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View Full Version : Would this spin-enhancing technology be legal?


jmsx521
12-26-2006, 06:26 AM
If there was a spray that sprays a combination of strong glue and tiny sand-paper-size grains… would it be legal to spray it on the strings? Suppose you have strings that are heavily textured, like sand-paper, and you have other strings with smooth surface, that are not textured, wouldn’t the textured strings grip the ball better… just like sand-paper does?

theace21
12-26-2006, 07:19 AM
If it worked and imparted massive spin it would be made illegal. Way back in the 70's, several players tried this racket with "spaghetti string". Nastase beat Vilas to end his winning streak with that racket. It was soon made illegal...

Special strings might help, but spin is really a matter of racket head speed.

mctennis
12-26-2006, 07:19 AM
Nope, not allowed according to Tennis rules.

ChicagoJack
12-26-2006, 07:23 AM
Hello jmsx 521 -

I know you will not believe me, but the texture of the string makes zero difference when it comes to spin production. The world is chock full of players who share your quest for the ultimate spin string. Sorry to burst your bubble but it does not exist.

On String Material, Texture, And Spin: replies #7, #13 #18
http://tt.tennis-warehouse.com/showthread.php?t=109039

On String Tension And Spin:
http://tt.tennis-warehouse.com/showthread.php?t=106870

-Jack

ChicagoJack
12-26-2006, 07:29 AM
Spaghetti string caused crazy spin, but not because friction. It was because the strings moved freely against each other. Yes, also agreed than spin is about racquet head speed, but maximum spin is also produced at contact angles approaching 40 degrees. So if you want more spin, swing faster or alter stoke path/racquet face angle. Those are the only two things on the menu. Do one, or do both. Both are technique alterations.

Both technique alterations might be helped by string changes in tension or stiffnes. High tension or stiff string might help you swing fast and keep the ball from sailing long. Low tension string might prompt the player, knowingly, or unknowingly to tilt racquet face closer to 40 degrees. But when you look at the ball/string interaction alone, string changes make suprisingly little, or no difference at all with regards to rebound spin.

The moral of the story is - start thinking in terms of equipment that enhances these 2 crucial elements of your stroke with regards to spin. That is the right part of the pond to fish in. That is where the trail for the ultimate spin string ends.

http://tt.tennis-warehouse.com/showthread.php?t=106870
( see reply # 28 on spaghetti stringing )

-Best regards
Jack

jmsx521
12-26-2006, 07:47 AM
ChicagoJack, yes, some impressive information you are giving.

ChicagoJack
12-26-2006, 07:56 AM
ChicagoJack, yes, some impressive information you are giving.


Hi jmsx521 ;)

Thanks for that. I've come full circle on this stuff. I played for two years with a kevlar string, that had a very sharp gear profile, in a very low powered, flexy frame. I get where you are coming from, because I was on that quest too. There is money to be made by marketing gimmick string. Maybe in 5-10 years everybody will understand the true nature of string, and what I am posting will not be so counter-inuitive.

Best regards to you, take care
-Jack

Ripper
12-26-2006, 12:10 PM
If there was a spray that sprays a combination of strong glue and tiny sand-paper-size grains… would it be legal to spray it on the strings? Suppose you have strings that are heavily textured, like sand-paper, and you have other strings with smooth surface, that are not textured, wouldn’t the textured strings grip the ball better… just like sand-paper does?

LaserFibre has a string that, as far as I understand, is similar to what you described. Certain textured strings may help a bit with spin, in certain situations. Personally, my biggest 'beef' with these types of strings is that the sharp texture wears off, way before they lose their playability. All of them. Even the harder textured polys wear out. So, unless you have a stringing machine and lots of free time, just avoid them.

Kevo
12-26-2006, 08:01 PM
Ripper is right. All of the textured strings I've tried don't last very long. The do seem to work for a little while though. Some of these are clearly gimmicks however. Luxilon Alu Rough for instance. It's a nice playing string, but it's not really rough at all. I didn't notice any difference in spin between it and regular smooth poly. I think higher tension or a stiffer string will encourage more spin than a string change. That will take pop off your shots and make you want to swing faster for more power. The faster racquet speed will create more spin.

The longest lasting textured string I tried was Klip Dura if I remember correctly. It has kind of a woven surface and it seemed to last a long time. That string pulled lots of felt off the balls, so if you don't want to spend more on tennis balls, you may not want to try that string.

Steve Huff
12-26-2006, 08:33 PM
Cjack is right about the spaghetti strings not enhancing spin, but giving odd, often unpredictable spin. They were designed to actually reverse the spin, which it would sometimes.

Textured strings CAN give more spin. I think it was the USTA study that showed thick, textured strings at low tensions added spin. But, stroke mechanics contributes far more to the spin production than any string.

ChicagoJack
12-26-2006, 08:48 PM
Cjack is right about the spaghetti strings not enhancing spin, but giving odd, often unpredictable spin. They were designed to actually reverse the spin, which it would sometimes.

Textured strings CAN give more spin. I think it was the USTA study that showed thick, textured strings at low tensions added spin. But, stroke mechanics contributes far more to the spin production than any string.


Hi Steve - ;)

Jay Schweid made a comment in tennis magazine that lower tension, and thicker strings, cause more spin. The USRSA got a ton of emails. The comment caused quite a controversy. In October 2003 Crawford Lindsey, RSI/USRSA, wrote an article to quell the angry crowd with pitchforks at his door. The article de-bunked the statement, by way of referencing the most extensive lab experiments on the subject. There never was a USTA experiment on this to the best of my knowledge. If you follow my links, you'll see I've posted the results of the sheffield experiment Lindsey references, that did address this question.

I'm not saying you are wrong, or Jay is wrong. But there is a mountain of evidence suggesting conclusively that in regards to ball/string interactions - texture, thickness, spacing, and tension have zero effect on spin. What does change is rebound angle and velocity. Both these thing can cause the player to alter his stroke in a way that produces more spin. The string might change the stroke, the stroke change might cause more spin. This is all explained in greater detail in my links above.

Best regards to you
-Jack

VGP
12-26-2006, 09:38 PM
Legal or not, I think that would be a quick way to break your strings.

You might as well be playing tennis on the beach.......no offense to Beachtennis!

travlerajm
12-26-2006, 09:58 PM
If a change in string properties changes the rebound angle when the racquet is clamped in a lab, that means the strings are grabbing the ball more. Thus the change results in more spin. I think Jack is confusing the issue.

If you want more spin, use lower tension.

ChicagoJack
12-26-2006, 10:52 PM
If a change in string properties changes the rebound angle when the racquet is clamped in a lab, that means the strings are grabbing the ball more. Thus the change results in more spin. I think Jack is confusing the issue.

If you want more spin, use lower tension.

Incredible. We had this debate allready. You didnt respond to my last quotes which illustrated how you continually perpeuate a falsehood regarding the intent, technique, and conclusions of the sheffield study. If you want to disagree with me, or the intent of the research, you are free to do so. But I am not confused. The intent, and conclusions of the research is not what you say it is.

In 2005 Dr. Goodwil wrote a recap of his research for RSI magazine. In this article [2] he was able to offer an explanation as to why the world is full of players that are absolutely convinced that changes to string tension produce changes in spin. His explanation is the same as yours. An adjustment in technique has caused the spin. You say lower tensions nudge the player to tilt the racquet face. Goodwil suggests higher tensions can help the player swing faster and still keep the ball in the court. Both of these statements have merit, and both are by-products spun off from the 2002 research. Neither statement is wrong, but perhaps is one more "right" than the other.

Consider that with low tension, the same stroke would only produce a higher rebound trajectory and increased velocity. If the player makes no adjustment the ball just sails a little higher, faster, or deeper. At high tension, the same player with the same exact swing gets a better speed to spin ratio. Although the spin is not greater at higher tensions, the ball speed will be lower, so the ratio of spin to speed will be greater. The ball will then appear to land shorter in the court at slightly steeper angles and to bounce higher, in reality just consequences of less velocity. But you can't have it both ways. If you want to open the can of worms called ball/player/string interactions, then you've got to let out ALL the worms. It's intellectually dishonest to continually suggest yours the only correct conclusion.

For the tension issue: please see reply 56
http://tt.tennis-warehouse.com/showthread.php?t=106870&page=3



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



..... that means the strings are grabbing the ball more. Thus the change results in more spin. I think Jack is confusing the issue. If you want more spin, use lower tension.
This statement is patently false. More grab does not equal more spin:

QUOTE [1] SPIN: It is an experimentally observed fact that the ball spin off the strings does not depend upon whether the strings are thin or thick, rough or smooth, soft, stiff or slippery:

"Biting and rolling are similar for a tennis ball. If a ball rolls during the bounce, then the rebound spin and speed, do not depend on the coefficient of friction of the surface, but they do depend on the angle of incidence. In essence, this explains the experimentally observed fact that the ball spin off the strings does not depend upon whether the strings are thin or thick, rough or smooth, soft or stiff. These differences would be important if the ball slides along the string throughout the whole bounce period, but this would require the ball to be incident on the strings at an angle less than 40 degrees to the string plane. More commonly, the ball is incident closer to a right angle to the string plane, in which case the ball will bite before it bounces off the strings." [1]

[1] The Physics and Technology of Tennis
Howard Brody, Crawford Lindsey, Rod Cross, Published 2002, USRSA
Chapter 41, Ball Spin and Bounce Off a Racquet: Page 371, Paragraph 3
http://www.tennis-warehouse.com/descpage-PHYSICS.html

Note: There is so much info packed into this one para, it's difficult to understand on the first read thru. The basic idea is that the friction or "grab" of the stringbed is a non issue because at the angles of contact in the typical tennis stroke the ball is never in danger of sliding through out the entire bounce. Sliding thru out the whole bounce is not uncommon with bounces off the court, but is virtually imposible off the stringbed. The ball grabs everytime 100%. There is no such thing as more grab or less grab. There is only bite sooner or bite later, but in both cases, the end result stays the same with regard to spin. The ball WILL start to slide through out the whole bounce phase at angles past 40 degrees. Most tennis players are incapable of hitting at these angles, but many table tennis players do. Grabbing the ball is a factor in that sport, which is why the reversed pimple, super tach rubber has revolutionized that sport. With tennis, the impact forces alone are enough to make the ball bite everytime. In fact, the ball squashes to almost half its original size. Biting is not a problem in tennis. It happens with every string, at every tension, everytime. Quote 2 is saying the same thing, and the attached link gives the whole issue a much more detailed look.


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



QUOTE [2] SPIN: Ball spin is not dependent on string tension or string type:

" Fortunately, the spin generated for a typical ball-racquet impact can easily be measured. This has been done at the University of Sheffield in England, and the results showed that the spin on the ball is not dependent on string tension or string type. In that testing it was concluded that all stringbeds are sufficiently "rough" to achieve maximum spin for the given shot. Therefore, even if thin, sticky, and tight strings were used in an attempt to increase stringbed "roughness," there would be no actual increase in rebound spin."[2]

[2] Does Higher String Tension Give More Control and Spin ?
By Dr. Simon Goodwill, University of Sheffield, UK.
Published: January 2005: RSI Magazine, A Publicaton Of The United States Racquet Stringers Association
http://www.racquetsportsindustry.com/issues/200501/200501tension.html

-Jack

travlerajm
12-26-2006, 11:28 PM
I didn't say you were confused. But if you keep telling people that tension doesn't make a difference for spin potential, you are misleading them and causing confusion.

ChicagoJack
12-26-2006, 11:36 PM
I didn't say you were confused. But if you keep telling people that tension doesn't make a difference for spin potential, you are misleading them and causing confusion.

I'm not misleading anybody, I'm telling the whole story. You are telling 1/2 the story in a very misleading way:

Consider that with low tension, the same stroke would only produce a higher rebound trajectory and increased velocity. If the player makes no adjustment the ball just sails a little higher, faster, or deeper. At high tension, the same player with the same exact swing gets a better speed to spin ratio. Although the spin is not greater at higher tensions, the ball speed will be lower, so the ratio of spin to speed will be greater. The ball will then appear to land shorter in the court at slightly steeper angles and to bounce higher, in reality just consequences of less velocity. High tension does not require a stroke adjustment for an increase in the speed to spin ratio. Low tensions DO require a stroke adjustment for greater spin. But you can't have it both ways. The sheffield study was about ball/string interactions only. If you want to open the can of worms called ball/player/string interactions, then you've got to let out ALL the worms. It's intellectually dishonest to continually suggest yours the only correct conclusion. It's only one of two, and the weaker one I might add.

Here is a handy and very accurate equation to estimate your swingweight simply by measuring the mass and balance of your racquet accurately. It will generally be accurate to within +/-10 kg-cm^2. The uncertainty is due to the unknown degree of polarization of your racquet. Be sure to measure the mass to nearest gram and balance accurately to nearest half millimeter!

Here it is:
SW at 10 cm from the butt =
1.5MR^2 + 20M(5 - R)
M = mass in kg
R = balance in cm

You may notice that this is simply an application of the parallel axis theorem - i.e., the swingweight about the butt end is approximately 1.5MR^2.

You expect folks to understand the above formula, but fear they might not understand the meaning of big words such as "friction" ? If you came here to educate, then educate.

You are using the phrase "spin potential" in a very crafty way. It is the way a politician goes right up to the line between a truth and falsehood and puts one foot on each side. To do this with such precision tells me you know exactly where the truth is, but you are speaking what people want to hear instead.

OY.

-Jack

travlerajm
12-27-2006, 12:05 AM
Jack,
Have you actually stopped to think about Goodwill's ball speed to ball spin ratio you keep talking about? Yes it exists. But if you do the math, you quickly realize that the effect is negligible. If you bother to do the math and change the frame of reference to the ball instead of the racquet (which Goodwill didn't bother to do), it's obvious that the effect of rebound angle is an order of magnitude greater then the ball speed to ball spin ratio effect.

Goodwill also didn't bother to do any checking on his "anecdotal evidence" that higher tensions give more spin. I'm guessing that he just pulled it off of Wilmot McCutchen's racquetresearch.com site, which still contains incorrect information on this subject, even though Wilmot has recently made some corrections in repsonse to other Talk Tennis posters' comments.

If Goodwill had bothered to interview high level players, his anecdotal evidence would have been the opposite of what he started with, which may have influenced his conclusions.

ChicagoJack
12-27-2006, 12:24 AM
Jack,
Have you actually stopped to think about Goodwill's ball speed to ball spin ratio you keep talking about? Yes it exists. But if you do the math, you quickly realize that the effect is negligible. If you bother to do the math and change the frame of reference to the ball instead of the racquet (which Goodwill didn't bother to do), it's obvious that the effect of rebound angle is an order of magnitude greater then the ball speed to ball spin ratio effect.

Goodwill also didn't bother to do any checking on his "anecdotal evidence" that higher tensions give more spin. I'm guessing that he just pulled it off of Wilmot McCutchen's racquetresearch.com site, which still contains incorrect information on this subject, even though Wilmot has recently made some corrections in repsonse to other Talk Tennis posters' comments.

If Goodwill had bothered to interview high level players, his anecdotal evidence would have been the opposite of what he started with, which may have influenced his conclusions.

Pont 1 : You are now shifting the conversation to an area where you feel comfortable debating. Wilmot McCutchen, and his web site has nothing to do with this. This consistent browbeating of your peers, doesnt look good on you.

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

Point 2 : I've done the math you mention. I've allways agreed with you that lower tensions create higher rebound trajectory. You keep bringing this up as if it were a big secret. This is well known, and not a contentious point with anybody who has studied the issue. I agree ( sort of ) that the change in rebound angle is greater than the change you'd get with the high tension increased rpm ratio. The point you are making here though is slim on substance for 2 reasons:

A - This is an apples to oranges comparison, i.e spin to rebound angle.

B - A higher rebound trajectory does not mean more spin. period. end of story. A higher rebound angle means what it is. If the player makes no adjustment, the ball sails a little higher, deeper, faster.

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

Point 3 : "Lower tensions cause greater spin" This statment is patently false. It is an experimentally observed fact that this statement is false. I have provided 8 references in a previous thread to support this fact and could provide you with 100 more. The only thing preventing me from doing so is respect for the copyright of the authors, the rules of this board, and my own sense of personal integrity.
The 8 Refs begin on reply #28:
http://tt.tennis-warehouse.com/showthread.php?p=1113669#post1113669

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

Point 4 : "The conclusion of the Sheffield study is flawed, they misinterpreted their own data and results, their data proved lower tensions produce more spin" This implication is patently false, because the statement is based on a false representation of the the purpose, methods, and conclusions of the study. I have submitted several sections of text from the actual study itself that very clearly contradicts your falsehood.
See Reply #56:
http://tt.tennis-warehouse.com/showthread.php?t=106870&page=3

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

Point 5 : "Lower tension produces greater spin potential" This statement has a solid element of truth to it, but is misleading by way of gross over simplification of a complex issue. If you want to expand the topic from the narrowly focused world of ball/string interactions, to the can of worms called ball/string/player interactions, then you have to let out all the worms. What is missing from this statement is two things:

A - Lower tensions might prompt a stroke adjustment, that is, a downward tilt of the racquet face. It is this downward tilt of the racquet face that produces extra spin.

B - Higher tensions can prompt a stroke adjustment as well, that is, increased swing speed to make up for the reduced depth.

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

Point 6 : The effect of tilting the racquet face even a few degrees can alter spin dramatically. The effect you mention does exist. Rod Cross wrote a very good article explaining this phenomena in 2005, entitled "The inch that changed tennis forever", which I first posted here, in the summer of 06. This is also harmonious with the quote I provided: "Maximum spin is achieved at angles approaching 40 degrees". If lower tensions help you do this, then this is beneficial. On this much we agree, but I am not splitting hairs. The notion that the players stroke adjustment produces the spin is an important distinction, one well worth the effort of explaining. One which you continually leave out.

I prefer to give people all the information required for them to make and informed decision based on skill level and personal preferences. For example: A player who chooses to swing faster to create spin might see an increase in mishits. Hitting the ball with a more closed racquet face, might require a grip change. Both of these stroke adjustments may not be easy for players to make. Both deserve a mention. You seem to be intrested in boiling down the facts of a very complex issue so much that it scarcely resembles the original truth. Trying to give people the full and complete truth in a way that is easy to understand, is no easy task. That is what I am attempting.

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

Point 7 : Just because you are right does not mean somebody else is wrong. Every Philosophy major knows this, and many Physics Phd's have difficulty living with this concept. High tension can promote faster swings. Low tension can produce steeper angles of contact. Both these things are true. It is counter-intuitive to the human species that two seemingly opposing ideas on the same topic can be true. All the more reason to stress the point at every opportunity.

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

If you are determined to have the last word on this, then have it. You win by virtue of stubborn persistance, not substance.

-Jack

travlerajm
12-27-2006, 12:34 AM
I do not think that mentioning that there are inaccuracies on a well-respected but controversial site like Wilmot's constitutes browbeating.

My goal here is to help people get the most out of their racquets. If someone comes to me and wants to get more spin potential out of his racquet, then I will tell him how to do it. It's as simple as that.

If there is misleading information out there, I'm going to say so and why.

uk_skippy
12-27-2006, 03:04 AM
try this site. Hopefully it works as its Japanese but translated thru google.

http://translate.google.com/translate?hl=en&sl=ja&u=http://tennis365.net/asp/ItemFile/10003301.html&sa=X&oi=translate&resnum=3&ct=result&prev=/search%3Fq%3Dmira%2Bfit%26hl%3Den%26lr%3D%26rls%3D com.microsoft:en-gb

If it doesn't work, type mira fit into google and go to the tennis365 site result.

I was given a sample while @ Wimbledon, but havent really used it as I'm not a mega-topspinner, or a player trying to achieve that

Regards

Paul

thomas martinez
12-27-2006, 04:08 AM
Chicago Jack, do yourself a favour and don't try to argue with that guy. He'll not see his points are wrong and such. He'll keep trying to push his point, and refuse to listen to the truth. Not worth the hassle, which is why I stopped trying to correct his falsehoods.