If you watched the movie Forrest Gump, you were told to "Never, ever take your eye off the ball." And some really do this. But is this what you really want to do?
Some find that watching the ball constantly helps them focus. And in the short term, perhaps that's best for some players. But you are handicapping yourself if you constantly watch the ball throughout every rally. Here's a breakdown of what you really should be watching during a point. Note that even if you are watching the ball, you can still be somewhat aware of your opponent through your peripheral vision.
- As the opponent is serving. Watch his racket right up until contact. This allows you to see how the racket is moving just before contact, so you can better read the spin. If he does a high-toss serve you might glance up to see how high it goes so as to better know when contact will be made.
- As the ball is coming to you. Watch the ball closely from the time the opponent contacts the ball, including on the serve. On most shots you should watch the incoming ball right until contact. (Technically, you can't do this with most backhand shots since the racket is between your eyes and the ball, but you can watch the ball almost until contact.) Against a fast, incoming ball, you can't really make any last-second changes, so there's no point in watching the ball right until contact - it's better to get a very good look at it as it approaches. This is especially true when blocking against a hard-hit shot.
- After you've hit the ball. (This includes when you serve.) After you hit the ball, there's no point in watching the ball travel away from you. It's far more important to watch the opponent to see what he's going to do. For example, on the forehand side you can often see where he's going to hit the ball by his shoulder rotation. In any case you should be able to see what he's going to do during his forward swing before he contacts the ball. Some players telegraph their shots early; others only at the last second. Adjust to both. If you only watch the ball, then you can't really react to the opponent until after contact, which puts you at a disadvantage.
Now go back and watch Forrest Gump and you'll notice something interesting - he not only watches the ball constantly, but he never even blinks during rallies. That's taking "never, ever take your eye off the ball" to an extreme! We can learn a lot from Forrest's basic humanity, but we probably shouldn't be taking our table tennis cues from him - for one thing, he has awful strokes. He's not actually rallying - he's just going through the motions, with the ball added afterwards by computer. Here's the video (2:55) on how they put together the ping-pong scenes.