US
Olympic champion swims second fastest 400m freestyle this year at Australian trials
Artistic swimmer Anita Alvarez pulled out unconscious by coach
Crowd favourite O'Sullivan, bidding for a sixth world title, finds himself 6-3 down to Scotland's Stephen Maguire
O'Sullivan has not reached the final in Sheffield since 2014, and is still seeking the elusive sixth crown
Usain Bolt, Ashton Eaton, Dafne Schippers, Mo Farah and Aries Merritt make the list
The Great Britain's runner stumbled at the final bend but quickly recovered to finish second in the heat