Maurice Greene ignored a scattering of boos on Thursday to run the fastest 100 metres in the world this year, 9.90 seconds, in the first round of the U.S. championships and then pulled out of the rest of the games in protest.
The Olympic champion and world record holder, who false-started before tying the U.S. championship record, is upset at an American rule that requires world champions to participate in the U.S. event to receive a bye for the world championships in Edmonton from August 3rd-12th.
"I slowed down a bit at the end, but I hope the fans are happy," said Greene.
He did not address his unhappiness with the new rule, as he had on Tuesday, but said: "I truthfully do need the rest".
An ice pack was resting on his left knee, but Greene would not say if he was injured.
"Rest right now would do my body very good," he said. "I need to make sure I am 100 per cent ready for the world championships."