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Advanced Tennis: Sampras Serve
Deception

by John Yandell 

In addition to his consistency, his accuracy, and the extremely heavy quality of his ball, Pete Sampras has another major advantage over other top pro servers: his deception. This is his ability to disguise completely the direction, speed, and spin of his delivery.  

The nature and the location of a particular Sampras serve is virtually impossible to anticipate.  This is because he hits all his first serves off exactly the same toss with exactly the same ball position at contact.

Pete can serve wide, down the T, or to the body in both service boxes with a wide variety of speed and spins, but these different serves are impossible to read until the ball is already on its way to the returner. 

On a 120mph serve, it takes the ball only about 2/3’s of a second to travel from the server’s racket to the returner’s racket. In that very brief interval, the returner must recognize the location of the serve, move into position, and execute a return. 

Anticipating the location by reading the server’s toss or subtle keys in the motion can be a huge factor in returning well in pro tennis. Against Pete, other top pros have to deal with his deadly combination of spin and speed with no advance warning. This ability to produce any placement off the same toss is yet another key element in Pete’s technical superiority, and his phenomenal serving effectiveness. 

According to his tour coach Paul Annacone, Sampras developed this ability to disguise his serve as a young player. His coach at that time, Pete Fischer, would wait till the toss was in the air then call out the location, “wide” or “middle.” 

Since Pete himself didn’t know where he was serving until he was well into the motion, there was nothing in his stance, toss, or wind up that could give the location away.

How difficult is it to read the direction? In filming Pete for ProStrokes Gallery, we found the difference in his service motion when he is going wide or going down the middle is virtually invisible to see with the naked eye on traditional video, which records 30 frames per second. 

To see this difference on a consistent basis requires the use of special high speed digital cameras, such as those used by Advanced Tennis researchers to film Pete and other top players.  These cameras film with a much higher frame rate -- 250 frames per second versus the standard 30 frames per second. This is more than 8 times the speed and 8 times the information recorded in ProStrokes digital video, or used by broadcast television. 

This high speed frame rate allowed us to see the differences in Pete’s placements, and also, how small these differences really are. Everything in his motion - his stance, his wind up, the path of his racket - seems identical until about two hundredths of a second before contact.  Think about that! Two hundredths of a second!  

At that point - about two hundredths of a second before contact - we can see the angle of the racket head changes slightly as it moves to the ball. This slight variation in the angle and path of his racket head determines both the location of the ball and the type and amount of spin. 

With high speed video, we can see when Pete is serving the T, the racket head flattens out slightly more before the hit, so the face is almost parallel to the baseline. When Pete serves wide, the racket head approaches and strikes the ball slightly more from the side. 

For the wide serve in the ad court, the racket moves to the ball more from the left, striking the left side of the ball and then continuing on this left to right diagonal. In the deuce court, the racket face is more open in relation to the baseline, with the right edge of the frame leading the motion more. The contact is more on the right side of the ball, with the racket continuing further to the right after the hit compared to the serve down the T.

The balls down the T are traveling with heavy spin, spinning around an axis of about 1 o’clock or one thirty. The wide ball in the ad court may spin at a slightly steeper angle. The wide serve in the deuce court spins on an axis closer to 2 o’clock and has more sideways rotation or slice.

The angle of the racket head after the hit reflects these differences. The amount of pronation is a function of the angle at which Pete contacts the ball. On the wide serve in the ad court the racket head pronotes slightly more than on the serves down the T. On the wide serves in the deuce court, it pronates slightly less. 

The changes among the different serves are so subtle that, going back to the 30 frame/second video to find still images for this article, we had to review over 200 first serves to find the few critical frames that show how his racket actually changes path to change direction and spin. 

It’s possible that Advanced Tennis 3D dimensional analysis may eventually be able to quantify additional, earlier differences in the racket path as the racket moves from the drop to the contact, but again, these changes, if they exist, happen faster than the human eye can actually record. Also of interest is the actual angle that the racket is moving on at the moment of contact, as well as the precise spot the racket contacts on the face of the ball for the different serves.  These are questions that can only be answered through further high speed digital filming and analysis. 

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To view the complete ProStrokes Gallery of digitally mastered Pete Sampras serves, click here.

For more information on John Yandell's Advanced Tennis Research Project, click here.

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