With Olympic-style fanfare and hopes that improved political relations might follow, Olympic officials of the United States and Soviet Union today signed an agreement that signaled an upswing in the sports climate between the two superpowers.

The "Accord of Mutual Understanding and Cooperation in Sports," agreed to amid smiles and handshakes, provides for exchanges of U.S. and U.S.S.R. athletes, coaches and officials and training-camp visits leading up to the 1988 Summer Games in Seoul. U.S. officials are hopeful the agreement will lead the Soviets, who did not participate in the 1984 Games in Los Angeles, to take part in 1988, but Soviet Olympic officials here today said that decision would be made much closer to the event.

Nevertheless, International Olympic Committee President Juan Antonio Samaranch, who attended the signing here at the site of the 1987 Pan American Games, noted that "sometimes sports and Olympism demonstrate that even countries that are very different have very much -- very much -- in common. The most important thing for me is that we are working not only for sport, we are working also for peace."

U.S. Olympic Committee President Robert H. Helmick, who signed the accord for the United States with USOC Secretary General George D. Miller, said that "as a private citizen" he had observed that an easing of sports relationships often signals improvement in other areas. But Helmick said he had not discussed this agreement "with any member of the government."

Marat Gramov, president of the Soviet Olympic committee, represented the U.S.S.R. along with its No. 2 Olympic official, Vjacheslav M. Gavrilin. Gramov told an audience of about 750 attending the signing at the Indiana Convention Center, "Let's have a friendship. Let's leave in peace.

"It's for the benefit of the whole mankind, the whole world."

The first scheduled exchange will take place next September or October, when three Soviet training center officials will visit the United States for a week. Three USOC officials then will visit the Soviet Union, but that date has not been set.

Delegations to follow include those concerned with sports medicine, coaching, training methods and administration of training centers. Observers from each nation will be sent to amateur sports events in the other country. Visits by athletes are expected to be run by the sports' national governing bodies, according to the USOC.

Officials from both countries sidestepped questions about an absence from the agreement of a definite Soviet Union commitment to participate in the 1988 Games. Helmick called the accord "an important historical signing" and "a giant step forward" toward Soviet and other countries' participation. Gramov said the document "continues relations between our two countries and Olympic committees."

The negotiations that resulted in today's agreement began in May 1984, just before the Soviets announced their boycott of the Los Angeles Games. The talks were revived in April of this year, and went well from there, according to Helmick.

"We had a dream, the sports people of the Soviet Union had a dream," he said. "The athletes of (all countries) could meet regularly and throughout the world in friendly competition year after year without interuption . . .

"It took only two meetings over several months to arrange the broad details of this agreement. There were no insurmountable hurdles; there were no details that could not be gone through or around with people who are of the same mind and same objectives . . .

"The importance of this paper is that it represents the first occasion of the sport people of our two great nations to pledge their support to each other and our dream.

"That dream is shared by Olympic committees throughout the world."

The signing took place following national anthems at a huge and highly polished desk that reportedly cost the decorator of the room $6,000. Several pens and numerous signatures were required on the sets of documents written in two languages. Five young girls presented bouquets to the participants after the signing. An exchange of toasts followed, and then the Soviet officials headed for Colorado Springs and a tour of the U.S. Olympic complex.

If no one could say precisely what effect the accord will have on Soviet participation in the Games, Samaranch said, "We hope that his will create an atmosphere that will bring all the countries together again . . . This 'Indianapolis Agreement' will be a very important chapter in the history of the Olympic movement."