| By Fritz Buehning

Let me go on record … I think every package of polyester string needs to come with this warning label due to improper usage by the general public. Is this a pretty bold statement? I believe so. Why is it a bold statement? In my opinion, the improper use of polyester string is responsible for the bulk of tennis-related arm injuries. I hear about more arm injuries now than ever before—wrist, shoulder and elbow (tennis elbow and the newer golfer’s elbow). Since I predominantly work with children, I’m talking about, not just nagging, but potentially long-term serious and damaging injuries to your children. Do I dislike polyester? Not necessarily. Do I think it should be used by children? In general, no … and by children, I mean 95 percent or more of kids that are age 14 and younger. I do not believe that many of these kids really can tell or know when the poly string needs to be replaced, namely, when their strings are dead. Dead strings mean they have lost their elasticity or resiliency and tension. Remember, just because they don’t “break” doesn’t mean they are still good! Why am I passionate about this? Because for the last few years, I am seeing and hearing about arm issues, and in almost every case, the player or parent does not understand the nuances and dangers of playing with poly strings.

Most people know that there are a wide variety of string manufacturers with hundreds of different types of string on the market, all claiming theirs is the best, the most durable, creates the most spin and now is the softest, from the names we know like Luxilon, Wilson, Technifibre, Dunlop, Solinco, Head, Babolat, Mantis, Prince, Donnay, etc. 

Tennis strings fall into five categories:

►Natural Gut: The most expensive type of string that used to be the string of choice for the vast majority of the pros before polyester was developed. It holds tension well and is considered the softest of all the strings.

►Nylons: Generally known as “synthetic gut” and “multi-filaments.” These are considered comfort strings, not as soft as gut, but these strings fray and then break before they go dead. They were designed as a cheaper solution to Natural Gut. Most hold tension well and have been around for many years.

►Polyester: Generally considered durable strings. A newer technology that has gained in popularity over the last five to 10 years in the U.S. and worldwide, the poly is the choice for many pros due to its ability to produce extra power and spin. However, Poly is also considered a stiffer type of string.

There are two other lesser used and known types of strings. Aramid (Kevlar), which is more durable than polyester, however, in my opinion, I don’t want to be hitting tennis balls with a material that stops bullets. Another is, Zyex, a newer product I am not yet familiar with.

My first experience with polyester string was about six years ago. My son was given some free packs of “great, new string” out at the U.S. Open. We strung up one of his racquets with it, and after two to three hours of play, our balls started flying. The string and racquet looked fine, so how can strings go dead after two to three hours? I spoke to the manufacturer’s rep, and it turned out that this was the first generation of poly strings, and he told me to just re-string the racquet! While the strings played well, it made no sense to me to use them if I would only have to cut them out and restring after just a couple hours of play.

Fast-forward a couple of years … my teenage son who now lives and plays in Florida, started mentioning some shoulder pain. I found out he had switched to using poly strings for “durability” (he was tired of the restringing costs). I knew he was leaving them in the racquet too long, that they were “dead,” and he admitted to leaving them in far too long, sometimes up to two months while playing around three hours per day. I wanted more specific info on these strings, so I turned to my stringer, Larry Hackney. Larry has a small tennis shop in New Jersey, is a certified master stringer, and suffice it to say that Larry knows more about string than anyone else I know. I started to pick Larry’s brain and listened more attentively to the nuances of polyester strings, in particular, the specs, playing life, his reviews and play tests of particular poly strings.

After several conversations with my son, he agreed to rest his arm and go back to playing with a multifilament string. Shoulder problem resolved. Interestingly enough, a couple of months later, he reported that he attended a seminar with some racquet and string customization experts and guess what? All the info that I gave him about poly was 100 percent on point … guess dad does know what he’s talking about!

How do we know if we’re potentially injured? Well, it usually hurts and there is pain! And the “hurt” is different from the muscle fatigue we feel from a good workout, where something is “aching.” So why am I so concerned about potential injuries? I’m the guy whose pro career was cut short at age 27 by playing on an injured foot for six months before having it looked at. I failed to recognize the difference between “ache” and “pain.” I see it almost every day, children in pain on the tennis court, forced to determine whether they can “play through” the pain of some minor injury. In my case, it turned out to be a career-ending injury so when it comes to the pain of any injury—me, you, my kid, your kid—I prefer to err on the safe side rather than the sorry side.

The most important thing I have learned and you should know is that polyester has a “playing life” in your racquet. Although we are now in who knows what generation of polyester strings—the life of any particular poly string falls between four and 20 hours—depending on different factors. Another fact is that polyester string will lose tension, even if the racquet is not being used. So think of it like a cell phone battery … there is “life” and “talk life.”

But let’s remember there is also the elasticity and resiliency issue. What happens when poly string loses its elasticity? The strings become elongated and reach their elasticity threshold, become hard, and to your arm, it’s like hitting the ball with a board. Unfortunately, visually, the strings look the same, but your arm is now absorbing more of the impact. Injuries now may occur because the player has to swing harder to achieve the same amount of power and spin that they are used to generating with fresh strings. With the string life over, the player must now cut out the strings and restring their racket. Top junior players (16U) will break their poly before it goes dead, but for most of the younger kids, they don’t hit hard enough to break them!

There is no doubt that polyester strings have hugely impacted the pro game. The amount of power and spin players can now generate is unprecedented. So why do all the kids want to use a poly string? Because the pros use it. The polyester string was designed for professional players. Initially made popular by clay courters because of the clay “grit” that also adhered to strings and added to strings being broken, pros wanted something more durable. To a pro, durability means playing for nine games or a full set or one to three hours in practice.

Remember, pros use multiple racquets during a match and will freshly string six or more racquets before they walk out on the court. On top of that, the top pros will cut out all their strings from all their racquets–used and unused–after each match. Pros correctly understand and use the technology. In this case, durable does not mean forever or until it breaks.

Polyester is considered, and quite frankly is, a “stiffer” type of string, which is tough on the arm to begin with. Now we hear the manufacturers are coming out with “softer” polyesters. Are they developing better and “softer” poly? Yes. Have they significantly improved playing life? No. Do I think it still needs a warning label? Yes. Do I think there is a correlation between the use of poly and more arm injuries? Yes. And what I find most disturbing of all–when you purchase certain 25-inch or 26-inch junior racquets, they come pre-strung from the manufacturer with poly! I don’t even know how you attempt to justify this practice! Reality check … how often do most kids under the age of 11 break strings? Since we don’t know how long a racquet has been sitting in a warehouse or on a shelf, it’s very possible you’re already giving you’re a kid a racquet with dead strings. Please, check your child’s racquet and restring immediately if it has poly!

In the July 2012 issue of Racquet Sports Industry magazine, there is an editorial entitled “We Need a ‘Restring’ Campaign” by Editorial Director Peter Fancesconi. Although he doesn’t mention any types of strings specifically, reading between the lines, I think he’s talking about polyester when he states, “We need to make sure consumers know they should restring their racquets more frequently” and “Playing with dead strings may actually hurt the player too.” Interestingly, in the same issue, there is an interview and Q&A with Lucien Nogues, one of Babolat’s top stringing experts where he discusses the necessity of changing strings more often and that pros are stringing at lower tensions. And my personal favorite snippet in the Industry News was an ad for new orthopedic braces being developed for sports injuries, including a photo for a new elbow brace!

I have used gut, full polyester, various hybrids of poly/multifilament, synthetic gut and multifilament. What do I use? I use a 16-gauge full multifilament that holds tension well, frays like gut, is easy on my arm and breaks before the strings go dead. My string of choice is Technifibre NRG2.

What do I suggest you do? Educate yourself. Do your due diligence when your kid asks for the latest and greatest strings. Find a certified master stringer who keeps abreast of the industry, pick their brain, and then string accordingly. And watch the TENSION! Did you know it is recommended to string poly at least 10 percent lower than a multi or gut? Did you know that humidity and temperature can impact your string? So don’t leave it in the car or trunk, especially during the winter or summer. Did I mention that strings lose tension even if they sit in your closet? If you are breaking strings too frequently, try a thicker gauge string or a hybrid stringing configuration. Still want to use full poly? Then track both the number of playing hours and the amount of time that the racquet has been “strung.” Get the string checked by a certified master stringer if you are not sure and cut out appropriately. And if your child’s arm starts bothering them, ice, rest, change to either natural gut, multifilament or synthetic gut strings. If the pain becomes worse, see an orthopedist before any real damage can happen … its better to be safe than to be sorry!

Lastly, let’s get after those string manufacturers to add a warning label, tell us about string “life” specifications and give us stiffness info on their strings. To me, it’s a win-win situation—good for the player’s health and with players restringing more often, it creates more of a demand for string from the manufacturers!