John Akii-Bua, if that truly was he on the telephone from Kampala to the Reuter news agency in Nairobi, reported yesterday he not only isn't under arrest, not only isn't undergoing torture, but is getting into serious training to regain his world supremacy in track's hurdling specialty.

First, a woman identifying herself as Mrs. Akii-Bua told the curious in Kenya on the line from Uganda that the reports her husband was in the hands of Idi Amin's security forces were "complete rubbish." He'd spent the night at home and gone to work as usual in the morning, she said. "My husband is fine and there's nothing to worry about."

That's right, said (presumably) the man who set the world record in the 400-meter hurdles at the 1972 Munich Olympics, then had to stay home because of the 1976 African boycott of Montreal while Edwin Moses of the U.S. beat his record.

Akii-Bua heads Uganda's police training school. Amin even named one of Kampala's main streets after him, and gave him a promotion, following his 1972 triumph.

And credit Akii-Bua for being prepared for whatever may come. He said he started cross-country training in December.

Bill Shoemaker won't be covering any pieces of competitive ground for five thoroughbred racing days, and there go some important mounts. Santa Anita stewards have suspended him for interference in Sunday's ninth race. The suspension runs Saturday through Thursday, taking the alltime jockey off Cathy's Reject in the $150,000 California Derby on Saturday at Golden Gate Fields; the pride of the Coast, King Pellinore, in Sunday's $250,000 Santa Anita Handicap, and Nearly On Time in Monday's $125,000 Florida Derby . . .

Seems the Federal Mediation and Conciliation Service is in the market for a new director. James Scearce has found greener pastures, joining Paul Martha as fulltime arbitrators of National Football League noninjury grievances under the new NFL collective bargaining agreement. Scearce served as a mediator between owners and players association in 1974-75; Martha, a 1964-69 Pittsburgh Steeler defensive back, has arbitrated NFL injury grievances since 1970. Between them, they take over one of Pete Rozelle's former chores . . . The baseball umpires voted approval by telephone poll of the five-year contract negotiated Tuesday; starting pay rises from $15,500 to $16,500 in 1977 and '78, to $17,500 in '79-80 and to $18,000 in 1981, plus bigger boosts for seniority . . . The Detroit Red Wings and Boston Bruins have come to a "mutual consent" that both NHL teams can bargain for the WHA Houston Aeros' Howe family as a unit - the Wings own league rights to son Marty, the Bruins to son Mark, teammates of going-on-49 Gordie, who scored his 900th goal this week; matricarch Colleen wants 'em all to stick together . . .

The Montreal Expos got a big lift at their Daytona Beach bivouac when word arrived that the club and the Quebec government are agreed on an Olympic Stadium lease. They hope to be in it for the home opener vs. the Phillies April 15, and club president John McHale looked forward to seating 58,000 in the stadium, compared to 28,456 in Jarry Park, which "was quaint and fun, but that kind of thing really wore itself out" . . . Now they can try to catch up with the Canadian rival Toronto Blue Jays, whose general manager Peter Bavasi reports a baseball expansion-club-record sale of season tickets, 8,000 already. You can see why both National and American leagues were eager to corral the Ontario metropolis . . . On the bad news side, the St. Louis Cardinals carted their prize offseason pitching acquisition, Larry Dierker, off the St. Petersburg field with a fractured ankle. It gave way on him as he ran in the outfield and he is an unlikely starter before May 1. A 20-game winner in 1969, Dierker has been tailed by black cats since - arm injuries, marital problems, involvement in a fatal auto accident and a .500-area log for his last few Houston years . . .

Season tickets, again: soccer's Dips report 1,531 sold for the '77 campaign in RFK, compared to 146 all told for '76 in the suburbs . . . NASL's recent public relations director, U. of Virginia grad Chip Campbell who used to be the good-word spreader for hockey's Capitals when there was so little good word to spread, now has a golf post: P.R. director for the Ladies PGA as of March 14 . . . Another familiar face at UVa, former football coach Sonny Randle, has accepted that job at Massanutten Military Academy, Woodstock, Va. He'll not only coach but be director of admissions and alumni secretary. Can he beat his alma mater, Fork Union Military With? With no pangs?

Frank (Stubby) Overmire, 5-foot-7 southpaw for the Detroit Tigers 1943-49, later with the St. Louis Browns and briefly the Yankees, died yesterday in the hospital hard by the Tiger training base in Lakeland, Fla., where he spent several 1960s springs as pitching coach. He was 57 and had suffered a stroke New Year's Eve; career record, 58-67; in one World Series start (1945) he held the Chi Cubs to six hits, four runs in six innings - but lost to Claude Passeau's one-hitter, 3-0 . . .