Allyson Felix has dominated the 200m since taking silver at the last Olympics as an 18-year-old.
She is the owner of the fastest 200m by a woman this century and at the 2007 World Championships she won her main event as well as the 4x100m and 4x400m relays.
In doing so she became only the second female to win three golds at a worlds.
The only things missing from her collection are an Olympic gold medal and the 200m world record. Can she achieve both in Beijing?
PATH TO THE PODIUM
2008 form: She ran 21.82 to win the US Trials - only one-hundredth of a second outside her best time. She also ran a PB in the 100m in the trials in June, but still failed to qualify for the event. She came home in fifth place to end her ambitions for four golds in Beijing.
At Crystal Palace recently she trailed home in fourth place behind Jamaican rival Sherone Simpson and left the track shaking her head after a rare defeat.
Rivals: Simpson heads a trio of Jamaican contenders. Veronica Campbell-Brown beat Felix in Athens and has run 21.94 seconds this year, while Kerron Stewart has also gone under 22 seconds in 2008.
The US have sprinting strength in depth so Muna Lee, the 100m champion at their trials, and Marshevet Hooker cannot be counted out.
How she could win: From behind. She is not always the quickest out the blocks but her long stride usually carries her through in the second 100m. Worryingly for her rivals, she says she has been working hard on her "first 80m and running a tight bend".
What she says: "It all happened so fast for me. You do just sometimes look around and realize that and go: 'Wow'."
Sporting high: Felix was initially disappointed by silver in Athens, but soon realised what an achievement it was. She followed it up with 200m gold at the World Championships in 2005 as a teenager and afterwards she said: "I don't think it's really sunk in yet but I would think this is the start of something big."
She wasn't wrong. She was undefeated in the 200m that year, set PBs for the 100m and 400m and won the Jesse Owens Award as the USA's top female athlete.
Sporting low: Not a long list, but after the highs of 2005 she suffered a season of injury and illness in 2006.
In action: The first two rounds take place on 19 August, the semi-finals on 20 August and the final on 21 August.
AWAY FROM ATHLETICS
Life before sport: Despite winning an Olympic medal and becoming a world champion in her teens, Felix was a relatively latecomer to the sport. She played basketball and did not take up athletics until her first year of high school.
Felix's father is a pastor and she was brought up "in a very strong Christian home". "I came to know Jesus Christ as my personal saviour at a very young age," she says.
Hero worship: Ironically it was former US sprinter Marion Jones. The disgraced sprinter grew up nearby in California and her performances at the 2000 Olympics inspired Felix.
Felix is a volunteer for Project Believe, an intensive anti-doping programme carried by the United States Anti-Doping Agency where she puts herself forward for out-of-competition testing.
Most likely to: be found relaxing in her spa after races. She says: "Soaking in my hot tub is as vital as warming up and training before any race. This is therapy for mind, body, and soul."
Least likely to: complain about a bit of pain. Her father said she had her wisdom teeth removed with almost no medication so as not to take a chance on an accidental positive drugs test.
Did you know? She has earned the nickname "chicken legs" because of her "long, skinny legs". Despite that she can still leg press 315kg.