But you know what? Roddick may be the exception. When we look at Andy's motion in high speed video, there are significant differences in the biomechanics of his motion, compared to other top servers. These technical differences may help to account for his supersonic delivery, and his ability to combine new levels of ball speed with heavy spin. Whether other players should copy these elements or not, well, that is another question. We'll address that at the end.
| The technical elements of Roddick's serve are what make it so unique. |
Let's take a look at his serve from the ground up and in particular, at three factors. The first is his serving stance and the related leg action as he goes upward to the ball. The second is his body turn. Third, is his swing path. This is where we get to the invisible part.
We can see that Roddick has a different wind up, that much is obvious. What the high speed video shows is that Roddick also has a different swing path upward to the ball. This variation in the racket path would be difficult, if not impossible, with a conventional windup. For all the talk about Roddick's motion pro and con, these differences have gone completely unrecognized by coaches and commentators. This is because they happen so fast. they are literally invisible to the human eye. They are too fast for TV cameras and other standard speed video as well. It takes a much higher frame rate to see them. But the differences magically appear when you look at his motion at 250 frames per second.
The video also reveals that the overall timing of his motion is different than other top players. These differences are all interrelated and part of a new biomechanical synthesis. When we look at them together we can see his racket-head speed as it develops literally frame by frame.
Stance and Legs
| Roddick's narrow starting stance makes a difference in the way he uses his legs in the serve. |
Let's start by taking a look at Roddick's stance, and let's see how this is related to the use of his legs. Unlike the supersonic movement of his hand and racket around the contact, these elements aren't invisible, but you do have to look closely to see them with the naked eye. All the top players have some differences in their stances, many of which are idiosyncratic or ritualistic and/or irrelevant to the actual bio-mechanics of their motions. But with Roddick, his narrow starting stance makes a difference in the way he uses his legs in the serve.
Roddick starts with both feet almost parallel to the baseline, with the front toe at a slight angle. What makes this different is that the feet are only a few inches apart. The back, right foot is also offset behind about 6 inches to his left. It appears that the tip of the toe of his back foot is roughly lined up with the middle of his front ankle. I don't think we've filmed another player with a similar stance. But what is more unusual is what happens to this stance as the motion starts.
At the start of the motion, Roddick does something I've never seen in a high level player. He moves the front foot backwards, narrowing the stance even further. Just as the knees are starting to bend he picks up his front foot off the court and actually steps back probably 2 or 3 inches. At the same time he turns the heel slightly backward on an angle. The heel of his front foot is now no more than a couple of inches from touching his rear shoe. Maybe you've noticed this movement watching Andy play. But when you see it for the first time, especially on video, it looks bizarre.