Fourth for Heffernan in 50km walk

Robert Heffernan has finished fourth in the 50km walk at the Olympics, knocking almost eight minutes of the previous national record.

Heffernan crossed the line in a time of 3:37.54, with Russia's Sergey Kirdyapkin winning the gold medal.

Meanwhile, Arthur Lanigan O'Keefe sits joint 30th in the standings after the first event in the Modern Pentathlon.

The 20 year old Kilkenny man won 14 but lost 21 of this morning's Fencing matches, meaning he has it all to do if he's to challenge for honours.

Lanigan O'Keefe will now focus on the swimming segment, that gets underway just after 1pm.