NEW YORK (AFP) - Sha'Carri Richardson, the US sprint star banned from the Tokyo Olympics after testing positive for marijuana, returns to competition on Saturday (Aug 21) vowing to show the world she's back for good.

Richardson will race against Olympic champion Elaine Thompson-Herah and her Jamaican compatriots who completed a podium sweep at Tokyo in Saturday's Prefontaine Classic, a Diamond League meet in Eugene, Oregon.