My legs were so sore, there was no way I was getting out of bed. I was three weeks out from the Country Music Marathon in Nashville, and I honestly wasn't sure my body was up to the task. I'd been following a training plan, sure, but most days, my muscles still felt like they were revolting against another day of self-inflicted torture. Why had I decided to do this again?

After years of viewing myself as chronically unathletic and uncoordinated, this would be my first full marathon.

Growing up, I'd tried every sport in the book, but I could never stick with any of them—partially as a result of my inevitable embarrassment when kids half my age would smoke me in tennis matches or volleyball games. I dreaded gym class... or anything involving sneakers, really.

In contrast to my lack of skill on the court or field, my father has always been able to do anything athletic he sets his mind to. He ran his first full marathon in his 40s and has since gone on to race duathlons and even some ultras (including a relay race where teams travel together in a van and take turns running throughout the night—no joke). Like many serious runners, he's always talking about how the sport has changed his life—so much so that, eventually, I decided I wanted to be a runner too.

This particular day, the carefully planned Excel sheet taped to my bathroom mirror spelled out my fate: 20 miles.

The big two-zero, the peak of my training, and supposedly proof that I could complete the race. If it weren't for scheduled runs with my dad every weekend, I doubt I would have had the willpower to run double-digit mileage—especially after a long night out during my last semester of college.

Like every other weekend, he met me at my door in knee-high compression socks and sporty sunglasses that made him look like he was prepping for the Tour de France. Though he wasn't training for a marathon at the time, I could sense how excited he was that I was working toward one of my own. "Marathons are all about mindset," he told me over and over, and I believed him. Convincing myself I could do the mileage was always half the battle.

As we set out for a greenway not far from my apartment, I was feeling more defeated than usual. This training program, the same one that had gotten dad through his first race, was slowly killing me. My legs hurt. My feet hurt. My hips hurt. But having him on this run with me meant I couldn't back out. Damn him.

EDITOR'S PICK
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My dad and I haven't always had an easy relationship.

We were close in my childhood, but as I grew older, we went through a period of strained distance that sometimes felt miles wide. There was a phase after my parents split when my dad and I didn't talk much.

As I fought to reconcile my confusion with my love for him, I responded in anger and bitter resignation. I held pain like a knot in my chest, even when I knew he wanted to help me heal. I cried out for clear answers, and that was never something anyone could give.

I needed something to restore the connection between my dad and me, something that didn't bring our suffering into full view.

Those days on the phone when I wasn't sure what I could say to him, I'd bring up for the half-marathon I was working toward at the time. If our conversation fell silent, each of us unable to express our sadness, I'd turn to what we both knew well.

"My feet are bothering me. Do you have any advice?" "What happens if I skip a couple shorter runs during the week?" He was always patient and always helpful, giving me tips about double-layered socks or the best foam roller to buy online.

I'm not sure if these conversations meant the same thing to him, but they gave me a specific purpose when we talked, a way to bridge the disconnect that had been growing in my heart for so long. I couldn't find answers about the division in our family, but I could talk with him—really talk—in a way that didn't end in tears and heartache and pain. And for us at that time, that was progress, and that was enough.

When I run, he plays both cheerleader and coach, the perfect balance between tough love and encouragement. He's taught me never to cut a long run short, even if I have to walk it. He introduced me to the perils of trail running and laughed as I tripped on a rock in front of strangers (a rite of passage, he says—every runner needs to fall on their face at least once).

He has blown me away with his ability to push through long distances, even with sore muscles or a cold that won't go away. During our morning training runs, we'd spend hours talking about history and politics, while he gently reminded me to cut out the bounce in my stride.

Yes, crossing the finish line of that marathon taught me about my own resilience. But maybe the biggest thing running has shown me is what it looks like to love someone. It's painful, it's unpredictable, and some days are easier than others. You might feel stronger than ever one morning and realize you can barely move the next. Like a lot of things worth doing, it hurts.

Becoming familiar with your pain is unavoidable as a runner.

You have to acknowledge and accept the pain while asserting that it doesn't own you. Otherwise, you miss seeing all the good things that can exist in its midst: strength, resilience, humor—even joy.

Learning to be present with pain was crucial to defining myself as a runner, and it has carried over into every aspect of my life, including my relationships. Dad and I still have things in our past that feel raw, but this is one area where I know I can always count on him.

Just like my training, our relationship is a constant work in progress. But I'm sure of one thing: Facing pain head-on teaches you how to live in its company. No matter how detailed the training plan, we can't always predict how real life is going to affect us. Sometimes things just hurt, and there isn't any way to get around that. Living with pain and joy all at once is the only real way to keep moving.

Sarah Ellis is a grad student, runner, writer, and very bad dancer. She's probably drinking kombucha and pretending chocolate is a health food (because it is, duh).

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