The host role at the Olympic Games brings automatic qualification in all team sports, a mixed blessing designed to boost attendance.

On the positive side, United States teams can focus their attention on the competition in Los Angeles, rather than concerning themselves with the usual qualifying games a year before in frequently unfavorable surroundings. Additionally, assured Olympic participation gives a boost to minor sports normally overlooked by the public.

Perhaps the most determined effort to win by any U.S. athletes in Olympic history has been mounted in women's volleyball. This country last competed in this area of the Olympics in 1968, when it finished eighth and last, but this time there is expectation of a medal.

Since 1975, when former Israeli coach Arie Selinger instituted a year-round training program, the U.S. women have followed an incredible regimen in which they train six to eight hours a day, six days a week, 11 1/2 months a year. Seven team members, including 6-foot-5 Flo Hyman, the 100-mph spiker, have been with Selinger since the beginning, training first at Colorado Springs and now in southern California.

Last fall, the team was beaten by host Peru and finished third in the World Championships. Feelings about that fluky result, after a sweep of the preliminary pool that included powerful China, led Selinger to criticize U.S. participation in the Pan American Games.

"If they don't win a medal (in Los Angeles), after all they've put into the program, it could be hard to deal with," said Damien Wooles, spokesman for the U.S. Volleyball Association.

The men's volleyball team, 13th in the last World Championships in Argentina, is somewhat less dedicated. Based in San Diego, the men under Doug Beal are subsidized by a job program in which they work four hours a day but are paid for eight and spend that extra time practicing.

The field hockey situation is similar, with a strong, motivated women's team hopeful of a medal and the men merely seeking respect.

The U.S. women, ranked third in the world, relocated to Philadelphia in January 1981 and have trained there since under Coach Vonnie Gros. Gros has rotated many of the squad of 32 in various international events and the final Olympic squad of 16 will be selected at the National Sports Festival in Colorado Springs.

Like the volleyball team, the hockey club is trying to rebound from disappointment, as it proved a dismal flop in the World Championships in Malaysia. There were mitigating factors; for one, the scheduled lighting system was not installed and three times the United States had to play afternoon games in 95 percent humidity with temperatures as high as 124 degrees.

The U.S. soccer team is training in Florida and will participate in the President's Cup in Seoul, South Korea, in June. Its Pan American Games participation rests on the outcome of a home-and-home series with Canada in early July.

John Stollmeyer of Annandale, Va., and the University of Indiana is one of the top U.S. players. Among the members of the National Youth team are five Marylanders--brothers Rich and Rob Ryerson of Laurel, Mike Brady and Scott Snyder of Bethesda, and Bruce Murray of Germantown.

Only once, in 1904, has the United States won a medal in soccer. Its last Olympic venture, in 1972, proved winless. Next year's 16-team competition will begin with pool play at four sites, including Navy-Marine Corps Stadium in Annapolis, with the top two teams in each pool advancing.

Team handball is popular in Europe and Eastern European countries swept all six medals at Montreal. So the U.S. teams will be facing the best when they tour Romania, Bulgaria and Hungary in July. Other European tours are planned for October and May 1984 for both the men's team, coached by Spaniard Javier Garcia Cuesta, and the women, guided by Czech Klement Capliar.

As usual, the composition of the men's basketball team will depend on the inroads made in the available talent by the National Basketball Association. Only in that controversial Munich final in 1972 has the U.S. failed to win the gold medal.

Women's basketball made its Olympic debut in 1976, when the United States captured a silver medal behind the Soviets. Pat Head Summitt, a member of that team, is the coach this time and will guide the U.S. entry in the Women's World Championships in Brazil, July 24-Aug. 6.

The U.S. will be trying to maintain a tradition of excellence in Olympic archery competition. It swept the gold medals in both 1972 and 1976; in 1980, scores at the U.S. Trials were higher than those in Moscow.

Another area of U.S. strength is shooting, especially shotgun and rifle, and there will be 11 events at Los Angeles with the addition of a separate women's competition for the first time.

The United States has not won a cycling medal since 1912, but Ed Burke, technical director for the U.S. Cycling Federation, sees a good possibility now of a breakthrough.

Key points in this country's favor are the enthusiasm created by the Games being in the U.S., with a resulting increase in indoor facilities, and the addition of a women's event for the first time.

Rebecca Twigg, the world champion in pursuit, and Connie Carpenter, a three-time medalist in the World Championships, are the leading U.S. contenders in the women's road race.

Best chance among the men rests with Leonard Nitz, 1981 World Championships silver medalist in the points race, another new Olympic event.

Although women's judo will be contested in the Pan American Games for the first time, Olympic competition still is confined to men.

The Los Angeles Olympic Organizing Committee is distributing pins for each event, but the canoe and kayak number has found no buyers among members of the American Canoe Association. It shows a whitewater boat and there are no whitewater events at Los Angeles, because the organizers declined to bear the cost of the necessary facilities.

While the United States always has performed well in whitewater competition, it is less accomplished in flatwater events, with their emphasis on strength and repetition.

With the association headquarters in Lorton, many of the top competitors reside in this area. Theresa Haught of Arlington and Linda Dragan of Washington are members of the U.S. elite kayak team, while Dave Halpern of Washington and Dan Schnurrenberger of Silver Spring are on the A team. Barry and Bruce Merritt of Ridge, Md., are on the A canoe team.

Although the U.S. has not won a modern pentathlon medal since 1964, hopes are high this time. Robert Nieman became the first U.S. pentathlete to win a world title in 1979, the same year the U.S. took its only team championship. Michael Burley, ranked third in the world in 1982, is another good possibility for a medal.

Among the contenders for the other two berths on the U.S. team, which will compete in the World Championships in West Germany in August, are Robert Stull of Damascus, Md., and Michael Storm of Arlington, Va., a world team member in 1982.

U.S. fencers last won an Olympic medal in 1960 and placed no higher than seventh in any event at Montreal, so there is considerable room for improvement. Unlike most Olympic sports, fencing will not conduct one trial but will determine its Olympic team on results of five trials, because of the importance of consistency in the sport.

Although the U.S. no longer dominates rowing, there is reason to expect at least a couple of medals in 1984. The women, who had dreamed of gold before the 1980 boycott, still rank high.

Lee Kemp, a three-time world champion, is the top U.S. hope for a gold medal in freestyle wrestling. The United States usually fares well in freestyle and captured one gold, three silver and two bronze at Montreal. However, no U.S. wrestler has won an Olympic medal in Greco-Roman.

In equestrian competition, the U.S. is strong in jumping and three-day eventing, weak in dressage. The World Dressage Championships proved a disaster in 1982, when the U.S. team placed 10th among 11 and no individual finished in the top 20.

A good look at U.S. prospects can be gleaned from the World Three-Day Event Championships, to be contested at Lexington, Ky., June 3-5. For jumping, area fans can get a ringside seat, since the Washington International Horse Show is a major determinant in team selection.

At least four weightlifters are given medal chances--Curt White, Ken Clark, Jeff Michels and super heavyweight Mario Martinez.

Four Olympic yachting classes--470, Star, Soling and Windglider--will be among the eight competing in the Pan Am Games. Those four, as well as the other three--Finn, FD and Tornado--will test the Olympic facilities at Long Beach in a regatta scheduled July 30-Aug. 6.

The U.S. traditionally has done well in yachting, with 11 gold medals through the years, but it managed only two silvers and a bronze at Montreal.