SEATTLE, JULY 26 -- Jackie Joyner-Kersee, the Olympic heptathlon and long jump gold medalist, probably will miss the remainder of the track and field season because of an injured right leg, her husband and coach Bob Kersee said today.

Kersee said his wife had "a second-degree strain in the right quad{riceps}."

"Me being very cautious, I would assume her season is over," he said. "It might be a tear."

Kersee said the injury occurred when Joyner-Kersee was running in the 1,600-meter relay at this month's Olympic Festival in Minneapolis and continued to bother her here, where she won the Goodwill Games heptathlon. However, her score of 6,783 points was far below her world record of 7,291.

Kersee said his wife felt the strain during a workout today, then saw a therapist. "We'll go home {Friday} and get it taped," he said.

If it's a tear, Joyner-Kersee probably would rest until October before resuming training. Conway Leads U.S. Team

High jumper Hollis Conway led an American sweep, while women's hurdler Sandra Farmer-Patrick and triple jumper Kenny Harrison paced 1-2 finishes tonight.

Americans came in 1-2-3 in the women's 400 hurdles, but Janeene Vickers was disqualified for going around a hurdle, even though she already received the bronze medal.

The track and field competition ended with a flourish for the Americans, as they also won the men's 400- and 1,600-meter relays and women's 400-meter relay.

Overall, the U.S. team outdueled the Soviets, winning 20 gold medals and 52 overall. The Soviets finished with 14 golds and 46 medals.

Conway won at 7-7 3/4, then missed three times at 7-10 1/2, a height that would have broken his American record by a half-inch.

Doug Nordquist and Tony Barton each cleared 7-6 1/2, as did Sorin Matei of Romania, the 1990 world leader at 7-10 1/2. But Nordquist, who got over on his first try, received the silver medal; Barton, who cleared on his second attempt, earned the bronze, and Matei got nothing.

Farmer-Patrick, unbeaten last year and the nation's outstanding woman's track and field athlete in 1989, bolted into the lead early in the 400 hurdles and won by three meters in 55.16 seconds.

She was followed by Schowanda Williams in 55.65 and Vickers, the NCAA champion from UCLA, in 56.09. Then Vickers was disqualified.

Harrison overtook teammate Michael Conley -- just as he did at the national championships -- on his final jump, soaring 58-1 3/4. Early this month, Harrison triple-jumped 58-10, the second-best in history.

The most exciting relay was the men's 400. Anchorman Dennis Mitchell overcame a two-meter deficit, caught Cuba's Joel Isasi with five meters left and outleaned him at the tape.

The U.S. time of 38.45 was the second-fastest in the world this year, and Cuba's 38.49 was third best.

Preceding Mitchell were Mike Marsh, Daron Council and Andre Cason.

In the 1,600 relay, the U.S. team of Clarence Daniel, Andrew Valmon, Antonio Pettigrew and Tim Simon produced the fastest time this year, 2:59.54.

Evelyn Ashford, the 1984 Olympic 100-meter gold medalist, turned in a sparkling anchor leg in helping the U.S. team win the women's 400 relay in 42.46, the fastest in the U.S. and the second-best in the world this year.

Meanwhile, Igor Astapkovich uncorked the four longest hammer throws in the United States, leading a Soviet sweep of the medals. Astapkovich, 27, the 1989 and 1990 Soviet champion, won with 276 feet, second-best in the world this year. USOC Pays for Testing

It may be Ted Turner's show, but the U.S. Olympic Committee is footing the bill for all drug testing at the Goodwill Games.

The governing bodies of all sports involved in the Games insisted on drug testing.

"Turner had not planned to provide testing, but the federations went to the USOC and asked for it," said testing coordinator Jeanette Grice.

The testing will cost the USOC $200,000 for the 600 to 650 tests.