When Flying Paster came to Pimlico after a 10-length defeat in the Kentucky Derby, trainer Gordon Campbell offered a reason to believe he would improve upon that performance in the Preakness. He said his colt had not liked the "cuppy" Churchill Downs track.

Luis Barrera, the trainer of Screen King, viewed his horse's Derby loss in much the same way. "Screen King was jumping up and down on the track," he said. "He just didn't care for it a bit." Too cuppy.

The trainer of practically every other also-ran at Chuchill Downs has stated publicly that the cuppiness of the track significantly contributed to his horse's defeat. These remarks have prompted several readers to inquire: What, precisely, is a cuppy race track?

Horsemen might say it is a racing surface whose cushion is so powdery or sticky that an animal cannot get proper traction. But there is a more illuminating definition.

"Cuppy" describes almost any track on which your horse was beaten. "The track was too cuppy" is rapidly taking its place alongside "Sorry, dear, I have a headache" as a great all-purpose excuse.

There are, of course, many cases when track surfaces do influence horses' performances significantly. Some horses can't run in the mud; others love it. Some horses prefer running on grass; others don't like it. Some horses love the synthetic Tartan track at Calder Race Course; others never do well on it.

But in the entire history of the sport, there never has been an occasion when a trainer has said his horse likes a cuppy track. This is strictly a negative concept, employed only after a defeat. The track never seems to "cup out" for great horses like Spectacular Bid, only for the lesser animals who chase them.

Discourses on cuppiness are only one of the numerous forms of nonsense a horseplayer must contend with to handicap the Triple Crown races.

Ordinarily we look at the past performances in the cold black and white of the Daily Racing Form, see Horse A defeated Horse B by 10 lengths, and dismiss the latter.

In the Triple Crown series, however, we get to listen to the trainer of B, who would be violating all the canons of his profession if he said, "My horse lost because, alas, he is 10 lengths inferior to A."

Instead, B's trainer will offer his explanation of the defeat, and force a horseplayer to solve handicapping questions he never before has seen. For example: Horse A beats Horse B by 2 1/2 lengths, but the trainer says B hit his head on the starting gate and knocked two teeth loose. Now the horses are facing each other in a rematch. What will the result be?

That was the question when Sham faced Secretariat in the 1973 Preakness. With no dental misadventures at Pimlico, Sham lost again, by precisely 2 1/2 lengths.

There have been many other ingenious alibis for Derby defeats.

Naskra lost in 1970 because he was so agitated by the band's rendition of "My Old Kentucky Home."

Bombay Duck finished last in 1975 after he was hit by a flying beer can on the backstretch.

If the trainers of this year's losers can't muster up a better alibi than the cuppy track at Churchill Downs, Spectacular Bid should not have much to worry about in the Preakness Saturday.