Kathrine Switzer, 70, the first woman to officially compete in the Boston Marathon, will be among an estimated 13,700 racing on Monday.
Using data-visualization technology, organizers can monitor everything from the density of runners at any given mile to the status of medical tents.
Seven runners ran 211 laps indoors to complete an indoor marathon in New York City.
The field includes running icon Meb Keflezighi and defending champions Mary Keitany and Kurt Fearnley.
Alicia Keys, Ethan Hawke and Katrina Bowden are among the stars scheduled to run the 26.2-mile route Sunday.
More than 50,000 people are expected to run Sunday in the city's so-called "biggest block party."
Harriette Thompson recently became the oldest woman ever to complete 26.2 miles officially.
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