Johnson goes out in style

Johnson will make his last appearance in Australia

Michael Johnson will retire from competitive athletics at the end of September.

The five-time Olympic gold medallist said he wanted to bow out while he was still at his peak.

"When I started my career, I always wanted to finish on top, like I started," said the 33-year-old on NBC's "Today" show.

"I've always been afraid of becoming one of those athletes who hangs around a little too long.

"The time is right, I've been able to do everything I wanted in the sport."

Johnson's last major event will be the Goodwill Games in Brisbane next month.

He is set to anchor America's 4x400m relay team.