Category Archives: Tips

What is Elongation?

In dictionary terms it is:

“the amount of extension of an object under stress.”

In tennis terms, it means the same thing when talking about tennis racquet strings.

How much does a string stretch under the reference tension load or otherwise stretched (impact)?  The proliferation of wrist, arm and shoulder injury has brought attention to the property of “stiffness.”  The problem is that your stiffness may be different than my stiffness, so there needs to be an “index” associated with each string, in my opinion.  I have that data on over 500 tennis strings, but that is just me.

The images show the results of high elongation (left) and low elongation (right) string upon breaking.

Several years ago a player asked me “where is the string that is missing?”  Well, it is not missing.  The ends you see should be connected!

If the string has little elongation when it breaks there is nothing “pulling” it apart like the high elongation string. So each time you hit the ball, the string either elongates a bunch or it doesn’t.

In the case of the high elongation string, on the left, it absorbs a good portion of the “shock” associated with a hard hit, whereas the low elongation string, on the right, lets your body do the absorbing to a great extent.

So, it is reasonable to use very low reference tensions for low elongation string (35 to 45 pounds; 16 to 20.5 Kg) and higher tensions (45 to 60 pounds; 20.5 to 27.2 Kg) for high elongation strings.

You may ask, “how do I know how stiff a string is?”  If you see the word “polyester or co-polyester” it is likely that string wil be stiff compared to natural gut, most nylon based multi-filament construction, and PEEK (Zyex) material.  In my opinion, there is no “bad” string just “bad” applications.  If in doubt…ask!

Brittany Tagliareni…a Winner!

In all the years I have been involved in tennis racquets I have worked with players of all levels, from top-ranked to no ranking at all!  The one thing that remains constant is that every player received the same attention to a goal.

Typically that goal is to win!

As I reflect on the high points of this journey there are a few players that really stand out. One of those players is Brittany Tagliareni.

  • Brittany is one of the best tennis players in the world.
  • Brittany has won many awards and accolades from the tennis community and press.
  • Brittany is Autistic.

Here is the deal. Every day I talk to players about the most minuscule of performance specifications…one (1) gram here, one gram there, one (1) pound here, and so on.

Brittany is different.

Brittany is very busy and wants to get to her next function whether it is taking care of dogs or tennis!  She really doens’t want to talk to me about tennis racquets!

So, to really understand what needs to be done her mother, Catherine, communicates for Brittany.

Brittany plays with a Yonex SV100 racquet strung with Ashaway Monogut ZX at 46 pounds.

She travels with three (3) matched racquets. This is where it gets interesting and one of the reasons I wanted to write this post.

Brittany needed some extra encouragement to hold the racquet with the proper grip (she is left-handed) to generate the amount of spin her coach wanted her to have. Just telling Brittany how to hold the racquet was not consistently working so we re-shaped the grip to offer some tactile “encouragement”.

The grip has been changed to have different “feelings” for each bevel of the grip shape. So one side is exaggerated for a certain length on the grip and other sides were accentuated shape wise.

The grip re-shaping had to be done in a laminated way because it works, is expedient, and minimizes costs associated with major grip modifications.

Now when Brittany holds the racquet she can feel exactly where it needs to be.

Brittany goes to Washington, and beyond!

See what Brittany has accomplished.

Brittany is incredibly busy so it is difficult to keep up with all of her travels.  Most recently she was in Dubai!

Keep it Up!

I am talking about our String Frequency Calculator tool.  As of right now, as far as I know, WordPress does not support “interactive” spreadsheets, so our calculator is far, far, away running on One Drive!

Each time you enter user information it goes to the “cloud” and the calculation is made, then returned to racqeutquest.com, and you.  It seems like a long way around but for now, that is what we have.

Here is how you can help.  One Drive puts the application to “sleep” if the spreadsheet is not “active” for a short period.  Then it has to be “jump started” which causes the blank display you may see.  The fix is to keep it active!  So every five (5) minutes or so do a calculation!

We think the information is fun and meaningful so please continue to use the Stringing Frequency Calculator!

This is Important!

I was just going through some older posts and came across this “E” Book post and believe it is more relevant now that when I originally posted it!

Take a look because this is important!

What is Soft…er?

MonoGut ZX +ZX Pro…let’s talk about it.

If you have been around Racquet Quest for a while, you know we talk a lot about Ashaway MonoGut ZX and ZX Pro, with ZX Pro being the 17 gauge version. During this post when I use MonoGut ZX it will include the ZX Pro Version, to save pixels!

A few questions need to be answered before we begin:

1. Do you get paid to talk about Ashaway MonoGut ZX?………. No
2. Do you get Ashaway MonoGut ZX free?………. No
3. Do get to spend the summer at a lavish resort in Ashaway R.I. ………. No
4. Why do you do it, then?

The short answer is MonoGut ZX works in so many applications that it is impossible not to talk about it whenever talking about tennis racquet string, arm issues, durability, and performance!

The first thing we need to know about MonoGut ZX is that is not polyester. It is Polyetheretherketone, or PEEK, for short. MonoGut ZX can look exactly like many common polyester strings due to the monofilament format. Monofilament means it is one strand of material and is typically very smooth and shiny.

The appearance is where the similarities end. Without going into a lot of detail, the stiffness of the base material dictates the stiffness of the string, especially in monofilament formats. Every string we get is tested for “stiffness” and entered into our database. This stiffness is converted to Power Potential using proprietary software. Power Potential is easy to understand…the higher the number, the more powerful the string is.

To get to the meat of this topic, we need to know the relative values of these materials.

MonoGut ZX has a power potential of 14.62
Babolat RPM Blast has a power potential of 4.29
LaserFibre Silverline 2 has a power potential of 4.59
Luxilon ALU Power has a power potential of 4.42
Luxilon ALU Power Soft has a power potential of 5.72

There are hundreds of polyester based string, but this gives you some idea as to where they stack up vis-a-vis MonoGut ZX.

Why does this matter? Strings with very low elongation (power potential) get stiffer the harder the ball is hit! So what? So, if you have low power potential, you need to swing harder to get the ball to go as far as it needs to go especially if you are trying to hit with huge topspin.

MonoGut ZX is suited to many playing styles, racquets, and string patterns. That is why so many really good players are currently using it and winning with it.  That is why it is important that we continue to talk about MonoGut ZX!

Maybe it is time to try MonoGut ZX yourself.

Ashaway MonoGut ZX Black

Ashaway MonoGut ZX Pro Natural

After the String is Strung!

I have often wondered what players know about the “stringing” process and in particular what goes on after the “string is strung”.  So, while Madelyn was here she decided to video me doing what we do after each racquet is strung and just coming off the machine.

Had I known we were going to do this I might have dressed up a little, emptied the trash and fixed the crack in the wall behind the RDC!  But I didn’t.

This video is offered as a “real-time” view of what we do with every racquet and is intended for information and fun only.  If you have any questions please let us know…now enjoy the movie!

And Now This…

In the words of Lord Kelvin (May 1883) “When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts advanced to the stage of science.”

That is why every racquet we do has over fifty (50) numbers attached to the finished data. Most of these numbers will remain unknown to the client, but for us, it is imperative that we know them.

Numbers Matter!

Which leads me, again, to this very important discussion.

Every day we see a statement from tennis string manufactures claiming, or suggesting, their string is the “softest ever tested” and other claims.  What the heck is “soft” anyway?  There is a lot more to it than meets the eye so we have done significant analysis on bunches of string and can now quantify “soft” as it relates to tennis string.

What is “soft”?
In 1994 I did a presentation for the USRSA in Atlanta. What was the topic?

“Understanding String.”

It is now 2016, and we are still trying to understand string! Especially “soft” polyester based string.

In 1994 PolyStar was the only polyester based string I was familiar with. Since then there are dozens of offerings from anyone that can afford to purchase from manufacturers and market the string. If you have a desire to do it, I applaud you!

In 1989 I started testing string and calculating “power potential.” Why “power potential”? Because “modulus,” “elongation” and “elasticity” didn’t get to the bottom line of string performance quickly enough! The steps to arrive at power potential are many.

For the testing, several calculations take place including “stretching” the string as in a ball impact. The difference between the first calculation and the “stretched” calculation is the power potential!

I have calculated hundreds of power potentials but have not until now quantified “soft.”

I think now is the time!

Under the direction of Dr. Rich Zarda, we have done a tremendous amount of work on this issue so we can now distill this work into the following explanation.

So, what is a “soft” tennis string?

Strings in a tennis racquet carry the ball impact load in two ways:
1) Via the pre-load string tension placed in the strings caused by a stringing machine (and the racquet frame “holding” those tensions in place) and
2) Via additional tensions that develop in the same string caused by the elongation of the strings as they deflect with ball impact.

Both of these conditions occur simultaneously and contribute to the string bed stiffness (SBS, units of lbs./in). Racquet technicians measure SBS by applying a load to the center of a supported string bed and measuring the resulting deflection. Dividing the load by the deflection provides the SBS (lbs./in). The lower the SBS, the more power you have (power here is the ability of the ball to easily rebound from the string bed), but the less control (presumably); the higher the SBS, the less power you have but, the more control you have (presumably).

One more point about SBS: the lower the SBS, the less the load your body will feel for a given swing. But for an SBS too low (less than 50-80 lbs./in), balls will be flying off your racquet going over the fence; and for an SBS too high (greater than 200-240 lbs./in), the racquet will hit like a board with significantly less ball rebound. So the most common SBSs are between 100-200 lbs./in: a balance between control and power.

As already expressed, SBS is a function of the pulled string tension and the string elongation. Here is what is interesting: For large string elongations (for example, greater than 15%) and reasonably pulled string tensions (greater than 30-40 lbs.), SBS only depends on the pulled string tension, and it does not depend on string elongation. Additionally, for this condition, SBS, for these high elongation strings, does not change as a ball is hit with more impact.

linearity_noname

But for a string bed with low elongation strings (less than 5%) under low pulled tensions (less than 20 lbs., or tensions that have been reduced due to racquet deformation and/or string tension relaxing with time), the SBS additionally depends on the string elongation and will significantly increase, in a nonlinear ever-increasing way, for harder ball impacts.

In order to achieve a repetitive feel for a player when hitting with a racquet, it is best to have an SBS that is independent of an increasing ball impact force. This will lead to a more consistent playability of the racquet, which includes a more repetitive feel. This desired “feel” implies using high elongation strings (greater than 10%). If low elongation strings are used (less than 4%), the SBS will significantly increase as the ball impact force increases, resulting in a racquet feeling “boardy” for higher impact loads. And low elongation strings will cause un-proportionally increasing load into the body.

deflections

As you can see by the graph, elongation contributes to SBS in a big way. The red line indicates a stiff string, about 4%, and the blue line indicates a “soft” string, about 15% elongation. You can see the loads increase dramatically as the impact increases. So the harder the hit the higher the loads on the body.

So to the question asked at the start “What is a soft tennis string?” In the context of the SBS discussed above, I would suggest that a soft tennis string is one whose elongation is 10-15%, and a stiff tennis string is 4-6%. And any string under 4% should be categorized as ultra-stiff.

String elongation (soft, stiff, ultra-stiff),  stringing machine strung tension, and string pattern(s) all contribute to SBS and SBS is an important measure of how a racquet plays and should be adjusted for an individual player, stiff and ultra-stiff strings can lead to less-repeatable racquet performance and player injury.

Soft = 10 -15% Elongation                Power Potential Range = 10.0 – 16.0
Stiff = 4 – 6% Elongation                   Power Potential Range = 4.0 – 7.0
Ultra Stiff =  Less than 4%               Power Potential Range = .65 – 3.96

 

Need Direction?

A client just sent me the following statement and I think it has reason to be distributed amongst tennis players searching for “direction” when it comes to string and their game!

“Hah. Trying out these different strings has been very interesting. Over the past week or so, trying the different strings has given me some insight into what my game should be. I think usually people do it in reverse. They try to find the string that tailors to their game. By experimenting with the strings, I realize the direction my game should be going.”

“I’ve been coming to realize that my game is better with control and feel rather than power.  Experimenting with different strings have helped me recognize this.”

Do you think this applies to you?

Shaped String Considerations

Monofilament string can be easily produced in almost any shape.  Round, square, triangular, hexagonal, octagonal etc.  So, on the surface that seems like a good thing.  Who wouldn’t want the sharp edges digging into the ball creating even more spin!

But, there may be a side to the shape that needs considering and that is tension as it is applied to the string vs tension as it is in the racquet.  Those can be two very different things!

When the main strings (the long ones usually) are installed they are free to move and will normally be only slightly “twisted”.  This is more obvious with square and triangular strings.

Cross String Twist

This image shows one of the lower cross strings and the “twist” is obvious.  So what?

So the tension on these strings will be considerably lower than expected.

Why?  The machine tension head is set to pull each string to the desired setting, say 50 pounds.  When the machine “feels” 50 pounds the tension head stops.  The cross string will twist, just like a screw, as it passes over and under the main string.  A twisted string will not pull through the adjacent main strings easily so the tension will, in this area, be less than desired.

This variation in “tension” can affect the way a ball comes off the racquet.

We use string spreading devices for every racquet and every type and shape of string.  The “spreaders” raise and lower the main strings so there is no friction (twisting) between the cross string and the main string.

Not all racquet technicians use this type of device, so,  the twisting can be mitigated by weaving the appropriate cross stings over and under the main string one at a time making sure they are not twisted and then apply the machine tension.  This will result in a more consistent result.

If your racquet has cross strings that look like the image be sure to mention it to the stringer so it can be remedied.

 

Hybrid Stringing…What is it and Does it Matter?

When the discussion is about stiff polyester string, it will always include the word “hybrid”!  Typically this word is used to convince players that by putting a “soft” multi-filament string in the cross position the string bed will be easier on the wrist, elbow, and shoulder.

Intuitively this makes sense, but in reality, the reverse could be true!

I began analyzing hybrid string beds years ago and did many just to test the theory. At the time it did not seem so important because, frankly, the use of polyester based string did not approach the usage of current times.

I have nothing against the polyester string(s)! I do have an issue with bad applications of polyester string(s).

I am bringing this up again because recently an “interviewee” stated that that replacing the polyester cross string with a multi-filament would cure the ills of a very stiff string bed.

The bottom line:

A high elongation string of any material can increase the string bed stiffness of a hybrid string bed!

How can this be?

Stiff (polyester) strings are “stiff” and the tension applied to them during stringing is low. However, high elongation (multi-filament) strings will be influenced more by tension and become “stiffer”.  The cross stings are typically shorter, and there are more of them, so the combined affect is stiffness.

The initial reaction to this conundrum is to automatically reduce tension on the cross string by a certain amount. Again this raises another issue, and that is racquet distortion.

During the installation of the main strings most stringing machines will allow the racquet to become wider, sometimes a lot wider! So, reducing the cross string tension may not return the racquet to the designed shape. What happens then is the racquet will continue to move around trying to find a “safe” place and therefore the string bed stiffness changes.

In summary, the hybrid string bed will not be statistically different than the full string bed of polyester. This is even truer if the initial string tensions of the polyester are very low, such as 35 to 40 pounds.

So if you feel the need to use polyester just go with lower, lower,  tensions.

 

 

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