by Wendy Ogbourne
During the last two weeks of January, I am sure that many of you will have been watching and enjoying the Australian Open tennis tournament, as I did.
In the 60’s I played “hit and giggle’ tennis, mainly as an excuse for a social gathering with other young mothers. I was never a good player, but I had fun.
The game of tennis has always been all about physics – velocity, acceleration, trajectory, and above all, angles. Experts handle all these things instinctively, and they now have computer analysis and statistics, sports coaches, trainers, psychologists, fitness experts, and a host of other related specialists who all contribute to the overall package that is needed to become a top player. But what’s fascinating me at the moment is the application of science to the equipment itself, and the changes that have occurred which have produced the game of today.
Let’s look at tennis racquets. Top players pay over $300 for a racquet, with $50 for each restring. The purpose of a tennis racquet is to change and control the speed and direction of a tennis ball. This happens in approximately 5 thousandths of a second, so there is a huge force exerted both on the racquet itself, and on the wrist and arm of the player. Forty years ago, racquet frames were all made of wood. They were quite heavy, and though giving the players speed and control, they had their limitations. In the late 70’s, metal frames, largely a mixture of graphite with titanium, were introduced for the first time. These new frames were much lighter and stronger, allowing the players to swing faster and hit harder. First serves are now routinely over 200km per hour and forehand passing shots a similar speed.
Because racquets were now lighter, it also became possible to increase the size of the racquet head, especially the width, which allowed more surface area for hitting. We’ve all heard of the “sweet spot” on a racquet. That’s the spot, approximately in the centre of the racquet, that allows the maximum control of the ball, with the minimum stress on the player’s arm. Clearly if the size of the “sweet spot” can be increased, players have more options open to them when making their shots. Swinging the racquet head faster produces more spin on the ball, which leads to longer base-line rallies, more court-coverage, requiring the players to run faster and react quicker. They therefore need a much greater level of overall fitness to compete. Compare the more sedate serve-and-volley games of old.
To cope with the increased speed and power generated by the modern racquets, the size of tennis balls will soon be increased by 6%. The current ball sizes, though fine with the old wooden racquets, are just too fast for today’s game. Making them slightly larger will slow them down slightly in the air, and allow the players 10% more time to receive serves. With tennis now a million-dollar industry world-wide, it’s important to ensure that matches remain exciting and somewhat unpredictable for spectators. It would be fairly boring if all service games were won to a “love” score, with a succession of aces, or balls that were impossible to return.
Technology has also made its mark, with the introduction of the Hawk-Eye electronic line-calling system. This uses 6 or more computer-linked television cameras situated around the court. They track the path of the ball, and the images are received by the computer and combined together to produce an accurate 3D representation of the path of the ball. This vision can then be played back instantaneously, to determine the accuracy of the umpire’s ruling on disputed close line-calls. This system has proved popular with players, reducing controversy, and also with spectators, adding to their involvement.
Technology is adding to the interest for at-home tennis spectators in other ways as well. The match commentators have a seemingly endless array of statistics and match analysis information on screens at their fingertips. They can read off the speed of serves, tell us about numbers of aces, proportion of winning to losing shots, averages from past matches, who wins most 5-setters, even show us a picture of where the serves have landed on the court. Whatever you want to ask, they have the answer.
It’s a trend that’s sure to continue. Tennis, like other sports, such as cricket with the now established limited-over matches, has moved decisively into the 21st century. Technology is here to stay.
© Wendy Ogbourne, 2010
This entry was posted by wendy on Monday, March 1st, 2010 at 12:00 am and is filed under Science Stuff.
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