Howard Brody examines some of the world`s strangest tennis rackets in his laboratory at the University of Pennsylvania. One comes complete with a pump used to inflate an inner tube around its strings. Another contains a knob on its handle that tunes the strings like a violin. Still others have hinged handles and hexagonal-shaped heads.
Brody, a Penn physics professor, has spent thousands of hours in his lab during the last 10 years studying these and other bizarre rackets. Using lasers, oscilloscopes and other scientific paraphernalia, he has spent more time analyzing the physics of tennis than perhaps any other scientist.
As a result of his studies, published in prestigious physics journals, he has overthrown long-held assumptions about the best ways to play the game. He has also written two books on the science of tennis, appeared on radio and television shows and given more than 50 lectures to physicists and tennis coaches.
”If I had spent as much time on the courts as I`ve spent in the lab, I`d be a great player,” he says with a chuckle.
Brody is one of a small but growing number of physicists, biologists and engineers who are using the tools of modern science to improve the
performances of this nation`s athletes.
As the nation turned its attention to the Summer Olympics, these men and women were using new knowledge about equipment, nutrition and the body`s abilities to help athletes run faster, jump higher and compete more successfully in sports ranging from archery to tennis.
Brody has spent most of his time analyzing tennis, but he has also performed some studies of football, basketball and baseball. After he published a paper that determined the best place on the bat to hit a baseball, he wrote to the Phillies to see if they were interested in his findings.
”It was like falling into a black hole,” he recalls. ”Nothing came back.”
By contrast, tennis players are eager to learn about his findings, which have been published in his book ”Tennis Science for Tennis Players.”
”Tennis players are very intelligent people,” he said. ”They look for any scrap of information that will give them an advantage and help them improve their game.”
Brody, 56, has loved the sport of tennis for almost half a century and played on the varsity tennis team at the Massachusetts Institute of Technology as an undergraduate.
But he has spent the bulk of his career-more than 25 years-studying elementary particles, searching for quarks, mesons and other fundamental building blocks of matter.
Along the way he studied with Murray Gell-Mann and Richard Feynman, who both won Nobel Prizes in physics, and performed experiments at Fermilab, Brookhaven National Laboratory in New York, CERN in Switzerland and most of the other shrines for particle physicists in the world.
”It`s still very exciting when a new particle is discovered,” said Brody, dressed in sneakers, casual trousers and a tennis sweater, as he relaxed in his office not far from Penn`s tennis courts.
”But I got burned out on particle physics. It took four to five years to plan an experiment, four to five years to carry it out and four to five years to analyze the results.”
”No one cared,” he says, of that research. ”But now that I`m analyzing sports, everybody thinks I`m something great.”
Brody first became interested in the physics of sports about 10 years ago when he saw an oversized Prince tennis racket and wondered how it worked. He wrote to the manufacturer and received a personal letter from Howard Head, the man who invented it.
He soon learned that almost nothing was known about the physics of tennis. Equipment was being manufactured on a trial-and-error basis. Few studies had ever been done.
So, using a laser, mirrors and other apparatus, Brody began to determine the underlying principles that govern tennis rackets and winning strategies. He discovered that in addition to skill and talent, vibration nodes and the coefficient of restitution also help a player hit aces and cross-court winners.
Brody determined that rackets actually have three different ”sweet spots”-a term that tennis players use to describe the place on the racket`s strings where it feels ”good” to hit the ball.
He found that one spot, scientifically known as the center of percussion, is the place where there is the least initial shock to the hand. He determined that the second spot, called the node of the first harmonic, is the place where uncomfortable vibrations to your hand and arm are smallest. And he discovered that the place where the ball bounces off the strings with the greatest power has what scientists say is the maximum coefficient of restitution.
The placement of these three different spots varies, depending upon the shape of the racket. In theory, Brody says, the ideal tennis racket would have all three of these points located at the center of the stringed area. In addition, the areas of maximum power and minimum vibrations would cover most of the racket`s face.
Brody, who plays tennis about once a week, has discovered that some conventional wisdom about tennis rackets is all wrong. Contrary to the popular view, for example, he found that tighter strings mean less power and that looser strings mean more power.
He has also discovered that stiffer-not more flexible-rackets give the player the most power. During the past year, many thicker and less flexible rackets have come on the market, although Brody said he did not know whether his findings had influenced the manufacturers.
In the coming years, Brody believes that the biggest breakthroughs in tennis technology will come in improved strings that give balls more zing. He also foresees rackets made with advanced cushioned grips and space-age materials that reduce vibrations.
Also under development are electronic courts that accurately tell if a ball has been hit in or out without a linesman. Tricia Keeler, a spokeswoman for the U.S. Tennis Association, the nation`s governing body for tennis, said that the organization is evaluating 15 different electronic courts that range in price from about $3,000 to $50,000.
While most of these courts are in the development stage, she said that some had already been manufactured by Canadian Tennis Technology Inc., a company based in Sydney, Nova Scotia, and have been installed at Canadian tennis clubs.
Based on his experiments at Penn`s sports laboratory, Brody offers tennis players the following advice:
– A stiff racket will give you more power and control. Lightweight rackets are best for the serve-and-volley game. Medium-weight rackets are best for the player who stays in the backcourt and hits ground strokes.
– On ground strokes, you increase your chance of getting the ball in when you hit the ball at a greater height. Closing in toward the net to volley increases your chances of getting your shot in.
– You improve your chances of getting your serve in when you increase the height at which you hit the ball, increase the topspin on your shot and position yourself closer to the alley.
– Play high percentage tennis. Don`t try to win a point with one shot unless there is a very good chance you will succeed. The winner is usually the player who has made the fewest errors.
– You can`t beat the laws of nature, but you can use those laws to beat an opponent.
