In a fit of honesty shortly after his victory in the Boston marathon, Bill Rodgers said: "Financially, it was important for me to win." He could not have caused much more of a fuss throughout runnerdom had he conspired to mix sand with honey.

Distance runners, from the 11-minutes-per-mile huffers on up, have seen themselves as the last hope of athletic purity. Let others - the football oafs, the basketball freaks, even assorted pole vaulters and sprinters - corrupt themselves and demean sport by accepting money: we will suffer gladly and regard money changers as a breed slightly below yipping mutts.

That always was a comfortable philosophy, for in fact no money was available - at least in the United States - even if some six-miler would elbow everybody off the track to get some. A decade ago the surest sign of insanity was to insist a runner could one day earn a decent living in a running-related business.

A Finn, Lasse Viren, showed the world that was possible in the '76 Olympics. Or did you really believe his feet hurt when, after winning the 10,000 meters, he removed his shoes and held them aloft?

Now Frank Shorter and Rodgers, among others, are moving with Viren-like verve in the U.S. And their fellow runners are aghast.

Wasn't that awful what Bill said after Boston?" one said over the phone.

I thought it was wonderful.

For too long, many athletes have been the most unrewarded workers in America - and all because of a notion - amateurism - that was popularized either by someone rich enough not to become professional or a promoter anxious to keep costs as low as possible.

A teen-age farmer can sell a prize steer at the county fair; a teen-age gymnast can attract thousands of paying fans to an arena, but can accept no money. Shorter, Viren, Dwight Stones and others are able to circumvent the amateur rules for track; a modern pentathlete who accepts money for a magazine article about his sport risks losing his amateur standing.

This is no way suggests that competition for the sake of competition is not to be celebrated. At the recent Cherry Blossom 10-mile race, the age-group winners fondled their prizes, a pair of running shorts, with at least as much affection as some winners of PGA tour events accept $40,000 checks.

Give me the runners everytime. But give those runners with special skills - and the means to exploit them - at least as much chance as anyone else in any other area of life. Do we have amateur truck drivers? Amateur lawyers? Amateur public officials?

Gradually, cracks in this myth of amateurism are beginning to appear. Before Spencer Haywood and the courts settled the matter, it was an unwritten sin for a collegian to sign with a pro team before his class graduated. We have had open tennis for 10 years. Now that the Soviets and East Germans are dominating some Olympic events, it is all right for American businesses to help underwrite American amateur sport.

Hurray.

Once most of sport was reserved strictly for amateurs. But there were temptations, as the purest of golfing's pure, Bobby Jones, discovered.

"When Bob retired from competition," the late Clifford Roberts wrote in his history of the Augusta National golf club, "he made two important commitments . . . that were definitely professional in character. A few people then began asking if Bob were still an amateur, or if he should be classified as a professional.

"The United States Golf Association took the position that it would be improper to make a ruling unless Bob undertook to enter a golfing competition as an amateur. Some of the Royal and Ancient officials of St. Andrews gave voice to their emotional feeling that Bob should always be regarded as an amateur, no matter what he might do."

As usual, Roberts found a way to satisfy everyone. For the first Masters tournament, Jones was listed neither as an amateur nor a professional but as "president, Augusta National Golf Club."

Who is more qualified to advise runners about running than Rodgers? Why should he not be able to operate a shoe store and lend his expertise to whatever innovations are possible in running without being constantly subjected to cries of "Say it ain't so"?

Say it so, Bill. Say it whenever possible.Say it loud and clear, like Shorter, that most of the rules of amateurism are dumb, or at least out of date. Help drive everybody out from under the table.