(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.
