In a first for an event that has already survived the most notorious cheating scandal in running, the Boston Marathon has disqualified two able-bodied competitors for entering the wheelchair race.

"To the best of my knowledge, that's never happened before," said Marja Bakker, a member of the Boston Athletic Association's adjudication committee. The names of the two competitors were not immediately available on Tuesday.

Twenty years after Rosie Ruiz took a trolley to the finish line to temporarily claim the women's title, race organizers noticed the two racers moving around the starting line without any apparent impairment.

"We had some questions before the race, but we had no proof before," Bakker said. "So we cannot disqualify someone before the race."

When confronted, Bakker said, one of the two admitted, "I am not disabled." It was not clear if the other intended to contest his disqualification.

Bakker said she did not know why either entered the wheelchair race, which requires the participant to be mobility impaired and even breaks the entrants into four categories based on the degree of impairment.

"They could be doing it innocently. Perhaps not," said Boston Athletic Association spokesman Jack Fleming. "But the wheelchair division is for people with an impaired range of motion. That's what it's for. We have a division for people who can run."

In the United States, wheelchair sports are limited to those with "any lower limb impairment that prevents you from competing in the able-bodied analog sport," according to Todd Hatfield the program manager of Wheelchair Sports USA, the national co-ordinating body.

Some competitors don't use a wheelchair in everyday life, but the disability has to be permanent. Those who meet the criteria are further broken down based on the level of impairment, Hatfield said.

In Boston, those who apply to enter the wheelchair race are interviewed to put them in the right classification. "The people who work on that aspect really get to know them," Fleming said.

Jean Driscoll, who won the women's wheelchair race this year for the eighth time, said she wasn't offended as much as surprised that able-bodied people -- "A.B.s," as they're called -- would choose to scrunch into the racing chair for more than two hours.

"I don't think they're making light of (disabilities)," she said. "I think it's kind of funny that would want to cramp their legs up for 26 miles. There's a level of comfort you need to be able to do that."

Six to 12 people are disqualified from the race each year -- none more infamous than Ruiz, first woman to cross the finish line in 1980, with a time that was then the third-fastest in women's history. Officials determined that she skipped part of the race and, eight days after crowning her champion, stripped her of the victory.

In 1997, a California couple finished first in their respective age divisions -- seconds away from record times -- but they didn't look tired or sweaty enough to have run a marathon. When they didn't show up on surveillance videotapes that were instituted as a precaution against another Ruiz, they were disqualified.

Neither of this year's wheelchair racers finished in the money. "Certainly if they had come forward and won prize money, a few of us would be up in arms," Driscoll said.

While wheelchair sports are limited to the disabled in the United States, Hatfield said Canada allows the able-bodied to join wheelchair leagues in the interest of growing the sports and "reverse integration."

"A lot of your elite wheelchair athletes say, `Bring 'em on,"' he said. "If they're willing to work that hard -- typically they're carrying some extra weight, because of the legs and so forth -- they might want the competition.

"But I just can't imagine an A.B. wanting to get in and push a racing chair. I cannot see it. Those people must have been very hardcore."