As the impresario who ran New York while 18,000 of us marathoned 26 miles through the city's five boroughs last Sunday, Fred Lebow is like no other figure in American sports.

In 1970, when about 170 long-distance runners enjoyed their loneliness by moving unnoticed and unsung through a looping course in Central Park, Lebow was on hand as the race organizer. He peered ahead and correctly realized this was one sport that would not run in place. Fourteen years later, New York's longest-running show has made Lebow -- the director of the nation's largest marathon -- the most influential man in the sport that has most influenced America to get moving.

As the start of last Sunday's caloric explosion, Lebow was in a state ofcontrolled frenzy. Presiding at the toll plaza starting-line on the Staten Island side of the two-mile long Verrazano Bridge, Lebow was ridden with questions. Will the starting gun -- which is a starting cannon -- go off when the mayor yanks the lanyard? One year, it didn't. Will the media flatbed truck get out far enough ahead of the runners so as not to block them? One year, it stalled. Will the milk-horse runners stay to the rear and leave the front rows to the thoroughbreds? Most years, they don't.

On Sunday, Lebow (born Lebowitz in Transylvania 52 years ago) had another worry: Will the New York City Marathon continue to be, as Runner magazine said of it in 1981, "the most spectacular road race in the world, holding a place in sport that is unique and envied."

Some promoters in Chicago, it seems, now claim that their marathon is No. 1. With clever footwork, they staged their event the week before New York. Bankrolled by $1.25 million from the Beatrice Foods Co., the Chicago marathon paid premier runners to compete and offered top-of- the-scale prize money to the winners. The promoters called the race "America's Marathon." Get out of the way, New York.

But Fred Lebow and the New Yorkers need not worry about the upstarts from Chicago. All they have is corporate money. Chicago is still a town somewhere between Milwaukee and Cleveland. If people know it as a running town, it's because of the legwork they do rushing for connections at O'Hare airport.

By staging its race a week before New York and engaging in checkbook promotion, Chicago was able to weaken the quality of the New York field. Champion distance runners are high-performance athletes, but two top-speed marathons in seven days is impossible. Other athletes, like professional football players, can go out every Sunday and it makes no difference. Football is a low- performance sport. With time-outs, huddles, half-times, offensive and defensive teams, and a mere 16-week eason, it is no more than a semi-sedentary form of loafing compared to long-distance running.

The stagers of the Chicago marathon are now chanting, "We're Number One." This windiness from Chicago is presumptuous. It proves nothing more than if a corporation is willing to spread out the dollars, a quality field of athletes can be attracted. What does that do for the sport of running or the improvement of people's fitness?

As running has grown, corporations have been tripping over themselves to get to the self-promotional starting line. Even beer companies, knowing no shame, have put up money for races. The difference between their efforts and Fred Lebow's is stark. The marathon in New York is only one of dozens of running events -- from the Fifth Avenue mile to weekly neighborhood fun runs for newcomer joggers -- that Lebow and his New York Running Club stage. They are year-round supporters of the sport, not one-time show-offs.

Lebow himself is a wondrously eccentric man. He is to running what Bill Veeck has been to baseball: part showman, part prophet but totally self-giving when protecting something as sacred as play. I met him when running my first New York marathon in 1977. He gave everyone medals at the finish line. This year, when most of us ran through the heat for a Personal Worst, the medal came with a ribbon. It was hung over your neck while you staggered through the chutes, half-delirious, half-ecstatic.

When the New York Marathon rose to world prominence and people were saying that it had replaced Boston, Lebow said no, Boston would always retain its specialness. He was gracious and true. The tone coming out of Chicago seems to be saying that Fred Lebow and New York should move over. That used to be known as road- hogging. It still is.