Nina Kuscsik, the first woman to enter the New York City Marathon and the first official female winner of the Boston Marathon, who in the 1970s repudiated the widely-held and unfounded belief that women could not and should not run such races of 26.2 miles, died on June 8 in Brookhaven, N.Y., on Long Island. She was 86.

Her daughter, Chris Wiese, said Kuscsik was diagnosed with cognitive impairment in 2014 and had recently been treated for bouts of pneumonia. She died in a hospital.

A superb all-around athlete and a New York state champion as a cyclist, speedskater and roller skater, Kuscsik took up distance running in 1967 to keep fit when her bicycle needed repair.

She ran more than 80 marathons raising three children for part of that time as a single mother, all while working as a patient representative at Mount Sinai Medical Center in Manhattan.

But Kuscsik and other female runners first encountered fierce resistance from a male-dominated running establishment, which believed, along with many scientists and doctors, that women would risk infertility and even possibly lose their uteruses if they competed in marathons.

Kuscsik often said in response, “I proved it over and over — my uterus didn’t fall out; I’m fine,” her daughter recalled in an interview.