The night before she was to take her place as the only celebrity in a 10K race, Ashley Greene had a small confession to make: “I’m not much of a runner,” she said, laughing. “You know, I love doing different workouts, so I was totally down to do this, but this is not something that comes easy to me.”

Thankfully, if there was ever a time to lace up, it would be now. The Oakley New York Mini 10K is the world’s original women-only road race, intended to empower women (and girls!) of all ages to be active. “It’s such a good message and a really good cause,” Ashley explained. “And it’s really great to try something new.”

In fact, the Twilight star is no stranger to the world of fitness. She attributes her lean, athletic frame to “hopping around” between workouts in Los Angeles, including the Tracy Anderson Method, kickboxing, and more. “I get bored really easily, so I need to mix it up,” she explained. “In high school, I did everything: competitive martial arts, swim and dive, and competitive cheer and dance. Those are all tough sports! So from a young age, I was active.”

But that didn’t necessarily mean she was 10K-ready. “I’ve been working with a trainer, Jason Walsh. He’s very in tune with movement and making sure the body is moving correctly. I basically had to re-program my body so I was engaging the proper muscles,” she said. “I didn’t realize it before I started, but my quads were really tight! It was because I wasn’t really paying attention to my body. So we’ve reversed that, for sure.”

And true to her spirit, she’s not following the traditional route of running multiple miles. “I got myself in shape doing different things, but the great part is, no day is the same. One day will be strength training, the next I’ll be running on a 30% incline, but it’s always something new and exciting. It pushes me!” she said. “The most I’ve ever run in a day is probably three miles—doing the six or eight mile thing can take a serious toll on your body.”

Not to mention, as any exercise fanatic knows, it also does a number on your skin. “I sweat a lot,” she admitted. “But I wash my face morning and night and I always keep facial towelettes in my car so I can touch up during the day. Honestly, though, your body detoxes with sweat. So if you continue to eat not-so-great foods and drink sugary drinks, that will all come out when you exercise, but it might cause you to break out. I’ve had to adjust my diet to be as clean as possible with lots of fish, chicken, and vegetables.”

There is one thing sweat won’t get through, however. “I don’t wear makeup to the gym because I would just feel weird,” she said. “But I’m still a girl! So I wear L’Oréal Paris Voluminous Mascara. I’ve been using it for years.”

And while we’re on the topic of girly things, she also packed two pairs of sneakers just in case. “I’m thinking the grey and yellow ones,” she said. It looks like they served her well! Check her out at the race below.