I've met just one too many people with the new macho-sport mentality. These fanatics are men and women who can run farther, ski better, swim faster, bicycle longer, serve harder -- and are dying to prove it.

My first exposure to this new attitude came the day an old college girlfriend decided to teach me how to play tennis.

There I stood on the court, wearing a Camp Ken-Etta-Wa-Pec T-shirt, a pair of cut-off Levi's and a Philadelphia Phillies baseball cap. I was prepared to enjoy myself. She almost died of embarrassment. "The first thing you have to do is learn how to dress properly," she said.

After running off to a tennis boutique and paying good money for things like a Rosie Casals plutonium racket, Bjorn Borg gut strings, John Newcombe tennis shorts, Martina Navratilova socks, Ilie Nastase tennis balls, a Jimmy Connors headband and Billie Jean King all-pro tennis shoes, my girlfriend finally decided that I was ready to learn the game.

Back on the court -- where I felt like a walking identity crisis wearing clothing stamped with everyone's name but my own -- we started to hit the ball back and forth, and I was actually enjoying myself. Then the game turned ugly. My charming teacher started to play like a vicious killer, hitting shots I couldn't possibly return, apparently getting some kind of deranged satisfaction from running me ragged.

After 25 minutes had passed without my returning a single ball, I decided to announce my retirement from the professional circuit. And I dismised it -- and her -- from my mind.

Unfortunately, I had a similar experience with a skiing macho. You know the type. The tall blond guy who sits around the ski lodge like an aging side of beef, telling stories about the time he skied out of an avalanche in Colorado and managed not to spill any beer.

Against my better judgment, I decided to let such a man get me out on the slopes. Once again, we started with the proper gear: the right bindings, poles, mittens, boots, after-shave and goggles. When my friend showed up wearing a ski cap emblazoned "Head" I figured it didn't speak too well of his overall intelligence that he had to label his extremities. I also figured that I could probably make a fortune selling "Foot" boots.

We go to the top of the mountain, and my ski instructor was off down the trail two seconds later at high speed. "How do I get down from here?" I shouted.

"Watch," was all he replied from halfway down the slope.

Before he disappeared, I was treated to his imitations of Jean-Claude Killy; he was teaching me by doing things so complicated that even the Olympic Committee would have been impressed. I did the only sane thing and taught myself how to ski.

I haven't seen that friend lately, either. I've considered fixing him up with the woman who taught me how to play tennis. They'd be the perfect couple.

No matter what athletic activity I've taken up, I've encountered extremists. Or, like my experience with tennis, I'd have a friend offer to teach me how to play some new sport, only to learn that his real motivation was to boost his ego by blowing me away.

What possesses people to act like sports machos? What turns my best friends into homicidal killers on the tennis court? Why can't people be content to have a good time?

I can understand why someone like Pete Rose with a multi-million-dollar baseball contract might decide to take baseball more seriously than I; why Tom Watson might be more serious about his gold game. But why is it that since age 6, all of my gym coaches (and many of my friends) have done everything possible to prevent sports from being fun?

More important than how it all started, however, is how to recognize and protect yourself from sports machos. The signs are 1) a need to own the latest status athletic gear; 2) the ability to turn any contest into a death-grip fight to the finish; 3) a decided preference for Gatorade; 4) frequent references to how much pain you can endure, as in "I think 100-degree weather is the best for marathon running"; 5) a sincere belief that "I'm holier than you because I'm in better shape than you"; and 6) a habit of describing how jogging, bicycling, yoga, rowing, hiking or even javelin-throwing cured their marital crisis, career problems or leaky faucets.

My own first tendency in dealing with these people is to punch them in the nose, but I did come across something more subtle recently. Laurence Korwin, author of "You Can Be Good at Sports!", urges counter-attack.

Next time one of those lumbering mounds of self-assurance (male or female) comes over at a party and says something like, "I run 37 miles a day before breakfast," Korwin suggests you counter with something like, "That's nothing. I hear the Taramara Indians run 100 hundred miles a day. Without shoes. Care for some cheese dip?"

Next time an endurance macho grabs you -- the kind who shuns air transportation and swims to England instead -- you're bound to hear something like, "It's no good unless you push yourself past the pain threshold. Then it feels great." Counter with: "Why not stay home and pound nails with your hands? Or maybe beat your head against the wall. That way you don't even have to leave the house."

But I prefer to be a little more direct. I repeat, frequently, the line I used to my tennis racket-wielding ex-girlfriend: "You have a great backhand. But your mind needs some work."