Rob Muzzio and Abdi Bile, NCAA champions from George Mason, will miss the outdoor intercollegiate track season because of injuries. Muzzio is the two-time defending NCAA decathlon champion; Abdi was the 1,500 meters champion at the 1985 NCAA outdoor meet.

Muzzio, the only athlete to win NCAA decathlon titles two years in a row, suffered a slight tear of his left calf muscle while competing at the Florida Relays in Gainesville March 26.

"Naturally, I'm disappointed," said Muzzio, who will miss the opportunity to attempt a record third consecutive title. "But I have a whole year of eligibility remaining and I'm looking forward to that."

Abdi, who ran the fastest mile (3:53.08) by a U.S. collegian in 1985, has been hampered by a pulled hamstring for the past two months. A native of Somalia who competed for that country at the 1984 Olympics, reaching the semifinals of the 1,500, Abdi was undefeated against collegiate competition in 1985.

"Rob and Abdi's futures are more important than trying to rush them back into action this spring," Coach John Cook said in a press release. "They can take the time necessary to recover, then we can start getting them ready for next year." . . .

Murray Arnold, 48, an assistant coach for the Chicago Bulls of the NBA, will be the new head basketball coach at Western Kentucky, school officials announced today in Bowling Green, Ky.

"This is certainly an exciting and thrilling moment to be added to the list of great basketball coaches at this great university," Arnold said at a news conference. He is a graduate of American University in Washington and once was an assistant coach at DeMatha . . .

Tony Shaver, who coached Episcopal High School of Alexandria to a 21-2 record for the co-championship of the Interstate Athletic Conference last season, has been named basketball coach at Hampden-Sydney (Va.).

Shaver replaces interim coach, Joe Lammay, who led the Division III school to a 9-16 record last season. Shaver said, "I really like Division III, where you eliminate some of the cutthroat tactics that Division I faces at times."