How hard is Jessica Biel’s Matchbox workout? A trainer unpacks every move

One of our favorite celebrities spreading the word about strength training is Jessica Biel.

The internet went bananas for the arm and back workout she posted in December 2025, and now she’s sharing footage of how she physically prepared for her role in Matchbox The Movie.

Her latest post features commentary from her long-time trainer Ben Bruno and opens with a clip of her on set in a green backless dress.

“People understandably want to know about her back workout—the thing is, Jess does full-body workouts and actually focuses a bit more on legs and butt than upper body,” Bruno says in the clip.

He also adds that Biel tweaked her lower back a few months before getting ready for the movie, so he had to get creative to keep challenging Biel without aggravating her back.

Two moves in the video, the squats which use a foam roller, are great examples of that creativity, and could help some people squat while reducing the pressure on their lower back.

But the exercises Biel is performing are very advanced, and shows the strength she’s already working with. The moves combine isometric holds (a technique Alison Brie also uses to develop strength without bulk), balance through core stabilization and weighted compound movements (exercises that employ multiple muscle groups at once).

I put my personal trainer hat on to take a look at the exercises Biel’s doing and how they’re useful.

Horizontal ring row with forward slide

Gymnastic rings are a fantastic way to build strength across your upper body.

This move targets all the posterior muscles (those that run along the back of your body) —rhomboids, trapezius, rear deltoids and latissimus dorsi—combined with core strength for stability, particularly in the forward shift with bent knees.

In the hold at the top of the movement, your shoulders are actively retracted, improving shoulder strength and stability.

Wall-assisted goblet squat

This squat against the wall with a foam roller is a more supportive way to squat, targeting your quads, glutes and hamstrings, while bolstering your posture and protecting your lower back.

Adding weight increases the intensity and core resistance.

Wall-assisted double dumbbell squat

This wall-supported squat has the same setup with the foam roller behind the back, but holding two dumbbell weights instead of one at your chest.

The difference allows you to load more total weight, challenging your grip strength and upper back and shoulder muscles.

Wall-assisted double dumbbell Bulgarian split squat

This is a variation on the traditional Bulgarian split squat where the top of the rear foot rests on a weight bench. By pressing the sole of your back foot against a wall instead, it shifts more of the work onto your front leg.

It also makes your glutes work harder than your quads, changing the focus of the strength work.

High-side plank with resistance band knee and elbow drive

This is an advanced core and hip strengthening exercise where the resistance band (hooked onto an anchor point out of shot) forces your core to resist the band pulling you out of position.

As you drive your knee and elbow close together, your core has to work hard to keep you stable and balanced.

Resistance band weighted lateral lunge

The resistance band on an anchor point for this weighted lateral lunge creates horizontal tension, forcing Biel’s core and hip stabilizers to work harder.

Loading the movement by reaching a weight to the floor trains mobility and depth of movement. The challenge here is resisting the forward pull from the weight simultaneously with the side pull of the resistance band.

Bulgarian split squat hold with lateral raise

This is a traditional Bulgarian split squat with your rear foot on a weight bench but held at the bottom of the movement in an isometric position.

This unilateral move challenges your balance and stability, quads and glutes, with an extra demand from the single-arm dumbbell side raise, working your deltoids.

Raising your arm out to the side while in a low split squat forces your core to keep your pelvis stable against wobbling or twisting.

Side-lying press and reach

This is more of a mobility move to improve general shoulder mobility and scapular health. These smaller movements with lighter weights ensure you can do the heavier lifting with less risk of injury.

Once you’re lying sideways on a bench up to the hips, you press a light weight out in front of you at shoulder height, then raise it overhead.

Biel has her legs locked in place by husband Justin Timberlake, but you could also use a glute-ham developer machine in the gym.

Low-side plank with leg raise hold

This side plank hold is extra challenging with the leg raised. Raising the arm overhead makes the move even harder because your obliques (side abdominal muscles) have to work harder to keep you stable. It also engages your upper back and shoulders, preventing your chest from collapsing forward.

Keeping your raised ankle flexed ensures engagement through your side hip and glutes.