Alberto Juantorena. Cuban double gold medal winner of the 1976 Montreal Olympics, will compete in the United States for the first time Sunday in Los Angeles.

He says he is out to break his own world 800 meter record this track season.

The runner, renowned for his graceful, gazelle like style, was interviewed during one of his daily three hour training stints here.

Juantorena broke his own world record in 1977. It stands at 1:43:44 and he hopes to lower it to 1:43. Asked if Los Angeles might be the place, he answered, "I don't think so. It's not the time. It will be my first competition of the season.

"I'm happy to be on the first Cuban track and field team that is going to the United States since 1959. What is most important is that I can expect some good competition and, besides, it will be good for relations between the people of Cuba and the United States."

Juantorena is 28, married, with a 4-year-old daughter and a 1-year-old son. His wife is a physical education teacher and he recently decided to follow her footsteps, although he is a third-year economics student at the University of Havana. Both are members of Cuba's Young Communist League.

Juantorena trains by running on sand, on hills and on the track. He says he feels in excellent condition for the heavy schedule of the international track campaign which includes the Pan American Games in Puerto Rico in July.

"The key to running the 800 in 1:43 flat," he said, "is to have good competition and also to be favored by the wind."

Juantorena expects to run both the 400 and 800 meters this season. He won gold medals in both events in Montreal but his 400 meter time is well off the world mark. He will run the two distances in the 1980 Olympics in Moscow, he says, and then switch to 1,500 meters to round out his running career.

Alejandro Casanas, the Cuban Olympic hurdles champion, who until recently held the 110 meter hurdles world record, also will run in Los Angeles.

His mark was broken by Maryland's Renaldo Nehemiah in San Jose, Calif. last Month. Casanas says that the fact that Nehemiah broke his record so early in the season means that, "I will have tremendous incentive to win my record back."