm So how far does the ball depress the rubber if I accelerate the paddle upwards at only 1/2 g? This should be simple.

 

[Suga D]

Oh no, when we get into that stuff, the scheize tends to hit the fan... Brace Urselves.

Ahahahaaa

Couldn't resist to picture this. So...

 

[izra]

Yes, engineers must be precise and what people think happens is irrelevant. What actually happens is what we should strive to know.

USDC, you post is off topic and adds nothing to the debate.

what people think happens is sometimes just a simple (albeit made up) explanation of something far too complicated to explain for (and to) most people. also in table tennis subjectivity should NOT be factored out but used to make the performance better. for example, as a coach i sometimes tell people to overdo certain body movements to a ridiculous degree just because they have a completely distorted picture of what their bodies are doing at a certain moment. also often times the biomechanics of table tennis strokes are counter intuitive (like which muscle groups and/or joints to use for which shot) and you first have to drill into the player something that doesn't make sense from their point of view, but with years of training it will become obvious to them through "feeling" the shot even without them ever grasping the biomechanics of it.

trying to teach someone table tennis through exact explanations is like trying to teach a child how to swing from branch to branch by explaining physics to it instead of giving it a shot at an actual tree.

Back on topic.

Lets assume the rubber is somewhat linear. The ball at rest depresses the rubber a little when the there is only the force due to gravity. Lets say 0.01mm. When the ball is accelerated at 9.807m/s^2 and the force between the rubber and ball doubles the amount the ball sinks into the rubber doubles to 0.02mm So how far does the ball depress the rubber if I accelerate the paddle upwards at only 1/2 g? This should be simple.

0.015mm?

 

[TT_Rogue]

How does one argue with that? What assumptions and definitions are wrong? Be specific.
The case where the ball is resting on the blade seemed to be simple enough that Grandpa accepted it.
This is why I get pissed and call people idiots. They throw stones without making a good counter argument. The problem is that few can.

You have wasted my time and bandwidth. I should have added to the title to this thread to "and they aren't idiots"

Be smart guys and back up you claims with facts. Grandpa is at least trying.

No. I think you are trapped in your mindset and it doesn't matter what i would tell you, it would be wrong to you.
But it makes me curious and I totlay would like to see you play table tennis, in german there is a saiying,
show me how you play and i tell you who you are. From your style i could immediatly tell if you are really like
you are showing to us here or if you simply like to fight or discuss with people.

 

[izra]

No. I think you are trapped in your mindset and it doesn't matter what i would tell you, it would be wrong to you.
But it makes me curious and I totlay would like to see you play table tennis, in german there is a saiying,
show me how you play and i tell you who you are. From your style i could immediatly tell if you are really like
you are showing to us here or if you simply like to fight or discuss with people.

there are already videos of him on here, he is a complete amateur with absolutely no insight from a players perspective but that still doesn't mean he is wrong when it comes to crude physics. what i believe his actual weakness to be is biomechanics, because when you add different muscles and joints and tendons into the equation, an action as simple as throwing a javelin becomes incredibly complex.

 

[passifid]

haha Pnatch getting a taste of his own medicine... no force due to acceleration is correct but in a stupidly nonsense and pedantic way of round about nonsensical science definitions.

i think he is saying acceleration in itself doesn't produce a net force on another object merely that acceleration is the result of an application of force. for example if you consider DWELL to be so low than we can consider acceleration almost moot right?(well no)
but the point is if a bat accelerating at 2m/s/s hits a ball at 5m/s at a weight of 200g it will produce a reasonably similar result to a bat accelerating at 3m/s/s if contact is also at 5m/s with a weight of 200g (i belive you said dwell was around 1ms bfore but who knows) because of the short dwell its basically a moot factor as long as you know impact speed.

but this is way above my physics grade so i'll butt out i just found it funny grandpa did a pnatch to pnatch and he thought he was being an idiot(can we call idiot by proxy?)

 

[TT_Rogue]

there are already videos of him on here, he is a complete amateur with absolutely no insight from a players perspective but that still doesn't mean he is wrong when it comes to crude physics. what i believe his actual weakness to be is biomechanics, because when you add different muscles and joints and tendons into the equation, an action as simple as throwing a javelin becomes incredibly complex.

In this case his mistake lies not in this. He has a big error in his assumptions. He wants to speak about a material relied characteristic, the dwell time of a wood. If we want to know about this characteristic we are doing a simple test. We are laying the racket down for example and we drop the ball from 1m height on it. From how far the ball bounces back we can aproximate how the dwell behavior of the racket will be. If we want to compare blades we repeat the test under same conditions. But he is abstracting that unecessary as hard as possible with putting rubbers on it, movements and then speaking about an infinite dwell time what nobody gives a f*ck about because the knowledge about that has no value to us. We are testing here a characteristic what we call dwell time and if you change everytime the conditions for it you cant compare anything and it loses every sense. That is what he is not understanding because he went nerd-beast-mode. And you will see what answer i will get for this post

 

[UpSideDownCarl]

But it makes me curious and I totlay would like to see you play table tennis, in german there is a saiying,
show me how you play and i tell you who you are.

TT_Rogue, I already posted a video of him playing. But since you didn't get my post advising you to run and hide, here is the man himself:

Here is the best one. Try to critique his form. I have heard tell that in this next one he is looping the ball with massive spin. And those high things he is hitting, that is backspin:

Please note the weight transfer in the last video. Highly technical skill to get so much spin that it bounces exactly like it would if there were none.


Sent from Deep Space by Abacus

 

[Archosaurus]

I would not like to talk bad about anyone who at least puts themselves out there to be critiqued, but I must say that the man's body is definitely not helping him produce good strokes. I can imagine how taxing it would be to shift a load like that.

To correct one's form, they should go to the root of the problem.

Grip pressure at impact has a lot to do with the result and it is likely the most under-rated and least discussed thing in Table Tennis stroke and impact dynamics.

Is grip pressure really such an advanced concept?

Long ago, I was told that most people grip the bat too tight, and thus I started gripping the bat harder and softer depending on the shot I'm playing, erring to grip the bat very relaxed as a default. If you took it out of my hand, I wouldn't even notice or resist getting the bat taken, is what I was told is the right pressure.

Then, I started finding out that you want to vary grip pressure on different parts of the stroke, and on different strokes overall, thus things like "hard blocking" and "soft blocking" are possible.

Now I can't even understand how anyone could get anything consistently on the table if they don't understand and apply grip pressure.

Perhaps I'm a "better player" than I think I am, which is probably unlikely, or the general level is lower than what I assumed it to be. I thought that grip pressure is basically the only thing you're really somewhat consciously paying attention to when you're stroking and that it's common to do it.

 

[vvk1]

Okay guys. First off, RUN. Second off, run faster. Stay away. This is a trap. Nobody wants to be caught arguing with a menstruating woman; especially when she is trapped in the body of the planters mascot.

Pnachtwey, you have been so good for the last few months. You haven't called anyone an idiot in so long. Don't let the autism get the better of you. And let us all know when you are off the estrogen therapy.

If you didn't already know here is Pnachtwey's specially developed technique for creating as little dwell time as possible.

Sent from Deep Space by Abacus

So, aside from personal attacks on pnachtwey, what was the point of this post? And you consider yourself better than him?

 

[Der_Echte]

So, aside from personal attacks on pnachtwey, what was the point of this post? And you consider yourself better than him?

That is a good point... if you never saw the previous year of stuff. Carl will likely pop on this thread again.

For the record, Carl's match playing level is at least 2, likely 3 levels above Pnchy. That stuff is never a justification for salty posts, but there might be a pile of posts from last year you never saw that would shed a little light on this vibe.

 

[Der_Echte]

I would not like to talk bad about anyone who at least puts themselves out there to be critiqued, but I must say that the man's body is definitely not helping him produce good strokes. I can imagine how taxing it would be to shift a load like that.

To correct one's form, they should go to the root of the problem.



Is grip pressure really such an advanced concept?

Long ago, I was told that most people grip the bat too tight, and thus I started gripping the bat harder and softer depending on the shot I'm playing, erring to grip the bat very relaxed as a default. If you took it out of my hand, I wouldn't even notice or resist getting the bat taken, is what I was told is the right pressure.

Then, I started finding out that you want to vary grip pressure on different parts of the stroke, and on different strokes overall, thus things like "hard blocking" and "soft blocking" are possible.

Now I can't even understand how anyone could get anything consistently on the table if they don't understand and apply grip pressure.

Perhaps I'm a "better player" than I think I am, which is probably unlikely, or the general level is lower than what I assumed it to be. I thought that grip pressure is basically the only thing you're really somewhat consciously paying attention to when you're stroking and that it's common to do it.

You are of course right, grip pressure is a really easy to understand thing in concept, but how to change it at impact is rarely discussed when explaining how to produce a certain ball.

The concept certainly is nothing now, but the way I see many players miss shots, many don't get it.

I am talking about the pressure of the grip at impact.

EDIT: I see you "get it" about grip pressure at impact and many good amature players get it and execute it without thinking about it.

Many different ways to grip it at impact to produce a different ball. Grip pressure is a difficult thing to measure on a TT bat and varies considerable. That part is difficult to quantify, but it has a lot to do with the result.

You block a ball close to table off the bounce (just holding the bat with zero forward movement at impact) with a very loose grip on BH vs a smash, it will go back kinda medium speed or slower and safe.

You try blocking the ball from the same spot off the bounce with even a medium firm grip, it will fly long/out. You back off a bit and let it come to a tad over net height and you hold it medium firm or more, you get a fast block that has a good chance of landing.

 

[UpSideDownCarl]

So, aside from personal attacks on pnachtwey, what was the point of this post? And you consider yourself better than him?

Well, the actual purpose was:

1) to be a clown and entertain myself.
2) to warn people who don't already know Pnachtwey that sometimes he likes to argue and to set up scenarios where only he can be right. And therefore arguing with him is a mistake.

But it was more about entertaining myself. I doubt there is much that will change the idea that Pnachtwey will act as though anyone who engages with him is an idiot and that he knows much more than everyone else. In reality he knows a lot. But the people skills....well, you can decide for yourself.


Sent from Deep Space by Abacus

 

[UpSideDownCarl]

That is a good point... if you never saw the previous year of stuff. Carl will likely pop on this thread again.

I'm pretty sure vvk1 was around for that. But I really was just joking around. So, in a way he has a good point. But I was hoping to get people to laugh and stop arguing.


Sent from Deep Space by Abacus

 

[TTFrenzy]

Dwell time seems to be a hot topic among TT players but honestly I bet NO ONE really anything about it. All they know is the myths perpetuated by the TT forums.

Let me start by saying dwell time can be infinite. If your paddle is horizontal to the ground and you place a ball on it it will stay there indefinitely until you tilt the paddle. The dwell time is infinite. This is an extreme case but it is a simple case. If the ball is stationary that means there is no net force acting on it. The force of the sponge pushing up on the ball is equal to force downwards due to gravity. This is a fundamental concept that the stupid physics PhDs and moderators on other forums don't seem to be able to grasp.

You can see that in this case having infinite dwell time really doesn't help with generating speed or spin.

If anybody wants to learn more I will explain more and try to keep it simple.

no shit sherlock

 

[Archosaurus]

You are of course right, grip pressure is a really easy to understand thing in concept, but how to change it at impact is rarely discussed when explaining how to produce a certain ball.

The concept certainly is nothing now, but the way I see many players miss shots, many don't get it.

I am talking about the pressure of the grip at impact.

EDIT: I see you "get it" about grip pressure at impact and many good amature players get it and execute it without thinking about it.

Many different ways to grip it at impact to produce a different ball. Grip pressure is a difficult thing to measure on a TT bat and varies considerable. That part is difficult to quantify, but it has a lot to do with the result.

You block a ball close to table off the bounce (just holding the bat with zero forward movement at impact) with a very loose grip on BH vs a smash, it will go back kinda medium speed or slower and safe.

You try blocking the ball from the same spot off the bounce with even a medium firm grip, it will fly long/out. You back off a bit and let it come to a tad over net height and you hold it medium firm or more, you get a fast block that has a good chance of landing.

I'd also like to add that you can change blade angle and fade/hook amount by varying the pressure each finger applies.

Most people seem to do this in the incorrect way, and they grip the bat hard and thus change the angle and amounts of fade/hook in the shot mid-swing. Good players do this unconsciously and the angle and amounts change properly to produce a good shot.

Couple this with tensing of the wrist and forearm and you can understand why pros produce such a different result from us.

I'm very interested in how people use arm and finger tensing to produce a shot. I haven't quite mastered this myself, and it more so happens "because" it happens, so if anyone has any knowledge, do share.

 

[Giangt]

I'm pretty sure vvk1 was around for that. But I really was just joking around. So, in a way he has a good point. But I was hoping to get people to laugh and stop arguing.


Sent from Deep Space by Abacus

I think I need to step in here... I'm pretty sure you were trying to clown around here, but communicating through text makes it hard to see or heard how ppl on the other are expressing themselves. I hope you get my point.

To the topic Dwell time. There are many factors which have influence on the dwell time of the ball.
Some of them are mention in the thread and some are not. I think most of the ppl here do not have the preconditions to say if the physics are right or wrong and I do not think they really care. What mortal ppl can relate to is if the dwell time is low, medium or high.

If someone wants to do a in depth analysis of dwell time in the TT world then the report should contain every single rubber in combination every single blade, do the math and verify that through test.

I would really like to see that report! Until then please be moderate here TTD-members.

 

[TT_Rogue]

TT_Rogue, I already posted a video of him playing. But since you didn't get my post advising you to run and hide, here is the man himself:

Here is the best one. Try to critique his form. I have heard tell that in this next one he is looping the ball with massive spin. And those high things he is hitting, that is backspin:

Please note the weight transfer in the last video. Highly technical skill to get so much spin that it bounces exactly like it would if there were none.


Sent from Deep Space by Abacus

DUUUUUUUUUUUUUDE, i thought you are kidding around and you posted just some random youtube video. Ok that got me. But unfortunatley it doesnt shows him in a match. Like this i cannot say anything. It is admirable that nevertheless of his shape he is obviously trying to improve. I wanted to see something like that the ball is jumping high from his racket and he is complaining that there appeared shortly a black hole above his racket that wanted to suck the ball in itself because it was cleary a backspin ball and it had to fall down and not jump upwards

 

[vvk1]

That is a good point... if you never saw the previous year of stuff. Carl will likely pop on this thread again.

For the record, Carl's match playing level is at least 2, likely 3 levels above Pnchy. That stuff is never a justification for salty posts, but there might be a pile of posts from last year you never saw that would shed a little light on this vibe.

I have read it all - both here and on mytt. And munched through a lot of popcorn watching the mudslinging. So, btw, thanks for the free entertainment to everyone who participated.

For the record, I am fully aware that both you and Carl are much better players than pnachtwey.

However, anyone who is honest with himself, even Carl, will admit that pnachtwey made an effort to become a better member of this community over the past months. In particular, there was nothing in his posts in this particular thread that justified the response from Carl I referred to above. Also the word "better" did not refer to anyone's playing level, just their behaviour on this forum.

 

[Der_Echte]

Archo... those subtle things that good players do intuitively are rarely discussed like it is a national secrets that will prompt the dispatch of a dozen goon squads.

I have been clear about the usefulness of discussing the topic of impact and dwell.

I was Pnchy's level when I started tt forming and better players likely giggled at a lot of what I tried to contribute.

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