Ball Pocketing, Dwell Time, Spin Potential

[maxpotapov]

Originally Posted by treblings

thanks, really appreciate that you took the time to explain that to me.
i got a recommendation to try black widow a while ago. i guess i´ll try that combo with a smooth poly.

It also works with some sleek synthetic gut cross, such as Gosen OG Sheep Micro or maybe Babolat Nvy. Then you have spin and comfort for at least 3 hitting sessions, until those sharp edges smooth out plus string loses its elasticity.

[Bedrock]

Originally Posted by pvaudio

Dwell time is a subjective sensation and nothing more. The ball is on the stringbed for such a short period of time that your brain literally does not even get the information that there was a ball on the strings until after you've hit it.

really? ...

[maxpotapov]

Originally Posted by pvaudio

It's very odd. It's like it's braided almost. It's kinda lumpy rather than rough.

That's why my guess is those micro bumps kinda help sliding, think Dunlop Aeroskin

[sureshs]

Originally Posted by pvaudio

No. Objective is that the stiffness of the string is x. Its dwell time depends on the stroke type, the frame, tension, etc. It's a feeling, and cannot be measured. People on here often say x string has great dwell time, and then others disagree. If it was objective, then there wouldn't be a disagreement.

Most people here are not pros with a highly developed sense of feel.

Dwell time can and has been measured with high-speed photography and is about 4 milliseconds.

[treblings]

Originally Posted by maxpotapov

It also works with some sleek synthetic gut cross, such as Gosen OG Sheep Micro or maybe Babolat Nvy. Then you have spin and comfort for at least 3 hitting sessions, until those sharp edges smooth out plus string loses its elasticity.

thanks, i´ll make sure to remember your recommendations

[pvaudio]

Originally Posted by sureshs

Most people here are not pros with a highly developed sense of feel.

Dwell time can and has been measured with high-speed photography and is about 4 milliseconds.

Precisely my point. What is being discussed is a sensation: the sensation that the strings are cupping the ball or that the ball is sinking into the strings. The amount of time that the ball is on the stringbed is more or less the same regardless of string type.

[pvaudio]

Originally Posted by Bedrock

really? ...

Yup, as surehs said, the actual contact time is only a few 1/1000 of a second. The absolute maximum that a nerve impulse can travel is about 120m/s. That's the max velocity of neurons. In actuality, touch neurons travel around 75m/s and pain signals are much much slower. But even using a blazing fast 100m/s impulse that means that, assuming your hand is 1m from your brain, that it still takes 1/100 of a second to get there. That's over twice as long as the ball is on the strings. So literally, the ball is off the strings by the time the signal has reached your shoulder joint, so it is truly gone before you know it. That's not even including the time it takes to process the sensations from the thousands of receptors in your hand. So unfortunately for UCSF, it is impossible for you to change your grip as you're hitting the ball unless you started doing it before the ball was even close to your body.

[UCSF2012]

.

Originally Posted by pvaudio

Precisely my point. What is being discussed is a sensation: the sensation that the strings are cupping the ball or that the ball is sinking into the strings. The amount of time that the ball is on the stringbed is more or less the same regardless of string type.

Your point is a stupid one. Dwell time is not a sensation. A ball hitting a tennis racket produces a sensation, but that doesn't mean dwell time is a sensation. You may feel a sensation indicative of dwell time, but that's something else.

Dwell time is a property between the strings and the ball. It's irrelevant whether a player can feel it. Even in a person with anesthesia (unable to feel the ball impact) the ball will sit on the strings for a certain amount of time.

[UCSF2012]

Quick google search brought this up:


"The dwell time of the ball on the strings should increase as the inverse of the square root of the tension; measurements made in the lab bear this out. In addition, the dwell time of the ball on the strings decreases the harder the ball is hit, because the strings become effectively stiffer the more they are forced to deform...
The actual time of contact for a normal shot with normal string tension is about 4 or 5 thousandths of a second. By reducing the string tension and not hitting hard you might be able to increase the dwell time to about 6 or 7 thousandths of a second... These times are so much shorter than your reaction or reflex time that you cannot possibly do anything to change [the way you are hitting] the shot while the ball is on the strings... A longer dwell time also means that the shock of the ball being hit is spread over a longer time; the magnitude of the force at any given time is therefore reduced... If you wish to alleviate arm troubles such as tennis elbow, reducing the tension of your racket strings will not only lessen the initial shock transmitted to your arm but will give you more power from the racket. You will not have to swing so hard, which is kinder to your arm..."

In summary, pvaudio doesn't know jack. And I guess I was wrong about the touch volley exception. Perhaps I was just using a loose grip.

[UCSF2012]

There are a couple ways to increase dwell time: lower tension, add lead, and change string types (gut>multi>poly, given the same tension).

[pvaudio]

Are you seriously this dense, or do you just enjoy arguing for no reason? Everything you posted, EVERYTHING, supports what I've been saying. Dwell time and ball pocketing as being discussed here are a SENSATION. The fact that Genesis Black Magic and Typhoon produce more dwell time than say Prince Synthetic gut are simply sensational experiences. As your own information posted, the amount of variance in the time the ball spends on the strings is 1-2 milliseconds which you cannot even register. Seriously, I'm doing my best here to not just call you a troll because you do this in every single thread, but it's getting quite annoying. A one millisecond difference in time on the stringbed is measurable ONLY in a controlled situation, and depends on so many factors which vary from player to player, and yet certain strings are said to give more pocketing than others. That is a feeling, and nothing more. Your mind cannot even process a stimulus of 6ms as being longer than one of 4 or 5ms. Nerves simply are not able to respond that quickly. You're arguing as though that increase in contact time is what leads to the sensation of increased ball pocketing. Your nervous system literally is not sensitive enough to register that change. What you're experiencing is a complex series of vibrations and stimuli which give you certain feedback about how you hit the ball. Again, and hopefully for the last time, dwell time, pocketing, whatever you want to call it, is a sensation caused by a complex series of interactions. It is not the fact that the ball is actually sitting on the stringbed significantly longer for certain strings because even using the maximum variance of 3ms as posted in your information would not even register.

[pvaudio]

OP, let me make this as simple as possible. String up Genesis Typhoon, Dunlop Black Widow or Genesis Black Magic. Go for a hit. You will get that ball pocketing that you're talking about. String up Gosen OGSM. You will not get that same feeling. In both cases, the ball will be on the strings for fractionally longer with the Gosen than with the polys simply because the Gosen is more elastic. This is the point I have been trying to make all along. The sensation of pocketing and dwell is not due to the ball actually being on the strings for a longer period of time, to answer your initial question. It's due to how the strings respond to being hit, and how they send their reaction through the frame. Black Magic is well known to give the feeling that the ball sinks into the stringbed. Solinco Tour Bite or Signum Pro Tornado, however, are not known for great dwell time. However, the spin potential of Tour Bite is almost universally stated as being one of the greatest of all poly strings. So, if the amount of string bed contact is more or less the same across strings, let alone the same material, then no, dwell time does not increase spin potential.

[UCSF2012]

Given the publication, who's the dense one?

[pvaudio]

Let me also provide the reference for UCSF's paragraph since he cherry picked phrases at will:

http://books.google.com/books?id=iTa...ension&f=false

[UCSF2012]

I purposely didn't cherry pick. I included portions of the publication that showed where I was wrong. You say you can't increase the dwell time, but this publications stated they measured a dwell time increase of over 2x. Tell me again who's dense.

[NLBwell]

You obviously don't actually feel the ball on the strings. You feel the vibrations of the racket (racket/string system) which start as the ball contacts the strings and continues long after the ball has left the strings. A looser and/or more flexible string job will respond with lower frequency vibrations than a tighter stiffer string job. These vibrations will be correlated to the dwell time on the racket. Your brain can tell the differences between the vibrations, and then, through experience, will tell you that your are expericencing hitting the ball with a more flexible system (more rubber band-like) or a stiffer system (more iron-bar like).

[pvaudio]

Originally Posted by UCSF2012

I purposely didn't cherry pick. I included portions of the publication that showed where I was wrong. You say you can't increase the dwell time, but this publications stated they measured a dwell time increase of over 2x. Tell me again who's dense.

Quote me where I said you cannot increase the contact time with strings. I not once said that, nor would I as it has nothing to do with the topic at hand. What I DID say was that simply increasing the contact time by a few ms does not increase the feeling of dwell time. Obviously if you string at 60lbs and then at 30lbs you will get a much different sensation. As is your MO, what that has to do with this discussion, I haven't the faintest idea.

[pvaudio]

Originally Posted by NLBwell

You obviously don't actually feel the ball on the strings. You feel the vibrations of the racket (racket/string system) which start as the ball contacts the strings and continues long after the ball has left the strings. A looser and/or more flexible string job will respond with lower frequency vibrations than a tighter stiffer string job. These vibrations will be correlated to the dwell time on the racket. Your brain can tell the differences between the vibrations, and then, through experience, will tell you that your are expericencing hitting the ball with a more flexible system (more rubber band-like) or a stiffer system (more iron-bar like).

Of course they will be correlated. Even that does not mean that the ball spent more time on the racquet, however. Since UCSF just posted a reference, I'll just refer to that whereby if you're rallying hard, you get the feeling of dwell time much more than on a drop shot volley even though the ball spends less time on the strings during the rally. The only point that I've been trying desperately to get across to the OP is that strings which exhibit the feeling of longer dwell time do not necessarily have greater spin potential. The reason is because actual contact times are so similar, and strings, racquets, swing speeds and tensions are all dissimilar among players, and yet the feeling of dwell time for certain strings is pretty much well accepted. In other words: the feeling of pocketing does not necessarily imply greater spin.

[fortun8son]

Originally Posted by pvaudio

In other words: the feeling of pocketing does not necessarily imply greater spin.

Ummm....yeah.
The sidebar was interesting,though.

[WileyCoyote]

Thanks to all of you for helping me learn a lot. The biggest things I have learned are:

1. Never mention dwell time again.

2. Talk about ball pocketing instead. Objective laboratory ball pocketing, not subjective. Some of you seem to think ball pocketing increases spin potential. Maybe? It does for me because the "string/ball friction" is increased. I think of the strings wrapping around the ball like a v belt on a pulley. The greater the angle of wrap, the more "friction" is present.

3. A significant component of spin, particularly topspin as an example, is caused by the movement of the mains along the crosses during impact and their attendant spring back to their original position as the ball leaves the string bed. A minimal amount of "string/string" friction is best for this. More initial movement along the crosses is a good thing so long as the mains spring back to their original location.

4. The "string/string friction" example explains why my gut mains have so much less fraying with a smooth poly cross than with a gut cross.

5. We never got to the open versus closed stringbed, but I guess that can wait for another session. The open stringbeds would seem to have more ball pocketing for sure. Right?

Thanks again. Be sure and let me know if I have learned anything incorrect, as I am sure some of you will do.

Harry