50 worldwide contenders for 2012: Jordyn Wieber
Last year was Wieber's first at senior level - but what an impact she made. She signalled her arrival by beating then-world champion Aliya Mustafina at the American Cup on her international debut.
Wieber then took the individual all-around title at the World Championships and helped the USA to team gold.
Wieber got her first taste of gymnastics as a four-year-old after her parents put her in a recreational class because they noticed she had unusually large muscles for a young child.
Did you know?
Winning Olympic gold is Wieber's main ambition - second on the list is meeting pop idol Justin Bieber.