Michael Johnson finished his business in the 400 metres, scarcely having broken sweat, and turned his attentions back to what has been the real show of the US Olympic trials, his sulphurous spat with Maurice Greene.

The funny thing is that people are so artful about prompting Johnson in this matter. Instead of standing up at a press conference and asking Johnson to say something mean about Greene, journalists effect concern and say things like: "Michael, you are probably aware that there has been criticism from other athletes this week about things you have said. Are you surprised and do you have any response?"

But Johnson just leans into the mike anyway and starts taking pot shots at Greene. He's just run 43.68 seconds to qualify for Sydney in the 400 metres, but he has this fly he wants to swat. "Perhaps when he's a little older he'll understand that mature athletes take criticism . . .

"He'll be in here after I beat him next weekend saying that Sydney is the place he really wants to beat me. He's been trained to say that . . .

"Look I can take criticism from somebody without making fun of their hairstyle (Michael has a complex new do, which he discloses he got done in a local salon in Dallas. "Looks cute," interjects second-placed Antonio Pettigrew)."

After 10 years of studied greyness, Johnson has emerged as a different character this week. The man who methodically irons and folds all his running gear the night before he races has been out during the day committing the verbal equivalent of drive-by shootings. Superman, as sections of the American media call the Olympic 200 and 400 champion, has been doing a little of the Clark Kent stuff by day, commenting on the trials and his rivals in a column for USA Today.

Johnson's sudden emergence late in career as a one-man multi-media entertainment centre has perplexed even his coach Clyde Hart.

Hart lives in Waco, Texas, and is by his own admission "old school".

"One things that's changed since 1996," he says about his protege as he stands outside the press tent, "he's more outspoken. I didn't know when that started, maybe about the time he got married. Maybe when he comes down here it's the only time he can speak his mind any more! Me, I don't like it. Have a lot of friends at the track. That's the way it's always been for me. I come here to see my friends, even if they are rivals they are my friends. Maybe this generation needs to spice it up a little to get themselves going. Michael is running just fine, so I don't see it as a problem on the track just yet anyway."

Neither does Johnson. His runs this year, especially while he was in South Africa early in the season, have suggested that he is on the verge of returning to peak form. After the 1996 Games, Johnson accepted a challenge to race Donovan Bailey over 150 metres on a curved track in the Astrodome in Toronto. With the boasting and the chest bumping at all-time high levels, Johnson pulled out injured after 50 yards of the race. Bailey was quick to accuse him of being chicken and those close to Johnson insist that the poultry slur took a long time to pass through the runner's system.

"He got over that physically before he got over it mentally," says Hart. "He responded better to the injury than he did to the things that surrounded it. It's all part of the mix, though."

"This season," says Johnson, "I have been running more consistently than any other year. I haven't been touching the records, it's too early for that, but I have been keeping my times on a flat line."

And as for next weekend's showdown with Greene over 200 metres, well, hand Johnson his cape. "The way I've been looking at it, I had a track meet this weekend, I have a track meet next weekend. There are seven other people in each race that I have to beat. I don't care about Maurice Greene. I'm not going to try to win this race for anyone. I'm going to win it because I can, because I'm supposed to and because I don't expect anything else."

Elsewhere in Sacramento there were changes of the guard in several events. Marion Jones' training partner, Latasha Colander-Richardson won the women's 400 metres final, running a personal best of 49.87 seconds to cause a small upset.

The men's 1,500 went to Stanford's Gabe Jennings in a race where the battle for placings was more compelling than anything else. In the end Jason Pyrah and local kid Mike Stember finished second and third, but Stember has yet to achieve the Olympic qualifying standard and must run 3:36.80 by September 11th if he is to make the team.

And in the pole vault, after the shock elimination of the heavily hyped Jeff Hartwig at the weekend, Lawrence Johnson, who smashed his right leg up in a motor cycle accident early this summer, emerged to secure the problem of stowing his pole in the overhead luggage compartment on the flight to Sydney.

The trials take two days rest starting today before resuming on Thursday and building to a weekend of blood, sweat and tears.