U.S. track star Michael Johnson's bid to become the first man to win the 200- and 400-meter gold medals in one Olympic Games received an enormous boost yesterday, when the schedule for this summer's Olympics was adjusted to put the events on different days.

"I feel real good about it," said Johnson, who is the defending world champion in both events. "It will be a tremendous satisfaction to go into the Olympic Games in my own country to try to make Olympic history."

Johnson, 27, had been asking Olympic organizers and track officials for months to change the schedule so he could finish competing in one event before having to begin the other.

The International Amateur Athletic Federation (IAAF), track and field's world governing body, decided yesterday at a meeting in South Africa to accommodate him, apparently hoping that Johnson's quest will heighten Americans' interest in track and field.

"We believe that the Olympic Games will be great, but will be more important if the United States will have its heroes," IAAF President Primo Nebiolo said via a satellite linkup. "And Michael is one of those heroes. He can become one of the greatest heroes that we have had in athletics."

Under the new schedule, the 400-meter preliminary heats and final will be held July 26-29. After the 400 final on the 29th, all track competitors will have a day off. The 200-meter preliminaries will follow on July 31 with the final on Aug. 1.

The former schedule would have had Johnson competing in the 400 semifinals and the first and second rounds of the 200 on July 29, and the 200 semifinals and 400 final on July 31.

"Changing back twice within one day would be impossible," Johnson said.

Calling the rest day "a bonus," Johnson said of the new setup: "I think it's a perfect schedule."

Carl Lewis -- who, like Johnson, still must qualify for the Games at the U.S. Olympic trials in June -- also stands to benefit from changes made yesterday. The men's long jump was switched from Aug. 1-2 to July 29-30; that would help Lewis's plans to compete in the 100 meters, 200 meters and long jump.

During the satellite linkup, Nebiolo spoke directly to Lewis, 34, who won gold medals in the 100, 200, long jump and 4x100 relay at the 1984 Summer Olympics in Los Angeles.

"I wish you to repeat Los Angeles," Nebiolo said. "You have the possibility now to get four gold medals like in Los Angeles."

Lewis said he was pleased with the changes. "It shows that they care about protecting track and field as well as putting on the best Olympics possible, and I'm excited about that," he said.

Valerie Brisco Hooks of the United States won the women's 200 and 400 meters at the 1984 Games, which were boycotted by a number of countries, including the Soviet Union.

Last August, Johnson became the first man to win the 200 and 400 meters at the same world championships. He has won 51 consecutive 400-meter finals, a streak that dates from 1989, and 17 consecutive 200-meter outdoor finals.

"Winning the double . . . would be a good thing for me and a good thing for the sport . . . {and} put a whole new perspective on sprints," he said.

Johnson said his competitors shouldn't be hindered by the Olympic schedule change and that the new schedule means "more work for me to do. I got eight races during that week. My competitors know that they have four. If I were a competitor, I would be in favor of the change."

Johnson also plans to compete in the 4x400 relay after the 200 meters is over. He said he also would consider running the 4x100 relay.

In another schedule change, the IAAF moved the start of the men's marathon to 7 a.m. Aug 4. It originally had been set for 6:30 p.m. that day, just before the start of the Closing Ceremonies. Officials had been concerned about the heat. Laurie Olsen, a spokesman for the Atlanta Committee for the Olympic Games, said the new schedule would affect relatively few ticket-holders since customers were warned prior to their purchases that the track and field schedule could change. CAPTION: LOOKING TO DOUBLE UP JOHNSON'S CHANCE TO WIN 200 AND 400 ENHANCED BY NEW SCHEDULE Date

New schedule

Original schedule July 26 400 first round July 27 400 second round

400 first round July 28 400 semifinals

400 second round July 29 400 final

400 semifinals,

200 first and

second rounds July 30 Rest day

Rest day July 31 200 first, second rounds 400 final,

200 semifinals Aug. 1 200 semifinals, final

200 final CAPTION: Michael Johnson: "I feel real good about it. It will be a tremendous satisfaction to go into the Olympic Games in my own country to try to make Olympic history."