A field of world-class wrestlers, many of them members of the U.S. Amateur Wrestling Team, are included among the 20-man teams from each of the four branches of the military that will compete in the 1986 Armed Forces Wrestling Championships, which begin today at Larson Gymnasium in Quantico, Va.

The first two days of the tournament consist of freestyle competition, which begins today at 12:30 p.m.

The Greco-Roman events, in which competitors concentrate on the upper body for scoring points, start Wednesday at 1 with the finals Thursday. The competition will follow international rules, with wrestlers eliminated after four losses.

The Marines Corps squad, winner of the last eight team titles, features Greg Gibson, the 1984 Olympics Greco-Roman silver medalist and current World Cup champion who will compete in the 220-pound class. Gibson, 32, has overcome a pinched nerve in his neck and right shoulder that bothered him during the Olympics and probably is in the best shape of his life, according to his Marine Corps coach, Sgt. Art Williams.

"Now that he knows he's fully recovered, he's more relaxed and he's a better wrestler," said Williams, who also coaches the U.S. Amateur Wrestling Team. "They're seeing the same Greg Gibson, but a different performance."

The Marine team includes Lou Dorrance (114 1/2 pounds), a seven-time national champion and current Greco-Roman and Sombo champion, and Craig Pittman, 1985 National Sports Festival champion (unlimited). Pittman, Gibson and Dorrance are members of the U.S. team.

The Navy team includes Dave Butler (163 pounds), the 1985 Greco-Roman champion who was an alternate on the 1984 Olympic team; Mike Carolin (198), a member of the U.S. team who won a silver medal last year at the National Sports Festival, and T.J. Jones (105 1/2), the U.S. Greco-Roman champion and an Olympic alternate in 1984.

Petty Officer 2nd Class Rob Hermann, who coaches the Navy team, will compete in the 125 1/2-pound class. Hermann was a 1984 Olympic team alternate and member of the 1985 World all-star team and World Cup team.

The Air Force team is coached by Ron Pineda, a former Marine who was instrumental in reviving the wrestling program there during the mid-1970s, when the Army dominated the competition.

The Army team is led by Brad Anderson (180 1/2), another U.S. team member who placed second last year in the national Greco-Roman championships. The team is coached by Sgt. Floyd Winters, a former U.S. team coach who directed the 1985 World Cup team and assisted the 1984 Olympic team.