October-November 2004 --
Question: At the recent USPTA World Conference, I heard you speak on the biomechanics of tennis. During the presentation, you showed a video and briefly mentioned the crossover step in serving versus when the front foot comes in first. Could you explain what happens mechanically in these two movements?
Answer: In this column I will not be able to treat this with an in-depth analysis of what happens in the two serving footwork techniques, but I will attempt to summarize what we know.
Let’s begin by describing the movements so we at least start from the same place and work from there. The crossover motion occurs when the back foot of the server comes forward into the court first, whereas the “front-foot-first” maneuver is just that; the front foot lands in the court first.
When a player uses the crossover step, you can easily see the hips rotate around in the direction of the service motion, thus making total body rotation an integral component of this action. When the front foot comes in first, the body rotation is not as evident. This is not to say that there is no rotation, just that the body’s rotary action isn’t as easily seen and may not be as much as when the crossover step occurs.
In the crossover step serving action, force is transferred from the ground through the leg drive, then through hip rotation, and the force continues its path upward into the trunk. As the trunk nears peak velocity, the opposite arm comes across the trunk, causing the trunk to decelerate. This deceleration causes the upper limb to accelerate at all joints, bringing the racquet into its peak velocity toward the impact zone.
Interestingly, the same occurs when the front foot lands in the court first. It’s just not as evident. All the body parts as described earlier follow similar actions, so what is the differentiating factor between the two motions?
On the crossover step, the primary power sources are the leg drive, hip and trunk rotation, and upper limb action. Again, the same is true of the “front-foot-first” action but the amount of contribution varies between the two. More hip rotation is readily apparent in the crossover and the “front-foot-first” action seems to utilize more leg drive.
At the pro level, Boris Becker did quite well with the crossover step, but you simply don’t see as many crossover steps at the top levels of the game. Why? The probable answer is that with greater leg drive, the pros get more velocity and create a bigger weapon with the serve. I have high-speed films of Ivan Lendl, for example, when he was 19 and using a crossover step. His serve was very good; he even made it to the Masters that year. However, I also have films of Lendl later in his career when he changed his footwork action on his serve to the “front-foot-first” movement. His already good serve became a major-league weapon. And, to top all of this off, even Boris Becker occasionally served using the front-foot-first technique, probably giving him a little extra leg drive and power on his serve.
What about teaching the two different forms of serving? Obviously, if you work with high-level players, you should take a look at the front-foot-first method and work with them on their leg drive into the serve. However, is this action appropriate for all levels? Maybe, but I would caution you that if you work with lesser-skilled players who may not have high levels of coordination, the front-foot-first method might (I said might) be too difficult, whereas the crossover step enables a person to use more body rotation in bringing the racquet toward a high velocity at impact. In my opinion, the crossover step could help a beginner learn to serve more efficiently.
Whatever you choose will, at the end of the day, depend on your preferences in teaching. Perhaps an understanding of what happens in these two motions can further help you in developing your players to maximize their talents and skills, thus getting greater benefit from the game.
Send questions to jgroppel@LGEPerformance.com.
