In the video, Mary Keitany’s feet rhythmically patter on a lifeless stretch of Kaptuli Road on the outskirts of Iten, Kenya, nearly 8,000 feet above sea level. She carries her 5-foot-2, 93-pound frame with an effortless cadence alongside her three male training partners during their 20-mile run. The New York City Marathon is five weeks away.

Her alarm buzzed at 4 a.m. this day. Dedication has shaped Keitany, a 37-year-old mother and businesswoman who has won four times in New York and is the defending champion. She is the favorite on Sunday in a field that includes Des Linden of the United States, a two-time Olympian and the 2018 Boston Marathon champion, and Worknesh Degefa of Ethiopia, who won in Boston this year.

“Most ladies fear her because they know she’s faster,” said Charles Koech, Keitany’s husband, training partner and coach. Koech and their two children, Jared, 11, and Samantha, 6, travel with Keitany to most of her races.

Keitany is one of Kenya’s most accomplished runners, with seven major marathon victories, including three in London and the four in New York. Her career best is 2 hours 17 minutes 1 second, at the 2017 London Marathon, the third fastest marathon by a woman. Her winning time of 2:22:48 last year in New York was three minutes faster than her competition and the second best women’s time in the race’s history. She is the only woman other than Grete Waitz to have won New York four times or more.