Jim Howard of Houston improved his own U.S. indoor mark in the high jump by one-half inch yesterday, leaping 7 feet 8 1/2 inches to win the event at the 45th annual Bud Light Knights of Columbus Track Meet in Richfield, Ohio.

Howard had registered the previous best indoor leap for an American three weeks ago, when he jumped 7-8 at the Millrose Games in New York. He was nearly eliminated from yesterday's meet, missing two tries at 7-7 before clearing that height.

He then made 7-8 1/2, leaving the bar up but wobbling when he brushed it with the back of his leg. The world indoor best in the high jump was set last year by Carlo Thranhardt of West Germany at 7-9 1/4.

In the pole vault, Dave Volz set a meet record with a vault of 18-8 1/2, bettering the mark of 18-4 3/4 set last year by Earl Bell.

Charmaine Crooks raced to a meet record in the women's 400-meter run and Olympic silver medalist Albert Lawrence edged local favorite Thomas Jefferson in the 55-meter dash.

Crooks won the 400 meters in 54.19 seconds, breaking the previous meet record of 54.53 set two years ago by Delisa Walton of Tennessee. Lawrence won the 55 meters in 6.13 seconds, three-hundredths of a second off the meet record set by Walton's husband, Stanley Floyd, in 1982.

Jefferson, a Clevelander who attends nearby Kent State University, finished second in 6.15 seconds.

Sydney Maree won the men's mile in 3 minutes 59.21 seconds . . .

Marita Koch of East Germany set a world indoor best of 10.25 seconds in the women's 100-yard dash at the East German Track and Field Championships at Senftenberg, the official news agency ADN reported. The previous best was 10:29 seconds, by East German Marlies Gohr . . .

In Auckland, New Zealand, John Walker became the first athlete to run 100 sub-four-minute miles when he was timed in 3:54.57, achieving the milestone in front of an enthusiastic home crowd.

Walker, 33, is the first man to break the 3:50 barrier in the mile and is the 1976 Olympic 1,500-meter champion.

Since Dec. 15, Walker has run 12 sub-four-minute miles to reach 100 -- a chase he began with a 3:58.8 clocking at Victoria, B.C., July 7, 1973. Steve Scott of the United States is next with 96 such races . . .

Zola Budd, South African-born track star who has been competing for Britain, flew to her homeland to see her sick mother, knowing that an anti-apartheid demonstration had not robbed her of a chance to compete in next month's World Cross Country Championships.

Although Budd failed to win the English cross-country title Saturday when protesters forced her to run off the course, British track selectors included her on the team for the world championships at Lisbon, Portugal. Describing the incident as "disappointing and frightening," Budd, 18, said: "My program will remain the same and this has not put me off cross-country running."

Police reported three arrests arising out of the incident at Birkenhead, in northwest England.