08/26/2003 12:00AM

American Son fits turf marathon


CHICAGO - Six furlongs is the standard operating distance of American horse racing. Double it, and you reach a land rarely traveled by Thoroughbreds in this age.

But this is the place Arlington is headed Thursday, when first-level allowance horses run a mile and a half on turf, the highlight of a nine-race program here.

The trainer Mike Stidham hand picked this spot for American Son, who won his maiden here July 30 in the second start of his career. There was a recent one-mile grass race American Son could have tried, but Stidham has earmarked this colt for distance races.

“He’s a lumberer, but I think he’ll lumber around there for a mile and a half, while some of them are getting tired,” Stidham said Tuesday.

Owned by the Cobra Farm of Gary Bisantz, American Son is by Royal Academy and out of a Bates Motel mare, a miler’s pedigree. But pedigree does not tell all. American Son debuted here July 3 in a two-turn turf race and wowed some observers with his, well, strangeness. He is a strapping horse with a long, regular stride. Acceleration comes for him in furlongs, not feet. His maiden win nearly a month later represented a big step up, and the added ground Thursday could propel him forward again.

“They can either go that far or they can’t,” Stidham said. “The ones that can inherently go that far make it look like they’re the fittest, but it’s not that.”

The way a horse moves determines in great part how far he will effectively run. An efficient stride helps conserve energy. But part of the equation also is mental. No matter how much physical stamina and stride efficiency a horse may have, if he is not willing to relax early in a long turf race, he will have little left in the tank for the finish.

American Son will have to improve to beat False Promises if that horse continues his solid efforts in turf races. Trained by Tony Granitz for David Maricich, False Promises has finished second in three of four turf starts, beaten a neck or less each time. He is by Jules and out of a Storm Bird mare, and should be decently suited to the extended distance.

The horse with the best 12-furlong grass pedigree might be Bien Blushing, though he has never even tried a turf race. Bien Blushing is by Bien Bien, who was a top turf marathoner during a highly successful racing career.