Jessica Biel Demos a “Lunge Matrix” That’s a Whole Leg Workout in 1 Move

Celebs may have access to the best trainers, the fanciest equipment, and the most advanced tech to pursue their health and fitness goals, but they need to train more or less the same way as us common folk do: by working hard in the gym.

Jessica Biel‘s latest workout clip is proof of this. In the video posted on her Instagram, Biel carefully works through a simple-yet-challenging move — a three-way balancing “lunge matrix” — while holding onto a dumbbell. Her trainer Ben Bruno reposted the clip the next day, praising Biel for her balance skills and work ethic despite the distractions of Biel’s husband, Justin Timberlake, who’s dancing on the other side of the room.

“@jessicabiel is such a badass,” Bruno wrote in the caption. “This 3-way lunge matrix is hard enough as it is, let alone with @justintimberlake trying to distract you with his dancing 😂. She’s the only person I know who can do the whole set without tapping the other leg down for balance. Very, very impressive.”

You can do this lunge matrix with just your bodyweight or while holding a weight in front of your chest, like Biel. To do it, step back into a reverse lunge, then step forward with the same foot into a forward lunge, then step out to the side with the same foot into a lateral lunge — each time returning to standing but without tapping your foot on the floor. (To modify, you can step your lunging foot on the floor between lunges.)

This move works your entire lower body, including your quads, hamstrings, glutes, hip flexors, and inner and outer thighs. It also challenges your balance (and thus your core strength) and forces your body to move in multiple planes of motion, which is great for building functional strength.

This isn’t the only time we’ve seen Biel and Bruno work together on a winning workout. The pair have been training together for several years, including leading up to the Emmys in 2018. Bruno also works with model Kate Upton, coaching her through impressive feats including 225-pound hip thrusts, and comedian Chelsea Handler, among others.

Biel initially shared the lunge video to tell others about Bruno’s new 6-Week Starter Pack, which includes a mobility routine, three strength workouts per week, and accompanying nutrition info. “Ben just launched the coolest / easiest new program to help people get back on track in 2023 — eating healthier, getting stronger — it’s so thorough . . . cannot recommend it enough,” Biel wrote in the Instagram caption.

He was clearly thankful. “To have her support my program means a lot to me personally, and to see her inspire so many women to get strong is so awesome.” he wrote in his caption. “Thanks, Jess!”

And thanks, Bruno and Biel, for the killer leg move — though we’ll blame you when we’re sore tomorrow.