Backyard ultra
The backyard ultra or last one standing is a form of ultramarathon race where competitors must consecutively run the distance of 6.706 kilometres (4.167 mi) in less than one hour. The distance of each loop (aka Yard) is equal to 100 miles divided by 24 hours, or 1/24th of 100 miles, so that a competitor would run 100 miles for a full day (24 hours) of competition. They must repeat this every hour until only one person completes a full lap - the last one standing.
The backyard ultra format has gained a reputation for its grueling and unpredictable nature, as well as the camaraderie among participants. Challenges include sleep deprivation, exhaustion, and varying weather conditions.