REUTERS: Two ultra-distance runners pushed themselves to the limit as they smashed the world record by completing more than 300 miles in loops of a 4.2-mile track in Suffolk, England.
Matt Blackburn and John Stocker have beem competing in the Suffolk Backyard Ultra event since Saturday and organisers said they broke the record on reaching 316 miles on the 76th hour.
The previous world record of 75 hours was set by Belgian dentist Karel Sabbe in October.
Participants have one hour to complete each loop of the track and must be back in time to start the next or they are knocked out.
"What these guys have achieved is pretty incredible," race director Lindley Chambers told BBC.
"I knew we had the calibre of people taking part and I personally thought we'd do 50 or 60 loops but these guys have gone beyond my expectation and have gone further than anyone else in the world competing in this format."
There were 123 starters on Saturday afternoon and the event in the English county of Suffolk will continue through the night. The race carries on until one person is left competing.
Blackburn and Stocker have only been able to sleep, eat and recover in the short interval before starting a new lap when the clock ticks over to another hour.
By Tuesday evening, the pair had been going head-to-head for 80 hours.
(Reporting by Hardik Vyas in Bengaluru; Editing by Ken Ferris)