Feature Presentation

It's difficult to pick up a tennis magazine without seeing a reference to the International Tennis Federation's (ITF) Technical Commission or a quote from Andrew Coe. As the head of product development and the technical commission for the ITF, Andrew has been involved in tennis' leading edge research projects for the last 4 years. From the studies which led to the proposed ball size increase, to the development of a machine which will reproduce a man's pro serve, Andrew and commission members must balance technological advancement against preserving the basic nature of the game.

We spoke with Andrew about his work from his office at ITF headquarters in Roehampton, London, England. We started by asking Andrew to tell us about the ITF and the Technical Commission's involvement in tennis research.

"The International Tennis Federation (ITF) is the governing body for world tennis. Countries like the United States have a national governing board - for the US that is the USTA (United States Tennis Association). Similarly there are 201 member nations in the ITF. Although the ITF establishes the rules of the game, each country is responsible for the enforcement of those rules."

"The ITF has separate medical and technical commissions. While the medical commission deals with the sports medicine, physiology, and psychology (the human side), the technical commission deals with sports science, physics, and technology of equipment and courts. Members of the technical commission are nominated, then appointed. There is a chairman appointed to represent the Technical Commission on the ITF Board of Directors.

We asked Andrew how he became involved in tennis science. Was he interested in tennis and science as a young student? "Not really", he said. "I was interested in music and art and I was quite a good musician even at the age of 10. But during my early schooling I followed a traditional science curriculum: chemistry, math, physics and biology."

We talked about Andrew's interest in art and how that affected his work as a researcher. This is not the first time we've heard scientists and engineers tell us that they were interested in art as young students. The principal investigator of the project, Dr. Jani Macari Pallis, said her parents thought she would become an artist - she was always drawing and building things. She feels an engineer is "part scientist, detective and artist". Tennis scientist and physicist, Professor Howard Brody also told us that he liked to build things as a young boy. Andrew agreed that creativity is very important in science. It provides a wealth of new ideas and aids in finding solutions to difficult problems.

How did he become interested in tennis? "My interest in tennis began about 20 years ago when I worked for Dunlop/Slazenger. With my degree in chemistry, I was part of a team assigned to develop sports equipment. One of the projects was the development of the graphite racquet. As you know, in the late 70's the graphite racquet basically replaced the wood racquet and changed the game of tennis in a revolutionary way. I was fortunate to be involved in that project in the early stages of its development."

"Sports products have some unique characteristics: the materials need to be strong yet light weight and low cost. So my role was to apply material science (the chemistry, physics and engineering of materials) to new sports equipment. At that time this was groundbreaking work. We looked at how advanced materials like composites (a combination of materials - carbon fibers and Kevlar are examples of composites) could be used in sports products."

During our interview with Professor Howard Brody, a member of the ITF Technical Commission, the professor explained to us that the ITF has taken a greater proactive (dealing with issues ahead of time) position under Andrew's direction. We asked Andrew to explain this to us.

"It is the ITF's responsibility to monitor and administer the rules of tennis. New products drive the development of a sport. How do we know if a technology benefits or hurts the game? To preserve the nature of the game we can not wait until a product is in the marketplace. We need to understand and have the knowledge to make that assessment before the equipment hits the market. We actually have to be ahead of the manufacturers to ensure we preserve the nature of the game. I feel that we must understand the technology to understand the issues."

"New technology filters into the sport through equipment and facilities. There must be a balance between technology and maintaining the tradition and basic nature of the sport. Without this knowledge we can not know if we are benefiting or hurting a sport."

We asked Andrew for some examples. "A manufacturer may come up with an idea for a ball coating: How do we know if this benefits or hurts the game? Will it change the nature of the game? The new ball cover might benefit the game with longer ball durability. Let's say that we all agree that there is a benefit - but without understanding the technology how can we know what negative effects it might have."

"Racquets are another area where we want to have a fundamental understanding of how changes affect the game and the players."

"In the area of tennis courts, the materials determine the performance of the surface but the regulations are quite liberal. We are currently standardizing scientific methods to accurately measure the various properties of a court surface. We want to classify surfaces by parameters like shock absorption (energy absorbed by a court from an impacting ball), frictional characteristics (which influence ball rolling versus skidding) and surface permeability (permeable surfaces, like clay, absorb moisture and are typically slower than nonpermeable surfaces)."

We discussed a specific example of this with Andrew: the grass courts of Wimbledon. By the finals, large areas of soil are clearly visible where the grass has been trampled away from fierce tournament play. Court performance also changes as the surface absorbs moisture from rain or dew or loses it from the heat of the sun. "With this process in place we will be able to determine the pace of the court and predict ball velocity and angles. Then appropriate standards for courts and regulations can be defined to ensure consistency among different surfaces. But again we need to have a thorough understanding of how court surface materials affect ball performance."

We asked Andrew to tell us about some of the investigations the ITF has conducted. "There is concern that the speed of the men's professional game is too fast. Game statistics show that the match times are shorter. The fastest men's serves are in the 140-150 MPH range. I believe that we are approaching a limit on human reaction time for the return of the serve. We looked at statistics on the number of tie-breaks and tie breaks at 6-6; they have risen. Players like Rusedski, Ivanisevic, Sampras, Philippoussis use the serve very effectively.

"The tennis court area is a predetermined size, so we looked very carefully at changing the size of the ball. By changing the ball's diameter by 8% this will result in slowing the ball down about .03 sec." That may sound like a very small change, but considering that a professional men's serve only takes about .6 sec to travel from the racquet to the opposite baseline, that's 5% more time. "Although the bigger ball will first be used with the fast courts like grass, it is intended for all courts and recreational players as well as professionals."

Andrew explained that another major consideration is the impact on industry and the players. "The ATP Tour and WTA (men's and women's tours) have representatives within ITF committees and commissions. As well, we are sensitive to the costs and impact rule changes have on the manufacturers. We feel that these decisions need to be reached with support from all parties. Communication with industry is essential."

We told Andrew, that we had seen some very unusual tennis racquets. Professor Howard Brody had even shown us a racquet with fluid in its frame. As the racquet was swung, the fluid redistributed itself. Clearly that's not legal based in the ITF rules. We asked Andrew, "Do manufacturers need the ITF to approve a new ball or racquet. Does the ITF test racquets and balls?"

"Yes, balls are tested by the ITF. Any tennis ball used in a tournament has been tested and approved by the ITF. Like the court surfaces, the balls have their own set of characteristics."

"The ITF does not approve new racquet designs. The ITF administrates the rules and the equipment developers and manufacturers work within those standards. Although the maximum dimensions of the racquet head are specified, racquet rules are actually quite liberal. There are times racquets are sent to the ITF for evaluation to assure that the equipment adheres to the standards - for example the racquet may have a unique stringing arrangement. In general the rules for racquets are quite clear, but grey areas (situations when clarification is needed) do exist."

"There has been discussion regarding limiting the power of the racquet to reduce the speed of the game. The common concern/complaint is that the professional men's game is too fast - it is becoming a game that is increasingly dominated by the serve. Although there are limitations on the maximum size of the head and overall length of the racquet there is no limit on the coefficient of restitution or power of the modern tennis racquet. But before any regulation limits on racquet power can be made, we need better tools to measure how racquet power and frame bending affect ball speed."

"Currently, a machine is being designed that will emulate (reproduce) the serve of a top male tennis player. This will allow us to study the velocity (speed and direction ) and acceleration (change in the velocity) of the racquet during the serve as well as racquet performance." Since the machine can duplicate an identical serve pattern each time, researchers will be able to change the racquet weight, string tension or racquet frame bending to compare overall performance. "We'll be able to quantify (measure) how these variations change the ball's velocity."

We were curious about the new filled balls and asked Andrew about the advantages. "Pressureless balls have been manufactured for a long time. The advantage of a pressureless ball is that it lasts longer. But professional players prefer pressurized balls. Tretorn has developed a new ball which is filled with a low density material which is claimed to make the ball deform more like the pressurized balls do. This ball has been used in several tournaments."

We asked what the biggest developments in tennis science were in Andrew's mind. "Technology has changed and has aided in both the development of new materials and provided manufacturers more effective ways to create products. In the last 20 years carbon fiber materials have become prevalent. The wooden racquets weighted 13-14 ounces and the racquet head had an average area of 68 sq. inches. Now the racquets weight 7.5 ounces, have a much larger head, 110-120 sq. inches and are much stiffer and more powerful. The tools used to investigate problems have advanced. Clearly computers have helped us."

We asked Andrew to tell us about the 1st International Congress on Tennis Science & Technology. Sponsored by the ITF, the 4-day conference will be held in Roehampton, England during the first week in August, 2000. "We felt that this was the time to bring everyone together: academia, the manufacturers, researchers, ITF members and other interested parties. Tennis research is conducted all around the world. The conference gives us the opportunity to pool and showcase the current state of knowledge, to collaborate and exchange ideas. The conference sessions are split into 3 groups: equipment , facilities & tennis presentation and player sport science."

What changes do you see for the game in the next 5 years? "The essence and nature of the game will of course remain the same, but slight changes will be made as new rules are adopted and technological advances enhance the game. New product development will provide greater choice for consumers. We want to see this make the game more enjoyable and fun. Of course our hope is that the sport will grow from the current 60 million regular players to 70-80 million."

The Tennis Sport Science team would like to thank Andrew Coe for his time and this interview. I was able to discuss with Andrew some of the concerns and challenges that we have had to face on our project as well and I appreciated his openness and comments.