A running coach I trained with years ago had a wonderful reality check for anyone considering running a marathon.

Part one required prospective marathoners to drive exactly 42.1 kilometres from their houses, park safely, get out of the car and start walking—not running—home.

Part two required paying attention to the first moment when the thought occurred: "This is crazy. What am I doing out here?"

Part three required being truthful about how it felt knowing such a thought would probably first occur with, oh, about another 41.1 kilometres still to go.

Despite the incredible growth in the popularity of marathon running over the past 15 years—major races routinely attract 35,000-plus entrants—the vast majority of people use such a test to quite sensibly stop at the "this is crazy" part and do something else with their lives. Facing down the reality of running that far for so long is generally sufficient for sanity to overcome fantasy.

Even so, only those who have run a marathon can truly grasp how much it goes beyond mere physical stamina and into the "there be dragons" realm of being mentally pulverized. Lance Armstrong, who for all his cheating still had an almost superhuman fitness level, described running the New York Marathon as the most demanding thing he'd ever done. A woman in our running group at the Paris marathon a few years ago said: "I've run marathons, and I've given birth. I'd rather give birth. At least you have a baby in your arms when you're finished."

Of course, for the Kenyans—a noun that comprises elite marathoners whether they're from Africa or Alberta—there's the prospect of actual cash across the finish line. For mere mortal marathoners—meaning anyone who runs 42.1 kilometers in more than two hours and thirty minutes—there's only the finishing time. Oh, and the race day T-shirt that you can't wear the day after the race anyway because if you do it looks like you're showing off. Oh, yeah, and the exhausted, ragged, pain-wracked, euphoric internal voice that starts saying 10 agonizing strides from the finish line: "I did it. I did it. I made it."

It is this agony of unadorned achievement that was so brutally violated by Monday's bombings at the Boston Marathon. It is, obviously, inhumane to triage tragedies that take human life. As human beings, those killed or injured in front of thousands of spectators and runners in Copley Square deserve as much sympathy, though no more, than the victims of 7-11 holdups at midnight in bad neighbourhoods. That said, the uniqueness of the vulnerability of their victimization makes the bombing feel especially abominable.

My wife said as we were watching the news coverage Monday night: "They were in the wrong place at the wrong time." To which I answered: "No, actually they were in exactly the place where they spent a year training to be, and at a time measured by both a gigantic clock and the pace watches on their wrists." In other words, they were not only where they wanted to be. They were where they had willed themselves to be. Attacking them, ambushing them, amputating and eviscerating them at such a moment somehow goes beyond the bounds of the cowardly outrages to which we are all increasingly inured.

Is what happened in Boston worse than an elementary school shooting? Objectively: no. Is it worse than a theatre or nightclub shooting of the flying of planes into buildings? Objectively: no, no and no. At the same time, it does seem a very different threshold was crossed mere metres from the finish line of the Boston Marathon. Or is that my response only as a member of the running tribe?

I had just returned from a run myself on a gorgeous Montreal April day, up Mount Royal to the Cross at the top and back, when I heard the news as I came into the change room of the Montreal Amateur Athletic building. My first concern was for the 30-plus members of the MAA running club who were at Boston. Reassured they were safe, my subsequent emotion was a bright flash of blackest revenge fantasy that involved inflicting horrible pain on those ultimately found responsible.

That, too, required a quick reality check. Vengeance will not beget justice no matter how odious the crime. So, where did that leave me? Where does that leave us as a people? Here is an image of what I am concerned might emerge from the struggle for an answer.

A few years ago, I ran a marathon in Philadelphia on a bitterly cold November day. It was snowing for the last kilometre or so. I pushed myself to my limit. When I finally crossed the finish line, I could not feel anything from my hips to the soles of my feet. My lower body wasn't just wrung out. It was numb to the point of non-existence. I felt like a torso hovering in the air. Disembodied. Amputated. Until I managed to get myself to the medical tent and pour some steaming, salt-filled chicken soup down my gullet, I experienced irrational though genuine alarm that I might have done myself permanent damage and would never recover full feeling again.

It took months to get back to real training after that, and even when I did each session was pregnant with awareness of the essential craziness of what I was doing out there. I believe the technical term is fear of being able to go on.

Societies, no less than marathon runners, are susceptible to that fear. It is imperative that we check it from ever becoming our new reality.