Ask the TW Professor Anything About TWU, Strings, his Books, Lab Experiments, etc.!

TW Staff


Do you love our TW Professor's content as much as we do?!

Going to try and convince him (and the Wolfeman!) into recording a podcast episode or two soon so need help generating some awesome questions that excite him!

*if your question is not relevant to the topics, it will be deleted -- let's stay on track here please! :)

Let us know what questions you want answered!

TW Staff
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Injured Again

Hall of Fame
What is the thought about providing a graph that shows a string's response to varying impact forces rather than a single number which shows a string's stiffness at one specific tension and one specific impact force (and one that is not likely capable for a recreational player)? The reason for this is that two strings that have the same stiffness often feel quite different because at other impact forces, the response is different.

Similarly, what is the thought about providing a different way to represent the way a racquet flexes? Two racquets that flex in different locations and different amounts can measure to have the same RA, but will consequent feel and perform differently.



Will RA be the standard measure of flex for the foreseeable future? If not what do you see taking over as another (possibly more reliable) method?


Hello TW Professor, there are many articles you published on spin, such as the effects of string patterns, string types, tension, swing speed, and swing style. If you were to summarize your research on this topic so far, what would you say are the most important takeaways for recreational players to consider when looking for our optimal setups for spin? Thank you!


Is there a noteworthy relationship between accuracy and openness of the string pattern?

By accuracy I really do mean the standard deviation between identical lab made shots.

What is best for spin, less crosses or less mains? And how they differ in playability.

Best specs for each type of injury (e.j. Thicker handles for bad wrists, light racquets for sore shoulders, less stiffness for tennis elbow ....)

How stiffness makes a difference each part of the racquet head/ beam/ handle.

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New User
I'd like to have a better understanding of what constitutes a racket's feel between the beam type, thickness, and stiffness of a racket. The Pro Staff 90 has an RDC rating of 66 and the RF97 has a rating of 68. However, the PS90 has a flexible feeling on contact while the RF97 feels stiff as a board. Which of the three specs have the biggest impact on the flexibility of a racket and in what order? If the RF97 had the same the same 17.5mm beam thickness and shape of the 90 would they feel almost the same including the size and material differences between the two?


Gather actual samples of top line natural gut from perhaps 1980, 1990, 2010 & 2020, VS if you want to standardize. Identify the differences in construction process and dynamic properties.
Natural gut has long been a central part of our game.


Talk Tennis Guru
STRING TENSION - I have a new string, with a stiffness rating of S and gauge of D mm. Rackets have recommended tension ranges. Are there any recommendations for string tension based on Material, Gauge and Stiffness? Are there any string tension ranges based on head size and pattern? By that I mean is the recommended string tension is 50-60 lbs and I'm stringing a 16x19 MP and an 18x20 Should I try to stay at the same tension? When should or shouldn't I use a machine pre-stretch on a string?
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How much can the swing weight change as the string loses tension and the hoop slightly changes shape.

Are any string manufacturers using eco friendly packaging like recycled paper type packages?

How much does the mains tension increase after the cross is strung and it elongates the mains back out?