Strings may be the soul of racquet, but to many players they are just an afterthought. Players will spend months demoing racquets yet only minutes choosing a string, the very thing which makes contact with the ball and greatly determines what the player feels. Fortunately, the non-gut synthetic string universe (mostly nylon and poly based) has improved dramatically over the last few decades. Today, there is so much diversity in the string market that any player, with a little research, can zero-in on a desired feature set. Here are a few guidelines to make your string and tension selection easier.

Playability

It's very difficult to obtain consensus on what makes a string playable. Some players like a crisp, firm playing string while others equate playability with softness and comfort. Historically, a playable string is one that is gut-like in its feel and resilience. Natural gut is the only string made from a natural product, thin ribbons made from beef intestines, which, when twisted into a tennis string, create a comfortably crisp feel that is simply unmatched. Natural Gut is the oldest tennis string and remains the benchmark for playability. While no other string material can quite match the sublime feel and response of natural gut, Tennis Warehouse offers many synthetic strings that have phenomenal playability: Babolat X-Cel, Dunlop Silk, Gamma Professional, Prince Premier Power, Tecnifibre NRG2, Tecnifibre X-One Bi-Phase and Wilson NXT. Strings that offer good playability at a lower price (below $8.00) include: Alpha Gut 2000, Head RIP Control, Head FiberGEL Power, and Tecnifibre E-Matrix (TW Exclusive).

Durability

As with our beer, most of us want a string that offers everything. Unfortunately, increased durability in tennis strings is usually at the expense of playability, especially on shorter strokes which feel stiff and dead. Thicker gauges and abrasion resistant materials will be more durable, but they are less elastic and resilient than their thinner counterparts. (See gauge table below.) If a player is breaking a 16 gauge nylon string (synthetic gut), we might suggest they switch to a 15L version of that same string, if available. For the multifilament player (who needs a softer feel), Prince has some "comfort strings" in thicker gauges, like Premier Touch 15L and Premier Control 15 . Otherwise, the next step would be a nylon durability string, such as Gosen AK Pro CX, Gamma Marathon DPC or Wilson Synthetic DuraMax. After that, we recommend trying a polyester hybrid like Volkl Psycho. If you're sawing through your crosses, we recommend a full stringbed of polyester where you can select a firm one like Kirschbaum Super Smash or a softer one like Polyfibre TCS. Finally, for the advanced (5.0+) player who blows through the strings listed above, we suggest a Kevlarhybrid, which is the end of the road for chronic string breakers. Proceed with caution as Kevlar sends a lot of shock to the tendons.

String Gauge

Generally speaking, thinner strings offer improved playability while thicker strings offer enhanced durability. Tennis string gauges range from 15 (thickest) to 19 (thinnest), with half-gauges identified with an L (15L, 16L, etc), which is short for "light". A 15L string is thinner than a 15 gauge but thicker than a 16 gauge string. Thinner strings also provide more spin potential by allowing the strings to embed into the ball more.

String Gauges and Diameters in millimeters

15=1.41-1.49 mm17=1.20-1.24 mm

15L=1.34-1.40 mm17L=1.16-1.20 mm

16=1.26-1.33 mm18=1.10-1.16 mm

16L=1.22-1.26 mm19=1.00-1.10 mm

Materials

Nylon - synthetic gut or nylon? Truth be told, most synthetic guts are made with nylon (sometimes referred to as polyamides). There are different grades of nylon, with varying levels of feel, so don't be afraid to try different synthetic guts until you find the right fit. All in all, synthetic gut delivers a good combination of playability and durability at a great price. In the old days (wood racquet era), any self-respecting player used natural gut. Today, an impressive number of non-professional players use nylon-based strings, which have greatly improved in the feel department. In fact, Nylon multifilaments offer truly impressive comfort and power. Unlike the more basic synthetic guts (which have a single, solid core), multifilaments are comprised of hundreds or thousands of ultra pliable, elbow-friendly fibers, and bundled together with flexible resins like polyurethane. Other string materials include:

Natural Gut - the ultimate in playability, feel and tension maintenance. Often overlooked due to it's cost, natural gut is the best choice for players with arm problems or those who crave its sublime, comfortably crisp feel. Formerly, the number one choice of ATP and WTA tour players. Now used more in hybrids, combining polyester mains with natural gut crosses (with some players using gut in the mains for more power and feel). Natural gut offers maximum feel and control due to its ultra low stiffness, which provides phenomenal ball "pocketing".

Polyester- a very durable string designed to provide control and durability to players with long, fast strokes. Polyester is the number one choice on the pro tour because it allows advanced ball strikers to maintain surgical control on their fastest, most aggressive strokes. The incredible stroke speed enabled by polyester also translated into categorically higher level of spin, which literally changed the trajectories and angles available to the player. Polyester also served to harness the immense power that came with graphite era. While it used to be too stiff and dead for recreational players, a growing number of string manufacturers have devoted the lion's share of their R&D to creating softer, more elastic polys so that a wider cross section of players can enjoy its benefits. Another way to get the benefits of polyester is through a hybrid, also very popular on the pro tour. This is typically done by combining polyester (usually in the mains) with natural gut or multifilament crosses. This setup provides the durability, control and spin of polyester with the comfort, power and touch of a softer string - otherwise known as the best of both worlds. Due to its high stiffness and relatively low power, polyester is not recommended for beginners or players with arm injuries.

Kevlar - The most durable string available. Kevlar is very stiff and strings up very tight. Therefore, it is usually combined with a soft nylon cross to reduce stringbed stiffness. Ultimately, Kevlar hybrids are the least powerful and least comfortable strings currently available. Players trying kevlar hybrids for the first time (from nylon strings) are recommended to reduce tension by 10% to compensate for the added stiffness. Not recommended for beginners or players with arm injuries.

Work Cited:  “All About Strings & Stringing.” Essential Shoulder Exercises for Tennis Players, www.tennis-warehouse.com/LC/StringReference.html.