BOSTON (CBS) – Marblehead native Shalane Flanagan has been forced to withdraw from the 2017 Boston Marathon due to a back injury.

In a Facebook post, Flanagan said she fractured a bone in her lower back while training in the snowy weather in Portland, Oregon.

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“I’m heartbroken that I will not get the opportunity to test myself against the greatest runners on the planet,” Flanagan wrote.

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Flanagan added that she has “shed a lot of tears this past week” in reaching the decision.

A 4-time Olympian, Flanagan has run the Boston Marathon three times. She recorded the fastest time ever for an American women in the race in 2014.

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“One thing I know is that marathoners are used to suffering and overcoming challenges. We come back to try again … and again,” Flanagan said.