(Reuters) - Belgian ultrarunners Merijn Geerts, Ivo Steyaert and Frank Gielen set a Backyard Ultra ultramarathon world record in the early hours of Thursday by running nearly 738km in four days and 14 hours in Retie, Belgium.
The Backyard Ultra takes place on a looped track of around 6.7km or 4.2 miles. Participants must complete one loop every hour, running about 100 miles each day. The race continues till only one runner is left standing.
The bi-annual world championship allows national teams to field 15 runners each, and the country with most combined completed loops wins the competition. Races began around the world on Saturday, with 63 countries competing.
Belgium, aided by Geerts, Steyaert and Gielen's contribution of 110 laps each, won with 1,147 loops, beating Australia and United States who completed 971 and 969 loops.
The Belgian trio broke the previous record of 108 laps set by American Harvey Lewis last year and linked their arms as they completed the 110th loop to end the race together.
(Reporting by Chiranjit Ojha in Bengaluru, editing by Ed Osmond)
