TW University investigates what happens when tennis strings go dead

Why do strings go dead?

In a recent article by our TW University Professor Crawford Lindsey titled “How Tennis Strings ‘Go Dead’”, he decided to tackle an age old complaint of almost any avid tennis player.  What actually happens when tennis strings “go dead” as they sit in a racquet over time?  And why are there often times contradictory reports between players?  Some people will think that their strings feel loose, gain power and lose control, while other think they get mushy, low-powered and lose their spin potential.

The TW Professor conducted a number of tests on a variety of strings to see what actually happens to strings over time.  He used a number of different methods to simulate the repeated use of the strings, and then took a variety of measurements in order to determine what factors were at play in this perceived loss in playability.

TW Professor Crawford Lindsey conducts tests with a kettlebell to simulate the repeated use of a string.

TW Professor Crawford Lindsey conducts tests with a kettlebell to simulate the repeated use of a string.

What he found was that there are two changes worth noting that happen to strings over time.  The first and most obvious one is that the strings stretch and lose tension over time, making the stringbed less stiff and more “springy.”  When this happens, the ball sinks into the strings and stays there for just a fraction of a second longer at impact, sending the ball off at a slightly higher trajectory than usual.  This causes the ball to travel farther, which most players will perceive as an increase in power or a loss of control.  This takes care of one common complaint.

The second change is a little less obvious.  The Professor found that over time, due to wear and tear, the strings tend to stick to each other more, creating more friction between the strings.  Now, let’s take a step back and recall what we’ve learned in a previous article…When a ball hits the strings, it moves the main strings out of position (ever so slightly), and as the ball leaves the racquet the strings snap back into their original position.  The more snap back action there is, the more spin a string can produce and the more comfortable it feels to the player.  As the strings wear down and more friction is created, what results is less efficient snap back of the main strings when they slide out of position at contact.  The less the strings move, the less spin they will produce and the more stiff and dead they will feel.

These two things, tension loss and an increase in friction over time, happen to every set of strings, regardless of the type of string or the tension they are strung at.  Each string is unique in that these changes happen at different rates depending on the string.  One string may lose tension quickly but not lose its ability to slide on itself, in which case it will feel like it gains power and loses control.  Another string may keep its tension but start to stick to itself more, resulting in less spin and power and the feeling the strings are “going dead”.  The interplay between these factors is crucial to what the player feels over time and why the perception is different from player to player.  As Crawford so eloquently says in the conclusion of his article, “The strings are simultaneously gaining and losing in power behaviors or in stiffness and softness characteristics. It is the net effect that determines the player’s perception of string performance.”

Hopefully now you have a better understanding of what occurs as strings stay in your racquet.  Stay tuned for more interesting discoveries and articles from our TW University!

Thanks for reading!

AG

 

Tennis strings that produce the most spin

Rafael Nadal's "buggy-whip" forehand is being emulated by junior players all around the world trying to generate the most topspin that they can on their forehand.

Rafael Nadal’s “buggy-whip” forehand is being emulated by junior players all around the world in an attempt to generate as much topspin as they can with their forehands.  Photo courtesy of Cynthia Lum.

Tennis players of all levels have gone crazy for spin in recent years! With the latest racquet and string technology along with younger players trying to replicate the modern swings of Rafael Nadal and Novak Djokovic, players are trying to maximize the amount of spin in their games as best as they can.

Our TW University Professor Crawford Lindsey has done extensive testing on how spin is produced during a shot, and what factors apart from the stroke itself aid or hamper the production of spin. At contact, the ball hits the stringbed and moves the main strings (the strings that are horizontal at impact), sliding them out of position vertically against the cross strings. As the ball leaves the strings, the main strings snap back into their original position. A string’s ability to slide and snap back efficiently is what our TW Professor concluded to be the biggest difference between strings in terms of their spin potential. Therefore, the further the main strings can stretch during this process, the greater the snap back force is, and thus the more spin you can generate.
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How string patterns affect spin

Spin is in with the new super open string patterns by Wilson

Spin is in with the new super open string patterns by Wilson

With the release of the new Wilson Spin Effect racquets, the Steam 99 S and Steam 105 S, people are talking about the way that spin is produced and what effects a racquet can have on spin production. Wilson utilizes an open 16×15 string pattern that it claims helps to produce noticeably more spin than a traditional 16×18 or 18×20 string pattern. The difference lies in there being fewer cross strings than main strings, thus opening up the stringbed and creating more space in between the strings.

Interestingly enough, our TW University professor, Crawford Lindsey, was onto something very similar a few years ago when he started testing the effects that different string patterns had on spin. He conducted experiments (outlined in his “Spin and String Pattern” article in September of 2010) to test which string patterns were more effective in producing more spin.

This picture simulates the stretching of the main strings at contact, which is what helps produce topspin.

This picture simulates the stretching of the main strings at contact, which is what helps produce topspin.

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