U.S. sprinter Marion Jones winced, clutched her back and then crumpled to the track in the middle of her 200 meters semifinal heat. As fast as Jones dropped to her knees tonight, so sank the spirits of track officials and the 60,000 fans at Olympic Stadium for the world track and field championships.

Although Jones was carried to the medical area on a stretcher, her injury was later deemed minor: lower back spasms and cramping. Yet she is definitely out of Friday's 200-meter final, and it seems unlikely she will return for Sunday's relay events.

Her sudden departure leaves the world track and field championships arguably without its biggest star of any nationality. And it leaves Jones far short of the lofty goals she set for herself at the start of the year.

Jones wanted four gold medals here, in the 100, 200, long jump and 4x100 relay. Instead, she takes home a gold in the 100, a bronze in the long jump and a back injury. Her next major challenge will be five gold medals at the 2000 Olympics in Sydney.

"I was deeply affected by the injury sustained by Marion Jones, and I am sure that millions of fans around the world share this sentiment," said Primo Nebiolo, the president of the world governing body of track and field, in a statement. "Marion Jones has become a symbol of all that is best in athletics. . . . "

As Jones's meet ended, U.S. decathlete Chris Huffins won the bronze in the decathlon and U.S. hurdler Duane Ross got the bronze in the 110 meter hurdles. Ross ran a personal best of 13.12 seconds, taking advantage of the absence of defending world champion and fellow American Allen Johnson, who bowed out of the event Tuesday with a strained right calf.

Decathlete Tomas Dvorak, the world record holder from the Czech Republic, won the gold and Britain's Dean Macey moved past Huffins in the last event -- the 1,500 meters -- for the silver. Despite losing to Macey, Huffins celebrated by diving into the steeplechase pool and pitching his track shoes into the stands.

Given Huffins's performance at the last world championships, the revelry was fitting. After fouling three times in the javelin throw at the '97 championships, Huffins pitched his track shoes for the first time. Only then, he threw them into a trash can and stormed out of the stadium, quitting the competition.

"I came here not thinking very much about the '97 world championships, even though I knew a lot of people were going to be," Huffins said. "The bottom line for me . . . was that I wanted to leave here with a medal. Gold was the goal, but if I didn't leave here with a medal I probably would have been very, very, very upset with myself."

With Jones out of the 200 final, American Inger Miller becomes the favorite. Miller, the silver medalist in the 100, ran the night's fastest qualifying time (22.17). Miller has been flaunting her recent progress under new coach John Smith, whom she joined in January and who also coaches a host of track and field stars, including Maurice Greene, the world record holder in the men's 100.

"It was good," Miller said after her semifinal heat. "I felt good. I can't talk now; I've got to stay focused."

Jones collapsed about 50 meters from the finish of her race. She came out of the turn looking fine, but suddenly clutched her lower left back and skipped forward a few steps before crumpling to the track. Her husband, world champion shot putter C.J. Hunter, rushed onto the track. Jones lay almost motionless for several minutes before stadium personnel moved her to the stretcher and took her into the medical area. She received treatment from doctors Norman Levin and Stephen Bernabeu. In a statement, her agent said she was undergoing treatment tonight and would be examined further.

"I don't think I'm going to let her compete in the rest of the championships," Jones's coach Trevor Graham told Reuters, but also acknowledged: "She could wake up feeling fine."

"We are a team, and Marion Jones is part of our team," USA Track and Field Chief Executive Officer Craig Masback said. "We have no particular expectations for any of our athletes. She set extremely high expectations for herself. . . . Would we have liked to have Marion Jones in the final of the 200 meters? Of course. . . . But our greatest concern is her recovery."