The life of an NBA referee doesn’t leave much time for working out.

Sure, they get plenty of cardio running up and down the basketball court each game—five miles of it, in fact—but to keep up with players like LeBron James, Giannis Antetokounmpo, and Kevin Durant, referees need to put in work off the court, too. But with new cities every night, long days of preparation, different timezones, hotels—it’s a grueling schedule that doesn’t leave much time to get into the gym.

“We can be up until 3 a.m., finishing the game from the night before, then be on the first flight in the morning,” 20-year veteran referee Marc Davis tells Men’s Fitness. “The days can morph into each other. Nobody really cares about how much sleep you got that night—you still need to call the game. It’s a physically demanding job, and our players are just so athletic, just incredibly talented. But you have to keep up.”

The tough schedule and limited free time is why Davis keeps a list of workouts broken down by length to make sure he always has something to do—no matter where he is, how much time he has, or what he has available—he has a way to get in a workout.

“I attack my workout based on the amount of the time that I have,” Davis says. “I keep a bunch of workouts in my phone, so whether it’s 10 minutes, 30 minutes, or an hour, I have something I can do. I focus on mobility in my training; I do a lot of bodyweight squats, and kettlebell workouts. KB’s are great because you can use it for a lot of different areas and in all kinds of routines.”

Davis works out year-round to stay in shape, and he thinks that the way he trains can be helpful to people with busy lives. Much like the way Davis deals with his grueling schedule as a referee, people also have jobs, travel, families, and other responsibilities that may limit the amount of time they have to get in a workout or go to the gym.

“Doing something daily, even a short workout, my advice is to just get moving,” Davis says. “Your body wants to move and the more it moves, the better it moves and feels. Consistency matters. Doing something five, six days a week is much better than doing a whole lot once or twice. Stay accurate every day. In our society now, there's very little physical activity that's required for many jobs, and that can create a somewhat sedentary lifestyle. If it's just an hour walk—my crew, they make fun of me—but we always walk for an hour after lunch. It's just...It's cold, so what, we need some fresh air.”

Here’s a look at how Davis gets in his workouts when he’s working during the NBA season.