Tuesday, March 16, 2004

"I took my eye off the ball."

Have you ever framed a shot and said to yourself, “I took my eye off the ball?” Who hasn’t? But did you ever ask yourself, “When did I take my eye off the ball?” Perhaps you’ve read or heard that you are supposed to watch the ball into contact, or watch the ball hit your strings. Maybe you’ve heard that it’s important to have the ball in focus at contact.

I’ve heard all of those things and even said some of them. Just because people say things and believe things doesn’t mean they’re true. Fortunately we have a method at our disposal for distinguishing assertion from fact -- the scientific method. Carl Sagan called it a candle in the dark. It’s really quite simple to use. The other day I used it to check the validity of the above statements.

I began with the following hypothesis: It is important to focus on the ball at contact.

To test the hypothesis, I designed the following experiment that you might want to try yourself.

1. Repeatedly bounce the ball upwards off your strings (self volley) to roughly eye height.
2. Establish that you can do this self volley with your full field of vision.
3. Next use your non-racquet arm to block your racquet, hand, and arm from your field of vision (while still allowing yourself to see rest of the ball’s trajectory including its peak).
4. Repeat the self volley with your vision occluded as described in step 3.
5. Try varying the amount of the ball’s path you can see, but never allowing yourself to see contact.

I discovered that as long as I could see the ball as it peaked, I had no trouble maintaining the self volley. Conclusion: my hypothesis is wrong.

Then I tried the following experiment to test this hypothesis: If I focus on the ball at contact, I don’t have to see the rest of the ball’s flight path to maintain a self volley.

1. Self volley as in the first experiment using your full visual field.
2. Block your vision of the flight of the ball except for the ball and racquet contact and a foot or so of the ball’s travel above the racquet.

I found this to be extremely difficult. Conclusion: my hypothesis is wrong.

From this further experiments come to mind, but I’ll leave those to enterprising readers to design. I feel pretty comfortable concluding that seeing some portion of the ball’s flight other than the moment of contact is important.

I have to admit that the results of these experiments didn’t surprise me because I’ve played tennis for a long time. I’ve also seen lots of photos of players at contact, and I’ve read the research literature into visual tracking in sports. I have hit plenty of balls behind my back and I can assure you that I don’t have eyes in the back of my head. I’ve also seen countless photos of pros hitting shots in which the pro’s eyes are not focused on the ball and are even closed at contact (Hingis appeared to blink at contact quite frequently). Tough to watch the ball meet the strings if your eyes are closed. I’ve also read studies of tennis players, volleyball players, and baseball batters who have been observed in controlled conditions tracking incoming balls. The players have been fitted with goggles that monitor the focus of the players’ eyes. Except for on rare occasions, none of the players focused their eyes on the ball at contact. Is there a better way to track the ball than the way that these players track the ball? Maybe. The way to find out is to try some experiments like the ones I did. From my experiments we moved one step closer to understanding why people hit the ball poorly by potentially ruling out one reason. More specifically we falsified the age old hypothesis that it is important to watch the ball into your strings.

Now if you catch yourself saying you took your eye off the ball on a mishit, ask yourself “when?” you took your eye off the ball. It may be that you did take your eye off the ball at some critical moment in the ball’s path. But maybe something else caused the mishit, like a sudden movement or a simple misalignment of your racquet. Those things do happen without a vision mistake. By avoiding a fixation on something that isn’t likely to have caused your error, I think you’ll be more likely to figure out what did.

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