“The joke was, ‘I’m about to be naked for six months,’” says Gunnar Peterson, the Beverly Hills fitness guru who, together with New York–based trainer Kacy Duke, helped get Dakota Johnson in shape ahead of the filming of Fifty Shades Darker. In order for Johnson to look and feel her best while nude, Peterson and Duke devised a regimen of combination moves that target what Peterson calls the “Triple A” (abs, arms, and ass). To do so, they favored exercises—such as a squat with a twisting press—that hit all three planes of motion: sagittal, frontal, and transverse. “For what Dakota is doing in the movie—the way her body moves—she needs to be capable of all that,” Peterson says.

Duke, meanwhile, focused on fluid, elongating exercises, such as the “Goddess,” a knee lift into a back lunge lifted into an arabesque, which required both control and grace—two qualities Duke considers crucial for feeling sexy. The moves not only sculpted Johnson’s body, but also instilled in her a sense of confidence: post-workout, “Dakota would always say, ‘I’m walking like a cat,’” Duke recalls.

While filming in Vancouver and Seattle away from Peterson and Duke, Johnson mixed yoga classes with a 45-minute personalized routine from Duke. Key were light 3-to-5-pound hand weights; a 4-pound medicine ball, which she used for side lunges; and a chair to hold onto. Here, Duke breaks down the moves—just in time for Valentine’s Day.

THE PUSH-UP TRI-FECTOR
Equipment: Two small towels or a pair of gliders
Muscles Targeted: Abs, arms, chest, back and legs, plus the heart with its cardiovascular kick!
Reps: Three sets

• Starting in plank position, hands a little wider than shoulder-width
  apart, place a towel or glider under each foot.

• Start with one push-up. If you’re unable to do a full push-up, remain
  in plank position.

• Transition into basic pull-ins, bringing your knees toward your
  shoulders, then straight back three times in a smooth movement.
  Complete three mountain-climbers.

• Go directly into three pull-ins with open/close legs at the end.

• Rest for 30 to 60 seconds.

• Repeat 2 more times.

WARRIOR 1
Equipment needed: A chair; a weighted bar for balance
Muscles worked: Every muscle fiber in your hips, thighs, and buttocks
Reps: Three sets of 8 to 12 reps on each leg

• Stand in the power position, feet slightly apart.

• Place your left hand on your hip. Hold onto a chair or body bar for
  support.

• Lift your right leg so it’s bent at a 90° angle and your knees are
  even with your hip.

• Swing your right leg back into a deep lunge position so that it’s
  bent as close to 90° as possible, with the ball of the foot on the
  ground (heel lifted). Your left leg should form a 90° angle, with
  your knee directly over your ankle.

• Return to the starting position but don’t pause. Immediately flow
  into the next rep in a fluid motion. Complete a full set (8 to 12
  reps) without pausing, and then switch sides.

NEW YORK BOOTY LIFT TRI-FECTOR
Equipment needed: 2 lb. to 5 lb. weights in each hand
Muscles worked: Butt, thighs, and arms
Reps: Three sets of 8 to 12 reps on each leg

• Start in a lunge position with a weight in each hand making sure your
  front knee is directly in line with your heel. Lunge up and down as
  you do a bicep curl with each movement for a count of 8 or 12.

• Hold the last rep in the lunge position.

• Straighten the back leg, lifting the heel off the floor and staying
  on the ball of the foot.

• Moving the upper torso only, rock forward and back 8 to 12 times,
  making sure to keep your back and arms straight without rounding
  shoulders.

• Hold the last rep; slowly pull your elbows behind you, and without
  moving your legs or upper body, do 8 to12 triceps kick-backs. Switch
  legs and complete full circuit before resting.

PUSH, PULL, KICK-BACK
Equipment: 2 lb. to 3 lb. weights in each hand
Muscles targeted: Chest, back, shoulders, triceps (bonus: booty and thighs get a nice burn!)
Reps: Three sets of 12 reps

• Assume a squat position with your legs bent about 45 degrees.

• Hold a weight in each hand with arms bent so that weights are
  positioned just in front of your chest, palms facing each other.

• Extend your arms straight out in front of you, pushing the weights
  forward.

• Bend your elbows, squeeze your shoulder blades together, and pull the
  weights back to either side of your chest. Straighten your arms out
  behind you.

MASTER BLASTER
Equipment needed: Chair
Muscles worked: Glute and hips
Reps: Three sets of 12 reps on each leg

• Stand with feet hip-width apart, lean forward from your hips and
  grasp the back of the chair so that your back is flat and parallel to
  the floor.

• Raise and extend your right leg straight out behind you, allowing
  your left leg to bend slightly.

• Pulse your right leg up and down 12 times.

• Pull your right knee to your chest and then extend the leg back out
  12 times.

• Bend right leg so your knees are in line and your right shin parallel
  to the floor.

• Lift your bent right leg out to the side, extending it straight out
  at the top of the lift. Lower, and repeat 12 times.

• Switch legs.