Sampras Serve:
The Mystery of the High Elbow

Is there an explanation for Pete Sampras's high elbow bend? Yes.

Last month we posted over a hundred high speed videos of the serve of the great Pete Sampras—maybe the greatest serve of all time. (Click Here.) Over the years on Tennisplayer we've published more articles on his motion than any other stroke in tennis history, with the possible exception of Roger Federer's forehand.

There was my initial 8 part series on Pete's serve, beginning with our inaugural issue 13 years ago. (Click Here.) Then the 3 part series I did with Brian Gordon based on the only quantitative analysis ever of this incredible motion. (Click Here.)

There is also the groundbreaking article I did on the amazing combination of speed and spin in Pete's serve, compared specifically to the speed/spin combinations of another great server, Greg Rusedski. Not to mention in the original Stroke Archive, a detailed portrait of over a hundred more stroke files. (Click Here.)

Ducking the High Elbow

The elbow bend: a cause or an effect?

But one thing I never addressed—ducked actually—was one of the most distinctive characteristics. His high elbow bend so soon after contact. Higher and sooner than any other player we have ever filmed.

To me it was a puzzle. Other analysts claimed it was a key—or even the key to his motion. But since it happened after contact—well after contact--what causative role could it play? If it was an effect, though, what was it an effect of?

On Tennisplayer our understanding of the game has been progressive. Delving more and more into the high speed footage to uncover aspects that are invisible to the naked eye.

That has been nowhere more true than on the serve. Our more recent studies have explained more about the upward swing in general. And now I can see how that applies to Pete and in particular that distinctive high elbow bend.

Two Factors

Looking again at this high speed footage after many years, I think I understand the mystery now. There are two factors.

The internal shoulder rotation drives the hand, arm and racket as a unit.

Research has shown that the rotation of the hand, arm and racket in the upward and outward swing is one of the major contributors to racket head speed. The best servers turn the racket over on edge after contact. For the clearest explanation of that ever, look at the article by Chas Stumpfel in the Biomechanics section. (Click Here.)

The common term for that rotation is "pronation," which is good enough to identify what we are talking about, but is actually technically incorrect. This rotation is actually driven by the rotation of the upper arm in the shoulder joint.

The forearm, hand, and racket come along for the ride. They rotate as a unit. Technically it's called internal shoulder rotation.

Pronation, technically, is the independent rotation of the forearm at the elbow. That really isn't a factor, since everything, including the forearm, rotates together from the shoulder.

This unitary rotation--and specifically the timing of it—is one of the factors that explain why Pete bends the elbow earlier and more than anyone else we've filmed. How is that?

If we look at when Sampras completes this rotation, it is sooner and higher in the motion than the vast majority of top players. Typically, he has turned the racket completely over with his hand still well above head level.

Most pro servers reach full rotation later and lower than Pete.

From contact to the full rotation takes less than a tenth of a second. Few other pro servers—with the possible exception of John Isner and Milos Raonic—complete that rotation at the same point.

For comparsion, Andy Roddick reaches the same point of full rotation with the hand at about shoulder level or a little above. Roger Federer is about the same.

Speed with Spin

What does that mean? Our speed/spin study of Pete's serve shows that he was able to generate 125mph on his first serve with around 2500rpms of spin. That's more, up to twice more, as some servers serving at the same speed.

That's what made his serve so incredibly heavy. Furthermore his serve not only had heavy spin, it had a higher topspin component that caused his ball to bounce several inches higher than other players.

Higher than a great server like Rusedski who matched Pete's overall spin, but had less topspin and more slice in his delivery. As Scoop Malinowski's article on Facing Sampras shows (Click Here) that serve weight—combined with his incredible accuracy-- made players feel that his serve was almost impossible to return.

Watch the natural relaxation and bend of the elbow just after full rotation.

So how does that relate to the high elbow bend? We see that in all players, the elbow bends at some point in the followthrough. This is the consequence of deceleration and relaxation after the hit. As the followthrough progresses, gravity and the weight of the racket cause the elbow to bend as the hand falls.

The bend begins after the completion of the hand, arm, and racket rotation. It's natural and automatic. It isn't a conscious, mechanical movement.

And certainly that is true for Pete. It's just that it starts earlier than most players. And the bend appears much more pronounced because the arm is so high.

Factor Two

But there is a second factor to consider in why this bend is so distinctibe in his followthrough. That relates to the spin levels in his delivery.

Rotating his arm in his shoulder joint early indicates phenomenal racket head speed. But beyond that Pete is hitting more radically upward and outward across the ball, which probably explains the high level of topspin.

Look at the difference in how far to the right the hand moves for Pete, compared to John Isner.

We can tell this by looking at the position of his arm at the completion of the rotation. It's visibly further to his right compared to other servers. Look at the spacing in relationship to his torso. When the racket face has turned all the way over, his hand is probably a foot to the right.

Compare that to Isner. He has even more internal shoulder rotation than Pete. But look where his hand is at the completion of the rotation, closer to the edge of his body.

From full rotation, Isner continues more straight ahead into the followthrough, and his elbow bend is later, similar to most other pro servers.

So Pete swings more to his right, and from there, his elbow bend starts sooner as his arm starts to come naturally back across the body.

The Followthrough

And this may explain another mystery. Pete's followthrough compared to most great servers always ended more to his right side. If you look at his hand it comes down in the middle of his torso, or even at times actually on his right.

I have heard internet instructors claim that this is a great model to follow. Yes, if you are Pete Sampras. And if you rotate your hand and arm faster and hit upward and outward to the ball more than anyone in tennis history.

Pete's followthrough—what does it mean?

It's not that his followthrough is somehow truncated. It's the natural, relaxed deceleration pattern of his incredibly powerful upward, outward motion.

So what if anything does that mean for you as a player? The most basic point is that you should try to complete that internal shoulder rotation.

That's something that many pro players don't do. And the reason they aren't maximizing racket head speed. But I've proven on court that it's entirely possible with players at all levels. See for example the huge impact it made on an elite women's college player. (Click Here.)

And yes, if you can naturally complete that rotation sooner, that will maximize its effect. And yes, if you want a higher topspin component you can try hitting more outward to the ball, more to your right. But don't force it. And don't try to mechanically bend that elbow too soon in your swing.

There is only one Pete Sampras. After 20 years, I am still learning from studying his incredible motion.