Gold medals up for grabs on Day 4

GOLD MEDALS UP FOR GRABS ON DAY 4:

* 15 gold medals in 9 sports

* Equestrian

- eventing team and individual - Aussies Shane Rose, Chris Burton, Sam Griffiths and Stuart Tinney in a strong position

* Swimming

- men's 200m butterfly - all eyes will be on Michael Phelps

- women's 200m freestyle - Katie Ledecky of the US is the one to watch

- women's 200m individual medley

- men's 4x200m freestyle relay - Aussies are strong bets to swim in this final with heats earlier in the day

* Other sports are canoe slalom, diving, fencing, gymnastics, judo, shooting and weightlifting.