Katherine McNamara in Workout Gear Enjoys "Morning Run"

Katherine McNamara is going for a run. In a new social media post the Shadowhunter and Air Force One Down star shows off her fit figure in exercise clothes. “Y’all know that two of my favorite things in this world are going for a morning run outside and @BigSlickKC!” she writes in the Instagram caption. How does the 28-year-ol approach diet, fitness, and self-care? Here is everything you need to know about her lifestyle habits.

1. Discipline

Katherine had less than four weeks to transform her body from “this ballerina, lithe-limbed body to a marine—and then on top of that, be ready to do all of this fighting and stunt work this film required,” she told Women’s Health about her Air Force One Down routine. “I just dove in headfirst into all different kinds of training and really worked hard. But it paid off in the end.”

2. Exercise Before and After Filming

When the movie started filming she would wake up at 4 a.m., do an hour on the treadmill or bike for an hour, and then another hour of weight training. After a 13-hour work day she would return to the gym for another round of strength training.

4. Just Showing Up

“I think the most important thing I learned is: It's just get yourself there,” Katherine says about her secret trick to exercise. “There were days when I was tired. There were days when the last thing I wanted to do was pick up a weight...but I just had to physically get myself there—to take a deep breath and remember why I was doing it and why I was there. I think that can go for any kind of physical goal that someone has—half the battle is the mental battle.”

4. Healthy Diet

To fuel all the exercise, Katerhine stuck to a healthy diet. She ate a lot of chicken, vegetables, and scrambled eggs, and sometimes a potato, for carbs. “I just tried to stay pretty clean and get as much protein and fat as possible, to keep my body going but without having to work through anything processed,” she says.

5. HIIT

For her role as Clary Fray on Shadowhunters, Katherine trained for intense fight scenes with HIIT workouts. "In order to do the fight scenes, I needed a lot of upper body strength because I would be holding weapons all day," she told Women’s Health. "High intensity interval training turned out to be the perfect thing for me. I was able to keep up my cardio stamina and build upon that so I could do the fight scenes, which are basically just sprints." There is lots of research backing up the benefits of HIIT workouts, including body fat reduction, improved cardiovascular function, and mental health. It is also time effective.

6. Boxing

She also worked with a boxing trainer three-to-five times a week during production. "It builds the shape of muscles I needed to look like a fighter, and it's just plain fun," she says. "I know most people hate leg day, but I kinda love it. It's what makes me feel strongest." Harvard Health maintains that boxing is a great way to build strength, improve balance, posture, hand-eye coordination, boost mood and endurance, and helps increase alertness.

slidetitle num="7"]Two-a-Days

Katherine started weight training twice a day (once in the morning and another round in the evening) prior to filming. She also ran and did spin classes. “When you're doing a day of stunts on set, it's like being a dancer,” she says. “It's over and over and over again in these 30 to 60-second spurts of super intense, maximum-effort fighting,” she said.