BANNED IN BRITAIN

Michael Johnson may be the toast of Atlanta, but he's not welcome in London--at least on the track. The versatile sprinter, who ran the fastest time ever on American soil (43.44 sec.) in winning the 400 m at the U.S. Olympic trials in Atlanta last week, has been barred from that event at London's July 12 Grand Prix meeting, the last major test before the Games. Johnson won both the 200 m and 400 m at last year's world championships, and the Olympic schedule was adjusted expressly to enable him to attempt the same double in Atlanta. But Johnson was told Britain's corps of 400-m men didn't want to face him in their final pre-Olympic outing. "Our runners," said British Athletics Federation spokesman Tony Ward, "felt it would be a bit demoralizing running against Michael at that late stage in their preparation."

Britain's leading 400-m star, Roger Black, said no British athletes had refused to compete against Johnson, but he applauded the B.A.F. decision. The American's business agent, Brad Hunt, called the B.A.F. action "nationalist suppression" and said he would protest to the International Amateur Athletics Federation. Johnson had a more sardonic reaction. After Black set a national record of 44.39 sec. at the British trials, he noted dryly, "Maybe he runs better races when he doesn't have any competition."

--Another top U.S. runner may be barred from competition altogether. Danny Harris, who won a silver medal in the 400-m hurdles at the 1984 Olympics, tested positive for cocaine at a meet last month in Brazil and faces a lifetime ban from the i.a.a.f. Harris acknowledged a brief "relapse" into cocaine use in April. He had returned to the track last year after being forced to sit out three years for the same drug problem. He recorded the year's fastest time at the Brazil meet and beat his two principal rivals for Olympic gold. After hearing the test report, however, he withdrew from the U.S. Olympic trials, saying, "I accept full responsibility for my actions."

EQUESTRIAN Tick-Tack Go

It took the lobbying of King Juan Carlos of Spain, among others, but U.S. officials have agreed to lift a long-standing ban on horses carrying a tick-borne disease so the mounts can compete in the Olympics. If the ban had remained in force, as many as a dozen medal contenders from such countries as France, Italy and, of course, Spain might have been watching the Games on stable television. The disease, piroplasmosis, is endemic in parts of Europe and Latin America, and horses from those areas have developed resistance to it. But unexposed horses, such as most of the U.S. equine population, can face pneumonia, jaundice, even death. Under the Olympic plan, horses that test positive for the disease will be housed in a quarantined barn and checked for ticks every eight hours. Infected animals will also use a separate warm-up area and will compete only in show-jumping and dressage events, which will be held in a closed arena. Some U.S. horse owners are still grumbling, however. Says Eric Straus of the American Horse Shows Association: "We may be living with the consequences of this decision when these Olympics are just a dim memory."

TABLE TENNIS China Syndrome

Few sports are so thoroughly dominated by a single nation as table tennis is by China. The world's most populous country is so strong in the world's most popular racquet sport that two of the top 12 male players on the planet couldn't make its four-man Olympic team. But it is among women that Chinese depth is truly overwhelming. Not only are eight of the world's 12 top-ranked players Chinese, but the remaining four--who play for Taipei, Hong Kong, Canada and Japan--were all born in mainland China and nurtured in the rigorous, state-sponsored Chinese system. In fact, of the 61 players entered in the Olympic women's singles tournament, 20 are products of the Chinese system, though they represent 12 different countries. And at least 11 of the 46 countries competing in either the men's or the women's tournaments employ Chinese coaches.

"Every serious player in the world," says U.S. Olympian Todd Sweeris, "has either trained in China or has sought out Chinese players to train with." Surprisingly, in spite of all this, the Chinese do not have a lock on the gold medal, at least in the men's singles. The principal challenge comes from the defending Olympic champion Jan Ove Waldner of Sweden, which has an efficient development program of its own and is the sport's second leading power. Even Waldner, though, spent a lot of time in China in his youth.

--Reported by Jon Abbey