Athletics: Allyson Felix leads US Charge

Three-times 200 metres winner Allyson Felix is among eight defending champions named in a powerful 129-member US world championships team.

The versatile Felix will attempt to become the first woman to win gold medals at both 200 and 400 metres in a world championship during the competition in Daegu, South Korea which begins on 27 August.

She also hopes to run in both the 4x100 and 4x400 metres relays, where she won gold in 2007.

One of her chief rivals in the 400 will be defending world champion Sanya Richards-Ross, who on Saturday ran this year's second fastest time.

Olympic and world men's 400 metres champion LaShawn Merritt, who recently completed a 21-month doping suspension, also returns to an impressive looking American field.