I'm 45 and survived an hourlong workout with NFL players. I'm proud that I was able to keep up.

At 45, I often wonder if I can still do what I was able to do in my 20s. During those glory years, I did a lot of physically challenging things: I served in the Marine Corps, I completed an Ironman triathlon, and I worked as a personal trainer.

Almost two decades later, I can appreciate that I'm now in a different era. While I've stayed in shape in the years since, time has taken its toll on my body.

Recently, a gym in Miami invited me to meet active NFL players and complete an offseason workout with them. At first, I was hesitant to join, but I wanted to prove to myself that I could still perform with the best. So, I said yes.

Learning the workout at Legacy

The workout took place at Legacy, a gym in the Little River section of Miami and run by a former college football player named Manning Sumner. He built the gym out, complete with a coworking space, a podcasting studio, and a smoothie bar selling $12 shots of kale.

I walked in with visions of NFL offseason workout videos, where guys pull farm equipment up hills with a bungee cord and run wind sprints around Lake Tahoe. The players' trainer, Isaiah Ross, aka Rozay, assured me no farm equipment would be involved and then introduced me to the players.

I was paired with Janarius "J-Rob" Robinson, a defensive end for the Kansas City Chiefs who, after football, could have a solid career as a stand-in for Bane, or, in a pinch, the Great Wall of China.

Pull day began, and I was able to kind of keep up

The pull day workout was a series of circuits, where each pair moved from station to station with minimal rest.

Our first exercise was a cable twist, where we were told to "explode" while pulling an entire stack of weights from our hip over our shoulder. Once I got the form down, I was able to keep up with J-Rob. I felt good about this until Rozay said, "Yeah, they just finished an hour of position drills outside."

The next exercise involved doing push-ups on an exercise band stretched across the bottom of a squat rack — with your feet on a Bosu ball. J-Rob said he was going to "take it easy" because he had a shoulder injury. He stopped after doing 25. With that number in mind, I put my arms on the band and was determined to at least make it to 25, which I proudly did.

You've got to use your hips

Fresh off this triumph, we began a second circuit by tossing a 50-pound medicine ball to each other, backward over our heads, from a kneeling position, roughly 30 yards apart. J-Rob casually tossed his right to me.

"You gotta use your hips," he said. Hips, and 250 pounds of NFL muscle mass, I figured.

Still, I took his advice, and to my surprise, my toss made it all the way to his feet. I impressed even myself.

Next, we were to pull a weight sled toward ourselves using a pair of straps, hoisting the straps over our head with each rep. I watched as defensive end Marcus Bragg ripped each rep about as casually as I'd open an umbrella.

"Use your hips," he said.

I listened, and using my hips, I completed every round of this sled pull. It turns out that if you use the correct form, you can accomplish a lot in the gym.

I'm proud of what I was able to do

Mercifully, after about an hour, Rozay decided we'd had enough and led us in some cool-down stretches.

That's when I realized that even though I'm getting older, I can still push my body to do something amazing. I had managed to at least keep up with NFL players for an hour, if nothing else. Once I took their advice, adjusted my form, and got into the right mindset, I realized I can still get through harder things.

I also proved to myself that even though my body isn't the same as it was in my 20s, I can still keep up. And for that, I'm proud.