NEW YORK – 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 June 8 in Brookhaven, New York, 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.

Still, female marathon runners encountered formidable roadblocks in the 1960s. When Roberta Gibb tried to enter the Boston Marathon in 1966, she was told in a letter by the race director that women were “not physiologically capable” of running a marathon.

To become the first woman to unofficially run Boston, Gibb hid behind bushes near the start. Then she jumped into the race wearing a hoodie over her long blond hair, along with her brother’s Bermuda shorts, having trained for the marathon in cushioned nurse’s shoes because running shoes had not yet been made for women.

In 1967, Kathrine Switzer was famously confronted on the Boston course by a race official who grabbed her and tried to tear off her racing bib, only to be body-blocked by Switzer’s boyfriend.

Kuscsik first ran the Boston Marathon in 1969 as a so-called “bandit” – without a bib or an official entry. By 1970, attitudes had begun to change when Fred Lebow, a showman who organized and promoted the inaugural New York City Marathon that year, sought women to compete in the race, which was then held entirely on hilly loops of Central Park. (It now traverses all five of the city’s borough...