Plus-sized model Erica Schenk says she’s been running for about 10 years, ever since she was a kid playing volleyball.

Even so, she probably didn’t think she’d one day be a poster girl for the sport; certainly she didn’t expect to be at the centre of a debate about athletics and aesthetics.

The cover that “sent an unambiguous message” about keeping fit.

But that’s where she finds herself after gracing this month’s cover of Women’s Running magazine.

Almost from the moment the issue hit newstands in the US, health experts started discussing just what a fit body is supposed to look like these days.

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Schenk’s appearance is vastly different to that of the runners usually featured on the magazine’s cover – they’re typically thin, muscled and long-legged.

Schenk is none of those, but the magazine’s editor-in-chief Jessica Sebor said people shouldn’t “judge a runner by her cover”.

“Just as someone can appear to be in shape, when in fact she’s destroying her body, someone can appear to be conventionally out of shape when she’s an athlete to be reckoned with,” said Sebor in an interview “justifying” Schenk’s selection as cover girl.

Body image expert Harriet Brown, author of Body of Truth and Brave Girl Eating, welcomed the photo of 18-year-old Schenk.

“This cover will empower and remind so many women that they don’t have to be slender with six-packs to get out and do something positive for their health and well-being,” Brown said.

“The cover sends an unambiguous message that runners come in all shapes and sizes.”

Schenk took to social media to celebrate her photograph. In interviews she was quick to defend both her shape and the shot.

“Some women believe that since they have curves they can’t run or shouldn’t run,” said Schenk. “Running is for every body anytime.”