Probably all of us have had the experience of seeing a doctor, dentist, nurse, or other medical professional and being told that something they are about to do is going to hurt. It’s such a universal experience, that I think we forget how extraordinary it is.

Think about it: someone is telling you that they are about to inflict pain, in your best interest of course, and you cooperate with them. It’s a little human interaction that takes us right back to our childhood and to the first time that a grown-up told us we might feel “a little pinch” and then jabbed a needle into our arm. Over many years, we all accumulate these jabs, and we get used to it — sort of. It’s flu shot season, and when the nurses stick me in the shoulder, I’ll try to be brave and all, but it’s almost impossible not to tense up anticipating that tiny bite of pain.

Compared with humans, animals aren’t nearly as good at cooperating when it comes to accepting pain. There’s no equivalent of “you might feel a little pinch,” no relief at knowing that the worst is over. See how your pets react when you give them an injection. They quickly conclude that — in spite of the fact that you have housed them and fed them for the past ten years — you have suddenly become a pain-dealing psychopath to be avoided at all costs.

But humans, somehow, are able to hold at bay the desire to avoid discomfort and trust someone who tells them, “this might hurt.”

It’s a stretch to compare the compassion of a doctor giving an injection to the enthusiasm of a coach giving training schedules, but I think the analogy is interesting. For one thing, coaches do — intentionally or not — hurt their athletes. Unlike doctors, who proceed with full confidence that a) most of the pain they inflict fades away quickly and b) the good they do far outweighs any temporary discomfort, the coach sees “through a glass darkly” and can’t ever be sure of the full consequences of training.

It’s a sad fact that runners get injured. It’s also a sad fact that many, if not most, injuries are associated with “training errors,” usually doing too much of what is supposed to be a good thing. As a coach not a doctor, I live with anxiety that the training I dole out has the potential to hurt, and not hurt like a small jab in the arm, but like six weeks of no running or impact. What makes it worse, of course, is that athletes trust their coaches to always have their best interests at heart. It’s one thing to say, “these 400s will hurt, but you’ll see the benefits in a few weeks when you race,” and quite another to say “all this mileage will hurt, but it will pay off handsomely in a few months, unless it leaves you injured and unable to finish your senior cross country season.”

To continue torturing the analogy, doctors are enjoined to “do no harm” and we trust that any discomfort we suffer at their hands does not harm us. I think coaches have a similar responsibility to do no harm, but it’s impossible to deny that harm gets done. Maybe coaching lacks the scientific rigor of medicine, or maybe the athletic endeavor has built into it a different scale for assessing risks and rewards. In theory, everyone can be healthy, but not everyone can be a star athlete. Whatever the reason, coaches are out there experimenting on their subjects — I mean athletes, of course — and the results are not always happy.

Probably most successful coaches internalize but do not dwell on the risks of training. Maybe this fatalism forms part of the coach-athlete relationship, where the athlete, too, understands the risk, and chooses to trust that the “medicine” of training will have a beneficial effect.

I remember one time when I was having my blood drawn that the nurse missed the vein and injected the needle into something much more sensitive, like muscle tissue. My arm hurt for quite a while after that, and it took me a while to “forget” the possibility of it happening again the next time I went in. Had the same thing happened to a dog on a visit to the vet, he’d never forget. He would never believe me that “this might hurt” meant anything other than he should hide under the bed.

But somehow athletes and coaches manage to move on and not stay under the bed. It’s remarkable, when you think about it.