NZ’s oldest last person standing format event, where participants run one 6.7km lap an hour (starting on the hour) until the last person is standing.

A Backyard Ultra is a type of ultramarathon where participants run laps of a set course of 6.706 metres (4.167 miles) and they must finish each loop in less than an hour. The race restarts each hour with all those that finished the previous lap on time.  The race is over when only one runner remains to complete a lap. This runner is marked as the winner and only finisher, with all other runners receiving a DNF (Did Not Finish). The strange distance is because the distance for 24 laps is equal to 100 miles.