Adrianne Haslet-Davis will tackle the elements and fatigue along with other runners when she takes on the Boston Marathon on Monday.
Like few others, though, she'll be going the distance on a running blade, battling hip pain and painful memories.
"It's very difficult and there are days when I just get discouraged," she said. "But then I think I'm really lucky just to be running at all."
The professional ballroom dancer lost part of her left leg in the terror attacks at the marathon in 2013. Haslet-Davis was cheering runners near the finish line as a spectator when the second of two bombs exploded.
Despite the unimaginable hardship that followed, Haslet-Davis danced again publicly just a year later: the rumba at the international TED conference in Canada.
And last year, she did the fox trot on the finish line.
Now, the woman who had never run more than a few blocks before this year will effort the 26.2 daunting miles of the Boston Marathon.
She will look to the city that helped her heal to help her finish the race.
"I'm counting on the crowd, just like everyone is, to push through," she said. "But I know that [in] Boston — that's a given. The crowd is amazing."
Haslet-Davis knows that once she conquers the course, the finish line will be an emotional encounter.
"I know I'll be crying," she said. "Hoping that I have enough hydration to cry and run at the same time."
For Haslet-Davis, running the route is a way of saying "thank you" to the doctors, surgeons and first responders — and to the city, to which she now feels eternally linked.
"I'll always be in Boston," she said. "I love it. It's in my blood. It's everything that I have dreamed a city could be."
Haslet-Davis is running to support the non-profit Limbs for Life, based in Oklahoma.