Naomi Pendergast trained the Thor actress for her return to the franchise. Here's how she got Natalie Portman into superhero shape.

On July 8th, Natalie Portman will make her return to the Marvel Cinematic Universe as Jane Foster, last seen in person during Thor: The Dark World. However, she will not be as fans last saw her, as numerous people have already commented online concerning her more muscular arms. Her fitness trainer Naomi Pendergast has revealed to Variety how that came to be.

“The goal and initial brief for working with Natalie was to develop arm and abdominal definition. However, to safely get Natalie to this goal without injury, we worked to condition her body first for about four months. This meant we could safely up the load to bulk her up without negatively affecting her joints.”

Portman and Pendergast began the workout five months before filming, continuing to train throughout the filming process to maintain the muscle. They worked for around 1.5 to 2 hours daily, depending on Portman’s schedule. Once filming started, they would train around 4:30 am since Portman’s schedule became so busy. The total time they trained for the movie was about 10 months.

Since their sessions began in the middle of the lockdown, the training initially took place at Portman’s house. Since that was the case, they mainly used free weights during that time. However, once filming started, they were able to work out in a gym, which meant that they now had access to a lot more equipment for their sessions.

“Natalie’s role was very physical and required her to do quite a bit with her upper body. Overall, she managed to get through everything really well without any major injuries. There were a few days after long stunt sessions where she pulled up a little sore in the wrists and neck, but she was able to overcome this with some release work from massage.”

Portman’s warmup routine would usually consist of various body-weight, Swiss ball, or band exercises. While stretches are sometimes included in the warmup, Pendergast usually uses exercises that activate weak muscles rather than just stretching the tight muscles. According to the trainer, that way, warming up could ensure everything is switching on before they put heavy loads on Portman’s body.

On the days they lifted weights, Portman and Pendergast would focus on the reps’ quality and the gradual load increase. On other days they would mix it up to keep it fun and interesting. A typical strength session for her upper body would include a good warmup using body-weight exercise, bands, and gliding discs. Then the main exercise set, which included supersets with about a one-minute stretch rest between each set.

“Natalie is an extremely healthy person with a very wholesome and clean diet, so we did not have to make any major changes to her food. Natalie is a vegan, so for her to get enough protein to bulk up the way she needed we had to increase her daily amount by adding vegan-based protein powders a couple of times a day.”

“Initially, it was about prepping Natalie’s body for the heavy weights to avoid injury. We worked on building her upper body three times a week, which included arm, back, chest exercises, boxing, skipping, and running. The other two days were dedicated to injury prevention work, which included Pilates-based exercises, stretching, release work, and balance exercises.”

• Dumbbell row — 10 slow reps

• Body-weight offset pushup — 10 slow reps

• Lat stretch (rest exercise)

• Dumbbell reverse fly — 10 slow reps

• Dumbbell seated shoulder press — 10 slow reps

• Back stretch (rest exercise)

• Standing dumbbell arm raise (palms up) — 20 slow reps

• Assisted pull-ups — 6-8 controlled reps

• Roll up (rest exercise)

• Dumbbell bicep curl — 10-12 reps

• Dumbbell triceps press — 15 reps

• Upper body rotation stretch (rest exercise)

Boxing and skipping round – 4-5 sets of:

• Abdominal plank on elbows — 1 minute

• Side plank on elbow — 1 minute on each side

• Basic curl focused on pelvic control

• Foot, leg, and hip stretches