I stepped on a tennis ball this summer while running for another ball. I wouldn't mention if except that Time magazine did a piece on people over 40 who still think they are youngsters when it comes to sports. They ran 3 picture of me in a leg cast (I had a badly sprained ankle) and they called me a "klutz," which means a klunk who doesn't know what he's doing.

Naturally, I was offended, because Howard Cosell has said on my occasions that my performance on a tennis court could only be compared to Nureyev's on a ballet stage.

The problem with having any kind of sports injury when you're over 40 is not what it does to your body or even to your pride. It's the flak you have to take from well-meaning people who keep asking you what happened.

Since I was in the cast for six weeks, I was able to break these people down into categories.

In the first category were those who demanded to know why I stepped on the tennis ball. My stock answer for them was: 'I always wanted to do it but I never had the nerve. It beats the hell out of ballooning, because when you're flying through the air you have a complete sense of weightlessness."

The second category of sympathizers I ran into would ask. "Why didn't you move the extra tennis ball off the court before you started playing?"

"Because that would have taken the fun out of the game," I would reply. "The thrill of tennis is to get the ball back without stepping on the one you left on the court."

I said this would so much conviction that most people would reply, "I didn't know that."

"Of course. Why do you think you play with three tennis balls? Pou need two to serve with, and one to leave on the court so you can trip over it."

The real agony of being in a cast is that you have to listen to everyone else's cast story. I don't believe I ran into one person who hadn't been in a cast at one time or another. And when you're on crutches, it's very hard to move away when someone starts telling you this or her own tale.

They were all horror stories and ranged from the fact that their bones hadn't been set right and had to be set again to how they were driven up the wall when their injured leg started itching and they had to poke knitting needles down the cast to get relief.

"The worst thing," one lady told me, "is that when they take the cast off and you see what your leg looks like, most people faint."

After a while I realized that people were not impressed with how I was injured, so I devised a story which would get their attention.

When, asked what happened, I would say. "It's very boring, but if you're really interested - I was on a tennis court, and suddenly this flying saucer landed by the net and a little green man dot out wielding a laser pistol. He said, 'Take me to your leader.' I didn't know who to take him to - so he shot me in the leg."

You would think that your own orthopedic surgeon would have sympathy for someone over 40 who had suffered a sports injury. But when I returned to Washington and went to my doctor to have the cast removed, he took one look at my leg and all he said was. "Did you have a nic summer?"