This is the most empowering workout Emma Stone has ever done

Emma Stone did some hardcore training (think: deadlifts) to prepare for La La Land, so she’s no stranger to a gym. But to play the tennis trailblazer Billie Jean King, the Oscar winner had to put even more muscle onto her lithe frame.

“I had never played an athlete before and I had never been athletic before,” Stone said on Sunday at a press conference for Battle of the Sexes. The new movie depicts the real-life tennis showdown between King and Bobby Riggs in 1973.

Though she had a body double for the tennis sequences, Stone bulked up so she could bear—and feel—a physical resemblance to King. According to People.com, the actress worked with trainer Jason Walsh, who put her through a five-day-a-week, full-body weigh- training program that included 300-pound hip thrusts and 185-pound deadlifts.

“The beginning of the process was pretty brutal, but then you get into a place that’s so amazing.”

“The beginning of the process was pretty brutal, but then you get into a place that’s so amazing,” Stone said. “You start to understand the mind of someone who is strong enough to execute whatever it is they want to execute. I want to put the ball over there? I can do it. I have the strength. I want to lift this up? I can do it.”

Stone described how easy it became to lift her dogs’ 60-pound bags of food once she got stronger. “I was like, ‘I got it!'” she said, miming the casual way in which she would lift the heavy bag.

More seriously, the workouts—after which she gained 15 pounds of lean muscle—got Stone to see how King’s body and mind were connected.

“If you have the strength to be the best in tennis, you can change the world,” she said. “That was an amazing place to get to—to understand that physical strength equals strength out in our country, or in the conversation, or to further equality. I did start to put those pieces together and it was super empowering. It felt so good.”

Curious about lifting heavy weights? Here’s a primer for newbies. If you already know about the benefits of strength training, you can use this cheat sheet to sculpt your body wherever you are.