String Stiffness and Tension Loss

In what could very well become our most blasphemous and controversial blog entry to date, we finally respond in a public way to one of the most common questions we receive. “Why doesn’t the USRSA include the MSV and WeissCANNON strings in their annual String Selector Map?” The short and direct response is because we do not believe the data is representative of actual string performance and we choose not to provide samples for testing. Let’s use the remainder of this entry to explain our position.

First of all, we believe the USRSA does a commendable job in offering data, resources and information for all levels of stringers. We are a proud member of this organization and regularly use the tools and information provided because it adds value to our services. At the same time we do not agree with everything the USRSA does. There are three areas where we have significant differences of opinion. The first lies in the certification process used for Certified Stringers (CS) and Master Racquet Technicians (MRT’s). The second is the process used for collecting and measuring data for the String Selector Map. The third is the annual string survey. We will set aside the first and third issues for another day and focus on issue #2 in this blog entry.

The process the USRSA uses to collect the data involves testing a single swatch of string, less than 1′ in length. This single strand is tensioned and then allowed to sit for 200 seconds. (That is approximately 3.5 minutes), It is then impacted 5 times with a test hammer to approximate the impact of a 120mph serve. Deflection is measured to determine the stiffness of the string. Tension loss is measured using a process that in not clear to us, but it is clear that the string is not likely tensioned for 5 minutes before the measurement is taken.

While the data these tests produces is indeed interesting, we do not believe it clearly represents the performance of the string in the context of a full stringbed. In fact, there are many examples where the data indicates strings are stiffer or softer than they actually perform. For example, it would be difficult to find any player who will tell you that Prince Synthetic Gut plays stiffer than Prince Synthetic Gut with Duraflex, yet this is precisely what the test data published by the USRSA indicates. (There are numerous examples such as this.) In terms of tension loss, the data collected from a full stringbed over a 24 hour or longer period (such as those measurements used in the blind string tests) is clearly more representative of how the string actually performs in a real-world context as opposed to how a 1′ piece of string performs in a laboratory setting.

Again, we believe the lab data is interesting, but NOT truly representative of how strings actually perform in the context of a full stringbed. The trouble is many dualistic thinkers view, digest and take this data to heart. They believe that because a perceived authority, the USRSA, has published this data it must be 100% accurate. The CONTEXT of data is not understood or considered. The results are perceived as ABSOLUTE even when the lab data may not truly reflect how the string will perform in actual playing situations.

Rather than have players draw inaccurate perceptions based on data that may or may not reflect actual performance, we prefer to encourage players to playtest the strings for themselves so they can take their own measurements and draw their own conclusions about stiffness and tension loss. We playtest each of the strings we carry. We measure their tension maintenance. We try to make this information readily available to our customers. We make every effort to objectively provide comparisons to other strings when approached by our customers. We do not believe that accurate conclusions about how a string will perform can be drawn by solely using the USRSA lab data, yet this is precisely what too many do. The number of inquiries we get that say “X string has a stiffness of 202 in the USRSA data, what is the stiffness of Y string?” is staggering. When probing those who submit such inquiries we learn they are trying to draw hard and fast conclusions about strings using this data. We do not believe this is an effective or accurate use of the USRSA data.

The bottom line is we strongly believe many strings will perform differently in the context of a full stringbed than they will as a single tensioned strand in a laboratory setting. Because of this belief, we choose not to include the strings we represent in the current testing. If the USRSA changes their methods and uses a process by which a full stringbed becomes the baseline for testing, we will be happy to consider having the strings we represent included.

So there you have it. Please feel free to comment. I’ll start by adding a closing comment to myself…

John, you have just blown to bits any chance, however small it may have been, of being named as a USRSA retailer or stringer of the year, WTG goofy!

This entry was posted in Poo-Poo Platter, Stringing. Bookmark the permalink.

6 Responses to String Stiffness and Tension Loss

  1. EP says:

    Have you looked up or heard from any of your string manufacturers whether the UKRSA or ERSA has some tension loss/string stiffness measurements that would be more useful than the USRSA’s?

    Also, you’ll have to fill me in on your issues with the USRSA’s certifications sometime if it’s going to be some time before you put that up. I’ve taken neither myself.

    • ggtennis says:

      @EP Thank you for your comment. We do not know of any organization measuring stiffness and tension loss in the context of a full stringbed. The process would be time consuming and there are variables that would be difficult to control. Still, I believe more representative data could be accomplished using a less efficient, but more realistic process.

      As for the certification issue, my basic objection is that the current system lacks rigor and oversight. The credential is more like a general seal of approval that is too easily earned. I know of many who are CS and worse yet, MRT’s who manage to pass the testing process, but do not live up to the quality standards that are stated by the certifying organization. In my opinion, at this time, the credential is not worth the cost. If I were king for a day of the USRSA I would institute a rigorous multi-day institute for those who wanted to become certified. It would be comprehensive and thorough. I would also mandate some form of on-site evaluation process for renewal of the certification.

  2. PKS says:

    great blog. they can easily measure a full string bed. only time will tell

  3. Speckman says:

    Well, I’ve heard similar arguments before regarding the validity of the USRSA’s tension and stiffness testing. My own conclusion, based on other sources, meshes with yours: the tests are limited, but do provide some data that can be used for tentative comparison purposes.

    However, combined with playtest reports, anecdotes on message boards and scattered tension loss data found on sites like, I feel that the USRSA data is especially valuable simply because it covers such a comprehensive range of available strings and string types.

    Also, I’m an American currently living in a totalitarian state abroad. Based on my experiences here I’m more convinced than ever that more information is better – Always. The most informed electorate elects the best candidate; the most informed consumer selects the best product. Period.

    Therefore, because you have admitted that the USRSA tests do have some limited validity, I think excluding Weiscannon and MSV strings from this testing is a mistake. These brands have reputations that precede them – it is unlikely that any unfavorable data would harm that reputation at this stage. But, to my mind, knowing that they have been willingly ‘protected’ from this testing actually makes me less interested in trying these products. All other major brands have been tested using this limited USRSA protocol – so it’s a level playing field.

    Now, I’ve injected a good deal more gravity into this post than strings deserve, and by no means do I intend to compare dictatorships and ggtennis. But I say: test the strings and let the chips fall where they may.

    Finally, I wouldn’t have posted this comment at all, except for your last statement:

    “The bottom line is we strongly believe many strings will perform differently in the context of a full stringbed than they will as a single tensioned strand in a laboratory setting. Because of this belief, we choose not to include the strings we represent in the current testing. If the USRSA changes their methods and uses a process by which a full stringbed becomes the baseline for testing, we will be happy to consider having the strings we represent included.”

    What struck me is that you say, if the USRSA were to use a full stringbed test in future, as you recommend, you will CONSIDER having your strings included in such tests. If your motivation is truly to make sure that accurate information about strings is available to the public I would have expected you to write that you CERTAINLY WILL submit your strings to the scrutiny of the kind of testing that you yourself recommend.

    BTW, are MSV and Weiscannon strings made available for USRSA blind playtesting?

  4. ggtennis says:

    @ Speckman
    Thank you for your thoughtful comment and the time you took to articulate your thoughts.

    The reason we did not absolutely commit to the type testing we proposed is because we would first want to make sure there were consistency standards in place. i.e. What racquet would be used? Would they be strung on the same machine by the same stringer? Would they have multiples of the test racquet so once the test racquet received X# of stringings it could be retired and a new racquet used? I would want to be assured that steps were being taken to make sure the tests were as consistent as possible. Again, it would be very complex and difficult, but if performed with a clearly defined test standard, we would DEFINITELY participate.

    WC and MSV strings are not currently made available for blind playtesting by the USRSA. For that type of data, StringForum is a useful resource.

  5. Chris Rizutto says:

    The MSV tests would have been dismal. They drop in tension big time and they are very stiff. I bet the Weiss Cannon strings would have performed well. Wish you would have sent them all in for testing.

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