Kiwi ultra-marathon runner Sam Harvey is taking his long-distance ambitions to another level this week, as he chases a world record in the United States.
Heading into day four of the event, Harvey is among the final dozen still in contention at Big Dog's Backyard Ultra in Tennessee, where athletes run a 6.7km loop every hour and the last man standing is declared the winner.
Runners who complete their loop under 60 minutes can use the remaining time to sleep, eat and recover but must begin their next lap when the clock strikes the next hour.
As per backyard marathon regulations, the last runner must complete one final loop on their own, otherwise they're declared DNF and the race finishes with no true winner.
Harvey has his sights set on his own record of 101 laps (677km). As of Wednesday morning (NZ time), he had hit 83 laps (555km).
The world record is 102 laps (684km) set by Australian Phil Gore earlier this year at a race in Queensland, where Harvey developed Pneumonia and was forced to withdraw in a battle of the final two.
The event is held on the farm owned by Gary Cantrell, who's credited as the inventor of the backyard running format.
