The Arm Workout Natalie Portman Did to Prepare for Her Role In 'Thor: Love and Thunder'

Getty Images

Natalie Portman is returning to the Thor franchise in Thor: Love and Thunder as the Mighty Thor, a transformed version of the character, astrophysicist Jane Foster, whom she played in past Thor films. Unlike many of Portman's former roles, this part involved the actress making serious gains in preparation to portray the comic book character. (Related: Scarlett Johansson's Trainer Reveals How to Follow Her 'Black Widow' Workout Routine)

"On Black Swan, I was asked to get as small as possible," Portman told Variety in a recent interview. "Here, I was asked to get as big as possible. That's an amazing challenge — and also a state of mind as a woman," she said.

In order to get into superhero shape, Portman worked with certified Pilates instructor, personal trainer, and triathlete Naomi Pendergast, director at Real Performance Exercise (RPX). "It wasn't just about having big muscles," Pendergast tells Shape. "Her role involved learning various stunts that required her to have a strong core and an agile ability to land well. I was definitely surprised at how intense the physical side of the role was," she adds. (See: Brie Larson Opened Up About the Self-Confidence She Gained from Playing Captain Marvel)

Pendergast "had to introduce heavy weights" into Portman's fitness routine for the role, she explains. Training also involved running, an activity both Pendergast and Portman enjoy. "Natalie loves to run, so we would head out a couple of times a week for a scenic run and include some sprints on the treadmill in our gym sessions," says Pendergast. "I am a triathlete myself, so I have a huge love for running, [and] I was very impressed with Natalie's natural form and her ability to run fast," she adds.

Despite long days on set, Portman got up for "extremely early" workouts, according to Pendergast. "Natalie is a very focused and self-driven person," says the trainer. "Even though her workload was really tiring during this time, she always turned up and gave 100 percent," she adds.

If you're curious how exactly Portman got her superhero-strong muscles, keep scrolling for one of her arm workouts, courtesy of Pendergast. Plus, you can take advantage of an exclusive offer for Shape readers in the RPX Fitness app. Use code Fitwomen to receive your first month free when you sign up for the gym and fitness program.

Natalie Portman's Arm Workout

How it works: Do the warm-up exercises for 30 seconds each. Then do 3 sets of each exercise in the following five supersets for the listed number of repetitions. Rest for 30 seconds between each set.

What you'll need: a set of dumbbells and a long resistance band

Warm-Up

Power Band Squat Press

A. Stand with feet hips-width apart and loop a long resistance band beneath feet, holding the other end in both hands at chest height.

B. Bend into the squat, making sure to keep the weight in heels and knees over ankles.

C. Keep elbows tucked in and drive arms up overhead without lifting shoulders toward ears.

D. Maintain the weight in heels throughout.

Do as many reps as possible (AMRAP) for 30 seconds.

Power Band Reverse Fly

A. Stand with feet hips-width apart and hold a long resistance band folded in half in both hands with arms held straight out in front of shoulders.

B. Open shoulders as you open arms out to the sides, making sure not to arch back.

C. Close arms slowly and with control, so you maximize muscle recruitment in shoulders.

D. Keep the weight planted evenly through your feet.

Do AMRAP for 30 seconds.

Power Band Single-Arm Shoulder Press

A. Stand with feet hips-width apart and loop a long resistance band beneath left foot, holding the other end of the resistance band in right hand.

B. Starting with right arm crossed down in front of left hip, press right arm up diagonally above right shoulder without shifting weight.

C. Keep right shoulder down as right arm goes up and keep the weight planted evenly in feet throughout.

Do AMRAP for 30 seconds, then alternate sides.

Superset 1

Do 3 sets of each exercise, resting for 30 seconds at the end of each set.

Dumbbell Single-Arm Row

A. Start with palm of right hand and bent right knee on bench, standing on left foot with a dumbbell in left hand.

B. Keep supporting right shoulder over right wrist and maintain a flat back.

C. Bend left elbow up, focusing on keeping left elbow tucked into side of body and left shoulder open.

D. Extend left elbow down while maintaining shoulder engagement.

Do 12 to 15 reps.

Dumbbell Overhead Raise

A. Lay down on back with bent knees and feet flat on bench, holding a dumbbell in both hands with straight arms above chest.

B. Slowly raise arms over head without arching back.

C. Draw shoulders down toward hips, so you feel the backs of your arm and base of shoulders working.

D. Return to dumbbell starting position with straight arms above chest.

Do 12 to 15 reps.

Superset 2

Do 3 sets of each exercise, resting for 30 seconds at the end of each set.

Dumbbell Straight Arm Raise (Palms Up)

A. Kneel on the ground with knees hips-width apart and arms at sides with one dumbbell in each hand.

B. Raise right arm up to shoulder height without lifting shoulders up, keeping body still throughout.

C. Lower right arm slowly, so you don't use momentum.

Do 20 repetitions, alternating sides.

Reverse Plank

A. Start sitting on the ground with legs straight out in front of you and arms straight with palms on the ground beneath shoulders.

B. Press up through hips, digging heels into the ground.

C. Press out of hands at the top, so you feel back of shoulders engage.

D. Slowly lower hips without resting on the ground.

Do 20 reps.

Superset 3

Do 3 sets of each exercise, resting for 30 seconds at the end of each set.

Dumbbell Arnold Press

A. Kneel on the ground with knees hips-width apart and arms held out to sides with bent elbows and one dumbbell in each hand.

B. Press dumbbells up overhead, straightening elbows and keeping shoulders down.

C. Bend elbows and lower arms back down through center to starting position with control.

D. Keep wrists, elbows, and shoulders in line throughout the movement, and keep center of body still throughout.

Do 12 to 15 reps.

Side Plank with Twist

A. Start in side plank position with left hand under left shoulder, right hand raised in the air, and feet staggered.

B. Press out of supporting hand, so you feel base of bottom shoulder engage.

C. Lift the hips as you reach right hand under the body, twisting down toward the ground.

D. Squeeze inner thighs.

E. Lower hips back to neutral side plank position as right arm lifts back in the air above right shoulder.

Do 12 to 15 reps, then alternate sides.

Superset 4

Do 3 sets of each exercise, resting for 30 seconds at the end of each set.

Dumbbell Bicep Curl

A. Kneel on the ground with knees hips-width apart and arms at sides with one dumbbell in each hand.

B. Keep elbows tucked into side of body.

C. Curl hands into shoulders without shifting elbows forward.

D. Slowly lower arms down with control.

Do 12 to 15 reps.

Power Band Wood Chop

A. Start in lunge position with left foot in front and left knee bent at a 90-degree angle. Keep right knee on the ground bent at a 90-degree angle with right toes untucked.

B. Hold folded long resistance band attached to a wall to the right side of body in both hands with arms straight.

C. Rotate to the left from chest and shoulders.

D. Keep hips and left knee still throughout, and lean upper body slightly forward over left knee.

E. Rotate arms back to the right from chest and shoulders.

Do 12 to 15 reps, then alternate sides.

Superset 5

Do 3 sets of each exercise, resting for 30 seconds at the end of each set.

Dumbbell Tricep Press

A. Start with knees on the ground and toes untucked. Rest right hand on top of a block on the ground and hold a dumbbell in left hand.

B. Keep left elbow tucked into side of body.

C. Extend left elbow out while keeping left shoulder open.

D. Maintain supporting right shoulder over right wrist.

E. Keep back straight/neutral throughout.

Do 12 to 15 reps, then alternate sides.

Jump Squat

A. Stand with feet hips-width apart.

B. Bend from hips first then knees and jump upward, swinging arms back behind torso as feet lift off the ground.

C. Get heels down each time you land and reach arms forward.

D. Keep knees behind toes and breathe throughout.

Do 12 to 15 reps.