Summer has a strange effect on me. The long days and the bright sunshine possesses me with a terrible kind of ambition, amplifying my usual fear that I am squandering my entire life away. Sunday it was about twenty-six degrees outside by ten in the morning, and I felt like it would be a great idea to go out and run for the first time in a couple of months. As I slogged down the streets of my suburb, I learned the important lesson that parts of you can still be in shape while other, more subtle parts of you will have decayed almost to the point of uselessness.

There was a time — a glorious, magical time — when I found the energy to get up at six every other morning to go running and get exercise. Scott was gearing up to join the reserves, and he told me wild tales of how in only a few short weeks I’d be running as far as I usually drive, leaping and bounding over vehicles as though they were merely toys at my feet.

“I know it doesn’t feel like it now,” he told me confidentially, “but pretty soon you’re going to be running four or five kilometers like it’s no problem.”

“You think so?”

“Oh,” he said. “Sure.”

I got out of bed that first morning a little hesitantly. It was October, and the air was a bit chilly. I didn’t really have proper shoes, and I was wearing some shitty sweatpants and about six layers of clothing. I am a strong proponent of the theory that humans, as non-nocturnal creatures, should have absolutely no business rising before the sun does, and that therefore whatever conditions they are subjected to, however mild, are completely inhumane. Consequently, it was the coldest five degrees below zero that I have ever felt.

There’s a running track just on the other side of my block, right by the old high school where I used to go. It is generously described as a running track because it is circular, roughly four hundred meters long, and there are scattered eyewitness reports of people occasionally running near it. Its surface has the consistency of a baseball diamond that hasn’t been raked in, oh, about fifteen years, which in turn has the texture roughly equal to the surface of Mars. Rough, red, rocky and treacherous at the best of times, it was considerably more hostile on a mid-October morning.

However, it was that or run our asses around the streets of our neighborhood, huffing and puffing like we were fifty years old. We opted for the track.

I remember that we stretched for a few minutes, on Scott’s advice.

“You’re going to want to limber up,” he said. “Otherwise you’re going to hurt so bad that you won’t even want to run again in your life, let alone in a couple of days.”

I nodded in agreement, as if I had something to contribute to the conversation. We stretched.

I tugged on my feet to strech my calves. I pulled my legs up behind my other legs to stretch out my quads, I pushed my toes into the ground to tug on my octos or whatever. I was warm, I was ready, I was rearing to do.

I ran two laps.

50m: “So here’s what I’m thinking, Mike — we shouldn’t start off too hardcore. I’m thinking we should maybe go every other day to start… you know, ease our way up to around three or four kilometers within a week or so…”

100m: “…uh, I… are you okay? You’re breathing kind of heavily– you’re okay? Are you sure? Okay, so like I was saying, we should consider working up to a decent distance soon…”

200m: “…and then I said to him, I said… Holy shit, man, I’ve never heard anyone make that kind of noise before. You sound like my air conditioner before it died, and that’s fucking wrong, man…”

500m: “…um, so like I was saying, we can take it really easy in the early going, maybe we can do two or three kilometers…. maybe less…”

750m: “…we can stop if you have to… do you have to? You might have to… if you have to…”

800m: “Right. So, okay. We’ll just do a short route on Wednesday, why don’t we?”

It wasn’t that I was a total mess — I mean, I wasn’t exactly in the finest form. My legs were stiff, my breathing certainly wasn’t the best, but those weren’t the real culprits. My true Achilles Heel was actually cleverly hidden all over my freaking chest.

Specifically, there are these little thick groups of tissue along your rib cage known as the intercostal muscles, which control the expansion of your chest when you breathe. If you’re a pig or a cow, they also provide a tender, meaty meal for people who don’t mind gnawing on bones in a public forum, but that’s really neither here nor there. The important thing is that you can go entire weeks — indeed, even months or years — of your life without ever thinking about these structures, leaving them to their intercostal business, but the one time you might need them, they’ll cramp up until you can’t move any more.

Remember, even though they’re just gummy stretchy tissue between your ribs, they help to do what? That’s right — control your breathing. So it doesn’t matter how great your legs feel even though you haven’t been out for a while, does it? All the surprise in the world you might be feeling about how great your respiration is won’t count for very much, will it? Because if every tiny little muscle tucked into your chest decides to squeeze up as hard as they can, you’re going to learn that you can fall down on the ground in pain even when you’re not breathing very hard.

Such are the vagaries of physical fitness. Go right ahead and pump all the iron you want to, but don’t, you know, try to run for fifteen minutes, or some stupid isolated relatively obscure part of your anatomy will lash out at you.