The String Theory posits that all objects in the universe are composed of vibrating filaments, or strings, and membranes of energy. Called the “Theory of Everything,” one day it will unlock one of the biggest mysteries of the universe: how on earth can I hit the ball harder and still make the darn thing stay in the court?

If physics string theory is complex, tennis string theory can be absolutely confounding. In fact, a few years ago a doctoral student at the University of Cambridge in England amassed mountains of data studying how the ball strikes the racquet. His conclusion?

“We don’t understand how the ball interacts with racquet strings,” he said.

If doctoral candidates can’t unlock the conundrum of the String Theory, how can the average recreational player? Which string gives the best game? Gut or synthetic blend? Synthetic gut? High tension or low? Vibration dampener or not?

Veteran racquet stringer Craig Willeford, of Brotman Racquet Design, who’s been tending to the players’ racquets at this week’s BMW Tennis Championship in Sunrise, FL, sat down to explain the development of the Tennis String Theory.

Early pro players used natural strings called “catgut,” which was actually cow, not cat, intestines, Willeford explained. This was good news for ailurophiles, as it takes six cows to provide the forty feet of gut needed to string one racquet. One can only imagine how many kitties it would take to fill a Prince.

In the late 1970s, “spaghetti” stringing briefly burst onto the tennis circuit. An innovation featuring non-intersecting strings on independent planes, with players throwing different fibers, wires and even rubber bands into their racquets, a spaghetti-strung racquet bit the ball and created more revolutions, imparting greater spin and unpredictable bounce. In 1977, Ilie Nastase played Guillermo Vilas with a spaghetti-strung racquet. The ball bounced so wildly that Vilas quit in disgust, and the International Tennis Federation banned spaghetti strings the following year.

Andre Agassi, an eight-time Grand Slam champion, was the first professional to use Kevlar, a stiff polyester that’s used in bulletproof vests, in the mid-1990s. His success popularized polyester strings on neighborhood hardcourts as much as on the pro tour.

Despite the growing popularity of synthetic strings, many elite players still played with gut as late as 2004. The latest innovation is the synthetic-blend string, a plastic polymer shaped into string form, which has been called the single biggest development in tennis, greater even than Rafael Nadal’s capri pants.

Willeford said that close to 80 percent of the players in the BMW Tennis Championship opt for Luxilon ALU Power, a synthetic blend that enables them to swing with great power yet keep the ball in the court. The stiffer the strings, the less the string bed will deflect, imparting a more precise angle and a truer ball strike.

“Stiff polyester allows the players to swing for the fences while keeping the ball in the court,” Willeford said. “The ‘dead’ feel allows the players to plow through the ball.”

The current generation of professionals is much bigger and stronger than their predecessors. For example, both Daniel Brands and John McEnroe were at last month’s Delray Beach International Tennis Championships. Brands is a rising 22-year-old German who, at 6’5”, 203 lbs, towered over the 5’11”, 165-lb McEnroe.

“Brands looks like he can eat McEnroe,” Willeford said.

And it’s the greater size and strength of today’s tennis professionals that drive changes in string technology. As players get bigger and stronger, string manufacturers develop products to help them take full advantage of their ball-crushing, high-velocity swings.

Willeford cautioned that recreational players should not rush out to restring with polyester.

“The new technology is of no benefit to the average recreational player,” he said, as weekend duffers lack the swing speed needed to take full advantage of stiff strings.

Another problem with recreational players using the new technology is expense. Willeford pointed out that polyester strings have to be changed weekly, whether they’ve been played on or not.

And perhaps the most worrisome aspect for non-professionals is that polyester strings can lose tension within 24 hours. With string tension loss, the arm has to work harder, which can cause tennis elbow and shoulder tendinitis.

Willeford recommends that recreational players opt for synthetic gut instead.

Racquets is the one area where recreational players can put pros to technological shame.

“The average recreational player can buy more technologically advanced racquets than the pros use,” Willeford said. “Pros’ racquet models can be 10 to 15 years old -- they don’t switch a whole lot. If they’re having success, they don’t change. It is their livelihood.”

As for tension, the current trend is to go low. Willeford pointed out that Monica Seles, for example, preferred high tension, stringing her racquets in the 70-pound range; most players at the BMW Tennis Championship, by contrast, string their racquets only in the mid-40-pound range. The lower the tension, the longer the ball stays on the racquet.

“The longer the ball stays on the strings, the more you can do with it,” he said.

And as for the last question, to dampen or not to dampen?

Willeford said that the pros tend not to use vibration dampeners. The rubber dampens string vibration, but also mutes sound, and elite players rely on hearing the precise tone of the ball striking their strings.

So, if you want to play like a pro, pump up the volume.

Story by Amy Roth, BMW Tennis Media Staff
March 20, 2010