When you unfortunately break string at match point, it’s pretty obvious that you’ll need to switch rackets… However, you’ll find that in practice you won’t always break a string while still feeling your stringbed is going ‘dead’ after a while. What’s more, some players haven’t broken a string in years. So, is there an objective rule to determine how often you should restring your racket?
Basically, there is a practical answer and a scientific answer. Our practical answer is mostly concerned with string breakage and this scientific answer focusses more on tension loss. We will adres both in this post. In practice, we found that there is no way to establish a good rule of thumb for when exactly you string will break. It depends too much on other factors. We base this upon our own years of stringing experience, talking to and interviewing our clients, looking at playing frequency, technique, material, frames and so on. The only general advice we can give you here is to at least change your strings once a season, as tension will definitely drop over time and strings tend to dry out a bit. However, when we focus on tension loss, we can argue that you should definitely get a restring after your stringbed stiffness (which we will explain in detail in this post) has dropped by 20 percent. Obviously, your string didn’t break yet in this phase, but the feel of your shots will have became less satisfying and your unforced errors will have probably increased.
To cut a long story short, we decided to write this article because we wanted to address this persistent belief within the stringing community. We are not sure of when and where, but it seems to be an established rule of thumb that the best way to decide how often you should restring your racket is as follows.
“How many times you play per week is approximately the number of times you should restring your racket per year.”
I’ve been thinking about a decent way of putting this… this rule is total nonsense.
It absolutely depends on a variety of factors not mentioned in this formula, although there surely could be a group of players for which this ‘magical’ formula might apply. For the rest, my advice is to forget it as quickly as you can.
Accounting for different elements
Ok, so why is this rule of thumb so worthless then? Well, because the art of stringing is all about accounting for different elements of your gear and playing style and you guessed it… that’s very unique for each player.
- So let’s start with the most obvious one: your choice of string. Let’s say all other things being equal, playing with a synthetic gut as opposed to playing with a stiff poly will definitely change the outcome of the total number of restrings you’ll need. This is true for intermediate players and even more so for advanced players. It’s just the physical properties of playing with these type of strings that make them wear down more quickly.
- Secondly, your level of play and power level will heavenly influence the amount of strings you will break per season. Let’s say I just started out playing on a beginner level and have a control oriented style of play which focusses on keep the ball in play while minimising spin. Now compare this to a 6″2 heavy hitting power player that uses spin on his serve and plays with a ability to produce a lot of winners. Totally different ball game right there.
- Third, the frame, string pattern and grommet system you choose will also have a big influence. All in all, most rackets will have the same effect on string wear and tear but there are some frames who actually do a terrible job on this aspect. Consider the O-Zone frames by Prince with some great features in terms of playability and power, actually are a disaster for your wallet. While paint chips are breaking away from the O-ports, your string is being exposed to the actual graphite fibers all around the ports.
- Fourth, frequency of play will surely influence string breakage. However, this has much more to do with the elements described above then frequency as a factor by itself. Are you a heavy hitter and are playing almost every day? Prepare to buy some strings in bulk? Pretty advanced but defending player keeping the ball in play? You’d be surprised how long you’ll be able to play with some strings.
- Fifth, playing conditions will surely impact how long your strings will last and warm conditions almost always shorten the life span of your strings, even though the ball will fly through the air a bit faster which might cause you to hit the ball with a bit less power. Hight temperatures will definitely increase tension loss and that’s why you should never leave your rackets in a car on a hot summer day for example… Once tension is gone, it’s gone for good.
Stringbed stiffness and tension loss
Now we know that focussing on string breakage is only part of the answer, how about tension loss? Well, as mentioned before, there is a good understanding in literature of tension loss and loss of feel or consistency in play that increases while tension loss increases, and it is stated that the best moment to go for a restring while your string is still without breaking is around a 20 percent decrease of so called stringbed stiffness.
Stringbed is the keyword
First of all, it’s good to understand that strings are only one part of the stringbed system. In this context, stringbed is the keyword. In the course of time, all great racket and string manufacturers have contributed to releasing new technologies when it comes to the performance of the string plane, like head size, string pattern, suspension systems, string materials, gauge and tension. However, what the combination all these different developments boil down to is actually pretty simple – affecting the total stiffness of the racket stringbed. This is often difficult to read in between bold marketing statements of brands that actually aren’t very accurate. But in fact it’s just the increasing or decreasing stringbed stiffness that really impacts play in a meaningful way.
There is no ‘good’ or ‘bad’ value
Also, it’s good to realise at this point that there is no good or bad, because some players will like different values for different reasons. Some players might find a softer string ‘comfortable’, while others might find it ‘mushy’. Some players might find a stiffer string ‘crisp’, while others will call it ‘harsh’. This means that the one thing we can more objectively understand is consistency of your stringbed. When we take a look at strings it is also true that the combination of string material, construction, gauge and tension all influence string stiffness and in turn affect stringbed stiffness, which in turn affects power, control and feel of your frame.
Dynamic and static stringbed stiffness
Stringbed stifness is measured in two ways. Dynamic stiffness refers to how much the stringbed will deflect perpendicular to the strings when it is impacted by an object (with a given amount of energy). It is the most relevant value, but also a bit more complicated to measure, so you won’t find this on packaging materials. The most common method of measuring stringbed stiffness is a static stiffness test. This method measures the string deflection when a force is applied slowly to a certain area of the stringbed (normally the center of the stringbed). The deflection is result of all the stringbed factors described above.
You can control string material and tension
The one thing to remember for now is, given the racket you are playing with, string material and tension are the most important factors in stringbed performance because in the end, they are all you can really change on a day-to-day basis. When you change the stringbed stiffness, you are primarily altering the feel (shock and vibration) and control. Changing stringbed stiffness does not have an effect on spin and just a small effect on power.
Tension and power
If you change the stringbed stiffness by raising tension or changing to a stiffer material, then the stringbed will be stiffer than the ball and will not deflect as much. As a result, the ball will compress more. More energy is directed into the ball (of which it loses about 45 percent!) and the ejection speed of the ball is less. The opposite is true if you decrease the stringbed stiffness by lowering tension. The strings will absorb a greater share of the impact energy, leaving less for the ball to loose.
So, how much extra ball speed you want to know, right? Well, it’s not as great as you might think… It’s not that the old saying “string loose for power, tight for control” is not true, just not to the extend that most people claim. If you drop tension by 10 pounds (or 4.5 kilograms), the percentage gain in ball velocity will be less than two percent, or about 1.2 miles per hour on 60 miles per hour groundstroke. Well, isn’t that a reality check…
However, the ball tends to land a bit deeper in the court at lower tensions because of three reasons. First, it actually is travelling a bit faster so it get’s a bit further in the court for the same amount of travel time. Second, because the ball stays on the racket longer with looser strings, the player will swing through a larger vertical arc during this time, and the ball will therefore, take off at a higher angle and travel a bit further. In addition, the launch angle relative to the court will also be relatively higher by looser strings and this might even be the most important. Perhaps we should revise the old adage to “string loose for depth, and tight for safety”.
Tension loss and going ‘dead’
When a string loses tension, it becomes softer. That’s basically all that changes in a string. It does not lose power, resiliency or go ‘dead’ in a way that we can actually measure. It simply becomes less stiff, and thus feels different to the player. A string does not lose resiliency, meaning it will also return to its pre-impact length every time. Of course, if it wouldn’t, your strings would start to sag in the middle. Nor does a string lose elasticity. And old string used for many years will stretch less than when it was new, but it will still return 95 percent of its elastic stretch energy when impacted.
However, many players describe a phenomenon as their strings going ‘dead’, what basically means that their string has lost tension. It hasn’t lost power or the power to return energy. The string power is the same, if not more. It is known that as tension declines, the string actually takes in, and thus gives back, more energy (which translates to ball velocity). So practically, ‘dead’ equals not less power or ball velocity, but diminished force of impact, shock and feedback – in other words, less ‘feel’.
Consistency of feel is very important for maintaining a good level of play. This is exactly why top players have so many rackets strung.
Tension loss and feel
You don’t get the same ‘punch’ when you hit the ball with decreased tension. Because you have actually lost ‘control’, as you notice by seeing the ball travel further into the court, you may back off your stroke speed, which lessens the feel of impact even more. So you haven’t lost power itself, but you have actually lost the feel of providing the power, being in control and getting the right feedback confirmation from the racket punch. Not as much feedback basically is not as much ‘shock’. So when you choose a string, you are actually choosing the level of shock that feels good to you.
However, the rate of loss continually slows down and eventually stabilises with time. So for example, a relatively ‘fast changing’ string may still be slow enough to stay within your own ‘feel range’ for an acceptable amount of playing time. That will depend on your sensitivity and response to change.
Nonetheless, a rule of thumb does apply. The amount of tension loss is irrelevant as long as the remaining stiffness feels good to you. So, tension loss is in itself necessarily a good or a bad thing. But, if you are not satisfied with how long your string matins it’s ‘feel’, then try a string of the same stiffness but that loses less tension over time.
Tension loss and control
Losing tension affects control in a couple of ways. First, as mentioned before, lower tension will result in a slightly faster ball that will travel a bit further with the same swing. Secondly, a lower tension results in a longer dwell time. This means that ball stays on the strings for a longer time. The angle of your shot will be therefore at a higher point and create a higher angle. And third, if you hit off center, the ball will twist the racket for a longer time, also resulting in a different angle launch.
So players sometimes refer to the combination of this effect as a “trampoline effect” or something like “the ball flies all over the place”… which leaves you as a player with only one thing to do: increase the stringbed by increasing tension or choosing a stiffer string.
Tension loss and sound
The importance of hearing your impact is demonstrated by one very striking fact: about half of all players can’t play without a string dampener, and the other half can’t play with one. This auditory cue, or lack thereof, is rather necessary to most players in terms of feedback as to the quality of their shot. Some like to hear the ‘thing’ and others find it difficult to listen to.
Losing tension changes the sound of the impact. The pitch is lower. You can go from a ‘twing’ to a ‘twang’. The first sound more responsive, elastic, and crisp that the second one. A lower pitch will affect the psychology of your play. Of course, the secret is to tune your strings. So, the stiffer the string, the more you’ll ping!
Tension loss and prestretching
When a string is stretched and tied off at it’s stretched length, the tension starts dropping immediately (actually it will drop off even while still in the machine). You could theoretically restore the tension by undoing the string and stretching and tying it again, and after which it would drop in tension again. However, the second time around not as much and quickly as the first time around. Some players therefore like to pre-stretch their strings once or twice before installing it in their rackets. This almost every time the case for players who play with natural gut. By pre-stretching you can slow the tension loss, but the string will also play stiffer at any given tension because some of the stretch will be taken out of it. Alternatively, it is simpler to string the racket at a higher tension than in the first case.
Tension and spin
Another famous saying is “string tight for spin”… However, tests have shown that string tension, gauge or material virtually have no effect on spin. Yet players insists they are able to play with more spin, so who’s right?
Well, both, probably. First, because tighter strings produces less depth in your shots, a player swings harder to get extra depth. Consequently, a faster swing will then produce more spin. The second reason might be the illusion of more spin. If the ball is leaving the racket slower with tight strings but with the same spin, the spin to speed ratio will be higher and the ball will bounce as if it has more spin. So, in short, we might rewrite this saying to “string tight if you, yourself, want to add more spin”.
Tension and player perceptiveness
Almost every player will tell you he or she can tell you the difference in string tensions. You might even had some customers who wanted to return their frames because they were not on the correct tension. Although possible, tests have shown evidence that bring those claims into serious question.
“In a test of 41 advanced recreational players, only 11 (27 percent) could determine a difference of 11 pounds or less. In fact, 15 (37 percent) couldn’t correctly identify the difference even when the tension between two rackets varied by 22 pounds. A small number were able to discern a two pound difference, however. Players were not allowed to touch the strings or vibrate them to guess tension, and each racket had a vibration dampener to take away auditory cues.
Using earplugs to further dampen auditory cues lowered the succes rates even more. Players were only allowed to hit four hits with each racket, so the only data the player was interpreting was feel, not an accumulated history of location and ball placement that could be used to deduce string tension. Some players said they noticed the difference, but then incorrectly chose which racket had a higher tension.” (Cross & Lindsey, 2005)
These finding bring into question what players actually feel or think they feel. If they can’t properly differentiate string tensions, let alone the feel of power, spin and tension… what do they actually feel then? Of course, what is actually felt is the shock and vibration of the handle hitting the hand plus the push or pull on the arm. This sensation is made up of the rotation, translation and bending of the racket.
The brain has to analyse this information and turn it into our popular vocabulary, ‘feel’ for example. It is important to remember, it is our interpretation of feel, not a raw, measurable feel. The natural conclusion is that players ‘experience’ their strings. This is a holistic approach that includes feel, sight, sound, proper understanding of the placement of shots and how a player knowingly or unknowingly alters his or her strokes as a result of those shot outcomes. Finally, the player attributes this feeling as a characteristic of the tested strings, like for example “these strings have a lot of bite”.
However, we know that in the end string materials, tensions, gauge and more influence the performance of a racket and its player. Future string research should help clarify those phenomena and help us to properly talk about them, but in the meantime we will have to interpret each others common language. We hope we did a a good job clarifying just a bit right here and hope to do that for you in our future posts.