LONDON, England — Melaine Walker will start her quest to retain the women's 400m hurdles title today on the third day of track and field action at the XXX Olympiad at Olympic Stadium in Stratford, London.

Walker shot to global prominence four years ago when she won the gold medal in an Olympic Record 52.64 seconds in a flawless performance and followed it up with a win the next year at the IAAF World Championships in Berlin, Germany.

The former St Jago High athlete will come into the event ranked only 11th in the world with a season-best 54.44 seconds done two weeks ago at an IAAF Diamond League meet in Monaco, one place behind MVP teammate and training partner Kaliese Spencer, who has finished just outside the medals in two global championships.

Nickesa Wilson, a fourth place finisher at the IAAF World Championships in Osaka, Japan in 2007 is the other Jamaican entrant and will run in the fourth of five first round heats ahead of Walker, who will run in the final heat, while Spence runs in the second heat.