The split step and the ready position are very closely related, and mechanically speaking the split step is simply a small hop you take while in the ready position.
When you perform a split step and take that small hop, you aren’t looking to get a ton of air. You only want to get about an inch high off the tennis court. What’s critically important is that when you land, your weight needs to come down and load up in your legs. When you come down from your split step, you want the weight to equally compress both of your legs like springs so that you can push off explosively in the direction of the tennis ball. This is much more effective than being flat-footed when your opponent hits you the tennis ball.
Now that we know the split step is mechanically just a small hop, let’s talk about when you want to split step and how you time your split. You want to split step every single time your opponent is about to make contact with the tennis ball. Since you don’t know where your opponent is going to hit it, you need to be able to move in any direction as explosively as possible, and performing a split step is going to allow you to do that.
Timing the split step correctly is slightly tougher than just performing the motion. The key is that you want to be back on the ground, with your weight down and your legs loaded up (so you are at your most explosive) at the exact moment that you realize where your opponent has hit the tennis ball. This of course means that the ball will be well off his strings. Depending on your own reaction time and how hard your opponent has hit the tennis ball, it may be crossing the net toward you by the time you realize where it is going. Knowing that you want to be down and loaded up after your opponent has hit can and should help you time the rest of the motion. Practically speaking, you will generally be just coming off the ground, or in midair, at the precise moment your opponent is making contact with the ball.
Look at the video above of Andrej and me rallying. As Andrej swings forward, I hop into the air. At the moment Andrej makes contact, I’m at the top of my hop. I land as the tennis ball is traveling back toward me and at the instant the instant I realize where it’s headed. When I land, my weight comes down to load up my legs like springs. Now I can move out to the tennis ball explosively and adjust to hit. As I prepare to hit and start swinging forward towards the ball, Andre begins to perform his split step. He’s in the air when I make contact, and when he lands, he knows where the tennis ball is headed and begins to move toward it. Finally, as Andrej again swings forward to hit, I perform my split step so that I am in midair as he makes contact.
Now that we’ve seen the split step in action, let’s take a look at the split steps of a couple different pros on tour. First, we have Radek Stepanek hitting his split. Notice that he’s about an inch off the ground, his knees are bent, his upper body is relaxed and the tennis racket is out in front of him and pointed up. Up next is Tomas Johanssen. If you took his body position here on his split step and just moved him down a few inches onto the tennis court, he’d be in the ready position. Let’s go back to Tommy Haas, and you can again see here that his body position is virtually identical to the ready position while he is split stepping. Tommy Haas is one of the best examples of this on tour.
Finally, let’s take a look at two pros hitting here, Gael Monfils and Marat Safin. Let’s first zoom in on Monfils, and we can see that he’s making contact with the tennis ball. Gael serves very hard, and averages around 130 mph. If we move over to Safin, we can see that at the instant Monfils is making contact, Safin is in the process of hitting his split step and is rising up off the tennis court.
In the next shot of this sequence, Monfils has now hit the tennis ball and it is traveling towards Safin. If we zoom in again on Safin, we can see that even though the ball is about to cross the net, Safin is still at the top of his hop during the split step.
What I want to highlight with this point is that even at an extremely high level of play, where players are pounding the tennis ball at upwards of 130 mph, the returner is not landing and split stepping before he knows where the ball is going. This is critically important, and I want to emphasize this point again: In the second picture of Monfils and Safin, you and I can see quite clearly that the tennis ball is headed down the tee, but this is only because we have frozen the action and can examine it in detail. The tennis ball is traveling 135 mph toward Safin and even though it has almost crossed the net, at this moment Safin might only be beginning to analyze its trajectory. Safin is timing his split so that, when he lands and his weight comes down to load up his legs like springs, he will know where the ball is going, and not before then.