Natalie Portman’s ‘Thor’ Workout Revealed: 10 Months of Boxing, Dumbbells and More

June 24, 2022

7 mins read

From the moment photos of Natalie Portman in “Thor: Love and Thunder” surfaced, the internet was swift to comment on how bulky her arms were.

In the Marvel film, opening July 8, Portman returns as Jane Foster/The Mighty Thor. This time around she is wielding Mjolnir, Thor’s Hammer, and she has the newfound power to throw lightning.

Fitness trainer Naomi Pendergast at Australia’s RPX Fitness was the person responsible for getting the actress ripped, developing Portman’s biceps and giving her abdominal definition.

What muscle groups did you focus on with Natalie for the film?

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.

How many weeks did you have to work on this transformation?

We started five months before filming and continued to train throughout the filming process to maintain her muscle. The total time we trained for the movie was around 10 months.

Once you had the goal established, how did you work on helping her bulk up — particularly the arms?

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.

What was a typical warmup routine?

Warming up would usually consist of various body-weight, Swiss ball, or band exercises to fire up the system and get the body connecting well. Stretches are sometimes included in the warmup, but I mostly use exercises that activate weak muscles rather than just stretching the tight muscles. Warming up in this way ensures everything is switching on as it should before we put heavy loads onto her body

Did Natalie encounter any injuries while training?

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.

How many hours would you work together?

We worked every day for around 1½-2 hours, depending on her schedule. Once filming started, Natalie’s schedule was very busy so we would train early, around 4:30 a.m., before she started for the day.

How did the pandemic impact your routine?

Initially, we trained at her house — as it was in the middle of lockdown — which meant using mainly free weights to do our training. Once filming started, we were able to work out in a gym, which meant we had access to a lot more for our sessions, which was great.

Can you break down in detail her nutrition and what went into a typical meal?

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.

What went into her workout regime — squats, lifts equipment?

On the days we lifted weights, we would focus on the quality of the reps and the gradual increase in load. On the other days that we trained, we would mix the workout up to keep it fun and interesting. A typical strength session for her upper body would include:

A good warmup using body-weight exercises, bands and gliding discs, which focused on bringing the upper body into alignment so we could maximize the strength benefits.
We would then do a main set of exercises which would include supersets with around a one-minute stretch rest between each set.

Superset 1:

• Dumbbell row — 10 slow reps

• Body-weight offset pushup — 10 slow reps

• Lat stretch (rest exercise)

Superset 2:

• Dumbbell reverse fly — 10 slow reps

• Dumbbell seated shoulder press — 10 slow reps

• Back stretch (rest exercise)

Superset 3:

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

• Assisted pull ups — 6-8 controlled reps

• Roll up (rest exercise)