Karsten Warholm has smashed the European 400m hurdles record again, recording the second-fastest time ever as Thomas Barr finished sixth in the Diamond League Final at the Weltklasse Zurich meeting.

Usain Bolt will head to Berlin for the World Championships as a double world record holder and triple Olympic gold medal winner – but not as defending champion.

World 100 metres record holder Asafa Powell will delay the start to his season until the end of June because of injury.