Ball Pocketing, Dwell Time, Spin Potential

[ChicagoJack]

Hi Wiley,

I was watching the thread develop through out my work day, had no time to respond and was kinda waiting for the dust to settle anyways. Apologies for the long read. Hard to do a complex subject like this justice with a few sentences. Just three main topics for me here. 1 : Measuring Dwell and Deflection. 2. Dwell and Spin. 3. Dwell and Control.

Issue 1: Objectively Measuring Dwell Times & String Bed Deflection :

1a. One of the early statements in the thread that took the conversation into a very argumentative place was that dwell time could not be measured, is strictly a feeling, nothing more, therefore the term should be banished to the realm of the subjective, and dealt with entirely from that perspective alone. The data reveals ridiculously minor differences, but both Dwell time and string bed deflection are measurable. See screen grabs below. If you want to make a case that the differences are so minor that they are likely not perceivable to the player, or that dwell time isn't perceivable at all, then I just put $10.00 in to the basket on that sermon. If one's thesis is that dwell time has got very little to do with spin, amen to that my brother! But that's a whole 'nuther can of worms. Plenty of reasons to poo poo the concepts of pocketing and dwell time if one had the inclination, (many of which I agree with) but lack of objective measurements, isn't one of them. Not calling out PvAudio here, he's largely been the voice of reason and good information through out the whole thread, just pointing out this one dark corner of the TW University String Database that might have been overlooked.

1b. The dwell times read about 5-6 times longer than typical on court impacts of 4-6 ms. That's because the object striking the strings in the tests for stiffness, tension, deflection, etc. is a test hammer, not a ball. This is takes the ball out of the equation, and gets to the heart of what the string is doing. Balls lose pressure every second, change texture with repeated impacts etc... not good for getting clean data. One might choose to de - ligitimize the measured dwell times for this reason, but you'd have to throw out just about everything else we've measured too (stiffness, tension loss, deflection, energy return) in exactly the same way. Also worth a mention, notice the "actual pre - impact tension". This column demonstrates the tension after the string had a good number of whacks (I forget how many) with the test hammer, at levels simulating a 120 mph serve. Poly loses a bunch of tension in those pre-test whacks, while gut retains much more, yet still manages a deeper pocket and incrementally longer dwell times. Gut, thou art amazing.

1c. Pocketing and dwell times are often inversely related. You'd think that when the ball sinks very low into the strings, then it's going produce a longer dwell time. That's not always the case. QUOTE: "It's counter - intuitive but the harder you hit the ball, the shorter the dwell time. You somehow have a picture in your mind of a harder hit ball sinking deeper into the string bed, and therefore taking a longer time to come out. What actually happens is that the harder you hit the ball, the stiffer the strings get, as does the string plane. Even though the ball sinks in more, it also snaps back sooner due to the increase in string plane stiffness"-- Howard Brody, The Physics And Technology Of Tennis, Chapter 26.






[..]

Issue 2 : Dwell Time and Spin, IE.. "wrapping around the ball like a belt on a pulley"

2a. I follow your line of reasoning, and its a common thought process. You are thinking that deeper pocketing provides better grip on the ball, and better grip provides for more spin. It's a common conception but you have got some slightly faulty mental imagery. In the sport of table tennis, in which the ball does not squash, and the incidence angles are very steep, ball grip is a very big factor. In tennis however, not so much. Consider that the ball squashes flat like a bug on a windshield to roughly 1/2 its original size on impact. When you are able to see what actually happens with ultra high speed cameras, (See ITF Technical Video Provided) the tennis world becomes a strange and beautiful place indeed. The ball is a whole lot of shapes when it smashes into the racquet, but one shape it isn't, is round!. If the forces are great enough the ball can squash so firmly into the string bed that it's nearly flat, with the back of the ball bouncing off the front of the ball. The ball jiggles, the ball shakes and wobbles like a bowl of jello as it exits the string bed. Within this 4-6 ms time frame, all manner of strange things are occurring, and we... are utterly oblivious.

2b. We've learned within the last 5 years that spin enhancement is a product of 2 factors. ball-string friction (more is better), and string-string friction (less is better) Turns out, low inter string friction, is a much more important factor than ball "bite"

QUOTE 1: "Until recently, the prevailing theory regarding string stiffness and spin has been that the firmness and lateral rigidity of a stiffer string will create more ball-to-string friction due to more squashing and embedding, resulting in more spin. It is true that friction accounts for most of the spin produced by the stringbed, but it does not account for most of the difference in spin between stringbeds. Recent research suggests that lateral main string movement is the most important factor determining this difference." -- Crawford Lindsey, March 14, 2011

QUOTE 2 : "Recent experiments (Spin and Material, Spin and String Movement, Spin and String Pattern and String Snap-Back and Spin) have also demonstrated that sideways motion of the main strings during contact with the ball actually contributes to increasing spin. This sideways movement exerts a torque on the ball when it snaps back into position, thus causing topspin. Polyesters have been shown to add about 20% more spin than nylons. Polyesters can differ up to about 15% from each other in spin production while nylons might vary by 20% from each other. And the difference between the spiniest polyester and stickiest nylon is almost 50%. Virtually all this difference is attributable to the amount of torque supplied by the sideways movement and snap back of the main strings.The role of ball-string friction in this process is that it influences both the amount of lateral string movement and the torque the snap-back exerts on the ball (though the magnitude of its contribution is yet to be ascertained by experiment). It is here that ball-string friction contributes to the difference in spin performance between string models, but only if the strings move. Otherwise, ball-string friction produces about the same spin for every string. And whether the strings move or not depends on the static and sliding friction between strings. " -- Crawford Lindsey, August, 2011, Static Friction and Spin

QUOTE 3 : Summary Observations:
• All the polyesters had more spin than any of the nylons (a gut snuck in above some polys however).
• The average polyester spin compared to the average nylon is +20.2%.
• The difference in spin between the highest and lowest poly is +15.9%.
• The difference in spin between the highest and lowest nylon is +26.8%.
• The difference in spin between the highest string and the lowest string is +49.3%.
-- Crawford Lindsey, String movement and Spin

Links: Static Friction And Spin , How String-to-Ball Friction Affects Spin , String Snap Back and Spin , Which Strings Generate The Most Spin?

2c. Getting the string to grip the ball is not a problem!. (See Video Below) The lab testing was performed by the International Tennis Federation. I've seen many slow motion impact vids. This one is the most dramatic. The others show the ball smashing to about to about 1/2 original size.



Video Link Here:
http://www.youtube.com/watch?v=pufedQgGYzg&feature=plcp

[..]

Issue 3: Dwell Time And Control:

3A. Some players opine that longer dwell times increase control. Not only is there no experimental evidence for this, it runs counter to the age old truism accepted by both academics and players ... "string tight for control, loose for power".

- Jack

[pvaudio]

Excellent post, ChicagoJack. I think, however, the problem was simply a matter of wording. When people talk about dwell time and pocketing, they're almost always talking about the feeling that the ball is sinking into the stringbed. The only point I was trying to make is that the difference in stringbed contact time between strings is absolutely minimal. When you search around for dwell time, you get results with people saying strings have great dwell time or pocketing. That's a feeling, and as shown in your measured results, the difference between strings is only on the order of milliseconds, so there is no way you're feeling an appreciable increase in stringbed contact. That's where the thread got off on the wrong track, I never said that the time that the ball spends on the stringbed isn't measureable. If it wasn't, then there would be no way that I would know just how short of a time it's there

[ChicagoJack]

PVAudio - Yeah cool man, totally understand BTW agreed with most of all your comments within. It's really hard to talk about this stuff in a productive way when the same terms mean so many different things to different people.

Yes, I am an admitted data nerd. Nothing soothes my soul more than looking at nicely organized columns of digits, and attempting to understand the secrets held therein. On the other hand, I am a tennis player too. I get it. I feel what I feel. One of my frames is strung with Dunlop Black Widow 18 at 54lbs. When I'm returning a big server who can dish out lots of pace and rpms, it just seems like the ball stays in the stringbed forever, first sliding, then unwinding whilst I undo all the spin of the incoming ball, and attempt to reverse it with my own top spin and send it back. I can certainly understand why peeps search for a way to describe this sensation which seems to last forever and settle on dwell time.

What is actually happening is most of the impact sensation you feel (especially when you contact outside the sweet spot, and especially near the tip) is the residual frame vibration that occurs well after the ball exits the string bed. I could explain more about that, but that last post wore me out. Another day perhaps.

-Jack

[fortun8son]

Agreeing on the definition of terms is essential to a rational discussion.
If you don't, you're arguing at cross purposes.
I think that's what happened here.
Tennis is not a science, no matter how much some of us wish it were.

[corbind]

Great work Jack. You're a man after my own heart!

[akamc]

ChicagoJack, that is a very interesting video clip! It certainly looks more extreme than my mental picture of a typical shot and would change how I visualize ball-string interaction, except that I wonder how fast the ball was traveling and how the racket was anchored. Also, isn't that a pressureless Tretorn Micro-X ball which may not react like a normal ball?
Most slow-mo clips of pros hitting do not appear to show so much ball deformation, but they are also not so detailed.

[tlm]

Originally Posted by pvaudio

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.

If a more elastic string that slides more is better for spin then why does kevlar which is very stiff and non elastic put so much spin on the ball? When I go from kevlar to a all poly set up it seem like I get just as much spin if not more from the kevlar, but more power from the poly.

[pvaudio]

Originally Posted by tlm

If a more elastic string that slides more is better for spin then why does kevlar which is very stiff and non elastic put so much spin on the ball?

That was exactly my point, it's a conundrum. Greater stiffness yields higher spin potential, but greater elasticity also yields higher spin potential. My theory, which is my reasoning alone, is that gut yields good spin because it is so elastic that it's able to overcome a lot of the string-string friction. Kevlar, which has extraordinary ball-string friction will also yield good spin potential. Whether this is true or not, I have no idea, but I DO know that it's because poly can combine the best attributes of both of these string types and meet in the middle that it's far superior than either with regards to spin potential.

[tlm]

Originally Posted by pvaudio

That was exactly my point, it's a conundrum. Greater stiffness yields higher spin potential, but greater elasticity also yields higher spin potential. My theory, which is my reasoning alone, is that gut yields good spin because it is so elastic that it's able to overcome a lot of the string-string friction. Kevlar, which has extraordinary ball-string friction will also yield good spin potential. Whether this is true or not, I have no idea, but I DO know that it's because poly can combine the best attributes of both of these string types and meet in the middle that it's far superior than either with regards to spin potential.

That makes some sense, but I am not so sure that poly can really exceed kevlar in spin potential let alone be far superior. I feel that because poly puts more power on the ball that many players will see a better hop off the court because of the polys power not spin, so then many would think they are getting more spin but actually it is more power.

If we are talking about just spin I think that kevlar actually produces more spin than poly.

[pvaudio]

Actually, thinking about it more, I would bet Kevlar works because it is highly resilient. I know, more boring terms, but resilience is the ability for something absorb energy when it is deformed elastically. It is the ratio of yield strength squared to young's modulus. Not going to get into that, BUT, the yield strengh of Kevlar is extremely high, and if it's a squared term, that could negate the high Young's modulus if it's a lower order. This is pure speculation on my part.

http://en.wikipedia.org/wiki/Resilience

[pvaudio]

Originally Posted by tlm

That makes some sense, but I am not so sure that poly can really exceed kevlar in spin potential let alone be far superior. I feel that because poly puts more power on the ball that many players will see a better hop off the court because of the polys power not spin, so then many would think they are getting more spin but actually it is more power.

If we are talking about just spin I think that kevlar actually produces more spin than poly.

But it doesn't. TWU has tested strings extensively and poly is always top of the charts across materials.

[UCSF2012]

So what's the final verdict? "Does increased ball pocketing and thus dwell time equal more spin potential?"

[tlm]

Originally Posted by pvaudio

But it doesn't. TWU has tested strings extensively and poly is always top of the charts across materials.

Well maybe so, but are we talking about tests with rackets hooked to machines and pressure-less balls? Some of these lab tests are not the same as players hitting the ball.

[pvaudio]

Originally Posted by tlm

Well maybe so, but are we talking about tests with rackets hooked to machines and pressure-less balls? Some of these lab tests are not the same as players hitting the ball.

Well, just as one example, Agassi played with Kevlar for much of his career. The first time he tried poly, he said, in my paraphrasing, that the spin was akin to cheating.

[tlm]

Originally Posted by pvaudio

Well, just as one example, Agassi played with Kevlar for much of his career. The first time he tried poly, he said, in my paraphrasing, that the spin was akin to cheating.

I remember him saying that poly was like cheating but I don't remember him saying that the spin was the main factor. The comparison of the pro players using poly and us amateurs is not very good to me. These guys use a fresh string job every half hour or so.

And I will say that I love fresh poly, it is hard to beat. But even after an hour or so I can tell a difference in the playability, spin and control of poly, let alone a few days. But with the kevlar main and poly cross I am using right now the consistency is way better than a full poly job, no comparison in my opinion.

[pvaudio]

Fair enough. Regardless, given how spin-reliant today's game is, I don't think it's coincidence that poly is the dominant string material whether in hybrid or in full. Now if the argument is about rec players vs. the pros, that's missing the point entirely because this is about spin potential. If you can generate the RHS required, the poly wins. I don't think it's coincidence that Kevlar has more or less become obsolete as a string material. And actually, Kevlar has the highest rate of tension loss of all string materials.

[ChicagoJack]

Originally Posted by akamc

ChicagoJack, that is a very interesting video clip! It certainly looks more extreme than my mental picture of a typical shot and would change how I visualize ball-string interaction, except that I wonder how fast the ball was traveling and how the racket was anchored. Also, isn't that a pressureless Tretorn Micro-X ball which may not react like a normal ball? Most slow-mo clips of pros hitting do not appear to show so much ball deformation, but they are also not so detailed.

Hi akamc -

Yeah I know, pretty dramatic stuff. Of all the slow mo vids and photos I've seen, that one shows the most extreme ball deformation. Ball compression to about 45% original size is much more typical. I'm curious about the ball velocity, and impact conditions as well. Regarding the Tretorn Micro X balls, they aren't the limp noodles that the phrase "pressureless" might imply. Rather than being gas injected like typical balls, that lose pressure every second of every minute, they are filled with millions of balloon like microcells, that don't leak. While you might find the Tretorns sanctioned for use once in a blue moon for tournament play, they are mainly used for ball machines, because they stay playable for a very long time. Based on the user feedback right here at TW, they play a bit like stiff, extra duty balls. Pure conjecture on my part, but I'm guessing that the ITF chose these balls for their tests, because they needed a tough felt to stand up to the machines that fire the balls, and they needed a ball that offered a solution to the problem of regular balls losing pressure so quickly.
http://www.tennis-warehouse.com/feedback-tretpress.html
http://www.tennis-warehouse.com/Tret...TRETPRESS.html

-Jack

[..] ......................

Originally Posted by UCSF2012

So what's the final verdict? "Does increased ball pocketing and thus dwell time equal more spin potential?"

Hi USCF2012 -

Yeah cool, sorry I cant give you the short answer you are looking for. That's actually like four separate questions all tangled up into one question. Some basic distinctions are needed first.

1. Although you have verbalized it as such, increased ball pocketing and increased dwell time are not always synonymous, in fact they are often inversely related. See my post #41, Para 1C for greater detail.

2. Ball pocketing, or more properly said, string bed deflection, is defined as the amount of deflection perpendicular to the string plane. This is not associated with spin enhancement. See my post #41 2A for greater detail.

3. Spin enhancement has been shown in recent years to be a product of two factors, ball-string friction and inter-string friction. Low inter-string friction promotes slide and snap back, parallel to the string plane. This happens while the string bed is deflecting/pocketing, but the deflection backwards is not what generates the additional spin. The additional spin is generated by the string brushing up the back of the ball in the vertical plane (on a groundstroke). See links in Post #41 2B for greater detail.

-Jack

[..] ......................

Originally Posted by tlm

If we are talking about just spin I think that kevlar actually produces more spin than poly.

Originally Posted by tlm

Well maybe so, but are we talking about tests with rackets hooked to machines and pressure-less balls? Some of these lab tests are not the same as players hitting the ball.

Hi Tlm

I don't ever argue what people feel/observe on the court. However, with regards to Kevlar offering more spin enhancement than poly, I invite you to consider that:

1. The 3 most credible racquet technicians on the planet, ie. the Holy Trinity of Roman Prokes, Nate Ferguson, and Warren Bosworth, all say otherwise.

2. The select few who study, and publish racquet physics for a living... Brody, Cross, Lindsey, all say otherwise.

3. Then there is the pro tour. Not many supporters there. As Pv Audio has noted, Agassi was the last Kevlar user of any note.

4. I used Kevlar myself for a few years circa 2001-2002. I was too was pretty convinced at the time I'd found the ultimate spin machine. I think I understand now why I thought that. There is a very plausible explanation to why you feel what you feel with Kevlar, why you might perceive it to be more spin friendly than poly. It isn't texture, or dwell, or increased ball grip. Perhaps it's just that it's very low powered. It's very stiff, in fact, 2-3 times stiffer that the stiffest poly. This just means you have less fear of hitting long. You swing faster when you don't fear hitting long. Swinging faster creates more spin. Your stroke has changed because of the string, but the additional spin is coming from your stroke, not the string itself. In lab experiments, they have proven conclusively that irrespective of player technique, certain strings produce more spin than others. That's the central issue at hand. Kevlar is no where near the top of that list. Pretty consistently, it's slippery textured poly as a full bed, or Gut/Poly that tops the spin charts.

5. What's ironic, is that for years following the The University Of Sheffield testing done by Goodwill and Haake circa 2004, the entire racquet physics community (excepting our very own TravlerAJM, who knew better) came to the conclusion that strings don't make any difference at all with regards to spin. That conclusion was 180 degrees opposite from what we were all experiencing on the court. More recent testing has only validated what players have known all along, that strings do make a difference with regards to spin. Even though we now have lab testing which validates the player experience, players are still skeptical of the dudes in the white lab coats, and perhaps rightly so.

-Jack

[..] ......................

Originally Posted by corbind

Great work Jack. You're a man after my own heart!

Hi Corbind

I'm no braniac, I can barely add and subtract. Just know where to find the answers, just a dumb jock who prefers reading racquet physics to prescription sleep aids, and it works really well for that purpose. Haha.

-Jack

[tlm]

Originally Posted by ChicagoJack

Hi akamc -

Yeah I know, pretty dramatic stuff. Of all the slow mo vids and photos I've seen, that one shows the most extreme ball deformation. Ball compression to about 45% original size is much more typical. I'm curious about the ball velocity, and impact conditions as well. Regarding the Tretorn Micro X balls, they aren't the limp noodles that the phrase "pressureless" might imply. Rather than being gas injected like typical balls, that lose pressure every second of every minute, they are filled with millions of balloon like microcells, that don't leak. While you might find the Tretorns sanctioned for use once in a blue moon for tournament play, they are mainly used for ball machines, because they stay playable for a very long time. Based on the user feedback right here at TW, they play a bit like stiff, extra duty balls. Pure conjecture on my part, but I'm guessing that the ITF chose these balls for their tests, because they needed a tough felt to stand up to the machines that fire the balls, and they needed a ball that offered a solution to the problem of regular balls losing pressure so quickly.
http://www.tennis-warehouse.com/feedback-tretpress.html
http://www.tennis-warehouse.com/Tret...TRETPRESS.html

-Jack

[..] ......................


Hi USCF2012 -

Yeah cool, sorry I cant give you the short answer you are looking for. That's actually like four separate questions all tangled up into one question. Some basic distinctions are needed first.

1. Although you have verbalized it as such, increased ball pocketing and increased dwell time are not always synonymous, in fact they are often inversely related. See my post #41, Para 1C for greater detail.

2. Ball pocketing, or more properly said, string bed deflection, is defined as the amount of deflection perpendicular to the string plane. This is not associated with spin enhancement. See my post #41 2A for greater detail.

3. Spin enhancement has been shown in recent years to be a product of two factors, ball-string friction and inter-string friction. Low inter-string friction promotes slide and snap back, parallel to the string plane. This happens while the string bed is deflecting/pocketing, but the deflection backwards is not what generates the additional spin. The additional spin is generated by the string brushing up the back of the ball in the vertical plane (on a groundstroke). See links in Post #41 2B for greater detail.

-Jack

[..] ......................





Hi Tlm

I don't ever argue what people feel/observe on the court. However, with regards to Kevlar offering more spin enhancement than poly, I invite you to consider that:

1. The 3 most credible racquet technicians on the planet, ie. the Holy Trinity of Jay, Nate, and Warren, all say otherwise.

2. The select few who study, and publish racquet physics for a living... Brody, Cross, Lindsey, all say otherwise.

3. Then there is the pro tour. Not many supporters there. As Pv Audio has noted, Agassi was the last Kevlar user of any note.

4. I used Kevlar myself for a few years circa 2001-2002. I was too was pretty convinced at the time I'd found the ultimate spin machine. I think I understand now why I thought that. There is a very plausible explanation to why you feel what you feel with Kevlar, why you might perceive it to be more spin friendly than poly. It isn't texture, or dwell, or increased ball grip. Perhaps it's just that it's very low powered. It's very stiff, in fact, 2-3 times stiffer that the stiffest poly. This just means you have less fear of hitting long. You swing faster when you don't fear hitting long. Swinging faster creates more spin. Your stroke has changed because of the string, but the additional spin is coming from your stroke, not the string itself. In lab experiments, they have proven conclusively that irrespective of player technique, certain strings produce more spin than others. That's the central issue at hand. Kevlar is no where near the top of that list. Pretty consistently, it's slippery textured poly as a full bed, or Gut/Poly that tops the spin charts.

5. What's ironic, is that for years following the The University Of Sheffield testing done by Goodwill and Hawke circa 2004, the entire racquet physics community (excepting our very own TravlerAJM, who knew better) came to the conclusion that strings don't make any difference at all with regards to spin. That conclusion was 180 degrees opposite from what we were all experiencing on the court. More recent testing has only validated what players have known all along, that strings do make a difference with regards to spin. Even though we now have lab testing which validates the player experience, players are still skeptical of the dudes in the white lab coats, and perhaps rightly so.

-Jack

[..] ......................


Hi Corbind

I'm no braniac, I can barely add and subtract. Just know where to find the answers, just a dumb jock who prefers reading racquet physics to prescription sleep aids, and it works really well for that purpose. Haha.

-Jack

Okay Jack fair enough, I just get hooked on the great spin I get with a kevlar main and poly cross. But more than that this set up plays so much more consistent than a full poly job does.

I love poly when it is fresh, but it come nowhere near kevlar when it comes to maintaining pinpoint control with its built in restricted flight even after a few hours of use. I hit a high trajectory with a lot of top spin and when the poly starts to lose some tension I have a harder time with shots going long.

And even though I know kevlar loses tension quickly it does not lose its control anywhere near as quick as poly does. I am still experimenting with different poly set ups and hoping to find one that works. Because I would like to get away from the kevlar its stiffness can be hard on the arm. But like I mentioned its unmatched control and pinpoint accuracy is addicting.

By the way what club do you play out of, I play in the suburbs out of Park Forest and Homewood.
TLM

[jmnk]

Originally Posted by ChicagoJack

[What's ironic, is that for years following the The University Of Sheffield testing done by Goodwill and Hawke circa 2004, the entire racquet physics community (excepting our very own TravlerAJM, who knew better) came to the conclusion that strings don't make any difference at all with regards to spin. That conclusion was 180 degrees opposite from what we were all experiencing on the court. More recent testing has only validated what players have known all along, that strings do make a difference with regards to spin. Even though we now have lab testing which validates the player experience, players are still skeptical of the dudes in the white lab coats, and perhaps rightly so.

Could you provide a link/reference to those more recent testing?

[ChicagoJack]

Originally Posted by jmnk

Could you provide a link/reference to those more recent testing?

Hi Jmnk - Sure, no problemo. See my links in post #41 section 2B. That's a good start. -Jack