South Africa’s Stephen Mokoka, who had never run a 50km race before, has broken the world record at the Nedbank Runified Breaking Barriers Ultra Marathon in Gqeberha on Sunday. Mokoka, 37, crossed the finish line in two hours, 40 minutes and 13 seconds, beating the record set by Ethiopian Ketema Bekele Negasa (2:42:07) at the same event last year. “I’m tired,” Mokoka, a three-time Olympian, said. “It’s a long way and I don’t know how I’m going to feel later, but I enjoyed it.” Ethiopia’s Amelework Fikadu Bosho dominated the women’s race to finish in a time of 3:04:58, nearly four minutes ahead…