Strings (tennis)

In tennis, the strings are an important part of a tennis racquet. They are the part of the racquet that hits the ball during play. The strings form a woven network inside the head, or “hoop,” of the racquet.

Strings can be made from many different materials, and each type has special qualities. These qualities include how stiff the string is, how well it keeps its tension, its thickness, its texture, and how well it helps the ball bounce back after being hit. These features can change how the racquet feels and performs for the player.

Composition

The material used in tennis strings can change how well a player does. There are many kinds of materials used to make tennis strings. These materials differ in how stretchy they are, how long they last, how well they keep their tension, and how much they cost.

Natural gut

Animal intestine is the strongest material used for tennis strings. It keeps its tension better than any other material and is softer too. This means it gives the most power when hitting the ball. It stays soft even when tightly strung, which helps players control the ball better without losing power or feeling too much impact on their arms.

However, natural gut costs more to make and buy than other materials. It can also be weaker when the ball hits the strings off-center, especially for new players. The quality can vary a lot depending on the brand, how old it is, and how it’s stored. It is also harder to string because it is delicate and doesn’t last long when it gets wet. Players who use natural gut often carry several rackets with different tension levels to adjust for weather changes.

Synthetic gut

Synthetic gut is usually made from nylon and is the cheapest kind of string to make and buy. Sometimes small changes are made to nylon, like adding texture, color, or a little bit of Kevlar. Some companies call nylon strings “synthetic gut” even though they don’t contain any real gut.

Multi-filament, or "multi"

Multi-filament strings have more than one filament, or thin strand. They are often made from nylon but can include other materials like polyurethane, Zyex, Vectran, and Kevlar. These strings are more stretchy than single-strand strings but usually don’t last as long or keep their tension as well as natural gut. However, they come closer to the performance of natural gut than single-strand nylon strings.

Nylon

Nylon is the most popular string for amateur players because it is cheap and multi-filament nylon strings are more stretchy. Nylon strings often have special coatings to help them last longer, especially the outer strands that tend to break first.

Polyester

Polyester is a strong and lasting string material, first made for players who broke strings often. It didn’t become popular right away because it didn’t hold tension well. But players found they could put more spin on the ball while still controlling it with polyester strings.

Polyester became very popular in professional tennis when a Belgian string maker gave it to Gustavo Kuerten in 1997, and he won the French Open that year. Since then, polyester has been the most used string in professional tennis because it helps players create heavy spin. Experiments have shown that polyester strings increase spin, possibly because the strings don’t grip each other as much.

Kevlar

Kevlar is the stiffest and most durable synthetic string, making it very hard to break. However, it can be hard on the arm and cause tennis elbow. It is often mixed with another string, like nylon, to make it more comfortable. Some players use a very thin Kevlar string to feel more comfortable, and others string it at a lower tension to reduce stiffness.

Vectran

Vectran is the second-stiffest and most durable string type but is not used very often. It is usually added to nylon strings to make them stronger and stiffer, similar to Kevlar. Some companies make tennis strings from braided Vectran.

Zyex

Zyex strings give more power and feel softer than other synthetic strings, especially when strung at lower tensions. This makes them play more like natural gut. However, the outer materials of Zyex strings don’t last as long and can wear away, leaving the inner Zyex strands exposed.

Polyolefin

Polyolefin is one of the softest synthetic strings, almost as soft as some Zyex and nylon multi-filament strings. It doesn’t last very long or hold tension well, so it is usually used only for the cross strings in a hybrid setup. For players who don’t break strings often, using only polyolefin strings can be a good choice, especially if they have tennis elbow and find natural gut too expensive.

Metal wire

In the past, some racquets used metal wire, often piano wire, for their strings.

Titanium

Titanium is also used in strings. It is usually added to nylon or multi-filament strings either as a coating to protect against UV light and wear, or mixed into the filaments to change how the string feels when playing. Titanium strings are not popular today.

Catgut Shear stresses Fibers Cow Intestine Serous membrane Collagen Sheep Babolat Nylon Polyurethane Vectran Kevlar Polyester Gustavo Kuerten Tennis elbow Yonex ProKennex Polyolefin Titanium

Gauge

The "gauge" number tells us how thick the tennis string is. A higher gauge number means the string is thinner, while a lower number means it is thicker. Thinner strings can give better performance but they may break more often than thicker strings.

Stringing pattern

Most modern tennis racquets have strings arranged in a criss-cross pattern, going horizontally and vertically. In the past, other patterns were tried with different results.

In 1977, double strung racquets called "spaghetti racquets" were introduced but later banned because they gave too much spin and an unfair advantage.

Racquets can be strung with two separate strings, needing four knots, or with one string, needing only two knots. Sometimes, two different types of string are used together in the same racquet. Traditionally, a special double half hitch and a starting knot were used to finish the strings. Newer knots like the "pro-knot" and "Parnell knot" are now used, sometimes with a clamp to make all knots look the same.

Stringing

Main article: Stringing machine

Stringing is the process of putting strings into a tennis racquet. This is done using a special machine called a racquet string machine. These machines can be simple or very advanced, and their prices can vary a lot.

String tension

The string tension of a racquet shows how tight the strings are, usually measured in pounds. This tightness changes how the racquet feels and works when hitting the ball. It can affect how much control you have and how powerful your shots are.

Racquets usually have a suggested tension between 50 and 70 pounds. A looser string gives a bigger sweet spot and can send the ball farther, but might make shots less predictable. Tighter strings help with control and making softer shots, but can make it harder to feel the ball. Players often start with the middle tension and adjust based on what feels best.

Restringing

When strings are put in a tennis racquet, they start to lose their stretch and tightness right away. Strings that have lost their tightness, called “dead strings,” can make it harder to play well. They might also make it tough to hit the ball hard or fast, and could even hurt a player’s arm.

How often a racquet needs new strings depends on how much someone plays. One rule is to change the strings as many times a year as the player uses the racquet each week. For example, if someone plays three times a week, they should change the strings three times a year. Another rule is to change them after about 40 hours of playing. If a player uses the racquet three times a week for three hours each time, they should change the strings about every five weeks. Some players check how tight the strings are and change them when they feel they’ve lost a lot of their tightness. But many players just change their strings when the old ones break.

United States Racquet Stringers Association

The United States Racquet Stringers Association (USRSA) gives out two levels of certification for people who string tennis racquets: Certified Stringer and Master Racquet Technician. There are about 350 Master Racquet Technicians around the world. To become a Master Racquet Technician, a person must show they can string a racquet, fix the grip, spot problems in a racquet that is strung wrong, and pass a written test about racquet technology.

Since 2004, the USRSA’s monthly magazine, RSi, has picked a Stringer of the Year. Some past winners include:

• Randy Stephenson, Texas (2004)
• Bob Patterson, Alabama (2005)
• Grant Napier, Tennessee (2006)
• Tim Strawn, Virginia (2007)
• Nate Ferguson, Florida (2008)
• Ron Rochi, Illinois (2009)
• Tom Parry, Minnesota (2010)
• Todd Mobley, Georgia (2011)
• John Gugel, Florida (2012)
• Chuck Hakansson, Georgia (2013)
• David Yamane, North Carolina (2014)
• Julian Li, California (2015)
• Philip van Asselt, Pennsylvania (2016)