The 41-year-old Kastor won last year's event in 1:13:25, and was victorious at the Rock 'n' Roll Dallas Half two weeks ago.
The 17-year-old high school senior turned professional last year and is now coached by Alberto Salazar.
Runner turnout in the Big Apple continues to rise.
40-year-old American recently finished third in the L.A. Marathon.
She advocates taking time to stretch.
Former champion has award named after her.
She was scheduled to run the NYC Half later this month.