Kathrine Switzer, the trailblazing female pioneer who made history in 1967 as the first female contestant of the Boston marathon, is running the race once again today – 50 years on from her groundbreaking victory.

The 70-year-old athlete was seen waving to the crowds as she prepared to compete in the annual event, wearing a bib labelled 261; the same number that became a source of motivation to women the world over during her first appearance on the circuit.

Today, Switzer received a hero’s welcome but she faced a very different reception half a century ago, aged 20, when major races were considered the domain of men.

In her memoir Marathon Woman, Switzer describes how most competitors at the male-only event greeted her with friendliness to begin with – even if her running companion Tom Miller did mock her for wearing lipstick.

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“Many of these guys turned right around and jogged over, all excited,” she writes. ““’Hey! You gonna go the whole way?’ ‘Gosh, it’s great to see a girl here!’ ‘Can you give me some tips to get my wife to run? She’d love it if I can just get her started.'”

Then she recalls how – midway through the race – race manager Jock Semple suddenly accosted her and tried to tear off her bib.

“A big man, a huge man, with bared teeth was set to pounce, and before I could react he grabbed my shoulder and flung me back, screaming, ‘Get the hell out of my race and give me those numbers!’” she recalls. “Then he swiped down my front, trying to rip off my bib number, just as I leapt backward from him. He missed the numbers, but I was so surprised and frightened that I slightly wet my pants and turned to run.”

She describes how “this Jock guy, had me by the shirt”, when her running mate Tom suddenly swooped in and knocked him away. 

The dramatic event actually ended up spurring Switzer on, even as she feared being arrested at the end of the race:

“If I quit, everybody would say it was a publicity stunt. If I quit, it would set women’s sports back, way back, instead of forward. If I quit, I’d never run Boston. If I quit, Jock Semple and all those like him would win. My fear and humiliation turned to anger.”

 Switzer ended up finishing the race in four hours, 20 minutes.

Her remarkable feat took place five years before the Boston marathon first allowed women to race officially in 1972.

It was a historic moment that led her to launch the 261 Fearless foundation; an organisation that draws from the inspiration of her bold achievement to support women as they “take on their personal challenges through running or walking”.

Switzer will today lead a team of runners from the nonprofit company, as she continues on her mission to empower women through running. This year she’ll be joined by an estimated 13,700 other women, in a moving symbol of social progression.

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Switzer originally ran the male-only event by signing her name “K. V. Switzer” on the application form.

Another woman, Roberta Gibb, had also completed the race a year before but she hadn’t registered for the event, so her accomplishment wasn’t officially recorded. She disguised her gender by wearing a top with a hood.

Prior to her 1967 victory, Switzer had been told “no woman can run the Boston Marathon” - before proving exactly that.

Nowadays, she continues to receive letters and photos from women all over the world, who delight in the iconic number 261. Some even have tattoos dedicated to it.

“What they were really telling me was, ‘That number makes me feel fearless,’” Switzer tells Newsweek. “Because ‘I, too, relate to a story about me being told that I’m not welcome or I’m not good enough or I can’t do it.’”

Photos: Rex Images