Tennis courts have supposedly been getting slower for decades. It’s one of those things everyone seems to agree on. It goes something like this: grass is no longer particularly fast, hard courts increasingly resemble clay, and the days when players needed fundamentally different games to succeed on different surfaces are long gone.
And there is certainly evidence that modern tennis looks considerably more similar across surfaces than it once did. Just look at any rally-length graph across the decades. During the late 1970s and early 1980s, clay-court rallies averaged more than eight shots at their peak. Hard-court points generally lasted around four shots, while grass produced even shorter exchanges.
By the late 2010s, the differences had narrowed dramatically. Clay averaged roughly five shots, hard courts around 4.5, and grass fewer than four. Surely that proves the homogenization theory? Right?
Well, not quite.
Because the graph measures how long rallies last, rather than how quickly the ball travels through the court. And those are two very different things.
Tennis Courts Have Converged, But Have They Actually Slowed Down?
Rally-length graphs have something interesting that often gets overlooked. The biggest historical change isn’t grass producing longer rallies; it’s clay producing much shorter ones. From its extraordinary peak around 1980, the clay-court average falls sharply before stabilizing around five shots during the 1990s. Meanwhile, grass and hard courts experience considerably smaller changes over the same period.
If the explanation were simply that tournament organizers had slowed down faster courts, why would clay have experienced the most dramatic decline in rally length? It’s the first proof that something is going on. Tennis analyst Jeff Sackmann explored this question in considerable detail in a 2023 study for Tennis Abstract.
Using the Match Charting Project and controlling for the playing styles of the competitors, he found that before 1995, clay-court rallies were expected to last roughly one shot longer than hard-court rallies involving comparable players. Since 2016, that difference had fallen to just 0.16 shots.
That is really compelling evidence of a convergence in rally length. But Sackmann’s more recent 2025 investigation produced a rather surprising counterargument. Using ace rates to estimate playing conditions, he found that the difference between fast and slow tournaments had barely changed over more than three decades.
Wimbledon’s relative ace-based speed rating was 1.13 in 1991-92 and 1.14 in 2024-25. Monte-Carlo, meanwhile, went from 0.58 to 0.57. Basically identical. Ace rates are, of course, not a perfect measure of surface speed either, particularly when serving ability and equipment have changed so much.
Nevertheless, these findings challenge the idea that courts themselves have become dramatically more similar. Even Wimbledon’s famous switch to 100% perennial ryegrass in 2001 is frequently misunderstood.
According to Wimbledon itself, the change was introduced to improve durability, with research suggesting it would not alter the perceived speed of the courts. Obviously, that doesn’t mean playing conditions have remained completely unchanged. Surface preparation, balls, temperature and even humidity can influence how quickly a court plays.
But attributing the convergence of rally lengths entirely to slower courts is an enormous oversimplification.
Perhaps the Players Have Become Homogenized Instead
Another explanation might be considerably more accurate. The way tennis is played has changed. During the 1980s and 1990s, players routinely made substantial tactical adjustments depending on the surface. Pete Sampras built much of his success around attacking behind his serve and approaching the net. Ivan Lendl could engage in lengthy baseline exchanges on clay while playing more aggressively on faster courts.
Today, however, the basic idea of professional tennis is remarkably consistent. Carlos Alcaraz, Jannik Sinner and Novak Djokovic might adjust their court positioning or shot selection depending on the conditions. Still, they generally rely on aggressive baseline tennis across all three surfaces.
And one of the biggest reasons for that transformation is equipment. The introduction and widespread adoption of polyester strings fundamentally changed what players could accomplish from the baseline.
Gustavo Kuerten’s 1997 Roland Garros triumph with Luxilon strings was an early demonstration of what was possible. Players could swing aggressively while generating enough topspin to keep the ball in play. More importantly, they could hit dipping passing shots that made approaching the net considerably more dangerous.
As Tennis.com explained in its retrospective on polyester strings, the technology helped make attacking shots from defensive positions increasingly effective. Suddenly, serving and volleying wasn’t necessarily the most efficient way of playing on grass. Staying at the baseline became viable almost everywhere.
Improved movement, athletic conditioning, and defensive ability reinforced the trend. Players could cover more court, recover from difficult positions and keep points alive without sacrificing as much attacking potential. The result was a gradual convergence in playing styles, even if the courts themselves didn’t change.
Consider this as well. Rally-length graphs don’t identify the underlying match sample or explain exactly how rally averages were calculated. Historical tennis footage and detailed point-by-point records are much less comprehensive than modern data. That makes the unusually high clay-court averages around 1980 worth treating cautiously.
A 2024 study published in the Journal of Sports Analytics, examining more than 500,000 men’s points from the Match Charting Project, found average rally lengths of 4.3 shots on clay, 3.8 on hard courts and 3.2 on grass.
So the differences remain real, but the authors also found that player characteristics, particularly height, helped explain rally-length distributions. In other words, who is playing matters enormously, alongside where they are playing.
The Last Word
Tennis has unquestionably become more homogeneous in the way it is played. What remains much less certain is whether the courts themselves are primarily responsible. The disappearance of traditional serve-and-volley tennis, the influence of polyester strings and the emergence of increasingly athletic baseline players offer explanations that cannot simply be dismissed.
And the historical data contain an important contradiction: rally lengths have converged even where ace-based measures suggest that differences between surfaces have remained remarkably stable.
Perhaps tennis didn’t need every court to slow down for the sport to start looking the same everywhere. Perhaps the players simply discovered a style of tennis that worked almost everywhere.
Main Photo Credit: Danielle Parhizkaran – USA TODAY Sports