Kamworor is undefeated this year while the 37-year-old Flanagan is again hinting at retirement as she prepares to face fast Kenyans Mary Keitany, the three-times New York winner, and reigning London champion Vivian Cheruiyot, plus fellow American Des Linden, the Boston champion.
"Some days I use retirement as motivation, like telling myself, 'You only have three more workouts you ever have to do, just give it all you have," Flanagan told Runner's World magazine.
Many thought 2017 would be her last marathon after Flanagan became the first American woman in 40 years to win in New York, but the Boston area native decided to give the distance at least one more year.
The task will not be easy. Keitany was not in full health when she finished second to Flanagan last year and Cheruiyot has beaten the American in all 11 of their races.
Both have faster career bests than Flanagan, Keitany having run 2:17:01 in 2017 and Cheruiyot an impressive 2:18:31 at London.
Flanagan's best is 2:21:14 from 2014.
READY TO REPEAT
Kamworor, 25, has won three consecutive world half marathons and the past two global cross country titles and says he is in good shape.
"I have trained well," he told Reuters television.
The 2:06:12 runner could have his work cut out, though, with young Ethiopian Shura Kitata ready to challenge.
Kitata, 22, blazed to a 2:04:49 finish in claiming second at London in April.
Countrymen Lelisa Desisa, twice a Boston winner and the 2016 New York runner-up, and Tamirat Tola, the fastest in the field with a 2:04:06 personal best, and 2017 London winner Daniel Wanjiru of Kenya are others to watch.
The race, expected to be run in ideal conditions, will also see the marathon debut of 43-year-old Bernard Lagat, the American record holder at 1,500 and 5,000 metres. (Reporting by Gene Cherry in Raleigh, North Carolina, editing by Ed Osmond)
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)