Playing Sarah Connor again was not something I ever saw coming. And I wasn’t sure I wanted to because I felt pretty pleased with the character arc of the first two Terminator films. You think, “It worked — why mess with it?” But 28 years had passed, and I thought that would be a very rich landscape to explore. Obviously, it couldn’t be a redo; I’m now 63 years old. And that made it very intriguing for me. But you don’t want to let the fans down. You know the first things they’re going to look at are the “Linda Hamilton arms.” It’s like, “You want ’em? So do I, girl!” There’s pressure because fans expect you to look like a very close version of what you were. But I didn’t want to play what I was then. I wanted to play a new version of that — an older, better version.

Physically, becoming Sarah Connor for this film was very different. I trained as hard but differently. It was easier 28 years ago because I had youth and hormones on my side! I’m not unrealistic, but I’m a hard, hard worker. Mackie Shilstone was my fantastic trainer. He’s a legend and crosses over into every sport. And he understands the body in motion. Peyton Manning has even trained with Shilstone to prepare for the Super Bowl. I got to work with him because Serena Williams was pregnant. It was a wonderful accident of timing. Yes, we lifted and pumped weight and cross-trained; there were Pilates, supplements, and a diet. I didn’t eat carbohydrates for a year and a half. But everything Shilstone did with me was in motion.

Weights? Always with motion. It’s that kind of science. On the film we worked a lot of six-day weeks; even if we had a weekend off, there was probably a scuba lesson or military training. When I did have a day off, I’d sleep 20 hours. I’d rest my body and read my books to take my mind elsewhere. Still, the results are different, you know? It’s disappointing that you can work as hard and not look the same. But then you just think, “I cannot be what I was.” It took me a while to just go, “Hmm, fuck that! Let’s go with what we’ve got and make it as fantastic as possible.” I’d never felt like a badass until I made this film.

Linda Hamilton can be seen Terminator: Dark Fate, out Oct. 23.

For more stories like this, pick up the November issue of InStyle, available on newsstands, on Amazon, and for digital download Oct. 18.