In any other sport, a competitor who rises from mediocrity to become a star is hailed for his perseverance and achievement.

But at the race track, a trainer who does the same thing will evoke dark suspicions that he is using some undetectable drug or has found some other illicit edge. And so even Tommy Caviness' friends wonder about the reasons for his remarkable recent transformation.

For most of his nine years as a thoroughbred trainer, Caviness has been the equivalent of a .250 hitter in baseball: respectable but unsensational. At times, he became so discouraged by his lack of progress that he wanted to quit. And then, almost overnight, he started to outshine the most astute members of his profession in Maryland. With his modest-sized stable, he was the fourth-leading trainer at Bowie last winter, winning with 26 of the 70 horses he saddled, an incredible percentage. At Pimlico, he has won with nine of his 28 starters.

How do you explain it? Caviness knows the cynics will never relinquish their suspicions, but he insists: "There's no juice (illegal drugs). I've accumulated knowledge over the last nine years and, to be honest with you, I think I've finally put everything together."

Certainly, Tommy Caviness has experience. He started working at the Maryland tracks 15 years ago, first with the idea of becoming a jockey, then as assistant to Dick Dutrow, the best horseman in the state. When his cousin, Baltimore businessman Thomas Pappagallo, asked if he wanted to train a few horses, Caviness went out on his own.

"I do like the game," he said, "but for a married man with four children, it's very, very difficult. I've had one week of vacation in the last 15 years. Many times I was discouraged and wished I'd gone into another profession." Two years ago, in fact, Caviness made the painful decision to enroll in a real estate course, painful because it was an acknowledgement that he was not succeeding in the business to which he had devoted his life.

Even though he was discouraged, Caviness continued to work hard and to try new ideas. This winter, he started computing speed figures and found (as most bettors do) that they gave him a much keener understanding of horses' abilities. "When I look at a horse's figures, I determine whether to run him back at the same level, raise him or drop him in class. I look at horses who have been going long and try to do a figure for the three-quarter mark and decide whether they should be sprinting."

He started to pay closer attention to the soundness of all the claiming horses in Maryland, looking at them not only when they left the paddock but also when they came back from a race. "That's the single most important thing," he said. "It's difficult to train a sore horse."

On a racing circuit filled with trainers who are expert at the claiming game, Caviness began to show that he could compete with the best. He took both Jake's Springer and Literary Art from King T. Leatherbury, stepped them up in class and won. He claimed the router Mrs. Joe Who from Ron Alfano for $14,000, entered her in a sprint and won an allowance race. He was making all the right moves.

One of his contemporaries in the training profession understood what was happening to him. "Tommy's always had the ability and he's always worked hard, and finally he's on a roll," the friend said. "You start doing everything right and it snowballs. Your owners give you more latitude. Your help becomes more conscientious. You're more attentive and confident. When Tommy wakes up in the morning, he probably can't wait to get to the barn, can't wait to look at his horses, can't wait to read the condition book. Right now, he's hungry and he's got the eye of the tiger."

There are many trainers who have, for one reason or another, similarly become overnight sensations, and then just as quickly have faded back into oblivion. Caviness still has to prove that his current success is more than a short-lived hot streak. But he is not worried.

"I don't think this is temporary," he said. "I think I'm on the way."