INDIANAPOLIS (AP) _ Kristine Quance, one of the top medalist hopes for the United States in the 400-meter individual medley, was disqualified from the event today for an illegal stroke during her preliminary heat at the U.S. Olympic Trials.

Quance was the fastest qualifier in the event at 4 minutes, 42.28 seconds, but was notified of the disqualification immediately after coming out of the water. A turn judge had ruled she made an incorrect turn as she went from the backstroke to the breaststroke.

Allison Wagner was the fastest qualifier at 4:46.65, followed by Kristin Lozeau at 4:17.45.

``It was a hairline call,'' Quance's coach Mark Schubert said. ``That call would never have been made at a World Championships or Olympics. I think it's extremely unfortunate that call was made.''

Schubert appealed the ruling with three officials, but it was allowed to stand.

``I have mixed emotions because it was my best event, the one I really trained for,'' said Quance, who now hopes to qualify for the Olympics in another event.

Earlier, Jenny Thompson was the fastest qualifier in the 100-meter freestyle although she didn't match her record-setting effort of four years ago.

In 1992, Thompson set a world record of 54.48 seconds in the event during morning preliminaries and went on to win a silver medal at the Barcelona Olympics.

Thompson qualified at 55.44. Amy VanDyken was the second fastest qualifier at 56.02 swimming in a different heat. Catherine Fox, who was in the same heat as VanDyken, was the third fastest at 56.04.

Thompson vaguely remembers the crowd at the Indiana University Natatorium erupting in cheers four years ago, although she remembers marveling at her time, which remains an American record. China's Jingyi Le set the current world mark of 54.01 in 1994.

``I was beside myself,'' she said. ``I was elated.''

Before the trials started, Thompson said she feels more pressure this time as a result of winning two Olympic gold medals in 1992.

``People automatically assume I'll be on the Olympic team. I could be sick on trial day or have appendicitis or something,'' she said. ``Nothing is for sure. If I make the Olympics, I'll be less nervous than for the trials.''

Van Dyken is just the opposite. She likes the idea of only the top two finishers qualifying for the Atlanta Games.

``To make top two, that's a lot of pressure. If you can handle it here, they're assuming you can handle it at the Olympics,'' she said.

Van Dyken began swimming after a doctor told her it would help relieve asthma. She uses inhalers to ease her breathing, much like Tom Dolan, an asthmatic hoping to make the men's team.

Van Dyken is cautious about where she uses and stores her inhaler as a result of the positive drug test by Jessica Foschi. Foschi's family claims she was a victim of sabotage.

``I never take my inhalers on deck. I never let people see me take them. I'm really quiet about that,'' Van Dyken said. ``As for sabotage, I'm not really concerned about it because I don't really think swimming is a vicious sport that someone is going to be out there to get me.''

Meanwhile, Eric Wunderlich heads into tonight's final in the 100 breaststroke hoping he doesn't repeat his third-place finish in the trials four years ago, which cost him an Olympic berth.

``Two years ago when we had our world trials here, I got over my stigma of `This is the Olympic trials pool, I can't swim fast here.' I got past that,'' he said. ``There's going to be a lot of great races here.''

Wunderlich was the third fastest qualifier today at 1:02.66. Kurt Grote had the fastest time of 1:02.12, followed by Seth vanNeerden at 1:02.52. All three qualified in different heats and were not pressured by their competition.

Josh Davis, a winner of four gold medals at last year's World University Games and a two-time national champion, was the fastest qualifier in the 200 freestyle at 1:49.34. The three fastest qualifiers were all in the same heat. Ryan Berube was second in 1:49.43 and John Piersma finished third in 1:49.75.