“We trained for 10 months, starting around four months prior to filming,” Portman’s trainer Naomi Pendergast exclusively told Us Weekly. “Natalie did five sessions a week and did not miss one session for the whole time period we trained.”
The actress, 41, returned to the Marvel Cinematic Universe for the fourth Thor film after learning that her scientist character (who broke up with Chris Hemsworth‘s titular hero offscreen before Thor: Ragnarok) had an impressive story that includes her turn as superhero after she gets ahold of Mjölnir, Thor’s magic hammer. When Jane transforms into The Mighty Thor, she gets long blonde hair and buff arms along with some superpowers. While the CGI team could handle the flying and super strength, Portman was responsible for Jane’s buff body.
“I was asked to get as big as possible. That’s an amazing challenge — and also state of mind as a woman,” the Academy Award winner told Variety last month.
“The initial goal was to build arm and abdominal definition,” Pendergast explained to Us. “We also worked on stability and agility for injury prevention as Natalie had some dynamic stunt scenes that required her to move, twist and land in various positions. … I was also really pleased she got through the challenging stunt process without any injuries.”
Portman — who shares son Aleph, 11, and daughter Amailia, 5, with husband Benjamin Millepied — never tried to lose weight during the process, but she still had to pay attention to calorie intake. The Angel City Football Club cofounder is vegan, so she had to find ways to get extra protein to build and maintain her muscle as well as sustain her through 90 minutes to 2 hours of working out every day.
“Natalie‘s typical diet during filming would be a vegan-based breakfast of oats and berries plus a protein shake. Her snacks throughout the day would consist of fruit, nuts and salads,” Pendergast recalled. “For lunch she would have a vegan falafel dish again with a protein shake, and for dinner, a vegan curry and protein shake. This amount of food was obviously way more than Natalie normally eats, but it was essential for her to maintain this throughout filming to keep the muscle she had developed.”
The Australian trainer told Us she’s thrilled that the Black Swan star — who Pendergast described as having a “a lovely, calm and down-to earth-persona” — managed to achieve her fitness goals.
The RPX Fitness director added that Portman’s determination was essential to her training results. “I provided the exercises and guidance, but she did the rest,” Pendergast emphasized. “She is focused, determined, and humble. Natalie turned up every session that was scheduled for the 10 months and gave 100 percent, even on the days she was tired.”
She hopes to bring the same results to people working out on her app. Check out RPX Fitness’ website “for a special offer for one month free to my gym and fitness app,” the exercise expert said. “It is aimed at teaching people how to train safely and effectively in the gym, so they get the most out of their fitness training and reach their goals safely.”
Scroll down for an example of Portman’s workout routine with Pendergast: