Yiannis Kouros

Yiannis Kouros is a Greek ultrarunning pioneer whose performances helped define modern fixed-time and multiday racing. The International Association of Ultrarunners credits him with breaking more than 160 world records across distances and time limits.

His landmark results include 303.506 km in 24 hours, 473.495 km in 48 hours, 1,036.800 km in six days, and 1,000 miles in 10 days, 10 hours, 30 minutes, and 36 seconds. Later athletes have surpassed his former 24-hour and 48-hour world bests, while the historical significance of those performances remains central to the sport.

Kouros also won the first Spartathlon in 1983 and returned in 1984 to run 20:25, a performance that remains foundational to the race’s history.