I play way more tennis than I probably should. I walk the fine line between muscle aches and injuries, and thank my lucky stars every day I survive without a sprain, strain, or other mysterious pain.
But I don’t leave it all up to my lucky stars – I’m actually pretty diligent about injury prevention. For instance, I’ve written before about how I’ve managed to play tennis pain-free with ECU tendinosis.
A big part of my stay-healthy strategy has been in making my racquet and string setup comfortable. I discussed this as part of my series on my wrist pain, but since then I’ve learned a lot about tennis strings, and thought it might be helpful to go into a bit more detail on how you can make your equipment more comfortable, particularly if you, like me, play with poly strings.
PART 1: BACKGROUND INFORMATION
Before we get into how you can make your poly setup more comfortable, I want to address a few things (I just can’t resist making these blog posts ridiculously long and complicated!)
- Do rec players “need” poly strings?
- Shouldn’t players seeking more comfort just switch to natural gut?
- String stiffness vs string-bed stiffness and how these relate to comfort
- Why this isn’t an exact science
- Side effects of soft poly string-beds
DO REC PLAYERS “NEED” POLY STRINGS?
Poly strings have a reputation for being stiff, and this is usually just accepted as a necessary evil that comes with the spin potential of the strings. So is poly worth the discomfort?
The modern game almost requires poly strings, or a partial-poly setup (at least at high levels). Virtually all professional players use poly or a hybrid with poly (polyester in the mains or crosses and another material, usually natural gut, in the other direction).
Sometimes you’ll hear that rec players don’t “need” poly strings. This is definitely true in some circumstances. Whether or not your swing will benefit from the additional torque – and therefore the added spin – put on the ball by polyester strings will depend on your stroke mechanics.
If you’re more on the beginner side of tennis, chances are you aren’t swinging like Djokovic, but instead have a slower, flatter stroke. Changing to a polyester string will not magically impart topspin on your shot.
Or maybe you’re a seasoned serve-and-volleyer who hits all your shots with a continental grip and love the crisp playability of gut. In this case, again, polyester won’t add much – if any – spin to your relatively flat stroke mechanics.
In these cases, I agree that switching to poly strings to get more spin might just not be something you want or need to do. But I also hesitate to say that beginners or any player looking to develop a modern topspin shot should stay away from poly. Certainly at the very beginning, when just making clean contact with the ball is a challenge, your strings simply won’t impact your results, but I believe that at some point players should choose the setup that will best facilitate the game they’re working towards. And this setup might very well include some polyester.
The purpose of this post isn’t to determine if you need polyester strings. This is meant for players who want to play with poly, but also don’t want their tennis elbow acting up.
Basically my overall point is that poly strings do not need to be discounted as “too stiff” for players who want to use it. There are ways to make it more comfortable and I want to share my research and experience so that people with arm/wrist issues, who like the performance of poly, can continue to use it.
SHOULDN’T I JUST USE NATURAL GUT?
Before we get into making poly more comfortable, I want to briefly address the gut vs poly debate when it comes to string comfort.
Made from the intestines of cows (at one time sheep), natural gut has a triple-helix structure with unparalleled elasticity (ability to return to original length after stretch), resiliency (how quickly and how much force it returns) and shock absorption.
When I struggled with my wrist injury a few years ago, I did try playing with a full bed of natural gut. The rumours are true – it is exceptionally comfortable. To me it felt like the ball was hitting a pillow. But while I enjoyed the comfort, I didn’t enjoy hitting the back fence on most of my groundstrokes. My topspin was nowhere to be found.
And this is where understanding how strings work can be helpful. When you change your setup to achieve a desired performance trait, you need to remember that other traits will change as well. A switch from poly strings to natural gut reduces the “over-spin” effect imparted by poly strings. Gut (on it’s own) doesn’t snap-back as well as poly and imparts less torque on the ball, thus producing less spin. Also, because it’s softer, it produces a more powerful shot. More power, combined with less spin potential, makes it tough to swing fast and keep the ball in play.
While there’s much debate over how much strings actually affect a person’s game, it’s pretty well accepted that the advent of poly strings revolutionized tennis. Its stiffness and potential to produce overspin changed how players swing at the ball and helped to create today’s spin-heavy game.
Read more in this TWU (Tennis Warehouse University) article, String “Snap-Back” and Spin, by Rod Cross and Crawford Lindsey, if you want to learn more about how poly strings produce “over-spin”.
So sure, if you want more comfort, an easy solution is to switch to natural gut strings. But for many players today, who want to swing fast and produce topspin heavy balls, this will majorly impact how you have to play the game.
I don’t mean to criticize gut or those who play with it. If you have more traditional-style, flat strokes, then it’s likely that the power reduction and spin potential of poly strings won’t benefit your game at all. In this case, gut is likely an excellent option. Or maybe for any number of other reasons gut just works for your game, and that’s great! Lucky you!
Also, gut can be used in hybrids with poly strings. This is a common setup on tour, although for rec players it has some drawbacks. We’ll discuss this later.
This article isn’t meant to debate the merits of different string materials. It’s just meant to give people who want to play with poly some ideas on how to make this a more comfortable experience.
STRING STIFFNESS VS STRING-BED STIFFNESS
String stiffness is a measurement of how much force it takes to stretch or deflect a string. Properties of the string – such as material, tension, gauge and age – all affect this measurement, so there is no one measured force for each string. Instead, a coefficient of stiffness (k) is determined experimentally for strings at the same conditions. The k value of a string can then be used to compare it’s stiffness to other strings.
The string stiffness is a key contributor to string-bed stiffness, but it’s not the only one.
To understand the difference between string stiffness and string-bed stiffness, let’s look at what happens when the racquet meets the ball.
When struck by a tennis ball, the strings in a string-bed stretch and deflect, and then they will “snap back” (or at least try to snap back) into their original positions.
In order for these movements to happen, forces resisting the movements must be overcome. The higher the tension in the strings, the more difficult it becomes to stretch them further. The stiffer the string material, the more force required to stretch and deflect them. Same goes for the thickness (or gauge) of the string. Friction forces also come into play. There needs to be enough friction between the ball and the strings to cause the ball to “grab” the strings to get them to move, but the friction between the strings themselves needs to be low enough to allow the ball to move the strings.
String stiffness is a characteristic of the string material that plays an important role but is not the only factor that determines how much, how easily and how quickly the strings in a string-bed will stretch, deflect, and return to original position. There is more at play, including things like string-ball friction, string-string friction, tension, gauge, and string pattern. These factors, taken together, are what make up the string-bed stiffness, and what will ultimately determine how the string-bed plays and feels.
The key takeaway here is that when we change variables in our setup, what we’re really doing is changing the string-bed stiffness. When we observe or perceive different results from the same swing with a different setup it’s because we’ve changed the string-bed stiffness. We’ve changed the ease with which the strings in the string-bed deform.
STRING-BED STIFFNESS AND COMFORT
Intuitively, you might think that a soft string-bed is more comfortable than a stiff one. And you’d be right!
In the article at TWU, String Stiffness — How It Works, Crawford Lindsey explains why a soft string-bed is more comfortable than a stiff string-bed. According to Lindsey, the size and duration of the collision force between ball and strings is different in soft and stiff beds. He says:
The stiff string will create a large force for a short time and the soft one a smaller force for a longer time….As for the player, being the recipient of a high force in a very short time is not pleasant. It is known as shock. That hurts. It is felt as an abrupt deceleration of the racquet, hand, and arm. It is like the difference between hitting your head against the wall or a pillow.
He also explains in the same article and others at TWU why a stiff bed produces less power than a softer one, so head over there if you’re interested in learning more about that.
A softer string-bed is more comfortable than a stiff one, and we can manipulate the string-bed stiffness by adjusting string-bed variables. This is what we’ll be discussing further down in this post.
WHY THIS ISN’T AN EXACT SCIENCE
Going into this discussion, we need to remember that adjusting our strings to get the experience we want isn’t an exact science.
Players will experience the same setup differently – even in the same racquet – and players are all looking for different results. One person might find a setup too powerful while the other loves the control she gets with it. This makes little sense from a scientific perspective – power and control typically have an inverse relationship – but string-bed performance is so subjective, and players have such different perspectives, that it’s not all about the science.
For instance, changing our setups can cause us to change our swings to compensate. A more comfortable setup is also frequently more powerful (don’t believe me? Play with a full bed of gut) so maybe you’ll change your swing geometry to get more spin and keep the ball in. Your tennis elbow might be a little sore after your first few times out, and you’ll attribute this to your new, softer, string-bed, but actually it was the change in your swing and the new movement that your body wasn’t used to. Determining cause and effect relationships are tough when there are so many elements at play.
However, even though string performance variables are complicated, intertwined, and open to interpretation, understanding the fundamentals of strings – and how changing string-bed stiffness affects things like comfort – can at least give us a starting point for experimentation.
And in my personal experience, I’ve been able to soften my string-bed so that I can use poly strings pain-free and still get the spin and control that I’m used to with these strings.
SIDE EFFECTS OF SOFTENING YOUR POLY STRING-BED
We need to remember that reducing string-bed stiffness will not ONLY have the effect of making the strings more comfortable. It will affect other variables as well, such as power, control, spin, launch angle and playability.
This post is not going to go into details about these effects, other than to say that:
IN GENERAL, FOR POLY STRINGS, softening the string-bed (and therefore increasing comfort) will:
- Increase spin potential (up to a point)
- Increase power
- Increase launch angle
- Increase playability (the strings will feel more like natural gut)
- Increase control in the sense that you should get more spin, but decrease control in the sense that your shot will be more powerful (the net effect depends on your swing geometry)
Note: these comments don’t always hold true and they mostly only apply to poly strings. I’ve done extensive reading on this at Tennis Warehouse University. Check out the string articles at TWU if you want to learn more.
How much of these effects you get and how happy you are with them depends on your specific setup, your swing, and your preferences. The trick is to experiment and find the combination of variables that works for you, and also to remember that there will be an adjustment period as you get used to your new setup.
Personally, I like the added power that I got from dropping my tension to the low forties (from high forties) this year. It took a bit to adjust to, but I’m aiming lower and hitting much more powerful shots that still have plenty of topspin to keep them in. This was an added bonus as I was really just looking for more comfort.
PART 2: HOW TO REDUCE POLY STRING-BED STIFFNESS
Ok, so now that we’ve got some background information out of the way, let’s move on to how we actually accomplish the goal of reducing string-bed stiffness while still using poly strings.
Here are 7 key ways we can reduce string-bed stiffness.
- Choose a softer poly
- Drop tension
- Increase string gauge (decrease string diameter)
- Reduce string-string friction, increase string-ball friction
- Get a new racquet (open string pattern, heavy, head-light, flexible frame)
- Hybrid with gut
- Restring often (maybe)
I’ll also briefly mention a few ways not really related to the string-bed to increase comfort.
Let’s get to it.
1. CHOOSE A SOFTER POLY STRING
This one alone can have a huge impact. As I mentioned above, each string material has a given stiffness. This is indicated with an experimentally determined coefficient of stiffness (k) value. As you can probably guess, a stiffer string stiffens the string-bed and a softer string softens it.
In general, poly strings are stiffer than non-poly strings, but there is a big range of k values among poly strings.
Tennis Warehouse University has a few helpful tools to help you compare string stiffness from one string to another and to help you choose a softer poly string:
The string comparison tool is really useful for choosing a new string. You can put your current string in and choose another to compare it to, which will give you an idea of not only the stiffness difference but also the difference in tension maintenance, power (energy return) and spin potential. You can see what the “side effects” of increasing your comfort will be.
Because I’m a huge nerd, I graphed the stiffness values from the String Stiffness Tool to get a visual representation of the stiffness values of gut, nylon and poly strings. I’ve indicated a few popular poly strings on the graph.
From this graph, two main thoughts come to mind:
- There is no overlap between gut and poly stiffness values. Even the stiffest gut is significantly softer than the softest poly. There is overlap between nylon and poly, though, so poly isn’t necessarily stiffer than nylon.
- There’s a big range of stiffness values for the poly strings. Calling poly strings “stiff” across the board isn’t all that accurate, unless you’re just comparing them with natural gut.
Take a look at where your current string lies on the stiffness spectrum and consider choosing one that’s on the lower end to get more comfort.
2. DROP TENSION
The tighter a string is stretched in a racquet, the more force it takes to stretch it further. Lowering the tension of the strings makes it easier to stretch and deform the string-bed, thus making it softer.
Poly strings have been given a bad rap comfort-wise largely because people are applying the rules of stringing gut and nylon to stringing poly. They’re stringing poly in the high fifties and sixties and then wondering why their arms hurt.
But, according to the article at Guts and Glory Tennis, The Definitive Guide to Stringing Polys and Co-polys, poly needs to be strung lower than nylon and gut to see it’s benefits anyway, and it will be more comfortable if strung low. So playing with poly at high tensions is unnecessarily uncomfortable. A quote from the article:
…Perhaps the biggest obstacle to overcome, is to realize that poly-based strings are designed to perform best at lower tensions. We are talking a tension range in the 30’s – 40’s. The absolute top end of that range would be 52 pounds. Once you go beyond 52, you are entering the point of quickly diminishing returns.
HOW LOW TO GO?
If you’re stringing your poly in the fifties or sixties and finding it uncomfortable, lowering the tension will undoubtedly make your string-bed softer, and more comfortable.
You’ll have to experiment for yourself. Just try dropping a few pounds at a time and see what you think, both in terms of comfort and performance. At some point your strings might start to feel mushy. Poly strings that are too loose will actually provide less spin (according to Crawford Lindsey at TWU in the article, Spin and String Stiffness).
At the beginning of this season I was playing with a full bed of Volkl Cyclone at 48 lbs, which I have typically found comfortable enough. However, I did have some minor hand pain early this year, so was looking for something a little softer. At this point I started experimenting with gut/poly hybrids (more on this in a bit), but then decided to try dropping the tension in my poly strings instead.
I also came across this G> article, Varying Tension on Cross Strings, which says that having the mains strung higher than the crosses allows the crosses to support the mains and extends their tension retention.
So I’ve now dropped my tension to 42/46 (this means 42 lbs in the mains and 46 lbs in the crosses). I find that I still have control, the strings are just as comfortable as the gut/poly hybrids I tried, and as an added bonus I’m hitting with more power (which was something I was looking for).
3. INCREASE GAUGE (decrease string diameter)
A thinner (higher gauge) string is easier to stretch. A string-bed made up of thinner strings will be softer and more comfortable. Most strings come in multiple gauges.
Confusingly, gauge and diameter of a string are inverse to one another. A higher gauge string is thinner than a lower gauge string.
If you’re using a 15 or 16 gauge string, you can soften your bed by switching to a 17-19 gauge. An “L” after the gauge number stands for “light” and is a half-size up (thinner) than the number. So 16L is between 16 and 17 gauge.
Gauges are not standard across strings. A 16 gauge string from one brand will not necessarily have the same diameter as a 16 gauge string from another brand. Just keep this in mind when switching brands of strings and remember that you might need to experiment to find the right gauge for you.
4. REDUCE STRING-STRING FRICTION AND INCREASE STRING-BALL FRICTION
Inter-string forces exist at the intersections of the mains and crosses. When the ball hits the strings these forces resist movement of the strings. Reducing these forces, and allowing the strings to slide more easily against one another makes the string-bed easer to deform and therefore softer.
There are also friction forces between the ball and the strings. If the ball can “grab” the strings more easily, then the strings will move more easily and the string-bed will be more comfortable.
So for a more comfortable string-bed we want low string-string friction and high string-ball friction, which will maximize string movement during impact.
We don’t really need to look at both of these numbers (which have been measured for us by the experts at Tennis Warehouse University) but rather at the ratio of the two COFs (Coefficients of Friction). TWU calls this ratio (string-ball COF : string-string COF) the “spin potential” since a high ratio lets the strings move more easily and thus impart more torque on the ball (read more in the TWU article, How String-To-Ball Friction Affects Spin).
I’ve never come across anything about spin potential in relation to comfort, but it makes sense (theoretically, anyways) that a higher ratio will also mean a more comfortable string since the strings move more easily when contacted by the ball.
TWU has various tools where you can see the spin potential and the friction coefficients for a huge number of strings.
I’m not sure how significant the effects of friction are when it comes to comfort, but to me, every little bit can help, so I think it makes sense to choose strings that will move easily in the bed when hitting the ball, and choosing a string with a high spin potential should help do this.
5. Get a new racquet (open string pattern, heavy, head-light, flexible frame)
Take a look at your racquet specs and see if it’s designed for comfort. If you’re playing with a stiff, light frame with a closed string pattern, switching to a more comfortable frame and pattern could make enough of a difference to let you play with poly pain-free.
I’ve written about this before in my post about managing my wrist pain. I’ll just repeat what I said in that post regarding racquet specs and then go into the string pattern a little more since this post is focused on strings.
- Flexibility/Stiffness: Low RDC index means more flexible and comfortable. Look for a racquet with an RDC in the low 60s or lower.
- Weight: Heavier racquets transmit less energy into the arm, so heavier is better.
- Balance: You want more weight distributed in the handle, or a head-light balance. HH stands for head-heavy and HL stands for head-light. These are typically measured in points, where each point represents a 1/8th inch difference between the racquet’s balance and its midpoint. This can be adjusted after-market using lead tape.
- Beam profile: A thinner beam is typically more flexible and more comfortable.
- Head Size: Larger head sizes can result in more off-centre hits which torque the racquet more and place more stress on the arm. So a smaller head size is usually better.
- Racquet Length: Stick with the standard 27” rather than going longer. I think that this would be because a longer lever arm (distance between where force is applied (ball) and where torque is experienced (hand)) increases torque. Minimize this with a shorter racquet.
- String Pattern: An open string pattern allows more movement in the strings and thus more energy absorption from the ball. An open string pattern should be more comfortable.
Open string pattern:
The string pattern dictates how many main and cross strings you have in your racquet. An open pattern string has fewer strings and wider spaces between them. A closed pattern is the opposite. Open pattern string-beds allow the strings to move more easily and are thus more comfortable. This is because there are fewer string-string intersections and thus less force holding the strings together.
String patterns are indicated by two numbers: the number of mains and then the number of crosses. The lower the numbers, the more open the pattern.
A typical open pattern might be 16/18 or 16/19, while a typical closed might be 18/20.
My racquet is an “Extreme String Pattern” (this is what Prince calls it) at 16/16.
6. HYBRID WITH GUT
This one needs mentioning since adding gut to your setup can definitely make the strings more comfortable, but I’ll also say that, at least in my experience, gut/poly or poly/gut hybrids aren’t very practical for most recreational players.
What’s a hybrid and why do it?
Hybrid stringing just means that the mains and crosses are different string materials.
Poly strings are typically mixed with gut in hybrids, but not always. We’ll focus on this mix, though, since if what we’re looking for is comfort that’s what we’d probably do.
The naming convention for hybrids is to say the main string first. So a poly/gut hybrid has poly in the mains and gut in the crosses.
There’s a lot of debate between which hybrid is better: gut/poly or poly/gut. I’ve tried both.
I’ve read before that about 80% of the string performance comes from the mains. So if you want your racquet to play more like poly you put poly in the mains and vice versa for a racquet that plays more like gut.
Here are some of the features of the two setups (based on reading and experience, but feel free to correct me!):
Poly/gut: This setup should play more like a poly setup but be a little more powerful and comfortable, and provide a little less spin. I have found this to be true. I was able to comfortably play with a seriously stiff string (Lux 4G, which I know from experience is very uncomfortable on my wrist in a full-bed) when I put natural gut in the crosses.
Gut/poly: This setup gives some stability to the gut (the stiff poly crosses prevent the gut from stretching as much as it normally would). It should be even more comfortable than the poly/gut if most of the performance is coming from the mains. The gut should also slide a bit better against the poly (particularly if the poly is smooth) which lets it snap back more than it otherwise would and impart more torque (spin) on the ball. This is the setup that Federer uses and he seems to get plenty of spin for having gut in the mains. (A lot of people will point out that Federer could probably get a lot of spin from a full bed of kitchen twine, though, so we should be cautious when taking pointers from him!)
My experience with both of these setups was pretty good, with one major drawback: cost. This is why I don’t think it’s that practical for rec players, or at least for players who like playing with fresh strings.
Poly strings lose tension fast, and natural gut strings are much more expensive than most polys. This probably doesn’t concern Roger too much, but for me, going through a set of gut every week or two at $50+ a set, plus the cost of the poly, just doesn’t make sense.
Even if you don’t mind the tension loss in the polys, a shaped poly will saw through the gut like nobody’s business. When I strung with my Volkl Cyclones in the mains (shaped poly) and gut in the crosses I got 3 hours of play before the gut broke. This didn’t happen with the smooth Lux 4G strings though.
Also, I have heard that some people will cut out the poly crosses and just re-string them, keeping the gut mains in the racquet for much longer. I haven’t tried this method myself, but it would save on stringing costs. Make sure to only cut the strings once your racquet is securely mounted on your stringing machine if you try this to avoid warping your frame.
For awhile I thought about trying to make a gut/poly hybrid work. It was comfortable, but I definitely noticed less spin, which I didn’t like. And it was expensive.
And honestly by adjusting the other variables in my setup I’ve found I can get just as much comfort from a full bed of poly, so for me, there’s no reason to hybridize.
7. RESTRING OFTEN (MAYBE)
Two key points on tension loss and comfort:
- According to the lengthy article at TWU, How Tennis Strings “Go Dead” — Part 1, there are competing effects of strings losing tension over time on the string performance. The net effect will dictate whether the string-bed is softer or stiffer, and therefore more or less comfortable. The variables include string stiffness, tension and friction forces.
- Regardless of whether your strings become technically more or less comfortable, other performance changes with time can cause you to change your technique. This can lead to discomfort, which is often attributed to the strings but might in face be caused by the technique change.
I personally find that fresh strings are more comfortable than old strings, but this could definitely be because I swing differently when my strings get old. I find that I gain power and lose control as my strings get older, which I think causes me to swing faster and steeper (to get more spin) and I subconsciously hold the racquet tighter (to get more control).
You need to see what works for you here. If you’re finding that your strings become more comfortable with time, this could indicate that you’re stringing your racquet too tight to begin with. As your tension drops with time you get into a more comfortable zone. Consider dropping tension, and you might find your racquet is comfortable from the get-go.
If you’re finding your arm pain worsens with string use, just re-string more frequently.
I like restringing frequently for performance reasons anyways – there are enough variables in tennis without ever-changing equipment to contend with – so I like to string at a comfortable tension to begin with, and then restring when it gets too low.
ADDITIONAL WAYS TO DECREASE ARM PAIN
Here are a few other ways to help reduce shock on your hand, wrist and arm that don’t really have much to do with string-bed stiffness:
- Use a vibration dampener
- Use fresh, soft balls (I personally find the Penn ATPs and Wilson US Opens much softer than Penn Marathons. And balls get stiffer as they get older.
- Warm up, particularly in cold weather.
- Realize your body and equipment will be stiffer in cold weather. Consider dropping tension further when it’s cold, wearing extra clothing or even a compression sleeve to keep you muscles warm, and don’t store your racquet or equipment in your car or garage but try to keep them warm.
To recap, anything we can do to soften our string-beds will help make them more comfortable. Methods for softening the string-bed include:
- Choosing a softer poly
- Dropping tension
- Increasing gauge (decreasing string diameter)
- Reducing string-string friction, increasing string-ball friction
- Changing racquet specs (open string pattern, heavy, head-light, flexible frame)
- Hybridizing with gut
- Restringing often (maybe)
And we can keep the following tips in mind that should also help minimize arm and wrist pain:
- Use new, soft balls
- Use a dampener
- Warm up
- Be careful in cold weather
I hope this is helpful information for people who want to use poly strings but have trouble with arm or wrist pain. I’m not suggesting that making your setup more comfortable is a quick-fix for long term issues like wrist tendinosis or tennis elbow, but taking the above measures will certainly help reduce shock on your arm and wrist, and this can be great for both reducing existing pain and preventing problems from happening in the first place.
And, from what I’ve read and in my personal experience, softening your poly string-bed maximizes the performance of poly strings. These strings are not meant to stay in place in your racquet, but are meant to stretch and snap-back, which imparts the spin on the ball that poly is notorious for.
So in my opinion, taking measures to soften our string-beds and allow easy string movement allows us to reap the benefits of poly without paying the price of pain.
Let me know if you have any questions or comments. As always, I’m doing this to learn so would love to hear if you disagree with any of this or have any other suggestions for making poly setups more comfortable!