Editor's note: CNN's Tom Foreman is an avid runner and ultra-marathoner.
(CNN) -- I was working at my desk in D.C., following race reports from Boston on Twitter, wondering as I do every year if I'll ever be fast enough to qualify.
The elite runners had long ago crossed the finish line and the back of the pack was ambling along when the door burst open and several colleagues rushed in. "There's been a bomb at the marathon!"
My heart sank. I knew they were telling me as a journalist, but I heard it as a runner.
For well over a century, Boston has been hallowed ground for those of us who run. Boston is where the endless miles of training -- in rain, heat and snow -- lead.
Boston is where the agony of the hills and the brutality of the stopwatch are pounded into submission by 26.2 miles of glory.
It does not matter if you finish first or last. Simply being in that legendary race is the goal. Forever dreaming of it is the reality for most of us.
And then, in 12 horrific seconds, a sporting event that has inspired, challenged and rewarded Americans for more than a century was turned into something awful, ugly and painful.
Make no mistake: Any decent runner in the land will tell you that nothing about the race even slightly matters compared to the suffering and grief of those people caught in the blasts. Some runners who had just covered nearly the whole course were among the first to rush over and offer aid. No matter how many years of effort they'd spent to reach the race, they knew there were real victims here, and the finish line didn't matter anymore.
I have covered many explosions, massacres, wars, natural disasters and horrific accidents. I know that human loss should always trump all else. But I've also learned that sometimes other things are lost, as well, and even if they don't matter as much as the human suffering, they matter just the same.
And for so many of us who take to the roads, paths and trails, the essence of running is freedom; our freedom to step outside, stretch our legs and fly along the ground wherever we choose for as long as we please. It is a celebration of human ability and excellence. It is a struggle. It is a triumph. And this was an attack on all of that.
The point of terrorism is to terrify, to drive us all away from the open roads, to force us into hiding, to make us shrink from each other and from public spaces, to make us run...away.
I worked all day covering the blasts. I collected information on the victims, the investigation and the hunt for suspects. I checked in on friends who'd been at the race. The phone rang late as I was finally wrapping up. It was my older daughter at Georgia Tech. We marathoned together a few years back, and we still join each other for races whenever we can.
"How are you," I asked.
"Not great," she said. "It's all so sad. I went for a run. You understand."
I do. And I know she was not alone.
I know as sure as I breathe that in all the depressing, bewildering hours since the attacks, that this has been the answer from runners all across our land.
They have strapped on their shoes, stepped outside and in silent tribute they have run. They have run in defiance of those who would presume upon our freedom. They have run in respect for those who died or who were hurt cheering on this silly sport we love. They have run as we've always run, to test the limits of human possibility; not to defeat others, but to improve ourselves.
They have run as I will run...for Boston.