Mysteries of the Heavy Ball: Introduction
"The Heavy Ball." It's a mythical term. "His ball was so heavy it was like hitting a bowling ball." Most tennis players and coaches have had the experience of playing an opponent whose ball seemed unusually "heavy".
Maybe the ball seemed to get on top of you before you could respond. Maybe the ball felt like it was going to rip the racket out of your hand. Maybe it felt like the ball would by pass your strike zone altogether and bounce over your shoulder or even your head.
Everywhere I go in tennis I hear different versions of the same story. This player or that player had the "secret" of the heavy ball. It was Don Budge, Bjorn Borg, Tomas Muster, or Pete Sampras--or some legendary local college or pro player that you or I never heard of. "This guy hit the heaviest forehand I've ever played against."
So "heavy ball" is a term with a lot of connotations for a lot of people. But does it have any real meaning? Is there in fact any such a thing as a shot that is really "heavier"? If so can we understand it, quantify it, and/or teach it?
If the heavy ball does really exist, it must be some combination of speed, spin, and shot trajectory. But what combination? Is it something that's just natural for a few gifted or lucky players? Is there a way to intentionally maximize the weight of your shots?
In this section of Tennisplayer, we've set out to investigate these questions in a different way. Thanks to new filming and analytic technologies, it is now possible to measure the shot signatures of the top players and to distinguish how they play by the quality of the ball they produce.
Over the last several years, researchers from Advanced Tennis Research(AdvancedTennis.com) have been investigating these factors of ball speed, spin, and trajectory, and beginning to put the pieces of the puzzle together. A big part of the story is the evolution in technologies that makes this possible. And that's part of the ongoing story we plan to tell
Ball Speed
We'll start with ball speed, and the groundbreaking research Advanced Tennis scientists began on the speed of the ball in 1997 and 1998. This was the first quantitative study to measure the speed of the ball in pro tennis, beyond what the radar guns told us about the initial velocity of the serve. We not only studied the speed of the serve, but also of the groundstrokes, the returns and the volleys.
Although it's absolutely invisible to the human eye, virtually every shot in pro tennis lost half or more of its speed by the time it reached the opponent's baseline.
In the first article we go into detail about how we developed this information, what the results were, and what it might mean for players looking for an edge.
Ball Spin
After looking at the study of ball speed, we'll go on to look at the first ever study of the actual spin rates in pro tennis. In 1997, we filmed at the U.S. Open using a new high speed digital camera technology that filmed at 250 frames per second. This was the first time that live professional matches were ever studied by a camera that was fast enough to actually "see" how the ball spins.
How fast was a Pete Sampras serve really spinning? How about an Andre Agassi forehand? Our camera allowed us to answer these questions. During the course of 5 days, we built up and extensive data base of several hundred spin events with top professional players.
We found for example that there was no such thing as a "flat" first serve in the pro game. In reality, a 120mph Pete Sampras serve was actually spinning at an average of over 2500rpm.
We also found that although many people believed that Andre Agassi's forehand was hit with "heavy" topspin, it was actually spinning at about 1800rpm, less than half what some of the European players were developing.
We also saw for the first time what happened to spin during the bounce on the court. Surprisingly, we found the friction between the ball and the court created as much topspin as the initial hit (and sometimes more), something which had important implications for the creation of the "heavy ball."
These studies of speed and spin opened a window on the literally invisible world of ball dynamics. They also raised almost as many questions as they answered.
We were able to put real numbers to spin and speed in pro tennis for the first time--key components in trying to understand the heavy ball. But how did speed and spin actually interact?
The next step in the research was to measure speed and spin simultaneously, instead of in separate studies. To do this required a new, more elaborate filming protocol and new original motion analysis software, developed by Nasif Iskander.
Nasif was able to measure the speed of 10 returns hit by Pete's opponents, as well as 3 returns hit by Sampras.
In 2000 we were able to put these new tools into action. We were able to film and compare the ball dynamics of two of the best servers in the history of the game in live tournament play: Pete Sampras and Greg Rusedski. For the first time we were able to measure the speed and spin of the serve over the entire course of the flight. Greg Ryan performed the critical and painstaking task of putting the together to form our most complete picture yet of the heavy ball.
A critical advance in Nasif's software was the ability to measure the components in the spin of top players, for example, the level of sidespin and topspin in the deliveries of Sampras and Rusedski. In addition, Nasif developed a "shot simulator" that actually allowed us to measure how changing amounts of spin influenced the curve and the drop of high speed professional serves.
The results were again surprising. We found that there was in fact no such thing as a "topspin" serve, that the majority of spin in the deliveries of both players was sidespin not topspin. But a critical difference turned out to be the relative amounts of topspin.
These differences in the type and amount of spin had a significant impact on the quality of the ball they produced. And it had a significant effect on the total "heaviness" of the shot at the time of the return.
Since Advanced Tennis completed its initial studies of ball speed and spin, the technology has continued to evolve, making even more detailed and precise studies possible that can contribute to our understanding of the nature of the heavy ball in new ways.
Currently Advanced Tennis is engaged in a collaboration with Hawk-Eye technologies in London, the developer of the "Shot Spot," which has taken a prominent place in ESPN tennis broadcasts, reviewing line calls. "Shot Spot" is based on amazing technology developed by the brilliant young English scientist Paul Hawkins, who first applied it in cricket.
To the average television viewer, this is exciting because it allows for the potential "instant replay" review of the controversial calls which frequently have an impact on the outcome of matches (not to mention the fragile emotional psyches of the players).
But in reality the "Shot Spot" technology can tell us far more, because it is actually measuring the entire trajectory of every shot hit in professional tennis. This means Shot Spot can tell us the exact speeds of the shots of the top balls at any point in the flight of the ball, as well as the path each shot takes.
The one factor that Shot Spot cannot directly measure is spin, which requires an additional, even faster high speed camera trained exclusively on the flight of the ball.
In 2004 Paul Hawkins agreed to collaborate with Advanced Tennis in taking the heavy ball analysis to the next level. This meant that Shot Spot would allow us to combine their speed and trajectory data with our high speed spin data. Together we were able to film matches of Roger Federer, Andy Roddick, Marat Safin, and Lleyton Hewitt. This will allow us, for starters, to compare the spin Roddick generates on his serve to Sampras, or Federer.
Over time we hope the end result will be a comprehensive and even more accurate picture of what actually happens when pro players hit the tennis ball. Our goal is that by combining speed, trajectory and spin, we will be able to further unravel the shots of pro players and facilitate the quest for the heavy ball. So Stay Tuned.
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Advanced Tennis wishes to acknowledge that the initial data on ball speed and ball spin was developed as a collaboration with Cislunar Aerospace, funded in part by a grant from the Learning Technologies Project at NASA. Their contributions are gratefully acknowledged.
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