Little more than a month ago, Cure the Blues seemed indomitable. In six of his seven starts, he had demolished his competition; in his lone defeat, he had run so fast, so gamely that he looked likely to become the next American superhorse.

Instead, he has earned another distinction. Rarely in racing history has a horse of such quality undergone such a dramatic turnaround. Cure the Blues was trounced in the Wood Memorial Stakes, finished 24 lengths behind Pleasant Colony in the Kentucky Derby and lost by 17 lengths in the Metropolitan Handicap at Belmont on Monday.

His decline is not a simple case of a horse going off form. Cure the Blues' woes stem from a complex interplay of factors: his training schedule, his physical condition and possibly the relationship between owner Bert Firestone and trainer LeRoy Jolley. The latter is a prime topic of gossip and speculation on the Belmont Park backstretch nowadays.

Jolley inherited some ready-made problems when he took over the training of Cure the Blues this winter from Bernie Bond, who had guided him to five straight victories in Maryland as a 2-year-old. The colt was suffering from persistent foot trouble, which delayed the start of his 1981 campaign and interrupted it on several occasions. Jolley was sometimes forced to play catchup and probably never got to train Cure the Blues in a way he would have considered optimal.

Whatever the reason, Cure the Blues' workout schedule did not accomplish what it was intended to accomplish. Horses with so much natural speed have to be taught to relax, to conserve that speed. When Laz Barrera was training a similarly fast horse, Bold Forbes, in 1976, he said, "To win a race like the Derby, you've got to get the crazy speed out of the horse."

But Cure the Blues' frequent eyepopping workouts -- five furlongs in an incredible 56 3/5 seconds, six furlongs in 1:09 3/5 -- were not going to get any crazy speed out of him. In fact, he became a much less tractable animal as a 3-year-old than he was at the age of 2. When Cure the Blues won the Laurel Futurity last fall, jockey Rudy Turcotte was able to restrain him, let out a notch when he wanted. But whenever the gate opens in front of him this year, the colt seems unrestrainable, his speed uncontrollable.

His all-out running style produced the most dramatic horse of 1981. In the one-mile Gotham Stakes at Aqueduct, Cure the Blues and Proud Appeal battled head-and-head, running a half mile in 45 seconds, three-quarters in 1:08 4/5, the mile in an extraordinary 1:33 3/5. The effort was so gruelling that it took a toll on both horses. Proud Appeal's form since that race has deteriorated steadily.He finished 19th as the favorite in the Kentucky Derby, and trainer Stanley Hough indicated this week that the colt still hadn't recovered.

Cure the Blues hasn't been the same since the Gotham, either. In his next start, the Wood Memorial, he engaged in another all-out battle for the early lead and practically stopped to a walk in the stretch, losing to Pleasant Colony. After his defeat, the second-guessing began.

Bon, who stayed in frequent touch with Firestone, was second-guessing Jolley's training. Firestone second-guessed jockey Jacinto Vasquez, blaming him for the loss in the Wood. And since that time, the management of Cure the Blues has borne little resemblance to the typical work of Jolley, one of the most cerebral trainers in the business.

Vasquez was fired and replaced in the Derby by Bill Shoemaker, whose magical hands guided the colt to a 15th-place finish. The time had clearly come for a tactical retreat; Cure the Blues needed to be rested and recycled. Instead, Firestone and/or Jolley reacted like a poker player chasing a losing hand. In an effort to recoup their losses, they entered Cure the Blues against the toughest older horses in America in the one-mile Metropolitan Handicap. With jockey Don Macbeth riding this time, he waged his now-customary suicidal battle for the early lead and collapsed in the stretch.

Many racetrackers assume that the ill-considered decision to run in the Met, like the ill-considered decision to fire the capable Vasquez, was Firestone's. The owner is an omnipresent figure at Jolley's barn; he is almost always looking over his trainer's shoulder literally and figuratively. Not many people could cope with such pressure and second-guessing, and certainly not the volatile Jolley. His whole stable has been in a slump this year, and it has certainly not been the ideal environment for Cure the Blues to demonstrate what a great race horse he is.