What Tennis Can Teach Us About Technology

In the winter of 1947, Howard Head, an aerospace engineer, was skiing down Stowe Mountain when he decided that wooden skis were a terrible idea. He kept tripping on the long hickory blades; the material was too heavy for such a nimble sport. On the train back to Baltimore, Head began sketching out a new ski made out of airplane parts, focusing on the aluminum alloys and plastic laminates used to construct the fuselage. It took a few more years of stubborn tinkering—Head’s first 45 prototypes came apart on the slopes—but by the 1960s his aerospace skis were dominating at the Olympics. 

In 1972, Head sold his skiing company and settled into retirement. To stay in shape, Head started taking tennis lessons. However, he soon realized that he wasn’t very good at the game; his shots careened all over the court. Head could have practiced more, but that didn’t seem very fun, so he decided to fix the tennis racket instead. At the time, virtually all rackets were made of wood, with an elliptical surface area of roughly 70 inches. While companies had experimented with slightly larger rackets—more surface area meant a bigger sweet spot—they were ultimately constrained by the weight of wood. 

Head’s insight, which he laid out in a 1974 patent application, was that new materials could eliminate these tradeoffs. Head settled on a composite blend of carbon fiber and resin, which allowed him to create a racket with 40 percent more surface area and a far larger sweet spot. The end result was a piece of equipment that made the game much easier for amateurs. 


In 1978, Head got one of his new oversized rackets into the hands of a talented 16-year old named Pam Shriver. Although Shriver entered the U.S. Open unseeded, she ended up beating Martina Navratilova in the semifinals. Pros took notice: by 1984, composite rackets had taken over the tour. (John McEnroe was the last player to win a major tournament with a wooden racket, beating Bjorn Borg at the 1981 U.S. Open.) You can see the triumph of composites in this chart:


This is a portrait of technological disruption. As such, the game of tennis in the post-composite age provides an ideal case-study with which to investigate the impact of innovation. That, at least, is the premise of a new working paper by the economists Ian Fillmore and Jonathan Hall. By looking at every men’s professional tennis match played between 1968 and 2014, Fillmore and Hall were able to map out the unlikely impact of Howard Head’s invention. 

The first thing they found is that composite rackets dramatically shifted the demographics of the pro tour. In the mid-1970s, when wooden rackets still dominated, nearly 20 percent of all matches featured a player above the age of 30. By 1990, that number had shrunk to roughly 5 percent of matches.

The youngest players made up the difference. Between 1975 and 1984, the percentage of matches involving players under the age of 21 nearly tripled, to 30 percent. 

Why were composite rackets so hard on the oldest players? Head, after all, invented the composite racket to help old guys like himself hit good shots; it was supposed to level the playing field. And yet, his invention ended up doing the exact opposite, tilting the competitive balance in favor of youth. 

To understand how this happened, it’s important to look at how composite rackets were actually used on the pro tour.  While Howard Head was trying to create a bigger sweet spot for amateurs, professionals didn’t really need a bigger sweet spot. Instead, they used these new rackets to give their shots more topspin. As noted by the physicist Rod Cross, the best players using wooden rackets were only able to impart a topspin of about 200 rpm on a typical forehand. However, the increased width of the composite racket meant that players could attack the ball at a more extreme angle, and thus generate 1000 rpm of topspin. That’s a five-fold increase in ball rotation, which allowed them to hit with more velocity, and to create higher bounces that are harder to return. (Just imagine the consequences for baseball if pitchers invented a breaking ball with five times more spin. The home run would soon become a relic.)

What does topspin have to do with older players? To take full advantage of Head’s innovation, experienced players had to quickly learn a new set of tactics and techniques. They had to change their grips, stances, and swings to maximize spin. Interestingly, the increased experience of veterans seemed to interfere with this adjustment, which is why their exit rate from the tour doubled between 1970 and 1984. Head invented the composite racket to make it easier for older players like himself to hit good shots. He ended up ridding the pro tour of nearly everyone over 30, at least for a generation of players.

There’s a larger lesson here: when it comes to technological disruption, we inevitably fail to anticipate the real-world consequences. The public sphere is lousy with pundits and prophets, boldly forecasting the future impact of the latest technology. Winners, losers, etc. But what history teaches us is that nobody knows anything.

In their paper on tennis, Fillmore and Hall briefly reference the impact of photography on modern painting as another example of how technology disrupts in unpredictable ways. After J.M.W. Turner saw a daguerreotype for the first time, he declared: “This is the end of art. I am glad I have had my day.” Turner saw the photograph as a dire competitive threat, since it meant everyone could engage in the business of representation; verisimilitude had become a cheap technology. But Turner was wrong—the photograph didn’t kill art, it just forced painters to seek out new cultural markets. Instead of aiming for realism, they began experimenting with abstraction, focusing less on the depiction of objective reality and more on its subjective qualities. The camera opened up space for Cezanne.

Or consider basketball, a game that has been transformed by the “innovation” of the 3-point shot. Although it might seem obvious that three-pointers would increase the value of guards—they’re the ones most likely to take the shot—Gannaway et al. showed that the players who have gained the most value in the NBA labor market are tall centers who play close to the basket. 

What explains this counterintuitive result? Defensive strategy. When players move out to contest three-pointers, they leave more space for the interior game. Furthermore, the long ball can be taught, as evidenced by the NBA’s steadily rising three-point field goal percentage. (In 1983, teams made 23.8 percent of their three-pointers; in the 2017-2018 season, they made 36.2 percent.) What can’t be taught is height.

Or look at the effects of the great disruption of our time: computers. Last year, I wrote about the effects of digital technology on human capital. Interestingly, the widespread adoption of software seems to be increasing the value of social skills. At first glance, this makes little sense. Shouldn’t the computer age reward those minds best at computation? However, the researchers found that many cognitive skills are easily replaced by cheap machines. As a result, employers increasingly seek out humans who are adept at the very things software can’t do, such as manage other people and settle interpersonal issues.

We live in a time of relentless technological change. These case studies help explain why such change is so unsettling. Our inventions aren’t just altering the competitive landscape—they are doing so in completely unpredictable ways. Those older tennis players probably thought the oversize racket would help them compete with younger players, compensating for their slight decline in athleticism and speed. They were wrong.

And the cascade of unexpected consequences never stops; when it comes to the impact of technology, change is the only constant. The rise of abstract expressionism created a resurgent demand for realist portraiture; in the current NBA game, the most valuable players aren’t just big men—they’re big men who can also hit three pointers. (There’s a reason Boogie Cousins averaged more than six three-point shots per game last year.)  

Tennis is no exception. For nearly twenty-five years, the percentage of matches involving older players  remained below the levels of the wooden racket age; composites had turned the sport into a young person’s game. But then, starting around 2000, the share of matches involving players older than 30 began to steadily increase. By 2014, these veterans played in a higher percentage of matches than ever before.

What's more, these older players are dominating the sport. As I write this, the top ranked player is 31-year-old Rafael Nadal. He’s closely followed by 36-year old Roger Federer, the greatest player of all time and recent Australian Open champion.* 

Both men use the latest composite rackets. Their shots are loaded with topspin. 

Fillmore, Ian, and Jonathan D. Hall. "Technological Change and Obsolete Skills: Evidence from Men’s Professional Tennis." (2018).

*Serena Williams continues to dominate the women’s tour at the age of 36.


The Trick Shot: Using the Whole Court

Federer makes full use of the court — including the service-box areas — better than anyone else on the tour.

Most players (like Lleyton Hewitt) spend their time hoping to keep the ball deep. Federer seems to spend his time thinking about how to use the full space.

He has one forehand shot that I’ve never seen another player use. He takes it off a short, low ball (1) when he’s up around the center service line and moving forward and toward the backhand side. He’ll really wrap his wrist around this shot, getting such exaggerated topspin that the ball leaps over the net and immediately lands inside the opposite side (deuce court) service box (2).

His opponent, back at the base line, is taken by surprise and forced to rush up as if he were chasing down a drop shot.

Often, Federer’s shot is a clear winner. If not, he is at the net, ready to take the rising return — it’s almost always going cross-court (3) — with a volley (4) to end the point.

Source: NYTimes

Breakdown of Roger Federer’s tennis serve

Roger Federer has one of the most smooth and effortless tennis serves in the world and he has one of the most underrated serves going around. Although Federer does not reach quite the speeds of some of the other professional tennis players, he is much better in many of the other aspects of the serve. Federer’s serve is a great model for young people to try and emulate as it is a simpler, more classical and has less extreme elements than other professional tennis athletes. Below is a rundown of the tennis legend’s serving technique in accordance to the biomechanical teaching cues above.

1.Federer never rushes his technique; he starts with his hands together with his racquet drawn back and down whilst his left hand drops.

2.Federer tends to let his racquet trial down instead of tossing and lifting the racquet at the same speed. He shifts his energy in to his quadriceps and bends his legs throughout this motion.

3.His wrist is loose and his arm is bent as the ball goes up. His ball toss is slightly in front of him and fairly high in the air. He turns his shoulder in such a way that the opponent will have trouble trying to predict what type of a serve he is going to produce.

4.This is Federer’s famous trophy position as it is now known as. He is basically underneath the ball with his chest pointing towards the sky looking at it. His racquet is about to drop down and is in mid loop. At this moment he is able to spring upward on towards the ball, putting all of his available energy at the ball.

5.This is the point where his racquet is at the lowest point. However, at this moment his torso, legs and chest are all on the way up. His racquet at this stage still hasn’t moved up. The purpose of his movement at this stage of the skill is to make the conditions perfect for the racquet to be able to spring up as fast as possible.

6.At this stage his arm is completely extended. There is a small arch to his body, but this is due to him moving up and out. As his racquet is so high it gives him the chance to hit the ball into his opposition’s service box from an improved angle. His head and eyes stay up and focused at the point of contact even after the serve has been played.

7.His head is still up even though the swing is just about in completion. His wrist has rotated onto the ball whilst his momentum has moved onto the court. His left arm is kept close to his body in order to maintain balance. Although this part of the serve is meant to be the most violent looking part of the swing, Roger makes it look effortless and smooth.

8.The landing of Roger is just on the inside of the baseline. His right foot moves back which helps him balance. His knees are also bent apart at this stage to help aid the landing. He is not looking towards the court and is positioned in a way in which he could easily move to the left and right of the court to return the next shot which comes his way.

First Serve: Taking Charge Early

Federer has a terrific serve, regularly clocking in at 115-125 m.p.h., but unlike, say, Andy Roddick, he’s not looking for the ace.

Instead, he uses it to set up a killing follow-up shot or to take command of a rally. His most basic service play is designed to set himself up for a forehand winner.

As Federer serves, his momentum will carry him a couple of steps into the court, where he’ll be looking to hit a forehand.

If he’s hitting a first serve from the deuce (right) court to a right-hander, like Roddick, look for him to go for a flat, hard one (1) intended to prevent the righty from taking his requisite full swing. Roddick can bet the house and try a forehand screamer to Federer’s backhand corner.

Mostly, though, he’ll go cross-court (2) in order to buy time to get back into the court and protect his exposed backhand.

This is a race against time, and if his return is not sufficiently hard and deep, Federer will win the race — stepping in to hit the down-the-line forehand winner (3).

Writen by: Patrick McEnroe and Peter Bodo Source:NY-Times

Service Return: Attacking the Second Serve

Federer is very difficult to ace, yet he’s not heralded for his return, mostly because he doesn’t try to do too much with it.

He just wants to get it back, deep, to wipe out the natural advantage of the server.

Federer will attack the second serve, especially if an opponent is trying to coax an error out of his backhand.

Federer will often step around the backhand to hit a big forehand return, an especially valuable move when playing a left-hander, like Rafael Nadal, whose kick serve (1) bounces high and away from Federer’s backhand in the ad (left) court.

Federer rarely tried stepping around at the French Open; instead, he spent the afternoon hitting his least favorite shot, the high backhand, which frustrated him.

At Wimbledon, however, he began to step around the backhand. It paid off, partly because the kicker draws the returner far enough out of the court to give Federer two lethal options: the bullet down the line (2) or the inside-out forehand (2a) at a severe angle back to Nadal’s forehand side.

Writen by: Patrick McEnroe and Peter Bodo Source:NY-Times

Cross-Court Rally: Forcing an Error

Federer is masterly at executing the low backhand slice (1) to his opponent’s forehand or backhand, inviting a cross-court return to Federer’s forehand.

Opponents like James Blake sometimes try to beat him to the punch.

If Blake chooses to go with a slice to Federer’s forehand (2), the backswing will give him away. Federer can use his flexible wrist and superb timing to rip a shot cross-court with heavy topspin (3), and he can either follow his momentum to the net or stay back if his shot isn’t quite penetrating enough, content that he is now in control of the point.

If he stays back, the stage is set for a forehand-to-forehand cross-court rally (4, 5) that is very hard to win against Federer.

It’s dispiriting to have to fight off those high-jumping, topspin forehands. Hitting one at shoulder height is like being pushed by a 100-pound weight. The shots are like blows to the body; after three or four, most players will make an error (6).

Writen by: Patrick McEnroe and Peter Bodo Source:NY-Times