I could win the Boston marathon next year. I weigh 200 pounds, have never run a step more than 10 kilometers nonstop or one mile faster than 7 1/2 minutes. Nor do I intend to drastically alter the sort of training that makes such mediocrity unalterable. All I said was that I could win the Boston marathon, not run it.

Yes, a relative slob could win the most prestigious race in long-distance running. Perhaps someone a bit more fit and dedicated than myself, for whom Nike would seriously consider paying serious money not to wear its shoes.

But an emaciated-looking fellow, a Kent Tekulve when his curve goes straight, might well pull it off. A woman would be a cinch. A woman could win Boston without breaking much of a sweat.

Rosie Ruiz might already have done it.

It certainly is premature to insist that she was not the best woman in Monday's Boston marathon, as many runners and officials already are. She may be the running phenom of the ages, a 5-foot-8 machine who trains like ordinary folks and then runs the shorts off the snobs in all the important races.

If what she did is legitimate, Rosie Ruiz will be our next sporting heroine, fit for the covers of every magazine that matters, more marketable than any woman athlete in history. We'll have the book in a month, the movie in a year, an entire line of Rosie Ruiz running garb spilling off the shelves.

But no Latin-looking starlets are beginning to jog just yet, for a good deal of evidence -- circumstantial as it might be -- suggests that while Rosie Ruiz crossed the finish line before any woman in Boston, she did not run the entire 26 miles and 385 yards.

It suggests that if Rosie Ruiz is going to write a book the title ought to be: "How I Bamboozled Sport's Greatest Spectacle." That might be enough to assure a tidy income, a permanent niche in our mind.

Capers more darling have been tried with less incentive.

The tell-tale sign, everyone agreed, was that she did not appear to be near death when she crossed the finish line, as all runners are supposed to be after such an ordeal in the noon-time sun.

"The second I saw her, I was skeptical," said the male winner and America's Marathon Man, Bill Rodgers. "I know a top runner when I see one. She didn't look tired . . . but to go from 2:56 to beating Patti Lyons and Jacqueline Gareau, I'm sorry."

In her second marathon, Ruiz allegedly ran the third-fastest time of any woman in recorded history -- and a staggering 25 minutes faster than what she ran six months ago in New York. It is a fact not easily swallowed, for it would be a quantum leap in a sport where a minute or so of improvement at the highest level is regarded as cosmic.

Which leads to an even more intriguing question: did Rosie Ruiz even run in the New York Marathon? Might she have broken three hours by slipping onto the course, tagging along and using that phony 2:56 to qualify for Boston?

The race director for the New York Marathon, Fred Lebow, said yesterday that when Ruiz submitted her application, she said she anticipated finishing in about 4 hours and 10 minutes -- or about an hour and 20 minutes slower than her recorded time.

Was this the ultimate sandbag?

There were 125 runners who tried to get onto the Verrazano Bridge Plaza (for the start of the race) and 100 succeeded," Lebow said. "forty jumped into the race in Brooklyn, 20 were diverted at the Queensboro Bridge.

"Another 72 late starters were stopped 200 yards from the finish line. Eight runners with high numbers (the slower entrants) attempted to stand in front of the (start) line. One runner was disqualified for instituting a false start. Six were caught for cutting the course.

Eighteen wore another runner's number. Twelve gave their numbers to someone else. Two used false names to obtain numbers. Twelve lied about past marathon performances . . . Nine were recognized by video machines as unofficial runners and three were charged with unsportsman-like conduct."

So it clearly is possible for someone with a mind to deceive the New York officials. And much of the charm of Boston is all manner of characters being able to sneak onto the course.

Women, in fact, had to sneak onto the course just to run until recently. They still are considered too delicate to run any distance beyond 1,500 meters in the Olympics.

But for a decent amount of time, an impostor fooled Olympian officials in the marathon at Munich, crossing the finish line and basking in the glory before the hoax was exposed and Frank Shorter declared the winner.

If the latest Boston marathon becomes known as The Ruiz Ruse, it creates fascinating possibilities. Because no marathon can be totally policed and totally filmed within reasonable cost, future headlines might read: "Obese Farmer Sets Marine Corps Record."

Or look several years hence, when the athletic world staggers into Reality and begins to openly pay runners for their order of finish in important marathons. The temptation would be overwhelming for a world-class runner to slip into a glut of colleagues after five miles or so and almost be assured a healthy check.

Who could have imagiined a once-elite, lightly-regarded sport possibly encouraging larceny for profit?