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-   -   Ball Pocketing, Dwell Time, Spin Potential (http://tt.tennis-warehouse.com/showthread.php?t=444421)

WileyCoyote 10-30-2012 04:30 PM

Ball Pocketing, Dwell Time, Spin Potential
 
I am a bit confused about how the subjects in the title fit together.

I equate ball pocketing and dwell time in a string/frame combination and consider it a good thing. As in like what gut does.

The question is: Does increased ball pocketing and thus dwell time equal more spin potential?

Reading the threads on rackets that provide more spin potential, fewer strings are usually, but not always, cited as providing more spin potential. Is this perhaps because the ball penetrates farther into the stringbed and has more string in contact around it to impart spin?

However when I read threads on Polys, which would have the least ball pocketing and dwell time, most of them claim to produce more spin than other kinds of strings. True? Not true?

Or what?

Thanks in advance for your intelligent and well reasoned answers.

Harry

pvaudio 10-30-2012 04:43 PM

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.

LeeD 10-30-2012 04:50 PM

Does "spin potential" have anything to do with better play?
Are you buying the Steam98?

UCSF2012 10-30-2012 08:56 PM

Increased dwell time increases power but decreases spin.

It's largely irrelevant whether the human brain can sense ball impact as it's occuring. It's not like you're gonna change your swing during the split second of impact. (Except for touch volleys.)

In fact, your nervous system is fast enough to detect the split second the ball hits the racket. The nervous system is ridiculously fast. The basis for touch/drop volleys is softening up on the grip during impact, so the ball dies.

WileyCoyote 10-31-2012 05:31 AM

OK. Maybe my brain is not fast enough to recognize dwell time, but it is a major parameter for TW string data, so it must be indicative of something.

The difference between a really tight poly bed and user friendly gut is very noticable and would seem to imply longer contact times with a more resilient string. Correct?

My understanding of spin is that it is produced by the movement of the racquet while the ball is in contact with the stringbed in such a way that imparts rotation. The longer the contact, the more rotation should be imparted?

Thanks,

Harry

maxpotapov 10-31-2012 05:52 AM

Quote:

Originally Posted by WileyCoyote (Post 6985482)
OK. Maybe my brain is not fast enough to recognize dwell time, but it is a major parameter for TW string data, so it must be indicative of something.

The difference between a really tight poly bed and user friendly gut is very noticable and would seem to imply longer contact times with a more resilient string. Correct?

My understanding of spin is that it is produced by the movement of the racquet while the ball is in contact with the stringbed in such a way that imparts rotation. The longer the contact, the more rotation should be imparted?

Thanks,

Harry

On a high speed camera you can see how mains are sliding on impact if you hit a top spin shot. That means, the ball slides first and then displaces the mains. When mains snap back, they launch the ball back at certain angle. All of this takes time, dwell time. And of course the frame itself is deformed under pressure, and stringbed too, while ball is sliding on the string surface.
The sharper the poly, the longer it can be pushed by the ball if the cross string is sleek enough. It takes less effort to displace natural gut due to high elasticity, especially on a sleek cross string, hence you can get quite a spin from the smooth natural gut string, but not from the smooth multi (not enough elasticity to easily slide back and forth).

treblings 10-31-2012 05:59 AM

Quote:

Originally Posted by maxpotapov (Post 6985516)
On a high speed camera you can see how mains are sliding on impact if you hit a top spin shot. That means, the ball slides first and then displaces the mains. When mains snap back, they launch the ball back at certain angle. All of this takes time, dwell time.
The sharper the poly, the longer it can be pushed by the ball if the cross string is sleek enough. It takes less effort to displace natural gut due to high elasticity, especially on a sleek cross string, hence you can get quite a spin from the smooth natural gut string, but not from the smooth multi (not enough elasticity to easily slide back and forth).

hope you donīt mind if i join the discussion:)
if i understand you correctly, your point is that the smoother the strings are, the more topspin they produce? provided they snap back(poly more so, multi less)

pvaudio 10-31-2012 06:06 AM

Quote:

Originally Posted by UCSF2012 (Post 6985134)
Increased dwell time increases power but decreases spin.

It's largely irrelevant whether the human brain can sense ball impact as it's occuring. It's not like you're gonna change your swing during the split second of impact. (Except for touch volleys.)

In fact, your nervous system is fast enough to detect the split second the ball hits the racket. The nervous system is ridiculously fast. The basis for touch/drop volleys is softening up on the grip during impact, so the ball dies.

Edit: not even worth it.

To the OP: dwell time is not an important TW parameter because there is no way to state it as the measure of anything. The TW spin parameters are stiffness, ball-string friction, string-string friction and perhaps one more. None are quantified as the time the ball spends on the strings.

maxpotapov 10-31-2012 06:08 AM

Quote:

Originally Posted by treblings (Post 6985522)
hope you donīt mind if i join the discussion:)
if i understand you correctly, your point is that the smoother the strings are, the more topspin they produce? provided they snap back(poly more so, multi less)

The smoother/sleeker the CROSS strings are and the sharper or more elastic MAINS, the more spin you can get. Or enter super open string patterns to reduce friction with crosses.

treblings 10-31-2012 06:11 AM

Quote:

Originally Posted by maxpotapov (Post 6985537)
The smoother/sleeker the CROSS strings are and the sharper or more elastic MAINS, the more spin you can get. Or enter super open string patterns to reduce friction with crosses.

thanks, i think i get that.
where does rough poly come in(as in alu power rough or msv hex,...)
in regard of spin? in the mains? is that what you mean by sharper?

maxpotapov 10-31-2012 06:17 AM

Quote:

Originally Posted by treblings (Post 6985539)
thanks, i think i get that.
where does rough poly come in(as in alu power rough or msv hex,...)
in regard of spin? in the mains? is that what you mean by sharper?

By sharper I mean strings like Dunlop Black Widow (7 sided profile), Polystar Turbo (star shaped profile) and alike. Alu Power Rough is successfully used as a cross string for natural gut, probably because "rough" texture on a harder surface actually reduces friction (it becomes less sticky or something).

pvaudio 10-31-2012 09:26 AM

Quote:

Originally Posted by treblings (Post 6985539)
thanks, i think i get that.
where does rough poly come in(as in alu power rough or msv hex,...)
in regard of spin? in the mains? is that what you mean by sharper?

Rough poly is exploiting the ball-string friction parameter. The higher this is, the greater the spin potential. The lower the string-string friction, the greater the spin potential. Interestingly, we have two counter examples to look at then using the same set of data. A stiffer string, according to TWU data, is more likely to be a better spin string. Thereby poly will provide more spin potential than synthetic gut or multifilaments. However, a moreelastic string will also provide more spin potential. These two concepts are not the same. To make it more clear, let me define the two. Stiffness is the ability for a material to not deform or to resist deformation when under stress. Elasticity is the ability for the material to return to its original state after being deformed by stress. So, we're at an impasse: we want a string which does not deform under stress, but one which when it does deform, it returns to its original shape. This is why polyester is so popular for spin. It is very stiff, but yet it has a surprising amount of elasticity.

Once that elasticity is gone from usage, then the string's performance is lessened. If you have a rough string which can hold onto the ball while the string is deforming, you can return more energy to it. BUT! If the sliding friction is too high, or the friction trumps the string's elasticity, then it doesn't matter as much. That's why while natural gut is overall the best for spin next to poly, it still suffers from high string-string friction. Therefore, you want something with elasticity in the mains that bites onto the ball and something smooth in the crosses so that the mains can move more freely. This is the reasoning behind the gut/poly hybrid. If you put a rough poly main with a smooth poly cross, you can theoretically get similar results: you get great stiffness from the mains, and good ball-string friction, and low sliding friction just like with gut/poly.

pvaudio 10-31-2012 09:28 AM

Quote:

Originally Posted by maxpotapov (Post 6985546)
By sharper I mean strings like Dunlop Black Widow (7 sided profile), Polystar Turbo (star shaped profile) and alike. Alu Power Rough is successfully used as a cross string for natural gut, probably because "rough" texture on a harder surface actually reduces friction (it becomes less sticky or something).

I think it's just because people prefer the feel of ALU Rough to ALU. They don't feel the same.

sureshs 10-31-2012 09:32 AM

Quote:

Originally Posted by pvaudio (Post 6984776)
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.

But you remember it for the next time around. That is how it is objective and not subjective.

maxpotapov 10-31-2012 09:34 AM

Quote:

Originally Posted by pvaudio (Post 6985949)
I think it's just because people prefer the feel of ALU Rough to ALU. They don't feel the same.

I did not use Alu Rough, is it sandpaper-rough to the touch or just textured?

treblings 10-31-2012 11:02 AM

Quote:

Originally Posted by maxpotapov (Post 6985546)
By sharper I mean strings like Dunlop Black Widow (7 sided profile), Polystar Turbo (star shaped profile) and alike. Alu Power Rough is successfully used as a cross string for natural gut, probably because "rough" texture on a harder surface actually reduces friction (it becomes less sticky or something).

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 iīll try that combo with a smooth poly.

treblings 10-31-2012 11:05 AM

Quote:

Originally Posted by pvaudio (Post 6985946)
Rough poly is exploiting the ball-string friction parameter. The higher this is, the greater the spin potential. The lower the string-string friction, the greater the spin potential. Interestingly, we have two counter examples to look at then using the same set of data. A stiffer string, according to TWU data, is more likely to be a better spin string. Thereby poly will provide more spin potential than synthetic gut or multifilaments. However, a moreelastic string will also provide more spin potential. These two concepts are not the same. To make it more clear, let me define the two. Stiffness is the ability for a material to not deform or to resist deformation when under stress. Elasticity is the ability for the material to return to its original state after being deformed by stress. So, we're at an impasse: we want a string which does not deform under stress, but one which when it does deform, it returns to its original shape. This is why polyester is so popular for spin. It is very stiff, but yet it has a surprising amount of elasticity.

Once that elasticity is gone from usage, then the string's performance is lessened. If you have a rough string which can hold onto the ball while the string is deforming, you can return more energy to it. BUT! If the sliding friction is too high, or the friction trumps the string's elasticity, then it doesn't matter as much. That's why while natural gut is overall the best for spin next to poly, it still suffers from high string-string friction. Therefore, you want something with elasticity in the mains that bites onto the ball and something smooth in the crosses so that the mains can move more freely. This is the reasoning behind the gut/poly hybrid. If you put a rough poly main with a smooth poly cross, you can theoretically get similar results: you get great stiffness from the mains, and good ball-string friction, and low sliding friction just like with gut/poly.

great info, thanks. when i saw your long post, i thought it would go over my head, but you explained it very clearly.
when people say, that a poly is dead, are they then referring to the fact, that it loses the elasticity to snap back?

pvaudio 10-31-2012 11:24 AM

Quote:

Originally Posted by sureshs (Post 6985960)
But you remember it for the next time around. That is how it is objective and not subjective.

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. All parameters that we look for in strings are subjective, but most are based on objective things. Comfort, power, spin, control, these are all subjective things. Stiffness, tension stability, durability and cost don't change depending on the player (durability is a bit of a stretch, but a 1.35mm poly is going to last longer for all players than a 18g syn gut). This is why we talk about spin potential, energy return, stringbed stiffness, etc. These things are more or less measurable and give an objective view of what we really feel.

pvaudio 10-31-2012 11:27 AM

Quote:

Originally Posted by treblings (Post 6986119)
great info, thanks. when i saw your long post, i thought it would go over my head, but you explained it very clearly.
when people say, that a poly is dead, are they then referring to the fact, that it loses the elasticity to snap back?

No prob! I should state at this point that I DO understand dwell time and that some strings provide more than others. It's just a certain feeling that you get. The reason I'm going on about this is because it's misleading to discuss it as though it changes your amount of control over your shots. Crisp and responsive strings don't exhibit it, but softer strings tend to.

And yes, death is that loss in elasticity.

pvaudio 10-31-2012 11:27 AM

Quote:

Originally Posted by maxpotapov (Post 6985964)
I did not use Alu Rough, is it sandpaper-rough to the touch or just textured?

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


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