Kenyan Brigid Kosgei's fastest time in Sunday's Great North Run is not valid for a world record, the International Association of Athletics of Federation (IAAF) clarified on Monday.
The London Marathon champion smashed the course record in the UK clocking 1:04:28 over the course from Newcastle upon Tyne to South Shields, the fastest performance ever over the distance.
It was fastest time in the world in a half marathon, but the course is not valid for a world record according to IAAF.
"As a point-to-point course and slightly downhill, it's not valid for record purposes, but that shouldn't take away from the performance by the 25-year-old Kenyan who dominated the race from the outset," IAAF said in a statement on Monday.
As per IAAF Rule 260.21, for a performance to be eligible for ratification as a world record:
The start and finish points on the course, measured along a theoretical straight line between them, shall not be further apart than 50 percent of the race distance.
The overall decrease in elevation between start and finish shall not exceed an average of 1m per km.
The Great North Run is contested on a point-to-point course with elevation loss of 30.5m and a start/finish separation of more than 75 percent.
Running at the front from the start, Kosgei, who raced to high profile marathon victories in London in April and Chicago last October, covered the opening mile in 4:46 and forged on from there to clip more than a minute from the previous course record of 1:05:39 set by Mary Keitany in 2014.
Magdalyne Masai was a distant second in 1:07:36, with Linet Masai third in 1:07:44. Keitany was next in 1:07:58 to round off a Kenyan sweep of the first four spots.
Kosgei said she wasn't aware that she lowered the record time by 23 seconds and was using the race as part of her preparations for next month's Chicago Marathon.
"I'm happy to have lifted the title in the race but at the same time disappointed after I was told that it wasn't a world record. I had no intention of running a fast race, but my body was responding well and that's why I registered my personal best," she told Nation Sport on phone.
She is still optimistic that she will one day break the world record both in half and full marathon.
"I'm still young and going forward I will participate in races that I know will earn me a world record because I still need to lower my personal best," said Kosgei, who trains in Kapsait, Elgeyo Marakwet County.
Kosgei's coach Erick Kimaiyo said that her performance in the race showed that she is ready for big things next season.
"She ran well though her time isn't recognised as a world record time, she has a bright future and we are going to work on the world record very soon," said Kimaiyo.